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Comments 128851 to 128900:

128851. Patrick 027 at 13:15 PM on 17 February 2009
        Arctic sea ice melt - natural or man-made?
        "would have to know the EXACT nature of ALL inputs " With regards to the difference between 2 and 3.0001, what would you say about the difference between 2 and 2.9999 ?
128852. Quietman at 07:19 AM on 17 February 2009
        Arctic sea ice melt - natural or man-made?
        ps I discussed with mu friend the use intended and he agreed that it does apply to this argument as well. So it actually is not out of context.
128853. Quietman at 07:14 AM on 17 February 2009
        Arctic sea ice melt - natural or man-made?
        Philippe Actually it's the hockey stick site. And yes I will read a link that goes to RC when it's used as a reference to see what it refers to, I just don't go there on my own accord. As for chaotic inputs, there are simply too many. The earth breathes much more often than thought, the solar wind has erractic effects and tectonics which nobody at this site appears to understand the consequences of. Then chris reads the terms for Thermodynamic Laws, which were intended for use in engineering closed systems ONLY and tells me that they can be applied to climate. Sorry but that IS where this whole argument falls through. They DO NOT apply to open systems. In order to make these rules apply to an open system you would have to know the EXACT nature of ALL inputs and the simple fact is nobody alive knows these. The evidence is in the CONSTANT discovery that things are not what they appear to be. And I REALLY have trouble accessing this thread at this point. My references have already been posted in the various threads at this site (mostly under volcanos) so I am not posting them again.
128854. Philippe Chantreau at 04:18 AM on 17 February 2009
        Arctic sea ice melt - natural or man-made?
        Worth quickly getting back on topic: Arcic sea ice extent has taken a serious hit and would have to grow now at the same kind of rate seen in November to catch up with last year's maximun. Kinda strange. I expect some weather system pushing the ice around and possibly compacting it, but area as shown by cryosphere today seems to have the beginning of a dip also. Hard to tell what's going on. http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/current.365.jpg http://nsidc.org/data/seaice_index/images/daily_images/N_timeseries.png
128855. Philippe Chantreau at 16:47 PM on 16 February 2009
        Arctic sea ice melt - natural or man-made?
        Patrick, I recall Quietman saying that he did not trust RC and, as a result, did not read it, althoug his readings (and links) have included niceties like the OISM page. That's the point of my question above. Nice link on Singer. This is the kind of reason why I'm always septical of "skeptics" on blogs. As of today I've seen perhaps 2 or 3 real ones. Ironically, they wouldn't even shape their thinking in terms of "agreeing" or "disagreeing" with AGW, wchich is a little to crude a way to put things.
128856. Patrick 027 at 10:38 AM on 16 February 2009
        Arctic sea ice melt - natural or man-made?
        "How can limits of a system be properly defined is the system has been determined to be chaotic?" The Earth isn't chaotically gaining and losing significant amounts of mass, even relative to the atmosphere. Aside from that: Divide space (or space-time) into some number of grid cells. Identify the energy, entropy, mass (in terms of chemicals, subatomic particles, etc.), and momentum and angular momentum flows into and out of each cell (define the cells to move with the mass when convenient - for example, define a system that orbits the sun along with the Earth, rather than having the mass of the Earth constantly pass through different grid cells). Identify the chemical and physical reactions within each cell. Balance the energy, entropy, mass, and momentum budgets. DONE! The long term equilibrium climate includes the shorter-term variability. The shorter term variability continues in part due to positive feedbacks but is limited by negative feedbacks that keep the climate within a certain range of behavior; external forcing shifts the whole of such an equilibrium state and positive feedbacks can contribe to that shift. "besides, didn't you just smear Fred Singer?" Fred Singer is either a fool or a liar - or blinded to the truth by some ideology. Who am I to deny him that title, for which he has worked so hard; he has earned it. (try starting with comment 218 at: http://www.realclimate.org/index.php/archives/2008/08/are-geologists-different/langswitch_lang/it )
128857. Quietman at 08:07 AM on 16 February 2009
        Volcanoes emit more CO2 than humans
        Patrick You might find this interesting: Rift Zones: New Understanding Of Incredible Forces, Oil And Gas Reserves Beneath The Earth’s Surface ScienceDaily (Feb. 12, 2009)
128858. Philippe Chantreau at 18:56 PM on 15 February 2009
        Arctic sea ice melt - natural or man-made?
        Quietman, you declared once that one of the RC contributors (you did not specify) was untrustworthy because of some political reason or source of funding, although you gave no specifics. Your judgement in the matter did not take into consideration the scientific quality of his work, which is a fairly objective measure (i.e. the Spencer "claim" detailed above as example of sloppy work). Fair enough, you're entitled to your opinion on that. I can understand that would leave aside one scientist's work because you don't like his ideas. Nonetheless, I would think that some level of reciprocity would apply to scientists with ideas you like (what a true skeptic would do), even if you could understandably be more complacent. We're still talking about science here. However, you had no problem spreading links to Marc Morano's propaganda. Morano is not a scientist at all, he is a PR professional working for a politician. What excactly is the rationale here?
128859. Quietman at 18:30 PM on 15 February 2009
        Volcanoes emit more CO2 than humans
        Volcanic Eruptions Greater than 4.0 Period from 1945 to 1970 (16 major eruptions) Nomen Year Rank Location FERNANDINA 1968 4 Galapagos AWU 1966 4 Sangihe Islands KELUT 1966 4 Java TAAL 1965 4 Luzon SHIVELUCH 1964 4+ Kamchatka AGUNG 1963 5 Lesser Sundas AGUNG 1963 4 Lesser Sundas BEZYMIANNY 1956 5 Kamchatka CARRAN 1955 4 Chile SPURR 1953 4 Alaska BAGANA 1952 4 Bougainville Island KELUT 1951 4 Java LAMINGTON 1951 4 New Guinea AMBRYM 1951 4+ Vanuatu HEKLA 1947 4 Iceland SARYCHEV 1946 4 Kuril Islands Period from 1971 to 2006 (26 major eruptions) Nomen Year Rank Location RABAUL 2006 4 New Britain MANAM 2005 4 N.E.of New Guinea REVENTADOR 2002 4 Ecuador RUANG 2002 4 Sangihe Islands SHIVELUCH 2001 4 Kamchatka ULAWUN 2000 4 New Britain RABAUL 1994 4 New Britain LASCAR 1993 4 Chile SPURR 1992 4 Alaska HUDSON 1991 5+ Chile PINATUBO 1991 6 Luzon KLIUCHEVSKOI 1990 4 Kamchatka KELUT 1990 4 Java AUGUSTINE 1986 4 Alaska CHIKURACHKI 1986 4 Kuril Islands COLO 1983 4 Sulawesi GALUNGGUNG 1982 4 Java CHICHON 1982 5 Mexico CHICHON 1982 4+ Mexico PAGAN 1981 4 Marianas ALAID 1981 4 Kuril Islands ST.HELENS 1980 5 Washington AUGUSTINE 1976 4 Alaska TOLBACHIK 1975 4+ Kamchatka FUEGO 1974 4 Guatemala TIATIA 1973 4 Kuril Islands Source: http://www.volcano.si.edu/world/largeeruptions.cfm Results: 10 more eruptions recently with a VEI >=4 than for the same length preceeding period using 1970 as a cutoff. Note: I have no access to the additional activity or the undersea volcanos that are not included.
128860. chris at 11:15 AM on 15 February 2009
        Arctic sea ice melt - natural or man-made?
        re #445:

        How can limits of a system be properly defined is the system has been determined to be chaotic?

        Again, you need to be explicit. Are all the elements of the system "chaotic"? Are the dominant elements of the system chaotic? Or not? If only some elements of the system are chaotic, what is the amplitude of variation around the equilibrium "set" by the non-chaotic elements of the system....and so on... So we could go back to the Earth's surface temperature. There's nothing particularly chaotic about the Earth's atmospheric composition, and the forcing resulting from the greenhouse effect. Likewise the vastly dominant source of energy into the system (the sun) isn't particularly chaotic as a source of heat energy. The level of solar irradiance drifts up and down slightly with an 11 year cycle in an essentially non-chaotic manner, and the solar constant increases interminably slowly on the multi million year timescale (also non-chaotic), occasionally the solar output does drift slowly upwards or downwards within a relatively small range. So in general it's the internal elements of the climate system that are chaotic. But the evidence indicates that these chaotic elements (outwith extremely rare catastrophic events like extraterrestrial impacts or massive tectonic eruptions) result in "noise" that has a relatively small amplitude. We can see explicitly that El Nino's and La Nina's can temporarily enhance or reduce the Earth's globally averaged temperature by 0.1 - 0.2 oC, that ocean cycles that redistribute warm and cooler waters during rather longer timescales can have similarly small effects on the globally averaged surface temperatures....volcanic eruptions can temporarily suppress temperatures for a few years... …in general (outwith catastrophic phenomena, or small non-predictable variations in solar outputs, such as those associated with the Maunder minimum and such-like) the dominant influences on the Earth’s energy budget aren’t particularly chaotic, and the chaotic elements result in “ noise” characterized as fluctuations around the equilibrium temperature “set” by the dominant forcings (sun, greenhouse effect and the particular extant properties of the Earth like the positions of the continents and mountain ranges, and the Earth’s orbit). ..so again, we need to be explicit about what we’re considering.
128861. chris at 10:48 AM on 15 February 2009
        Arctic sea ice melt - natural or man-made?
        re #442:

        chris: First off, one can certainly apply the laws of thermodynamics to an open system. It only requires that the limits of the system are defined in the context of the particular analysis." Quietman: “No, limits of the system can not be properly defined”

        Of course the “system” can be defined. One just has to be explicit about the phenomenon under discussion. So if the evidence indicates that the Earth’s “energy budget” is defined by the forcings arising from the Earth and the elements of its climate system (the land, oceans, atmospheric composition, continental locations, mountain ranges, air and ocean currents, land and sea ice, orbital properties..etc), and the sun and its properties that defined the insolation levels, then these are the elements that “define” the “system”. We might choose to consider other elements under quite specific circumstances. On the 100 million year timescale we might choose to incorporate the passage of the solar system through the spiral arms of the galaxy, and thus consider variations in the cosmic ray flux and its putative climatic influences. And then we would incorporate this into the “definition” of our “system”. Of course this is of little relevance to the effects of changing greenhouse gas levels over several decades or centuries. Or we might choose to consider the Earth’s temperature response to forcings resulting from asteroid impacts or massive tectonic events. Again this isn’t of much relevance to our consideration of the Earth’s evolution to a new equilibrium temperature defined by an enhanced greenhouse forcing under consitions of relatively constant insolation…. …and so on… So the “limits of the system “ can be properly defined. It’s a question of being clear and explicit about what we are addressing.
128862. chris at 10:10 AM on 15 February 2009
        Arctic sea ice melt - natural or man-made?
        You don't really understand Quietman. I made a specific point about the Earth's temperature response to an enhanced forcing. Your friend posted some unrelated stuff about entropy and thermodynamics. I'm not trying to disprove your friends "definitions". Why should I want to do that? Your friend's "definition" have no bearing on my post. That's not very surprising since s/he apparently wrote in a context completely unrelated to my post. If you can't address the subjects of my posts Quietman, just keep schtum. It doesn't make any sense to trawl the blogosphere to find someone else's post that might have some vague relationship to mine! If you think I'm "denying" some well-characterized climate cycles, why not just direct me to the relevant post? You can give the url of the relevant thread, and all the posts on every thread is numbered. Just post the url(s) and the post number(s). Otherwise please stop making unsupported accusations insinuations. As for "equilibria" in relation to the Earth's surface temperature:... A considerable amount of scientific analysis supports the conclusion that the Earth's surface temperature responds to enhanced greenhouse forcing with a rise near 3 oC per doubling of atmospheric CO2 (between 2 - 4.5 oC at 95% certainty according the the IPCC compliations of the available evidence). Right now the Earth's temperature is fluctuating around a temperature "set" by the current solar irradiance and greenhouse gas levels (and incorporating insolation patterns, albedo and water vapour feedbacks, atmospheric aerosol levels, the position of the continents and location of major mountain chains, and so on). The Earth's temperature isn't rock steady, but undergoes fluctuations around the equilibrium temperature that results from the summation of forcings; these fluctuations are a result of cyclic and stochastic elements of the climate system. If the atmospheric CO2 levels double, the Earth's temperature will evolve towards a new equilibrium temperaure that will be somewhere around 3 oC warmer than the temperature around which the earth currently fluctuates. It's useful to understand that this temperature rise is the rise that will occur at equilibrium, since we understand very well that the inertias in the climate system (e.g. the massive ocean thermal sink) have the effect of damping the Earth's temperature response to a change in forcings. In other words, while the evidence indicates that the Earth's temperature response to enhanced greenhouse forcing is around 3 oC per doubling of atmospheric CO2, this temperature change will take many decades to be fully realized. That's a very straightforward, uncontroversial, and explicit use of the concept of equilibrium in relation to the Earth's surface temperature response to a change in forcings. If you feel the need to quibble with that, please do so on the terms of my post, rather than through completely unrelated notions of "thermodynamic laws" or "closed systems" or other extraneous stuff that someone might have posted on some blog somewhere.
128863. Quietman at 09:43 AM on 15 February 2009
        Arctic sea ice melt - natural or man-made?
        Patrick Sorry, but this page has become too long and takes forever to load. I'll look to see your posts in other threads. But I will leave you here with this thought: How can limits of a system be properly defined is the system has been determined to be chaotic?
128864. Quietman at 09:38 AM on 15 February 2009
        Arctic sea ice melt - natural or man-made?
        correction to 442 Re: "new equilibrium temperature": This phrase discusses thermodynamic laws, implying a closed system. The earth has no equilibrium temperature, it constantly changes. GHGs do control it's limits but never achieve "equilibrium" because the earth "breathes".
128865. Quietman at 09:37 AM on 15 February 2009
        Arctic sea ice melt - natural or man-made?
        ps Who is Fred Singer? The name sounds familiar.
128866. Quietman at 09:30 AM on 15 February 2009
        Arctic sea ice melt - natural or man-made?
        Patrick Sometimes a smear is truly deserved ("we are all toast" Hansen); besides, didn't you just smear Fred Singer? Is turn about not fair play? Is it not "we are all toast" Hansen who smears everyone else on the planet that disagrees? Re: "First off, one can certainly apply the laws of thermodynamics to an open system. It only requires that the limits of the system are defined in the context of the particular analysis." No, limits of the system can not be properly defined.
128867. Quietman at 09:22 AM on 15 February 2009
        Arctic sea ice melt - natural or man-made?
        chris So you can't disprove my friends' definition just because he said it better than I could? You have not denied the existance of climate cycles? Go back and reread your responses. You have a short memory. You denied natural cycles the very first time I brought up the subject. Re: "new equilibrium temperature" discusses thermodynamic laws, implying a closed system. The earth has no equilibrium temperature, it constantly changes. GHGs do control it's limits but never achieve "equilibrium" because the earth "breathes".
128868. chris at 08:48 AM on 15 February 2009
        Arctic sea ice melt - natural or man-made?
        #432 How dishonest you are Quietman.

        Chris has demonstrated his true faith by attempting to apply the laws of thermodynamics to an open system. And when I post a good explanation using a quote from a friend that was able to better express it than I, he attacks me personally, just like you did.

        First off, one can certainly apply the laws of thermodynamics to an open system. It only requires that the limits of the system are defined in the context of the particular analysis. In any case, I haven't discussed the "laws of thermodynamics". I described a very basic response of the Earth's temperature to an enhanced forcing. I pointed out that the earth will tend towards a new equilibrium temperature around which fluctuations occur due to stochastic and cyclic elements of the climate system. There's nothing very controversial or mysterious about that.. Secondly, you didn't post " a good explanation". You cut and pasted a completely unrelated post of some person on some other blog written presumably for some other purpose. Thirdly, I didn't "attack" you "personally". I pointed out that your posts didn't address my post at all. And how could a "cut and paste" from some unrelated blog by some person who hasn't read my posts, constitute a response to my post on this message board?

        But I also see the rest of the picture that you and chris refuse to acknowledge, ie. you are both in denial of natural cycles, chris even moreso than you.

        Examples please. I'm not "in denial" of any "natural cycles" for which there is evidence. There's clearly an 11 year solar cycle. There are cycles involving ocean circulation (the PDO for example). There are ocean circulation variations that are apparently more stochastic in their temporal evolution (ENSO, for example). There are cycles in the orbital properties of the earth (Milankovitch cycles) that govern insolation patterns that drive glacial-interglacial-glacial transitions....and so on.. So which "natural cycles" am I "in denial of" Quietman? Specific examples, please. All of these topics involve science, evidence, rational analysis, and on this message board, honest attention to the postings of others. If you can't deal with these issues, and other's posts in that philosophy, why not just ignore the posts that you happen not to like?
128869. Patrick 027 at 06:44 AM on 15 February 2009
        Arctic sea ice melt - natural or man-made?
        "IF N increases with height, then LRS increases. This tends to decrease w. " I knew that didn't sound right! Increasing N while leaving m unchanged decreases the denominator [ k^2 + l^2 + (m*Hzs/LRS)^2 + 1/(4*LRS^2) ] and thus increases w. m must be proportional to N to maintain constant w. Thus, N increasing with height requires an increase in m to maintain constant w. u decreasing with height requries a decrease in w, requiring even more increase in m. Both effects tend to make the phase planes farther from vertical and closer to horizontal (the tilt away frome vertical increases). The vertical component of group velocity will generally increase at first as the tilt increases, but will reach a maximum value and then decrease. When u gets low enough, w goes to zero and then negative - and then m becomes large and imaginary (further decrease in u allows the magnitude of m to decrease but it will remain imaginary). the wave cannot propagate further. It may reflect back down; however, the variation of group velocity may cause the amplitude to become large at some level, to the point that there is wave-breaking, which is one way for wave activity to be absorbed in an irreversable manner, as described with regards to sudden stratospheric warmings (which reduce u, thus lowering the level to which the waves can propagate, etc...). Another thing that could happen is that where some component of group velocity is low, wave activity lingers, allowing more thermal damping to occur (the wave involves adiabatic temperature changes which tend to cause radiational cooling or heating). Clarifications: when a component of a wave vector is imaginary, the rate of exponential decay in that direction is proportional to that component's magnitude; thus the distance scale of penetration is inversely proportional to the magnitude, and thus is directly proportional to the magnitude of an effective imaginary wavelength. Regarding total internal reflection - the reflectance will of course be reduced if some wave energy is able to leak (tunnel - via the evanescent portion of the wave) across to a second interface where the wave can again propagate. --- Of course, temporal variations in wind can alter the result: If a wave propagates up to some level, and then the wind speed falls at that level, it takes the wave with it, so then the wave can propagate up further where the wind speed was lower, with less refraction. So short-term temporal variations in the basic state may also allow some leaks in the barriers to propagation.
128870. Patrick 027 at 06:12 AM on 15 February 2009
        Arctic sea ice melt - natural or man-made?
        "Patrick, Ann Coulter is nuts." No argument there! - unless we suppose that her value system is tilted towards notoriety and money and very far from truth (although that could also be said to be 'nuts'), in which case she is just making a living the way she wants to do it. Nice links!
128871. chris at 06:06 AM on 15 February 2009
        Is Antarctic ice melting or growing?
        Re #37 Your friend hasn't given an explanation. The post of your friend bears no relation to my post. You can't just copy a post from some other blog because it's vaguely related to the subject. Why not get your friend to answer my post? I'm not sure what your making such a song and dance over this anyway, since my posts on equilibria on this thread are completely non-controversial...
128872. Philippe Chantreau at 18:39 PM on 14 February 2009
        Arctic sea ice melt - natural or man-made?
        Patrick, Ann Coulter is nuts. Her crazy antics are the only stratageme she could muster to avoid being completely ignored. "Disprove those scientists." Let's take the example of Roy Spencer. Not only the errors in his UAH satellite data were noticed by others, they were also corrected by others, while Spencer and Christy merrily let all sorts of politically motivated individuals exploit the erroneous data, which they knew to be flawed. If any scientist not liked by deniers would go anywhere near such behavior, they'd asked for his/her head on a platter. But let's ignore that and just look at his more recent pastime: trying to show that the increased atmospheric CO2 owes nothing to human generated CO2. So far that has not gone well and led him to all manners of extravagant claims that "skeptics" trying to keep up appearances are trying to mitigate. However, it is the way he fumbled his maths on one of these claims that is really amusing. Spencer's "demonstration" is in this WUWT post: http://wattsupwiththat.com/2008/01/28/spencer-pt2-more-co2-peculiarities-the-c13c12-isotope-ratio/ It's rather funny that, with all their pompous tone, none of the posters notices how fundamentally flawed the mathematical argument is, until someone shows that you get the exact same result with any 2 unrelated time series subjected to the same treatment. Watts tries to divert attention from the core issue near the end, then he simply closed the thread for comments. Spencer's lack of understanding of his own maths is covered in this post: http://tamino.wordpress.com/2009/01/19/a-bag-of-hammers/#more-1435 That's a mathematical disproof, good enough?
128873. Patrick 027 at 17:22 PM on 14 February 2009
        Arctic sea ice melt - natural or man-made?
        "are your opinion, not fact. " It is probably their opinion that their points are facts or are backed up by the facts. PS it is a fact that my opinion is ____. It may be someone's opinion that ____ is not a fact. It may be a fact that an opinion can't be justified. FACT: Ann Coulter seems to think she has a right to her own facts...
128874. Patrick 027 at 17:14 PM on 14 February 2009
        Arctic sea ice melt - natural or man-made?
        Quietman - not to come down too hard on you (especially since I've forgotten what the paper with all the citations was about (I'd look now but I've got to go in a few seconds)), but: "Chris has demonstrated his true faith by attempting to apply the laws of thermodynamics to an open system. " There's nothing wrong with applying the laws of thermodynamics to an open system so long as one accounts for the openness of the system. One method of creationists is to IGNORE the openness of the system. "You cherry pick and so does chris, or should I say reverse cherry pick, selectively ignoring those parts in the paper that disagree and then interpreting those papers as either supporting your view or not supporting mine." Taking points in isolation may not support anything or else make for a confusing mess. If area A warms by Ta and area B cools by Tb, the areal average warms by (Ta*A - B*Tb)/(A+B). If that value is positive, it doesn not require ignoring Tb to recognize the average's sign (although one needs both the averages and the variations to get the complete picture, but one can ignore a single grain of sand on the beach and still calculate the mass of the Earth). "But I also see the rest of the picture that you and chris refuse to acknowledge, ie. you are both in denial of natural cycles, chris even moreso than you." Are they in denial or do they disagree with you about which natural cycles or variations are significant and which ones are not and the significance relative to anthropogenic effects? "Disprove those scientists you disagree with rather than attempting to smear their reputation." "You make yourself sound like a Hansen clone. If you can't disprove something then it's more likely true than coming from someone that's crazy. " Sometimes a smear is truly deserved (Fred Singer); besides, didn't you just smear Hansen?
128875. Patrick 027 at 16:57 PM on 14 February 2009
        Arctic sea ice melt - natural or man-made?
        Refraction: Okay, so these waves propagate, and w depends on the wave vector (among other things: Hzs, N, f (or AV and f_loc..., beta (or more generally the IPV gradient))... w is relative to the air as it moves. the phase speed in the x direction = cx = w/k. This is the speed through the air. The air moves, so to find the speed in the x direction relative to the surface, one must the x component of the (basic state) wind, u. Generally, for figuring out wave refraction and reflection, it is easiest to assume constant w relative to a common reference frame (such as the surface, or perhaps following the air at a reference location in the atmosphere (one must then account for horizontal or vertical wind variations when considering the w following the air at other locations). Then, if there is an interface across which some conditions change, then the component of the wavevector parallel to that interface must be the same on either side, but the component perpendicular to the interface can change as sharply as the interface is sharp. This wave vector component must be adjusted to maintain the same phase speed in the directions parallel to the interface on either side, relative to a common reference frame. Then, considering a steady state condition, one must have no convergence or divergence of group velocity times wave energy density. Since the group velocity can vary across the interface, the energy density must vary as well. This may require a change in amplitude across the interface. In the vertical direction, the amount of vertical stretching can change sharply, but more generally, RV and vertical displacments will vary continuously. In order to avoid a discontinuity in total amplitude for an interface for which the amplitude difference between incident and refracted waves is nonzero across a relatively sharp interface, one can add the amplitude of a reflected wave on one side to make up the difference. Because the reflected wave also has group velocity and energy density (a function of amplitude), the nondivergence of wave energy flux and continuity of amplitude of wave fields (RV' and S'(? or vertical displacement?) - for an electromagnetic wave, the anology would be the amplitudes of the magnetic and electric fields of the wave) must be addressed together (a system of equations) to find the solution. Once such a steady state is found, one can consider states that evolve in time, by introducing wave packets - regions of nonzero amplitude waves - that propagate with group velocity, which partially reflect and refract at the interface and follow the group velocities of the reflected and refracted waves, respectively, with the proportion of energy going one way verses the other being determined by the solution of the aforementioned system of equations. The squares of the wave numbers appear in the dispersion relationship. With the components parallel to the interface being fixed, one must vary the components perpendicular to maintain the required w value. The situation can arise when the solution is that the square of the wave number goes to zero or is negative. In the zero case, the wave number must then go to zero, which means that the wave length in that direction is infinite (the phase planes are parallel to that direction). In the negative case, the wave number must be an imaginary number. This means that the wave fields do not oscillate in that direction but instead grow or decay exponentially. Exponential growth may be allowed if the wave energy is coming from that direction, but usually exponential decay is the solution that fits physical reality. This is an evanescent wave; it remains wavelike along the interface but decays in strength away from the interface and cannot propagate wave energy indefinitely away from the interface. However, some portion of the wave may penetrate all the way to another interface (that portion obviously exponentially decreasing with distance); if the wave can have real values of wavenumbers on the other side of that interface, then that portion of the wave activity can 'leak' through the barrier and propagate again after the second interface - the wave tunnels through the barrier, just as in quantum mechanics, the wave nature of an electron allows it to tunnel through barriers. IMPORTANT Example: for the planetary waves described by: w = beta*k / [ k^2 + l^2 + (m*Hzs/LRS)^2 + 1/(4*LRS^2) ] The phase speed = cx = w/k the phase speed in x relative to a reference level is u+cx = u + w/k Note that k is negative, so cx is negative. For an interface that is horizontal, we need to maintain constant CY = v+cy and CX = u+cx. Just considering u+cx: cx = CX-u w = k*(CX - u) = |k|*(u-CX) IF u decreases with height, w must decrease. IF N increases with height, then LRS increases. This tends to decrease w. To maintain constant w with increasing N, m^2 must increase. If changes in u cause w to go to a large enough value, the denominator [ k^2 + l^2 + (m*Hzs/LRS)^2 + 1/(4*LRS^2) ] must get smaller than [ k^2 + l^2 + 1/(4*LRS^2) ] while if w must go negative, then the denominator must go negative - either way there is a point where m^2 must also go negative, and the wave becomes evanescent. I think this also implies 'total internal reflection' - the reflected wave is as strong as the incident wave. More generally, if the interface is sloped, k and l might also change. A wave packet with some northward group velocity component might produce a reflected wave packet with some southward group velocity component, or maybe vice versa. The refracted wave's phase line orientation in the horizontal and it's group velocity direction in the horizontal may also be different...
128876. Quietman at 10:30 AM on 14 February 2009
        Arctic sea ice melt - natural or man-made?
        ps I compare AGW alarmists to creationists because they use EXACTKY the same tactics and arguments.
128877. Quietman at 10:29 AM on 14 February 2009
        Arctic sea ice melt - natural or man-made?
        Re: "You keep on citing stuff that does not support what you say it does and when called on that by Chris, you go on accusing him of bias or "not liking the authors" without ANY basis for the accusation. You give credence to far fetched ideas with a scant or non existent publication record while holding doubts on published ideas that have succesfully cleared authentic scientific scrutiny. When confronted with that, you resort to the tried and true, whiny excuse of creationists, i.e. "scientific journals are biased against our ideas so we can't publish." Pretty sad. You're not showing any true skepticism." Chris has demonstrated his true faith by attempting to apply the laws of thermodynamics to an open system. And when I post a good explanation using a quote from a friend that was able to better express it than I, he attacks me personally, just like you did. Your citations of my using papers that do not support my views are your opinion, not fact. You cherry pick and so does chris, or should I say reverse cherry pick, selectively ignoring those parts in the paper that disagree and then interpreting those papers as either supporting your view or not supporting mine. I acknowledge AGW, I do understand how GHGs function and fully realize that this would be a much colder planet without them. But I also see the rest of the picture that you and chris refuse to acknowledge, ie. you are both in denial of natural cycles, chris even moreso than you. Disprove those scientists you disagree with rather than attempting to smear their reputation. You make yourself sound like a Hansen clone. If you can't disprove something then it's more likely true than coming from someone that's crazy.
128878. Quietman at 10:02 AM on 14 February 2009
        Is Antarctic ice melting or growing?
        chris You did not like my answer so I posted a friends explanation. He knows much more than I do about theoretical physics than I do. My knowledge of physics is limited to that needed for engineering, ie. I had to work for a living, I'm not an academic. That fact that you also don't care for his explanation either is quite telling. ps I do not "hunt" the blogosphere. I asked a friend that had a better explanation than what I gave for permission to repost his comment from my daily visited science columns (not a blog, a news casting site that mostly covers evolution and paleontology (but also includes algoristic alarmist propaganda).
128879. chris at 06:32 AM on 14 February 2009
        Is Antarctic ice melting or growing?
        Re #35 I've addressed your point. Your response is to hunt around the blogosphere to find some post that seems like it might possibly be relevant to mine. In fact it isn't. If you can't answer for yourself, just leave it.
128880. Patrick 027 at 04:59 AM on 14 February 2009
        Arctic sea ice melt - natural or man-made?
        change Hs to Hzs to be clear: w = beta*k / [ k^2 + l^2 + [(m*Hzs)^2 + 1/4]/LRS^2 ] or w = beta*k / [ k^2 + l^2 + (m*Hzs/LRS)^2 + 1/(4*LRS^2) ] Notice how similar this is to the dispersion relation for barotropic waves and for the Cushman Roisin solution (absent the part where the Cushman Roisin solution has w going to infinity). Graphing w in wave-vector space, using coordinates k, l, and m*Hzs/LRS, contours of w are spheres. w has a finite maximum value along the k axis. All cross sections that pass through the k axis are identical; all that are parallel to the k axis are similar - hence the behavior of group velocity and phase speed in any such plane projected onto x,y,z coordinates (but with scaling z according to Hzs and LRS)...
128881. Patrick 027 at 16:20 PM on 13 February 2009
        Arctic sea ice melt - natural or man-made?
        Now what I would like to know more about is how Rossby waves propagate up into (or down from) the stratosphere, and also why the stratospheric protion of synoptic-scale waves tilt as they do... And also, if the tilt of growing baroclinic waves tends to be concentrated near the surface (in x,y,z coords) because of the IPV gradient within the troposphere, because the basic state temperature gradient and basic state vertical wind shear are strongest near the surface, or both, ... As noted before, I expect the general tendency for a growing Rossby wave from either baroclinic or barotropic instability is for the group velocity to be away from the basic-state IPV gradient reversal. Does that group velocity reverse in the stratosphere, if there is any in the stratosphere? (Actually, considering the basic state IPV gradient within the troposphere, and the circulation patterns in a growing wave, the axes of IPV anomalies within the troposphere should slope in the opposite direction as the pressure axes - they roughly coincide with IPV anomalies of the same sign at the tropopause but slope with the temperature axes and may be close to 180 deg out of phase with the surface IPV anomalies (due to the surface potential temperature gradient) near the surface. Thus, the IPV anomaly at the surface and it's wind fields must dominate over the tropospheric IPV anomalies and their wind fields in the lower troposphere (in particular, around and below the critical level) in order for the structure of the wave to be as it typically is. PS it's interesting to consider what may happen along a storm track that is tilted horizontally - so that the basic state IPV gradient within the troposphere has a reduced component parallel to those at the surface and at the tropopause... perhaps it could even be possible to have an elevated IPV gradient reversal... ---------------------- But before going further into those issues: I derived the dispersion relation for the vertically-propagating planetary waves (in this case, Rossby waves with IPV gradient due just to beta) described in Holton, p.412-414: w = beta*k / [ k^2 + l^2 + [(m*Hs)^2 + 1/4]/LRS^2 ] Where LRS = N*Hzs/f0 where f0 is a representative f for a beta-plane, N is the buoyancy frequency (proportional to sqrt(S) at any given p) and Hzs is the "scale height" - this is not the vertical scale of a phenomenon or of the atmosphere as a whole or a layer of the atmosphere, but the vertical distance (in z) over which the density (and pressure) decreases exponentially by a factor e (e off the top of my head is ~= 2.718 ...?) - Hzs is treated as a constant here, which is fine since Holton was using a log-pressure vertical coordinate (not actually z but an approximation of z). Hzs is a function of temperature and actually decreases a bit with height within the troposphere. More coming...
128882. Patrick 027 at 15:31 PM on 13 February 2009
        Arctic sea ice melt - natural or man-made?
        A couple other points: Revisiting topographically-forced Rossby waves: Topographic Rossby waves propagate due to variation in PV that are due to topography (which is an IPV gradient at the surface when the air (or water if discussing sea floor topography) is stratified (potential temperature increasing with height - in the ocean, potential density increasing with depth). Topographically forced waves occur when air flows over varying topography. Stretching and compressing air columns while conserving IPV requires changes in AV. When westerly flow goes over a mountain range, the vertical compression causes it to flow somewhat equatorward. Then, because of variation in f with latitude, RV changes as it flows equatorward, so that it turns back the other way. Etc... --------- I've mentioned Kelvin waves a few times but have never really explained them. Like inertio-gravity waves, and unlike Rossby waves, Kelvin waves are fundamentally ageostrophic. Kelvin waves are essentially inertio-gravity waves that are modified by a lateral boundary. 'In the open', the trajectories of inertio-gravity waves are ellipses - alternating pressure pushes the air back and forth (causing alternating pressure, hence the wave propagates) while the coriolis effect deflects the air or water sideways. For the simplest example of a Kelvin wave, consider a gravity wave in water of constant depth propagating along a vertical boundary (imagine a sharp dropoff into the water at the coastline) that is a straight line. As the pressure variations of the wave (corresponding to varying water height) accelerate the water in directions parallel to the boundary, the coriolis effect turns the water toward and away from the boundary. But the water can't actually move into or out of the boundary to balance water motion toward or away from the boundary at some distance. Thus water is removed or piled into the space near the boundary depending on the phase of the wave. This produces a pressure gradient that balances the coriolis effect, so that the water is only accelerated back-and-forth, not sideways. A steady waveform that can result is a Kelvin wave, whose amplitude decays exponentially with distance from the boundary - for the shallow-water approximation, where wavelength is much longer than fluid depth, it decays at a rate proportional to f/c, where c = sqrt(g*h), where h is the fluid depth, and c is the phase speed of the wave - see Cushman Roisin p.79-81. The 'shallow-water' Kelvin wave has the same dispersion relation as the shallow-water gravity wave: c = sqrt(g*h) has no dependence on wavelength, so it is nondispersive. (I don't know about intermediate or deep water Kelvin waves (wavelengths shorter than fluid depth), but would guess that they are dispersive, as are deep water gravity waves.) The Kelvin wave can only propagate in one direction - with the boundary to it's right (facing the direction of propagation) in the Northern hemisphere (f>0), to the left in the Southern hemisphere (f<0). (A solution where the Kelvin wave propagates in the opposite direction does exist, with the amplitude increasing exponentially with distance from the boundary also exists mathematically, but obviously that can't go on indefinitely - such a situation can exist if there is another boundary; from the other boundary, the solution appears as before, with the amplitude decreasing away from the boundary and the propagation with the boundary to the right in the Northern Hemisphere, etc.) Complexities - a lateral boundary with finite slope, curvature of the coastline - will modify the resulting behavior, although if the wavelength is short compared to the curvature, and/or long compared to coastline texture and the extent of the sloping boundary (continental shelf and slope, etc.), then the behavior shouldn't be modified too much, I'd expect. Equatorial Kelvin waves occur because of the reversal of the sign of f across the equator. If an inertio-gravity wave crossed the equator (at the equator it could only be a gravity wave, except for large scale non-zero RV), the elliptical trajectories on each side would run into each other. A Kelvin wave can propagate eastward along the equator that decays in amplitude away from the equator; the northern and southern halfs rest against each other so that the equator acts like the lateral boundary. The water motion is back-and-forth parallel to lines of latitude. Equatorial Kelvin waves can also occur in the atmosphere. More generally, there are no top-to-bottom boundaries in the atmosphere, but topography can produce partial boundaries, and can form complete boundaries for relatively cold air that can't be lifted over them with the forces that exist at a particular moment. Internal (baroclinic) equatorial Kelvin waves occur in the atmosphere that propagate vertically as well as horizontally and are of fundamental importance in driving the QBO (As mentioned somewhere above).
128883. Patrick 027 at 12:26 PM on 13 February 2009
        Arctic sea ice melt - natural or man-made?
        various add-ons: Barotropic analogue to Baroclinic instability: Cushman Roisin, p.103 to 106, examines the case of a band of constant shear (constant RV) of width 2*L, between expanses of zero shear, zero RV. The beta effect was not considered in the example. Cushman Roisin finds a short-wave cutoff; only wavelengths longer than about 9.829*L are unstable and can grow. This is somewhat analogous to considering baroclinic instability with two opposing IPV gradients at two vertical levels; in this case, there are two sharp discontinuities in RV surrounded by regions of constant RV. At the discontinuity, the RV gradient is infinite. But the change in RV is finite, so finite displacements result in RV anomalies of finite value, which can and will propagate as Rossby waves (It doesn't seem like this example included any divergence effects, but this description can be generalized to what would happen at a sharp discontinuity in IPV, or a situation that would approximate that scenario: a variation in IPV over a space considerably smaller than the wavelengths being considered). The dispersion relationship of such Rossby waves could be a bit different than those of waves in a constant IPV gradient. I wonder if the short-wave cutoff would be eliminated if RV varied continuously (as the short-wave cutoff doesn't occur in the Sanders' analytic model in which there is some nonzero IPV gradient at most or all levels)? In this example, Cushman-Roisin does not find a long-wave cutoff to instability. But a long-wave cutoff does occur in the two-level IPV gradient baroclinic case. I've thought about it but I'm not sure why the difference is there (as the wavelength gets longer, a point is reached where the wind field already extends across the reversal (or to the other IPV gradient) quite a bit and further increases won't enhance the interaction across the distance much more. Perhaps the difference is that maybe propagation speed is affected differently for barotropic waves along an IPV discontinuity than for waves along a vertical level of IPV gradient as the wavelength increases...) When there is a wave along a sharp discontinuity in IPV, then when the amplitude gets large (particularly relative to the wavelength), then the IPV anomalies of opposite signs are not centered on the same line. The situation is equivalent to IPV anomalies that are aligned, along with a change in the basic state that involves spreading out the IPV gradient. ------- When there is an IPV gradient outside the region of instability, as mentioned above, the phase tilts of the growing waves imply group velocity away from the reversal of the IPV gradient. This suggests wave energy is removed from the source of the waves, perhaps reducing the growth rates. This could be modified, in particular reduced, if there is a reflecting boundary (PS what about interference patterns?), if the IPV gradient decreases past some distance from the reversal (so that phase speed decreases relative to the air) or if the wind speed changes in a particular way, etc...
128884. Patrick 027 at 06:28 AM on 13 February 2009
        Arctic sea ice melt - natural or man-made?
        Correction: Vertical motion relative to z (geometric vertical coordinate) must go to zero approaching a flat surface (that doesn't move - motions of the oceanic surface are not appreciable to mesoscale and larger atmospheric motions). Vertical motion must be proportional to horizontal motion and to slope along a sloping surface - in other words, averaging over smaller-scale turbulence, the motion approaches being parallel to the surface close to the surface. In pressure coordinates (p), there can be vertical motion at a flat surface as well as any other surface - this corresponds to changing surface pressure. Without diabatic processes, isentropic surfaces are material surfaces and thus cannot actually be pulled out of or pushed into the surface, although their intersections with the surface can be moved along the surface...
128885. Patrick 027 at 15:44 PM on 12 February 2009
        Arctic sea ice melt - natural or man-made?
        General tendencies, typical dimensions of intensifying baroclinic waves: Wallace and Hobbs, p.435: Critical level near 700 mb; at that level, the pressure and temperature waves are ~ 1/4 wavelength out of phase, with warm air 1/4 wavelength east of the pressure trough when the temperature gradient is equatorward (which makes sense given the temperature advection pattern by the winds of the pressure pattern; above and below, air flow through the wave pulls the temperature wave into different phase relationships with the pressure wave, while vertical motion (largest at intermediate vertical levels) modifies the resulting temperature distribution, reducing the growth of the temperature wave amplitude overall but converting potential energy to kinetic energy in the process so that the winds can grow the temperature wave even faster... Again, see comments 76 and 77 at: http://www.skepticalscience.com/volcanoes-and-global-warming.htm ). Warm air is closer to low pressure below the critical level and closer to the pressure ridge above; the temperature distribution itself requires that the pressure wave tilts toward the west with height (when the basic state temperature gradient is equatorward). The tilt is not even at all levels: from Wallace and Hobbs, p.436: the displacement with height of the pressure pattern is about 1/4 wavelength between the surface and 500 mb, and 1/8 wavelength between 500 mb and 250 mb (actually, the simplest interpolation suggests a constant tilt from the surface to 250 mb in pressure coordinates p, but in geometric height z, the tilt must then be decreasing with height, since p decreases roughly exponentially with height in terms of z (exactly exponential for isothermal conditions, but it decreases faster through colder air)... Anyway, diagrams on p.435 of Wallace and Hobbs and p.149 and 163 of Holton show the tilt decrease to zero near the tropopause, and in Holton, the tilt then reverses going into the stratosphere. In Holton p.149, the axes (crests, troughs) of the pressure wave and temperature wave are shown intersecting near the tropopause, so that the low pressure coincides with the cold air and the high pressure coincides the warm air. Above that level, the warm air is ahead (east) of the high pressure, but only slightly, and at the tropopause, the temperature wave reverses nearly abrubtly (mathematically, the amplitude goes to zero and then negative without much horizontal displacement in between). This corresponds to higher S at the low pressure and reduced S at the pressure ridge near the tropopause (but the stratospheric air in general still has higher S than the troposphere). The same happens with the cold air and pressure trough, except that in the diagram of Holton p.149, the reversal of the temperature wave happens as the low pressure and cold air axes intersect, so that the coldest air never gets ahead of the the lowest pressure of the wave, because it becomes the warmest air again as they cross at the tropopause. The main reason for the difference appears to be that the tropopause is lower in the trough than in the ridge. (Note that a lowering of the tropopause tends to correspond to a cyclonic IPV anomaly). These diagrams perhaps shouldn't be taken too literally for those details... But it is true that the the tropopause is lower in the upper level trough and higher in the upper level ridge. Vertical motion can't abrubtly go to zero at some level; it has to approach zero gradually. Vertically motion in a growing wave is mostly thermally direct (warmer air rising, colder air sinking, available potential energy converted to kinetic energy) in the troposphere, but the vertical motion in the stratosphere forces the colder air up and the warmer air down. According to Wallace and Hobbs p.436, the vertical motion itself is dominant in conrolling the the temperature wave; the vertical motion adiabatically warms and cools the air by bringing isentropes to different pressure levels. This makes sense given the increase in stability going into the stratosphere (the effect of vertical motion on temperature is proportional to stability S). It also makes sense given that generally the basic state temperature gradient decreases going upward to the tropopause, and then is relatively weak in the lower stratosphere (except in winter subpolar latitudes, where it is the same direction and sizable, and maybe in parts of the summer hemisphere where it is reversed and sizable at some levels and latitudes). Thus, in the lower stratosphere, kinetic energy is converted back to potential energy. But is this a drag on growth or does the energy spring back at some point? The near alignment of the temperature and pressure axes in the stratosphere are such that in the lower stratosphere, there are cold-core highs and warm-core lows, which thus decrease in strength with height. For the wavelengths of baroclinic waves associated with such transient extratropical cyclones and anticyclones (synoptic scale systems), the waves thus decrease in amplitude going higher into the stratosphere; at higher levels, the larger-scale (planetary-scale) features remain while the synoptic scale features are not apparent. But this doesn't explain why the low pressure and high pressure should tilt east OVER the the temperature wave axes - that seems to violate hydrostatic balance. Maybe there was an error in that diagram? Would this be reconciled by looking at the mesoscale structure (because much of the vertical motion (especially upward motion associated with precipitation) and horizontal temperature gradients being concentrated into/near frontal zones (Wallace and Hobbs p.436), with associated jets - ps at least in part because thermally-direct vertical motion tends to reduce an increase in horizontal temperature gradients, the temperature gradients become sharpest near the surface and also somewhat around the tropopause level (but especially near the surface, I think) - when a front is developing, vertical motion tends to occur where rising motion is on the warm side and sinking motion on the cold side. But the vertical motion has to go to zero at the surface and falls to lower values going toward the tropopause and stratosphere, so there is convergence over the cold air and under the warm air. This allows intensification of the thermal gradient at the surface under the warm air and at upper levels over the cold air. Notice this suggests a general sloping of the frontal zone toward the colder side with increasing height; this is how fronts slope but that might actually not be the real reason?... fronts are more complicated than that...)?
128886. Patrick 027 at 12:56 PM on 12 February 2009
        Arctic sea ice melt - natural or man-made?
        "??It might be the case, though, that the portion of the wave in between the reversal and the critical level depends on the wave on the other side of the critical level to interact with the wave across the reversal in order for the whole pattern to grow in strength.??" - this refers to the IPV pattern and not to the winds; the winds induced by the surface IPV wave extend through the layer beneath the critical level and a bit above it as well. ---------- Bluestein p.115 graph of baroclinic instability (Sanders model): 2b. instability is larger at larger TGRD. (PS whether TGRD is larger or smaller refers to the horizontal temperature gradient at a given vertical level, such as the surface, and not to variations in height, or to variations in the variation with height). Bluestein p.116: including frictional effects, one could find a short-wave cutoff and the wavelength of maximum instability may be made longer. --------- Bluestein p.47 graph and text (Sanders model) poleward speed of surface low pressure center (high pressure center tends to move equatorward): larger for larger perturbation temperature wave amplitude. larger for smaller wavelength and larger VSP --------- Bluestein p.48 (Sanders model) RATIO: cx/u(500 mb) = eastward speed of pressure centers / eastward wind at 500 mb: 1. largest for a wavelength which is longer at higher TGRD 2. larger at larger TGRD. 3. small at shortest wavelengths 4. negative at longer wavelengths and lower TGRD. ---(more Sanders:) RATIO: cy/v(500 mb) = northward speed of pressure center / northward wind at 500 mb: Larger for larger VSP and longer wavelengths. (For growing waves, surface high pressure centers move equatorward and so does the 500 mb flow at that point in the wave). ---(more Sanders:) There is a maximum wavelength for which the surface low pressure motion is to the right of 500 mb flow (and for which surface high pressures move to the left of the 500 mb flow, I think): 1. longer with larger TGRD; 2. dependence on VSP varies with TGRD: at higher TGRD, wavelength is longest for smaller VSP, at middel TGRD, for middle VSP, for small TGRD, larger for larger VSP, although VSP doesn't make much difference in that. VSP may have a similar effect on wavelength of max cx/u(500 mb) - it is longer for a VSP value that is higher at lower TGRD, lower for a higher TGRD, etc... ------------- Bluestein is not all about an idealized model; there is much information about observed patterns and the complexities of their mechanisms: Bluestein p. 116 - wavelength of 500 mb flow in Northern Hemisphere is shorter in summer than in winter, which makes sense given reduced S in summer. - Also, TGRD is larger in winter. In summer, the strong westerly winds are displaced poleward. --- p.117-118 - diffluent (streamlines diverge, winds slow down) vs confluent (streamlines converge, winds speed up) troughs (at intermediate heights in the atmosphere): Midlatitude cyclones seem more likely to intensify (at least in a "conventional" manner) when under diffluent troughs than troughs which are niether confluent nor diffluent and are less likely to intensify under confluent troughs. From elsewhere in Bluestein: the RV advection pattern suggests diffluent troughs should tend to 'dig' equatoward while confluent troughs should tend to 'lift' poleward. --- p.118-119 - horizontally tilted waves (positively tilted waves tilt to the east going poleward (SW to NE in Northern hemisphere); negatively titled waves are oppositely tilted): ..."1977 Glickman et al." found evidence that for upper level troughs, negatively tilted troughs are more likely than positively tilted troughs to occur with "convective activity" - this could be because of "stronger vertical circulation and lower static stability." --- p.199-126: Explosive cyclogenesis - most likely in the cold season over the ocean, "downstream from mobile, diffluent, upper-level troughs, within or poleward of the maximum westerly current, and near the strongest sea-surface temperature gradients such as the northern edge of the Gulf Stream." (and the Kuroshio current) The thermal inertia of the ocean can reduce transient horizontal temperature gradients in the air near the surface that are produced by air currents (p.39), but sea-surface temperature contrasts can act to create thermal gradients in the air above. Cold air from continents in winter moving over the ocean can result in low S (thus, higher VSP) near the surface, increasing instability for shorter wavelengths. The higher winds- more diabatic heating from ocean - high winds feedback (p.19,p.122: ""air-sea interaction" instablity proposed by Emanuel and Rotunno") can play a role. This mechanism is also implicated in tropical cyclone development, although sensible heating may be more important and latent heating less important for explosive midlatitude cyclones than for tropical cyclones. In satellite images, many explosive midlatitude cyclones do appear to have eyes (p.122). One (case?) study of explosive cyclogenesis (Boyle and Bosart) found cold and warm temperature advection values at higher levels in the atmosphere that were unusually large, due to a great lowering of the tropopause ... **more on that on p.123-125. **See also seclusion verses occlusion, p.125-126. --- p.126-127: polar lows / instant occlusions p.127-130: dryline-front intersection low, thermal low, subtropical high
128887. Patrick 027 at 15:42 PM on 11 February 2009
        Arctic sea ice melt - natural or man-made?
        "2. or to have the wind shear be different from the stated tendency - which might occur if one has a horizontal maximum of, for example, anticyclonic vorticity, corresponding with a horizontal maximum of S;" That's for barotropic instability - and I'm not sure this could allow for growth without a critical level - I'm guessing it won't since I've read that critical levels are a requirement for growth - if not, then that was just a generalization that doesn't apply to all situations...
128888. Patrick 027 at 15:37 PM on 11 February 2009
        Arctic sea ice melt - natural or man-made?
        Baroclinic Instability: More: Bluestein describes "Sanders' Analytic Model", which is an idealized checkerboard pattern of baroclinic waves. Considering IPV gradients at two levels (such as the surface (due to the temperature gradient) and the tropopause), Bluestein suggests a range of wavelengths that can intensify by baroclinic instability, with both a long-wave and shortwave cutoff. The whole range and it's cutoffs shifts to longer wavelengths with increasing basic-state vertical wind shear, increasing stability S, decreasing AV and increasing vertical distance H between the levels (Bluestein doesn't explicitly mention those last two points) (*see comment 396*). AV and S have opposite effects; one can reason that decreasing AV/sqrt(S) tends to lengthen the wavelengths of the unstable range. At any given pressure level, sqrt(S) is proportional to N. Note the relationship to the Rossby radius of deformation. However, there is some IPV gradient within the troposphere itself. Using the Sanders' Analytic Model: (In the following, TGRD = basic state horizontal temperature gradient, which is proportional to the basic state vertical wind shear * f (thus, f being generally the largest component of AV, AV is involved in that relationship); VSP = Vorticity-stability parameter, which is in some way proportional to AV/S and larger for larger AV/S values, although I'm not quite sure what the exact proportionality is (Bluestein p.38-39,46) Bluestein p.115 states that while there is a longwave cutoff - which would not exist if there were no beta effect (**question - what about basic state RV,S gradients?) (although I'd thinkthere would still be some finite wavelength of maximum instability)-, there is no actual shortwave cutoff for baroclinic instability, although growth rates approach zero going toward zero wavelength - of course, at some point, the wavelengths are too short for quasigeostrophic approximations to work. Bluestein p.115 graph of baroclinic instability, as measured by deepening rates of surface low pressure centers, for a set amplitude of the temperature wave: 1. largest at some wavelength, .a. that is longer at larger TGRD (but less sensitive to TGRD at larger TGRD), .b. and is longer for smaller VSP (but not so sensitive to VSP at low TGRD at low VSP) 2. larger for larger VSP (and therefore larger AV/S), especially at longer wavelengths* (whereas one might have expected larger VSP to have larger effects at shorter wavelengths?) 3. .a. longwave cuttoff is longer at larger TGRD. .b. AT larger TGRD, longwave cutoff becomes more sensitive to VSP (in particular at higher VSP). .c. longwave cutoff longer for higher VSP (a bit surprising - this is the opposite of what would be expected from the two-level description) Some of these things broadly agree with expectations based on the effects of IPV gradients at two levels, but some, especially 3c., does not. ?? Some part of the difference might perhaps be due to having a comparison based on a set temperature wave amplitudes, as opposed to a set pressure wave amplitude - although they should tend to be proportional in at least the early stages of growth for a given wavelength and vertical structure (tilt); different wavelengths may have different vertical structures... ?? But also, some of the difference could be due to the nonzero IPV gradient within the troposphere. This is partly due to basic state variations in AV (for the Sanders model, if I'm not mistaken, this is all from beta (variation in f), as there is no basic state RV). It is also partly due to the basic state variation in S within the troposphere, which, in the model and also generally in reality, increases poleward (which goes hand-in-hand with the equatorward TGRD decreasing in strength with height. In fact, in the Sanders model it goes to zero at the tropopause and reverses above it. In summer and in the subtropics in winter, the temperature gradient does reverse across the tropopause, although not so at higher latitudes in winter. Because of this, the IPV gradient reversal occurs generally at the surface, so short-wavelength baroclinic waves at the surface whose induced wind fields do not penetrate much to the tropopause are still able to reach across an IPV gradient reversal. More Sanders' Analytic model results: motion of surface pressure centers (note that in this model, there is no basic state wind at the surface): p.46 east-west motion: 1 .a. There is a wavelength of maximum eastward surface low propagation - .b. - which is longer for higher basic state T gradient (TGRD). 2. westward only at longer wavelengths and lower TGRD. 3. .a. wavelength of maximum eastward motion may be a bit longer for lower VSP. .b. But westward speeds where they occur are also a bit greater for lower VSP, in particular for low TGRD. 4. Small eastward speeds for short wavelengths 5. larger eastward speeds for larger TGRD. It makes sense that larger TGRD, which corresponds to larger vertical wind shear and higher westerly winds at a given height above the surface, should correspond to faster eastward motion of the waves. That eastward motion is slower at wavelength extremes (and negative for the longest wavelengths) can be understood as a consequence of 1. dominance of the beta effect (planetary vorticity advection dominating over RV advection, where in this model, there is no basic state RV) at larger wavelengths (**or more generally, Rossby waves with larger wavelengths (which have greater vertical penetration***) have faster phase speeds and the basic state poleward IPV gradient (except at the surface***) supports Rossby wave self-propagation to the west). 2. Short wavelength baroclinic waves in this model are concentrated at the surface and they don't interact as much with the strongest westerly winds at higher levels (more generally, short wavelength features can occur at all levels, but they generally need to induce wind at the surface to initiate a growing wave by baroclinic instability, given typical conditions. Smaller VSP would decrease even more the vertical penetration of winds induced by small-wavelength features, so that the wavelength of fastest eastward motion shifts away from shorter waves, thus 3a. makes sense. Recall that baroclinic and barotropic instability both require a critical level where the air is not moving relative to the waves. I think this can be understood as a consequence of how the phase-locking mechanism works. A reversal of the IPV gradient in either the horizontal or vertical tends to come with a basic state horizontal or vertical wind shear, respectively, that is in the opposite sense of the difference in self-propagation directions of the Rossby waves on either side of the reversal. The only way (so far as I can tell) to have pattern without a critical level is 1. to construct a pattern that propagates through the air in the same direction on both sides of the reversal is to use a pattern that is not aligned for growth, but instead for at least some decay (in which case, the pattern may shift until it is so aligned, at which point it then have a critical level) - and for one side to dominate in controlling propagation (either by having a larger amplitude or having a larger IPV gradient, etc.), 2. or to have the wind shear be different from the stated tendency - which might occur if one has a horizontal maximum of, for example, anticyclonic vorticity, corresponding with a horizontal maximum of S; however, the anticyclonic vorticity must then grow in strength vertically away from that level, and eventually either the variation in S has to change or else a boundary is reached where there is a surface IPV gradient, etc...*** For typical conditions, the IPV gradient reversal for baroclinic instability is at the surface, but the critical level is typically around 700 mb (in the the troposphere, below the middle of the troposphere (if the tropopause height ~ 250 mb; average sea level pressure is just over 1000 mb), but above the surface). It is not necessary for the critical level to coincide with the reversal. ??It might be the case, though, that the portion of the wave in between the reversal and the critical level depends on the wave on the other side of the critical level to interact with the wave across the reversal in order for the whole pattern to grow in strength.??
128889. Patrick 027 at 11:11 AM on 11 February 2009
        Arctic sea ice melt - natural or man-made?
        "Consensus is flat-earth proof" Subtle irony: there was never a scientific consensus that the world was flat (was it Eratosthenes? who calculated the size of the Earth somewhere around 500 BC, give or take? - but of course for a long time the average peasant farmer would not have been aware of this (the public school system wasn't that great)) - (I wonder what the ancient Chinese and/or Mayans thought on the matter?).
128890. Quietman at 09:29 AM on 11 February 2009
        It's not bad
        High Carbon Dioxide Boosts Plant Respiration, Potentially Affecting Climate And Crops ScienceDaily (Feb. 10, 2009) "The leaves of soybeans grown at the elevated carbon dioxide (CO2) levels predicted for the year 2050 respire more than those grown under current atmospheric conditions, researchers report, a finding that will help fine-tune climate models and could point to increased crop yields as CO2 levels rise."
128891. Quietman at 07:52 AM on 11 February 2009
        Is Antarctic ice melting or growing?
        For chris This is from a post at Live Science from someone that appears to know a little more about the Laws of Thermodynamics: ["First off, the word "Law" is misleading. In science, a Law is really just a theory for which no exceptions have been found. The so-called "Laws" of Thermodynamics are not absolute. They remained undefeated for many years, but then, one-by-one, exceptions were found. They keep the name of Law in common parlance, however. First Law of Thermodynamics: The matter/energy in a CLOSED SYSTEM is USUALLY conserved. Matter/Energy is neither created nor destroyed, only changed in form. Not really a Law anymore, as there are many exceptions to it that have been found, like the Cassimir Effect. This law only applies to a CLOSED SYSTEM, neither the Earth, nor the Universe (by current Quantum Theory) is closed. Case closed. Second Law of Thermodynamics: The TOTAL entropy (Entropy = Heat Energy/Absolute Temperature, NOT chaos) of a CLOSED SYSTEM will TEND to increase until equilibrium is reached. Alternately: A system in which a thermodynamic process is occurring will increase the NET entropy of the Universe. TOTAL entropy means that there may be areas of entropic imbalance, i.e. areas of high entropy, and areas of low entropy. Again, this only applies to a CLOSED system. The Sun provides the Earth with fresh heat energy. The Earth dissipates entropic heat to space, therefore it is NOT closed (the net entropy of the Earth may remain constant while the net entropy of the universe increases). Exceptions have been found, therefore the word USUALLY is thrown in. Finally, entropy only increases until equilibrium is reached (and all THERMODYNAMIC processes cease.) Third Law of Thermodynamics: As a system approaches absolute zero, all processes cease and the entropy of the system approaches a minimum value. I really don't see what relevance this has AT ALL. This law also has exceptions. The atoms in certain crystal lattices do not have a unique ground state by time-reversal symmetry, and therefore cannot reach zero entropy."]
128892. Mizimi at 04:54 AM on 11 February 2009
        Global warming stopped in 1998, 1995, 2002, 2007, 2010, ????
        #35 https://www.llnl.gov/str/Durham.html gives a brief outline of methane hydrate properties which are totally different to methane gas - which I suspect you are confusing it with.
128893. Quietman at 04:13 AM on 11 February 2009
        There is no consensus
        Risky Re: "Everybody, from all sides of the argument - please take it seriously." We take this very seriously. That is exactly why we argue about it. I see the IPCC wasting valuable time and resources looking to cure an illness that does not exist when they should be researching to find the true root cause.
128894. Risky at 22:22 PM on 10 February 2009
        There is no consensus
        Discussion between Professor Ove Hoegh-Guldberg and Andrew Bolt: http://www.abc.net.au/austory/ Professor Hoegh-Guldberg is one of the early scientists to relate episodes of coral bleaching to climate change, Andrew Bolt is a conservative commentator and climate "skeptic" here in Australia. Interesting discussion, no clear winner. My one observation - Bolt finally fronts an actual climate scientist (after years of all kinds of accusations against climate scientists), and blames the media for exaggerating the threat. Maybe he was being polite. On another issue: Here in the south-east of Australia, we have recently had a record heat wave, followed by the hottest day since records began (in 1855) within the space of a week. This created firestorm conditions that have never before been recorded. In one day, over 200 people died (maybe 300), by far the worst fire disaster in Australian history. The fires are still burning. Before you all howl 'this is weather, not climate' or 'does not belong in this thread', I mention these things for a reason. If the climate scientist's predictions are correct, we will have more days like this - and worse. This is not just some cosy little academic debate, with a vote at the end to determine who is the champion debater. The consequences of getting it wrong are huge and tragic. Everybody, from all sides of the argument - please take it seriously.
128895. Philippe Chantreau at 17:45 PM on 10 February 2009
        Arctic sea ice melt - natural or man-made?
        Quietman, you're the one interpreting the number of citations that way. Among researchers, nobody cares about your interpretation. If a paper has a bunch a cites refuting it, then that makes it relevant too. Why do you think that Elsevier and everyone else provide links to cites and individual citing articles? Get over yourself. Your interpretation is not everyone's interpretation, especially not among those who actually work and research a field. I no longer think that you deserve to be called a skeptic. You accuse RC of political or other biases yet you have no problem throwing around links to Morano's pathetic bull***t. You linked Hays' letter but failed to mention how his very non scientfic objections were thoroughly addressed by the author he criticized. Oh, sorry, I forgot, you don't read RC. That limits your reading to critics of RC posts from other sources and restricts your access to responses that would be on RC. But it all fits with your idea of "skepticism" and "balanced view", I'm sure. You keep on citing stuff that does not support what you say it does and when called on that by Chris, you go on accusing him of bias or "not liking the authors" without ANY basis for the accusation. You give credence to far fetched ideas with a scant or non existent publication record while holding doubts on published ideas that have succesfully cleared authentic scientific scrutiny. When confronted with that, you resort to the tried and true, whiny excuse of creationists, i.e. "scientific journals are biased against our ideas so we can't publish." Pretty sad. You're not showing any true skepticism. By the way, I recall you mentioning scientific evidence of a coming ice age. Care to show the references? Are the majority of glaciers around the world growing? I also recall you talking about the weather and how cold it was wherever. Well, in Australia, it's mighty hot, and in China, Chile, Argentina, it's very dry and hot, and where I am we had extreme winter heat by the coast and a miserable snowpack. We've had spring skiing conditions in January, with warmer temps at 7000 ft than at 100ft. That's my weather report, local and other.
128896. Quietman at 09:43 AM on 10 February 2009
        Arctic sea ice melt - natural or man-made?
        Patrick Yes, that's my point. Just the number of citations makes it appear to be endorsement while in fact they all could be arguments against the paper. I don't think that the number of citations is relavent for that reason.
128897. Quietman at 07:52 AM on 10 February 2009
        It's the sun
        piszkace There are a couple of factors involved. GHG is one. The sun another and plate tectonics another. The sun provides most of the heat and the earth, via plate tectonics both provides additional heat and determines how it is distributed, ie. it controls ocean patterns and oscillations which in turn control the air circulation and weather patterns. GHGs maintain the heat but can not cause or provide any heat. This is why the term "global warming" is incorrect. We have temperature anomalies appearing in several places on the planet, most notably is the west antarctic penn. and northern Greenland. There are others but these two shine out because of the ice melt. They are both (as well as others) tectonically driven (what we term as "root cause" in engineering. (Engineers look for root cause because fixing symptoms gets you nowhere, it's a bit like taking aspirin for a flu - you stop the fever but you still are sick).
128898. Quietman at 07:39 AM on 10 February 2009
        There is no consensus
        ps You left out that Meteorologists are about evenly divided on the cause. I think it was a 47/53 percentage split. Engineers disagree because they realize that the laws of thermodynamics are not actually applicable to the earth or living things (something the greens and creationists don't seem to understand). Those scientists behind AGW are actually not "climatologists" (the number of people with PhDs in this field number only a couple hundred and Hansen is not one of them, Fairbridge for example taught climatology and he was a "denier").
128899. Quietman at 07:30 AM on 10 February 2009
        There is no consensus
        Re: "The greatest doubt is held by petroleum geologists (what a surprise)." They are also among the best qualified to know what is really causing this problem, no surprise here, after all it is a tectonic issue.
128900. Quietman at 07:22 AM on 10 February 2009
        Volcanoes emit more CO2 than humans
        The Keweenaw rift That sounds logical enough. I thought that you were talking about a recent event when you first said "a failed rift". It does not seem to have failed, just old and later compressed. My cousin has a degree in geology (not a PhD) and showed me some of the features upstate New York some years ago. Where he is now (near Albany) has Devonian rock all over, covered with fossils. Interesting stuff.

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