Recent Comments

Prev  2598  2599  2600  2601  2602  2603  2604  2605  2606  2607  2608  2609  2610  2611  2612  2613  Next

Comments 130251 to 130300:

130251. chris at 05:43 AM on 23 January 2009
        Christmas cartoon on melting North Pole
        re #16: Not really Quietman, the essential conclusions of the original Mann et al. palaeoproxy analyses in relation to the anomalous nature of late 20th century and contemporary warming are independent of whether or not tree ring proxies are used: e.g. M. E. Mann et al. (2008) Proxy-based reconstructions of hemispheric and global surface temperature variations over the past two millennia Proc. Natl. Acad. Sci. 105:13252-13257 In which over 1,200 proxy series were used to assess millenial scale temperature. In fact the data are now rather firmer in relation to our understanding of the anomalous nature of current warming compared to the last 1300 years. The conclusions are prety much the same if the tree ring series are left out, except that they don't extend back to 1700 years into the past (which is possible using tree ring data). And of course tree ring proxies are only used under specific conditions that the tree species and locales are not moisture-limited but are temperature-limited (generally highish latitudes and highish altitudes...
130252. Philippe Chantreau at 04:31 AM on 23 January 2009
        Christmas cartoon on melting North Pole
        Marc Morano is a politician of the worst kind: a PR professional. I don't trust anything he writes. The so-called "growing surge" exists only in his pathetic mind manipulation effort. Morano is scientifically illiterate, so is Inhoffe. If you don't even trust Wikipedia because, in your own words, it is too politicized, why would you give any attention to Morano and Inhoffe, who are about nothing but politics and have not a clue about science? Hansen is entirely justified to denigrate nincompoops who have no idea of what they're talking about and merrily go on accusing him of fraud every time they have a chance.
130253. Quietman at 03:15 AM on 23 January 2009
        Christmas cartoon on melting North Pole
        Philippe My point was if we use the Rainfall/Drought data it contradicts the use in the ol' hockey stick. Ps This is interesting: NASA's James Hansen calls climate skeptics court jesters In the face of this growing surge of scientific research and the increasing number of scientists speaking out, NASA scientist James Hansen wrote this past week that skeptics of a predicted climate catastrophe were engaging in “deceit” and were nothing more than “court jesters.” “The contrarians will be remembered as court jesters. There is no point to joust with court jesters. They will always be present,” Hanson wrote on August 16, 2007.
130254. Quietman at 03:11 AM on 23 January 2009
        Climate sensitivity is low
        Do you mean this paper? HEAT CAPACITY, TIME CONSTANT, AND SENSITIVITY OF EARTH'S CLIMATE SYSTEM by Stephen E. Schwartz
130255. Quietman at 02:17 AM on 23 January 2009
        Volcanoes emit more CO2 than humans
        ps Here is another example from a different scientist. There is an apparent agreement with Fairbridge: Earth's Orbit Creates More Than A Leap Year: Orbital Behaviors Also Drive Climate Changes, Ice Ages ScienceDaily (Feb. 18, 2008) — The Earth's orbital behaviors are responsible for more than just presenting us with a leap year every four years. According to Michael E. Wysession, Ph.D., associate professor of earth and planetary sciences in Arts & Sciences at Washington University in St. Louis, parameters such as planetary gravitational attractions, the Earth's elliptical orbit around the sun and the degree of tilt of our planet's axis with respect to its path around the sun, have implications for climate change and the advent of ice ages.
130256. Patrick 027 at 16:16 PM on 22 January 2009
        Arctic sea ice melt - natural or man-made?
        ... The Cushman-Roisin solution is not intended to be a complete description of such waves (baroclinic planetary or Rossby waves in general) - just to illustrate the basic concept. It might (?) more readily apply to the ocean where density variations are a small percentage of total density.
130257. Mizimi at 05:02 AM on 22 January 2009
        Do cosmic rays cause clouds?
        This thread asks a question - 'do cosmic rays cause clouds?', which somehow has transmogrified into are CR's responsible for global warming. Usoskin stated "Cosmic radiation induced ionisation is not the main source of cloud formation but rather modulates it and the long-term trend results from other processes, which are outside the main focus of this study. So clearly there IS a body of opinion that CR's DO affect (not effect) cloud formation.
130258. FerdiEgb at 23:37 PM on 21 January 2009
        CO2 lags temperature
        Sorry for the (very late) drop by! I was informed about this page by a reference from a recent discussion... No problem with the first statement: During ice ages/interglacials there is a lag of CO2 after temperature changes of 800 +/- 600 years in upgoing parts and several thousands of years during falling years with a sensitivity of about 800 ppmv/°C. This reduces to about 50 years lag for the MWP-LIA transition (again about 8 ppmv/°C) and 1 to a few months around the upgoing trend today (with about 3 ppmv/°C). But a big problem with the second statement: "The CO2 record confirms both the amplifying effect of atmospheric CO2 and how sensitive climate is to change." The amplifying effect of CO2 is difficult to estimate, as most of the time there is an overlap between the upgoing and downgoing trend of temperature and CO2. But there is an interesting exception: the end of the previous warm(er) period: the Eemian. The CO2 levels remained high while the temperature (and methane levels) dropped to a minimum value and ice sheets did grow again to a maximum. The subsequent decrease of 40 ppmv CO2 doesn't show any measurable drop in temperature outside the error margins. The theoretical change with 3°C/2xCO2 should give a drop of 0.4°C, and that is not visible in the ice core record. That means that the 3°C/2xCO2 is probably overblown. See: http://www.ferdinand-engelbeen.be/klimaat/eemian.html A second graph which shows that there is not that much feedback from increased CO2 on temperature, is from the very detailed Epica C ice core. The influence of temperature on CO2 (with lag) is clearly visible, but the influence of CO2 on temperature is clearly... absent. That is remarkable for what is assumed to be responsable for about 40% of the increase in temperature... See: http://www.ferdinand-engelbeen.be/klimaat/klim_img/epica5.gif With thanks to Andre van den Berg who made the graph. Thus the science about the feedback and sensitivity of the climate for CO2 changes is far from settled...
130259. Philippe Chantreau at 16:45 PM on 21 January 2009
        Christmas cartoon on melting North Pole
        OK. I'm aware of that. In temp reconstructions, they are used somewhat differently, as temp proxies. Sjkhayes had a problem with dendro data as temp proxies. I just pointed that there are other proxies.
130260. Wondering Aloud at 08:13 AM on 21 January 2009
        Is Pacific Decadal Oscillation the Smoking Gun?
        Where is this one at? I think I sam a claim that PDO was back into a neutral phase and that the it never really switched for any significant time? When you present global temperature anomaly graphs like the one above who is the source of these graghs? Do the ones you use now look the same as they did a few years ago for the period from 1880 to 1990?
130261. Quietman at 07:55 AM on 21 January 2009
        Christmas cartoon on melting North Pole
        Philippe The tree rings aerve a better indicator of time of drought and times of plentiful rainfall. When there is plenty of moisture they grow faster and sequester more carbon via CO2 intake. In times of drought they can't.
130262. Wondering Aloud at 06:55 AM on 21 January 2009
        Arctic sea ice melt - natural or man-made?
        Patrick 027 I do agree with you in your post 407. That is not only proper it is important, I was just pointing out that just because it is cited doesn't mean it is supporting everything said, or even that it is anything additional. I found that I had to know the citations in great detail to evaluate the paper. I am sure this is why we have to specialize so much.
130263. Patrick 027 at 16:03 PM on 20 January 2009
        Arctic sea ice melt - natural or man-made?
        Of course, other waves (or patterns of linear superpositions of waves) with mj for non-integer j values can exist, but they won't form a steadily-propagating pattern in the horizontal direction - they will interact with the boundaries of the fluid to produce reflected waves, which aren't part of the same pattern, so the pattern evolves. And there is a gap in the m spectrum between m0 and -m0. OTHER THOUGHTS: 7. It occured to me that the IPV distribution at a fluid boundary (as opposed to within the fluid) due to the potential temperature (q) gradient along that surface, might be described in terms of an 'image IPV' (? like an 'image charge' in electrostatics ?) that exists somewhere below the boundary, with the condition that the air doesn't cross the boundary between the real fluid and the image fluid. Along the same lines, the reflection (partial or complete) - if that's what it is - of the RV field of an IPV anomaly, off a boundary, might be due to an image IPV on the other side of the boundary that is a reflection of the IPV anomaly. But the image IPV is seen only from the side of the boundary it doesn't exist in (or else it has different effects where it is placed than from where it can be seen as a reflected image) ... haven't done the math on this idea, yet... 8. A planetary wave, depending on the basic state f variation, is modified by nonzero S but clearly depends on the basic state f gradient. A topographic Rossby wave has an IPV gradient that is due to variation of Hzd (or surface pressure) of the fluid due to bottom topography. (Barotropic Rossby waves with an IPV gradient due to RV variations could be said to be due to the 'topography' of the top of the fluid - which corresponds to variations in pressure on a geopotential (constant z) surface.) In the presense of nonzero S, the bottom topography intersects isentropic surfaces that are horizontal in x,y,z, or typically nearly so in x,y,p coordinates. It could be seen as altering the basic state fluid depth of individual isentropic layers where it intersects them. The IPV gradient could be said to be at the surface. There is thus a similarity between topographic Rossby waves and Rossby waves propagating due to a temperature (and thus potential temperature) gradient along a non-sloping (in x,y,p or perhaps x,y,z) bottom surface. And both should have amplitudes enhanced towards the surface. --------- About surface amplitude enhancement or reduction for topographic or surface q-gradient Rossby waves verses planetary waves, respectively - this is relative to the variation in amplitude with height that may occur because of basic state varyiations, in particular decreasing density. This effect was not covered by the baroclinic Rossby wave description from Cushman-Roisin, but Holton has solutions with constant vertical wavelength in z coordinates which increase in amplitude with height roughly in proportion to the inverse square root of density. Energy per unit mass is proportional to the square of amplitude, and thus given the solution from Holton, is inversely proportional to density. This implies constant energy per unit volume. For constant vertical wavelength with height, this implies constant energy per wavelength. Given the conditions for that solution, I think that Rossby waves with upward group velocity concentrate energy into smaller masses as the energy propagates upward. This is reversable, in the sense that energy per unit mass declines with downward propagating energy (it is not an aspect of an instability or dissipation of the wave).
130264. Patrick 027 at 12:32 PM on 20 January 2009
        Arctic sea ice melt - natural or man-made?
        Various notes: 1. In the expression for Ross, as in the formulae for Rossby radii of deformation, f could be replaced with f_loc if one is using a gradient wind balance instead of a geostrophic balance. 2. "'time step'**" - The secondary circulation (SAAC) obviously starts to occur as soon as MF or TF start to disrupt geostrophic (or gradient wind) balance. Rossby waves and other quasigeostrophic phenomena can be described witht the approximation that SAAC occurs to completion instantaneously (because it is faster than the quasigeostrophic advection that may contribute to MF and TF in a range of spatial and temporal scales). Using a time step where MF and TF occur without SAAC and then allowing SAAC to occur is just a way to illustrate cause and effect. Of course, using many small time steps, as in numerical integration or a computer model, can approximate the process. In reality, if there were a sufficently sudden MF and/or TF, the SAAC would over-react - it would tend to oscillate about a balanced-wind equilibrium. Within a closed space this could involve oscillation through the same conditions; but more generally, the oscillation at the source decays as inertio-gravity waves (or Kelvin waves if the situation calls for it) are radiated outward. Because these waves have some energy, but the resulting balanced state should be the same whether the changes are sharp or gradual, I suspect it must take some additional energy to force a sudden change, which suggests the fluid may tend to resist such change (?). One can see how a gradual change avoids producing significant inertio-gravity or Kelvin waves by using the approximation of many small time steps. A set of such ageostrophic waves are emitted at each time step, but the change at each step is small, so the emitted waves should be small as well. In addition, over many time steps, many sets of waves would be emitted that are not in phase with each other, thus not leading to greater and greater amplitudes over time. Changes that are gradual relative to the period of the ageostrophic waves can thus avoid significant emission of those waves (PS a similar argument can be used in describing why reflection is stronger off a boundary in space when it is sharp relative to wavelength - that may come up if I ever get to Rossby wave refraction.) But it would take some specific conditions to completely avoid emission of such ageostrophic waves - not accounting for those waves is one of the approximations that can be used in studying slower quasigeostrophic processes. 3. The MMC, including adiabatic response to diabatic forcing, is a zonally averaged SAAC. Thus the MMC due to the RVad (due to part of the u'v' of the EP flux**) and the MMC due to qad (which is the v'T' of the EP flux) will be equal, in the same direction. The MMC of a SSW is poleward at and around the level of EP flux convergence, but there is adiabatic warming below poleward, etc, so the RVad would have to 'win out' in that case if RVad were the dominant part of MF. Of course, the other important part of MF (except near the surface) comes from the variation in f, and planetary vorticity (f) advection often dominates over RV advection. The diabatic portion of TF that may occur with an SSW will tend to be, as I understand it, a response to the SSW. The warming of the polar stratosphere drives a diabatic cooling, which causes additional MMC in the same direction as that which occurs as part of the SSW. 4. **Question - Did the analysis of comment 412 imply that, where RV and/or temperature variation contributes to the basic state IPV gradient, that there is some intermediate wavevector for which there is no propagation? This seems odd - but I have to set that aside for now. 5. The three dimensional wave vector = [k,l,m], where m equals 2*pi/(vertical wavelength). m can be given in terms of different units depending on the vertical coordinate being used (z, p, q, etc.). Downward phase propagation occurs with m < 0. 6. The analysis of comment 412 applies to vertical variations in MF. I think a properly-weighted vertically-average of MF could be subtracted from all levels so that the remaining MF is the vertically-varying MF that occurs with a TF (when W and Q are not undefined - that is, when there is some nonzero RVad and qad) and to which comment 412 applies. The vertically-averaged MF would cause some SAAC that tends to produce cold-core lows and warm-core highs (weaker at lower levels). The total vertical scale of the fluid places an upper limit on the vertical scale of any wave or other phenomenon. ------- For example, for planetary waves (specifically, IPV gradient due only to variations in f, with the gradient in the positive y direction) in a fluid with nonzero S, Cushman-Roisin finds the dispersion relation: w = - beta * k / [ k^2 + l^2 + m^2 * f0 / N^2 ] where N is the buoyancy frequency and N^2 is proportional to S for a given p or z, etc, and f0 is a representative f for a beta-plane. The solution was for waves that propagate horizontally but are standing waves in the vertical direction, of the form: 2 * cos(m*z) * cos(k*x + l*y - w*t) But this is the linear superposition of two baroclinic waves of opposite vertical tilts: cos(k*x + l*y + m*z - w*t) and cos(k*x + l*y - m*z - w*t) so the two wave vectors are [k,l,m] and [k,l,-m]. But they have the same w and the same dispersion relationship (which is independent of the sign of m) applies. This is for x,y,z coordinates for a fluid with definite top and bottom boundaries. For total fluid depth Hzd (d for depth, z for the vertical coordinate), there are a set of allowable m values (Because this was for waves that are standing in the vertical direction): m = m0, m1, m2, ... (and also negative m values of the same magnitudes) where m0 ~= N/sqrt(g*Hzd) and for j = 1,2,3 ... mj = j*pi/Hzd Putting these into the dispersion equation, one finds that the m0 wave has the same dispersion relation as a barotropic wave, w = - beta * k / [ k^2 + l^2 + 1/R0^2 ], where R0 is the external Rossby radius of deformation for Hzd, f0, and g, and the mj waves have the dispersion relation: w = - beta * k / [ k^2 + l^2 + 1/Rj^2 ], where Rj is the internal Rossby radius of deformation for Hzj, f0, and N, where Hzj = vertical wavelength / 2*pi = 1/mj. And, R0 is also equal to the internal Rossby radius of deformation for Hz0 = vertical wavelength / 2*pi = 1/m0. This seems to make sense so far. How does the dispersion relationship look when graphed in three dimensions, k, l, and m? The surfaces of constant w form ellipsoids; if the m dimension is scaled by some other factor, they appear as spheres. A cross section parallel to the k,l plane at a nonzero m has the same shape as the graph of w over k,l for the barotropic waves discussed in comment 361; for such a plane at m = +/- m0, the graph is exactly the same. Any cross section taken parallel to the k axis looks similar and can be made to appear the same with stretching or contraction along axes - with one exception: cross sections along the k axis, which pass through the origin where m and l are also 0. The difference there is that w goes to inifinity approaching the origin from negative k values, but all contours of w go through the origin. Other cross sections parallel to the k-axis appear similar at large wavenumbers, but at small wavenumbers, the difference is that there is a finite maximum in w along the k axis at a negative value of k. With some differences for wave vectors with m and l equal to zero, there will thus be similar patterns in group velocity and phase speed within any plane parallel to the x-axis. BUT, for the solutions from Cushman Roisin, m = 0 is not allowed, only +/- m0, m1, m2, ... etc, because these are components of standing waves in the vertical direction, with the waves of m > 0 being produced by the waves of m < 1 and vice-versa upon reflection (with the vorticity wave in phase with incident wave)from the top and bottom boundaries - or that's what I thought. But this is only approximately true for j = 1,2,3, ... and not true m0. The number of vertical wavelengths that can fit into the total fluid depth Hzd for standing waves reflecting in phase must be an integer multiple of 1/2. To a first approximation, the number of vertical wavelengths that fit is equal to j * 1/2, but it is actually somewhat more (the vertical wavelengths are somewhat less) and the difference increases for smaller j values (larger vertical wavelengths). For such standing waves resulting from reflections as just described, the j = 0 wave ought to have an undefined vertical wavelength - essentially an infinite wavelength, with m = 0. But in the dispersion relationship, that would be a barotropic wave with infinite frequency and phase speed in the horizontal direction. Instead, the barotropic Rossby wave has to be reconstructed from the linear superposition of waves with m = m0 and m = -m0. They are in phase at the lower boundary (the surface if in the atmosphere) but they are not in phase at the upper boundary, so the wave is strongest at the surface and decreases in amplitude with height. **This is problematic - it implies warm core lows and cold core highs, the pattern expected for topographic Rossby waves with nonzero S. The pattern expected for planetary Rossby waves (depending only on variation of f) with nonzero S is for amplitude to be reduced near the surface. So I'm not sure about this...**
130265. Quietman at 05:51 AM on 20 January 2009
        Volcanoes emit more CO2 than humans
        Patrick Wikipedia Entry Article A quick web search provides many more links.
130266. Philippe Chantreau at 04:26 AM on 20 January 2009
        Christmas cartoon on melting North Pole
        You can try leaving tree rings out altogether, there are other methods: http://www.geo.lsa.umich.edu/climate/ The latest Mann paper has all data and code available. GISSTEMP code was made available a long time ago.
130267. sjkhayes at 02:55 AM on 20 January 2009
        Christmas cartoon on melting North Pole
        Sear sir or madam: I recently came across the “great hockey stick controversy” and I am trying to find a well argued view of it from those who favour the climate consensus of human induced global warming. I came across your site and while I find it very good in its rebuttals, it does not, it would seem to me, answer what I would call the “ah buts.” That is to say you present good rebuttals, but it seems that the detail of the criticism is not addressed. The background here is that prior to coming across this controversy, I was leaning towards the view that global warming was human induced, but the hockey stick controversy has severely dented this view. So here are the rebuttals and the "ah buts" that I would be very grateful if you to please assist me by adressign the "ah buts" yourself, or pointing me to where they are addressed. ============== Rebuttal 1: The NCR review initiated by the National Academy of sciences in 2006 vindicated Mann’s original 98 hockey stick work, albeit with some reservations. Ah but 1: The NCR panel was biased but even then they agreed with the McKittrick and McIntyre criticism that Mann’s 98 methods produced a hockey stick shape when random red noise was applied to it. I read the report and the graph showing this is in there. Surely this makes a nonsense of Mann’s 98 work. ============== Rebuttal 2: The Hockey stick has been confirmed by other subsequent studies as evidenced by the NCR report. Ah but 2a: Most of the other studies use the same set of contested trees from the south west United States and the polar urals that the NCR panel should said should not be used. If you remove the contested trees, the hockey stick disappears and the Medievel Warm Period and Little Ice Age reappear. Ah but 2B: The confirmation work has all (or mostly) been done by associates of Mann. ============== Rebuttal 3: If you remove the contested trees from the analysis, yes the medieval warm period exists, but the late 20th century is still significantly higher than it was then. Ah but 3: The studies maintaining this splice the instrumental record on to the tree ring record from about 1980 on. If the tree ring record was continued to today, the tree ring proxies would show a fall in temperature. I.E. they would diverge giving us what is called the divergence problem in the debate. ============== Rebuttal 4: Amman and Wahl’s paper from 2006 (or was it 2007) was a key piece of confirmatory evidence. Ah but 4a: The IPCC bent the rules to allow it into the Fourth Assessment report. Ah but 4b: Amman and Wahl refused for three years to release the R2 statistic that would have shown that their study was unreliable. Eventually they came up with a mumbo jumbo justification to say that the R2 statistic was irrelevant. ============== Rebuttal 5: Mann’s 2008 paper has reproduced the hockey stick using 96 different proxies. Ah but 5b: If you take out the contested trees from the south west United States and the proxies from the Tiljander lake whose original authors said were corrupted, then the hockey stick disappears and the Medievel Warm Peirod and Little Ice Age come back. ============== One other point that you might help me to address is to come up with a justification for the reluctance of climate researchers to release their data, method and source code other than “do your own research”. If this could be justified for publicly funded research, even better. Many thanks Shane
        Response: Discussion on the hockey stick is best conducted on the hockey stick page. And yes, that page does need updating considering the latest study on the topic coming out last year (it's on my to-do list).
130268. Mizimi at 02:03 AM on 20 January 2009
        We're heading into an ice age
        QM: have you read this, and if so, any comment? http://www.griffith.edu.au/conference/ics2007/pdf/ICS176.pdf How's the greehouse project?
130269. Mizimi at 01:34 AM on 20 January 2009
        It's not bad
        Millions of years ago, climate conditions were such that plant life grew rapidly on a global scale. CO2 and WV levels were high enough to sustain this growth and during this period much of the FF's we now burn were laid down. Plant life sequestered CO2 and locked it up as FF, thereby reducing the CO2 levels, although at times, 'natural' events such as vulcanic erutions/forest fires would have temporarily offset this sequestration. The end result is that CO2 levels hit (possibly) an all time low of around 200ppm and stayed there. As this level is close to the minimum C3 plants can tolerate, further growth and investment of new habitat were resticted. At this time, only C3 plants existed (fossil records of C4 plants indicate their emergence around 8mya) and C3 plants, in order to prosper, require CO2 levels higher than 200ppm. If the levels fall below this figure, then growth effectively halts as does sequestration. One can argue that the emergence of C4 plants was 'caused' by persistent low levels of CO2 - an adaptation of metabolic process to environmental pressures - and since they are more efficient in their use of CO2,(they had to be) they began to colonise and modify habitats where C3 plants could no longer compete effectively. C4 plants are grasses, and include the cereals. The rise of civilisation was made possible only because of these plants and man's ability to husband them, so we actually owe our existence to low levels of atmospheric CO2. Current concern is directed at enhanced CO2 levels through burning FF's, and the (modelled) effects this may have on climate, and the consequent impact on man's habitat. The current level of around 380ppm, whilst nearly double that during the period C3 plants were dominant, is still towards the lower level of tolerance for them. It can therefore be argued that further increases of CO2 will be beneficial to this class of plants and not detrimental to C4's until levels exceed 1000ppm; in other words, our CO2 emissions are helping C3 plants, and quite possibly helping (in some small way) to offset the losses incurred by de-forestation. Yes, they may be disadvantages to mankind and his preferred lifestyle/habitat from CO2 enhancement, but there are benefits to the biosphere at large.
130270. Patrick 027 at 16:18 PM on 19 January 2009
        Arctic sea ice melt - natural or man-made?
        In a quasigeostrophic approximation: In isobaric coordinates x,y,p: Following the air as it moves: As mentioned in comment 411, the change in vertical wind shear driven by momentum (wind) advection by geostrophic wind shear (Let's call this 'momentum forcing' - MF, in this context) is the opposite of the change in geostrophic wind shear driven by the Laplacian in the horizontal (sum of second derivatives in horizontal dimensions - aka 'curvature') of the temperature change driven by temperature advection (let's call this the 'thermal forcing' - TF, in this context). Both TF and MF make equal contributions to ageostrophic vertical wind shear: MF by changing the wind shear, and TF by changing the geostrophic wind shear in the opposite direction. The relative vorticity (RV) is the vertical component of the curl of the wind velocity vector, equal to the Laplacian of the streamfunction in the horizontal plane (horizontal being along an isobaric surface in x,y,p coordinates). And so the same is true for the variation of RV over height (over p in isobaric coordinates): Both MF and TF create equal ageostrophic vertical RV variation - MF by channging the vertical RV variation, and TF by changing the geostrophic vertical RV variation in the opposite direction. BUT One can add to MF the effects of advection of planetary vorticity - north/south winds in the presence of nonzero beta, and frictional/viscous torques. One can add to TF diabatic heating. Thus, the total MF is from the vertical variation (vertical derivative) of the sum of: the advection of RV, the advection of f, and the curl of viscous acceleration. And the total TF is from the Laplacian of the sum of: the temperature advection and the diabatic heating. For quasigeostrophic balance, vertical derivative of RV = -G/f * Laplacian of q where G = R/p * T/q where R is the gas constant for air, And for a given p, T/q = (p/p1000)^(R/cp) where p1000 = 1000 mb (a reference pressure level) and cp is the specific heat of air at constant pressure For the purposes of a simple scale analysis, this relationship can be written roughly in terms of a height scale H (Hp, in pressure coordinates), and length scale L, as RV/Hp ~ G/f * q/L^2 where the negative sign was dropped by assuming Hp is measured upwards (the direction of decreasing pressure). (~ can be read: "scales as" and/or "is of the same scale as") The change in vertical variation of geostrophic RV due to advection of q (proportional to the advection of T as a function of pressure: q = T*(p1000/p)^(R/cp)) is opposite the change in vertical variation of RV due to RV advection - this can be written advected RV /Hp ~ - G/f * advected q /L^2 ... Assume H = Hp for the rest of this comment: ... Well, without dragging everyone through the algebra, this implies (with conservation of IPV, where IPV/g = AV*S, S being del(q)/del(p) and AV = RV + f), where total (RV advection + f advection + curl of viscous acceleration)/H = W * RV advection/H Thus total MF = W * MF from vertical variation of RV advection and similarly, total TF = Q * TF from Laplacian of q or T advection: --- The balance equation and relationship between MF and TF can be solved for vertical motion: in terms of q advection, qad: vertical motion ~ (Q+W)*G/f * H^2/L^2 *qad } / [ G/f * H^2/L^2 * S + AV ] and in terms of RV advection, RVad: vertical motion ~ -{ (Q+W)*RVad*H } / [ G/f * H^2/L^2 * S + AV ] Vertical variation of vertical motion in pressure coordinates, in a hydrostatic approximation, requires horizontal convergence and divergence. This is the secondary adiabatic ageostrophic circulation. The Laplacian of vertical motion changes the Laplacian of q by moving q surfaces relative to p surfaces (adiabatic cooling and warming). The horizontal convergence and divergence changes AV (and thus changes RV, since, after a 'time step'**, f doesn't change because at an instant the air doesn't move and f is fixed at a given location) while conserving IPV; vertical stretching reduces S. This secondary adiabatic ageostrophic circulation (SAAC) brings the actual RV closer to geostrophic RV, both by (at least when assuming both W and Q are positive) reducing the RV changes forced by MF and reducing the q changes forced by TF. Notice that if W and Q are of the same sign, MF and TF cause SAAC of the same direction. If both changes in RV and q are reduced, it is possible for the net changes to be zero. But one effect could be said to 'win' if it is not zero. Substituting the vertical motion back into the balance equation: FOR Ross = G * H^2/L^2 * S/(AV*f) : balanced change in RV ~ RVad * [ W - (Q+W) / ( Ross + 1 ) ] balanced change in q ~ qad * [Q - (Q+W) / ( 1 + 1/Ross ) ] AND balanced change in IPV/g (where S is a basic state value) ~ RVad * S * ( W - Q / Ross ) Thus, for positive W and Q, the effect of RVad 'wins out' over qad in both balanced RVad, qad, and IPV changes, when Ross >~ Q/W whereas qad wins when Ross <~ Q/W Of course W and/or Q could be negative as well, in which cases ... - etc. It might seem odd that the change in IPV is determined by the spatial scales of MF and TF, but the IPV advection can be calculated from the TF and MF effects without SAAC, and it is the same, which is not surprising since the conservation of IPV during SAAC was used in the algebra (IPV may not be conserved during MF and TF because of viscous and diabatic contributions). And MF and TF forced IPV changes are affected by H and L because: forced change in S by TF ~ Q*qad / Hp and of course, forced change in RV by MF ~ W*RVad ~ - Hp * W * G/f * qad /L^2 NOTICE, Ross = G * Hp^2/L^2 * S/(AV*f) Thus sqrt(Ross) = Hp/L * sqrt[(G*S)/(AV*f)] If Ross = 1, L is proportional to the internal Rossby radius of deformation for a given Hp.
130271. Patrick 027 at 14:52 PM on 19 January 2009
        Volcanoes emit more CO2 than humans
        It also occurs to me that Spencer's analysis could be capturing some aspect of the annual cycle.
130272. Patrick 027 at 12:11 PM on 19 January 2009
        Volcanoes emit more CO2 than humans
        3 and 4 in last comment - What I mean - Spencer refers to striations and spirals. Are those spirals predominantly clockwise or counterclockwise? (And does it vary by the size of the spiral? Etc...) It may be that the method for figuring out climate sensitivity that Spencer is criticizing is actually not a very good method, for perhaps some of the same reasons that Spencer's own method seems lacking. But this is just one piece of the puzzle (which might have been helpful but unnecessary? - There is a lot of other evidence out there). For example, Spencer mentions use of this method on climate models. But the most clear cut way to evaluate climate model sensitivity is to have multiple runs in response to various forcings and compare. ------------ "The curve was rejected and is now accepted by the consensus" Could you show me where it is accepted?
130273. ANTILiberal at 11:54 AM on 19 January 2009
        We're heading into an ice age
        I heard about this on the radio last month, and this would prove that we are not the cause of climate change, and that industrialization is not harmful. Unfortunately, many people are still advocating global warming since they have their money on it. This seems to be the strategy for defense of these advocates: "if any part of the earth gets warmer during the industrialized age, industrialization is to blame. If the earth gets cooler, of course, industrialization is a bad thing anyway. Heads, I win. Tails, you lose!
130274. Patrick 027 at 11:45 AM on 19 January 2009
        Volcanoes emit more CO2 than humans
        The problems I saw in Spencer's approach: 1. he was looking at climate sensitivity based on Temperature and radiative fluxes (top of atmosphere (TOA)) over rather short time periods. This is not an equilibrium climate sensitivity at all. (PS if a period of 5 years is sufficient, then why isn't 40 or 100 years of warming sufficient?) 2. conceivably there could be some net global cloud feedback, as well as the ice-albedo and and water vapor feedbacks and others, to forcing of climate from CO2, etc. Over short time periods (this is part of concern 1, actually), any water vapor feedback and other feedbacks, etc., would be limited by thermal inertia of the oceans. In addition, CO2 would generally only be a feedback over longer time periods. What is the cloud feedback to cloud forcing? 'Internal Radiative Forcing' is a feedback to some other internal effect, and will react to itself... 3. If one of the graphs could be shown in enough detail, one might judge to what extent temperature fluctuations are driving radiative fluctuations and vice-versa - obviously both happen - they must, that's the physics. 4. On that note, there can be some correlation, perhaps with some lag in time or not, between cloud radiative feedback and temperature, or temperature changes, that is not entirely due to a direct forcing of temperature by clouds OR a direct forcing of clouds by temperature. The short term variability may involve fluctuations in cloud type, amount, and distribution, and in temperature and wind, etc, that are of a different nature than that of longer term changes. 5. Spencer's description of how the IPCC, etc, estimate sensitivity is not descriptive enough for me to judge what it means. ------- FROM http://www.drroyspencer.com/research-articles/satellite-and-climate-model-evidence/ "And it appears that the reason why most climate models are instead VERY sensitive is due to the illusion of a sensitive climate system that can arise when one is not careful about the physical interpretation of how clouds operate in terms of cause and effect (forcing and feedback)." This seems to set aside any work that goes into trying to realistically model clouds based on observations of clouds and weather on smaller spatial scales (relative to global) - I think 'they' do that. " The allure of models is strong: they are clean, with well-defined equations and mathematical precision. Observations of the real climate system are dirty, incomplete, and prone to measurement error. " Well, I guess we should trust the models, then, eh Spencer? :) (I just found that particular passage to be very ironic, and not just within the context of this paper.)
130275. Steve L at 07:38 AM on 19 January 2009
        Latest satellite data on Greenland mass change
        Oh dear, I missed that Mizimi was writing about Iceland and not Greenland. Mizimi, please answer Ian's questions about where you're getting your info. Looks unreliable!
130276. Quietman at 07:19 AM on 19 January 2009
        Volcanoes emit more CO2 than humans
        Sorry, I missed something that you said. The Fairbridge curve and the Solar Jerk are two different hypotheses. The curve was rejected and is now accepted by the consensus while the solar jerk still has not been accepted. They are unrelated subjects.
130277. Patrick 027 at 09:59 AM on 18 January 2009
        Arctic sea ice melt - natural or man-made?
        CORRECTION to 408: third paragraph (the one that starts: "In contrast, for the eddy thermal fluxes that would cause a decrease in the geostrophic u," ) ... "The adiabatic MMC caused by this is in the same direction as that described by the previous paragraph." The exact opposite is true. The same point was made and implied correctly in other parts of comment 408. BUT often, the two MMCs are in the same direction, with the u'v' and v'T' effects making opposite contributions to the net change in IPV and balanced wind distributions. In particular, the vertical variation in RV advection and the horizontal curvature (Laplacian) of temperature advection (following the motion of the air) tend to have opposite effects, when advection is mainly by geostrophic winds, as described previously (comments 319 - 323). Whether the RV advection or the temperature (T) advection dominates in the IPV tendency depends on length and height scales, stability, AV and f, some other things - in a relation that is very similary to the relationships in the formula for the Rossby radius of deformation. More on that later... PS the example of an SSW in Holton, p.416, (estimated from a graph) shows (in terms of zonal averages) a warming of the polar stratosphere at the 50 mb level (PS sea level pressure averages ~ 1013 mb; 1 mb = 100 Pa = 100 Newtons/square meter), most of it in about 5 days, greater than 10 K (10 deg C, 18 deg F) north of ~ 65 deg latitude, greater than 30 K at ~ 80 deg latitude; with a reduction in the zonal wind of over 10 m/s north of ~55 deg latitude, becoming easterly north of ~61 or 62 deg latitude. Holton p.415: the warmings can be as much as 40 K. An SSW involves distortion and breakdown of the westerly circumpolar vortex in the stratosphere. Enhanced planetary (Rossby) wave propagation from the troposphere, of mainly zonal wavenumbers 1 and 2 (when a wavenumber is given without units, in this context it refers to the number of wavelengths that fit around a circle of latitude; zonal wavenumbers 1 and 2 are the longest of zonal wavelengths) is "essential" (Holton p.415) to produce an SSW.
130278. Quietman at 08:47 AM on 18 January 2009
        Volcanoes emit more CO2 than humans
        ps This is spencers site. Articles and links to peer reviewed papers. http://www.drroyspencer.com/
130279. Quietman at 08:46 AM on 18 January 2009
        Christmas cartoon on melting North Pole
        Sorry, Are we in another La Nina now?
130280. Quietman at 07:11 AM on 18 January 2009
        Volcanoes emit more CO2 than humans
        Spencers argument is specifically about sensitivity to CO2. Look under Arguments, the Pacific Decadal Oscillation (at this site). I posted a link to a draft he did that they have refused to publish. I would prefer to be wrong about all this as I much prefer a warmer world but I fear that Spencer may be right. I am sure that Fairbridge was as the last two winters have been showing. The test is 2007 through 2011. Halfway there.
130281. Quietman at 07:00 AM on 18 January 2009
        Christmas cartoon on melting North Pole
        John and Phillipe In all honesty, I sincerely hope that I am wrong and that you are correct. I have lived in temps up to 140F and down to -60F and believe me I prefer heat to cold. But I simply can't believe all that science pointing to another glacation is wrong and that we are attempting to encourage it's start. La Nina is not affecting this winter and that article was posted yesterday. I have not personally experienced any warming since the Plains Blizzard of 1996. 1998 was a freak rewarming due to El Nino. The warming trend was just a weather cycle IMO, the true trend is cooling, hopefully slight.
130282. Patrick 027 at 12:17 PM on 17 January 2009
        Volcanoes emit more CO2 than humans
        In that work of Spencer we've discussed, his argument was not abotu CO2 forcing but about climate sensitivity. There is no flaw in the fundamental sense. There is uncertainty. Spencer's argument seemed ill-concieved to me - the logic isn't quite there.
130283. Patrick 027 at 12:10 PM on 17 January 2009
        Volcanoes emit more CO2 than humans
        "the average length of an interglacial BTW" Average, perhaps. Not all. Once every few interglacials, one is longer - although this is too long of a pattern to have been repeated much in the last several hundred thousand years, but there was at least one extra-long interglacial. Based on astronomical forcings, this interglacial could be one of the extra-long ones, perhaps lasting another 20,000, 30,000, or 50,000 years, even without AGW. "t won't cause a rise in sealevel because it is expanded (frozen) water that is also displacing sea water at present. " Yes, of course. Yet, the sea level is rising; Greenland is losing land-based ice (potential point of confusion: the base of the ice is below sea level in many parts, and in Antarctica too (West Antarctica in particular), but the height of the surface of the ice is such that most of the weight of the ice is not supported by the water - it will raise sea level when it melts). Antarctica may also be losing ice in total even though some parts may be gaining ice mass. "Sea level rise is within the Fairbridge curve; ie. normal or "expected"." But if it is expected, what is the expectation based on? (Fairbridge's argument about Solar jerk was based on cycles dominated by Jupiter and Saturn, but the actual forces (tides on the sun) would be dominated by Jupiter and Venus, then Earth and Mercury, before any other gas giants - and I showed earlier these would be exceedingly exceedingly small effects.) I'm really not at all convinced that the Fairbridge curve was/is based on a solid body of evidence. "I like the way you calculate out the CO2 forcing" Thank you - but actually, I only explained how it is calculated, and the physical principles on which it is based, which are as sound as the inverse square law. "but I still agree with Spencer." Spencer doesn't really make a durable point, though.
130284. Patrick 027 at 11:50 AM on 17 January 2009
        Volcanoes emit more CO2 than humans
        Regarding the P/T extinction: The concept as I understood it: There was a long ice-house period (with some significant ice, sometimes more (ice ages)) in the late Paleozoic. I've not been clear just when that ended, whether that was part of the P/T extinction or not. If it had ended but only just recently, that might have left species more vulnerable to any further warming. It was a time of continental collision - the formation of Pangea. One version: So then this Siberian trap flood volcanism starts up and persists for ~ a million years (more?), pumping CO2 into the air at a faster than typical rate. (Aerosols too, but those don't accumulate.) Eventually there is a lot more CO2. The Earth warms - maybe 5 degrees C - some extinctions occur (more on land??) The warmth causes CH4 release from the oceans. Sudden burst of warming. A total of 10 deg C more than before the flood volcanism? More extinctions. Oxygen doesn't dissolve as well in the oceans because of higher temperatures. Anaerobic bacteria that produce H2S become more commonplace. H2S in oceans, maybe some in the air. More extinctions.
130285. Philippe Chantreau at 10:40 AM on 17 January 2009
        Christmas cartoon on melting North Pole
        People have become so used to not have a winter that they're surprised when there is one.
130286. Philippe Chantreau at 10:39 AM on 17 January 2009
        Christmas cartoon on melting North Pole
        There is no such thing as weather anymore?
130287. Quietman at 09:46 AM on 17 January 2009
        A Great Science Fiction Writer Passes - Goodbye Dr. Crichton
        An interesting piece with a little insight: Scion of Frankenstein Michael Crichton, novelist and policy provocateur Ronald Bailey | February 2009 http://www.reason.com/news/show/130852.html
130288. Quietman at 09:36 AM on 17 January 2009
        Christmas cartoon on melting North Pole
        1-16-2009, MSNBC News: By Friday morning, cities and towns in 13 states reported temperatures well below zero, among them: -50 in Big Black River, Maine, in what could be a new state record -46 in Embarrass, Minn. -42 in Island Pont, Vt. -42 in Necedah, Wis. -39 in Berlin, N.H. -38 in Monticello, Iowa -36 in Sterling, Ill., possibly tying a state record -35 in Paradox, N.Y. -26 in Stambaugh, Mich. -20 in Valparaiso, Ind. -19 in Lawton, Pa. -16 in Snowshoe Mountain, W.Va. -14 in Dayton, Ohio In upstate New York, meteorologist Dave Sage said areas near Lake Erie were walloped by snow, with 2 inches falling per hour in some areas on Friday morning. As Ricky would say - Splain This Lucy
        Response: The question of specific instances of cold weather is answered here. More generally, recent cooling across 2008 was due to the cooling effect of La Nina and to a lesser extent, the solar minimum.
130289. Quietman at 07:17 AM on 17 January 2009
        Volcanoes emit more CO2 than humans
        Sea level rise is within the Fairbridge curve; ie. normal or "expected". The Arctic is the obvious problem which is why I did not mention it. But outside of Greenland it won't cause a rise in sealevel because it is expanded (frozen) water that is also displacing sea water at present. Add to that the increased sea and glacial ice in Antarctica despite the small area near S.A. and there is no reason for additional sea level rise. The planet went through a brief warm spell, a large part caused by ocean cycles but some was abnormal. The anomally clearly shows which areas and they are decidely not global. I like the way you calculate out the CO2 forcing but I still agree with Spencer. There is a fundamental flaw somewhere. Be the one to find it.
130290. Patrick 027 at 06:37 AM on 17 January 2009
        Volcanoes emit more CO2 than humans
        Here's the thing(s) about that: " Eastern Canada and the N.E. U,S, are not the only places on earth that have cooled while population centers warmed and it is from population centers that most data comes from. Why was this cooling ignored? " No, not really. The Arctic has warmed, the oceans have warmed (Aside from other data, sea level has been rising - that has to be mainly a combination of melting or temperature inceases - melting involves some of the heating occuring without temperature changes, of course). "South America, Antarctica and Africa have not experienced the same changes as Europe and PARTS of Asia. " ... " South Atlantic and Antarctic deep water is notably getting colder." The point being, you have to put all those together. It's still global warming, in the sense that there is more heat coming in then going back into space. "Glaciers in sunny california are GROWING because of the extra moisture off the Pacific." And why is that happening? "All of this climate change can easily be explained without super powerful CO2 forcing that historically does not seem to very powerful at all." It could be explained without CO2, but with strain and guessing. Much or most can be explained very very very very very very very very easily with a net forcing that is the sum of contributions from the changes in CO2, somewhat smaller from the rest of GHGs, a sizable likely negative aerosol contribution, rather small contributions from episodic volcanoes and solar radiation, and also, some other effects of ozone depletion (that doesn't explain the general global warming, etc, but it has effects). Etc.
130291. Philippe Chantreau at 16:07 PM on 16 January 2009
        Arctic sea ice melt - natural or man-made?
        You need to stop insinuating that the cites are some ploy to try to convince people of something or some way to establish a "consensus." It is a tool that researchers can use to access more information. Accessorily, it helps to determine the relevance and usefulness of a paper. The example I gave in post #394 is about diabetes and genetic, no suspicious consensus problem in this now, is there? You've spent too much time reading conspiracy BS on so-called skeptic sites,IMO.
130292. Quietman at 09:09 AM on 16 January 2009
        Arctic sea ice melt - natural or man-made?
        Phillippe Actually I do spend a lot of time at both PLos Biology and PLos ONE. Granted I am only lookong at Paleontology and Evolution related papers. I check the references but I have never noticed a "number cited" but you may be right, I may have overlooked it as I don't consider consensus important. I look to see WHO is referenced as there are authors I trust and others I do not.
130293. Quietman at 08:49 AM on 16 January 2009
        Volcanoes emit more CO2 than humans
        Also you might want to read Peter Ward's work on the PT extinction (not the media coverage that assume CO2). While Ward does not recognize the importance of the Antarctic impact, he does cite the Siberian Traps that it created as releasing METHANE and poisionous gas. While the gas may have caused a GH condition, the GHG did not cause the extinction event, which (as he points out in Gorgon and elsewhere) was a two stage extinction. First the oceans died (90% of all ocean species) and was followed by land species (70%). What most forget when reading about the PT extinction is that the Pennsylvanian-Permian Ice Age had just closed and the planet had warmed (naturally) prior to the extinction event, just like right now after 12000 years of interglacial (the average length of an interglacial BTW).
130294. Quietman at 08:38 AM on 16 January 2009
        Volcanoes emit more CO2 than humans
        ps Glaciers in sunny california are GROWING because of the extra moisture off the Pacific. I have posted links to all of these articles that describe what I have said. All of this climate change can easily be explained without super powerful CO2 forcing that historically does not seem to very powerful at all.
130295. Quietman at 08:35 AM on 16 January 2009
        Volcanoes emit more CO2 than humans
        Patrick You may recall that when we started talking about Bertha we took note that tropical storms had been forming farther east, meaning a change in air currents. Eastern Canada and the N.E. U,S, are not the only places on earth that have cooled while population centers warmed and it is from population centers that most data comes from. Why was this cooling ignored? South America, Antarctica and Africa have not experienced the same changes as Europe and PARTS of Asia. In fact, it has been noted that most warming has been on the western coasts of the Americas and Europe. If you check the ocean threads here you will see that overall the oceans have not warmed but there ate definate warm currents and hot spots. South Atlantic and Antarctic deep water is notably getting colder. Referring to this as "climate change" is quite accurate, but it is by no means "global warming".
130296. Philippe Chantreau at 18:44 PM on 15 January 2009
        Christmas cartoon on melting North Pole
        Sure, he's OK if you carefully pick what years to compare with. NSIDC put things in perspective: http://nsidc.org/arcticseaicenews/ Of course, we're not considering volume here...
130297. Tanuki at 12:45 PM on 15 January 2009
        Water vapor is the most powerful greenhouse gas
        Help please! I have not be able to find the paper disclosing the physics of the carbon dioxide and water interactions. Here I see only references to climate models and empirical studies, I would prefer to see the description of the actual phyical chemistry.
130298. Mizimi at 01:32 AM on 15 January 2009
        Water vapor is the most powerful greenhouse gas
        Chris; the paper is Santer 2007 noted above. And you didn't answer the question....how do climate models incorporate the heat emitted from life which is independant of IR ? Also, as you have previously averred, the WV content of the atmosphere is dependent on P~T, (subject to availability)so when it is removed during photsynthesis it is readily replaced..returning to "equilibrium"; so WV emitted by air breathers adds to the atmospheric content.
130299. Patrick 027 at 15:44 PM on 14 January 2009
        Arctic sea ice melt - natural or man-made?
        EP Flux AND SSWs - TOGETHER AGAIN (FIXED EARLIER PROBLEM - corrections to comments 403-405): If the zonal wind is slowing down in geostrophic balance, this implies decreasing stability (warming below, cooling above) on the poleward side and the opposite on the equatorward side. Deceleration by u'v' flux, taken in isolation, first causes an ageostrophic decrease in u (the zonal wind), which is then acted on by the coriolis effect, causing poleward displacement, which is balanced by adiabatic sinking below and rising above on the poleward side (vertical stretching) and the opposite on the equatorward side, which causes an adiabatic temperature change pattern as described in the last paragraph; it reduces the initial change in u but balances the remainder with a change in the mass distribution. The meridional circulation is the momentum-flux forced adiabatic MMC; the coriolis acceleration of the poleward part of the MMC increases u; thus reducing the initial change in u. A similar MMC (the VMC) would occur in response to a reduction of u forced directly by friction. In contrast, for the eddy thermal fluxes that would cause a decrease in the geostrophic u, taken in isolation, they first cause an increase in the ageostrophic u (by directing the temperature changes in the same direction as described two paragraphs previously). The adiabatic MMC caused by this is in the same direction as that described by the previous paragraph. It reduces the temperature changes but the coriolis acceleration of the equatorward part of the MMC causes a decrease in u to balance the remainder of the temperature changes. ----------- The two MMCs are in the opposite direction. For the mechanism of SSWs, the adiabatic MMC forced by the u'v' flux divergence must be dominant, or else the DMC caused by the temperature changes must be able to act fast enough to have a 'sudden' effect. (The changes in temperature tend to shift radiative fluxes so as to diabatically cool the adiabatically-warmed areas, etc, and the adiabatic circulation which occurs in response to the diabatic processes would cause poleward drift at the level of the EP flux convergence. However, I'd guess this process isn't fast enough for something 'sudden' (how sudden is sudden? - will report back).) THIS is because, while if both u'v' and v'T' make contributions to EP flux convergence, the resulting temperature changes are correct for an SSW, an SSW also involves poleward drift at and around the level of the EP flux convergence. ----------- Seperating the DMC from it's adiabatic MMC response: The diabatic process doesn't by itself cause any vertical motion in x,y,p coordinates. It just moves the isentropes. In x,y,q coordinates, this looks like vertical motion relative to fixed isentropes. The adiabatic MMC response to the diabatic changes reacts by moving the isentropes part-way back (but not all the way back) to their earlier positions, but in so doing requires vertical motion in x,y,p in the same direction as that which occured in the DMC in x,y,q. Vertical stretching and compression in x,y,p change the stability part way, but not all the way, back to the pre-DMC values, while the corresponing horizontal convergence and divergence, while conserving the DMC-generated IPV changes, cause changes in AV and thus RV (tending to be in the same direction as the diabatic IPV change) so as to balance the remaining portion of the pressure, temperature, and stability changes. ----------- A question that may come up - as the EP flux convergence propagates downward in response to changing wave-propagation properties (more later on why that happens), shouldn't the temperature changes that occured below the EP flux convergence reverse themselves as the level of EP flux convergence shifts downward? I don't know - apparently it doesn't, at least not fully. Perhaps it has something to do with changes in pressure and stability with height? -------------- What is the EP flux and what isn't it? I think the adiabatic MMC response to diabatic processes must be included in the DMC, or else it wouldn't make sense to show a DMC (residual MMC) circulation on the graph in Holton (in log-p coordinates - not isentropic coordinates) However, a long term average for a stable climate must assume there is no net movement of isentropes, so the vertical motion of diabatic processes must automatically appear in log-p coordinates, although this includes the adiabatic response AND something else... Holton doesn't explicitly note a VMC but that may just be because it's small. Or maybe it is included by approximation with the DMC just because the DMC was calculated by assuming VMC = 0 (an approximation). All adiabatic MMCs (inluding those in response to diabatic and viscous processes) also produce momentum, temperature, and IPV fluxes directly by advection, but they are, as I understand it, small in comparison to those fluxes in the EP flux and the sources and sinks directly from diabatic and viscous processes. Since additional MMCs would have to react to such processes, it is useful approximation to set them aside (at least for the purposes in Holton Ch. 10). Ealier I described how it would be possible to have (at least over a shorter time period ??) adiabatic zonal average vertical motion without vertical displacement of average q. However, in that case, there would be zero average adiabatic cooling or warming. Just something to keep in mind.
130300. David Horton at 12:32 PM on 14 January 2009
        Climate's changed before
        This The_skeptic_who_came_in_from_the_cold.html is an attempt to answer, for a skeptic (not denialist) friend, his proposition that since climate had changed before there was nothing to either explain or worry about. It is an attempt to distinguish between genuine skepticism and malign, planet-hating, denialism. The comment from tommybar "even if C02 is contributing, which it may have/be, a lot has been shown that it's 'greenhouse' ability is a logarithmic function, and that it has already contributed as much as it can" is interesting because it has suddenly started cropping up, in blogs around the world almost simultaneously. Could it be the latest talking point provided for the denialist anti-environment lobby? Funny how they all sing to the same tune (ice caps on Mars, Antarctic ice growing, planet now cooling) at the same time with each new attempt to stack the card deck, shuffle the pea, while distracting the punters.

Prev  2598  2599  2600  2601  2602  2603  2604  2605  2606  2607  2608  2609  2610  2611  2612  2613  Next