Comments 1 to 6:

1. Brian Purdue at 13:12 PM on 31 December, 2012
   Well, that’s very interesting - best/most popular “science websites”. I looked them up and WUWT, Jo Nova etc. are nowhere to be seen. Now best “science blog sites” is a different matter. There are WUWT and the rest of the pseudoscience crowd. Must be the dodgy voting system that the blogosphere folks use to come to such a startling conclusion. Skeptical Science has won an award for demolishing denier’s myths, and if they changed the blogosphere voting system would undoubtedly beat the denier blog sites hands down. Go Skeptical Science, and fully informed New Year to all us readers.
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2. From Peru at 14:19 PM on 31 December, 2012
   I have made a comment on the previous open thread, about one article at WUWT: The Geodetic Reference Antenna in Space (GRASP) It claims that the current Terrestrial Reference Frame is riddled with sistematic errors, making satellite Sea surface altimetry (TOPEX-POSEIDON-JASON1-JASON2) and gravimetric (GRACE) measurements to be unreliable data. If this issue is not clarified, it could become a major argument against global warming, perhaps one of the strongest ones.
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3. Brian Purdue at 14:52 PM on 31 December, 2012
   From Peru@2 Hasn’t Watts got two eyes in his head?
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4. KR at 15:11 PM on 31 December, 2012
   From Peru - First of all, the GRACE satellites have a gravimetric resolution on the Earths surface of roughly 100km, and their intersatellite distances are measured on very short time frames (many times per orbit), meaning that any long-term drift in reference frame will have essentially no effect. For gravimetric measurements this is a red herring fallacy, as the issue simply won't affect the measures. Secondly, WRT sea surface altimetry, long-term drifts in reference frame might be more of a problem. In which case we can cross-check against tide gauge data, as per Church and White 2011:

   The linear trend from 1900 to 2009 is 1.7 ± 0.2 mm year−1 and from 1961 to 2009 is 1.9 ± 0.4 mm year-1. However, there are significant departures from a linear trend. We estimate an acceleration in GMSL by fitting a quadratic to the time series, taking account of the time variable uncertainty estimates. From 1880 to 2009, the acceleration (twice the quadratic coefficient) is 0.009 ± 0.003 mm year−2 (one standard deviation). This estimate is slightly less than but not significantly different from the (one standard deviation) estimate of Church and White (2006) of 0.013 ± 0.003 mm year−2, but still significantly different from zero at the 95% level. From 1900 to 2009, the acceleration is also 0.009 ± 0.004 mm year-2...

   Emphasis added - yes, there is an acceleration of sea level rise, shown by data wholly independent of satellite altimeters. "If this issue is not clarified, it could become a major argument against global warming, perhaps one of the strongest ones." Well, no! There are many independent lines of evidence, all pointing to global warming - as with sea level, with both satellite and tide gauge data sets. The 'skeptics' continue looking for a single issue, a silver bullet, to prove their case - and they continue to be shown to be (mixing metaphors a bit here) making mountains out of trivial molehills.
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5. From Peru at 16:41 PM on 31 December, 2012
   Thank you KR for the response. You could be 100% sure that I disagree with the Watts et al. crowd arguments and methods (I was some time ago even insulted when commenting at WUWT). I was just worried by the implications of that reference frame issue,because an accurate and precise measurement of sea level rise is key for tracking the both the accumulation of heat in the ocean and ice sheet melting. I guess it would take a whole post to deconstruct this WUWT story...
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6. Tom Curtis at 17:07 PM on 31 December, 2012
   From Peru, the report is about a NASA mission which will probably significantly improve the accuracy of altimeter and mass concentration measurements. However, reducing the error bars of measurement (what the Satellite will do) is not the same as reducing the measured trend. It may even result in an increase in the measured trend. Deniers always assume the later is impossible, ie, that any measurement error always works in favour of acceptance of global warming - despite frequent examples to the contrary. We, however, don't know whether trends will increase, decrease or stay the same with more accurate measurement until the data is generated. In the meantime, I will note two points: 1) Even if the GRASP teams simulated corrections turn out to be an accurate prognosis, the sea level rise will still show an acceleration; and 2) It is unlikely that the sea level data will shift appreciably because, as noted by KR above, ground based data shows the same rate of sea level rise.
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