Sunday, August 24, 2014
Large conclusions drawn from just 3 years of Cryosat-2 data
Even using ICEsat data extends the series to only 5 years -- far too little to support claims of a trend. A larger series could reveal very different earlier changes. The report below is objective enough. It is only the spin Warmists are putting on it that is fanciful. Note that the report below admits that the Antarctic sheet is both thickening and thinning (in different places) -- so any trend is not even Antarctic-wide, let alone global
Elevation and elevation change of Greenland and Antarctica derived from CryoSat-2
By V. Helm, A. Humbert, and H. Miller
This study focuses on the present-day surface elevation of the Greenland and Antarctic ice sheets. Based on 3 years of CryoSat-2 data acquisition we derived new elevation models (DEMs) as well as elevation change maps and volume change estimates for both ice sheets. Here we present the new DEMs and their corresponding error maps. The accuracy of the derived DEMs for Greenland and Antarctica is similar to those of previous DEMs obtained by satellite-based laser and radar altimeters. Comparisons with ICESat data show that 80% of the CryoSat-2 DEMs have an uncertainty of less than 3 m ± 15 m. The surface elevation change rates between January 2011 and January 2014 are presented for both ice sheets. We compared our results to elevation change rates obtained from ICESat data covering the time period from 2003 to 2009. The comparison reveals that in West Antarctica the volume loss has increased by a factor of 3. It also shows an anomalous thickening in Dronning Maud Land, East Antarctica which represents a known large-scale accumulation event. This anomaly partly compensates for the observed increased volume loss of the Antarctic Peninsula and West Antarctica. For Greenland we find a volume loss increased by a factor of 2.5 compared to the ICESat period with large negative elevation changes concentrated at the west and southeast coasts. The combined volume change of Greenland and Antarctica for the observation period is estimated to be −503 ± 107 km3 yr−1. Greenland contributes nearly 75% to the total volume change with −375 ± 24 km3 yr−1.
The Cryosphere, 8, 1539-1559, 2014.
Posted by John J. Ray (M.A.; Ph.D.).