Funny thing about that antarctic warming it only shows up in the satellite data the ground based weather ovservation station show a cooling trend has been under way since the mid 80's.
It is very difficult to obtain a correct ice cover using satelittes, due to cloud cover....
Not affected by weather;
Title:
Antarctic Ice Sheet Mass Variation Using GRACE Satellite Gravity Data- Removal of Atmospheric Correction Error and Recalculation of the Interannual Mass Trend-
Authors:
Yamamoto, K.; Fukuda, Y.; Doi, K.
Affiliation:
AA(Research Institute for Humanity and Nature, 457-4 Motoyama, Kamigamo, Kita-ku, Kyoto, 603-8047, Japan ;
yamamoto@chikyu.ac.jp), AB(Department of Geophysics, Graduate School of Science, Kyoto University, Kitashirakawa Oiwake-cho, Sakyo-ku, Kyoto, 606-8502, Japan ;
fukuda@kugi.kyoto-u.ac.jp), AC(National Institute of Polar Research, 1-9-10, Kaga, Itabashi-ku, Tokyo, 173-8515, Japan ;
doi@nipr.ac.jp)
Publication:
American Geophysical Union, Fall Meeting 2008, abstract #G31A-0643
Publication Date:
12/2008
Origin:
AGU
AGU Keywords:
0726 Ice sheets, 1218 Mass balance (0762, 1223, 1631, 1836, 1843, 3010, 3322, 4532), 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
Abstract Copyright:
(c) 2008: American Geophysical Union
Bibliographic Code:
2008AGUFM.G31A0643Y
Abstract
An accurate knowledge of Antarctic ice sheet mass trend is one of the important issues for the study of global scale sea level change. GRACE has provided information on the temporal mass variations on the Earth in the form of monthly gravity field solutions, and has enabled us to monitor the ice sheet mass changes directly. However, GRACE cannot distinguish between the various sources of the mass variations. It is well known that Post Glacial Rebound (PGR) also causes large mass trends in Antarctica. To estimate Antarctic ice sheet mass change, PGR mass trend should be estimated and subtracted from the GRACE"fs mass trend. One of the methods to estimate PGR mass trend is to compare elevation change data from ICESat satellite altimetry with mass variation data from GRACE satellite gravimetry. Using GRACE and ICESat data, we previously estimated PGR mass trend in Antarctica and obtained agreeable value for some large mass trend areas. However, because of large errors and limited time span of both GRACE and ICESat data sets, it is difficult to obtain reliable value for small mass trend areas. One of the errors which give serious effect on the small mass trend area in Antarctica is modeling error of short time period atmospheric variation. In the GRACE monthly data processing, ECMWF operational objective analysis data is routinely used to remove atmospheric pressure effect for the purpose of the de- aliasing of the monthly solutions. However, the atmospheric model error is relatively large in Antarctica compared to other areas mainly because of small number of the reliable ground and satellite data. In this study, to improve the ice sheet mass estimation of small mass trend area in Antarctica and to obtain more reliable continental scale Antarctic ice sheet mass variation, we estimated and corrected the atmospheric modeling error in the GRACE monthly solutions. We firstly investigated correlation between GRACE monthly gravity field solutions in Antarctica and monthly average of atmospheric pressure, and removed the error of the atmospheric monthly components from the GRACE monthly solutions. We assumed that the obtained GRACE"fs residual data can be mainly explained by the 3 following components: i.e. ice sheet mass variation, PGR mass trend and aliasing error from insufficient removal of short period atmospheric components. Spatial and Temporal correlation between the residual GRACE data and these 3 components are investigated and estimated atmospheric aliasing error by the least squares method. We used ICESat ice sheet elevation data obtained for the calculation. Using the corrected monthly solutions, we calculated Antarctic ice sheet mass trend and PGR mass trend, and assessed how much the uncertainty of the Antarctic ice sheet mass trend is improved by the correction.
Antarctic Ice Sheet Mass Variation Using GRACE Satellite Gravity Data- Removal o