[en] The daily melt extent on the Greenland ice sheet can easily be retrieved from satellite
observations and therefore is a very useful index to study the surface mass balance
(SMB) evolution of the last years. It is also particularly helpful for the validation of
a model because there is little in-situ observations on the Greenland ice sheet. The
remote sensing melt-detection algorithms use the changes in microwave brightness
temperatures during snowmelt. The most used one on Greenland is the cross-polarized
gradient ratio (XPGR) method from Abdalati and Steffen (1997)*. It was found from
a comparison with simulations made by the regional climate model MAR (Modèle
Atmosphérique Régional) that the rainfall on the ice sheet in summer perturbs the
melt signal detected by XPGR via the 37-Ghz vertical channel. An improved XPGR
algorithm was developed. We present here our motivation to modify the XPGR.
An intercomparaison between the SSM/I derived observations and the MAR is
performed. The aim is to validate our model, in order to study the SMB for future
climate. The simulated extent and time evolution of the wet snow zone compares
better with satellite derived data when the modified XPGR method is used.
Disciplines :
Earth sciences & physical geography
Author, co-author :
Fettweis, Xavier ; Université de Liège - ULiège > Département de géographie > Topoclimatologie
Language :
English
Title :
Greenland ice sheet melt: intercomparison between SSM/I and a regional climate model