Georg Heygster,
Christian Melsheimer, IUP Uni Bremen
Annette Rinke, Klaus Dethloff,
Alfred-Wegener-Institut, Potsdam
A. Ice sheets
Currently, precipitation is one of the largest
uncertainties in the mass budget of the large ice sheets in Antarctica and Greenland. CryoSat
will determine the change of ice height, driven by precipitation, melting and
ice displacement. This contribution aims to determine the precipitation from a
regional atmospheric model which in turn will be adjusted by including daily
maps of total atmospheric water vapor, determined
using a recent remote sensing technique to retrieve values in the range from 0
to 6 kg/m2 over Antarctic sea ice and land ice from data of the humidity
sounders SSM/T2 aboard the DMSP satellite series. Transferring this procedure
to the NOAA AMSU-B satellite sensors, including Arctic conditions and producing
daily gridded fields for the years 1998 to 2004 will
allow to improve a regional atmospheric model.
The results of long-term runs will be used to
describe quantitatively the annual and decadal variability of the atmospheric
water vapor, and the snow accumulation on the
Antarctic and Greenland ice sheets as an important part of
the hydrological balance and the mass balance of the large ice sheets. At the
same time, this project has strong relations to land ice modeling
activities and to GLIMS (Global Land Ice Measurements from Space).
B. Sea Ice
A similar estimate of precipitation will be
carried out over sea ice. As the regime is more humid in these regions, in
addition to the total water vapor, the cloud liquid
water path will be estimated from satellite measurements of the passive
microwave sensors SSM/I and AMSR. These fields will also be used to adjust the
atmospheric models, e.g., by nudging techniques.