Moisture source of precipitation in Western Dronning Maud Land, Antarctica

Moisture sources for snow falling in Dronning Maud Land (I)ML), Antarctica, are calculated for 1998 using three dimensional 5-days backward air parcel trajectories. The drilling site of the European Project on Ice Coring in A ntarctica (EPICA) in DML is chosen as the main arrival point (75.0 degreesS , 0.01 degreesE). A distinction is made between trajectories with and Witho ut snowfall at arrival. Of the snowfall trajectories, 40-80% are located in the Atlantic Ocean Within four days before arrival. Evaporation along thes e trajectories is largest three to four days before arrival. The air parcel s are then located between 40 degrees and 60 degreesS in the Atlantic Ocean where surface temperatures range between 0 degrees and 20 degreesC. A case study for May 1998 shows that when snow falls exceptionally high temperatu res and wind speeds prevail in the atmospheric boundary layer. The position of the trajectories in the boundary layer suggests a source region for thi s event between 40 degrees and 50 degreesS and 20 degrees and 60 degreesW i n the Atlantic Ocean, where sea surface temperatures vary between 5 degrees and 15 degreesC.