2001b: Modeled precipitation variability over the Greenland Ice Sheet

• Main Authors: David H. Bromwich, Qui-shi Chen, Le-sheng Bai, Elizabeth N. Cassano, Yufang Li
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Greenland; ice core; Ice Sheet
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.669.4907; http://polarmet.osu.edu/PMG_publications/bromwich_chen_jgr_2001.pdf

Abstract. On the basis of the evaluation of recent Greenland precipitation studies, some of the deficiencies in the modeled precipitation are probably related to the topographic data employed in modeling. In this paper the modern digital elevation data of Ekholm [1996] is used. If the horizontal pressure gradient force in o coordinates is separated into its irrotational and rotational parts, which are expressed by the equivalent geopotential and geo-stream-function, respectively, the topographic effect on the precipitation can be accurately modeled. The equivalent geopotential and geo-stream-function are implemented in a fully consistent manner in the generalized equation in this paper. A simplified large-scale condensation without evaporation of condensate is also used. These improvements are combined to yield an improved dynamic method. Two aspects of the precipitation distribution are refined by the improved dynamic method. One is the 10 cm yr-t contour near Summit, Greenland, and the other is a relative large precipitation area centered near the point (70øN, 49øW). Extensive comparisons are made between the retrieved precipitation and the observed annual accumulation time series from 11 ice core sites on the ice sheet. The modeled precipitation from the original method must use scalers to have a high degree of interannual cr•rmspondence between the measured accumulation and the retrieved precipitation, but the