Precipitation over Greenland and its relation to the North Atlantic Oscillation
Precipitation over Greenland and its relation to the North Atlantic Oscillation
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格陵兰岛降水及其与北大西洋涛动的关系
DOI：
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发表时间：
1999
期刊：
影响因子：
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通讯作者：
R. Cullather
中科院分区：
文献类型：
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作者：
D. Bromwich;Qiu;Yufang Li;R. Cullather
本文用σ坐标下的等效等压面高度的ω方程方法反演格陵兰岛的降水。这种方法的目的是准确地代表格陵兰冰盖对大气运动和降水的地形影响。从1985年到1996年，整个格陵兰岛的11年平均降水量为376 mm yr-1，这接近于冰川学数据估计的346 mm yr-1的长期平均降水量。整个格陵兰岛的降水量显示，1986年的最大值为472 mm yr-1，1995年的最小值为309 mm yr-1。北大西洋大气环流的主要年际变化可以用北大西洋涛动指数的变化来表示，这在冬季最为明显。结果表明，当NAO指数增大时，格陵兰的总降水量减少，反之亦然。1985-1995年这两个系列之间的相关系数为-0.75。格陵兰岛南部的平均降水量是福尔斯的主要降水区，冬季的平均降水量与NAO指数的关系更为密切，相关系数为-0.80。这种关系可以从高指数月和低指数月的海平面气压和格陵兰降水的合成图中理解。在NAO指数高值的几个月里，冰岛低点很强。在NAO指数值较低的月份，月平均低压位于格陵兰西南部拉布拉多海上空。格陵兰东南海岸的降水量在低NAO指数的月份比高NAO指数的月份大约大100毫米。在NAO指数低的月份，整个格陵兰岛的降水量较高。从1985年至1995年，整个格陵兰及其南部和中西部沿海地区的年降水量呈明显下降趋势，每年约下降3%。
The ω equation method based on an equivalent isobaric geopotential height in σ coordinates has been used to retrieve the precipitation over Greenland. This approach is designed to accurately represent the topographic effects of the Greenland Ice Sheet on atmospheric motion and precipitation. The 11 year mean precipitation from 1985 to 1996 over all of Greenland is 376 mm yr−1, which is close to the long-term mean precipitation of 346 mm yr−1 estimated from glaciological data. The precipitation over all of Greenland shows that the largest value in 1986 is 472 mm yr−1 and the smallest value in 1995 is 309 mm yr−1. The major interannual variability of the atmospheric circulation in the North Atlantic can be represented by the variation of the North Atlantic Oscillation (NAO) index, which is most pronounced during winter. It is found that if the NAO index increases, the total precipitation over Greenland decreases, and vice versa. The correlation coefficient between these two series for 1985–1995 is −0.75. The mean precipitation over southern Greenland, where the majority of precipitation falls, is more closely related to the NAO index in winter, and their correlation coefficient is −0.80. This relationship can be understood from the composite maps of sea level pressure and Greenland precipitation for the high and low index months. During months of high NAO index values, the Icelandic Low is strong. During months of low NAO index values, the monthly mean low is located to the southwest of Greenland over the Labrador Sea. Precipitation amounts over the southeast coast of Greenland are about 100 mm larger during the low NAO index months than the high NAO index months. Precipitation over all of Greenland during the low NAO index months is higher. There are significant downward trends in annual precipitation from 1985–1995 for all of Greenland and its southern and central west coastal regions, amounting to about 3% per year.