北疆冬季降水异常的环流特征和水汽输送分析

Analysis of circulation feature and water vapor transport of winter precipitation anomaly in Northern Xinjiang

利用1979—2016年北疆冬季49个气象站日降水资料和ERA-Interim再分析资料(0.5°×0.5°),对北疆冬季降水的时空特征、水汽输送及环流形势进行研究。结果发现,北疆冬季降水的水汽输送通道有2条:地中海-黑海-里海-咸海-巴尔喀什湖-北疆为西方路径,红海-波斯湾/里海南侧-巴尔喀什湖-北疆为西南路径,其中以西方路径为主。500 h Pa高纬高(低)压、西伯利亚瞬变低压(高压)和伊朗高原脊(槽)的异常活跃促使北疆一致降水偏多(少),500 h Pa斯堪的纳维亚半岛正(负)距平、西伯利亚-伊朗高原负(正)距平的活跃和地中海低压槽(高压脊)的异常活跃导致北疆西北部降水偏多(少),500 h Pa巴尔喀什湖西南侧西南-东北负(正)距平的活跃和西伯利亚正(负)距平的活跃造成北疆西部降水偏多(少),其中全区降水一致型是北疆降水的主要分布型。

Circulation feature and water vapor transport of winter precipitation anomaly were studied by using the ERA-Interim reanalysis data and the daily rainfall observations of 49 meteorological stations in winter in Northern Xinjiang during 1979-2016.The analyzed results showed that two routes of water vapor transport had an effect on winter precipitation in Northern Xinjiang.The west water vapor passage was Mediterranean Sea-Black Sea-Caspian Sea-Aral Sea-Balkhash Lake-Northern Xinjiang,the southwest water vapor passage was Red Sea-Persian Gulf/southern Caspian Sea-Balkhash Lake-Northern Xinjiang.Two of the passages,the west water vapor passage was more important.The reasons for more(less)winter rainfall in Northern Xinjiang were that,on 500 hPa,high(Low)pressure was anomaly active in high latitude,transient low-pressure disturbance(high pressure)was unusually active in Siberia and high-pressure ridge(low-pressure trough)was unusually in Iranian plateau.The reasons for more(less)winter rainfalls in the northwest of Northern Xinjiang were that,on 500 hPa,positive(negative)anomaly was active in Scandinavian Peninsula,negative(positive)anomaly was active in Siberia-Iranian plateau,and low-pressure trough(high-pressure ridge)was unusually active in Mediterranean.The reasons for more(less)winter rainfalls in the west of Northern Xinjiang were that,on 500 hPa,negative(positive)anomaly was active in the southwest side of the Balkhash Lake,positive(negative)anomaly was active in Siberia.Three of the distributions,the most main distribution pattern was consistent in wintertime precipitation in Northern Xinjiang.