基于比湿订正拉格朗日模型的新疆短时强降水的水汽来源

Water Vapor Sources of Short-Time Heavy Rainfall in Xinjiang Based on Specific Humidity-Adjusted Lagrangian Modelel

基于中国地面气象站逐小时观测资料、GDAS气象数据及2016—2017年NCEP/NCAR再分析资料,利用拉格朗日后向轨迹模型,结合比湿变化对新疆短时强降水的水汽来源进行订正。结果表明:(1)新疆的水汽主要来源于包括里海、黑海、地中海、大西洋、北冰洋和附近的内陆地区;新疆常年受西风影响,偏南西风影响较大;(2)阿尔泰-塔城森林草原自然区和准噶尔盆地荒漠自然区水汽路径总体偏北,伊犁-巴音布鲁克(中天山)自然区和哈密-吐鲁番荒漠自然区受陆地水汽源的影响更大,而塔里木盆地极端干旱荒漠自然区水汽路径总体偏南。聚类分析结果显示,阿尔泰-塔城森林草原自然区的水汽来自于欧洲,准噶尔盆地荒漠自然区的水汽主要来自于中亚、里海和蒙古高原,塔里木盆地极端干旱荒漠自然区水汽主要来自塔里木盆地、西亚、中亚和黑海;(3)经过比湿判断水汽补给情况后,气团回溯路径普遍变短,水汽主要来自中亚、黑海、里海和附近的陆地;从主要水汽源地的传输水汽平均需要3. 5 d左右,季节上表现为夏季的水汽源地最近,秋季的水汽源地较远,区域上阿尔泰-塔城森林草原自然区水汽源地最远,哈密-吐鲁番荒漠自然区水汽源地最近;(4)新疆各起始高度上的降水主要受偏北和偏南的西向气流影响,且从对水汽的贡献来看,偏北的西向气流大于偏南的。

The Lagrangian Backward Trajectory Model was used to research the moisture sources of short-time heavy rainfall in Xinjiang based on the change of specific humidity and the hourly observed data from China Ground Weather Station,GDAS meteorological data and NCEP/NCAR data during the period of 2016-2017.The results showed that:(1)Water vapor sources of Xinjiang were mainly the Caspian Sea,Black Sea,Mediterranean Sea,Atlantic Ocean,Arctic Ocean and nearby inland areas.Xinjiang was affected by the westerly wind all the year round,especially the westerly wind in the south;(2)The water vapor transport paths in the Altay-Tacheng Forest Grassland Natural Area and the Desert Natural Area in the Junggar Basin were holistically northerly,and the Ili-Bayanbulak(the central Tianshan Mountains)Natural Area and Hami-Turpan Desert Natural Area were strongly affected by the land water vapor sources,and the water vapor transport path in the Extreme Arid Desert Natural Area in the Tarim Basin was holistically southerly.The result of cluster analysis revealed that the water vapor in the Altay-Tacheng Forest Grassland Natural Area came from Europe;it in the Desert Natural Area in the Junggar Basin came mainly from Central Asia,the Caspian Sea and Mongolian Plateau;and it in the Extreme Arid Desert Natural Area in the Tarim Basin came mainly from the Tarim Basin,West Asia,Central Asia and the Black Sea;(3)After judging the water vapor replenishment by specific humidity,the backtracking path became short,and the water vapor came mainly from Central Asia,the Black Sea,Caspian Sea and nearby land.The water vapor transmission from the main sources needed 3.5 days in average.Seasonally,the water vapor sources were the closest in summer and far in autumn.Regionally,the sources were the farthest in the Altay-Tacheng Forest Grassland Natural Area and the closest in the Hami-Turpan Desert Natural Area;(4)Precipitation in Xinjiang was mainly affected by the northerly and southerly westward airflows,and the northward westward airflow contributed more than the southerly westward one.