气候异常年份青海湖沙柳河流域降水水汽来源对比研究

Comparative Study on the Sources of Precipitation Water Vapor in the Shaliu River Basin of Qinghai Lake in Abnormal Climate Years

气候变化深刻影响水分收支与水汽循环,研究气候异常条件下水汽来源对研究区域水循环具有重要意义.2017年和2019年分别为拉尼娜和厄尔尼诺年,选取这两年典型月份的GDAS(全球资料系统)数据,利用HYSPLIT(Hybrid Single Particle Lagrangian Intergrated Trajectory)拉格朗日模式对气候异常年份下青海湖沙柳河流域的降水水汽来源进行了对比研究,以期为该流域水循环研究提供理论依据.结果表明:(1)2017年和2019年青海湖沙柳河流域降水水汽来源4月前均以西向进行水汽输送,4月后东向水汽开始逐渐输送,直到9月,东向水汽输送逐渐减弱,西向水汽输送逐渐增强.(2)沙柳河流域2017年水汽来源与2019年水汽来源相比,沙柳河流域2019年北向水汽来源比2017年较早,西向水汽输送向东向水汽输送转变较早;2017年沙柳河流域受西向水汽输送时间较长,输送路径单一.(3)2017年拉尼娜发生期加剧了沙柳河流域水汽西向输送强度,缩短了东向水汽输送时间;2019年厄尔尼诺发生期减弱了该流域水汽西向输送强度,增加了北向水汽输送路径,延长了东向水汽输送时间.

Climate change profoundly affects the water budget and the water vapor cycle,and studying the source of water vapor under abnormal climate conditions is of great significance to the study of the regional water cycle. It is well known that the year 2017 and 2019 are La Niña and El Niño years,respectively. Therefore,GDAS(Global Data System)meteorological data of January,April,July and September in 2017 and 2019 are used to better study the sources of precipitation and water vapor in climate abnormal years,the data comes from the National Environmental Forecast Center of the National Oceanic and Atmospheric Administration(NOAA).Existing studies have shown that the HYSPLIT Lagrangian model is widely used not only in the study of atmospheric pollution sources but also in the study of meteorological and precipitation water vapor sources. Therefore,this study uses the HYSPLIT Lagrangian model to compare the sources of precipitation and water vapor in the Shaliu river basin of Qinghai Lake in the year of abnormal climate. The comparative study is expected to provide theoretical reference for the study of the water cycle in the basin. The results showed that:(1)the water vapor source of precipitation in the Shaliu river basin of Qinghai Lake in 2017 and 2019 was mainly westward water vapor transport before April. After April,the source of water vapor began to gradually carry eastward transportation. Until September,the water vapor transportation in the basin gradually weakened from the east direction,and the water vapor transportation gradually increased in the west direction.(2)Compared with the sources of water vapor in the Shaliu river basin of Qinghai Lake in 2017 and 2019,the source of water vapor in the north direction of the Shaliu river basin in 2019 was earlier than that in 2017. The westward water vapor transportation shifted to the eastward water vapor transportation earlier,in 2017,the Shaliu river basin was affected by the westward water vapor transportation for a long time,and the transportation path was single.(3)The La Niña occurrence period in 2017 intensified the intensity of water vapor transportation in the west direction of the Shaliu river basin and shortened the time of water vapor transportation in the east direction;the occurrence of El Niño in2019 weakened the intensity of water vapor transport in the westward direction in the basin,increased the northward water vapor transport path,and extended the eastward water vapor transport time.