三江源区大气可降水量时空特征及其与降水关系  

Spatial-Temporal Characteristics and Relations of Precipitable Water Vapor with Precipitation in the Three Rivers Source Region

作　　者：强安丰 汪妮[1,2] 解建仓[1,2] 姜仁贵[1] QIANG Anfeng;WANG Ni;XIE Jiancang;JIANG Rengui(Institute of Water Resources and Hydroelectric Engineering,Xi'an University of Technology,Xi'an 710048,China;State Key Laboratory of Eco-Hydrologic Engineering in Northwest Arid Region of China,Xi'an University of Technology,Xi'an 710048,China)

机构地区：[1]西安理工大学水利水电学院,陕西西安710048 [2]西安理工大学省部共建西北旱区生态水利国家重点实验室,陕西西安710048

出　　处：《干旱气象》2019年第1期22-30,共9页Journal of Arid Meteorology

基　　金：国家重点研发计划项目(2016YFC0401409);国家自然科学基金项目(51679188;51509201);陕西省自然科学基础研究基金(2018JM5031)共同资助

摘　　要：利用1979—2016年欧洲中期天气预报中心(ECMWF) ERA-Interim (1°×1°)再分析资料中的经、纬向水汽通量和大气可降水量(precipitation water vapor,PWV)数据,采用相关性分析、趋势分析法、累积距平、IDW等方法,分析三江源地区PWV与水汽通量的时空分布特征、降水转化率(precipitati-on conversion efficiency,PCE)变化规律。结果表明:过去的38 a,经、纬向多年平均水汽通量分别为50. 2、196. 7 kg·m-1·s^(-1),纬向水汽通量气候倾向率比经向大。南边界为纬向主要水汽输入边界,东边界为经向主要水汽输出边界,纬向水汽输送大于经向输送。多年平均PWV为1998. 3 mm,近38 aPWV呈现微弱增加趋势,1979—1997年,PWV呈下降趋势,1998年后PWV呈增加趋势,同期降水也在增加,说明该时段三江源地区气候转湿。PWV与水汽通量的年际变化趋势和转折年相一致。三江源区多年平均PCE为24. 57%,1989年PCE最高,达32. 76%,各季节平均PCE空间分布与年平均PCE分布一致,均表现出南部、东南部高,西部、东北部低的变化特征,各季节PCE大小差异明显,春季多年平均PCE为15. 92%,夏季25. 67%,秋季21. 01%,冬季仅7. 03%。The spatial-temporal characteristics of precipitable water vapor and water-vapor flux as well as precipitation conversion efficiency in the Three Rivers Source region were discussed through correlation analysis,trend analysis,accumulative anomaly and inverse distance weight based on ERA-Interim reanalysis data(1°×1°)produced by the European Centre for Medium-Range Weather Forecasts(ECMWF)from 1979 to 2016.The results show that the mean meridional and zonal water vapor flux in the past 38 years were 50.2 and 196.7 kg·m^-1·s^-1,respectively.The climate tendency rate of zonal water-vapor flux was much higher than that of the meridional.The south boundary was the main zonal water-vapor input boundary and the eastern boundary was the main medidional water-vapor output boundary in the Three Rivers Source region,the zonal transport was larger than the meridional transport.The average annual precipitable water vapor was 1998.3 mm.The annual precipitable water vapor increased slightly from 1979 to 2016,it showed a downward trend from 1979 to 1997,and an increasing trend after 1998,and precipitation also increased during the same period.This phenomenon indicated that the climate in the Three Rivers Source region turned wet during this period.The interannual variation and the mutation year of annual precipitable water vapor was consistent with that of the annual water vapor flux.There were significant differences of precipitatable water vapor value in different seasons.The annual average precipitation conversion efficiency in the study area was 24.57%and it reached the peak(32.76%)in 1989.Spatial distribution of average precipitation conversion efficiency in four seasons was consistent with that of annual average value,they all showed the variation of high in the south and the southeast and low in the west and the northeast.Moreover,a great seasonal difference of precipitation conversion efficiency was recognized.The average precipitation conversion efficiency in spring was 15.92%,in summer it was 25.67%,in autumn it w

关 键 词：ECMWF 大气可降水量(PWV) 水汽输送 时空变化 降水转化率(PCE) 

分 类 号：P426[天文地球—大气科学及气象学]