甘肃省降水集中度的变化特征及其与环流指数遥相关分析  

Characteristics of Variation of Precipitation Concentration Index and Its Teleconnection Relationships with Large-scale Atmospheric Circulations in Gansu Province

作　　者：张克新 苏志华[1] 刘金林 曹立国 ZHANG Kexin;PENG Jiaoting;SU Zhihua;LIU Jinlin;CAO Liguo(School of Management Science and Engineering,Guizhou University of Finance and Economics,Guiyang 550025,China;School of Geography and Tourism,Shaanxi Normal University,Xi′an 710119,China)

机构地区：[1]贵州财经大学管理科学与工程学院,贵阳550025 [2]陕西师范大学地理科学与旅游学院,西安710119

出　　处：《水土保持研究》2021年第5期261-267,共7页Research of Soil and Water Conservation

基　　金：贵州省普通高等学校青年科技人才成长项目(黔教合KY字[2021]139);贵州省科技计划项目(黔科合基础-ZK[2021]一般189)。

摘　　要：降水的年内分配对作物生长、水资源利用和全球水循环具有重要的意义,而降水集中指数(Precipitation Concentration Index, PCI)能很好地表征降水在一年内的集中分散程度大小,被广泛应用于相关研究。基于甘肃省27个气象台站1961—2017年的逐月、逐日降水数据,采用Sen斜率来计算PCI值的变化趋势,并采用交叉小波和相干小波变换等方法来分析研究区PCI与若干气候环流指数之间的相互关系。结果表明:甘肃省多年平均PCI值为20.3,最大值为26.3(1980年)、最小值为16.6(2016年),表明年降水分布处于中高集中度范围。从长期趋势来看,研究区年PCI值呈下降趋势,变化递减率为-0.54/10 a;但年内降水还是集中在某几个月份内。甘肃省年平均PCI值的空间变化趋势由西北向东南逐渐增大,这说明东南部年降水呈现出逐渐趋于集中的趋势,而该地区西北部年降水分配却有逐渐趋于均匀的趋势。从四季来看,该区域春、夏、秋季的SPCI值空间分布格局基本一致,但空间差异明显,SPCI值呈现出东南部低而西北部相对较高的空间分布特征;冬季SPCI值在整个研究区域内空间变化差异最显著;说明甘肃东南部和中部地区的降水在冬季分布相对均匀,而西北部冬季降水具有高度集中性,也就是降水可能发生在某一个月内。交叉小波变换和小波相干谱分析表明:甘肃省年降水集中度与大气环流指数PDO,AO,ENSO和SS等存在共振周期,但相关性在不同时域中却存在一定差异,这说明该地区年PCI变化的重要因素之一是受到大气环流指数的影响。The precipitation concentration index(PCI) is a powerful indicator for temporal precipitation distribution and is also very useful for the assessment of seasonal precipitation changes. The primary objectives of this study are to investigate and analyze the temporal-spatial variability patterns of annual and seasonal PCI values based on monthly precipitation data. These data were collected from 27 meteorological stations located throughout Gansu Province, for the period of 1961—2017. Additionally, the possible teleconnection with the largescale circulation pattern was investigated. The results reveal that the variation trend of annual PCI values had decreased at a rate of-0.54/decade in Gansu Province over the past 57 years. The regularity of the annual precipitation pattern increased in spring, summer, and autumn from southeast to northwest of Gansu Province. However, the winter precipitation dispersion and the pattern in the considered period were more regular than those of the other seasons. Furthermore, the relationship between the PCI and PDO, AO, ENSO, and SS presented significant periodic variations with PCI, indicating that changes in the PCI appeared to be rather complex and possibly related to global atmospheric characteristics. These results presented in this study indicate that the PCI is an essential feature for water resource planning, prediction of risk due to droughts or floods, and the management of natural resources.

关 键 词：降水集中度 变化特征 大气环流 甘肃省 

分 类 号：P467[天文地球—大气科学及气象学]