1973—2020年甘肃河东夏半年降水变化特征及影响因素分析  

Variation characteristics and influencing factors of summer half-year precipitation in Hedong region of Gansu Province from 1973 to 2020

作　　者：曹彦超 焦美玲 秦拓 郭桐 CAO Yanchao;JIAO Meiling;QIN Tuo;GUO Tong(Qingyang Meteorological Bureau,Qingyang 745000,Gansu,China)

机构地区：[1]庆阳市气象局,甘肃庆阳745000

出　　处：《干旱区地理》2022年第6期1695-1706,共12页Arid Land Geography

基　　金：甘肃省气象局科研项目(MS2021-09,ZcMs2022-33);甘肃省科技计划资助项目(20JR5RM626)资助。

摘　　要：基于1973—2020年4—9月甘肃河东60个国家气象观测站的降水资料,采用经验正交函数分解、相关分析等方法,分析了不同量级降水的时空分布及变化特征,并讨论了气温、大尺度环流、地形等对夏季降水的影响。结果表明:(1)河东西部位于季风区最末端,气温变化对降水影响相对显著。其中甘南高原及以北山区海拔高度高,输入性水汽少,气候变暖对水循环的促进使降水量趋于增多。西部其他区域输入性水汽仍占主导地位,冷空气活动减弱使降水量趋于减少。(2)河东东部地形过渡平缓,降水受季风影响显著。1998年后Niño 3.4区(5°N~5°S、120°~170°W)海温转为负距平为主,随着季风增强及雨带北抬,降水量随之增长。(3)河东地区降水量年际变化的主要特征是所有站点同时增大或减小,但在拉尼娜年更容易出现东、西部降水反相变化的特征,太平洋年代际振荡负相位时西部地区降水增多,东部部分站点减少,北极涛动负相位时,东南部降水增多,西部部分站点减少。甘肃河东夏半年降水变化及影响分析,不仅为复杂地形下大气环流和气候变暖对降水变化影响的差异性研究提供参考,还将丰富季风区末端降水预测依据。The Hedong region of Gansu Province,China,is located in the convergence zone of the Qinghai-Tibet Plateau and Loess Plateau.The terrain is complex and diverse,and the altitude drop is up to 3961 m.The precipitation climate difference is obvious,and several studies have shown that the precipitation in this region exhibits different trends in recent years.This project is based on the precipitation data of 60 national meteorological stations in the Hedong region from April to September between 1973 and 2020.The temporal and spatial distributions and variation characteristics of total precipitation and precipitation of different magnitudes are analyzed using an empirical orthogonal function method,and the influence of temperature,large-scale circulation,topography,and other factors on summer half-year precipitation in different regions are investigated using a correlation analysis method.The results are as follows:(1)The western part of the Hedong region is located at the end of the East Asian monsoon region.Light rain and moderate rain account for the largest proportion of the total precipitation,and temperature changes have a significant impact on precipitation.The altitude of the Gannan Plateau and the northern mountain area is high,and the input water vapor is less.The promotion of climate warming on the local water cycle makes the precipitation tend to increase.The imported water vapor remains dominant in other regions in the western part,and the weakening of cold air activity makes the precipitation tend to decrease.(2)The eastern part of the Hedong region has a gentle terrain transition,and the precipitation is significantly affected by the East Asian monsoon.After 1998,the sea surface temperature in the Ni?o 3.4 area was primarily a negative anomaly.With the strengthening of the monsoon and the northward uplift of the Chinese rain belt,the precipitation in the eastern region increased.(3)The main feature of interannual variation in precipitation in the Hedong region is that all stations increase or decrease s

关 键 词：夏半年降水 时空变化 气温 环流指数 甘肃河东 

分 类 号：P426.6[天文地球—大气科学及气象学]