青海湖北部地区春季干旱分析及预测

Analysis and Prediction of Spring Drought in North Region of the Qinghai Lake

通过对海晏、门源等6个测站1979-2008年3～5月逐月降水、连续无降水日数、0～50cm的土壤相对湿度等资料的统计分析,从春旱发生的频率、强度寻找出春旱发生的规律,同时从春旱的气候特征、环流特征以及气温、海温等方面阐述了春旱的成因。对不同等级的春旱,利用相关分析和多因子组合,确定了春旱的预测指标(预测指标已纳入"青海省海北灾害性天气指标研究系统"中),并在2009年春季干旱预报中进行了应用。

In this paper,the meteorological data observed by 6 meteorological stations in north region of the Qinghai Lake are analyzed by using data of monthly precipitation,continuous days without precipitation,moisture content in soil layer of 0-50 cm,etc.during the period from 1979 to 2008,and the formation causes of spring drought are lucubrated from the factors related to spring drought,such as the frequency and intensity of spring drought,climatic and circulation characteristics,air temperature,lake water temperature,etc.The correlation analysis and the multi-factor combination are used to determine the prediction indexes of spring drought with different levels.The results are as follows：（1） Slight drought,moderate drought and serious drought occur every 3-4,6-7 and 8-9 years in the study area;（2） The occurring frequency of spring drought is holistically decreased;（3） The occurring frequency of spring drought in the south is higher than that in the north of the study area.The occurring frequency of spring drought is the highest,and the intensity of spring drought is the most serious in Gangcha;（4） There is a significant negative correlation between spring drought and monthly precipitation in previous September and October,especially in the south.The prediction indexes have been put into the＂Study System of Disaster Weather Indexes in the Haibai Region,Qinghai Province＂,and they were used in predicting spring drought in 2009.