基于干土层厚度的青海东部浅山农业区春季干旱规律及预测

Drought pattern and forecasting in shallow-mountain agricultural area in the east part of Qinghai: Analysis of dry-soil depth

利用青海东部浅山农业区10个站点1989～2002年的干土层厚度定位监测资料，分析了春季干旱的发生规律。结果表明：东部浅山农业区春季各地均有干旱发生，干旱发生时间在2～4月之间。尤以2～3月最多，春季干旱以轻度干旱为主，中度干旱次之，发生重度干旱的概率最小，作物播种越早，受干旱威胁越大。干旱发生概率随时间变化有高～低～高和高～低两种类型。土壤干土层变化与旬降水量的相关关系显著，可以直接建立降水与土壤干土层厚度的预报关系式，在2003年的资料检验中效果较好。

The spring drought pattern in shallow-mountain agricultural area in East Qinghai from 1980 to 2002 is analyzed by using dry-soil depths data of 10 meteorological stations. The results indicate that spring drought is pervasive in all regions of this area. The spring drought always occurs during February to April, and especially appears in February and March. The light drought is primary in this area, secondly is the moderate drought, and the probability of severe spring drought is seldom. The earlier the crops are planted, the higher drought risk they will suffer. The time course of drought pattern probability shows two types of high-low-high, and high-low. The dry-soil depth correlated significantly with 10-day precipitation. Therefore the prediction relationship of dry-soil depth and precipitation can be established. The prediction relationship verified preferably by meteorological data in 2003.