干旱指数及其在青海东部旱区特征分析上的应用

Analysis on the application of drought index in the dry-farming region of east Qinghai

在土壤水分平衡关系分析的基础上,提出了分析和评估旱害的5项指标:贫水指数、凋萎指数、降水指数、综合指数和干旱指数,并依据干旱指数对乐都浅山地区1961～1999年的粮食生产进行了年型分类。结果为:39a间共发生特大旱1a,大旱年3a,中旱年19a,轻旱年11a,平水年5a;发生机率分别为2.6%、7.69%、48.72%、26.21%、12.82%。同时认为青海东部地区旱区作物需水和耗水参数矛盾突出,干旱几乎年年发生,具有明显的难以预测性、多变性和不可控性。

Based on the analysis of soil water equilibrium relationship, this thesis brings forward 5 drough evaluation indices: water deficiency index, withering index, water consumption index, comprehensive index and drought index. Using the drought index, the crop production in Ledou mountainous area during 1961~1999 is classified. The results show that the frequency of extremely heavy drought, heavy drought, middling drought, light drought and rainy year was 1 a, 3 a, 19 a, 11 a and 5 a respectively, and the corresponding probability was 2.6%, 7.69%, 48.72%, 26.21% and 12.82%. In the dry-farming region of east Qinghai, there is anextrusive inconsistency between crop demand and water consumption, and the occurrence rate of drought disasters is very high, which is changeful and is difficult to forecast and control.