3种干旱指标在陕西黄土高原的应用对比分析

为了提高干旱监测的准确性，实现气象干旱国家标准提供的干旱监测指数在陕西黄土高原地区的应用，运用陕西黄土高原地区68个气象站1971—2010年逐月气温和降水资料，采用累积频率法对3种干旱指标的阈值进行修正，并利用历史上出现的旱灾实况进行了指标的对比分析。结果表明：3种干旱指标监测的年干旱演变趋势基本一致，干旱站次数出现多的年份与当地历史典型大旱年记录非常吻合。对同一次干旱过程，干旱监测结果基本一致。订正后的指标解决了SPI监测结果偏重，而Ci偏轻的不足，对Pa按照降水量的年内变化特征，分区域逐月给出订正指标，监测结果更加客观地反映旱情状况。

Application of 3 Drought Evaluation Indices of the Loess Plateau in Shaanxi Province

In order to improve the accuracy of drought monitoring, to achieve national standards for providing meteorological drought index for drought monitoring the application of the loess plateau in Shaanxi, based on the monthly temperature and precipitation data at 68 meteorological stations of the loess plateau in Shaanxi Province during 1971-2010, the author adopted a cumulative frequency method to correct the threshold of three drought indices, and then used the drought live on history to analyze the indices. The results showed that: the evolution trends of the yearly drought were basical consistent, the years with many drought stations were in accordance with the typical drought years in history of the loess plateau in Shaanxi Province. On the same arid process, the drought monitoring results were basically the same. The corrected indices solved the shortcoming of monitoring results of the heavier SPI and the lighter Ci. And according to the characteristic of precipitation variability during the year, to correct the regional Pa index monthly. Monitoring results more objectively reflected the drought situation.