基于干旱K指数的阿勒泰地区夏旱风险区划

利用新疆阿勒泰地区7个气象站1981-2010年6-8月月平均气温、降水量资料，首先通过Thomthwaite方法计算潜在蒸发量确定K干旱指数，应用变异系数、风险概率、风险指数对阿勒泰地区夏季干旱的风险性进行了讨论和评估。结果表明：阿勒泰地区遭受干旱的风险性较高，出现偏旱的风险概率在80%左右，发生重旱的风险概率在22%～36%；综合风险区划结果显示：夏旱高风险区主要集中在阿勒泰北部和中东部，风险概率分布上偏北丘陵地区大于南部。

Risk Zone of Summer Drought in ALtay Area Based on Drought K index

Using the monthly average temperature and precipitation data that observed by seven weather stations in Altay area from June to August, from 1981 to 2010. The drought index, K , is determined firstly by calculating the potential evaporation through Thomthwaite method, the risk of the summer drought in Altay area were discussed and evaluated using the variation coefficient, the risk probability and risk index of the drought index （K）. The results show that the risk of the summer drought was high in Altay. The probability of precipitation less than normal in summer was about 80% and the probability of serious drought was 22%~36%. The results of the comprehensive risk division show that the high possibility of summer drought concentrated in the northern and middle easthern regions in Altay area, while the probability of risk decreased from the northern to southern Altay area.