塔里木河流域Palmer指数的改进与评估

Evaluation and Improvement on Palmer Index of Tarim River Basin

利用塔里木河流域气象、水文和土壤资料改进了流域PDSI指数,分析比较了改进的PDSI和原PDSI监测流域干湿能力。结果表明,在该流域,年和四季改进的PDSI数值和等级变化比原PDSI的更接近NDVI的变化;改进后年、夏季和秋季PDSI与NDVI为正相关且相关性较高,春季和冬季的改进前后都为负相关,改进后年和四季的相关系数都高于原PDSI的,说明改进后PDSI在夏、秋季反映流域干湿的能力较强,改进前后在春、冬季都较弱。在流域大部分区域改进后年和四季PDSI与NDVI相关系数高于原PDSI的,说明改进的PDSI能更好地反映流域干湿的空间变化。在该流域,改进后年和四季PDSI与NDVI指数的相关和逐年变化吻合度都好于原PDSI的。与实际旱情比较,改进的PDSI正确监测干旱总年数要多于原PDSI的,改进的PDSI监测干旱漏报总年数、空报总年数和监测正确率都好于原PDSI的。因此改进后的PDSI能够更好地监测塔里木河流域的干湿状况。

The Palmer index of Tarim River Basin was improved by using meteorological,hydrological and soil data,and the abilities of improved Palmer index and original Palmer index monitoring drought / wetness were compared and analyzed. The results are as following : the values and grads of improved Palmer index are closed to NDVI index than that of original Palmer index in season and year,the correlations between year,summer and autumn improved Palmer index and NDVI index are positive and higher,while the correlations of improved and original Palmer in autumn and winter are negative,all the correlations of improved Palmer index are higher than the correlations of original Palmer index in year and season. These showthat the abilities of improved Palmer index monitoring drought / wetness are better than that of original Palmer index,and the abilities are good in year,summer and autumn,while it is weak in spring and winter. The correlations of improved Palmer index are higher than the correlations of original Palmer index in most basin area in year and season. This showthat the improved Palmer index can reflect the spatial variation of drought / wetness in Tarim River Basin better. The correlations and degree of coincidence of inter- annual variation between improved Palmer index and NDVI index are better than that of original Palmer index in year and seasons,by comparing the actual drought situation,the correct year total of improved PDSI monitoring drought is more than that of original PDSI,the miss year total,vacancy year total and correctness of improved PDSI monitoring drought is better than that of original PDSI,so the improved Palmer index can monitor the drought / wetness in Tarim River Basin better.