Abstract:
According to the definition of meteorological drought,considering exponential decay cumulative effect of drought,a daily meteorological drought indicator(SAPI*) is presented based on the antecedent precipitation index(API) and the standardized antecedent precipitation index(SAPI),and combined with the statistical methods of standardized time series.By analysising the applicability of SAPI* in Guizhou,the results are as follows:SAPI* is able to effectively describe the cumulative effect of drought during the 2009 to 2010 and 2011 in Guizhou,and to objectively reflect the occurrence,development and end of drought processes.Overcoming the unreasonable drought aggravation problem of the equal weight accumulation due to the antecedent precipitation moving out of the calculation window.The distribution characteristics of drought frequencies is able to describe the main period of time,which conclude the summer and spring.The more general drought is liable to appear in the rainless times and regions and the heavier and the heaviest drought is liable to appear in the rainy times and regions in Guizhou.Sensitivity analysis shows that the sensitivity of SAPI* for rainless days is higher,and for the amount of precipitation is also higher in Kaiyang station,where the rainless days is less and the precipitation is steadier,due to the development of drought is faster and the relief of drought is also faster,that is the reason for general drought probability is higher.Conversely,the sensitivity of SAPI* for rainless days is lower,and for the amount of precipitation is also lower in Xingyi station,where the rainless days is more and the precipitation is more concentrated,due to the development of drought is slower and the relief of drought is also slower,that is the reason for heavier and the heaviest drought probability is higher.