ISSN 1000-0526
CN 11-2282/P
CN 11-2282/P
Archive > Volume 39 Issue 5 > 2013,39(5):600-607. DOI:10.7519/j.issn.1000-0526.2013.05.008 Prev Next
Study on Improvement of Drought Index Based on Effective Precipitation
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Abstract:
Based on the Weighted Average Precipitation (WAP), an improvement study on drought index was carried out in two aspects. After determining the two parameters of the WAP index and removing regional and seasonal differences, an improved WAP drought index named IWAP index was developed. Then, comparison analysis between IWAP index and Ci index was done. The results show that: IWAP index has a good correlation with Ci index in most of China especially in mid eastern China with correlation coefficients above 0.7 in most of Central China, most of Guizhou, southern Yunnan and southern Xinjiang. In identifying regional meteorological drought events, IWAP index also shows good consistency with Ci index on beginning time, ending time, impacted area and drought center. Further comparison of IWAP index, Ci index and anomaly percentage Pa index on drought processes for individual station shows that IWAP index is consistent with Ci index on beginning time while Pa index generally shows a delayed beginning time. However, the three indices all show good consistency on ending time. In addition, IWAP index shows a stable ability during a drought process while Ci index and Pa index tend to show unreasonable instability due to their algorithms. IWAP index also has some limitations, unsuitable to be applied in most of the Tibet Plateau and the regions with annual average precipitation less than 300 mm. IWAP index can be calculated in simple way and has clear physical meanings. Considering the nature that the index is only based on precipitation, IWAP index is not only convenient for meteorological operation, but also has obvious potential advantages in drought simulation and prediction in the case of limited output elements from current available climate models.
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