| Seasonal drought characteristics based on relative moisture index in Yunnan Province |
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| DOI：10.7606/j.issn.1000-7601.2020.04.35 |
| Key Words: seasonal drought relative moisture index spatial and temporal distribution Yunnan Province |
| Author Name | Affiliation | | ZHANG Qingwen | China Forest Exploration and Design Institute on Kunming, Kunming, Yunnan 650216, China
State Key Laboratory of Hydraulics and Mountain River Engineering/College of Water Resource & Hydropower, Sichuan University, Chengdu , Sichuan 610065, China | | CUI Ningbo | State Key Laboratory of Hydraulics and Mountain River Engineering/College of Water Resource & Hydropower, Sichuan University, Chengdu , Sichuan 610065, China | | ZHAO Lushan | China Forest Exploration and Design Institute on Kunming, Kunming, Yunnan 650216, China | | XU Yang | China Forest Exploration and Design Institute on Kunming, Kunming, Yunnan 650216, China | | LI Qian | China Forest Exploration and Design Institute on Kunming, Kunming, Yunnan 650216, China | | LIU Feipeng | China Forest Exploration and Design Institute on Kunming, Kunming, Yunnan 650216, China |
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| Abstract: |
| In this study, daily climatic data from 31 meteorological stations in last 56 years (1961-2016) were used to calculate the relative moisture index (MI). Mann-Kendall test, GIS inverse distance weighted interpolation, and correlation coefficient method were used to analyze the distribution characteristics of meteorological drought in Yunnan. The results showed that: (1) The average annual MI in Yunnan Province was at -0.08, the average drought station ratio was 30.39%, and the intensity of annual drought increased. In winter, the MI value was the smallest at -0.73, and the ratio of drought stations was the highest at 52.58%. In summer, the MI was the largest at 0.69, and the ratio of drought stations was at the lowest (6.12%）. The intensity of spring drought showed a decreasing trend, while drought in summer, autumn, and winter showed an increasing trend. (2) On annual scale, they were all in the drought\|free level except for a few regions such as Huize and Zhanyi stations.In the spring, there were mainly moderate and light droughts, there was no drought in summer and autumn, and severe droughts were mainly in winter.In annual scale, the drought frequency increased from the Southwest to Northeast, with an average frequency of 54.9%.The frequency of spring drought in most regions was above 80%, and summer drought frequency was less than 20%. The autumn drought also showed a trend of lower in the Southwest and higher in the Northeast, with an average frequency of 35.6%, and an average winter drought frequency was at 92.6%. (3) Correlation analysis showed that the change of MI in Yunnan was significantly positively correlated with the precipitation and relative humidity (P<0.01). Sunlight hours had a very significant negative correlation with MI (P<0.01). The precipitation, relative humidity and sunlight hours were the main factors affecting MI change in Yunnan, while temperature had a smaller effect.This study can provide theoretical guidance for mitigating the seasonal drought impact and agricultural disaster reduction in Yunnan Province. |
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