基于相对湿润指数的贵州省气象干旱时空变化特征研究

为探究贵州省各区域干旱发生频率、强度及不同等级干旱的时空分布特点,基于贵州省17个气象站1981—2019年逐日气象数据,利用相对湿润指数,同时结合Couple二维分布函数,探讨了干旱强度和干旱频率的联合、条件概率特征,以揭示贵州省气象干旱的时空分布规律。结果表明:(1)贵州省1981—2019年气象干旱强度呈减弱—增强趋势,整体上呈减弱的趋势,干旱频率呈上升趋势。(2)贵州省年与季尺度发生干旱强度在空间上分布有所不同,季尺度中,冬旱强度最强,秋旱和夏旱次之,春旱强度较弱;(3)年及冬、春季节干旱频率在空间上呈西高东低的分布格局,夏、秋季节分布较为一致; 季尺度中,干旱频率呈冬季最高,春、秋季次之,夏季最低;(4)在干旱联合特征中,季尺度的联合特征值呈春季>冬季>秋季>夏季,在各季节干旱强度的条件下,各季节干旱频率的条件概率特征值表现为夏季>秋季>冬季>春季。综上,贵州省气象干旱强度逐渐降低,干旱频发,呈春旱高频率、高强度,夏旱低强度、高频率。

Spatiotemporal Variation Characteristics of Meteorological Drought in Guizhou Province Based on Relative Humidity Index

In order to explore the spatial and temporal distribution characteristics of drought frequency, tensity and in different regions of Guizhou Province, based on the daily meteorological data of 17 meteorological stations in Guizhou Province from 1981 to 2019, the joint and conditional probability characteristics of drought intensity and drought frequency were discussed to reveal the spatial and temporal distribution of meteorological drought in Guizhou Province by using the relative humidity index, and combined with a Couple two-dimensional distribution function. The results show that:(1)from 1981 to 2019, the meteorological drought intensity in Guizhou Province showed a trend of weakening and increasing, and the drought frequency showed the increasing trend;(2)the spatial distribution of annual and seasonal drought intensity in Guizhou Province was different; at the seasonal scale, the winter drought intensity was the strongest, followed by autumn drought and summer drought, and the spring drought intensity was weak;(3)the spatial distribution pattern of drought frequency in year, winter and spring was higher in the west and lower in the east, and the distribution was more consistent in summer and autumn; at the seasonal scale, the drought frequency was the highest in winter, followed by spring and autumn, and the lowest in summer;(4)among the combined characteristics of drought, the combined characteristic values of the seasonal scale decreased in the order: spring>winter>autumn>summer; under the condition of drought intensity in each season, the conditional probability characteristic value of drought frequency in each season deceased in the order: summer>autumn>winter>spring. In conclusion, the intensity of meteorological drought in Guizhou Province gradually decreased, drought occurred frequently, spring drought was high frequency and high intensity, summer drought was low intensity and high frequency.