眉山市干旱特征分析

Analysis of Drought Characteristics in Meishan

摘要: 全球气候变暖背景下区域干旱灾害风险持续上升，眉山作为新时代“天府粮仓”首提地和四川核心粮食产区，分析其气象干旱演变规律对粮食安全防控具有重要意义。本文基于眉山市6个国家级气象站1966~2022年逐日降水观测数据，划分五类干旱和四个干旱等级，从降水时空分布、干旱与降水的响应关系，以及干旱频次、持续时间、强度等维度，系统分析了全市气象干旱特征。结果表明：(1) 眉山市降水呈西高东低空间格局，年内集中于5~9月，冬春枯水现象突出，年际变幅较大；(2) 年降水量与干旱频次呈显著负相关，但响应强度区域差异明显，以仁寿县相关性最强，洪雅县最弱；(3) 全市主导干旱类型为夏旱与冬干，干旱频次与持续时长呈“东高西低”分布，仁寿县、彭山区为高值区，洪雅县为低风险区；(4) 干旱等级以一般为主，较重及以上等级发生频率极低，但冬干中高强度干旱占比远高于其他季节，且东部县域更易发生重度、特重干旱。

Abstract: Against the background of global climate warming, regional drought disaster risk continues to rise. As the first-proposed site of the “Tianfu Granary” in the new era and a core grain-producing area in Sichuan, Meishan is of great significance to analyzethe evolution of meteorological drought for food security prevention and control. Based on daily precipitation observation data from six national meteorological stations in Meishan from 1966 to 2022, this study classified five types of drought and four drought levels, and systematically analyzed the characteristics of meteorological drought across the city from the perspectives of spatiotemporal precipitation distribution, the response relationship between drought and precipitation, as well as drought frequency, duration, and intensity. The results indicate that: (1) precipitation in Meishan exhibits a spatial pattern of high in the west and low in the east, concentrated within May to September annually, with prominent winter-spring dry seasons and large interannual variability. (2) Annual precipitation shows a significant negative correlation with drought frequency, but the response intensity varies considerably among sub-regions, with the strongest correlation in Renshou County and the weakest in Hongya County. (3) Summer drought and winter dryness are the dominant drought types in the city. Drought frequency and duration present a pattern with higher values in the east and lower values in the west. Renshou County and Pengshan District are high-value zones, whereas Hongya County belongs to the low-risk zone. (4) Drought levels are predominantly classified as mild, with the occurrence frequency of severe and higher levels being very low. However, the proportion of medium-to-high intensity droughts in winter dryness is much higher than in other seasons, and eastern counties are more prone to severe and extreme droughts.