基于CCDC和LandTrend算法的衡邵干旱走廊气象干旱时空特征研究

Research on the Spatiotemporal Characteristics of Meteorological Drought in the Hengyang-Shaoyang Arid Corridor Based on CCDC and LandTrend Algorithms

干旱事件对生态资源、农业发展影响广泛。衡邵干旱走廊是湖南省水资源最少的地区,研究并揭示衡邵干旱走廊干旱时空分布特征,对于面临严峻干旱形势的衡邵干旱走廊具有重要的现实意义。基于衡邵干旱走廊1961—2020年的逐月降水数据、平均温度数据和土壤最大有效持水量数据,构建衡邵干旱走廊的自适应帕默尔干旱指数(SC_PDSI)和标准化降水蒸散指数(SPEI)表达其干旱特征,并结合CCDC、LandTrendr算法和干旱指数探究衡邵干旱走廊气象干旱长时序空间特征。结果表明:(1)SC_PDSI干旱指数比SPEI干旱指数更适应于衡邵干旱走廊在全球气候变暖背景下的干旱监测。(2)时间尺度上,SPEI指数和SC_PDSI指数在CCDC算法中月尺度变化检测曲线整体趋势一致,但SC_PDSI指数较SPEI指数细微震荡更显著,对于微小的干旱变化更为敏感。(3)空间尺度上,衡邵干旱走廊干旱中部比四周更具稳定性,说明干旱区域性明显。研究结果可为制定应对干旱的农业政策与生态资源的保护政策提供科学的参考依据。

Drought events have significantly affected ecological resources and agricultural development.The Hengyang-Shaoyang(Hereinafter referred to as Heng-Shao)drought corridor is the region with the least water resources in Hunan province.Researching and revealing the spatio-temporal distribution characteristics of drought in the Heng-Shao drought corridor holds substantial practical importance for areas facing severe drought situations.Based on monthly precipitation data,average temperature data,and maximum soil water holding capacity data from 1961 to 2020,an adaptive Palmer Drought Severity Index(SC_PDSI)and the Standardized Precipitation Evapotranspiration Index(SPEI)were constructed to characterize the drought features of the Heng-Shao drought corridor.Additionally,the combination of CCDC and LandTrendr algorithms with drought indices explores the long-term spatial characteristics of meteorological drought in the corridor.The results show that:(1)The SC_PDSI is more suited for drought monitoring in the Heng-Shao drought corridor under the global warming scenario than SPEI.(2)On a temporal scale,the trends of monthly variation in the SPEI and SC_PDSI detected by the CCDC algorithm are generally consistent.However,the SC_PDSI exhibits more significant minor fluctuations than SPEI and is more sensitive to slight drought changes.(3)On a spatial scale,the central part of the Heng-Shao drought corridor has more stability in drought conditions than its surroundings,indicating a clear regional specificity of drought.The findings provide a scientific reference for formulating agricultural policies to address drought and for the conservation of ecological resources.