温度条件指数(TCI)在西南地区不同类型干旱监测中的适用性评估

Applicability Assessment of the Temperature Condition Index (TCI) for Drought Monitoring under Different Drought Types in Southwest China

摘要: 全球气候变暖背景下，中国西南地区干旱频发，严重威胁农业生产与生态安全。温度条件指数(TCI)是常用的热红外遥感干旱监测指标，但在复杂地形区的适用性尚不明确。本文基于2010~2022年MODIS地表温度数据计算TCI，以SPEI为参照，评估TCI在2010年降水连续亏缺型冬春连旱与2022年高温型极端干旱中的监测能力。结果表明：降水亏缺的2010年干旱中，TCI响应滞后明显，与灾情记录吻合度低；高温胁迫的2022年干旱中，TCI对热异常响应灵敏，能有效捕捉干旱演变过程。空间上，TCI在四川盆地及喀斯特山区精度较高，但在高植被区敏感性不足。总之，单一指数在西南地区不同干旱类型下表现差异显著，应根据主导胁迫因子(水分亏缺或热力异常)灵活选用或联合多指数监测。

Abstract: Under global warming, Southwest China experiences frequent droughts that severely threaten agricultural production and ecological security. The Temperature Condition Index (TCI), a commonly used thermal infrared remote sensing drought monitoring indicator, has unclear applicability in regions with complex terrain. Using MODIS land surface temperature data from 2010 to 2022, this study calculated TCI and, with reference to the Standardized Precipitation Evapotranspiration Index (SPEI), evaluated its monitoring capability for the 2010 precipitation-deficit autumn-winter drought and the 2022 high-temperature extreme drought. The results show that during the 2010 drought dominated by precipitation deficit, TCI exhibited a pronounced response lag and low consistency with disaster records. During the 2022 drought dominated by high-temperature stress, TCI responded sensitively to thermal anomalies and effectively captured the drought evolution process. Spatially, TCI achieved higher accuracy in the Sichuan Basin and karst mountainous areas, but showed insufficient sensitivity in densely vegetated regions. Overall, a single index performs markedly differently under different drought types in Southwest China; therefore, flexible selection or combination of multiple indices should be applied according to the dominant stressor (water deficit or thermal anomaly).