基于条件植被温度指数的四川盆地干旱监测研究

The study on drought monitoring in the Sichuan Basin based on vegetation temperature condition index

关键词:  条件植被温度指数  干旱监测  归一化植被指数  地表温度  四川盆地

Key words:  vegetation temperature condition index  drought monitoring  normalized difference vegetation index  land surface temperature  the Sichuan Basin

摘要:

【目的】近年来,受全球气候变化影响,四川盆地干旱灾害呈现频率升高、持续时间延长、影响范围扩大的趋势,对区域粮食安全构成严峻挑战。由于该区域特有的多云雾特征,以及传统干旱监测手段存在局限,因此应用遥感技术准确地监测和评估四川盆地的干旱情况,对于提升防灾能力和减少灾害损失至关重要。【方法】本研究选取2014—2023年7—9月的Aqua-MODIS数据计算旬尺度条件植被温度指数(VTCI)并结合干旱等级划分标准和频数统计结果定性、定量分析四川盆地的旱情。此外,基于累计降水量与VTCI的相关性分析验证干旱结果的可靠性。【结果】(1)四川盆地旱情的时空分布呈现出明显差异。空间上,研究区域东南部旱情比较严重；时间上,7月下旬、8月上旬以及9月下旬旱情较为严重。(2)VTCI与累计降水量有较强的相关性,展现出可靠的干旱监测能力。【结论】2022年7—9月四川盆地发生严重干旱,8月旱情加剧；VTCI是可靠的干旱监测指数。

Abstract:

[Purpose] In recent years, the increasing frequency of drought events in the Sichuan Basin have profound impacts on local agricultural production, water resource management, and ecological environmental protection. However, the Sichuan basin is also characterized by frequent cloud cover and fog, making it challenging to accurately monitor and assess drought conditions using conventional methods. Therefore, accurately monitoring and assessing drought conditions in the Sichuan Basin is crucial for enhancing capacity for preventing disasters and mitigating the losses caused by drought disasters. [Method] This study selected Aqua-MODIS data from July to September of the years from 2014 to 2023 to calculate vegetation temperature condition index (VTCI), and qualitatively and quantitatively analyzed the drought condition in the Sichuan Basin based on drought categories and frequency statistical results. In addition, the correlation analysis between cumulative precipitation and VTCI was used to verify the reliability of VTCI for drought monitoring. [Result] The results showed that: (1) The spatiotemporal distribution of drought conditions in the Sichuan Basin exhibited differences. Spatially, the southeastern part of the study area experienced more severe drought conditions; and temporally, drought conditions were more severe in late July, early August, and late September. (2) VTCI showed a strong correlation with cumulative precipitation, which demonstrated a reliable drought monitoring capability. [Conclusion] Severe drought occurred in the Sichuan Basin from July to September in 2022, and the drought condition was aggravated in August. In addition, VTCI is a reliable drought monitoring index.