基于干旱荧光监测指数的海河流域干旱监测研究

Drought Monitoring in Haihe River Basin Based on Drought Fluorescence Monitoring Index

摘要:

海河流域是我国重要的农业生产区，及时准确掌握干旱时空特征对农业水资源管理及粮食安全具有重要意义。基于日光诱导叶绿素荧光（Sun-induced chlorophyll fluorescence，SIF）、地表温度（Land surface temperature，LST）、降水量以及土壤湿度（Soil moisture，SM）数据，构建了综合考虑植被长势、温度、降水量以及土壤含水率的海河流域干旱荧光监测指数（Drought fluorescence monitoring index，DFMI），同时利用已有干旱指数和站点土壤含水率对其精度进行了评价，并利用趋势分析和游程理论等方法分析了2001—2021年该流域DFMI时空演变特征及其干旱频率、干旱历时和干旱强度等特征变量的空间分布。结果表明：DFMI与SM、自适应帕尔默干旱指数（Self calibrating Palmer drought severity index，scPDSI）、标准化降水蒸散指数（Standardized precipitation evapotranspiration index，SPEI）（1个月（SPEI01）、3个月（SPEI03）、6个月（SPEI06）、9个月（SPEI09）、12个月（SPEI12））的相关系数分别为0.58、0.64、0.73、0.52、0.44、0.47和0.49。与12个站点土壤含水率相关性均通过了0.05显著性水平检验，表明DFMI适用于流域干旱监测。2001—2021年海河流域DFMI年均值呈显著上升趋势，上升速率为0.009 7/a（p<0.05）。秋季上升速率最大（0.013 1/a，p<0.05），春季最小（0.007 7/a，p<0.05）。海河流域年DFMI呈现显著上升趋势（p<0.05）面积占比达99.18%，春季、夏季、秋季、冬季DFMI呈显著上升趋势面积占比分别为38.36%、63.42%、58.96%和50.26%，主要分布在流域西北部。2001—2021年海河流域干旱频次高发区域（30~37次）主要集中在流域南部，平均干旱历时高值区（5~10.2个月）主要集中在流域北部，干旱强度高值区（0.30~0.37）分布在流域中部和东南部。研究结果可为流域水资源管理及其防旱抗旱提供科学依据。

Abstract:

The Haihe River Basin is a crucial agricultural production region in China, and understanding the temporal and spatial characteristics of drought is vital for managing agricultural water resources and ensuring food security. Drought fluorescence monitoring index (DFMI) for the Haihe River Basin was constructed-based on the sun-induced chlorophyll fluorescence (SIF), land surface temperature (LST), precipitation, and soil moisture (SM). This index comprehensively integrated vegetation growth, temperature, precipitation, and soil moisture content to monitor drought conditions. At the same time, the accuracy of the DFMI was evaluated by using existing drought indices and soil moisture data from monitoring stations. Additionally, trend analysis and run theory were employed to analyze the temporal and spatial evolution characteristics of the DFMI in the Haihe River Basin from 2001 to 2021, as well as the spatial distribution of variables such as drought frequency, drought duration, and drought intensity. Results indicated that the correlation coefficients between DFMI and SM, self-calibrating Palmer drought severity index (scPDSI), standardized precipitation evapotranspiration index (SPEI) (SPEI01, SPEI03, SPEI06, SPEI09, SPEI12) were 0.58, 0.64, 0.73, 0.52, 0.44, 0.47 and 0.49, respectively. The correlation between DFMI and SM at 12 sites passed the 0.05 significance level test, indicating that DFMI was suitable for drought monitoring in the Haihe River Basin. The annual mean value of DFMI in the Haihe River Basin exhibited a significant increasing trend from 2001 to 2021, with an increase rate of 0.009 7/a (p<0.05). The highest increase rate was observed in autumn (0.013 1/a, p<0.05), and the lowest in spring (0.007 7/a, p<0.05). The annual DFMI in Haihe River Basin showed a significant upward trend (p<0.05), with 99.18% of the area exhibiting this trend. In spring, summer, autumn, and winter, the area showed a significant upward trend in DFMI accounted for 38.36%, 63.42%, 58.96%, and 50.26%, respectively, with most of these areas located in the northwest of the basin. From 2001 to 2021, areas with high drought frequency (30 to 37 times) were mainly concentrated in the southern part of the Haihe River Basin. Regions with high average drought duration (5 to 10.2 months) were found in the northern part, and areas with high drought intensity (0.30 to 0.37) were found in the central and southeastern parts of the basin. These findings can provide scientific evidence for water resource management and drought prevention and mitigation in the basin.