Using a Diagnostic Soil-Plant-Atmosphere Model for Monitoring Drought at Field to Continental Scales
Using a Diagnostic Soil-Plant-Atmosphere Model for Monitoring Drought at Field to Continental Scales
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DOI：
10.1016/j.proenv.2013.06.006
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发表时间：
2013
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影响因子：
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通讯作者：
Martha C. Anderson;C. Cammalleri;C. Hain;J. Otkin;X. Zhan;W. Kustas
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文献类型：
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作者：
Martha C. Anderson;C. Cammalleri;C. Hain;J. Otkin;X. Zhan;W. Kustas
干旱评估是一项复杂的工作，需要监测水文预算多个组成部分的不足之处。降水异常反映了地表供水的变异性，而土壤水分、地下水和地表水异常反映了水分储存的不足。相比之下，蒸散(ET)异常提供了独特而互补的信息，反映了作物实际用水量的变化--这是对植被健康的有用诊断。在这里，我们描述了一种基于实际与参考ET比率异常的遥感蒸发应力指数(ESI)。利用一个诊断土壤-植物-大气模拟系统从热遥感数据中提取实际蒸散量，该系统是由地球同步卫星测量的早晨陆地表面温度(LST)上升造成的。与植被指数相比，LST是一个响应相对较快的变量，有可能为反映在冠层温度上升中的作物胁迫提供早期预警。ESI的时空模式与美国干旱监测和基于标准降水的指数的模式进行了比较，显示出合理的一致性。然而，由于ESI不使用降水作为输入，它提供了对不断变化的干旱情况的独立评估，对于世界上数据稀少、缺乏密集雨量计和多普勒雷达网络的地区来说，它更便于携带。通过数据融合集成地球静止轨道和极地轨道系统的LST信息，ESI在现场尺度的水分应力传感方面具有独特的潜力，对产量估计和损失补偿工作具有潜在的好处。ESI通常是使用地球同步运行环境卫星的数据在美国大陆制作的，目前正在向北美和南美扩展。此外，非洲和欧洲正在利用第二代气象卫星平台的地面产品开发干旱和ET监测应用程序。
Drought assessment is a complex undertaking, requiring monitoring of deficiencies in multiple components of the hydrologic budget. Precipitation anomalies reflect variability in water supply to the land surface, while soil moisture, groundwater and surface water anomalies reflect deficiencies in moisture storage. In contrast, evapotranspiration (ET) anomalies provide unique yet complementary information, reflecting variations in actual water use by crops – a useful diagnostic of vegetation health. Here we describe a remotely sensed Evaporative Stress Index (ESI) based on anomalies in actual-to-reference ET ratio. Actual ET is retrieved from thermal remote sensing data using a diagnostic soil-plant-atmosphere modeling system forced by measurements of morning land-surface temperature (LST) rise from geostationary satellites. In comparison with vegetation indices, LST is a relatively fast-response variable, with the potential for providing early warning of crop stress reflected in increasing canopy temperatures. Spatiotemporal patterns in ESI have been compared with patterns in the U.S. Drought Monitor and in standard precipitation-based indices, demonstrating reasonable agreement. However, because ESI does not use precipitation as an input, it provides an independent assessment of evolving drought conditions, and is more portable to data-sparse parts of the world lacking dense rain-gauge and Doppler radar networks. Integrating LST information from geostationary and polar orbiting systems through data fusion, the ESI has unique potential for sensing moisture stress at field scale, with potential benefits to yield estimation and loss compensation efforts. The ESI is routinely produced over the continental U.S. using data from the Geostationary Operational Environmental Satellites, with expansion to North and South America underway. In addition drought and ET monitoring applications are being developed over Africa and Europe using land-surface products from the Meteosat Second Generation (MSG) platform.