ESI as a Predictor of Agricultural Yield Anomalies
The utility of the ESI for monitoring crop stress and predicting agricultural drought impacts on yields has been evaluated in several case studies in the United States, Brazil, Tunisia, and Europe using ALEXI driven by GOES- and moderate resolution imaging spectroradiometer (MODIS)-derived LST time differences (e.g., Anderson et al. 2015, 2016; Mladenova et al. 2017; Otkin et al. 2016). An example of the potential capability of ESI is highlighted during the 2012 flash drought in the central United States, when ESI and ESI RCI identified the area of largest corn-yield impacts early in the season (May), before significant drought appeared in the USDM or VegDRI (related to NDVI anomalies). The ESI also agreed with county observer data collected by the USDA National Agricultural Statistics Service (NASS), who recorded visual topsoil moisture and crop conditions as they degraded through the growing season. Following Anderson et al. (2015, 2016), the annual yield data serve as a proxy indicator of agricultural drought impacts and enable assessment of relative timing and strength of correlation with multiple drought indicators. ESI and ESI RCI performance will be assessed in comparison with standard global Prcp- and vegetation index-based drought indices to develop a better understanding of conditions and locations where ESI adds unique value as an early indicator of developing crop stress.