Assessing the evolution of soil moisture and vegetation conditions during the 2012 United States flash drought

Abstract

This study examines the evolution of several model-based and satellite-derived drought metrics sensitive to soil moisture and vegetation conditions during the extreme flash drought event that impacted major agricultural areas across the central U.S. during 2012. Standardized anomalies from the remote sensing based Evaporative Stress Index (ESI) and Vegetation Drought Response Index (VegDRI) and soil moisture anomalies from the North American Land Data Assimilation System (NLDAS) are compared to the United States Drought Monitor (USDM), surface meteorological conditions, and crop and soil moisture data compiled by the National Agricultural Statistics Service (NASS). Overall, the results show that rapid decreases in the ESI and NLDAS anomalies often preceded drought intensification in the USDM by up to 6 weeks depending on the region. Decreases in the ESI tended to occur up to several weeks before deteriorations were observed in the crop condition datasets. The NLDAS soil moisture anomalies were similar to those depicted in the NASS soil moisture datasets; however, some differences were noted in how each model responded to the changing drought conditions. The VegDRI anomalies tracked the evolution of the USDM drought depiction in regions with slow drought development, but lagged the USDM and other drought indicators when conditions were changing rapidly. Comparison to the crop condition datasets revealed that soybean conditions were most similar to ESI anomalies computed over short time periods (2-4 weeks), whereas corn conditions were more closely related to longer-range (8-12 week) ESI anomalies. Crop yield departures were consistent with the drought severity depicted by the ESI and to a lesser extent by the NLDAS and VegDRI datasets.

Gauging the Severity of the 2012 Midwestern U.S. Drought for Agriculture

“…As shown in the Figure 2, the drought development phase started in the reproduction stages, indicating the potential for significant impacts on the corn yield, as shown in the statistical data [2]. This highlights Previous studies from Hoerling et al [55] and Otkin et al [28] suggested the 2012 Great Plain drought belonged to a "flash drought", as it developed rapidly in May 2012 and had reached peak intensity by that August. The total duration of this drought event is only 4 months.…”

“…This means that the recovery phase did not occur, and the onset phase was still ongoing in the late months of 2011. Previous studies from Hoerling et al [55] and Otkin et al [28] suggested the 2012 Great Plain drought belonged to a "flash drought", as it developed rapidly in May 2012 and had reached peak intensity by that August. The total duration of this drought event is only 4 months.…”

“…The Palmer Z-index is similar to the PDSI, and reflects the departure of the meteorological conditions of a particular month from the average moisture climatology for that month, regardless of what has occurred in prior or subsequent months [18]. The VegDRI integrates satellite-based observations of vegetation conditions, climate data, and other biophysical information [19], and has shown considerable capability in US [28].…”

Effect of the revisit interval and temporal upscaling methods on the accuracy of remotely sensed evapotranspiration estimates

“…For example, reliable information about ET is essential for accurately forecasting weather and assessing the impacts of changing climate (Katul et al, 2012;Wang and Dickinson, 2012), monitoring and mitigating the adverse effects of extreme weather events such as drought (Anderson et al, 2007(Anderson et al, , 2011Otkin et al, 2016), and identifying and predicting the changes in both the biogeographical characteristics of ecosystems and the services they provide in response to changing environmental conditions (Hawkins and Porter, 2003;Kreft and Jetz, 2007;Midgley et al, 2002). However, as pointed out by Seguin and Itier (1983), Abdelghani et al (2008), and Anderson et al (2012), among others, perhaps the most important application of ET data is in providing information critical to satisfying the competing demands for scare water resources.…”

The Effect of the Dry Line and Convective Initiation on Drought Evolution over Oklahoma during the 2011 Drought

“…Many contributing factors drive drought evolution in the GP including persistent synoptic patterns (e.g., Namais, 1983, and [6][7][8][9]), teleconnection patterns and sea surface temperature anomalies (e.g., [10][11][12][13][14][15][16]), and surface-atmosphere coupling (e.g., [12,17,18]). Further, drought can persist at temporal scales spanning several years to decades, such as the "Dust Bowl" of the 1930s and intense drought during the 1950s, while also developing rapidly during the warm season over periods as short as a few weeks [19][20][21].…”