Abstract
The substantial reliance of South Asia (SA) to rain-based agriculture makes the region susceptible to food scarcity due to droughts. Previously, most research on SA has emphasized the meteorological aspects with little consideration of agrarian drought impressions. The insufficient amount of in situ precipitation data across SA has also hindered thorough investigation in the agriculture sector. In recent times, models, satellite remote sensing, and reanalysis products have increased the amount of data. Hence, soil moisture, precipitation, terrestrial water storage (TWS), and vegetation condition index (VCI) products have been employed to illustrate SA droughts from 1982 to 2019 using a standardized index/anomaly approach. Besides, the relationships of these products towards crop production are evaluated using the annual national production of barley, maize, rice, and wheat by computing the yield anomaly index (YAI). Our findings indicate that MERRA-2, CPC, FLDAS (soil moisture), GPCC, and CHIRPS (precipitation) are alike and constant over the entire four regions of South Asia (northwest, southwest, northeast, and southeast). On the other hand, GLDAS and ERA5 remain poor when compared to other soil moisture products and identified drought conditions in regions one (northwest) and three (northeast). Likewise, TWS products such as MERRA-2 TWS and GRACE TWS (2002–2014) followed the patterns of ERA5 and GLDAS and presented divergent and inconsistent drought patterns. Furthermore, the vegetation condition index (VCI) remained less responsive in regions three (northeast) and four (southeast) only. Based on annual crop production data, MERRA-2, CPC, FLDAS, GPCC, and CHIRPS performed fairly well and indicated stronger and more significant associations (0.80 to 0.96) when compared to others. Thus, the current outcomes are imperative for gauging the deficient amount of data in the SA region, as they provide substitutes for agricultural drought monitoring.
Highlights
South Asia relies deeply on rain-fed subsistence agriculture, which is gradually becoming more susceptible to droughts [1–3]
The MERRA-2, Climate Prediction Center (CPC), FLDAS, Climate Hazard Group Infrared Precipitation with Stations (CHIRPS), and Global Precipitation Climatology Center (GPCC) data remained almost alike and constant over the entire four regions of South Asia; in the case of the ERA5 and Global Land Assimilation System (GLDAS) data, the spatial patterns of the standardized soil moisture indexes (SSMI) were dissimilar when compared to the other SM products (Figure 2)
In the case of the ERA5 and GLDAS data, the spatial patterns of the standardized soil moisture indexes (SSMI) were dissimilar when compared to the other SM products (Figure 2)
Summary
Sri Lanka) relies deeply on rain-fed subsistence agriculture, which is gradually becoming more susceptible to droughts [1–3]. South Asia (SA) is one of the most disaster-prone and densely populated regions in the world, comprising over one-fifth of the world’s population [4]. Population increases and frequent drought events have been leading issues that have furthered food shortages and water crises [5]. According to a recent study conducted by Zhai et al [6], a significant increasing trend of droughts has been recorded over SA. Strong increases in average drought frequencies and durations have been projected. About 31% of the agricultural lands of SA have been influenced by droughts during the past two decades, representing a severe hazard to the economic and social development of the region [10].
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
