Characteristics of Large-Scale and Localized Droughts in the Gangetic Plains

The groundwater depletion over the past two decades in the Indo-Gangetic Plains has been extensively documented. On a smaller scale, the Bundelkhand sub-region (rectangular box in the Figure) has been experiencing an extended period of meteorological drought. In this region, as with a majority of the Gangetic Plains, the contribution of local evaporation is comparable to the moisture brought in from afar.  It is unclear whether the below-normal rainfall in this region is due to low-frequency climate variability or a result of a "negative" feedback loop in the regional hydrologic cycle where less rain leads to less soil wetness, which in turn leads to lower evaporation and less moisture available for rain. An analysis of this region's daily rainfall records from the past century shows that while most droughts in and around Bundelkhand coincide with larger-scale Indian monsoon droughts (Type-1 in the Figure), some appear to be localized (Type-2 in the Figure). In addition, our analysis shows that while north central India typically experiences a rainfall deficit in early July, western India often sees more than normal rainfall. We present our assessment of the causes of these droughts, including the role of local hydrology and potential large-scale drivers.