Spatiotemporal Variability of Water Storage Anomalies and Soil Moisture Dynamics Across India's Diverse Hydroclimatic Zones: A Two-Decade Assessment Using GRACE and GLDAS

Vihaan Singla

Abstract: India faces increasing water stress due to climate variability, population growth, and unsustainable groundwater extraction, necessitating comprehensive monitoring of water resources across diverse hydroclimatic zones. This study presents a novel integrated analysis of terrestrial water storage (TWS) anomalies from GRACE satellites and soil moisture variations from Noah-GLDAS model spanning two decades (2003-2023), examining seasonal and interannual patterns at three critical time points: pre-monsoon (May), monsoon (July), and post-monsoon (October). Unlike previous studies focusing on single data sources or shorter timeframes, we synthesize gravitational and hydrological model outputs to capture both deep groundwater and surface moisture dynamics across India's complex hydrological landscape. Our analysis reveals stark spatiotemporal contrasts, with northwestern India exhibiting persistent negative TWS anomalies (-30 to -40 cm) indicating severe water depletion. While examining entire India, Delhi emerged as a critical hotspot, consistently showing extreme water depletion and soil moisture deficits across all seasons, reflecting intense urban water stress. The Indo-Gangetic plains demonstrated strongest seasonal amplitude, transitioning from severe pre-monsoon deficits to monsoon surpluses exceeding +35 cm. Soil moisture patterns corroborated TWS trends but showed faster response times, particularly in peninsular India where post-monsoon depletion occurred 1-2 months earlier than TWS changes. We identified intensifying hydrological extremes, with drought years (2008, 2018) and flood years (2013, 2023) showing unprecedented anomaly magnitudes. These findings provide crucial insights for sustainable water management, particularly for urban centres like Delhi requiring immediate intervention. The demonstrated predictive relationship between soil moisture and TWS anomalies offers potential for developing early warning systems, supporting India's water security goals and climate adaptation strategies for 1.4 billion people.

Keywords: water stress, terrestrial water storage, soil moisture variability, climate adaptation, sustainable water management

How to Cite?: Vihaan Singla, "Spatiotemporal Variability of Water Storage Anomalies and Soil Moisture Dynamics Across India's Diverse Hydroclimatic Zones: A Two-Decade Assessment Using GRACE and GLDAS", Volume 15 Issue 2, February 2026, International Journal of Science and Research (IJSR), Pages: 151-161, https://www.ijsr.net/getabstract.php?paperid=SR251028130626, DOI: https://dx.doi.org/10.21275/SR251028130626