| Abstract Submission No. | ABS-4.1-0117 |
| Title of Abstract | Recent Advances in Space Geodetic Observations for Terrestrial Water Storage Assessment in Major Indian River Basins |
| Authors | Vaska Lokesh*, Ravi Kumar Muppidi |
| Organisation | CSIR-National Geophysical Research Institute |
| Address | CSIR-NGRI hyderabad, TELANGANA, India Pincode: 500007 E-mail: vaskalokesh@gmail.com |
| Country | India |
| Presentation | Oral |
| Abstract | Recent advancements in space geodesy and remote sensing have enabled unprecedented insights into Earth¿s dynamic processes. Among these, the Gravity Recovery and Climate Experiment (GRACE) and its successor, GRACE Follow-On (GRACE-FO), have revolutionized monitoring of terrestrial water storage (TWS) variations by observing Earth¿s time-variable gravity field. These missions provide unique opportunities to track water mass exchanges across land, ocean, and ice. However, challenges remain in down-scaling coarse satellite products, integrating diverse datasets, and translating gravity signals into hydrologic variables of interest. This study investigates groundwater variability in the Ganga Basin, which has undergone significant depletion over the past two decades due to over-extraction, climate variability, and rising demand. In contrast, the Godavari, Krishna, and Mahanadi basins show relatively stable groundwater conditions. TWS changes from 2002¿2025 were derived using GRACE/GRACE-FO Level-2 Monthly Geo potential Spherical Harmonics (RL06.3) solutions of JPL, CSR, and GFZ and Degree-1 geocentric corrections, and GIA corrections (ICE6G-D) were applied. To reduce correlated errors and de striping, a 300 km Gaussian filter were applied, along with a 0.25° land grid mask. Our results were compiled with other hydrological datasets, including GLDAS, rainfall records, and groundwater well observations. Findings show persistent depletion in the Ganga Basin, especially in northwestern and central regions, strongly linked to rainfall decline and irrigation demand. In contrast, the other basins exhibit negligible loss. The improved sensitivity of GRACE-FO enhances detection of hydrological extremes and mass fluxes. Integrating gravimetry with modeling and ground observations demonstrates strong potential for early warning systems and future AI/ML-driven down-scaling to support sustainable groundwater governance in the Ganga Basin and beyond. |
| Keywords | GRACE, GRACE-FO, Ganga Basin, Groundwater depletion, Terrestrial water storage. |