Author(s): Jae Young Seo; Sang-Il Lee
Linked Author(s):
Keywords: Terrestrial water storage; GRACE; Groundwater; GLDAS; WAMIS
Abstract: Terrestrial water storage (TWS) is defined as all forms of water stored above and below the earth’s surface. The GRACE twin satellite provides a direct method for assessing TWS by measuring the earth’s gravity value. Monthly gravitational variations are measured at 1.0°resolution, and equated to equivalent liquid water thickness data. Since GRACE-derived TWS is identical to the sum of mass of all forms of water, the amount of a specific water body (e.g., groundwater storage) can be calculated if other parts of the water balance equation are known. We used Level-2 (RL05) Gaussian filtered data with a radius of 300 km to calculate monthly TWS changes in South Korea for the period of January 2003 to December2012. Changes in groundwater storage (GWS) were calculated by subtract variations in soil moisture storage (SMS), snow water equivalent storage (SWES), and surface water reservoir storage (RESS) from the GRACE-derived TWS changes. Data needed for calculations were obtained from Global Land Data Assimilation System (GLDAS) and Water Management Information System (WAMIS). Groundwater storage changes were, on average, 0.015 cm/year. Validation is underway using the data from in situ groundwater observation wells. This remote sensing satellite-based method could provide an efficient tool for groundwater planning and management at the national scale.
Year: 2014