A Schematic Model to Approximate Spatial Leakage Effects in Satellite Gravimetry

Leakage effect is one of the main sources of error limiting the satellite gravimetry data application in continental hydrology. Leakage rate is affected by several factors which are defined by the gravimetry data structure and by the study unit specifications. Continental hydrology usually deals with isolated study units of various surface area and geometric shapes (e.g., watersheds, lakes, and groundwater basins). Several studies have investigated the leakage effect for a specific study unit. However, there is a lack of a general method to estimate the signal contamination by leakage effects, for study units. In this study, by analyzing the principal factors causing leakage effect, we have modeled the scaling factor in order to compensate leakage effects. Necessary information includes the degree of spherical harmonic truncation, latitude, and area and shape of the study unit. Each factor is studied separately using fitting approach; then, integrated effects from different combinations are discussed. The importance and priorities are determined based on leakage factors separately and for factor combinations. Consequently, this study provided a schematic model allowing approximate leakage effect on satellite gravimetry signal for any arbitrary study units. This model allows users to select the data kind and decide on area and shape of the study unit in order to optimize leakage effects within their studies.