Interplay of Altitude, Ground Track Coverage, Noise, and Regularization in the Spatial Resolution of GRACE Gravity Field Models

Abstract Models of the temporal gravity field derived from space missions are typically produced with monthly resolution and ∼300‐km spatial resolution. However, variations in instrument performance altitude Gravity Recovery Climate Experiment (GRACE) mission impact that can be achieved month‐to‐month. As orbits twin spacecraft vary throughout mission, so does ability observations to recover certain components field. The GRACE should increase as decreases because reduced intensifies signals acting on satellites. Simulations using actual ground track coverage realistic noise levels confirm this predicted influence satellites accuracy estimated solutions. Solutions larger mass concentration elements (mascons) more numerically stable satellite but they suffer greater error caused by inability properly represent within mascons, referred intramascon variability. Mascons small ∼150 × 150 km (i.e., ∼1.5 arc‐degree) reduce variability and, appropriate regularization, yield most accurate solutions, especially during low‐altitude periods mission. Importantly, unlike spherical harmonic regularized mascon solutions not degraded resonant orbit months, comparable quality months full coverage.