Determination and localized analysis of intersatellite line of sight gravity difference: Results from the GRAIL primary mission

摘要: [1] The line of sight (LOS) gravity difference between two coorbiting spacecrafts is determined in terms intersatellite range-acceleration measurements available from the Gravity Recovery and Interior Laboratory (GRAIL). The precise orbit data are crucial for retrieving range acceleration aligning LOS particularly altitude. A relative error a few centimeters position tens µm/s velocity commensurate with GRAIL-ranging instrument noise at μGal difference. power spectrum, as well topography correlation admittance, quantified by upward continuing topographic potential, forward modeling along spacecraft trajectory (i.e., Bouguer correction) comparing GRAIL observations. Based on analysis primary mission, I found that observation produced near unity potential out to degree 550, higher than global estimate, over areas covered low-altitude (~20 km). crustal density was estimated be 2500–2600 kg/m3 regional variations about 10%, minimizing coherence band 150–300. Systematic decrease estimates 3–4% or 100 observed shorter wavelengths (degree 300–500). It implies inadequacy uniform model across entire lithosphere suggests radial stratification bulk (or porosity). Due spatially localized characteristic, suited highest-possible resolution.