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Stripe Mystery in GRACE Geopotential Models Revealed
Author(s) -
Peidou Athina,
Pagiatakis Spiros
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2019gl085497
Subject(s) - geodesy , geopotential , geoid , geology , parallels , gravitation , sampling (signal processing) , nyquist frequency , physics , latitude , geophysics , computer science , classical mechanics , optics , bandwidth (computing) , mechanical engineering , computer network , detector , engineering , measured depth
The Gravity Recovery and Climate Experiment (GRACE) gravitational models suffer from a dominant systematic error, usually referred to as “longitudinal stripes.” These stripes contaminate useful geophysical signals and limit the spectrum of geoscience applications that can be benefited from GRACE and GRACE‐Follow On. Analyses of the spatiotemporal structure of latitudinal stripe profiles show consistent spectral characteristics throughout three years of monthly solutions. Using an elegant combination of GRACE sampling characteristics and advanced moiré theory, we show that the GRACE stripes are sub‐Nyquist (pseudo‐moiré) artifacts arising from the oversampling of the Earth's low‐frequency static disturbing potential (geoid) along the parallels. The low‐frequency geoid modulates the total sampled gravitational signal with a frequency near m n f s , where f s is the sampling frequency of the GRACE ground track “bundles” along the parallels of latitude, and m and n are mutually prime integers, with 2 m ≤ n .