#MATLAB 2009 FILTERS SERIES#

2012 Matsuo and Heki 2010 Yi and Sun 2014), groundwater storage depletion (Famiglietti et al. 2014 Velicogna and Wahr 2006a Velicogna and Wahr 2006b), mass balance in High Mountain Asia (Jacob et al.

2012), ice sheet mass balance in Antarctica and Greenland (Harig and Simons 2012 King et al. Numerous studies have demonstrated that GRACE has enabled many achievements in Earth science, e.g., terrestrial water storage (TWS) variations and relevant droughts and floods in the Amazon River basin (Chen et al.

The main products released by these data processing centers are level-2 GRACE solutions, i.e., geopotential fields in the form of spherical harmonic (SH) coefficients (Stokes coefficients), which can be used to interpret global gravity field changes and mass variations at the EarthвЂ™s surface. The GRACE observations are processed and released by the Center for Space Research (CSR) at the University of Texas at Austin, the Geo-Forschungs-Zentrum (GFZ) at Potsdam, the Jet Propulsion Laboratory (JPL), among others. Thus, by observing the distance between two satellites by the K-band ranging (KBR) instrument and orbit perturbations by GPS tracking, GRACE satellites can вЂњsenseвЂќ the gravity field and its variations in a direct way. Any mass variation at the EarthвЂ™s surface, in principle, causes the change of distance between two GRACE satellites, which is detected at micrometer precision. To measure the EarthвЂ™s gravity field from space, two GRACE satellites fly at an altitude of ~450В km in the same near-polar orbit with one 220В km ahead of the other. As a joint satellite mission between the National Aeronautics and Space Administration (NASA) and the German Aerospace Center (DLR), GRACE has proven to be an invaluable tool for monitoring the mass transport and redistribution in the EarthвЂ™s fluid envelopes with a footprint of ~300В km. Launched in March 2002, the Gravity Recovery and Climate Experiment (GRACE) satellite mission has provided direct observations of the global gravity field and its temporal variations with an unprecedented accuracy (Tapley et al.

We postulate that GRAMAT will also be an effective tool for the analysis of data from the upcoming GRACE-Follow-On mission. We conclude that using GRAMAT and processing the GRACE level-2 data products, the global spatio-temporal mass variations can be efficiently and robustly estimated, which indicates the potential wide range of GRAMATвЂ™s applications in hydrology, oceanography, cryosphere, solid Earth and geophysical disciplines to interpret large-scale mass redistribution and transport in the Earth system. In addition to obvious seasonal TWS variations in the Amazon River basin, significant interannual TWS variations are detected by GRACE using the GRAMAT, which are consistent with precipitation anomalies in the region.

As a case study, we analyze the terrestrial water storage (TWS) variations in the Amazon River basin using the functions in GRAMAT.

#MATLAB 2009 FILTERS SERIES#

Functions in GRAMAT contain: (1) destriping of SH coefficients to remove вЂњnorth-to-southвЂќ stripes, or geographically correlated high-frequency errors, and Gaussian smoothing, (2) spherical harmonic analysis and synthesis, (3) assessment and reduction of the leakage effect in GRACE-derived mass variations, and (4) harmonic analysis of regional time series of the mass variations and assessment of the uncertainty of the GRACE estimates. In this paper, we robustly analyze the noise reduction methods for processing spherical harmonic (SH) coefficient data products collected by the Gravity Recovery and Climate Experiment (GRACE) satellite mission and devise a comprehensive GRACE Matlab Toolbox (GRAMAT) to estimate spatio-temporal mass variations over land and oceans.

Matlab 2009 filters