Using Atmospheric Uncertainties for GRACE De-aliasing: First Results
In standard gravity field processing, short-term mass variations in the atmosphere and the ocean are eliminated in the so-called de-aliasing step. Up to now the background models used for de-aliasing have been assumed to be error-free. As the accuracy assessed prior to launch could not yet be achieved in the analysis of real GRACE data, the de-aliasing process and related geophysical model uncertainties have to be considered as potential error sources in GRACE gravity field determination. The goal of this study is to identify the impact of atmospheric uncertainties on the de-aliasing products and on the resulting GRACE gravity field models. The paper summarizes the standard GRACE de-aliasing process and studies the effect of uncertainties in the atmospheric (temperature, surface pressure, specific humidity, geopotential) input parameters on the gravity field potential coefficients. Finally, the impact of alternative de-aliasing products (with and without atmospheric model errors) on a GRACE gravity field solution is investigated on the level of K-band range-rate residuals. The results indicate that atmospheric model uncertainties are small in terms of the associated spherical harmonic coefficients. The effect in terms of K-band observation residuals is negligible compared to other modeling errors.
KeywordsGravity Field Orbit Determination Geoid Height Gravity Field Model Potential Coefficient
This study was conducted as part of the IDEAL-GRACE project with the support of the German Research Foundation (Deutsche Forschungsgemeinschaft) and within the SPP1257 priority program “Mass transport and Mass Distribution in the System Earth”. The International Graduate School for Science and Engineering of the Technische Universität München also supported this work.
- Dach R, Hugentobler U, Fridez P, Meindl M (eds) (2007) Bernese GPS software version 5.0. Astronomical Institute, University of Bern, BernGoogle Scholar
- ECMWF (2009) MARS user guide. Technical Notes, p 5. http://www.ecmwf.int/publications/manuals/mars/guide/MarsUserGuide.pdf. Accessed date 17 August 2011
- Flechtner F (2007) AOD1B product description document. GRACE project documentation, JPL 327–750, Rev. 1.0. JPL, Pasadena, CA. 17 August 2011Google Scholar
- Jäggi A, Beutler G, Meyer U, Prange L, Dach R, Mervart L (2011) AIUB-GRACE02S: status of GRACE gravity field recovery using the celestial mechanics approach. In: Kenyon S et al (eds) Geodesy for planet earth. Springer, HeidelbergGoogle Scholar
- Kim J (2000) Simulation study of a low-low satellite-to-satellite tracking mission. Technical report, University of Texas at Austin, Austin, TXGoogle Scholar