Assessing hydrological signal in polar motion from observations and geophysical models
Małgorzata Wińska , Justyna Śliwińska
AbstractChanges in Terrestrial Water Storage (TWS) due to seasonal changes in soil moisture, ice and snow loading and melting influence the Earth’s inertia tensor. Quantitative assessment of hydrological effects of polar motion remains unclear because of the lack of the observations and differences between various atmospheric and ocean models. We compare the effects of several hydrological excitation functions computed as the difference between the excitation function of polar motion Geodetic Angular Momentum (GAM) and joint atmospheric plus oceanic excitation functions, called geodetic residuals. Geodetic residuals are computed for different Atmospheric Angular Momentum (AAM) and Oceanic Angular Momentum (OAM) models and are analyzed and compared with the hydrological excitation function determined from the Land Surface Discharge Model. They are analyzed on decadal, interannual, seasonal and non-seasonal time scales. The equatorial components of hydrological geodetic excitation functions χ1 and χ2 are decomposed into prograde and retrograde time series by applying Complex Fourier Transform Models. The agreement between hydrological geodetic residuals and excitation functions is validated using Taylor diagrams. This shows that agreement is highly dependent on AAM and OAM models. Errors in these models affect the resulting geodetic residuals and have a strong impact on the Earth’s angular momentum budget.
|Journal series||Studia Geophysica et Geodaetica, ISSN 0039-3169, (A 15 pkt)|
|Publication size in sheets||1.15|
|Keywords in English||hydrological signal, polar motion, geophysical excitations of polar motion|
|Score|| = 15.0, ArticleFromJournal|
= 20.0, ArticleFromJournal
|Publication indicators||: 2017 = 0.823; : 2017 = 0.987 (2) - 2017=0.949 (5)|
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