Study of the atmospheric pressure loading signal in very long baseline interferometry observations

Abstract

[1] Redistribution of air masses due to atmospheric circulation causes loading deformation of the Earth's crust, which can be as large as 20 mm for the vertical component and 3 mm for horizontal components. Rigorous computation of site displacements caused by pressure loading requires knowledge of the surface pressure field over the entire Earth surface. A procedure for computing three-dimensional displacements of geodetic sites of interest using a 6 hourly pressure field from the National Centers for Environmental Prediction numerical weather models and the Ponte and Ray [2002] model of atmospheric tides is presented. We investigated possible error sources and found that the errors of our pressure loading time series are below the 15% level. We validated our model by estimating the admittance factors of the pressure loading time series using a data set of 3.5 million very long baseline interferometry observations from 1980 to 2002. The admittance factors averaged over all sites are 0.95 ± 0.02 for the vertical displacement and 1.00 ± 0.07 for the horizontal displacements. For the first time, horizontal displacements caused by atmospheric pressure loading have been detected. The closeness of these admittance factors to unity allows us to conclude that on average, our model quantitatively agrees with the observations within the error budget of the model. At the same time we found that the model is not accurate for several stations that are near a coast or in mountain regions. We conclude that our model is suitable for routine data reduction of space geodesy observations.

Impact of Atmospheric and Oceanic De-aliasing Level-1B (AOD1B) products on precise orbits of altimetry satellites and altimetry results

“…However, these variations do not include non-tidal high-frequency atmospheric and oceanic mass variations that should be added to the gravity field model in order to compute orbits of the Earth orbiting satellite with high precision. Atmospheric gravity can be modelled using AGRA (Service of the atmospheric contribution to geopotential) 6-hourly fields (Kalnay et al 1996) and (Petrov & Boy 2004). Atmospheric and oceanic mass variations are provided by Gravity Recovery and Climate Experiment (GRACE) Atmospheric and Oceanic De-aliasing Level-1B (AOD1B) products routinely derived by GFZ German Research Centre for Geosciences and serving as a background model for GRACE as well for a wide range of satellite missions .…”

Search for the 531-day-period wobble signal in the polar motion based on EEMD

“…Since the pole tides have been removed, namely, CW, AW and the possible 531 dW signals caused by the polar motion have been removed from the gravity records, the residual 531 dW must be caused by some other sources. Here, we further consider the hydrological loading (global) effect except the atmospheric loading (global) and non-tidal ocean loading effects (Petrov and Boy, 2004). The two latter effects are the same possible sources that excite the 531 dW in PM series.…”

Estimation of crustal vertical movements due to atmospheric loading effects by GPS observations

“…The atmospheric pressure loading is calculated by Jean Paul Boy (Petrov & Boy, 2004) using ECMWF (European Centre of Medium-range Weather Forecasts) pressure data. The surface pressure is convolved using Green's functions to generate the deformation at each node of a 2.5 • × 2.5 • grid.…”

“…The details of the technique used to model the pressure loading effects by convolving the atmosphere data with the Green's function are well described in Petrov & Boy (2004).…”

“…Several studies trying to detect pressure loading signals in height estimates have been performed during the last ten years: Van Dam & Herring (1994), Mac Millan & Gipson (1994, Haas et al (1997), Scherneck (2000), Van Dam et al (2001) and Petrov & Boy (2004).…”