On the analysis of temporal geoid height variations obtained from GRACE-based GGMs over the area of Poland

Abstract

Temporal mass variations in the Earth system, which can be detected from the Gravity Recovery and Climate Experiment (GRACE) mission data, cause temporal variations of geoid heights. The main objective of this contribution is to analyze temporal variations of geoid heights over the area of Poland using global geopotential models (GGMs) developed on the basis of GRACE mission data. Time series of geoid height variations were calculated for the chosen subareas of the aforementioned area using those GGMs. Thereafter, these variations were analyzed using two different methods. On the basis of the analysis results, models of temporal geoid height variations were developed and discussed. The possibility of prediction of geoid height variations using GRACE mission data over the area of Poland was also investigated. The main findings reveal that the geoid height over the area of Poland vary within 1.1 cm which should be considered when defining the geoid model of 1 cm accuracy for this area.

Application of the PCA/EOF method for the analysis and modelling of temporal variations of geoid heights over Poland

“…1). Moreover, Godah et al (2017a) revealed that temporal variations of geoid heights obtained from RL05 GRACE-based GGMs developed by the CSR and JPL centres over the area of Poland are very similar to the corresponding ones of the GeoForschungsZentrum (GFZ) centre. The differences between temporal variations of geoid heights calculated from GGMs provided by these centres and the respective ones from the Water Global Assessment and Prognosis (WaterGAP) Global Hydrology Model (WGHM; Döll et al 2003) do not exceed 0.2 mm in terms of standard deviation values.…”

“…For this area the appropriate spatial resolution of RL05 GRACE-based GGMs filtered using the decorrelation (DDK3; see Kusche et al 2009) filter and truncated at degree/order 60 is about 3°9 3° (Godah et al 2017a). Thus, the area of the investigation has been divided into four subareas (Fig.…”

“…1.3 mm, and estimated standard deviations of these differences are 0.3-0.4 mm ( Table 3). The comparison between DN (PCA/EOF) and models of temporal variations of geoid heights presented in Godah et al (2017a) indicated that when using the PCA/EOF method for modelling temporal variations of geoid heights, the dispersion and the standard deviation of the differences can be reduced by 0.3-0.5 mm and 0.1-0.2 mm, respectively. Furthermore, the correlation coefficients between DN (GGM) and DN (PCA/EOF) are *1.1% higher than the corresponding ones indicated in Godah et al (2017b).…”

“…96.56-97.56%, with temporal variations of geoid heights computed using monthly RL05 GRACE-based GGMs. Moreover, Godah et al (2017a) illustrated the preference of seasonal component and trend (long term) component of temporal variations of geoid heights obtained with the use of the seasonal decomposition method for the prediction of temporal variations of geoid heights over the area of Poland.…”

On the estimation of physical height changes using GRACE satellite mission data – A case study of Central Europe

“…Several authors demonstrated the usefulness of the seasonal decomposition method and the PCA/EOF method for the analysis and modelling of time series of the functionals of functionals of the Earth gravitational fi eld (e.g. Rangelova, 2007;Krynski et al, 2014;Godah et al, 2017). The investigated methods can be described in short as follows:…”