On the analysis of geodetic height changes obtained using different observation techniques at proposed IHRF sites

The determination of geodetic heights with high accuracy is one of the main tasks in geodesy. In 2015, a resolution for definition of International Height Reference System (IHRS) and its realization by International Height Reference Frame (IHRF) was released by the International Association of Geodesy (IAG). In the recent few years, intensive efforts have been devoted to develop the IHRF and its temporal changes. The main goal of the proposed study is to analyze temporal variations of geodetic height changes at the locations of proposed IHRF sites using data from Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE-FO) satellite missions, tide gauges, and space geodetic techniques, i.e. GNSS, SLR, VLBI, and DORIS.

Monthly GRACE/GRACE-FO-based Global Geopotential Models were utilized to estimate temporal variations of ellipsoidal height at proposed IHRF sites. Moreover, geodetic height changes were obtained from the aforementioned space geodetic techniques and tide gauge stations that co-located with the proposed IHRF sites. Then, the seasonal decomposition method and Discrete Fourier Transform were implemented to analyze time series of obtained geodetic height change. Based on the results, seasonal and long-term components of geodetic height variations at the proposed IHRF sites were determined, analyzed, and discussed according to the contemporary requirements for the definition of the IHRF, as well as the precise levelling measurements.

Keywords: GRACE/GRACE-FO satellite missions, space geodetic techniques, tide gauge, reference system/frame, geodetic height