Assessment of temporal variations of orthometric/normal heights at proposed International Height Reference Frame sites using GRACE/GRACE-FO

Abstract

The objective of this research is to assess temporal variations of orthometric/normal height (ΔH/ΔH*) at proposed International Height Reference Frame (IHRF) sites. GRACE/GRACE-FO-based Global Geopotential Models were utilized to determine temporal variations of geoid/quasigeoid height (ΔN/Δζ) and time-dependent changes of ellipsoidal height (Δh) induced from the temporal mass loading at those sites. ΔH/ΔH* at each site were determined by combining ΔN/Δζ and Δh. The results reveal that ΔH/ΔH* at proposed IHRF sites cannot be considered negligible as peak-to-peak variation of ΔH/ΔH* can reach 81 mm, and secular variations of ΔH/ΔH* range from approximately –2 mm/year to 9 mm/year.