Comment by adrian_b
2 years ago
Your computation is very wrong, as explained in the actual research paper and in another comment here. The water is not moved only from under the ground to the surface and the effect on the axis is not due to raising, but mainly to horizontal movement.
post calculation. You're effectively saying, that the movement is due to a change in the center of mass of the earth?
The calculations are in section 2, beneath Figure 2 in the HTML version of the paper.
Changes in terrestrial water (urn:x-wiley:00948276:media:grl65897:grl65897-math-0001) (e.g., Figure 2a) and oceanic (urn:x-wiley:00948276:media:grl65897:grl65897-math-0002) (Figure 2b) mass loads were converted to spherical harmonic (SH) coefficients of the geoid: urn:x-wiley:00948276:media:grl65897:grl65897-math-0003 (1) where urn:x-wiley:00948276:media:grl65897:grl65897-math-0004 is the Earth radius times water density, urn:x-wiley:00948276:media:grl65897:grl65897-math-0005 are latitude and longitude, urn:x-wiley:00948276:media:grl65897:grl65897-math-0006 are normalized associated Legendre polynomials and urn:x-wiley:00948276:media:grl65897:grl65897-math-0007 are load Love numbers. Using the combined mass fields, urn:x-wiley:00948276:media:grl65897:grl65897-math-0008 PM excitations (urn:x-wiley:00948276:media:grl65897:grl65897-math-0009, urn:x-wiley:00948276:media:grl65897:grl65897-math-0010) were computed from the degree 2 (urn:x-wiley:00948276:media:grl65897:grl65897-math-0011) order 1 (urn:x-wiley:00948276:media:grl65897:grl65897-math-0012) SH coefficients via (Chao, 1985; Seo et al., 2021): urn:x-wiley:00948276:media:grl65897:grl65897-math-0013 (2) urn:x-wiley:00948276:media:grl65897:grl65897-math-0014 in which M is the Earth mass, and C and A are Earth principal moments of inertia. urn:x-wiley:00948276:media:grl65897:grl65897-math-0015 and urn:x-wiley:00948276:media:grl65897:grl65897-math-0016 from Equation 2 include effects of rotational feedback. We then estimated monthly (urn:x-wiley:00948276:media:grl65897:grl65897-math-0017, urn:x-wiley:00948276:media:grl65897:grl65897-math-0018) changes from groundwater (storage on land and associated sea level change) plus the other sources (AIS, GrIS, glaciers, dams and soil moisture). urn:x-wiley:00948276:media:grl65897:grl65897-math-0019 and urn:x-wiley:00948276:media:grl65897:grl65897-math-0020 are mostly determined by terrestrial storage changes with minor contributions from corresponding sea level rise due to relatively uniform distribution of ocean mass as shown in Figure 2b.