Open AccessEffect of global mass conservation among geophysical fluids on the seasonal length of day variation
Author(s) -
Yan Haoming,
Chao Benjamin F.
Publication year - 2012
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.67
H-Index - 298
eISSN - 2156-2202
pISSN - 0148-0227
DOI - 10.1029/2011jb008788
Subject(s) - variation (astronomy) , earth's rotation , angular momentum , geophysics , atmosphere (unit) , atmospheric sciences , momentum (technical analysis) , polar motion , satellite , geology , physics , environmental science , geodesy , meteorology , astrophysics , astronomy , finance , quantum mechanics , economics
Geophysical fluids models for the atmosphere, ocean, and land hydrology usually do not properly enforce the conservation of mass either individually or collectively. Called the global mass balance (GMB) effect, these errors, if not corrected, will significantly affect the determination of the effect of geophysical fluids on the variation in the Earth's rotation rate or length of day (LOD). Here we analyze the seasonal budget of the excitation sources for LOD variation in comparison with corresponding observations. We find that (1) the combined mass‐induced excitations of LOD variation by geophysical fluids are brought to much better agreement with the observed upon accounting for the GMB effect; (2) the above can be further improved to almost perfect closure if the motion term of the atmospheric angular momentum (to be removed from the observed LOD variation in obtaining the mass‐induced LOD variation) is magnified by 7%, corroborating the finding of Chao and Yan (2010); and (3) the above quantities all agree remarkably well with the equivalent LOD variation determined via J 2 variation from satellite laser ranging observations, indicating the usefulness of the latter as an independent measurement for mass transports in the geophysical fluids.