Influence of AAM and OAM on the Universal Time Variations

Abstract

Atmospheric Angular Momentum (AAM) and Ocean Angular Momentum (OAM) function excite Length of Day (LOD) variations and affect Universal Time (UT1) variations at wide frequency band also, which appear as parasitical noise in some problems of parameters estimation. The influences of AAM and OAM on UT1 are determined by an integrating of the AAM and OAM excitation functions of LOD, after removing of their constant parts. The resulting series still contain significant linear trends for some intervals, due to relatively small systematic deviations from the total mean value of LOD excitation (less than 80 μs). The final UT1 corrections for AAM and OAM influences are determined by removing of the residual trends. The maximal AAM effect on UT1 variations is about 100 ms and 1–2ms for OAM series. The obtained time series have good consistency and their application yield more precise estimation of the periodical terms of the Earth rotation.