Glacier Melting Effect on the Earth’s Rotation - Revisited

Monday, 15 December 2014
Sung-Ho Na1, Dork L Sahagian2, Tu-Hwan Kim1, Bong Gon Jo3, Ki-Deok Ahn4 and Young Hong Shin5, (1)Ajou University, Suwon, South Korea, (2)Lehigh University, Bethlehem, PA, United States, (3)Chonbuk National University, Jeonju, South Korea, (4)National Geographic Information Institute of Korea, Space Geodetic Observation Center, Sejong, South Korea, (5)Korea Inst. Geosci. & Mineral, Daejeon, South Korea
The direction of polar wander has recently been tilted eastward by several degrees. By direct calculation of Earth’s inertia tensor perturbation due to observed glacier mass changes (twenty year average), we found the yearly drift polar motion excitation as (ψ1, ψ2)=(1.00, 0.05) milliarcsec. This direction closely matches the observed pole drift, and we infer that glacier melting is the primary driver of the observed polar wander. Analysis of polar motion data indicates that a substantial portion of the observed eastward pole drift has occurred since the late 1990s, also consistent with the accelerated rate of glacier melting. The associated change in LOD due to average glacier melting for the last twenty years is estimated as +114 microsec, which implies total 0.42 s delay in UT1 for the same time span.