Monday, April 05, 2021, 12:00PM - 1:00PM
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Earth’s spin axis wanders through the crust as mass is being constantly redistributed on Earth’s surface and within its interior. Astrometric and space geodetic techniques have tracked the spin axis movement, termed polar motion, for more than 120 years now. In this seminar, I use improved datasets and methods for constraining Earth’s surface and interior mass transport across timescales to show that the climate-driven surface mass distribution alone explains some of the main features of the observed polar motion. While polar ice sheets contribute significantly to driving the secular and multi-decadal signals, large-scale variability in global hydrology controls the interannual variability in polar motion. I will conclude by highlighting the implications of these findings in terms of constraining climatological (ice sheets, sea level, hydrology) and geophysical (glacial isostatic adjustment, mantle convection) processes.
Surendra Adhikari is a research scientist at JPL’s Earth Surface and Interior group. He works at the intersection of climate science (e.g., glacier mechanics, sea-level variability) and solid Earth geophysics (e.g., glacial isostatic adjustment, Earth’s gravitation and rotation). He is currently a member and co-investigator of the NASA Sea-level Change Team and the GRACE-FO Science Team. He is a recipient of the 2019 NASA Early Career Achievement Medal and the 2020 Charles Elachi Award.