Brown Bag Seminar

Space geodetic techniques have provided high-precision measurement of daily change in the Earth's spin rate -- characterized by the Length of Day (LOD) -- and the spin axis position relative to the crust, termed Polar Motion (PM). Before the advent of the space era, astronomers and geophysicists have inferred the change in LOD for the past three millennia from eclipse records and the PM for over a century from optical astrometry. In this talk, I will summarize our ongoing efforts to understand and disentangle various driving mechanisms of the Earth's rotation parameters across timescales and highlight the increasingly dominant role of modern climate change. By leveraging observations of Earth's surface mass distribution, state-of-the-art climatological and geophysical models, and emerging machine learning algorithms, we show that the sustained melting of glaciers and ice sheets not only alters the long-term drift direction of the spin axis but also exhibits a strong control in slowing down the spin rate. These findings have broad implications for constraining various geophysical and climatological processes and exploring their possible interactions.