| Summary: | The Amundsen Sea (AS) sector in West Antarctica accounts for a significant proportion of Earth’s ice losses and is the largest contributor of Antarctica’s mass loss. To evaluate its contribution to global sea-level rise, we reconstruct the long-term continuous surface elevation changes (CSEC) record of the AS sector by using an improved least-squares plane fitting method (ILSPFM) to merge altimeter data from Envisat, ICESat, CryoSat-2, and ICESat-2 missions during 2003-2021. The accuracy of CSEC is improved by 25.9% using ILSPFM. The average rate of CSEC in the AS sector was -24.25 ± 0.48 cm yr -1 during 2003 to 2021. The largest signals of SEC are found over Pine Island, Thwaites, and Pope Glaciers, with the largest decline of SEC over Pope Glacier with a total SEC of -82.44 ± 7.21 m and an annual change rate of -4.34 ± 0.38 m yr -1 . The ridge between Pine Island and Thwaites Glaciers is found in the AS sector, indicating that the change of ice sheet is dynamic thinning and closely related to the topography and the distance from the grounding line. Compared with the surface temperature record, we find that the codirectional fluctuation in CSEC is delayed by three months. Meanwhile, there is an obvious change in precipitation leading SEC series as the phase arrow points straight down from the cross wavelet transform. Our new record shows that the AS sector thinned rapidly from 2003-2021 but decelerated from 2019-2021, and it was clearly correlated to the surface temperature, precipitation, and local terrain.
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