Sea Level Change in the Arctic Ocean: Quantifying Contributions to Present-Day Arctic Ocean Sea Level Change
The Arctic Ocean is in the region with the fastest warming on Earth and is also the most inaccessible ocean in the world. Deglaciation of ice, ocean freshening, ocean warming changes the Arctic Ocean sea level and the relation to the global ocean circulation. Satellite measurements of Arctic sea lev...
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| Format: | Book |
| Language: | English |
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Technical University of Denmark
2020
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| Online Access: | https://orbit.dtu.dk/en/publications/37589ece-3764-4569-860f-6bb513fadeb8 https://backend.orbit.dtu.dk/ws/files/239923350/Dissertation_final_compressed_150920.pdf |
| Summary: | The Arctic Ocean is in the region with the fastest warming on Earth and is also the most inaccessible ocean in the world. Deglaciation of ice, ocean freshening, ocean warming changes the Arctic Ocean sea level and the relation to the global ocean circulation. Satellite measurements of Arctic sea level is challenged by varying sea ice and large ice mass changes on land. This PhD-thesis aims to quantify each of the contributions to sea level change in the Arctic Ocean and thereby improve the comprehension of the effects of climate change and validate sea level observations from remote sensing on the Arctic Ocean. Radar altimeters have observed sea level changes in the Arctic since 1991, but the sea ice cover significantly limits the observations. Challenges of separating younger sea ice and meltponds on top of ice from leads between sea ice floats and open ocean furthermore exacerbates altimetric observations, resulting in large discrepancies among products. Mass changes observed by the GRACE-satellites since 2002 are affected by large deglaciation on land that overshadows smaller changes in the ocean. Even though different procedures for separating changes on land and in ocean estimates of mass changes vary between 2 and 15 mm y −1 in the interior Arctic. To estimate sea level anomalies caused by changes in ocean salinity (halosteric) and temperature (thermosteric), studies often rely on the difference between GRACE and altimetry, which is an arguable approach considering the large ambiguity of the satellite products. In this study, an original approach is taken to create a satellite independent steric sea level product, called DTU Steric. From over 300k temperature and salinity profiles is a Arctic temperature and salinity grid compiled, which is used to compute steric changes. The product shows increased freshwater in the Arctic Ocean gives a significant sea level rise at the west coast of the Russian Arctic (10-20 mm y−1) and in the Beaufort Sea (10-15 mm y −1 ). Ocean warming causes a more uniform and smaller ... |
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