The Emergence of Greenland Meltwater Impacts: From Boundary Currents to the Atlantic Overturning Circulation
The Greenland ice sheet has been steadily losing mass over the past decades from rising air temperatures and global warming. Additional freshwater input to the subpolar North Atlantic (SPNA) has the potential to reach areas where deep waters are formed, creating a lid of low salinity water resulting...
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| Other Authors: | , |
| Format: | Doctoral or Postdoctoral Thesis |
| Language: | English |
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Christian-Albrechts-Universität zu Kiel
2024
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| Online Access: | https://nbn-resolving.org/urn:nbn:de:gbv:8:3-2024-00771-8 https://macau.uni-kiel.de/receive/macau_mods_00005062 https://macau.uni-kiel.de/servlets/MCRFileNodeServlet/macau_derivate_00006397/thesis_Ilana.pdf |
| Summary: | The Greenland ice sheet has been steadily losing mass over the past decades from rising air temperatures and global warming. Additional freshwater input to the subpolar North Atlantic (SPNA) has the potential to reach areas where deep waters are formed, creating a lid of low salinity water resulting in a more strongly stratified layer. This could inhibit deep convection, potentially having future implications for the Atlantic Meridional Overturning Circulation (AMOC) and heat redistribution. This thesis aims to identify and quantify an emerging impact of enhanced Greenland meltwater runoff, at its current magnitudes, on hydrography and dynamics in the SPNA, by: (i) investigating the freshwater propagation and sources along the East Greenland shelf from 1993-2019 using high-resolution model output, reanalysis, and observations; (ii) further identify the impacts from enhanced meltwater input into the SPNA using a set of two twin model experiments with differing inputs of freshwater from Greenland; and (iii) investigate larger scale variability focusing on sea surface height anomalies and the relationship between differing AMOC strengths on decadal timescales, including the net effect of Greenland meltwater. This thesis provides new insights into the local impact of Greenland meltwater runoff and its current increase. While the signal is still relatively small, there are detectable hydrographic changes that occur primarily along the East and West Greenland boundary currents with potential for meltwater to reach deep convective sites. However it is too early to say if there additional Greenland runoff has influenced the strengh of the AMOC. There are still open questions to as what, how, and when Greenland meltwater may tip the freshwater balance of the SPNA. Thus it is important to continue monitoring freshwater changes using both observations and models. |
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