Dynamics of Greenland’s glacial fjords
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2016 Glacial fjords form conduits between glaciers of the Greenland Ice Sheet and the North Atlantic. They are th...
Main Author: | |
---|---|
Format: | Thesis |
Language: | English |
Published: |
Massachusetts Institute of Technology and Woods Hole Oceanographic Institution
2016
|
Subjects: | |
Online Access: | https://hdl.handle.net/1912/7965 |
id |
ftwhoas:oai:darchive.mblwhoilibrary.org:1912/7965 |
---|---|
record_format |
openpolar |
spelling |
ftwhoas:oai:darchive.mblwhoilibrary.org:1912/7965 2023-05-15T16:21:15+02:00 Dynamics of Greenland’s glacial fjords Jackson, Rebecca H. Greenland 2016-06 https://hdl.handle.net/1912/7965 en_US eng Massachusetts Institute of Technology and Woods Hole Oceanographic Institution WHOI Theses https://hdl.handle.net/1912/7965 doi:10.1575/1912/7965 doi:10.1575/1912/7965 Glaciers Fjords Thesis 2016 ftwhoas https://doi.org/10.1575/1912/7965 2022-05-28T22:59:34Z Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2016 Glacial fjords form conduits between glaciers of the Greenland Ice Sheet and the North Atlantic. They are the gateways for importing oceanic heat to melt ice and for exporting meltwater into the ocean. Submarine melting in fjords has been implicated as a driver of recent glacier acceleration; however, there are no direct measurements of this melting, and little is known about the fjord processes that modulate melt rates. Combining observations, theory, and modeling, this thesis investigates the circulation, heat transport, and meltwater export in glacial fjords. While most recent studies focus on glacial buoyancy forcing, there are other drivers – e.g. tides, local wind, shelf variability – that can be important for fjord circulation. Using moored records from two major Greenlandic fjords, shelf forcing (from shelf density fluctuations) is found to dominate the fjord circulation, driving rapid exchange with the shelf and large heat content variability near the glacier. Contrary to the conventional paradigm, these flows mask any glacier-driven circulation in the non-summer months. During the summer, when shelf forcing is reduced and freshwater forcing peaks, a mean exchange flow transports warm Atlantic-origin water towards the glacier and exports glacial meltwater. Many recent studies have inferred submarine melt rates from oceanic heat transport, but the fjord budgets that underlie this method have been overlooked. Building on estuarine studies of salt fluxes, this thesis presents a new framework for assessing glacial fjord budgets and revised equations for inferring meltwater fluxes. Two different seasonal regimes are found in the heat/salt budgets for Sermilik Fjord, and the results provide the first time-series of submarine meltwater and subglacial discharge fluxes into a glacial fjord. Finally, building on the ... Thesis glacier Greenland greenlandic Ice Sheet North Atlantic Sermilik Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) Greenland Woods Hole, MA |
institution |
Open Polar |
collection |
Woods Hole Scientific Community: WHOAS (Woods Hole Open Access Server) |
op_collection_id |
ftwhoas |
language |
English |
topic |
Glaciers Fjords |
spellingShingle |
Glaciers Fjords Jackson, Rebecca H. Dynamics of Greenland’s glacial fjords |
topic_facet |
Glaciers Fjords |
description |
Submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy at the Massachusetts Institute of Technology and the Woods Hole Oceanographic Institution June 2016 Glacial fjords form conduits between glaciers of the Greenland Ice Sheet and the North Atlantic. They are the gateways for importing oceanic heat to melt ice and for exporting meltwater into the ocean. Submarine melting in fjords has been implicated as a driver of recent glacier acceleration; however, there are no direct measurements of this melting, and little is known about the fjord processes that modulate melt rates. Combining observations, theory, and modeling, this thesis investigates the circulation, heat transport, and meltwater export in glacial fjords. While most recent studies focus on glacial buoyancy forcing, there are other drivers – e.g. tides, local wind, shelf variability – that can be important for fjord circulation. Using moored records from two major Greenlandic fjords, shelf forcing (from shelf density fluctuations) is found to dominate the fjord circulation, driving rapid exchange with the shelf and large heat content variability near the glacier. Contrary to the conventional paradigm, these flows mask any glacier-driven circulation in the non-summer months. During the summer, when shelf forcing is reduced and freshwater forcing peaks, a mean exchange flow transports warm Atlantic-origin water towards the glacier and exports glacial meltwater. Many recent studies have inferred submarine melt rates from oceanic heat transport, but the fjord budgets that underlie this method have been overlooked. Building on estuarine studies of salt fluxes, this thesis presents a new framework for assessing glacial fjord budgets and revised equations for inferring meltwater fluxes. Two different seasonal regimes are found in the heat/salt budgets for Sermilik Fjord, and the results provide the first time-series of submarine meltwater and subglacial discharge fluxes into a glacial fjord. Finally, building on the ... |
format |
Thesis |
author |
Jackson, Rebecca H. |
author_facet |
Jackson, Rebecca H. |
author_sort |
Jackson, Rebecca H. |
title |
Dynamics of Greenland’s glacial fjords |
title_short |
Dynamics of Greenland’s glacial fjords |
title_full |
Dynamics of Greenland’s glacial fjords |
title_fullStr |
Dynamics of Greenland’s glacial fjords |
title_full_unstemmed |
Dynamics of Greenland’s glacial fjords |
title_sort |
dynamics of greenland’s glacial fjords |
publisher |
Massachusetts Institute of Technology and Woods Hole Oceanographic Institution |
publishDate |
2016 |
url |
https://hdl.handle.net/1912/7965 |
op_coverage |
Greenland |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
glacier Greenland greenlandic Ice Sheet North Atlantic Sermilik |
genre_facet |
glacier Greenland greenlandic Ice Sheet North Atlantic Sermilik |
op_source |
doi:10.1575/1912/7965 |
op_relation |
WHOI Theses https://hdl.handle.net/1912/7965 doi:10.1575/1912/7965 |
op_doi |
https://doi.org/10.1575/1912/7965 |
op_publisher_place |
Woods Hole, MA |
_version_ |
1766009268931133440 |