Numerical modeling of Atlantic hurricanes moving into the middle latitudes.
Hurricanes that form over the Atlantic Ocean very frequently migrate into the middle latitudes where they encounter very different oceanic and atmospheric conditions than in the tropics. Cool sea surface temperatures (SSTs) cause these storms to weaken and become thermodynamically decoupled from the...
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ftdalhouse:oai:DalSpace.library.dal.ca:10222/54772 2023-05-15T17:22:57+02:00 Numerical modeling of Atlantic hurricanes moving into the middle latitudes. Fogarty, Christopher T. Ph.D. 2014-10-21T12:35:00Z http://hdl.handle.net/10222/54772 eng eng Dalhousie University AAINR16681 http://hdl.handle.net/10222/54772 Physical Oceanography Physics Atmospheric Science Atmospheric Sciences text 2014 ftdalhouse 2021-12-29T18:11:26Z Hurricanes that form over the Atlantic Ocean very frequently migrate into the middle latitudes where they encounter very different oceanic and atmospheric conditions than in the tropics. Cool sea surface temperatures (SSTs) cause these storms to weaken and become thermodynamically decoupled from the ocean, while baroclinic atmospheric environments often cause them to transform into extratropical storms---a process known as extratropical transition (ET). The changing structure of these storms in the middle latitudes presents many unique forecasting challenges related to the increasing asymmetry in moisture and wind fields, and their potentially destructive nature. An examination of three such events over Eastern Canada---using a combination of observations and a numerical model---forms the foundation of this work, with an emphasis on applying the research to weather forecasting. The case studies include Hurricane Michael (2000), Hurricane Karen (2001) and Hurricane Juan (2003). Hurricane Michael intensified in a strongly-baroclinc environment and evolved into an intense extratropical storm over Newfoundland. Karen also underwent ET, but weakened quickly during its approach to Nova Scotia, while Hurricane Juan struck the province as a category-two hurricane, experiencing only marginal weakening over anomalously warm SSTs. In essence, these cases represent a cross section of the behavior of many tropical cyclones in this part of the world. Hindcast simulations are conducted for each event using the Canadian Mesoscale Compressible Community (MC2) model with a synthetic, observationally-consistent hurricane vortex used in the model's initial conditions. Sensitivity experiments are run for each case by modifying initial specifications of the vortex, model physics parameterizations, and surface boundary conditions like SST. In the case of Hurricane Juan, it is determined that the anomalously-warm SSTs played a significant role in the landfall intensity, while Hurricane Michael was not particularly sensitive to small anomalies of the SSTs. Experiments conducted on Hurricane Karen reveal that the storm's landfalling intensity is not particularly sensitive to its intensity prior to traversing the cool waters south of Nova Scotia. A significant improvement in the storm structure was observed in all three cases compared with numerical models that did not employ vortex insertion. Thesis (Ph.D.)--Dalhousie University (Canada), 2006. Text Newfoundland Dalhousie University: DalSpace Institutional Repository Canada |
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Open Polar |
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Dalhousie University: DalSpace Institutional Repository |
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ftdalhouse |
language |
English |
topic |
Physical Oceanography Physics Atmospheric Science Atmospheric Sciences |
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Physical Oceanography Physics Atmospheric Science Atmospheric Sciences Fogarty, Christopher T. Numerical modeling of Atlantic hurricanes moving into the middle latitudes. |
topic_facet |
Physical Oceanography Physics Atmospheric Science Atmospheric Sciences |
description |
Hurricanes that form over the Atlantic Ocean very frequently migrate into the middle latitudes where they encounter very different oceanic and atmospheric conditions than in the tropics. Cool sea surface temperatures (SSTs) cause these storms to weaken and become thermodynamically decoupled from the ocean, while baroclinic atmospheric environments often cause them to transform into extratropical storms---a process known as extratropical transition (ET). The changing structure of these storms in the middle latitudes presents many unique forecasting challenges related to the increasing asymmetry in moisture and wind fields, and their potentially destructive nature. An examination of three such events over Eastern Canada---using a combination of observations and a numerical model---forms the foundation of this work, with an emphasis on applying the research to weather forecasting. The case studies include Hurricane Michael (2000), Hurricane Karen (2001) and Hurricane Juan (2003). Hurricane Michael intensified in a strongly-baroclinc environment and evolved into an intense extratropical storm over Newfoundland. Karen also underwent ET, but weakened quickly during its approach to Nova Scotia, while Hurricane Juan struck the province as a category-two hurricane, experiencing only marginal weakening over anomalously warm SSTs. In essence, these cases represent a cross section of the behavior of many tropical cyclones in this part of the world. Hindcast simulations are conducted for each event using the Canadian Mesoscale Compressible Community (MC2) model with a synthetic, observationally-consistent hurricane vortex used in the model's initial conditions. Sensitivity experiments are run for each case by modifying initial specifications of the vortex, model physics parameterizations, and surface boundary conditions like SST. In the case of Hurricane Juan, it is determined that the anomalously-warm SSTs played a significant role in the landfall intensity, while Hurricane Michael was not particularly sensitive to small anomalies of the SSTs. Experiments conducted on Hurricane Karen reveal that the storm's landfalling intensity is not particularly sensitive to its intensity prior to traversing the cool waters south of Nova Scotia. A significant improvement in the storm structure was observed in all three cases compared with numerical models that did not employ vortex insertion. Thesis (Ph.D.)--Dalhousie University (Canada), 2006. |
author2 |
Ph.D. |
format |
Text |
author |
Fogarty, Christopher T. |
author_facet |
Fogarty, Christopher T. |
author_sort |
Fogarty, Christopher T. |
title |
Numerical modeling of Atlantic hurricanes moving into the middle latitudes. |
title_short |
Numerical modeling of Atlantic hurricanes moving into the middle latitudes. |
title_full |
Numerical modeling of Atlantic hurricanes moving into the middle latitudes. |
title_fullStr |
Numerical modeling of Atlantic hurricanes moving into the middle latitudes. |
title_full_unstemmed |
Numerical modeling of Atlantic hurricanes moving into the middle latitudes. |
title_sort |
numerical modeling of atlantic hurricanes moving into the middle latitudes. |
publisher |
Dalhousie University |
publishDate |
2014 |
url |
http://hdl.handle.net/10222/54772 |
geographic |
Canada |
geographic_facet |
Canada |
genre |
Newfoundland |
genre_facet |
Newfoundland |
op_relation |
AAINR16681 http://hdl.handle.net/10222/54772 |
_version_ |
1766109894144950272 |