The role of heat-flux–temperature covariance in the evolution of weather systems
Local diabatic heating and temperature anomaly fields need to be positively correlated for the diabatic heating to maintain a circulation against dissipation. Here we quantify the thermodynamic contribution of local air–sea heat exchange on the evolution of weather systems using an index of the spat...
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Online Access: | https://doi.org/10.5194/wcd-1-701-2020 https://wcd.copernicus.org/articles/1/701/2020/ |
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ftcopernicus:oai:publications.copernicus.org:wcd85343 2023-05-15T17:33:18+02:00 The role of heat-flux–temperature covariance in the evolution of weather systems Marcheggiani, Andrea Ambaum, Maarten H. P. 2020-11-10 application/pdf https://doi.org/10.5194/wcd-1-701-2020 https://wcd.copernicus.org/articles/1/701/2020/ eng eng doi:10.5194/wcd-1-701-2020 https://wcd.copernicus.org/articles/1/701/2020/ eISSN: 2698-4016 Text 2020 ftcopernicus https://doi.org/10.5194/wcd-1-701-2020 2020-11-16T17:22:15Z Local diabatic heating and temperature anomaly fields need to be positively correlated for the diabatic heating to maintain a circulation against dissipation. Here we quantify the thermodynamic contribution of local air–sea heat exchange on the evolution of weather systems using an index of the spatial covariance between heat flux at the air–sea interface and air temperature at 850 hPa upstream of the North Atlantic storm track, corresponding with the Gulf Stream extension region. The index is found to be almost exclusively negative, indicating that the air–sea heat fluxes act locally as a sink on potential energy. It features bursts of high activity alternating with longer periods of lower activity. The characteristics of these high-index bursts are elucidated through composite analysis and the mechanisms are investigated in a phase space spanned by two different index components. It is found that the negative peaks in the index correspond with thermodynamic activity triggered by the passage of a weather system over a spatially variable sea-surface temperature field; our results indicate that most of this thermodynamically active heat exchange is realised within the cold sector of the weather systems. Text North Atlantic Copernicus Publications: E-Journals Weather and Climate Dynamics 1 2 701 713 |
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Open Polar |
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Copernicus Publications: E-Journals |
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ftcopernicus |
language |
English |
description |
Local diabatic heating and temperature anomaly fields need to be positively correlated for the diabatic heating to maintain a circulation against dissipation. Here we quantify the thermodynamic contribution of local air–sea heat exchange on the evolution of weather systems using an index of the spatial covariance between heat flux at the air–sea interface and air temperature at 850 hPa upstream of the North Atlantic storm track, corresponding with the Gulf Stream extension region. The index is found to be almost exclusively negative, indicating that the air–sea heat fluxes act locally as a sink on potential energy. It features bursts of high activity alternating with longer periods of lower activity. The characteristics of these high-index bursts are elucidated through composite analysis and the mechanisms are investigated in a phase space spanned by two different index components. It is found that the negative peaks in the index correspond with thermodynamic activity triggered by the passage of a weather system over a spatially variable sea-surface temperature field; our results indicate that most of this thermodynamically active heat exchange is realised within the cold sector of the weather systems. |
format |
Text |
author |
Marcheggiani, Andrea Ambaum, Maarten H. P. |
spellingShingle |
Marcheggiani, Andrea Ambaum, Maarten H. P. The role of heat-flux–temperature covariance in the evolution of weather systems |
author_facet |
Marcheggiani, Andrea Ambaum, Maarten H. P. |
author_sort |
Marcheggiani, Andrea |
title |
The role of heat-flux–temperature covariance in the evolution of weather systems |
title_short |
The role of heat-flux–temperature covariance in the evolution of weather systems |
title_full |
The role of heat-flux–temperature covariance in the evolution of weather systems |
title_fullStr |
The role of heat-flux–temperature covariance in the evolution of weather systems |
title_full_unstemmed |
The role of heat-flux–temperature covariance in the evolution of weather systems |
title_sort |
role of heat-flux–temperature covariance in the evolution of weather systems |
publishDate |
2020 |
url |
https://doi.org/10.5194/wcd-1-701-2020 https://wcd.copernicus.org/articles/1/701/2020/ |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
eISSN: 2698-4016 |
op_relation |
doi:10.5194/wcd-1-701-2020 https://wcd.copernicus.org/articles/1/701/2020/ |
op_doi |
https://doi.org/10.5194/wcd-1-701-2020 |
container_title |
Weather and Climate Dynamics |
container_volume |
1 |
container_issue |
2 |
container_start_page |
701 |
op_container_end_page |
713 |
_version_ |
1766131769183043584 |