A Weak Temperature Gradient Framework to Quantify the Causes of Potential Intensity Variability in the Tropics
<jats:title>Abstract</jats:title><jats:p>Potential intensity (PI) has been shown to have a linear sensitivity to sea surface temperature (SST) of about 8 m s<jats:sup>−1</jats:sup> K<jats:sup>−1</jats:sup>, which is close to the sensitivity of PI in simulati...
Main Authors: | , |
---|---|
Other Authors: | |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
American Meteorological Society
2023
|
Subjects: | |
Online Access: | https://hdl.handle.net/1721.1/147976 |
id |
ftmit:oai:dspace.mit.edu:1721.1/147976 |
---|---|
record_format |
openpolar |
spelling |
ftmit:oai:dspace.mit.edu:1721.1/147976 2023-06-11T04:14:54+02:00 A Weak Temperature Gradient Framework to Quantify the Causes of Potential Intensity Variability in the Tropics Rousseau-Rizzi, Raphaël Emanuel, Kerry Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences 2023-02-08T17:19:40Z application/pdf https://hdl.handle.net/1721.1/147976 en eng American Meteorological Society 10.1175/JCLI-D-21-0139.1 Journal of Climate https://hdl.handle.net/1721.1/147976 Rousseau-Rizzi, Raphaël and Emanuel, Kerry. 2021. "A Weak Temperature Gradient Framework to Quantify the Causes of Potential Intensity Variability in the Tropics." Journal of Climate, 34 (21). Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. American Meteorological Society (AMS) Article http://purl.org/eprint/type/JournalArticle 2023 ftmit 2023-05-29T08:32:10Z <jats:title>Abstract</jats:title><jats:p>Potential intensity (PI) has been shown to have a linear sensitivity to sea surface temperature (SST) of about 8 m s<jats:sup>−1</jats:sup> K<jats:sup>−1</jats:sup>, which is close to the sensitivity of PI in simulations subject to a weak temperature gradient (WTG) approximation. This suggests that most of the PI variance is associated with local rather than global SST variations. We verify that PI perturbations are approximately linear in SST, with slopes of 1.8 ± 0.2 m s<jats:sup>−1</jats:sup> K<jats:sup>−1</jats:sup> in radiative–convective equilibrium (RCE) and 9.1 ± 0.9 m s<jats:sup>−1</jats:sup> K<jats:sup>−1</jats:sup> in WTG. To do so, we simulate the sensitivity of both RCE and WTG states in a single-column model (SCM) perturbed by changing in turn CO<jats:sub>2</jats:sub> concentration, aerosol concentrations, prescribed SST, and surface winds speeds. While PI is much more sensitive to SST in WTG than in RCE simulations, the SST itself is much less sensitive to radiative forcing in WTG than in RCE because of the absence of strong atmospheric response. Using these results, we develop a linear model, based on SST and midlevel saturation MSE perturbations, to partition SST and PI perturbations between local components occurring under a WTG constraint and global components that are representative of an RCE state. This model explains up to 95% of the variability of PI in reanalysis. The SCM-derived linear model coefficients are statistically indistinguishable from coefficients from a linear fit of reanalysis PI to SST and midlevel saturation MSE in most ocean basins. Our model shows that North Atlantic PI variations are explained almost entirely by local forcings in recent decades.</jats:p> Article in Journal/Newspaper North Atlantic DSpace@MIT (Massachusetts Institute of Technology) |
institution |
Open Polar |
collection |
DSpace@MIT (Massachusetts Institute of Technology) |
op_collection_id |
ftmit |
language |
English |
description |
<jats:title>Abstract</jats:title><jats:p>Potential intensity (PI) has been shown to have a linear sensitivity to sea surface temperature (SST) of about 8 m s<jats:sup>−1</jats:sup> K<jats:sup>−1</jats:sup>, which is close to the sensitivity of PI in simulations subject to a weak temperature gradient (WTG) approximation. This suggests that most of the PI variance is associated with local rather than global SST variations. We verify that PI perturbations are approximately linear in SST, with slopes of 1.8 ± 0.2 m s<jats:sup>−1</jats:sup> K<jats:sup>−1</jats:sup> in radiative–convective equilibrium (RCE) and 9.1 ± 0.9 m s<jats:sup>−1</jats:sup> K<jats:sup>−1</jats:sup> in WTG. To do so, we simulate the sensitivity of both RCE and WTG states in a single-column model (SCM) perturbed by changing in turn CO<jats:sub>2</jats:sub> concentration, aerosol concentrations, prescribed SST, and surface winds speeds. While PI is much more sensitive to SST in WTG than in RCE simulations, the SST itself is much less sensitive to radiative forcing in WTG than in RCE because of the absence of strong atmospheric response. Using these results, we develop a linear model, based on SST and midlevel saturation MSE perturbations, to partition SST and PI perturbations between local components occurring under a WTG constraint and global components that are representative of an RCE state. This model explains up to 95% of the variability of PI in reanalysis. The SCM-derived linear model coefficients are statistically indistinguishable from coefficients from a linear fit of reanalysis PI to SST and midlevel saturation MSE in most ocean basins. Our model shows that North Atlantic PI variations are explained almost entirely by local forcings in recent decades.</jats:p> |
author2 |
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
format |
Article in Journal/Newspaper |
author |
Rousseau-Rizzi, Raphaël Emanuel, Kerry |
spellingShingle |
Rousseau-Rizzi, Raphaël Emanuel, Kerry A Weak Temperature Gradient Framework to Quantify the Causes of Potential Intensity Variability in the Tropics |
author_facet |
Rousseau-Rizzi, Raphaël Emanuel, Kerry |
author_sort |
Rousseau-Rizzi, Raphaël |
title |
A Weak Temperature Gradient Framework to Quantify the Causes of Potential Intensity Variability in the Tropics |
title_short |
A Weak Temperature Gradient Framework to Quantify the Causes of Potential Intensity Variability in the Tropics |
title_full |
A Weak Temperature Gradient Framework to Quantify the Causes of Potential Intensity Variability in the Tropics |
title_fullStr |
A Weak Temperature Gradient Framework to Quantify the Causes of Potential Intensity Variability in the Tropics |
title_full_unstemmed |
A Weak Temperature Gradient Framework to Quantify the Causes of Potential Intensity Variability in the Tropics |
title_sort |
weak temperature gradient framework to quantify the causes of potential intensity variability in the tropics |
publisher |
American Meteorological Society |
publishDate |
2023 |
url |
https://hdl.handle.net/1721.1/147976 |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_source |
American Meteorological Society (AMS) |
op_relation |
10.1175/JCLI-D-21-0139.1 Journal of Climate https://hdl.handle.net/1721.1/147976 Rousseau-Rizzi, Raphaël and Emanuel, Kerry. 2021. "A Weak Temperature Gradient Framework to Quantify the Causes of Potential Intensity Variability in the Tropics." Journal of Climate, 34 (21). |
op_rights |
Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. |
_version_ |
1768371287890067456 |