Application of the Cyclone Phase Space to Extratropical Transition in a Global Climate Model
Abstract The authors analyze the global statistics of tropical cyclones undergoing extratropical transition (ET) in the Forecast‐oriented Low Ocean Resolution version of CM2.5 with Flux Adjustment (FLOR‐FA). The cyclone phase space (CPS) is used to diagnose ET. A simulation of the recent historical...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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American Geophysical Union (AGU)
2020-04-01
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| Series: | Journal of Advances in Modeling Earth Systems |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2019MS001878 |
| _version_ | 1797662360669782016 |
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| author | Melanie Bieli Adam H. Sobel Suzana J. Camargo Hiroyuki Murakami Gabriel A. Vecchi |
| author_facet | Melanie Bieli Adam H. Sobel Suzana J. Camargo Hiroyuki Murakami Gabriel A. Vecchi |
| author_sort | Melanie Bieli |
| collection | DOAJ |
| description | Abstract The authors analyze the global statistics of tropical cyclones undergoing extratropical transition (ET) in the Forecast‐oriented Low Ocean Resolution version of CM2.5 with Flux Adjustment (FLOR‐FA). The cyclone phase space (CPS) is used to diagnose ET. A simulation of the recent historical climate is analyzed and compared with data from the Japanese 55‐year Reanalysis (JRA‐55), and then a simulation of late 21st century climate under Representative Concentration Pathway 4.5 is compared to the historical simulation. When CPS is applied to the FLOR‐FA output in the historical simulation, the results diverge from those obtained from JRA‐55 by having an unrealistic number of ET cases at low latitudes, due to the presence of strong local maxima in the upper‐level geopotential. These features mislead CPS into detecting a cold core where one is not present. The misdiagnosis is largely corrected by replacing the maxima required by CPS with the 95th percentile values, smoothing the CPS trajectories in time, or both. Other climate models may contain grid‐scale structures akin to those in FLOR‐FA and, when used for CPS analysis, require solutions such as those discussed here. Comparisons of ET in the projected future climate with the historical climate show a number of changes that are robust to the details of the ET diagnosis, though few are statistically significant according to standard tests. Among them are an increase in the ET fraction and a reduction in the mean latitude at which ET occurs in the western North Pacific. |
| first_indexed | 2024-03-11T18:58:04Z |
| format | Article |
| id | doaj.art-fd938cb4d6024fce8590cb724057736b |
| institution | Directory Open Access Journal |
| issn | 1942-2466 |
| language | English |
| last_indexed | 2024-03-11T18:58:04Z |
| publishDate | 2020-04-01 |
| publisher | American Geophysical Union (AGU) |
| record_format | Article |
| series | Journal of Advances in Modeling Earth Systems |
| spelling | doaj.art-fd938cb4d6024fce8590cb724057736b2023-10-10T14:11:54ZengAmerican Geophysical Union (AGU)Journal of Advances in Modeling Earth Systems1942-24662020-04-01124n/an/a10.1029/2019MS001878Application of the Cyclone Phase Space to Extratropical Transition in a Global Climate ModelMelanie Bieli0Adam H. Sobel1Suzana J. Camargo2Hiroyuki Murakami3Gabriel A. Vecchi4Department of Applied Physics and Applied Mathematics Columbia University New York NY USADepartment of Applied Physics and Applied Mathematics Columbia University New York NY USALamont‐Doherty Earth Observatory Columbia University Palisades NY USAGeophysical Fluid Dynamics Laboratory National Oceanic and Atmospheric Administration Princeton NJ USADepartment of Geosciences Princeton University Princeton NJ USAAbstract The authors analyze the global statistics of tropical cyclones undergoing extratropical transition (ET) in the Forecast‐oriented Low Ocean Resolution version of CM2.5 with Flux Adjustment (FLOR‐FA). The cyclone phase space (CPS) is used to diagnose ET. A simulation of the recent historical climate is analyzed and compared with data from the Japanese 55‐year Reanalysis (JRA‐55), and then a simulation of late 21st century climate under Representative Concentration Pathway 4.5 is compared to the historical simulation. When CPS is applied to the FLOR‐FA output in the historical simulation, the results diverge from those obtained from JRA‐55 by having an unrealistic number of ET cases at low latitudes, due to the presence of strong local maxima in the upper‐level geopotential. These features mislead CPS into detecting a cold core where one is not present. The misdiagnosis is largely corrected by replacing the maxima required by CPS with the 95th percentile values, smoothing the CPS trajectories in time, or both. Other climate models may contain grid‐scale structures akin to those in FLOR‐FA and, when used for CPS analysis, require solutions such as those discussed here. Comparisons of ET in the projected future climate with the historical climate show a number of changes that are robust to the details of the ET diagnosis, though few are statistically significant according to standard tests. Among them are an increase in the ET fraction and a reduction in the mean latitude at which ET occurs in the western North Pacific.https://doi.org/10.1029/2019MS001878cyclone phase spaceclimate modelextratropical transitiontropical cyclones |
| spellingShingle | Melanie Bieli Adam H. Sobel Suzana J. Camargo Hiroyuki Murakami Gabriel A. Vecchi Application of the Cyclone Phase Space to Extratropical Transition in a Global Climate Model Journal of Advances in Modeling Earth Systems cyclone phase space climate model extratropical transition tropical cyclones |
| title | Application of the Cyclone Phase Space to Extratropical Transition in a Global Climate Model |
| title_full | Application of the Cyclone Phase Space to Extratropical Transition in a Global Climate Model |
| title_fullStr | Application of the Cyclone Phase Space to Extratropical Transition in a Global Climate Model |
| title_full_unstemmed | Application of the Cyclone Phase Space to Extratropical Transition in a Global Climate Model |
| title_short | Application of the Cyclone Phase Space to Extratropical Transition in a Global Climate Model |
| title_sort | application of the cyclone phase space to extratropical transition in a global climate model |
| topic | cyclone phase space climate model extratropical transition tropical cyclones |
| url | https://doi.org/10.1029/2019MS001878 |
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