Evaluation of the assumptions in the steady-state tropical cyclone self-stratified outflow using three-dimensional convection-allowing simulations
The criteria and assumptions that were used to derive the steady-state tropical cyclone intensity and structure theory of Emanuel and Rotunno are assessed using three-dimensional convection-allowing simulations using the Weather Research and Forecasting Model. One real-data case of Hurricane Patrici...
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| Format: | Article |
| Language: | English |
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American Meteorological Society
2020
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| Online Access: | https://hdl.handle.net/1721.1/124747 |
| _version_ | 1826194254663254016 |
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| author | Emanuel, Kerry Andrew |
| author2 | Massachusetts Institute of Technology. Program in Atmospheres, Oceans, and Climate |
| author_facet | Massachusetts Institute of Technology. Program in Atmospheres, Oceans, and Climate Emanuel, Kerry Andrew |
| author_sort | Emanuel, Kerry Andrew |
| collection | MIT |
| description | The criteria and assumptions that were used to derive the steady-state tropical cyclone intensity and structure theory of Emanuel and Rotunno are assessed using three-dimensional convection-allowing simulations using the Weather Research and Forecasting Model. One real-data case of Hurricane Patricia (2015) and two idealized simulations with and without vertical wind shear are examined. In all three simulations, the gradient wind balance is valid in the inner-core region above the boundary layer. The angular momentum M and saturation entropy surfaces s* near the top of the boundary layer, in the outflow region and along the angular momentum surface that passes the low-level radius of maximum wind MRMW are nearly congruent, satisfying the criterion of slantwise moist neutrality in the vicinity of MRMW. The theoretically derived maximum wind magnitude above the boundary layer compares well with the simulated maximum tangential wind and gradient wind using the azimuthally averaged pressure field during the intensification and quasi-steady state of the simulated storms. The Richardson number analysis of the simulated storms shows that small Richardson number (0, Ri #1) exists in the outflow region, related to both large local shear and small static stability. This criticality of the Richardson number indicates the existence of small-scale turbulence in the outflow region. We also show that the stratification of temperature along the M surfaces at the outflow region for steady-state hurricanes is approximately applicable in these three-dimensional simulations, while the radial distribution of gradient wind is qualitatively comparable to the theoretical radial profiles. Some caveats regarding the theory are also discussed. ©2019 |
| first_indexed | 2024-09-23T09:52:58Z |
| format | Article |
| id | mit-1721.1/124747 |
| institution | Massachusetts Institute of Technology |
| language | English |
| last_indexed | 2024-09-23T09:52:58Z |
| publishDate | 2020 |
| publisher | American Meteorological Society |
| record_format | dspace |
| spelling | mit-1721.1/1247472022-09-30T17:27:46Z Evaluation of the assumptions in the steady-state tropical cyclone self-stratified outflow using three-dimensional convection-allowing simulations Emanuel, Kerry Andrew Massachusetts Institute of Technology. Program in Atmospheres, Oceans, and Climate The criteria and assumptions that were used to derive the steady-state tropical cyclone intensity and structure theory of Emanuel and Rotunno are assessed using three-dimensional convection-allowing simulations using the Weather Research and Forecasting Model. One real-data case of Hurricane Patricia (2015) and two idealized simulations with and without vertical wind shear are examined. In all three simulations, the gradient wind balance is valid in the inner-core region above the boundary layer. The angular momentum M and saturation entropy surfaces s* near the top of the boundary layer, in the outflow region and along the angular momentum surface that passes the low-level radius of maximum wind MRMW are nearly congruent, satisfying the criterion of slantwise moist neutrality in the vicinity of MRMW. The theoretically derived maximum wind magnitude above the boundary layer compares well with the simulated maximum tangential wind and gradient wind using the azimuthally averaged pressure field during the intensification and quasi-steady state of the simulated storms. The Richardson number analysis of the simulated storms shows that small Richardson number (0, Ri #1) exists in the outflow region, related to both large local shear and small static stability. This criticality of the Richardson number indicates the existence of small-scale turbulence in the outflow region. We also show that the stratification of temperature along the M surfaces at the outflow region for steady-state hurricanes is approximately applicable in these three-dimensional simulations, while the radial distribution of gradient wind is qualitatively comparable to the theoretical radial profiles. Some caveats regarding the theory are also discussed. ©2019 ONR (grant no. N00014-18-1-2458) 2020-04-17T21:10:09Z 2020-04-17T21:10:09Z 2019-09 2019-02 2020-04-09T13:50:43Z Article http://purl.org/eprint/type/JournalArticle 0022-4928 1520-0469 https://hdl.handle.net/1721.1/124747 Tao, Dandan, et al., "Evaluation of the assumptions in the steady-state tropical cyclone self-stratified outflow using three-dimensional convection-allowing simulations." Journal of the atmospheric sciences 76, 9 (September 2019): p. 2995-3009 doi 10.1175/JAS-D-19-0033.1 ©2019 Author(s) en 10.1175/JAS-D-19-0033.1 Journal of the atmospheric sciences 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. application/pdf American Meteorological Society American Meteorological Society |
| spellingShingle | Emanuel, Kerry Andrew Evaluation of the assumptions in the steady-state tropical cyclone self-stratified outflow using three-dimensional convection-allowing simulations |
| title | Evaluation of the assumptions in the steady-state tropical cyclone self-stratified outflow using three-dimensional convection-allowing simulations |
| title_full | Evaluation of the assumptions in the steady-state tropical cyclone self-stratified outflow using three-dimensional convection-allowing simulations |
| title_fullStr | Evaluation of the assumptions in the steady-state tropical cyclone self-stratified outflow using three-dimensional convection-allowing simulations |
| title_full_unstemmed | Evaluation of the assumptions in the steady-state tropical cyclone self-stratified outflow using three-dimensional convection-allowing simulations |
| title_short | Evaluation of the assumptions in the steady-state tropical cyclone self-stratified outflow using three-dimensional convection-allowing simulations |
| title_sort | evaluation of the assumptions in the steady state tropical cyclone self stratified outflow using three dimensional convection allowing simulations |
| url | https://hdl.handle.net/1721.1/124747 |
| work_keys_str_mv | AT emanuelkerryandrew evaluationoftheassumptionsinthesteadystatetropicalcycloneselfstratifiedoutflowusingthreedimensionalconvectionallowingsimulations |