A modified vertical eddy diffusivity parameterization in the HWRF model based on large eddy simulations and its impact on the prediction of two landfalling hurricanes
Vertical eddy diffusivity (VED) in the planetary boundary layer (PBL) has a significant impact on forecasts of tropical cyclone (TC) structure and intensity. VED uncertainties in PBL parameterizations can be partly attributed to the model’s inability to represent roll vortices (RV). In this study, R...
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| Format: | Article |
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Frontiers Media S.A.
2023-11-01
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| Series: | Frontiers in Earth Science |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/feart.2023.1320192/full |
| _version_ | 1797447693850640384 |
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| author | Xin Li Zhaoxia Pu Jun A. Zhang Jun A. Zhang Zhan Zhang |
| author_facet | Xin Li Zhaoxia Pu Jun A. Zhang Jun A. Zhang Zhan Zhang |
| author_sort | Xin Li |
| collection | DOAJ |
| description | Vertical eddy diffusivity (VED) in the planetary boundary layer (PBL) has a significant impact on forecasts of tropical cyclone (TC) structure and intensity. VED uncertainties in PBL parameterizations can be partly attributed to the model’s inability to represent roll vortices (RV). In this study, RV effects on turbulent fluxes derived from a large eddy simulation (LES) by Li et al. (Geophys. Res. Lett., 2021, 48, e2020GL090703) are added to the VED parameterization of the PBL scheme within the operational Hurricane Weather Research and Forecasting (HWRF) model. RV contribution to VED is parameterized through a coefficient and varies with the RV intensity and velocity scale. A modification over land has also been implemented. This modified VED parameterization is compared with the original wind-speed-dependent VED scheme in HWRF. Retrospective HWRF forecasts of Hurricanes Florence (2018) and Laura (2020) are analyzed to evaluate the impacts of the modified VED scheme on landfalling hurricane forecasts. Results show that the modified PBL scheme with the RV effect leads to an improvement in 10-m maximum wind speed forecasts of 14%–31%, with a neutral to positive improvement for track forecasts. Improved wind structure and precipitation forecasts against observations are also noted with the modified PBL scheme. Further diagnoses indicate that the revised PBL scheme enhances moist entropy in the boundary layer over land, leading to improved TC intensity prediction compared to the original scheme. |
| first_indexed | 2024-03-09T13:59:37Z |
| format | Article |
| id | doaj.art-10d6ed6b4f1c481d898343596052dc15 |
| institution | Directory Open Access Journal |
| issn | 2296-6463 |
| language | English |
| last_indexed | 2024-03-09T13:59:37Z |
| publishDate | 2023-11-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Earth Science |
| spelling | doaj.art-10d6ed6b4f1c481d898343596052dc152023-11-30T08:36:11ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632023-11-011110.3389/feart.2023.13201921320192A modified vertical eddy diffusivity parameterization in the HWRF model based on large eddy simulations and its impact on the prediction of two landfalling hurricanesXin Li0Zhaoxia Pu1Jun A. Zhang2Jun A. Zhang3Zhan Zhang4Department of Atmospheric Sciences, University of Utah, Salt Lake City, UT, United StatesDepartment of Atmospheric Sciences, University of Utah, Salt Lake City, UT, United StatesCooperative Institute for Marine and Atmospheric Studies, University of Miami, Miami, FL, United StatesHurricane Research Division, NOAA/AOML, Miami, FL, United StatesEnvironmental Modeling Center, NCEP/NOAA, College Park, MD, United StatesVertical eddy diffusivity (VED) in the planetary boundary layer (PBL) has a significant impact on forecasts of tropical cyclone (TC) structure and intensity. VED uncertainties in PBL parameterizations can be partly attributed to the model’s inability to represent roll vortices (RV). In this study, RV effects on turbulent fluxes derived from a large eddy simulation (LES) by Li et al. (Geophys. Res. Lett., 2021, 48, e2020GL090703) are added to the VED parameterization of the PBL scheme within the operational Hurricane Weather Research and Forecasting (HWRF) model. RV contribution to VED is parameterized through a coefficient and varies with the RV intensity and velocity scale. A modification over land has also been implemented. This modified VED parameterization is compared with the original wind-speed-dependent VED scheme in HWRF. Retrospective HWRF forecasts of Hurricanes Florence (2018) and Laura (2020) are analyzed to evaluate the impacts of the modified VED scheme on landfalling hurricane forecasts. Results show that the modified PBL scheme with the RV effect leads to an improvement in 10-m maximum wind speed forecasts of 14%–31%, with a neutral to positive improvement for track forecasts. Improved wind structure and precipitation forecasts against observations are also noted with the modified PBL scheme. Further diagnoses indicate that the revised PBL scheme enhances moist entropy in the boundary layer over land, leading to improved TC intensity prediction compared to the original scheme.https://www.frontiersin.org/articles/10.3389/feart.2023.1320192/fullplanetary boundary layerhurricaneslandfallparameterizationroll vorticesnumerical prediction |
| spellingShingle | Xin Li Zhaoxia Pu Jun A. Zhang Jun A. Zhang Zhan Zhang A modified vertical eddy diffusivity parameterization in the HWRF model based on large eddy simulations and its impact on the prediction of two landfalling hurricanes Frontiers in Earth Science planetary boundary layer hurricanes landfall parameterization roll vortices numerical prediction |
| title | A modified vertical eddy diffusivity parameterization in the HWRF model based on large eddy simulations and its impact on the prediction of two landfalling hurricanes |
| title_full | A modified vertical eddy diffusivity parameterization in the HWRF model based on large eddy simulations and its impact on the prediction of two landfalling hurricanes |
| title_fullStr | A modified vertical eddy diffusivity parameterization in the HWRF model based on large eddy simulations and its impact on the prediction of two landfalling hurricanes |
| title_full_unstemmed | A modified vertical eddy diffusivity parameterization in the HWRF model based on large eddy simulations and its impact on the prediction of two landfalling hurricanes |
| title_short | A modified vertical eddy diffusivity parameterization in the HWRF model based on large eddy simulations and its impact on the prediction of two landfalling hurricanes |
| title_sort | modified vertical eddy diffusivity parameterization in the hwrf model based on large eddy simulations and its impact on the prediction of two landfalling hurricanes |
| topic | planetary boundary layer hurricanes landfall parameterization roll vortices numerical prediction |
| url | https://www.frontiersin.org/articles/10.3389/feart.2023.1320192/full |
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