Impact of Roughness Length on WRF Simulated Land‐Atmosphere Interactions Over a Hyper‐Arid Region
Abstract The aerodynamic roughness length is a crucial parameter that controls surface variables including the horizontal wind, surface temperature, and heat fluxes. Despite its importance, in the Weather Research and Forecasting (WRF) model, this parameter is typically assigned a predefined value,...
| Main Authors: | , , , , , , , , , , , , |
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| Format: | Article |
| Language: | English |
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American Geophysical Union (AGU)
2020-06-01
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| Series: | Earth and Space Science |
| Subjects: | |
| Online Access: | https://doi.org/10.1029/2020EA001165 |
| _version_ | 1811220334126301184 |
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| author | Narendra Reddy Nelli Marouane Temimi Ricardo Morais Fonseca Michael John Weston Mohana Satyanarayana Thota Vineeth Krishnan Valappil Oliver Branch Volker Wulfmeyer Youssef Wehbe Taha Al Hosary Abdeltawab Shalaby Noor Al Shamsi Hajer Al Naqbi |
| author_facet | Narendra Reddy Nelli Marouane Temimi Ricardo Morais Fonseca Michael John Weston Mohana Satyanarayana Thota Vineeth Krishnan Valappil Oliver Branch Volker Wulfmeyer Youssef Wehbe Taha Al Hosary Abdeltawab Shalaby Noor Al Shamsi Hajer Al Naqbi |
| author_sort | Narendra Reddy Nelli |
| collection | DOAJ |
| description | Abstract The aerodynamic roughness length is a crucial parameter that controls surface variables including the horizontal wind, surface temperature, and heat fluxes. Despite its importance, in the Weather Research and Forecasting (WRF) model, this parameter is typically assigned a predefined value, mostly based on the dominant land‐use type. In this work, the roughness length is first estimated from eddy‐covariance measurements at Al Ain in the United Arab Emirates (UAE), a hyper‐arid region, and then ingested into WRF. The estimated roughness length is in the range 1.3–2.2 mm, one order smaller than the default value used in WRF. In line with previous studies, and from WRF model simulations during the warm and cold seasons, it is concluded that, when the roughness length is decreased by an order of magnitude, the horizontal wind speed increases by up to 1 m s−1, the surface temperature rises by up to 2.5°C, and the sensible heat flux decreases by as much as 10 W m−2. In comparison with in situ station and eddy covariance data, and when forced with the updated roughness length, WRF gives more accurate 2‐m air temperature and sensible heat flux predictions. For prevailing wind speeds >6 m s−1, the model underestimates the strength of the near‐surface wind, a tendency that can be partially corrected, typically by 1–3 m s−1, when the updated roughness length is considered. For low wind speeds (<4 m s−1), however, WRF generally overestimates the strength of the wind. |
| first_indexed | 2024-04-12T07:40:05Z |
| format | Article |
| id | doaj.art-50ab235fc3434ec888bf7f74a612ae06 |
| institution | Directory Open Access Journal |
| issn | 2333-5084 |
| language | English |
| last_indexed | 2024-04-12T07:40:05Z |
| publishDate | 2020-06-01 |
| publisher | American Geophysical Union (AGU) |
| record_format | Article |
| series | Earth and Space Science |
| spelling | doaj.art-50ab235fc3434ec888bf7f74a612ae062022-12-22T03:41:50ZengAmerican Geophysical Union (AGU)Earth and Space Science2333-50842020-06-0176n/an/a10.1029/2020EA001165Impact of Roughness Length on WRF Simulated Land‐Atmosphere Interactions Over a Hyper‐Arid RegionNarendra Reddy Nelli0Marouane Temimi1Ricardo Morais Fonseca2Michael John Weston3Mohana Satyanarayana Thota4Vineeth Krishnan Valappil5Oliver Branch6Volker Wulfmeyer7Youssef Wehbe8Taha Al Hosary9Abdeltawab Shalaby10Noor Al Shamsi11Hajer Al Naqbi12Khalifa University of Science and Technology Abu Dhabi United Arab EmiratesKhalifa University of Science and Technology Abu Dhabi United Arab EmiratesKhalifa University of Science and Technology Abu Dhabi United Arab EmiratesKhalifa University of Science and Technology Abu Dhabi United Arab EmiratesKhalifa University of Science and Technology Abu Dhabi United Arab EmiratesKhalifa University of Science and Technology Abu Dhabi United Arab EmiratesInstitute of Physics and Meteorology University of Hohenheim Stuttgart GermanyInstitute of Physics and Meteorology University of Hohenheim Stuttgart GermanyKhalifa University of Science and Technology Abu Dhabi United Arab EmiratesNational Center of Meteorology Abu Dhabi United Arab EmiratesNational Center of Meteorology Abu Dhabi United Arab EmiratesNational Center of Meteorology Abu Dhabi United Arab EmiratesNational Center of Meteorology Abu Dhabi United Arab EmiratesAbstract The aerodynamic roughness length is a crucial parameter that controls surface variables including the horizontal wind, surface temperature, and heat fluxes. Despite its importance, in the Weather Research and Forecasting (WRF) model, this parameter is typically assigned a predefined value, mostly based on the dominant land‐use type. In this work, the roughness length is first estimated from eddy‐covariance measurements at Al Ain in the United Arab Emirates (UAE), a hyper‐arid region, and then ingested into WRF. The estimated roughness length is in the range 1.3–2.2 mm, one order smaller than the default value used in WRF. In line with previous studies, and from WRF model simulations during the warm and cold seasons, it is concluded that, when the roughness length is decreased by an order of magnitude, the horizontal wind speed increases by up to 1 m s−1, the surface temperature rises by up to 2.5°C, and the sensible heat flux decreases by as much as 10 W m−2. In comparison with in situ station and eddy covariance data, and when forced with the updated roughness length, WRF gives more accurate 2‐m air temperature and sensible heat flux predictions. For prevailing wind speeds >6 m s−1, the model underestimates the strength of the near‐surface wind, a tendency that can be partially corrected, typically by 1–3 m s−1, when the updated roughness length is considered. For low wind speeds (<4 m s−1), however, WRF generally overestimates the strength of the wind.https://doi.org/10.1029/2020EA001165Aerodynamic roughness lengthnear‐surface wind speedsensible heat fluxsurface temperatureWRF modelhyper‐arid region |
| spellingShingle | Narendra Reddy Nelli Marouane Temimi Ricardo Morais Fonseca Michael John Weston Mohana Satyanarayana Thota Vineeth Krishnan Valappil Oliver Branch Volker Wulfmeyer Youssef Wehbe Taha Al Hosary Abdeltawab Shalaby Noor Al Shamsi Hajer Al Naqbi Impact of Roughness Length on WRF Simulated Land‐Atmosphere Interactions Over a Hyper‐Arid Region Earth and Space Science Aerodynamic roughness length near‐surface wind speed sensible heat flux surface temperature WRF model hyper‐arid region |
| title | Impact of Roughness Length on WRF Simulated Land‐Atmosphere Interactions Over a Hyper‐Arid Region |
| title_full | Impact of Roughness Length on WRF Simulated Land‐Atmosphere Interactions Over a Hyper‐Arid Region |
| title_fullStr | Impact of Roughness Length on WRF Simulated Land‐Atmosphere Interactions Over a Hyper‐Arid Region |
| title_full_unstemmed | Impact of Roughness Length on WRF Simulated Land‐Atmosphere Interactions Over a Hyper‐Arid Region |
| title_short | Impact of Roughness Length on WRF Simulated Land‐Atmosphere Interactions Over a Hyper‐Arid Region |
| title_sort | impact of roughness length on wrf simulated land atmosphere interactions over a hyper arid region |
| topic | Aerodynamic roughness length near‐surface wind speed sensible heat flux surface temperature WRF model hyper‐arid region |
| url | https://doi.org/10.1029/2020EA001165 |
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