Study of Urban Heat Islands Using Different Urban Canopy Models and Identification Methods
This work aims to compare the performance of the single‑(SLUCM) and multilayer (BEP-Building effect parameterization) urban canopy models (UCMs) coupled with the Weather Research and Forecasting model (WRF), along with the application of two urban heat island (UHI) identification methods. The identi...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-04-01
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| Series: | Atmosphere |
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| Online Access: | https://www.mdpi.com/2073-4433/12/4/521 |
| _version_ | 1797537111537090560 |
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| author | Rui Silva Ana Cristina Carvalho David Carvalho Alfredo Rocha |
| author_facet | Rui Silva Ana Cristina Carvalho David Carvalho Alfredo Rocha |
| author_sort | Rui Silva |
| collection | DOAJ |
| description | This work aims to compare the performance of the single‑(SLUCM) and multilayer (BEP-Building effect parameterization) urban canopy models (UCMs) coupled with the Weather Research and Forecasting model (WRF), along with the application of two urban heat island (UHI) identification methods. The identification methods are: (1) the “classic method”, based on the temperature difference between urban and rural areas; (2) the “local method” based on the temperature difference at each urban location when the model land use is considered urban, and when it is replaced by the dominant rural land use category of the urban surroundings. The study is performed as a case study for the city of Lisbon, Portugal, during the record-breaking August 2003 heatwave event. Two main differences were found in the UHI intensity (UHII) and spatial distribution between the identification methods: a reduction by half in the UHII during nighttime when using the local method; and a dipole signal in the daytime and nighttime UHI spatial pattern when using the classic method, associated with the sheltering effect provided by the high topography in the northern part of the city, that reduces the advective cooling in the lower areas under prevalent northern wind conditions. These results highlight the importance of using the local method in UHI modeling studies to fully isolate urban canopy and regional geographic contributions to the UHII and distribution. Considerable improvements were obtained in the near‑surface temperature representation by coupling WRF with the UCMs but better with SLUCM. The nighttime UHII over the most densely urbanized areas is lower in BEP, which can be linked to its larger nocturnal turbulent kinetic energy (TKE) near the surface and negative sensible heat (SH) fluxes. The latter may be associated with the lower surface skin temperature found in BEP, possibly owing to larger turbulent SH fluxes near the surface. Due to its higher urban TKE, BEP significantly overestimates the planetary boundary layer height compared with SLUCM and observations from soundings. The comparison with a previous study for the city of Lisbon shows that BEP model simulation results heavily rely on the number and distribution of vertical levels within the urban canopy. |
| first_indexed | 2024-03-10T12:10:26Z |
| format | Article |
| id | doaj.art-4003837d546e486c8efe70008e4d9d94 |
| institution | Directory Open Access Journal |
| issn | 2073-4433 |
| language | English |
| last_indexed | 2024-03-10T12:10:26Z |
| publishDate | 2021-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Atmosphere |
| spelling | doaj.art-4003837d546e486c8efe70008e4d9d942023-11-21T16:15:47ZengMDPI AGAtmosphere2073-44332021-04-0112452110.3390/atmos12040521Study of Urban Heat Islands Using Different Urban Canopy Models and Identification MethodsRui Silva0Ana Cristina Carvalho1David Carvalho2Alfredo Rocha3Department of Physics and Centre for Environmental and Marine Studies (CESAM), Campus Universitário de Santiago, University of Aveiro, 3810-093 Aveiro, PortugalSwedish Meteorological and Hydrological Institute, SMHI FoUl, 601 76 Norrköping, SwedenDepartment of Physics and Centre for Environmental and Marine Studies (CESAM), Campus Universitário de Santiago, University of Aveiro, 3810-093 Aveiro, PortugalDepartment of Physics and Centre for Environmental and Marine Studies (CESAM), Campus Universitário de Santiago, University of Aveiro, 3810-093 Aveiro, PortugalThis work aims to compare the performance of the single‑(SLUCM) and multilayer (BEP-Building effect parameterization) urban canopy models (UCMs) coupled with the Weather Research and Forecasting model (WRF), along with the application of two urban heat island (UHI) identification methods. The identification methods are: (1) the “classic method”, based on the temperature difference between urban and rural areas; (2) the “local method” based on the temperature difference at each urban location when the model land use is considered urban, and when it is replaced by the dominant rural land use category of the urban surroundings. The study is performed as a case study for the city of Lisbon, Portugal, during the record-breaking August 2003 heatwave event. Two main differences were found in the UHI intensity (UHII) and spatial distribution between the identification methods: a reduction by half in the UHII during nighttime when using the local method; and a dipole signal in the daytime and nighttime UHI spatial pattern when using the classic method, associated with the sheltering effect provided by the high topography in the northern part of the city, that reduces the advective cooling in the lower areas under prevalent northern wind conditions. These results highlight the importance of using the local method in UHI modeling studies to fully isolate urban canopy and regional geographic contributions to the UHII and distribution. Considerable improvements were obtained in the near‑surface temperature representation by coupling WRF with the UCMs but better with SLUCM. The nighttime UHII over the most densely urbanized areas is lower in BEP, which can be linked to its larger nocturnal turbulent kinetic energy (TKE) near the surface and negative sensible heat (SH) fluxes. The latter may be associated with the lower surface skin temperature found in BEP, possibly owing to larger turbulent SH fluxes near the surface. Due to its higher urban TKE, BEP significantly overestimates the planetary boundary layer height compared with SLUCM and observations from soundings. The comparison with a previous study for the city of Lisbon shows that BEP model simulation results heavily rely on the number and distribution of vertical levels within the urban canopy.https://www.mdpi.com/2073-4433/12/4/521urban heat islandWRF modelurban canopy modelturbulent kinetic energyheatwaveLisbon |
| spellingShingle | Rui Silva Ana Cristina Carvalho David Carvalho Alfredo Rocha Study of Urban Heat Islands Using Different Urban Canopy Models and Identification Methods Atmosphere urban heat island WRF model urban canopy model turbulent kinetic energy heatwave Lisbon |
| title | Study of Urban Heat Islands Using Different Urban Canopy Models and Identification Methods |
| title_full | Study of Urban Heat Islands Using Different Urban Canopy Models and Identification Methods |
| title_fullStr | Study of Urban Heat Islands Using Different Urban Canopy Models and Identification Methods |
| title_full_unstemmed | Study of Urban Heat Islands Using Different Urban Canopy Models and Identification Methods |
| title_short | Study of Urban Heat Islands Using Different Urban Canopy Models and Identification Methods |
| title_sort | study of urban heat islands using different urban canopy models and identification methods |
| topic | urban heat island WRF model urban canopy model turbulent kinetic energy heatwave Lisbon |
| url | https://www.mdpi.com/2073-4433/12/4/521 |
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