Simulation of Meteorological Fields Within and Above Urban and Rural Canopies with a Mesoscale Model

Dupont, Sylvain; Otte, Tanya L.; Ching, Jason

doi:10.1023/b:boun.0000037327.19159.ac

Cited by 168 publications

(142 citation statements)

References 41 publications

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“…Masson, 2000;Kusaka et al, 2001;Lee and Park, 2008;Oleson et al, 2008) and the multilayer schemes (e.g. Martilli et al, 2002;Dupont et al, 2004;Kondo et al, 2005). The former group of UCM usually focuses on parametrization of surface energy budgets and has been adopted in the Weather Research and Forecasting (WRF) model (Chen et al, 2011), whereas the latter group attempts to also better represent the flow dynamics induced in urban canopies, although the flow is still parametrized rather than resolved as for example in direct (Coceal et al, 2006) or large-eddy (Bou-Zeid et al, 2009) turbulence simulations.…”

Section: Introductionmentioning

confidence: 99%

A coupled energy transport and hydrological model for urban canopies evaluated using a wireless sensor network

Wang

Bou‐Zeid

Smith

2012

Quart J Royal Meteoro Soc

186

143

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We propose a new surface exchange scheme coupling the transport of energy and water in urban canopies. The new model resolves the subfacet heterogeneity of urban surfaces, which is particularly useful for capturing surface exchange processes from vegetated urban surfaces, such as lawns or green roofs. We develop detailed urban hydrological models for surfaces consisting of either natural (soil and vegetation) or engineered materials with water-holding capacity. The coupling of energy and water transport enables us to parametrize surface evaporation from different urban facets including soils, vegetation and water-holding engineered surfaces. The new coupled model is evaluated using field measurement data obtained through a wireless sensor network deployed over the Princeton University campus. Comparison of model prediction and measured results shows that the proposed surface exchange scheme is able to predict widely varying surface temperatures for each subfacet with good accuracy. Different weather conditions and seasonal variability are found to have insignificant effect on the model performance. The new model is also able to capture the subsurface hydrological processes with reasonable accuracy, particularly for urban lawns. The proposed model is then applied to assess different mitigation strategies of the urban heat island effect.Key Words: urban canopy model; urban hydrology; urban heat island; land-atmosphere interaction; water-holding pavements

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Section: Introductionmentioning

confidence: 99%

A coupled energy transport and hydrological model for urban canopies evaluated using a wireless sensor network

Wang

Bou‐Zeid

Smith

2012

Quart J Royal Meteoro Soc

186

143

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“…The existence of various surface types and different exposures to solar radiation in a complex surface geometry can lead to significant variations in heat fluxes over short distances. This problem is well-known, but for practical purposes various simplifications that assume homogeneous properties at the surface like Monin-Obukhov similarity (MOS) are still widely used to estimate the sensible heat flux in mesoscale models, typically with the scalar roughness approach [15,49]. When this method is used, one of the main difficulties is to define a representative value for the surface temperature.…”

Section: Introductionmentioning

confidence: 99%

Estimation of urban sensible heat flux using a dense wireless network of observations

et al. 2009

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The determination of the sensible heat flux over urban terrain is challenging due to irregular surface geometry and surface types. To address this, in 2006-07, a major field campaign (LUCE) took place at the École Polytechnique Fédérale de Lausanne campus, a moderately occupied urban site. A distributed network of 92 wireless weather stations was combined with routine atmospheric profiling, offering high temporal and spatial resolution meteorological measurements. The objective of this study is to estimate the sensible heat flux over the built environment under convective conditions. Calculations were based on Monin-Obukhov similarity for temperature in the surface layer. The results illustrate a good agreement between the sensible heat flux inferred from the thermal roughness length approach and independent calibrated measurements from a scintillometer located inside the urban canopy. It also shows that using only one well-selected station can provide a good estimate of the sensible heat flux over the campus for convective conditions. Overall, this

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“…However the urban effect on water vapour has been documented for a few cases but only based on surface measurements (Lee, 1991;Jáuregui and Tejeda, 1998;Unger, 1999;Deosthali, 2000;Unkaševic et al, 2001;Richards, 2005). Indeed, water vapour monitoring is complicated due to the specific constraints of urban areas: soundings are seldom released in city centres, the natural high variability of water vapour is enhanced by the heterogeneities of the urban surface properties which affect the representativeness of surface measurements of urban water vapour and impact on numerical modelling which requires specific subgrid-scale parametrization (Masson, 2000(Masson, , 2006Dupont et al, 2004Dupont et al, , 2006. Overall, studies found in the literature (all previous references in this paragraph) agree WATER VAPOUR VARIABILITY IN AN URBAN AREA 1267 that urban areas are drier (both in specific and relative humidity) than surrounding rural areas due to the lack of urban sources.…”

Section: Introductionmentioning

confidence: 99%

Water vapour variability induced by urban/rural surface heterogeneities during convective conditions

Champollion

Drobinski

Haeffelin

et al. 2009

Quart J Royal Meteoro Soc

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Scientific interest in urban meteorology has increased because highly populated areas experience high vulnerability to pollution or heavy rain. However, compared to urban air quality or urban heat island (UHI) processes, the urban water vapour cycle is poorly understood because it has been investigated less due to the lack of upper-air measurements and the high sensitivity of surface measurements to local heterogeneities. In this paper, surface measurements of wind, temperature, pressure and humidity, as well as integrated water vapour (IWV) from GPS and MODIS and numerical simulations, have been used to investigate the urban cycle of water vapour in May and June 2004 during the VAPIC field experiment in the Paris area.The surface data show the typical characteristics of an urban area with the absence of water vapour sources and a UHI of about 6 • C at night. The urban IWV distribution differs completely, with an urban IWV excess on average between 1600 and 0600 UTC (with a maximum of about 1.5 kg m −2 at 0600 and 1700 UTC). No IWV difference between the urban and rural areas is found in the middle of the day. The numerical simulations reproduce accurately the urban IWV anomaly.Shallow surface wind convergence associated with the UHI during nighttime provides moisture from the rural areas. Urban areas are therefore under wind convergence for most of the time. The rural water vapour sources and the depth of the convergence control the amplitude of the urban IWV excess. At about 1200 UTC, entrainment at the top of the urban boundary layer is the key process that inhibits the urban IWV excess observed at night.

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Simulation of Meteorological Fields Within and Above Urban and Rural Canopies with a Mesoscale Model

Cited by 168 publications

References 41 publications

A coupled energy transport and hydrological model for urban canopies evaluated using a wireless sensor network

A coupled energy transport and hydrological model for urban canopies evaluated using a wireless sensor network

Estimation of urban sensible heat flux using a dense wireless network of observations

Water vapour variability induced by urban/rural surface heterogeneities during convective conditions

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