Modeling the Surface Energy Budget during the Thawing Period of the 2006 Montreal Urban Snow Experiment

Leroyer, Sylvie; Mailhot, Jocelyn; Bélair, Stéphane; Lemonsu, Aude; Strachan, Ian B.

doi:10.1175/2009jamc2153.1

Cited by 25 publications

(24 citation statements)

References 54 publications

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“…Similar amounts of snow fell in D.C.‐Balt prior to all flight days, including days when an urban H 2 O v excess signal was not observed (Table S1). While our measurements do not allow us to comment on the conditions impacting urban evaporation rates, other studies have shown that wintertime urban latent heat fluxes are sensitive to the physical state and availability of water on and within impervious and natural land cover [ Offerle et al ., ; Lemonsu et al ., ; Leroyer et al ., ; Bergeron and Strachan , ].…”

Section: Resultsmentioning

confidence: 99%

Urban emissions of water vapor in winter

et al. 2017

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Elevated water vapor (H2Ov) mole fractions were occasionally observed downwind of Indianapolis, IN, and the Washington, D.C.‐Baltimore, MD, area during airborne mass balance experiments conducted during winter months between 2012 and 2015. On days when an urban H2Ov excess signal was observed, H2Ov emission estimates range between 1.6 × 104 and 1.7 × 105 kg s−1 and account for up to 8.4% of the total (background + urban excess) advected flow of atmospheric boundary layer H2Ov from the urban study sites. Estimates of H2Ov emissions from combustion sources and electricity generation facility cooling towers are 1–2 orders of magnitude smaller than the urban H2Ov emission rates estimated from observations. Instances of urban H2Ov enhancement could be a result of differences in snowmelt and evaporation rates within the urban area, due in part to larger wintertime anthropogenic heat flux and land cover differences, relative to surrounding rural areas. More study is needed to understand why the urban H2Ov excess signal is observed on some days, and not others. Radiative transfer modeling indicates that the observed urban enhancements in H2Ov and other greenhouse gas mole fractions contribute only 0.1°C d−1 to the urban heat island at the surface. This integrated warming through the boundary layer is offset by longwave cooling by H2Ov at the top of the boundary layer. While the radiative impacts of urban H2Ov emissions do not meaningfully influence urban heat island intensity, urban H2Ov emissions may have the potential to alter downwind aerosol and cloud properties.

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Section: Resultsmentioning

confidence: 99%

Urban emissions of water vapor in winter

et al. 2017

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“…TEB has been intensively validated against in situ measurements, for various types of cities and urbanization, under various climates: from wintertime Montreal Leroyer et al, 2010) to Ouagadougou in the African Sahel (Offerle et al, 2005a). The other sites where TEB has been validated are old city centres, Marseilles, Toulouse, Basel, Lodz, Mexico City Lemonsu et al, 2004;Offerle et al, 2005b;Pigeon et al, 2008;Hamdi and Masson, 2008), light-industry sites , and suburban areas of Oklahoma city (Lemonsu et al, 2009), Melbourne and Nantes (Grimmond et al, 2010Lemonsu et al, 2007).…”

Section: Tebmentioning

confidence: 99%

The SURFEXv7.2 land and ocean surface platform for coupled or offline simulation of earth surface variables and fluxes

et al. 2013

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Abstract. SURFEX is a new externalized land and ocean surface platform that describes the surface fluxes and the evolution of four types of surfaces: nature, town, inland water and ocean. It is mostly based on pre-existing, well-validated scientific models that are continuously improved. The motivation for the building of SURFEX is to use strictly identical scientific models in a high range of applications in order to mutualise the research and development efforts. SURFEX can be run in offline mode (0-D or 2-D runs) or in coupled mode (from mesoscale models to numerical weather prediction and climate models). An assimilation mode is included for numerical weather prediction and monitoring. In addition to momentum, heat and water fluxes, SURFEX is able to simulate fluxes of carbon dioxide, chemical species, continental aerosols, sea salt and snow particles. The main principles of the organisation of the surface are described first. Then, a survey is made of the scientific module (including the coupling strategy). Finally, the main applications of the code are summarised. The validation work undertaken shows that replacing the pre-existing surface models by SURFEX in these applications is usually associated with improved skill, as the numerous scientific developments contained in this community code are used to good advantage.

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“…Modelling studies of cold cities are focused on a few sites mainly in North America (e.g. Valeo and Ho, 2004;Lemonsu et al, 2010;Leroyer et al, 2010) and Scandinavia (e.g. Semádeni-Davies et al, 1998).…”

Section: Järvi Et Al: Development Of Suews For Cold Climate Citiesmentioning

confidence: 99%

Development of the Surface Urban Energy and Water Balance Scheme (SUEWS) for cold climate cities

et al. 2014

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Abstract. The Surface Urban Energy and Water Balance Scheme (SUEWS) is developed to include snow. The processes addressed include accumulation of snow on the different urban surface types: snow albedo and density aging, snow melting and re-freezing of meltwater. Individual model parameters are assessed and independently evaluated using long-term observations in the two cold climate cities of Helsinki and Montreal. Eddy covariance sensible and latent heat fluxes and snow depth observations are available for two sites in Montreal and one in Helsinki. Surface runoff from two catchments (24 and 45 ha) in Helsinki and snow properties (albedo and density) from two sites in Montreal are also analysed. As multiple observation sites with different land-cover characteristics are available in both cities, model development is conducted independent of evaluation.The developed model simulates snowmelt related runoff well (within 19 % and 3 % for the two catchments in Helsinki when there is snow on the ground), with the springtime peak estimated correctly. However, the observed runoff peaks tend to be smoother than the simulated ones, likely due to the water holding capacity of the catchments and the missing time lag between the catchment and the observation point in the model. For all three sites the model simulates the timing of the snow accumulation and melt events well, but underestimates the total snow depth by 18-20 % in Helsinki and 29-33 % in Montreal. The model is able to reproduce the diurnal pattern of net radiation and turbulent fluxes of sensible and latent heat during cold snow, melting snow and snowfree periods. The largest model uncertainties are related to the timing of the melting period and the parameterization of the snowmelt. The results show that the enhanced model can simulate correctly the exchange of energy and water in cold climate cities at sites with varying surface cover.

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Modeling the Surface Energy Budget during the Thawing Period of the 2006 Montreal Urban Snow Experiment

Cited by 25 publications

References 54 publications

Urban emissions of water vapor in winter

Urban emissions of water vapor in winter

The SURFEXv7.2 land and ocean surface platform for coupled or offline simulation of earth surface variables and fluxes

Development of the Surface Urban Energy and Water Balance Scheme (SUEWS) for cold climate cities

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