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Mori, K., and T. Sato, 2015: Evaluating the role of snow cover in urban canopy layer on the urban heat island in Sapporo, Japan with a regional climate model. J. Meteor. Soc. Japan, 93, 581-592.
https://doi.org/10.2151/jmsj.2015-039

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Highlights:

• This study assesses the effect of snow cover in urban canopy on winter heat islands using the Weather Research and Forecasting Model coupled with an urban canopy model.
• A sensitivity test with realistic snow cover run (CTL) and snow-free urban run (NO_SNOW_UCM) reveals that snow cover in urban areas acts to decrease surface air temperature (Fig. 1), with a stronger decrease in daily maximum temperatures (0.4−0.6 °C) than daily minimum temperatures (0.1−0.3 °C).
• The increase in surface albedo due to snow cover is primarily responsible for the decrease in net shortwave radiation and the sensible heat flux. In addition, increased evaporation causes a weakened sensible heat flux. The decrease in sensible heat flux at 1200 JST (50.6 W m⁻²) is comparable magnitude to the anthropogenic heat release.
• Snow cover on the building roofs reduces surface air temperature because of sensible heat flux decrease (43.1 W m⁻²), corresponding to 85% of the total sensible heat flux decrease at 1200 JST in the UCM (Fig. 2).