1. Environment Canada, Meteorological Service of Canada, S. Bélair, A. Lemonsu, L. Tong, J. Mailhot CRTI Project # 02-0093RD

2. Joint Urban 2003 Experiments GEM-LAM 2.5 km GEM-LAM 1 km GEM-LAM 250 m OKC Incoming flow 15-km Regional model IC + LBC TEB is used in 2.5 km, 1 km, and 250-m models

3. IOP6 (Daytime): Urban Heat Island (1-km Results) Rural Stations Heat Island Index Obs Urban Crops In red, PWIDS stations used for model verification City Center Stations TEB does not make much differences over rural areas (expected!) Significant improvement in the city (cooler in the day, warmer in the night)

4. IOP6 (Daytime): Well-Mixed Layer (1-km Results) Not enough vertical resolution to capture the sharp inversion at the top of the well-mixed layer Model soundings are not sensitive to the inclusion of TEB. Hypothesis is that horizontal variability comes from meteorology

5. IOP9 (Night): Urban Heat Island OKC 50-m Air Temperature (valid at 0500 UTC) Warm plume from the city

6. IOP9 (Night): Shallow Quasi-Neutral Layer ANL (downwind) PNNL (upwind) OBS MODEL OBS MODEL OBS MODEL Norman (rural) Urban soundings Neutral nocturnal layer is well captured by the model. But too warm (not due to city treatment, see sounding at Norman)

7. IOP9 (Night): Daytime turbulence OKC 1000-m Vertical Motion (valid at 2100 UTC) Flow is quasi-laminar in the first portion of the domain (why we use a rectangular domain oriented along the low- level winds)

8. Montreal Urban Snow Experiments (MUSEs) Document the evolution of surface characteristics and energy budgets in a dense urban area during the winter-spring transition –Evolution of snow cover from ~100% to 0% in an urban environment –Impact of snow on the surface energy and water budgets –Quantify anthropogenic heat fluxes in late winter and spring conditions Evaluate the Town Energy Balance model (TEB) in reproducing the surface characteristics and budgets in these conditions Gain expertise in urban measurements OBJECTIVES Residential location: -Horizontally homogeneous -two and three-storey attached buildings - Away from tall buildings and trees, rivers, mountains, parks 1 km MUSE-2005: 17 March to 14 April 2005 MUSE-2006: 10 February to 31 March 2006

9. Measurements During MUSE-2005 ALLEY FABRE STREET Backyard Frontyard Sidewalk Snow TRAILER T air Q air T wall T air Q air T wall Infrared camera Net radiometer 3D sonic anemometer H2O/CO2 analyzer Fine wire thermocouple Anemometer Temperature Humidity IOP: 26-h observing periods with manual measurements Albedo Snow depth Snow density Surfaces temperature Photographs Frontyard Sidewalk Snow depth 20 m Temperature Humidity 4 m Fine wire thermocouple 7 m Manual measurements were also taken on perpendicular street during IOP In blue: continuous measurements

10. An Interesting First Week of Measurements Solar RadiationTurbulent Fluxes As snow melts, there is a rapid decrease of albedo… … associated with an increase of the Bowen Ratio

11. Footprint Analysis 0.0 0.1 0.2 0.3 0.4 Fraction (-) 0.0 0.1 0.2 0.3 0.4 Fraction (-) Vegetation Parks Backyards Borders Sidewalks Roads Alleys Buildings Bld areas Bld polygons Westerly Easterly Similar distributions of surface types over the westerly and easterly footprints. But other factors may influence the turbulent measurements (e.g., installation of instruments on the tower, which is optimal for southwesterly winds).

12. Energy Budget Analysis With snowNo snow RNRN Residue H LE RNRN Residue H LE SS SS LL LL SS SS LL LL Residue = Storage + snow melt – Anthropogenic heat fluxes