Fine Scale Meteorology & Air Quality Models - School of Architecture ...

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ASI2_Lecture 3_7/12/2011 WRF simulations over Madrid (1 km resolutión) 1200 UTC K H Smagorinsky Smagorinsky CONST: With K HO =600 m 2 /s (MM5 style) Temperature (2m) CONST Vertical velocities (250m) Vertical velocity ASI 2: URBAN CLIMATE AND AIR POLLUTION School of Architecture, The Chinese University of Hong Kong, Hong Kong, 7-8 Dec 2011 Alternative methodology: In addition to filtering structures smaller than the grid cell, we also filter turbulent eddies smaller than the size of the most energetic eddies. Because we are running in RANS mode, all turbulence should be filtered out by the turbulence closure scheme. Martilli’s choice is to improve the treatment of the horizontal turbulent transport terms. u uu uv uw P uu uv uw t x y z x x y z Mean advection and pressure: resolved Can we still neglect these terms for high resolution (1km or less) runs Horizontal turbulent transport: neglected Vertical turbulent transport: parameterized Some ad hoc horizontal diffusion is often added Try to parameterize them: if they are not relevant they will show no impact on the ASI 2: URBAN CLIMATE AND AIR POLLUTION School results. of Architecture, The Chinese University of Hong Kong, Hong Kong, 7-8 Dec 2011 22
ASI2_Lecture 3_7/12/2011 Suggested parameterization u u u u K i j 2 Best option would be to treat i j ijtke x j x i 3 As first step, Martilli assumed ui u iuj K Relatively easy to implement in WRF…. x j For “ K” Martilli invoked the Bougeault and Lacarrere scheme, so the vertical diffusion coefficient becomes K z cl boulac tke By analogy, in the horizontal K c maxl , x tke x boulac z zdz tkez down z zdz tkez z o 1/ 2 l upldown minl ,l ASI 2: URBAN CLIMATE AND AIR POLLUTION School of Architecture, The Chinese University of Hong Kong, Hong Kong, 7-8 Dec 2011 z zlup z zl l l boulac g o g up down l up and l down are the distances that a parcel originating from level z, and having the TKE of level z, can travel upward and downward before coming to rest due to buoyancy effects. Application of Filter Option Base New 23
Page 1 and 2: ASI2_Lecture 3_7/12/2011 Croucher A
Page 3 and 4: ASI2_Lecture 3_7/12/2011 Multi-Scal
Page 5 and 6: ASI2_Lecture 3_7/12/2011 PBL scheme
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Page 9 and 10: ASI2_Lecture 3_7/12/2011 Sources of
Page 11 and 12: ASI2_Lecture 3_7/12/2011 HYPOTHESIS
Page 13 and 14: ASI2_Lecture 3_7/12/2011 Geo‐Refe
Page 15 and 16: ASI2_Lecture 3_7/12/2011 Cooling Ca
Page 17 and 18: ASI2_Lecture 3_7/12/2011 Crossroads
Page 19 and 20: ASI2_Lecture 3_7/12/2011 ACM-2 BouL
Page 21: ASI2_Lecture 3_7/12/2011 erturbatio
Page 25 and 26: ASI2_Lecture 3_7/12/2011 Sensitivit
Page 27 and 28: ASI2_Lecture 3_7/12/2011 Dependence
Page 29 and 30: ASI2_Lecture 3_7/12/2011 HCHO Histo
Page 31 and 32: ASI2_Lecture 3_7/12/2011 SGV parame

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