Will Pendergrass NOAA/ARL/ATDD OAR Senior Research Council Meeting Oak Ridge, TN August 18-19, 2010 Boundary–Layer Dispersion Urban Meteorology 5/20/2015Air Resources Laboratory

5/20/2015Air Resources Laboratory The DCNet Urban Testbed

5/20/2015Air Resources Laboratory Why Urban Micrometeorology? The lowest layers of the Atmosphere are in direct contact with where people work, play, live. Hence, we need to understand atmospheric flow behavior over various terrain, especially over populated regions! Dispersion forecast models mainly rely on parameterizations and relations derived from research over “ideal” (i.e., rural, flat, homogeneous) terrain. We need to generate improved parameterizations to help models perform better over complex urban areas! Improving parameterizations means collecting measurements! m g / m * * 3 IDLH = 30 mg/m**3 PEL = 3 mg/m**3 5 degrees 15 degrees 25 degrees

DCNet is a NOAA dispersion forecasting program, intended to (a) to determine how best to make use of local data in order to derive an acceptably accurate product and (b) to provide DC with the best possible dispersion forecasting system. DCNet 5/20/2015Air Resources Laboratory

Current DCNet Stations 2 km5 km 5/20/2015Air Resources Laboratory

5/20/2015Air Resources Laboratory Urban Complications

5/20/2015Air Resources Laboratory DCNet Enhanced NAM12 plume and trajectory DCNet Non-Enhanced NAM12 plume and trajectory Do Urban Observations Make a Difference? HYSPLIT4 Simulations

5/20/2015Air Resources Laboratory Urban Climatology

5/20/2015Air Resources Laboratory Q = K ↓- K ↑ +L ↓ - L ↑ = Q H + Q E + ∆Q S Sensible Heat Flux Urban Heat Island

5/20/2015Air Resources Laboratory Urban Velocity Profiles Observed Profiles Modeled

Apparent Flow Regime 5/20/2015Air Resources Laboratory

5/20/2015Air Resources Laboratory 2010 CalNexus Science Questions Transport and Meteorology Goal: Improved Urban Canopy Layer Parameterizations How best can we characterize and model air flow over coastal waters and the complex terrain of California? What are the major deficiencies in the representation of chemistry and meteorology in research and operational models and how can models be improved through the collection of additional measurements? What physical and chemical processes are not captured well by available models? Is there an optimum grid resolution to capture all of the relevant physical and chemical processes that occur?

5/20/2015Air Resources Laboratory Urban Canopy Model Study Focus Urban State Variables "URBAN ROOF SKIN TEMPERATURE" "K" "URBAN WALL SKIN TEMPERATURE" "K" "URBAN ROAD SKIN TEMPERATURE" "K" "URBAN CANOPY TEMPERATURE" "K" "URBAN CANOPY WIND SPEED" "K" "URBAN CANOPY HUMIDITY" "kg kg{-1}" "M-O LENGTH ABOVE URBAN ROOF" "dimensionless" "M-O LENGTH ABOVE URBAN WALL" "dimensionless" "M-O LENGTH ABOVE URBAN ROAD" "dimensionless" "M-O LENGTH ABOVE URBAN CANOPY" "dimensionless" "ROOF LAYER TEMPERATURE" "K" "WALL LAYER TEMPERATURE" "K" "ROAD LAYER TEMPERATURE" "K" "SENSIBLE HEAT FLUX FROM URBAN SFC" "W m{-2}" "LATENT HEAT FLUX FROM URBAN SFC" "W m{-2}" "GROUND HEAT FLUX INTO URBAN" "W m{-2}" "NET RADIATION ON URBAN SFC" "W m{-2}" "COS of SOLAR ZENITH ANGLE" "dimensionless" "SOLAR HOUR ANGLE" "dimensionless" "SOLAR DECLINATION" "dimensionless"

5/20/2015Air Resources Laboratory Calnex Pasadena Monitoring Station Keck Laboratories CalNex: Pasadena

5/20/2015Air Resources Laboratory Estimating sensible heat flux from surface temperatures

5/20/2015Air Resources Laboratory Urban friction coefficient: C f Skimming Flow CalNex: Pasadena DCNet: Federal Triangle

5/20/2015Air Resources Laboratory Meteorological data transferred to community ftp site Abstract submitted for AGU special session High frequency spectral data in review Complete energy balance components in review CalNex Status

5/20/2015Air Resources Laboratory Conduct research over other types of terrain such as suburban regions, coastal cities, etc… Assess changes in turbulent flow along transects from suburban to urban to suburban. Assess spatial variability of vertical profiles of mean winds and turbulence; mobile remote sensing. Observe the budget of TKE: Does the oft-used “local dissipation” assumption for turbulence (rates of mechanical and buoyant production equals rate of viscous dissipation) hold above the urban canopy? Urban Meteorology Future Directions