will pendergrass noaa/arl/atdd oar senior research council meeting oak ridge, tn august 18-19, 2010...
TRANSCRIPT
Will Pendergrass
NOAA/ARL/ATDD
OAR Senior Research Council Meeting
Oak Ridge, TN
August 18-19, 2010
Boundary–Layer Dispersion
Urban Meteorology
04/18/23 Air Resources Laboratory
04/18/23 Air Resources Laboratory
The DCNet Urban Testbed
04/18/23 Air 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!
0 2000 4000 6000
0
400
800
1200
1600
2000
0.0001
0.001
0.01
0.1
1
10
100
mg
/m**
3
IDLH = 30 mg/m**3
PEL = 3 mg/m**3
5 degrees15 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
04/18/23 Air Resources Laboratory
Current
DCNet Stations
2 km5 km
04/18/23 Air Resources Laboratory
04/18/23 Air Resources Laboratory
Urban Complications
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DCNet Enhanced NAM12 plume and trajectory
DCNet Non-Enhanced NAM12 plume and trajectory
Do UrbanObservations
Make aDifference?
HYSPLIT4 Simulations
04/18/23 Air Resources Laboratory
>0 - 1
>1 - 3
>3 - 5
>5 - 7
>7 - 10
>10 - 15
0 % 5 % 1 0 % 1 5 %
0 % 5 % 1 0 % 1 5 %
0 % 5 % 1 0 % 1 5 %
0 % 5 % 1 0 % 1 5 %
Urban Climatology
04/18/23 Air Resources Laboratory
Q = K ↓- K ↑ +L ↓ - L ↑ = QH + QE + ∆QS
1 2 3 4 5 6 7 8 9 10 11 12
Month
-3
-2
-1
0
1
2
3
Te
mp
erat
ure
Dif
fere
nce
(oC
)
Night
Day
Mean Temperature DifferencesUrban - Rural
Sensible Heat Flux
Urban Heat Island
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Urban Velocity Profiles
Observed Profiles
Modeled
Apparent Flow Regime
04/18/23 Air Resources Laboratory
04/18/23 Air 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?
04/18/23 Air Resources Laboratory
Urban Canopy ModelStudy 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"
04/18/23 Air Resources Laboratory
Calnex PasadenaMonitoring Station
Keck Laboratories
CalNex: Pasadena
04/18/23 Air Resources Laboratory
Estimating sensibleheat flux from
surface temperatures
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Urban friction coefficient: Cf
Skimming Flow
CalNex: Pasadena DCNet: Federal Triangle
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• 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
04/18/23 Air 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 MeteorologyFuture Directions