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Transcript of Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007 Fei Chen, Mukul Tewari, Miao...
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
Fei Chen, Mukul Tewari, Miao Shiguang,Yubao Liu,
Allen Chan, George Bieberbach, Tom Warner: NCAR
Hiroyuki Kusaka: University of Tsukuba, Japan
Integrated Urban Modeling System for the Community WRF Model: Current Status and Future Plan
OutlineOverview of an urban modeling frameworkExamples of applying this modeling systemFuture work
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
Composite NEXRAD RadarValid 6/8/03 12Z
4 km WRF BAMEX realtime 12-h forecast
Reflectivity
Next-Generation Mesoscale Modeling:
The Weather Research and Forecasting Model (WRF)
• Collaborative partnership, principally among NCAR, NOAA, DoD, FAA, AFWA, and universities.
• WRF development conducted by 15 WRF Working Groups.
• WRF WG 15: land surface model
Goals: Develop advanced mesoscale forecast and assimilation system and accelerate research advances into operations
Integrated WRF Urban Modeling Framework
urban land use characteristics
Surface emission sources
Urbanized high-res land
data assimilation system (u-HRLDAS)
Fine-scale atmospheric analysis (FDDA)
WRF/Noah/Urban coupled modeling system
Computational Fluid Dynamic (CFD) models Transport and Dispersion models Chemistry models
Urban decision support systems
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
Integrate Surface Emission Model MEGAN: Model of Emissions of Gases and Aerosols from Nature
(Guenther 2006)
• Global biogenic emissions model– 1 km2 spatial resolution– Predicts emissions of > 50 BVOC (Biogenic Volatile
Organic Compounds)
Emissioni = AEFi * MEA * WEA * HEA
The Noah Land Surface Model
• Noah LSM primarily for NWP, air pollution, and regional hydrology applications
• Noah in operational models • NCEP WRF-NMM (June 2006)• AFWA: WRF-ARW (July
2006)
• Single layer urban-canopy model (UCM, based on Kusaka 2001)• 2-D urban geometry • Street canyons • Shadowing from buildings
and reflection of radiation
• Anthropogenic heating• Multi-layer roof, wall
and road models
Natural surface
Man-made
surface
Coupled through ‘urban
fraction’
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
Urbanized high-resolution land data
assimilation system (u-HRLDAS)
• No routine high-resolution soil and urban observation for initializing WRF/UCM
• HRLDAS: Using observations to drive LSMs in uncoupled mode– long term evolution of
multi-layer soil moisture, soil temperature, roof/wall/road temperature, surface fluxes, and runoff
4-km HRLDAS surface soil moisturein IHOP domain 12 Z May 29 2002.Chen et al. 2007, J. Appli. Met. Clim.
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
• Both roof and wall temperatures reach equilibrium within a month; roof temperature has fastest spin-up. • However, deep-layer road temperatures still evolve after 30 days.
u-HRLDAS Spin-up
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
U-HRLDAS simulated spatial distribution of roof, wall, and road surface temperature valid at 1 January 2006 for Houston
• Highly dependent on urban types
• Reflecting strong heterogeneity in
urban environments
roof
road
wall
Example of u-HRLDAS
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
Application of Coupled MM5/WRF Urban Models
Houston: Diurnal cycle of wind profile (TexAQS-2000)
Wind Direction
0.0
50.0
100.0
150.0
200.0
250.0
300.0
350.0
400.0
17/10 18/10 19/10 20/10 21/10 22/10 23/10 24/10 25/10 26/10 27/10 28/10 29/10 30/10 31/10 1/11 2/11 3/11
Magenta :ObservationBlue: LSM forecastYellow: MM5 forecast
LSM (with urban modification) capture well the land sea breeze circulation enhanced by urban
(Lowest sigma level)
Hong Kong: 10-day surface wind
Beijing and Tokyo: surface weather, precipitation
Salt Lake City: Diurnal wind direction (URBAN-2000)
Liu, Chen, Warner, and Basara: 2006, J Appli. Meteorol.Lo, Lau, Chen, and Fung, 2007: J. Appli. Meteorol.Lo, Lau, Fung, and Chen, 2006: J Geophys. Res.Zhang, Chen, and Miao 2006: J Geophys. Res., in revision.
Oklahoma City: 2-m temperature (JU-2003)
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
Daunting Challenge: Specify fine-scale urban parameters
• Urban fraction• building height, ZR• roughness for momentum above the urban canopy layer, Z0C• roughness for heat above the urban canopy layer Z0HC• zero-displacement height above the urban canopy layer, ZDC• percentage of urban canopy, PUC• sky view factor, SVF• building coverage ratio (roof area ratio), R• normalized building height, HGT• drag coefficient by buildings, CDS• buildings volumetric parameter, AS• anthropogenic heat, AH• heat capacity of the roof, wall, and road• heat conductivity of the roof, wall, and road• albedo of the roof, wall, and road• emissivity of the roof, wall, and road• roughness length for momentum of the roof, wall, and road• roughness length for heat of the roof, wall, and road
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
Gridded UCM parameters
1, ZR2, Z0C, Z0HC, ZDC3, FRC_URB 4, R, RW5, HGT6, SVF7, AS8, AH: AHB and AHC
CDS, BETR, BETB, BETGCAPR, CAPB, CAPGAKSR, AKSB, AKSGALBR, ALBB, ALBGEPSR, EPSB, EPSGZ0R, Z0B, Z0G, Z0HR, Z0HB, Z0HG
UCM parameters assigned from table (urban_param.tbl)
Example of defining urban parameters
for Beijing
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
WRF/Noah/UCM Model for Beijing Study)
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
WRF/Noah/UCM Model for Beijing Study
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
Sky View Factor (SVF)(45km*36km with 1-km resolution, Min~Max=0.22~1.0 )
1980s 2000
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
AH (Anthropogenic heat)
0800 LST Winter
0800 LST Summer
Winter anthropogenic heating is higher
than summer
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
Diurnal Cycle of AH (Anthropogenic heat)
Summer Winter
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
Spatial Variance of land surface temperature
MODIS Observations
WRF/Noah/UCM simulations
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
30-m Landsat land-cover Houston
Aggregated to WRF 1-km Aggregated to WRF 1-km
domaindomain
Enhance WRF/UCM global land-use data with high-resolution
detailed urban data
WRF/UCM simulated surface wind rotation in Houston for 25 August
2000
Sea-breeze (largely
southerly flow) developed
in opposite direction of
background wind:
Leading to a few hours of
weak wind and accumulation
of pollutants
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
WRF/UCM simulation compared to obs from
wind profiler at Ellington 25 Aug 2000
PBL depthPBL depth
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
• The coupled WRF/Noah/UCM (single-layer) was released in WRF V2.2 (Dec 2006) – Documentation: http://rap.ucar.edu/research/land/technology/urban.php
– Promising to capture fine-scale urban weather phenomena
• Integrating other components (new land-use data, surface BVOC emission model, u-HRLDAS, 2-way coupling with CFD model) are in progress.
• High-resolution land-use data and initialization systems (u-HRLDAS and FDDA) are critical to improving WRF, T&D, and air quality models.
Summary
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
• Conduct uncoupled simulations with different urban models now implemented in WRF
• Improve land use data sets• Test and evaluate new model physics in WRF
• Collaborating with – Bob Bornstein: SJSU– Jason Ching: US EPA– Bill Coirier: CFDRC – Sue Grimmond: King’s College, UK.– Steve Burian: U. Utah
Future Work
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
Future WorkImprove land-use data from global
to urban scales
MODIS vs AVHRRRed: urban areas in the Pearl River Delta, China
1993 USGS data2001 MODIS data
Wind Direction
0.0
50.0
100.0
150.0
200.0
250.0
300.0
350.0
400.0
17/10 18/10 19/10 20/10 21/10 22/10 23/10 24/10 25/10 26/10 27/10 28/10 29/10 30/10 31/10 1/11 2/11 3/11
Magenta :ObservationBlue: LSM forecastYellow: MM5 forecast
The addition of urban treatment is able to capture the land sea breeze circulation enhanced by urban.
Lo, Lau, Chen, and Fung, 2007, JAMC.
(Lowest sigma level)
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
Impacts of land-use change on transport and dispersion Simulated by HPAC (primarily through SCIPUFF)
Nighttime surface dosage
Cultivated
Urban
More Dispersion
Less Advection
Workshop on Model Urbanization Strategy, Exeter, UK. 3-4 May 2007
Future Model Development
• Test a new k- turbulence parameterization in WRF/UCM with emphasis on stable boundary layer processes (Freedman and Jacobson 2003).
• Enhance and test the multi-layer urban canopy model (Martilli-Dupont-EPA, Dupont et al. 2004).
T int
Q wall
Ts roof
Drainage outside the system
Sensible heat flux
Latent heat flux
Net radiation
Storage heat flux
Anthropogenic heat flux
Precipitation
Roughness approach
Root zone layer
Infiltration
Diffusion
Deep soil layer
Drainage
Drainage network
natural soil
roof
water
Paved surface
bare soil
Surface layer
Drag-Force approach
Rn pav Hsens pav LEpav
Gs pav Ts pav
Incorporating Building Morphological Data for Houston
Test Case
Two-way coupling WRF/CFD through MCEL (Model Coupling Environmental Library)
WRF-Noah/UCM coupled model forecast
Down-Scale
Up- Scale
Coupling
CFD-Urban:Hi-Res Urban Model
CFD-Urban: T&D