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