Urban MeteorologyUrban Meteorology

Rick Peltier

Sangil Lee

Chris Hennigan

Ehsan Arhami

The Urban Heat The Urban Heat IslandIsland

Urban Heat IslandUrban Heat Island The increased air temperatures in urban areas as The increased air temperatures in urban areas as

contrasted to the cooler surrounding rural areas.contrasted to the cooler surrounding rural areas.

Source: Lawrence Berkeley National Lab.

Rapid UrbanizationRapid Urbanization

• Lack of surface water (soil water) and vegetation.

• Low short-wave reflectivity (albedo).

• increased heat release.

Source: EPA & Rice University

Mesoscale circulation and convectionMesoscale circulation and convection

Source: NASA Global Hydrology and Climate Center

Stagnant condition Gradient wind condition

Mesoscale circulation and convectionMesoscale circulation and convection

Source: NASA Global Hydrology and Climate Center

Convective precipitation associated with the excess heat.

Mesoscale circulation and convectionMesoscale circulation and convection

Source: NASA Global Hydrology and Climate Center

• Increased precipitation (7 ~ 50% greater).

• Maximum rainfall rates (48 ~116 % greater) downwind of major cities.

Mean monthly rainfall during the warmer season (May ~ Sept.) from 1998~2000.

Air Quality IssuesAir Quality Issues

Urban heat islands are not only uncomfortably hot, they are also smoggier.(i.e., the incidence of smog increases by 3% per °F above 70°F.)

Source: Heat Island Group, Lawrence Berkeley National Lab. & NASA Global Hydrology and Climate Center

Topographical Effects of Urban Topographical Effects of Urban AreaArea

Urban Pollution Urban Pollution DispersionDispersion

Picture from: corbis.com

OverviewOverview

Effect of Topography on FlowEffect of Topography on Flow

Urban Boundary LayerUrban Boundary Layer

Urban CanopyUrban Canopy

Geographically Modified FlowGeographically Modified Flow

Internal Boundary Layer

fetch

Pictures from: Stull book

Urban Boundary LayerUrban Boundary Layer

Picture from: Fisher et al. report

Sketch of Urban Boundary Layer Sketch of Urban Boundary Layer and Urban Plumeand Urban Plume

Pictures from: Stull book

Layers Within The Urban Boundary Layers Within The Urban Boundary LayerLayer

Picture from: Stull book

What Happens to Wind Profile What Happens to Wind Profile Between the BuildingsBetween the Buildings

Wind Velocity Pollutant Distribution

2 m/s Recirculation eddy

10% of free stream velocity

Pictures from: Gerdes et al., paper

Pollutant Dispersion in Urban Pollutant Dispersion in Urban Street CanopiesStreet Canopies

Large reverse

Pictures from: Xia et al., paper

Identical Building UpstreamIdentical Building Upstream

Low Building Low Building

High BuildingHigh Building

Pictures from: Xia et al., paper

Urban Meteorology – Urban Meteorology – case studiescase studies

Tehran, IranTehran, Iran Graz, AustriaGraz, Austria Sydney, AustraliaSydney, Australia Atlanta, GAAtlanta, GA

Tehran, IranTehran, Iran

From www.lonelyplanet.com

Tehran, IranTehran, Iran

From www.lib.utexas.edu/maps/historical/tehran_iran_1947.jpg

Alborz Mountains

City center

From Asadollah-Fardi

Tehran PollutionTehran Pollution

Valley Pollution DispersionValley Pollution Dispersion

From www.uoregon.edu/dpardue/overheads/mainpage/overheads-entire.html

Valley CirculationValley Circulation

From http://bigmac.civil.mtu.edu/public_html/classes/ce459/study.html

Graz, AustriaGraz, Austria

From www.siteatlas.com

Graz, AustriaGraz, Austria

From www.atlapedia.com

Graz PollutionGraz Pollution

Pollution Event – January 7, 1991Pollution Event – January 7, 1991

PollutantPollutant Max Max ConcentrationConcentration

NONO 0.350 ppm0.350 ppm

NO2NO2 0.110 ppm0.110 ppm

COCO 8 ppm8 ppm

SO2SO2 0.03 ppm0.03 ppm

From Sturm, Almbauer, Kunz

Mountain Lee PhenomenonMountain Lee Phenomenon

From www.atsb.gov.au/public/facts/turbulence.cfm

Sydney, AustraliaSydney, Australia

From http://www.ga.gov.au/map/images.html

Sydney, AustraliaSydney, Australia

From www.ga.gov.au/map.images.html

Sydney PollutionSydney Pollution From 1980 to 1992, Sydney averaged 20 days per year with From 1980 to 1992, Sydney averaged 20 days per year with

peak Opeak O33 > 80 ppb > 80 ppb Diurnal ODiurnal O33 variation variation

From Physick

Sea BreezeSea Breeze

From USA Today

Atlanta, GAAtlanta, GA

50

40

30

20

10Fin

e A

ero

sol M

ass

, µ

g m

-3

7/7/01 7/9/01 7/11/01 7/13/01 7/15/01

Local Time

PM2.5 Sulfate

19:00

19:00

19:00

16:00

19:00

14:00

34.4

34.2

34.0

33.8

33.6

33.4

33.2

33.0

32.8

32.6

32.4

32.2

32.0

-85.5 -85.0 -84.5 -84.0 -83.5 -83.0 -82.5 -82.0

Griffin

Atlanta

coal burning power plants

70

60

50

40

30

20

10

0

Fin

e A

ero

so

l M

ass, µ

g m

-3

8/17/99 8/19/99 8/21/99 8/23/99 8/25/99 8/27/99 8/29/99 8/31/99

Eastern Standard Time

4cB

2s3s

4s

3cC

70

60

50

40

30

20

10

0

Fin

e A

ero

so

l M

ass, µ

g m

-3

8/5/99 8/7/99 8/9/99 8/11/99 8/13/99 8/15/99

Eastern Standard Time

1s

1c2c

A PM2.5Sulfate OC*1.4 EC

Atlanta Supersite, 1999

UGA Agricultural Research Station –

Griffin, GA

The Urban Environment The Urban Environment - Overview- Overview

Regional and local scale models often Regional and local scale models often do not predict very local conditionsdo not predict very local conditions

Urban-Specific ProblemsUrban-Specific Problems

Indoor/Outdoor correlationsIndoor/Outdoor correlations

Socioeconomic status (SES)Socioeconomic status (SES)

Urban ModelingUrban Modeling

Urban ModelingUrban ModelingN

E

S

W8.5 17

Urban-Specific ProblemsUrban-Specific Problems

Local (unmodelled/unmeasured) Local (unmodelled/unmeasured) ExposuresExposures

Urban Heat IslandUrban Heat Island Humidity/Heat IndexHumidity/Heat Index

StressStress Pollutant Specifics and the Urban Pollutant Specifics and the Urban

EnvironmentEnvironment

Urban Health – Air ToxicsUrban Health – Air Toxics

Typically increased (small) local Typically increased (small) local sources of air toxicssources of air toxics• 1,3-Butadiene, benzene, etc1,3-Butadiene, benzene, etc

Very source specificVery source specific

Indoor/Outdoor “Meteorology”Indoor/Outdoor “Meteorology”

Harsh Urban Environment Mitigation Harsh Urban Environment Mitigation (A/C, etc.)(A/C, etc.)

Meteorology drives people inside/outsideMeteorology drives people inside/outside

Meteorological Phenomena Meteorological Phenomena sensitivitysensitivity

Urban Health - SESUrban Health - SES

Urban sites typically populated by Urban sites typically populated by many low-SES familiesmany low-SES families

Low SES = increased susceptibilityLow SES = increased susceptibility

Tehran – ~12,000 persons/sq kmTehran – ~12,000 persons/sq km Graz – 4730 persons/sq kmGraz – 4730 persons/sq km Sydney – 2474 persons/sq kmSydney – 2474 persons/sq km Atlanta – 1303 persons/sq kmAtlanta – 1303 persons/sq km

Our Urban Environment?

Summary/ConclusionsSummary/Conclusions

Urban Heat IslandUrban Heat Island Urban TopographyUrban Topography Case Studies of the Urban Case Studies of the Urban

EnvironmentEnvironment Applications in the Urban Applications in the Urban

EnvironmentEnvironment

ReferencesReferences

1.1. Stull R. B.,Stull R. B., An introduction to boundary layer meteorology An introduction to boundary layer meteorology, Kluwer Academic , Kluwer Academic Publishers, 1988, 596-612.Publishers, 1988, 596-612.

2.2. Fisher B., Kukkonen J. and Schatzmann M., Fisher B., Kukkonen J. and Schatzmann M., Meteorology applied to urban air Meteorology applied to urban air pollution problems COST 715pollution problems COST 715, Report from atmosphericenvironment website., Report from atmosphericenvironment website.

3.3. Gerdes, F., Olivari, D., 1999. Gerdes, F., Olivari, D., 1999. Analysis of pollutant dispersion in an urban street Analysis of pollutant dispersion in an urban street canyoncanyon, Journal of Wind Engineering and Industrial Aerodynamics 82, 105-124., Journal of Wind Engineering and Industrial Aerodynamics 82, 105-124.

4.4. www.corbis.comwww.corbis.com

5.5. Xia J. and LeungXia J. and Leung D.Y.C., Pollutant dispersion in urban street canopies D.Y.C., Pollutant dispersion in urban street canopies, , Atmospheric Environment 35 (2001) 2033-2043.Atmospheric Environment 35 (2001) 2033-2043.

6.6. Asadollah-Fardi, G. “Air Quality Management in Tehran,” www.unescap.orgAsadollah-Fardi, G. “Air Quality Management in Tehran,” www.unescap.org

7.7. Physick, W.L. “Photochemical smog studies in Australian cities,” Physick, W.L. “Photochemical smog studies in Australian cities,” Urban Air Urban Air Pollution, Volume 2Pollution, Volume 2. ed. H. Power and N. Moussiopoulos. Computational . ed. H. Power and N. Moussiopoulos. Computational Mechanics Publications, 1996.Mechanics Publications, 1996.

8.8. Sturm, P.J., R. A. Almbauer, and R. Kunz. “Air quality study for the city of Graz, Sturm, P.J., R. A. Almbauer, and R. Kunz. “Air quality study for the city of Graz, Austria,” Austria,” Urban Air Pollution, Volume1Urban Air Pollution, Volume1. ed. H. Power, N. Moussiopoulos, and . ed. H. Power, N. Moussiopoulos, and C.A. Brebbia. Computational Mechanics Publications, 1994.C.A. Brebbia. Computational Mechanics Publications, 1994.

9.9. Heat Island Group, Lawrence Berkeley National Lab. & NASA Global Hydrology Heat Island Group, Lawrence Berkeley National Lab. & NASA Global Hydrology and Climate Centerand Climate Center

Questions?Questions?

Classmates – Free!Classmates – Free! Dr Wang - $5 per questionDr Wang - $5 per question