Urban Meteorology

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Urban Meteorology
Rick Peltier Sangil Lee
Chris Hennigan Ehsan Arhami
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The Urban Heat Island
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Urban Heat Island

• The increased air temperatures in urban areas as
  contrasted to the cooler surrounding rural areas.

Source Lawrence Berkeley National Lab.
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Rapid Urbanization

• Lack of surface water (soil water) and
  vegetation.
• Low short-wave reflectivity (albedo).
• increased heat release.

Source EPA Rice University
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Mesoscale circulation and convection
Gradient wind condition
Stagnant condition
Source NASA Global Hydrology and Climate Center
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Mesoscale circulation and convection
Convective precipitation associated with the
excess heat.
Source NASA Global Hydrology and Climate Center
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Mesoscale circulation and convection

• Mean monthly rainfall during the warmer season
  (May Sept.) from 19982000.

• Increased precipitation (7 50 greater).
• Maximum rainfall rates (48 116 greater)
  downwind of major cities.

Source NASA Global Hydrology and Climate Center
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Air 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 70F.)
Source Heat Island Group, Lawrence Berkeley
National Lab. NASA Global Hydrology and Climate
Center
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Urban Pollution Dispersion

• Topographical Effects of Urban Area

Picture from corbis.com
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Overview

• Effect of Topography on Flow
• Urban Boundary Layer
• Urban Canopy

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Geographically Modified Flow
Pictures from Stull book
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Urban Boundary Layer
Picture from Fisher et al. report
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Sketch of Urban Boundary Layer and Urban Plume
Pictures from Stull book
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Layers Within The Urban Boundary Layer
Picture from Stull book
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What Happens to Wind Profile Between the Buildings
Wind Velocity
Pollutant Distribution
Pictures from Gerdes et al., paper
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Pollutant Dispersion in Urban Street Canopies
Pictures from Xia et al., paper
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Identical Building Upstream

• Low Building

• High Building

Pictures from Xia et al., paper
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Urban Meteorology case studies

• Tehran, Iran
• Graz, Austria
• Sydney, Australia
• Atlanta, GA

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Tehran, Iran
From www.lonelyplanet.com
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Tehran, Iran
Alborz Mountains
From www.lib.utexas.edu/maps/historical/tehran_ira
n_1947.jpg
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Tehran Pollution
From Asadollah-Fardi
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Valley Pollution Dispersion
From www.uoregon.edu/dpardue/overheads/mainpage/ov
erheads-entire.html
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Valley Circulation
From http//bigmac.civil.mtu.edu/public_html/class
es/ce459/study.html
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Graz, Austria
From www.siteatlas.com
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Graz, Austria
From www.atlapedia.com
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Graz Pollution

• Pollution Event January 7, 1991

Pollutant Max Concentration
NO 0.350 ppm
NO2 0.110 ppm
CO 8 ppm
SO2 0.03 ppm
From Sturm, Almbauer, Kunz
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Mountain Lee Phenomenon
From www.atsb.gov.au/public/facts/turbulence.cfm
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Sydney, Australia
From http//www.ga.gov.au/map/images.html
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Sydney, Australia
From www.ga.gov.au/map.images.html
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Sydney Pollution

• From 1980 to 1992, Sydney averaged 20 days per
  year with peak O3 gt 80 ppb
• Diurnal O3 variation

From Physick
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Sea Breeze
From USA Today
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Atlanta, GA
Atlanta Supersite, 1999
UGA Agricultural Research Station Griffin, GA
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The Urban Environment - Overview

• Regional and local scale models often do not
  predict very local conditions
• Urban-Specific Problems
• Indoor/Outdoor correlations
• Socioeconomic status (SES)

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Urban Modeling
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Urban Modeling
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Urban-Specific Problems

• Local (unmodelled/unmeasured) Exposures
• Urban Heat Island
• Humidity/Heat Index
• Stress
• Pollutant Specifics and the Urban Environment

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Urban Health Air Toxics

• Typically increased (small) local sources of air
  toxics
• 1,3-Butadiene, benzene, etc
• Very source specific

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Indoor/Outdoor Meteorology

• Harsh Urban Environment Mitigation (A/C, etc.)
• Meteorology drives people inside/outside
• Meteorological Phenomena sensitivity

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Urban Health - SES

• Urban sites typically populated by many low-SES
  families
• Low SES increased susceptibility

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Our Urban Environment?

• Tehran 12,000 persons/sq km
• Graz 4730 persons/sq km
• Sydney 2474 persons/sq km
• Atlanta 1303 persons/sq km

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Summary/Conclusions

• Urban Heat Island
• Urban Topography
• Case Studies of the Urban Environment
• Applications in the Urban Environment

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References

• Stull R. B., An introduction to boundary layer
  meteorology, Kluwer Academic Publishers, 1988,
  596-612.
• Fisher B., Kukkonen J. and Schatzmann M.,
  Meteorology applied to urban air pollution
  problems COST 715, Report from atmosphericenvironm
  ent website.
• Gerdes, F., Olivari, D., 1999. Analysis of
  pollutant dispersion in an urban street canyon,
  Journal of Wind Engineering and Industrial
  Aerodynamics 82, 105-124.
• www.corbis.com
• Xia J. and Leung D.Y.C., Pollutant dispersion in
  urban street canopies, Atmospheric Environment 35
  (2001) 2033-2043.
• Asadollah-Fardi, G. Air Quality Management in
  Tehran, www.unescap.org
• Physick, W.L. Photochemical smog studies in
  Australian cities, Urban Air Pollution, Volume
  2. ed. H. Power and N. Moussiopoulos.
  Computational Mechanics Publications, 1996.
• Sturm, P.J., R. A. Almbauer, and R. Kunz. Air
  quality study for the city of Graz, Austria,
  Urban Air Pollution, Volume1. ed. H. Power, N.
  Moussiopoulos, and C.A. Brebbia. Computational
  Mechanics Publications, 1994.
• Heat Island Group, Lawrence Berkeley National
  Lab. NASA Global Hydrology and Climate Center

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Questions?

• Classmates Free!
• Dr Wang - 5 per question