Transcript PRESENTATION NAME

Featured Articles:
New Directions: The growing urban heat
and pollution ‘‘island’’ effect—impact on
chemistry and climate
(Crutzen 2004)
Suppression of Rain and Snow by
Urban and Industrial Air Pollution
(Rosenfeld 2000)
By: Jay Shelton
Major: Atmospheric Sciences
What is an urban heat island (UHI)?
 Tendency for large cities to to be warmer than
surrounding, less metropolitan areas.
+
=
 Increased SW absorption caused by
canyon geometry (increased area and
multiple reflection)
 Decreased LW loss caused by canyon
geometry
 Increased greenhouse effect caused
by air pollution
 Anthropogenic heat source
 Increased sensible heat storage
caused by construction materials
 Decreased latent heat flux caused by
change of surface type
 Decrease sensible and latent heat
fluxes caused by canyon geometry
(reduction of wind speed)
“Canyons” between buildings
Human Energy Production
 Sun supplies 235 W/m^2 of energy annually.
 Human energy production (HEP)
 On average, annual HEP is .025 W/m^2.
 Yes, that even includes the heat from our bodies.
 Some densely populated and highly industrialized areas are
known to output up to 70 W/m^2 of energy annually due to the
release of high concentrations of air pollutants and CO2 from
the burning of fossil fuels.
 High density of pollutants from
urban areas will affect atmospheric
chemistry and climate.
 These effects could be
far-reaching.
What effect can pollution in the UHI have on certain meteorological events?
 Increased lightning flash frequency. (In need of further study)
 Changes in cloud chemistry
 Particulates acting as cloud condensation nuclei
• Inefficient coalescence
• Smaller cloud droplets
 Suppression of rain formation
• Decreased precipitation
.
r > 14 μm
r < 14 μm
Droplets are
able to coalesce
and fall.
Droplets are
unable to fall.
 Satellites have been monitoring ship stacks, mineries and factories
in urban/industrial areas.
 Thick concentrations of pollutants seen in stratocumulus clouds.
 Pollution tracks
• Provides the first evidence that these particulates are
changing cloud microstructure.
N
N
Urban air pollution from
Istanbul (1), Izmut (2), and Bursa (3).
Impact of effluents from the Hudson
Bay Mining and Smelting compound
at FlinFlon in Manitoba (4).
N
Pollution tracks originating from the Port Augusta
power plant (5), the Port Pirie lead smelter (6),
Adelaide port (7), and oil refineries (8).
7
6
1
5
2
3
4
14 μm threshold
 Numerous satellite images were taken.
 All images showed pollution tracks originating
from pollution sources in the region.
 Cloud top temperatures were conducive to the
precipitation formation process, but because of
the high concentrations of aerosols, rain was
not always able to fall.
 These results should not be surprising:
 Port Augusta – 520 MW Power plant operating on
brown coal.
 Port Prairie – Worlds largest lead smelter and
refinery.
 Other sources of pollution originate from a cement
plant and oil refineries in certain regions.
 What is Surprising:
 Australia is probably the least (inhabited) polluted
continent on Earth.
 Satellite imagery has shown that pollution in the atmosphere can
act as an inhibitor for precipitation.
 Too many particulates acting as cloud condensation nuclei
 Inefficient coalescense (smaller droplet sizes)
 Less rainfall
 Less precipitation in a certain area means that there is less
available water to evaporate.
 Extra heating at the surface
 Higher temperatures
 Enhancement of the urban heat island effect
 Population is rapidly increasing
 New urban development
 Increasing output of energy/pollution
Are there any solutions or remedies that exist?
 Emission controls
 Capping policies
 Removal methods to rid pollutants from the
atmosphere
 Smokestack scrubbers
 More plant life in cities
 Implementation of hybrid cars