Environmental Data Analysis BC ENV 3017
Atmospheric Transport
(NOx/VOCs)(Globe)(highs)
(lows)
(land/sea breeze)(Inversions)(RH)
Why chemical concentrations vary in the environment
sources/sinks
chemistry
transport
Scales of atmospheric movement and characteristic flow
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large scale weather systems
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global heat balance requires transport of latent and sensible heat towards
the poles (Fig)
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coriolis force affects air flow => deflection to the right (left) on northern
(southern) hemisphere
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dominant large scale winds are predictable as a function of latitude and
altitude and form distinct climatic regions on the globe (Fig)
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regional wind patterns
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air flow driven by regional differences in heating (fig)
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on regional scales the specific location of the jet stream or steering
winds can have a great impact on weather patterns and flow fields (fig)
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in eastern North America, the jet stream varies in location (fig).
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characteristic weather patterns that form in response to both high presssure
and low pressure systems are a consequence of these forces (fig;
fig).
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local winds
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heat capacity differences between adjacent land and water masses causes
differential heating
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=> land - sea breezes are important winds in coastal regions (fig).
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topography - valley and mountains
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=> modification of local winds (fig;
fig)
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this is evident in the Hudson Valley (fig).
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inversions can trap pollutants
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the mixing height is an important determinant of atmospheric pollutant
concentrations.
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temperature inversions can limit dispersiondramatically (fig).
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this inversions occur frequently in our area at night
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relative humidity
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water vapor pressure as a function of temperature (svp = saturation
water vapor pressure) (Fig),
can explain many phenomena in the atmosphere.
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absolute humidity (or water vapor mixing ratio): mass of
vapor per unit volume of air, in g m-3
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at 30oC, air has a svp of 42.43 hPa (hPa = mbar) and can contain
up to 30 g m-3, at 0oC svp is only 4.5 g m-3
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relative humidity: actual water vapor pressure / svp in %; or: actual
water vapor content / absolute humidity
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today's weather
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