| MOPITT, James Drummond |
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The Measurements Of Pollution In The Troposphere, or MOPITT,
is also a new type of instrument that provides unique capabilities.
it is a Canadian experiment with an international science team.
Canada contributed the instrument while the U.S. members of the
team are responsible for processing the data.
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MOPITT's goals are to determine the amount of carbon monoxide
at different altitudes in the atmosphere as well as the total amount
in a vertical column, and the total vertical column amount of
methane.
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It derives this information from measurements of infrared radiation
emitted and reflected by the Earth's surface and atmosphere in
eight spectral channels. Because carbon monoxide is present in
only about 1 part in 10 million, we are working with subtle effects
and careful treatment is needed. Today, I will only talk about
MOPITT's Total column carbon monoxide measurements.
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With CO In this plot, showing data collected during 2.5 days in March, red
indicates high carbon monoxide values and blue shows low values.
The smallest units of data are collected in 15-square-mile pixels.
MOPITT sweeps out 600-kilometer wide swaths on each orbit,
leaving gaps for periods of 5 days. Clouds create additional gaps.
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Natural sources of carbon monoxide are emissions associated with
vegetation and fires started by lightning. Human sources include
industrial activity and burning of tropical forests. These are
illustrated in this plot, where there is more carbon monoxide in the
Northern Hemisphere, associated with more industrial activity, than
in the Southern Hemisphere. High values are seen over industrial
areas—North America, Europe, and Southeastern Asia.
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I would particularly like to draw your attention to high values over
West Africa. These are associated with fires that typically occur in
that region at this time of year.
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Finally, I'd like to point out the values above the Indian sub-continent. To the north, the Himalayas are characterized by low
values, but the lower-altitude regions to the south are characterized
by high values that stream out across the Bay of Bengal.
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Carbon monoxide plays a crucial role in the chemistry at lower
altitudes, where it can affect the atmosphere's ability to cleanse
itself and lead to the formation of ozone smog. |
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Future results will show more detail. This in only an introduction
to MOPITT's capabilities. This new information will give us, for
the first time, insights into the global chemistry of the lower
atmosphere.
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