A short overview article by Richard Kerr (Science, 2007) well encapsulates the global dimensions and potential impacts of pollutant hazes and their climate-changing reach. Alluded to are conceivable changes to the atmospheric general circulation, oceanic currents, and through radiative and other feedbacks on precipitating cloud systems aerosols pollution can enhance, reduce, or delay the effects ofgreenhouse gas global warming. Much as an El Nino's tropical warmth can form an 'atmospheric bridge' to change the weather patterns in distant locations, the article implies that pollutants and their transport lead to global-scale teleconnections through their interaction with the global water and energy cycle. While there have been several studies (observational and modeling) of such interactions, the global dimensions of the interactions of dust, aerosols, and pollutants have only recently been conceptualized with the advent of new satellite sensors on board the current generation of satellite systems. It is to be noted, however, that several aspects of these interactions remain elusive, and more detailed analysis and modeling is required to better quantify their dynamics and energetics.
NASA's Terra spacecraft provides a complete view ever of the world's air pollution traveling through the atmosphere, across continents and oceans. For the first time, policymakers and scientists now have a way to identify the major sources of air pollution and to closely track where the pollution goes, anywhere on Earth. Carbon monoxide is a gaseous by-product from the burning of fossil fuels, in industry and automobiles, as well as burning of forests and grasslands. In the 30 April 2000 image (Figure 10), the levels of carbon monoxide are much higher in the Northern Hemisphere, where human population and human industry is much greater than in the Southern Hemisphere. However, in the 30 October 2000 image, immense plumes of the gas are emitted from forest and grassland fires burning in South America and Southern Africa. Researchers were surprised to discover a strong source of carbon monoxide in Southeast Asia. The air pollution plume from this region moves over the Pacific Ocean and reaches North America, frequently at fairly high concentrations. While fires are the major contributor to these carbon monoxide plumes, it is suspected that, at times, industrial sources may also be a factor.
The movements of carbon monoxide around the globe are particularly striking when viewed as a movie spanning a 10-month period. The following web sites contain animations of the images taken by MOPITT (Measurements of Pollution in the Troposphere) sensor for the Pacific, the Southern Hemisphere, and the globe, respectively: http://www.gsfc.nasa.gov/gsfc/earth/pic-tures/terra/pacific.mpeg, www.gsfc.nasa.gov/gsfc/earth/ pictures/terra/southam.mpeg, and http://veimages.gsfc. nasa.gov/1788/mopitt_first_yeara.mpg.
The global air pollution monitor onboard Terra is the innovative MOPITT sensor, which was contributed to the Terra mission by the Canadian Space Agency. The instrument was developed by Canadian scientists at the
30 October 2000
Carbon monoxide concentration (ppb) ^ — I
Figure 10 Images of global carbon monoxide observed by the MOPITT (measurements of pollution in the troposphere) sensor on board NASA's Terra satellite. The false colors in these images represent levels of carbon monoxide in the lower atmosphere, ranging from about 390 ppb (dark brown pixels), to 220 ppb (red pixels), to 50 ppb (blue pixels). Credit: Images and animations courtesy NASA GSFC Scientific Visualization Studio, based on data from MOPITT (Canadian Space Agency and University of Toronto). http:// visibleearth.nasa.gov/view_rec.php?vev1id=8086.
University of Toronto and built by COM DEV International of Cambridge, Ontario. The data were processed by a team at the US National Center for Atmospheric Research (NCAR), at Boulder, CO.
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