Earth Observations from Space The First 50 Years of Scientific Achievements (2008) / Chapter Skim
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5 Atmospheric Composition: Ozone Depletion and Global Pollution
5 Atmospheric Composition: Ozone Depletion and Global Pollution
Pages 37-49
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From page 37... ...
Given ozone's importance part, tropospheric ozone levels are strongly influenced by to the atmospheric composition and temperature structure photochemical reactions involving nitrogen oxides and and as Earth's UV shield, it is critical to measure its global hydrogen oxides and by ozone inputs from the stratosphere. distribution; understand its trends and the mechanisms that In the presence of elevated nitrogen oxides from localized control its distribution; and understand its interactions with sources of pollution, hydrocarbons -- even the ubiquitous atmospheric chemistry, dynamics, and the climate system.
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From page 38... ...
Subsequent studies showed that bromine, which the amount of stratospheric ozone by a factor of 2. Further has natural and anthropogenic sources, could also cause laboratory measurements showed that reactions involving significant ozone depletion (Wofsy et al.
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From page 39... ...
. shed light on the global distribution of stratospheric ozone The understanding of atmospheric dynamics was revolu- were the backscattered ultraviolet (BUV)
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From page 40... ...
In 1991 the Microwave Limb Sounder (MLS) on the Upper Atmosphere Research Satellite (UARS)
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From page 41... ...
FIGURE 5.2 Time series of zonal mean water vapor profile measurements by the Microwave Limb Sounder on the Aura satellite. The colors represent a percentage change relative to the 15° S-15° N mean at each pressure level.
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From page 42... ...
. The monthly mean ozone column over Antarctica sphere in spring, where the ozone hole formed (Figure 5.3; provides information on the evolution of the Antarctic ozone Waters et al.
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From page 43... ...
Hemisphere In conclusion, satellite observations provided the first Although the Antarctic ozone hole is the better-known measurements of the global vertical, horizontal, and temporal phenomenon that has illuminated and confirmed the theory distributions of ozone and dynamical variables in the stratoof halogen-catalyzed chemical ozone destruction, a more sphere, permitting the monitoring of their long-term changes. important question from a societal point of view is the effect By allowing verification of the factors causing those changes, of anthropogenic chlorine, bromine, and other gases on satellite observations were critical in confirming the seriousthe ozone concentrations over heavily populated nonpolar ness of the danger posed by the release of anthropogenic latitudes.
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From page 44... ...
Differencing the total and the stratospheric ozone column amount to deduce a "tropospheric residual" is possible due to the observation that stratospheric ozone TROPOSPHERIC OZONE AND TRACE GASES is zonally invariant in the tropics and changes slowly over week-to-month timescales. Thus, a stratospheric profiler like The troposphere presents special challenges to passive (SAGE, later SBUV, HALOE, and MLS)
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From page 45... ...
greater than that over the Pacific. inspection of tropospheric ozone maps showed the South Interestingly, the Atlantic tropospheric ozone maximum Atlantic maximum was year-round, exemplified by the sois largest at the end of the southern hemisphere biomass called tropical ozone paradox, named for the persistence of burning season, from August through November.
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From page 46... ...
, ozone, and smoke to A time series of tropospheric ozone derived from TOMS discriminate local and imported pollution for regulatory back to 1980 showed signatures of ENSO events in the 1980s purposes (Morris et al. 2006, Pierce et al.
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From page 47... ...
GOME and OMI NO2 appears most intense in industrial ozone in the "paradox" region of the South Atlantic (Edwards regions compared to biomass burning, but it shows up during et al.
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From page 48... ...
In addition to chemical production, northern hemisphere pollution sources are predominantly urban and industrial, while high CO in the tropics and 5-9 southern hemisphere often results from biomass burning. NOTE: ppbv = parts per billion by volume.
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From page 49... ...
. Reactions with highly saline Although satellite measurements of tropospheric species surface associated with annual sea ice are now believed to are more difficult, rapid advances in measurements of tropobe the source of airborne labile halogen compounds, which spheric composition are providing insights into the sources, cause the surface ozone depletion (Rankin et al.
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