Trends in the vertical distribution of ozone: An analysis of ozonesonde data
- Harvard Univ., Cambridge, MA (United States)
The author presents an analysis of trends in ozone since about 1970 and discusses the quality of the ozonesonde data and inconsistencies among data records. In the troposphere there are significant spatial variations in the trends, with largest increases found over Europe ({approximately}2% yr{sup {minus}1} throughout the troposphere) and no long-term trend over Canada; there is a small (<1% yr{sup {minus}1}) increase over the east coast of the United States in summer. The Japanese stations show increases in ozone only below 5.5 km. Trends in surface emissions of NO{sub x} have been similar in the USA, and Western Europe, while the trends in ozone has been larger over Europe; the cause of the large increase in ozone over Europe is unclear. The lack of an ozone increase in the last decade over these two regions during a period of rapid growth of aircraft traffic argues against a significant influence from emissions on NO{sub x} from aircraft. The large interannual variability in ozone in the upper troposphere is similar to that in the lower stratosphere. Any short-term trend in ozone near the tropopause could be caused simply by dynamical factors. Stratospheric ozone decreases are found from about 24 km to near the tropopause. Ozone losses below 17 km appear to be responsible for the 20% difference between trends in column ozone derived from the Stratospheric Aerosol and Gas Experiment and the total ozone mapping spectrometer (TOMS). Ozone changes in the troposphere make an important contribution to the column ozone change for some stations. The stratospheric decreases are larger in winter than in summer over Europe and the midlatitude stations of North America; they are larger in summer than in winter over the high latitude (>53{degrees}N) stations of North America. These seasonal losses are consistent with the patterns reported using TOMS data. Losses are found year round over Syowa, Antarctica, although they are largest in spring. 99 refs., 27 figs., 12 tabs.
- DOE Contract Number:
- FG02-93ER61709
- OSTI ID:
- 114758
- Journal Information:
- Journal of Geophysical Research, Vol. 99, Issue D12; Other Information: PBD: 20 Dec 1994
- Country of Publication:
- United States
- Language:
- English
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