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A. Ghazi, Pi-Huan Wang, and M. P. McCormick

Abstract

Satellite ozone observations made by the Stratospheric Aerossol and Gas Experiment (SAGE) and corresponding meteorological temperature data are used to study the radiative damping processes associated with planetary waves during stratospheric warmings. Ramanathan's model has been adapted fox. the radiative heating and cooling calculations. The derived infrared damping coefficients, based on observed stratospheric ozone and temperature, are compared with the Newtonian cooling coefficients of Dickinson and Fels. It is also shown that the negative correlation between temperature and ozone solar heating in the upper stratosphere accelerates the damping rate due to infrared cooling alone, in agreement with the theoretical analysis and an earlier report based on observations. In addition, it is also found in this analysis that the phase relationship between ozone and solar heating waves is characterized by its behavior in three distinct layers. In the regions above about 2 mb and also below about 10 mb, the waves are closely in-phase. Between approximately 2 and 10 mb, they show a departure from the in-phase relationship which can be attributed to the so-called “opacity effect.” This effect significantly determines the magnitude of radiative damping.

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Pi-Huan Wang, M. P. McCormick, and W. P. Chu

Abstract

Ozone data from the Stratospheric Aerosol and Gas Experiment (SAGE) have been used in conjunction with meteorological information to study the ozone transport near 55°N due to planetary waves during the late February 1979 stratospheric warming. The results indicate an intense poleward eddy ozone transport in the middle stratosphere between ∼24 and 38 km altitudes and an equatorward transport above an altitude of ∼38 km. It is found that this equatorward eddy ozone transport in the upper stratosphere was accompanied by a poleward eddy heat transport, as expected on the basis of the ozone photochemistry. The results also show an equatorward eddy ozone transport in the lower stratosphere (below ∼25 km), but it is secondary. The transport effect of wavenumber 2 can account for a major portion of the net eddy ozone flux during this late February 1979 warming.

The phase relationship between temperature, meridional velocity and ozone mixing ratio waves has also been examined. Overall, the results agree qualitatively with existing model analyses. In the lower stratosphere, the temperature and ozone waves are found to be nearly in-phase. They are approximately out-of-phase in the upper stratosphere. A transition region is shown in between. However, this transition region is thinner and centered at a slightly lower altitude than that predicted in the model analyses of Hartmann and Garcia, Kawahira and those reported by Gille et al. The reason for this difference is discussed.

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Pi-Huan Wang, Adarsh Deepak, and Siu-Shung Hong

Abstract

Formulas that can be used to determine the optical path between two points along an atmospheric ray path are derived for the case when the local zenith angle of the ray path is larger than 70°. For angles less than 70°, these formulas reduce to the airmass function; viz., the secant of the zenith angle. The formulation presented in this paper is genera] enough to be applicable to a wide variety of atmospheric conditions, such as spherical and nonspherical atmospheres, and vertically and horizontally homogeneous as well as inhomogeneous atmospheres. Formulation for the case when atmospheric refraction is important also is presented here.

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Pi-Huan Wang, Siu-Shung Hong, Mao-Fou Wu, and Adarsh Deepak

Abstract

The temporal and spatial variations of the zonally-averaged ozone beating rate in the middle atmosphere on a global scale are investigated in detail based on a model study. This study shows that the mean ozone heating rate calculation can be made in a realistic manner by taking advantage of the existing two-dimensional ozone distribution and including the effect of the sphericity of the earth's atmosphere. The obtained ozone heating rates have also been Fourier-analyzed. The common features of the first three harmonic components which correspond respectively to the annual, semiannual and terannual variations are (1) the local maximum amplitudes are located in the altitude regions between 45 and 57 km; (2) local maximum amplitude can be found in the polar region; and (3) maximum horizontal gradients of the beating rate are concentrated in the high latitudes from 60 to 90°. It is also found that the amplitude of the second Fourier component at the pole is about six times greater than that at the equator.

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