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| Title: | METHANE VMR AND CLIMATOLOGY OF AEROSOLS OVER TROPICAL LATITUDES FROM REMOTE SOUNDERS |
| Authors: | Wondimu, Alemu |
| Advisors: | Dr. Gizaw Mengistu |
| Copyright: | Feb-2009 |
| Date Added: | 8-May-2012 |
| Abstract: | Abstract
The knowledge of the tropospheric concentration distribution of atmospheric trace
gases such as methane and of its temporal evolution allows us to understand chemical
processes controlling the atmospheric composition and to estimate the potential contribution
of each gas to the climate forcing of the Earth-atmosphere system. Equally,
aerosols play an important role in the climate system; the effect of aerosols on the
global climate system is one of the major uncertainties of present climate predictions.
They play a major role in atmospheric chemistry and hence affect the concentrations
of other potentially harmful atmospheric constituents. We have extracted and characterized
the volume mixing ratio(VMR) of methane over the equatorial region from
the spectral records of ground-based high spectral resolution of FTIR. For this work,
the spectral data from the FTIR measurement campaign in October and November
1996 over the Atlantic Ocean covering the region of our study have been used. The
retrieval result has given good quality of methane VMR over most of the regions.
But unhealthy enhancement is seen in the regions 200 South which is attributed to
the poor quality of inputs. In addition, comparison of VMR data of Halogen Occultation
Experiment (HALOE) satellite with our retrieved VMR data from FTIR has
confirmed good agreement over most of the latitude covered by this study and slight
discrepancy at certain latitude. With respect to aerosols, the SAGE II instrument
has collected vertical profiles of stratospheric and tropospheric aerosol extinction at
four wavelengths with high resolution since the program’s inception in October, 1984.
We extracted the aerosol parameter; the aerosol extinction coefficients derived from
version 6.20 series of twenty one years data to characterize the aerosol climatology
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of Africa. Accordingly, from monthly mean extinction profile, we have seen a large
value of aerosol concentration over troposphere of the Northern, Southern and Eastern
regions. Unlike the other two above mentioned regions a large value of aerosol is
observed in the lower stratosphere of Eastern region. These cloud of aerosol extinction
coefficient is observed at the end of winter and during the summer season of the
respective region. |
| URI: | http://hdl.handle.net/123456789/2783 |
| Appears in: | Thesis - Physics
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