12-14 September, 2011, Lucknow - Earth Science India

National Conference on Science of Climate Change and Earth’s Sustainability: Issues and Challenges ‘A Scientist-People Partnership’
12-14 September, 2011, Lucknow
Ozone Column Contents have shown an overall declining trend of total ozone contends
(TOC) over northern high, mid and low latitude stations. They interpreted their results
based on popular hypothesis of atmospheric dynamics and chemistry coupled processes.
In the present investigation, an attempt has been made to study the long term
changes in TOC over tropical station like Udaipur (Geo. Lat. 24.6° N, Geo. Long. 74°
E, Altitude 580 meter) to find out the basic causes of observed declining trend of TOC
in the present study of the order of .5 t0 .9 Dobson Unit per year over tropical latitude.
More details of the results would be discussed during the presentation.
In the present study, the daily value of TOC at these station collected by TOMS
during the period 2002 to 2010 are used and the monthly median values and its standard
error bars are computed for plotting the variations between their TOC values of
particular months with different years for the two stations. In addition to this, variations
of monthly mean values of contents of other atmospheric parameters like Aerosols
Index at 330 nm, Stratospheric height Zonal Wind, Meridional Wind and Air
Temperature at 10 mbar for the same low latitude as well as same period of study are
also plotted along with monthly TOC variation and are also shown in the same figure to
correlate the long term declining trend of the TOC with these parameters. It is found
that among all the parameters, air temperature at 10 mbar showed the highest positive
correlation coefficient of the order of .76 and lowest for Zonal Wind velocity and least
for AI index at 330 nm and Meridional Wind at 10 mbar.
ANTHROPOGENIC CONTRIBUTION TO THE
COMPOSITE AEROSOL OPTICAL AND RADIATIVE
PROPERTIES OVER DELHI IN THE GANGA BASIN
A.K. Srivastava 1* , Sachchidanand Singh 2 , S. Tiwari 1 and D.S. Bisht 1
1 Indian Institute of Tropical Meteorology (Branch), Prof Ranmath Vij Marg, New Delhi
2 National Physical Laboratory, Dr. K. S. Krishnan Marg, New Delhi
*email: atul@tropmet.res.in
An optically equivalent model has been formulated on the basis of surface
measured aerosol chemical compositions and the retrieved optical aerosol properties
(during the year 2007) over Delhi- a typical urban station in the western part of the
Ganga basin. The measured water-soluble and black carbon (BC) concentrations are
considered to be the main anthropogenic components over the station on the basis of
aerosol chemical compositions; however, the concentrations of insoluble and mineral
dust were decided by varying their concentrations iteratively in the model while
maintaining the mass fraction of BC, so that the model-derived optical properties for
composite aerosols match with the measured one. Further, a different approach in the
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