Volume 5, No. 1, June 2005, Pages 103-114 PDF(369 KB)
A Four-Year Climatology of Total Column Tropical Urban Aerosol, Ozone and Vapor Distributions over Pune, India
P.C.S. Devara, S.K. Saha, P. Ernest Raj, S.M. Sonbawne, K.K. Dani, Y.K. Tiwari, R.S. Maheskumar
Physical Meteorology and Aerology Division, Indian Institute of Tropical Meteorology, Dr. Homi Bhabha Road, NCL Post Office, Pashan, Pune 411 008, India
The total column aerosol optical depth, ozone and water vapor using a MICRO-processor based Total Ozone Portable Spectrometer (MICROTOPS II) and its sun photometer version have been routinely measured at the Indian Institute of Tropical Meteorology (IITM), Pune (18° 32' N, 73° 51' E, 559 m above mean sea level), India, with a view to establish an aerosol climatology over this fast growing tropical urban station. This paper focuses on spectral-temporal variations, inter-annual variability and long-term trends in the above aerosol and pre-cursor gas distributions over Pune. Besides a strong wavelength dependence of aerosol optical depth (AOD), the radiometer derived total column ozone values are found to correlate well with those estimated from the NASA’s Earth Probe, Total Ozone Mapping Spectrometer (TOMS) satellite observations during the study period. The results also indicate a decreasing trend in all the above parameters, possibly due to absorbing anthropogenic aerosols during the study period, and lower Angstrom exponent, implying the prevalence of coarse-mode aerosol particles, originating from marine air mass, from around May to July, which is consistent with the ratio between the optical depths measured at 1020 and 380 nm.
Aerosols and gases; multi-channel solar radiometer; optical extinction; climatological trends; urbanization.