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Author Srivastava, M. K. ♦ Singh, S. ♦ Saha, A. ♦ Dumka, U. C. ♦ Hegde, P. ♦ Singh, R. ♦ Pant, P.
Source Aryabhatta Research Institute of Observational Sciences (ARIES)
Content type Text
File Format PDF
Language English
Subject Domain (in DDC) Natural sciences & mathematics ♦ Physics
Subject Keyword Solar System ♦ TTropospheric Ultraviolet Visible
Abstract From a high-altitude station, Nainital, India (29.4°N, 79.5°E, 1958 masl), locatedin the central part of lower Himalayas, the observations made during December 2004using a pair of Sun photometers (Microtops II) at wavelengths ranging from 305 to1020 nm are reported. The observed parameters are the direct solar UV irradiance,column ozone, water vapor, and aerosol optical depths (AOD). The results arepresented for the full day clear-sky conditions that prevailed for about 16 days duringthe whole month. It is found that Nainital is a comparatively pristine site with averageAOD at 500 nm ranging between 0.03 and 0.09 and Angstrom exponent generallyclose to 1. The high AOD values occurred on 2 and 25 December due to winds frompopulated north Indian plains as revealed by the Hybrid Single-Particle LagrangianIntegrated Trajectory (HYSPLIT) backward trajectory model. The total column ozonevaries between 251 and 308 DU during the entire period of observations. Themaximum diurnal UV irradiance values in the 2.4 nm bandwidth centered at 305.5,312.5, and 320.0 nm varied between 0.027 and 0.049, 0.15 and 0.20, and 0.29 and0.37 W m-², respectively. The measured UV irradiances are compared with theTropospheric Ultraviolet Visible (TUV) radiation model and show a good agreement.
Part of series jgr03-D08201
Educational Use Research
Education Level UG and PG
Learning Resource Type Article