Seasonal and solar activity variation of NO₂ over Ahmedabad

Abstract

Nitrogen dioxide, NO₂, has strong absorption signatures in 436-448 nm region. Using this property, column density of this species has been determined at Ahmedabad, a low latitude station. Absorption spectrum has been measured by a ground-based spectroscopy technique during twilight period. Scattered zenith sunlight has been used as the source of light. The twilight slant column density (SCD) values have been found to be ~ 10¹⁷cm^–2. A summer maximum and a winter minimum, and a decreasing trend of NO₂ with an increase of solar activity level are seen. These results have been compared with the UARS and GOME satellite values.