Estimation of Water Vapor Attenuation Variations at Microwave Frequencies over Kolkata, India

摘要

The radiosonde data available from British Atmospheric Data Centre (BADC) over Kolkata, India (22.65oN) for two different season (winter season and rainy season) were analyzed to observe the variation of Water vapor attenuation in the frequency range 10 GHz -30 GHz. Zenith antenna temperatures at 10, 20, 22.235, 23.834, 26, 26.5 and 30 GHz have been determined for the different value of water vapor content during January-February and July-August. Antenna temperature, as expected, is less at 10 GHz, but increases with increase in frequency, thereafter, becoming maximum at the water vapor resonance line of 22.235 GHz, and then decreasing with further increase in frequency. The attenuatio n values in terms of dB have also been evaluated over this place