Study of sea breeze and land breeze along the west coast of Indian sub-continent over the latitude range 15 degrees N to 8 degrees N during INDOEX IFP-99 (SK-141) cruise

Sea breeze and land breeze are the most interesting mesoscale phenomena obs erved in the coastal regions. We report here the results of a study conduct ed to determine the horizontal extent of sea and land breeze circulation in the Arabian Sea during the INDOEX IFP-99 (SK-141) cruise. As a part of IND OEX IFP-99 (SK-141) cruise, the meteorological data over the ocean surface were collected over a latitude range 15 degreesN to 20 degreesS by mounting the sensors on a 7-m long retractable boom onboard the ship, nearly 10 m a bove the sea surface. Observations made during 21-24 January 1999 (forward leg: latitude 15 degreesN to 8 degreesN; longitude 72.3 degreesE to 76.4 de greesE) when the ship was close to the west coast of India and 5-10 March 1 999 (return leg: latitude 15 degreesN to 10 degreesN; longitude 71.9 degree sE to 74.8 degreesE) when the ship was further away from the coast were use d for the study of the extent of sea/land breeze over the Arabian Sea. Simu ltaneous observations were made by 30-m meteorological tower located at Thi ru-vananthapuram, 500 m away from the Arabian Sea coast, and the data have been used to compare the existence of sea/land breeze circulations. During the forward leg of the cruise, when the ship was closer to the west coast o f India, the time series of wind direction show prominent wind reversal, si milar to those observed at Thiruvananthapuram during the same period. But d uring the return leg, when the ship was away from the coast, the wind direc tion reversal was absent onboard ship, thereby showing the horizontal exten t of the land/sea breeze at the west coast of India.