Observations and numerical simulation of the sea and land breeze circulations along the west coast of India

Abstract

Sea breeze circulation along the west coast of India during the Indian Ocean Experiment (1999) is investigated. Pilot balloon sounding data from Mumbai, Goa, and Trivandrum, India show a diurnal variation in wind direction caused by land and sea breeze circulations along the west coast of India. Rawinsonde wind profiles taken from R/V Sagar Kanya 130 km offshore from the west coast of India show the presence of sea and land breeze circulations. Infrared satellite images show the furthest extent of the sea breeze circulation over the Arabian Sea to be around 200 km. Constant level balloons released from Goa, India also showed the extent of the sea breeze over the ocean to be 200 km. A mesoscale numerical model was used to further investigate the sea breeze circulation and its horizontal extent over the ocean. Simulated cross sections along the west coast of India show the horizontal extent of the afternoon sea breeze over the ocean to vary from around 130 to 260 km. Vertical velocities of about 0.25 ms⁻¹ were simulated inland as the sea breeze interacted with the mountains along India’s west coast.