Numerical simulation of sea breeze characteristics observed at tropical coastal site, Kalpakkam

Sea breeze characteristics around Kalpakkam tropical coastal site are studied using an Advanced Regional Prediction System (ARPS) mesoscale model, which is non-hydrostatic, compressible atmospheric prediction model following the terrain coordinate system. Various options such as surface physics, atmospheric radiation physics, Coriolis force, microphysics, cumulus parameterization and 1.5 level TKE closure scheme for diffusion are included in the model. A joint meteorological field experiment was carried out by IITM-Pune and IGCAR at Kalpakkam by deploying state-of-the-art sensors and tether balloon systems for observing the height profiles of meteorological parameters. The data obtained from the field experiment are used here to compare the results from numerical simulations. From the simulated results, it is seen that duration of the sea breeze is 6 hours which agrees well with the observations. The height of the Thermal Internal Boundary Layer (TIBL) is also simulated from the vertical profiles of potential temperature. Simulated wind speed and wind directions are compared with the 50 m tower data and potential temperature profiles are compared with the kytoon data. Results are in good agreement with the observed values except during night time wherein a small difference is seen in the wind speed. © Printed in India.