International Journal of Innovative Research and Development

K. V. S. R. Prasad , P. S. N. Acharyulu , P. J. V. Ramakrishna

Abstract

Extreme weather events like cyclones cause severe damage to coasts by inducing very high waves. Studies of such waves are important for several coastal processes. Satellite altimetry data used to study one of such extreme events LAILA cyclone during the year 2010 over Bay of Bengal. This cyclone caused severe erosion along the coast and of course first ever severe cyclone crossed Andhra coast since may- 1990. The satellite altimetry data showed that prolonged high waves during and after the cyclone. The in-situ observations show wave heights up to 3m under the influence of cyclone. The satellite altimetry gridded data performs well with In-situ data. Keywords: Coastal processes, Erosion, Extreme events, Satellite altimetry, Wave heights

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Venkata Ramu , K. V. K. R. K. Patnaik , K. V. S. R. Prasad , S. V. V. Arun Kumar , P. S. N. Acharyulu

Abstract

The upper ocean is dramatically affected during tropical cyclones (TCs). Cyclones interact not only with the surface but also with the deeper oceans, the depth depending upon the strength of the wind mixing. Hence, it is necessary to consider the thermal structure of the upper ocean for cyclone studies. Rapid intensification of cyclone Nargis in the Bay of Bengal from category-1 to category-4 within 24 hours was attributed to the presence of a pre-existing warm SSHA evidenced by the insitu (Argo data) and altimeter observations. The warmer layers of 26°C extended up to 100 m beneath the surface such as Isothermal layer depth (ILD) and barrier layer thickness (BLT) and Upper Ocean Heat Content (UOHC) during the cyclone progression were computed. The rate of intensification and final intensity of cyclones are sensitive to the initial spatial distribution of the mixed layer. The most apparent effect of TC passage is noted by the marked SST cooling, and the response of the ocean mixed layer temperature typically 1 to 6°C towards the right of the storm track. In the present work, the response of Upper Ocean to the tropical cyclones over Bay of Bengal based on the satellite Altimetry, ARGO, RAMA buoys and QUICKSCAT forced (MOM-GODAS) data. The present studies suggest the use of sea surface height anomalies (SSHA) data derivable from satellite altimeters are more useful instead of sea surface temperatures in the atmospheric models, particularly, in the cyclone and coupled models.

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