International Journal of Innovative Research and Development

R. R. V. Suresh , K. V. K. R. K. Patnaik , U. S. Ramesh , S. C. Misra

Abstract

Wave rider buoy data during the period June 2009 to May 2010 was analyzed to examine the seasonal trends in the nearshore waves off Visakhapatnam, east coast of India. During fair weather conditions, wave heights were observed to be higher in the southwest monsoon season with maximum significant wave height (Hs) of about 2.76m in the month of July and average Hs of about 1.6m. The higher values of spectral band width emphasize that the wave heights covered a wide range for major period of the year. A large standard deviation of swell period represents the occurrence of distant swell in a wide range to the study region. The seasonal cycle of wave heights off Visakhapatnam, East Coast of India is dominated by SW monsoon winds. The waves at study area are resultant of sea and large swells from south of Bay of Bengal.

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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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