Journal Articles
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Item Intra-annual studies of mixed layer depth in the Arabian Sea using a 3 ½ layer Indian ocean model(Bentham Open, 2009-09-04) Patnaik, K. V. K. R. K.; Sreenivas, P.; Venkata Ramu, Ch.; Arun Kumar, S. V. V.; Prasad, K. V. S. R.Mixed layer is the upper layer of the ocean, where significant physical, chemical and biological activities take place. Knowledge of mixed layer depth variability is important in the studies of air-sea interaction, acoustic propagation, heat transport and fisheries. The Arabian Sea experiences extremes in atmospheric forcing that lead to intra-annual and inter-annual variability. Since the climatic conditions over the Arabian Sea are highly variable, the mixed layer depth also changes seasonally. Hence the intra-annual variability of mixed layer depth in the Arabian Sea has been examined using 3 ½ layer Indian Ocean model. The model is integrated for 8 years (1993–2000) with annually varying monthly averaged winds derived from ERS-2 scatterometer. In addition to this data, inter annually varying monthly averaged satellite estimates of precipitation from Global Precipitation Climatology were also incorporated in the model. Model results show a steady deepening of mixed layer depth in the central Arabian Sea during southwest monsoon period. The model shows its capability to predict the shallow mixed layer depths caused by coastal upwelling off Somalia during southwest monsoon period and is able to capture the Lakshadweep high/low as it predicted successfully the deeper/shallow mixed layer observed during these periods.Item Role of nearshore waves in identifying vulnerable zones during storm and normal events(Enviroscan, 2010) Arun Kumar, S. V. V.; Prasad, K. V. S. R.; Patnaik, K. V. K. R. K.; Venkata Ramu, Ch.; Sreenivas, P.During the SW Monsoon season, the average nearshore wave energy 3 along the coast is higher for the stations 3 and 20 with values 4.3 x10 2 J/m (Fig. 2). From the southern end of the coast, the wave energy is 3 2 decreasing having a least value of 2.2 x10 J/m in the Lawson's Bay (station 13). Hence, during this season, RK Beach, Jodugullapalem Beach and Sagar nagar Beach are the high energetic zones and so there is a possibility of erosion at these places.Item Hydrodynamic variability along the outlet channel of Kolleru lake, India(Proquest, 2011-04) Prasad, K. V. S. R.; Apparao, A. P. V.; Arun Kumar, S. V. V.; Patnaik, K. V. K. R. K.; Venkata Ramu, Ch.Hydrodynamic parameters like Salinity intrusion, circulation and mixing properties, flushing characteristics, Total salt etc., along outlet channel of Kolleru Lake have been studied during May 2010-April 2011. The observations reveal that the channel had lost 94.2% of Total Salt during May-November 2010 and regained upto 94.0% by April 2011. Flushing time has been varied from 1.81 to 5.61 tidal cycles. The Diffusion Coefficient (Kx) varied randomly between 0.0032 x 105 and 5.6 x 105 m2/s during July-August 2010. The yearly mean Kx ranges between 0.0095 x 105 and 2.1 x 105 m2/s. The seasonal variation of depth mean salinity along the axis of the channel shows a wide range. During periods of very high discharge, salt wedge has been formed near the confluence and extended few kilometers upstream. For moderate discharge, the channel has become partially mixed with a high degree of stratification.Item Observational analysis on the run-up height and inundation along the Andhra coast during December 26, 2004 Indian Ocean tsunami(Elsevier, 2012-02-02) Patnaik, K. V. K. R. K.; Arun Kumar, S. V. V.; Venkata Ramu, Ch.; Prasad, K. V. S. R.The 26 December 2004 earthquake with magnitude of 9.3 triggered one of the most destructive tsunamis in the Indian Ocean and caused widespread inundation and extensive damage in terms of life and property along the coasts of several Asian countries. In India, the Andaman and Nicobar group of Islands, the coastal states of Tamil Nadu, Andhra Pradesh and Kerala were severely affected. Post tsunami field surveys were conducted along the Andhra coast (central part of east coast of India) to assess the tsunami run-up heights and inundation. Estimation of tsunami run-up heights and inundation relative to the mean sea level were made based on the water marks on permanent structures and marks of debris on trees. Observations revealed that the Andhra coast was largely affected by the tsunami and in general the intensity of the tsunami along the Andhra coast decreased from south to north. Maximum run-up heights of 4.5 m were observed in the southern parts and minimum run-up heights of 2 m were observed in the northern parts of the Andhra coast. While, the distance of inundation varied from 60 to 900 m along the coast. The interdependency between the tsunami run-up height and inundation with the physical setup of the shoreline has been identified. Also local features such as dunes, vegetation and steepness of beaches played vital role in reducing the impact of tsunami. Dependency of tsunami parameters on Coastal Characteristic Index (CCI) was attempted for the first time for the Indian coast. Good correlation has been observed between run-up heights, inundation and CCI. The width of the continental shelf also played a crucial role in causing damage to the coast.