Browsing by Author "Patnaik, K. V. K. R. K."

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A study on the seasonal variability of nearshore waves off Visakhapatnam, east coast of India
(International Journal of Innovative Research and Development, 2012-12) Suresh, R. R. V.; Patnaik, K. V. K. R. K.; Ramesh, U. S.; Misra, S. C.
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
Acoustic estimation of suspended sediment concentration from turbidity in the nearshore areas off Visakhapatnam
(INCHOE2014 (Proceedings), 2012-02-05) Patnaik, K. V. K. R. K.; Suresh, R. R. V.
Patnaik, KVKRK., Suresh, RRV., 2014. Acoustic estimation of suspended sediment concentration from turbidity in the nearshore areas off Visakhapatnam, Proceedings of the Fifth Indian National Conference on Harbour and Ocean Engineering (INCHOE2014), 5-7 Feb. 2014, CSIR-NIO, Goa, India. Accurate estimation and monitoring of suspended sediment concentration in the nearshore areas is a challenging task involved in the maintenance of draft of navigational channels, ports and harbors. In the nearshore environment Suspended Sediment Concentration varies significantly both in time and space in response to various forcing mechanisms. Though estimation of this through Acoustic remote sensing is a surrogate method, it is proved to be a best method. The present study is based on the simultaneous data obtained from 600 Khz workhorse ADCP, Turbidity sensor and LISST portable. ADCP was side mounted to BTV Sagar Manjusha at a depth region of 20m and programmed to record the data for every one minute for the period of 3 days to cover six tidal cycles. These data are used to develop a location specific version of the sonar equation which converts the ADCP echo intensity to turbidity (NTU). This equation was obtained by relating echo intensity and turbidity. It is also found that the particle size in the study area ranging from 50 – 400 μm. It is also found that the estimated turbidity is in good agreement with the measured turbidity values.
Analysis and design of berthing structure for handling bulk cargo
(Indian Maritime University, Visakhapatnam, 2019) Gaikwad, Amar G.; Patnaik, K. V. K. R. K.; Nagesh, Bh.
This paper presents basic ideas and terminology of structural optimization of a berthing structure which was analysed and designed using different load conditions and the best possible way to construct a new berthing structure. All the suitable and useful data was adopted from the proposed site location at Belekeri port in Karnataka state and studied carefully before designing the structure. The berth is to be designed for a vessel having capacity of 120000DWT. The structure is subjected to various forces and combinations such as, High tide, Earthquake, High winds, heavy live loads as per IS: 4651-1983.The proposed berthing structure Model was generated with suitable geometry using STAAD-Pro software, after which all considerable loads on the structure were induced and analysed carefully. Different sectional dimensions were trialed during the analysis and the most acceptable structure was designed with providing all structural members with suitable reinforcement and satisfying all marine safety conditions. This research is an attempt to understand the concept of design and analysis of berthing structures under different conditions of loading.
Assessment of coringa mangrove shoreline migration using geospatial techniques
(Journal of Operational Oceanography, 2020-11-06) Sharma, Garima.; Patnaik, K. V. K. R. K.
Coringa Mangroves in the Kakinada Bay have evolved as the second-largest mangroves in the East Coast of India over the last century. The Coringa Mangrove shoreline has accreted considerably in the past decades as observed from the satellite imageries, adding value to the natural biodiversity of flora and fauna. This study is focused on quantifying the long term changes of Coringa mangrove shoreline using the Landsat imageries for years 1977, 1988, 2000, and 2013 using the Digital Shoreline Analysis System. For a mangrove shoreline length of 20.5 km, 41 transects were cast at an interval of 500 m for calculating the change and their migration distance using three statistical methods, namely End Point Rate (EPR), Net Shoreline Movement (NSM) and Linear Regression Rate (LRR). Results showed that there was considerable growth of mangroves in the bay leading to the seaward migration of the mangrove shoreline from the year 1977– 2013. The study observed the difference in the mangrove shoreline migration dynamics in the South-eastern (near the bottom of the spit) and the western part of the Kakinada Bay. The calculated average degradation rate due to erosion is −5.19 m.yr−1 and the average accretion rate leading to their growth is 14.83 m.yr−1 for all transects of the 20.5 km mangrove shoreline stretch during this period. The results hold importance as they help in identifying the regions prone to mangrove degradation and enable management planning for the protection of the eroding stretch of the mangrove shoreline.
Assessment of Coringa Mangrove shoreline migration using geospatial techniques
(Taylor and Francis, 2022-05-04) Sharma, G.; Patnaik, K. V. K. R. K.
Coringa Mangroves in the Kakinada Bay have evolved as the second-largest mangroves in the East Coast of India over the last century. The Coringa Mangrove shoreline has accreted considerably in the past decades as observed from the satellite imageries, adding value to the natural biodiversity of flora and fauna. This study is focused on quantifying the long term changes of Coringa mangrove shoreline using the Landsat imageries for years 1977, 1988, 2000, and 2013 using the Digital Shoreline Analysis System. For a mangrove shoreline length of 20.5 km, 41 transects were cast at an interval of 500 m for calculating the change and their migration distance using three statistical methods, namely End Point Rate (EPR), Net Shoreline Movement (NSM) and Linear Regression Rate (LRR). Results showed that there was considerable growth of mangroves in the bay leading to the seaward migration of the mangrove shoreline from the year 1977–2013. The study observed the difference in the mangrove shoreline migration dynamics in the South-eastern (near the bottom of the spit) and the western part of the Kakinada Bay. The calculated average degradation rate due to erosion is −5.19 m.yr−1 and the average accretion rate leading to their growth is 14.83 m.yr−1 for all transects of the 20.5 km mangrove shoreline stretch during this period. The results hold importance as they help in identifying the regions prone to mangrove degradation and enable management planning for the protection of the eroding stretch of the mangrove shoreline.
Biophysical responses to tropical cyclone Hudhud over the Bay of Bengal
(Taylor & Francis, 2021-07-03) Maneesha, K.; Prasad, D. H.; Patnaik, K. V. K. R. K.
Cyclone Hudhud originated in the Andaman Sea on 6 October 2014. Later, it intensified into a cyclonic storm on 8 October and eventually made landfall at Visakhapatnam on 12 October as a very severe cyclonic storm. It was intensified off of Visakhapatnam by high stratified waters with a thick barrier layer that held significant heat content. In this study, we analysed the data along the cyclone track using a combination of satellite, in-situ Argo and Bio-Argo data to assess the upper oceanic changes along the Hudhud track. Notable changes were detected in the upper ocean due to its extreme intensification and prior passage through cold-core eddies. A high translation speed and persistent stratification dominated the effects caused by the cold-core eddies on the intensification of the cyclone and the same was attributed to the upwelled subsurface chlorophyll maxima. The biophysical changes in the top 150 m layer derived from Argo floats were in good agreement with the satellite and model data. Further, it was observed that the increase in lightning flash rates also influenced surface productivity during the cyclone. Subsequent to the passage of the cyclone, the ocean took two weeks to achieve its original state.
Biophysical responses to tropical cyclone Hudhud over the Bay of Bengal /
(Taylor & Francis, 2019-11-04) Patnaik, K. V. K. R. K.
Cyclone Hudhud originated in the Andaman Sea on 6 October 2014. Later, it intensified into a cyclonic storm on 8 October and eventually made landfall at Visakhapatnam on 12 October as a very severe cyclonic storm. It was intensified off of Visakhapatnam by high stratified waters with a thick barrier layer that held significant heat content. In this study, we analysed the data along the cyclone track using a combination of satellite, in-situ Argo and Bio-Argo data to assess the upper oceanic changes along the Hudhud track. Notable changes were detected in the upper ocean due to its extreme intensification and prior passage through cold-core eddies. A high translation speed and persistent stratification dominated the effects caused by the cold-core eddies on the intensification of the cyclone and the same was attributed to the upwelled subsurface chlorophyll maxima. The biophysical changes in the top 150 m layer derived from Argo floats were in good agreement with the satellite and model data. Further, it was observed that the increase in lightning flash rates also influenced surface productivity during the cyclone. Subsequent to the passage of the cyclone, the ocean took two weeks to achieve its original state.
Contribution of tides to sea level variations along Visakhapatnam, India
(Taylor & Francis, 2010-08-07) Prasad, K. V. S. R.; Sreenivas, P.; Patnaik, K. V. K. R. K.
The sea level variations along Visakhapatnam coast are governed by astronomical tides and nontidal oscillations including atmospheric pressure, winds, coastal currents, Ekman Pumping, and river influx. Tidal and nontidal sea level oscillations are usually studied separately because of the vastly different ways in which they are forced. In this study the tidal oscillations along Visakhapatnam are analyzed using GOTIC2 tidal model. The correlation between monthly mean sea level and monthly mean tides is 47% (r = 0.68) and increases to 54% (r = 0.74) when applied for inverse-barometric effect. The major six partial tides are computed and presented. The tidal variations from Neap tide to Spring tide are studied.
East India coastal current induced eddies and their interaction with tropical storms over Bay of Bengal
(Taylor & Francis, 2014-02-01) Patnaik, K. V. K. R. K.; Maneesha, K.; Sadhuram, Y.; Prasad, K. V. S. R.; Ramana Murty, T. V.; Brahmananda Rao, V.
Eddies of about 10 to 500km in diameter, persisting for periods of days to months are commonly referred to as mesoscale eddies in oceanography. Energetic eddies are frequently found in the vicinity of faster flowing currents like the Gulf Stream and the Kuroshio. The present study deals with the role of eddies, occurring in the vicinity of the East India Coastal Current (EICC), particularly in the months of April to May and October to November, during the intensification of tropical cyclones in the Bay of Bengal. Although the Bay of Bengal is well known for mesoscale eddies, the role of these in the intensification/weakening of the storms is quantitatively unknown. In this study, an attempt has been made to conduct a quantitative analysis of the role of these eddies (warm/cold) in the intensification of the storms over the Bay of Bengal. It is found that in the case of a severe cyclone occurring over the period of 16 to 19 October, 1999 the intensity of the storm was enhanced by 260% due to its interaction with a warm eddy. This is much higher than that reported in case of, for example, Hurricane Opal (119%) and Typhoon Maemi (138%). The enthalpy fluxes (latent plus sensible) are much higher (lower) over warm (cold) eddies. The warm eddy opposes the cooling induced by the storm and helps the intensification through the supply of large amount of enthalpy flux. This emphasizes the importance of eddies in the intensification of storms over the Bay of Bengal, which is omitted by meteorologists in forecasting the intensification of storms.
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.
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.
Long term morphodynamic evolution of Kakinada bay using upscaling methods
(Marine Engineers Review (India), 2020) Sharma, Garima.; Sivakholundu, K. M.; Patnaik, K. V. K. R. K.
Kakinada Bay has evolved over the last century dynamically by the action of wind, waves, tides and currents. Formation of Hope Island and development of Coringa Mangroves are attributed to the hydrodynamic 'forcings' and sediment dynamics. This study aims to predict the future morphological development of Kakinada Bay for next 100 years. The morphological model was built up in the DELFT 3D package. Model setting parameters were fixed after analysing their effect on the simulation results. For reducing the computational time and effort for simulating long term morphological development, upscaling methods such as morphological acceleration factor (MORFAC) and morphological tide were incorporated in the morphological model. Morphological tide was formed using tidal constituents - M2, O1 and K1. The MORFAC value for this study was chosen as 30 after undergoing the sensitivity test analysis using Brier Score Skill (BSS) Score. The model was run for 19 years for hindcasting and 100 years for forecasting. In order to establish confidence in the model, it was calibrated and validated using hindcast modelling. The hindcast simulation results were used to match the simulated shoreline with satellite observed shoreline from year 1988 to 2000, and 2006 to 2013 and the results were in good agreement. It was observed that the south-western part of the bay has accreted more rapidly while south-eastern part of the bay has undergone slight erosion. Thereafter long term morphological model was run for 100 years to predict the future evolution of bay. Results of these simulations show the capability of the long term morphological model to predict the spatial and temporal geo-morphological changes.
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.
On the relation of vegetation and southwest monsoon rainfall over Western Ghats, India
(Springer Link, 2016-10) Lakshmi Kumar, T. V.; Uma, R.; Koteswara Rao, K.; Barbosa, H.; Patnaik, K. V. K. R. K.; Prabha Jothi, E.
This article presents the tendency of the normalized difference vegetation index (NDVI) and the dependence of vegetation on the rainfall and number of rainy and non-rainy days over Western Ghats. The study makes use of MODIS Terra NDVI data with 8-day intervals and 250-m resolution from 2000 to 2010 during the southwest monsoon (June to September) season. The results show an increasing tendency of the NDVI over different test sites in Western Ghats. The relation of the NDVI with the Antecedent Precipitation Index obtained from rainfall showed good agreement, and the relation of rainfall and the NDVI was mainly dependent on the available soil moisture levels and elevations of the test sites. Correlations were significant and positive with the number of rainy days and negative with the number of non-rainy days with a nearly 2-month lag.
On the relation of vegetation and southwest monsoon rainfall over Western Ghats, India /
(Springer Nature, 2016-07-05) Patnaik, K. V. K. R. K.
This article presents the tendency of the normalized difference vegetation index (NDVI) and the dependence of vegetation on the rainfall and number of rainy and non-rainy days over Western Ghats. The study makes use of MODIS Terra NDVI data with 8-day intervals and 250-m resolution from 2000 to 2010 during the southwest monsoon (June to September) season. The results show an increasing tendency of the NDVI over different test sites in Western Ghats. The relation of the NDVI with the Antecedent Precipitation Index obtained from rainfall showed good agreement, and the relation of rainfall and the NDVI was mainly dependent on the available soil moisture levels and elevations of the test sites. Correlations were significant and positive with the number of rainy days and negative with the number of non-rainy days with a nearly 2-month lag.
Planning and feasibility study of LNG terminal for visakhapatnam port trust
(Twenty Seventh National Convention of Marine Engineers, 2013-08) Chandrasekhar, B.; Patnaik, K. V. K. R. K.
To meet India’s growing energy demands, it is proposed to establish a LNG terminal at east coast for Visakhapatnam port trust. Its location is found to be feasible near the newly proposed Satellite Port and at proposed fishing harbour at Mullakuddu, Bheemunipatnam. This work comprises of the preliminary study and feasibility report along with plant process and basic requirements for setting up of LNG terminal for handling, storage and evacuation at Bheemunipatnam for Visakhapatnam Port Trust. The proposed LNG terminal facility at Bheemunipatnam is planned with the following infrastructural facilities for the smooth handling of LNG, which consists of a Jetty, LNG Tanks, Vaporisation plant, Fire control mechanism, Maintenance workshops, Administration Building, Guard houses, Utility area & Control rooms. As the first phase, the planned LNG terminal capacity is 2mmtpa with two LNG storage tanks of 85,000 m3 capacity, with a provision to increase it to 5mmtpa in future.
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.
Study on the wave diffraction patterns in the Kakinada bay
(Indian Maritime University, Visakhapatnam, 2019) Sharma, Garima.; Patnaik, K. V. K. R. K.
Kakinada is one of the major upcoming ports of India and holds great importance for shipping activities. This region is said to be low-lying area and highly susceptible to erosion. To protect the port from action of waves, tides and strong currents, breakwater was constructed at the entrance of the channel. Current study makes an attempt to understand how wave energy gets reduced and wave diffraction occurs due to presence of the breakwater. Numerical solution of the mild slope equation and diffraction pattern are studied using MIKE 21 PMS model. Intense wave activity is higher during south west monsoon season than north east monsoon season. Significant wave heights have reduced considerably to 0-0.15m because of the breakwater during both the seasons and no waves are entering inside the bay. Waves have bent at the breakwater due to diffraction along with the formation of concentric ripples with the decreased wave heights.
Study on the wave diffraction patterns in the Kakinada bay
(Journal of offshore structure and technology, 2020) Sharma, Garima.; Patnaik, K. V. K. R. K.
Kakinada is one of the major upcoming ports of India and holds great importance for shipping activities. This region is said to be low-lying area and highly susceptible to erosion. To protect the port from action of waves, tides and strong currents, breakwater was constructed at the entrance of the channel. Current study makes an attempt to understand how wave energy gets reduced and wave diffraction occurs due to presence of the breakwater. Numerical solution of the mild slope equation and diffraction pattern are studied using MIKE 21 PMS model. Intense wave activity is higher during south west monsoon season than north east monsoon season. Significant wave heights have reduced considerably to 0–0.15 m because of the breakwater during both the seasons and no waves are entering inside the bay. Waves have bent at the breakwater due to diffraction along with the formation of concentric ripples with the decreased wave heights.
The intrusion of spicy water favours the intensification of Arabian Sea cyclones
(Taylor & Francis, 2023-03-15) Maneesha, K.; Brahmananda Rao, V.; Patnaik, K. V. K. R. K.; Franchito, S. H.
The intensity of the cyclones in the Arabian Sea has been increasing in recent years. Approximately ten storms were intensified into severe cyclones over spicy waters of the northern Arabian Sea during 1998-2019. Reduction in upwelling was observed due to decreasing wind speed, which raised the sea surface temperature (SST) and the intrusion of spicy waters from the Red Sea and the Persian Gulf acted as a barrier to mixing in the top layers, especially in May. Consequently, there was a noticeable increase in the heat content of the 50 m surface layer. This research presents two main rationales that explain the intensification of these cyclones. The first rationale explores the increasing trends in SST and ocean internal energy, while the second investigates the influence of the intrusion of spicy Persian Gulf waters into the Oman coast. The results showed that spicy water from the north suppressed the upwelling in the cold core eddy off the Oman coast and that higher SSTs and high latent heat flux almost double the climatological values off the Oman coast in May.