Spatio-Temporal Distribution and Variability of High Threshold Wind Speed and Significant Wave Height for the Indian Ocean

2020 ◽  
Vol 177 (9) ◽  
pp. 4559-4575 ◽  
Author(s):  
S. Sreelakshmi ◽  
Prasad K. Bhaskaran
2015 ◽  
Vol 44 (2) ◽  
pp. 225-231 ◽  
Author(s):  
Chiranjivi Jayaram ◽  
Saurabh Bansal ◽  
A. Sai Krishnaveni ◽  
Neethu Chacko ◽  
V. M. Chowdary ◽  
...  

2015 ◽  
Vol 32 (11) ◽  
pp. 2211-2222 ◽  
Author(s):  
R. Harikumar ◽  
N. K. Hithin ◽  
T. M. Balakrishnan Nair ◽  
P. Sirisha ◽  
B. Krishna Prasad ◽  
...  

AbstractOcean state forecast (OSF) along ship routes (OAS) is an advisory service of the Indian National Centre for Ocean Information Services (INCOIS) of the Earth System Science Organization (ESSO) that helps mariners to ensure safe navigation in the Indian Ocean in all seasons as well as in extreme conditions. As there are many users who solely depend on this service for their decision making, it is very important to ensure the reliability and accuracy of the service using the available in situ and satellite observations. This study evaluates the significant wave height (Hs) along the ship track in the Indian Ocean using the ship-mounted wave height meter (SWHM) on board the Oceanographic Research Vessel Sagar Nidhi, and the Cryosat-2 and Jason altimeters. Reliability of the SWHM is confirmed by comparing with collocated buoy and altimeter observations. The comparison along the ship routes using the SWHM shows very good agreement (correlation coefficient > 0.80) in all three oceanic regimes, [the tropical northern Indian Ocean (TNIO), the tropical southern Indian Ocean (TSIO), and extratropical southern Indian Ocean (ETSI)] with respect to the forecasts with a lead time of 48 h. However, the analysis shows ~10% overestimation of forecasted significant wave height in the low wave heights, especially in the TNIO. The forecast is found very reliable and accurate for the three regions during June–September with a higher correlation coefficient (average = 0.88) and a lower scatter index (average = 15%). During other months, overestimation (bias) of lower Hs is visible in the TNIO.


Previous studies investigated the Indian Ocean's currents' impacts on the trajectory movement of MH370 debris. This chapter introduces the novel approach of investigating the wave pattern variations in the Indian Ocean on the MH370 debris. The novel approach based on the altimeter interferometry technique is utilized in this chapter. To this end, dual SIRAL instruments on-board of CryoSat-2 are applied to obtain the annual cycle of significant wave height across the Indian Ocean. In this chapter, in a one-year significant wave height cycle, the swell remains propagating from the Southwest to the Northeast from January to March 2015 with a maximum significant wave height of 5 m in the Northeast Offshore Australian Shelf and 7 m significant wave height Southwest of Australian Shelf. In this circumstance, the Pareto algorithm proves that the flaperon would submerge to a water depth less than 300 m on account of the impact of wave power of 22000 KJ/m/wave. It can be said that the flaperon would be submerged further to a water depth of 1000 m because of the wave power of 30000 KJ/m/wave.


2015 ◽  
Vol 6 (4) ◽  
pp. 286-294 ◽  
Author(s):  
Aditya Chaudhary ◽  
Sujit Basu ◽  
Raj Kumar ◽  
K.V.S.R. Prasad ◽  
Rashmi Sharma

2008 ◽  
Vol 38 (7) ◽  
pp. 1597-1606 ◽  
Author(s):  
T. Lamont-Smith ◽  
T. Waseda

Abstract Wave wire data from the large wind wave tank of the Ocean Engineering Laboratory at the University of California, Santa Barbara, are analyzed, and comparisons are made with published data collected in four other wave tanks. The behavior of wind waves at various fetches (7–80 m) is very similar to the behavior observed in the other tanks. When the nondimensional frequency F* or nondimensional significant wave height H* is plotted against nondimensional fetch x*, a large scatter in the data points is found. Multivariate regression to the dimensional parameters shows that significant wave height Hsig is a function of U2x and frequency F is a function of U1.25x, where U is the wind speed and x is the horizontal distance, with the result that in general for wind waves at a particular fetch in a wave tank, approximately speaking, the wave frequency is inversely proportional to the square root of the wind speed and the wavelength is proportional to the wind speed. Similarly, the wave height is proportional to U1.5 and the orbital velocity is proportional to U. Comparison with field data indicates a transition from this fetch law to the conventional one [the Joint North Sea Wave Project (JONSWAP)] for longer fetch. Despite differences in the fetch relationship for the wave tank and the field data, the wave height and wave period satisfy Toba’s 3/2 power law. This law imposes a strong constraint on the evolution of wind wave energy and frequency; consequently, the energy and momentum retention rate are not independent. Both retention rates grow with wind speed and fetch at the short fetches present in the wave tank. The observed retention rates are completely different from those typically observed in the field, but the same constraint (Toba’s 3/2 law) holds true.


Sign in / Sign up

Export Citation Format

Share Document