scholarly journals Observational Evidence of Summer Shamal Swells along the West Coast of India*

2013 ◽  
Vol 30 (2) ◽  
pp. 379-388 ◽  
Author(s):  
Johnson Glejin ◽  
V. Sanil Kumar ◽  
T. M. Balakrishnan Nair ◽  
Jai Singh ◽  
Prakash Mehra
Keyword(s):  
West Coast ◽  
Arabian Peninsula ◽  
Indian Subcontinent ◽  
Southwest Monsoon ◽  
Sea Waves ◽  
The West ◽  
Monsoon Period ◽  
West Coast Of India ◽  
Wind Sea ◽  
The Persian Gulf

Abstract Wave data collected off Ratnagiri, which is on the west coast of India, in 2010 and 2011 are used to examine the presence of the summer shamal swells. This study also aims to understand variations in wave characteristics and associated modifications in wind sea propagation at Ratnagiri. Wind data collected using an autonomous weather station (AWS), along with Advanced Scatterometer (ASCAT) and NCEP data, are used to identify the presence of summer shamal winds along the west coast of the Indian subcontinent and on the Arabian Peninsula. NCEP and ASCAT data indicate the presence of summer shamal winds over the Arabian Peninsula and northwesterly winds at Ratnagiri. This study identifies the presence of swells from the northwest that originate from the summer shamal winds in the Persian Gulf and that reach Ratnagiri during 30% of the summer shamal period. AWS data show the presence of northwest winds during May and southwest winds during the strong southwest monsoon period (June–August). Another important factor identified at Ratnagiri that is associated with the summer shamal events is the direction of wind sea waves. During the onset of the southwest monsoon (May), the sea direction is in the direction of swell propagation (northwest); however, during the southwest monsoon (June–August), a major part of the wind sea direction is from the southwest. The average occurrence of summer shamal swells is approximately 22% during the southwest monsoon period. An increase in wave height is observed during June and July at Ratnagiri due to the strong summer shamal event.

scholarly journals Co-existence of wind seas and swells along the west coast of India during non-monsoon season

Ocean Science ◽  
2013 ◽  
Vol 9 (2) ◽  
pp. 281-292 ◽  
Author(s):  
R. Rashmi ◽  
V. M. Aboobacker ◽  
P. Vethamony ◽  
M. P. John
Keyword(s):  
West Coast ◽  
Monsoon Season ◽  
Empirical Relation ◽  
The West ◽  
West Coast Of India ◽  
Wave Parameters ◽  
Wind Sea ◽  
Calm Weather ◽  
Sea Wind ◽  
Almost All

Abstract. An attempt has been made to understand the co-existence of wind seas and swells along the west coast of India during non-monsoon season. Wave data were collected in different years during non-monsoon season (off Goa during May 2005, off Ratnagiri during January–February 2008 and off Dwarka during December 2007–January 2008), which is fairly a calm weather season along these regions. Diurnal variation in wave parameters is noticeable along the central west coast of India (off Goa and Ratnagiri), which is due to the interaction of multidirectional waves (both wind seas and swells) of varying magnitudes and frequencies. Swells are predominantly mature (91%) and old (88%) during late pre-monsoon and post-monsoon seasons, respectively. Sea Swell Energy Ratio quantifies wind sea, swell and mixed seas prevailing in these regions during non-monsoon season. Intermodal distance (ID) between the energy peaks is moderately separated during non-monsoon season, whereas, during the shamal events, energy peaks are very close to each other (ID ∼ 0). However, pure wind seas (ID ∼ 1) are weakly present and found to co-exist with the swells almost all the time during non-monsoon season. Wind sea growth has been found while the swell propagates opposite to the direction of the wind and wind sea. Wind seas have minimum angular spreads in multimodal state. Under low winds, the interaction between wind sea and swell dominates and thereby the multimodal state reduces to unimodal state. The fetch available for the evolution of the wind sea spectrum has been estimated, and it is found to be less than 150 km. For the fetch limited condition, a non-dimensional empirical relation has been derived relating the significant wind sea height in terms of wind speed and peak wind sea period, and this relation fits for the west coast of India.

Colletteichthys occidentalis, a new Toadfish Species from the Arabian Peninsula and Northern Arabian Sea (Teleostei: Batrachoididae)

Zootaxa ◽  
2012 ◽  
Vol 3165 (1) ◽  
pp. 64 ◽  
Author(s):  
DAVID W. GREENFIELD
Keyword(s):  
West Coast ◽  
Arabian Sea ◽  
Arabian Peninsula ◽  
The Other ◽  
The West ◽  
West Coast Of India ◽  
Northern Arabian Sea

The second known species in the genus Colletteichthys is described from the Arabian Peninsula and the northern ArabianSea, supporting the validity of the genus Colletteichthys. Compared to the other known species, C. dussumieri from India,C. occidentalis has only a single tentacle above the eye whereas C. dussumieri has two or more. Colletteichtyhs dussumieri is restricted to the west coast of India.

scholarly journals Inter-annual variations in wave spectral characteristics at a location off the central west coast of India

2015 ◽  
Vol 33 (2) ◽  
pp. 159-167 ◽  
Author(s):  
V. Sanil Kumar ◽  
M. Anjali Nair
Keyword(s):  
West Coast ◽  
Spectral Characteristics ◽  
Wave Spectrum ◽  
Spectral Energy ◽  
Monsoon Period ◽  
West Coast Of India ◽  
Annual Variations ◽  
The Indian Ocean ◽  
Wind Sea ◽  
Two Peaks

Abstract. The inter-annual variations in wave spectrum are examined based on the wave data measured at 9 m water depth off the central west coast of India from 2009 to 2012 using a wave rider buoy. The temporal variation of the spectral energy density over a calendar year indicates similar variation in all the four years studied. The inter-annual variations in wave spectrum are observed in all months with larger variations during January to February, May and October to November due to the changes in wind-sea. The seasonal average wave spectrum during the monsoon (June–September) is single-peaked and the swell component is high in 2011 compared to other years. The annual averaged wave spectrum had higher peak energy during 2011 due to the higher spectral energy present during the monsoon period. During the non-monsoon period, two peaks are predominantly observed in the wave spectra; with the average peak at 0.07 Hz corresponding to the swells from the Indian Ocean and another at 0.17 Hz due to the local wind field.

Hydrography and circulation off the west coast of India during the Southwest Monsoon 1987

1990 ◽  
Vol 48 (2) ◽  
pp. 359-378 ◽  
Author(s):  
S. R. Shetye ◽  
A. D. Gouveia ◽  
S. S. C. Shenoi ◽  
D. Sundar ◽  
G. S. Michael ◽  
...  
Keyword(s):  
West Coast ◽  
Southwest Monsoon ◽  
The West ◽  
West Coast Of India

Nearshore Currents along the Karnataka Coast, West Coast of India

2012 ◽  
Vol 3 (1) ◽  
pp. 71-84 ◽  
Author(s):  
V. Sanil Kumar ◽  
G. Udhaba Dora ◽  
C. Sajiv Philip ◽  
P. Pednekar ◽  
Jai Singh
Keyword(s):  
West Coast ◽  
Current Data ◽  
Surface Currents ◽  
The West ◽  
Monsoon Period ◽  
Near Surface ◽  
West Coast Of India ◽  
Average Value ◽  
Alongshore Current ◽  
Alongshore Wind

Measured current data at 7 locations and tide data at 3 locations during the pre-summer monsoon period along the west coast of India is used in the study. The surface currents during March showed a predominant northward trend and during April it was towards south. Estimated tidal currents were upto 25 cm s−1 with an average value of 8 cm s−1. Current tidal form number varied from 0.56 to 1 at different locations indicating currents are mixed. M2 and S2 tidal current constituents rotated clock wise at all location. Near surface, the alongshore current was 2.6 to 5.9% of the alongshore wind and near bottom it was 1.9 to 3.6% of the alongshore wind.

A ‘Persian Gulf’ Seal from Lothal

Antiquity ◽  
1963 ◽  
Vol 37 (146) ◽  
pp. 96-99 ◽  
Author(s):  
S. R. Rao
Keyword(s):  
West Coast ◽  
Persian Gulf ◽  
The Other ◽  
Indus Civilization ◽  
The West ◽  
West Coast Of India ◽  
Other Hand ◽  
Gulf Islands ◽  
Trade Route ◽  
The Persian Gulf

Lothal is an important harbour-town of the Indus Civilization at the head of the Gulf of Cambay on the west coast of India (FIG. 1). During the recent excavations there, a circular steatite seal has been found which is neither wholly Indian nor Sumerian in workmanship (PL. IX). On the other hand, it closely resembles the seals from the Persian Gulf islands found by the Danish expedition led by Professor Glob and Dr Bibby. Sir Mortimer Wheeler has named them 'Persian Gulf' seals which, according to him, 'appear to have been made at the various entrepôts (such as Bahrain itself) of a cosmopolitan Persian Gulf trade of the kind which has been analyzed by A. L. Oppenheim from Larsa tablets' (note I). Commenting on these seals, the late Col. D. H. Gordon wrote: 'The problem of Bahrain is a very interesting and important one, and it is possible that these seals may help to solve it. Some day such seals may come to light in India, but so far they have not; Bahrain may have been Dilmun and it was almost certainly an entrepôt on the trade route to India, and so it is possible that seals of this kind were carried on to the Indus or to ports in Kathiawad and will some day be found in those localities, though this will not necessarily make them Indian or even of Indian style' (note 2). The hope expressed by Gordon has now been fulfilled by the discovery of a 'Persian Gulf' seal at Lothal, thus providing the first real evidence of trade contacts between India and the Persian Gulf.

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