On a new Bathypelagic fish,Holanthias perumalifrom the Arabian Sea, with a record ofHolanthias rhodopeplus(Günther) from Indian Seas

Trends in cyclonic disturbances for the period 1891-1997 were studied over Bay of Bengal and Arabian Sea. It is noticed that there is a significant decreasing trend at 99% level of confidence in the frequency of storms. The slopes of decreasing trend in cyclonic activity over Bay of Bengal and that over Arabian Sea were found to be maximum during last four decades. Weakening of Hadley circulation due to upper tropospheric warming may be one of the cause of this decreasing trend. There appears to be decrease in intensification of cyclonic disturbances in recent period.

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Oceanic response to cyclone moving in different directions over Indian Seas using IRG model

MAUSAM ◽

10.54302/mausam.v52i1.1685 ◽

2021 ◽

Vol 52 (1) ◽

pp. 163-174

Author(s):

A. A. DEO ◽

P. S. SALVEKAR ◽

S. K. BEHERA

Keyword(s):

Arabian Sea ◽

Sensitivity Study ◽

Initial Position ◽

Ocean Model ◽

Coriolis Parameter ◽

Ocean Response ◽

Oceanic Response ◽

Westward Movement ◽

The Right ◽

Indian Seas

The IITM Reduced Gravity (IRG) ocean model is employed to investigate the influence of tropical cyclone moving in different directions in Indian Seas. Some of the observed storm tracks in the Arabian Sea and Bay of Bengal are considered which have northward and westward movement. Sensitivity study is carried out for initial position of the storm at (90° E, 10° N) and moving in different directions. For westward moving cyclones the right bias in the model upper-layer thickness deviation (ULTD) field disappears. In an another experiment of westward moving cyclone originating at different latitudes, the ocean response is found to be sensitive to the Coriolis parameter (f). The surface currents as well as ULTD reduce, as f increases. The amplitude and the wavelength of inertia gravity wave increase with decrease in f, in the wake of the cyclone. This study helps to determine the upwelling region arising due to movement of the cyclone.

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Climatology of Energetics of cyclones over Indian Seas

Journal of Atmospheric Science Research ◽

10.30564/jasr.v2i1.266 ◽

2019 ◽

Vol 2 (1) ◽

Author(s):

Somenath Dutta ◽

Geena Sandhu ◽

Sanjay G Narkhedkar ◽

Sunitha Devi

Keyword(s):

Tropical Cyclones ◽

Bay Of Bengal ◽

Arabian Sea ◽

Monsoon Season ◽

Recent Decade ◽

Reanalysis Data ◽

Monsoon Period ◽

Post Monsoon ◽

Post Monsoon Season ◽

Indian Seas

The study discusses the energetic aspects of tropical cyclones formed over Arabian Sea (AS) and Bay of Bengal (BOB) during the period from 1991 till 2013 and aims at bringing out climatology of the energetics of tropical cyclones over Indian Seas. Total 88 cyclones that developed over the Indian Seas during the recent decade of 1991-2013 have been studied. These intense systems are categorized on the basis of their formation region and season of formation. It is seen that during the study period, the frequency of formation of cyclones over BOB is twice that over AS which is consistent with the climatology of the regions. Further, it is noticed that over both the regions, they are more frequently formed in the post monsoon period compared to pre monsoon. The trend analysis of the frequency of cyclones forming over both basins, season wise shows that the overall trend for both basins is of just decreasing type. However, for Arabian Sea; the decreasing trend is more apparent in the post monsoon season, whereas in the case of the Bay of Bengal the decreasing trend is more evident in the pre monsoon season. Various energy terms, their generation and conversion terms have been computed using NCEP/NCAR reanalysis data. Day to day quantitative analysis of these parameters is studied critically during various stages of the cyclones. The composites of these categorized systems are formed and studied. The formative, intensification and dissipation stages showed variations in their energy terms.

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Latitudinal distribution of water vapour over the Arabian Sea and Bay of Bengal using Bhaskara-II SAMIR data

MAUSAM ◽

10.54302/mausam.v43i4.3506 ◽

2021 ◽

Vol 43 (4) ◽

pp. 385-394

Author(s):

P.N. PATHAK ◽

N. GAUTAM

Keyword(s):

Water Vapour ◽

Bay Of Bengal ◽

Arabian Sea ◽

Latitudinal Gradient ◽

Southwest Monsoon ◽

Climatological Data ◽

Latitude Range ◽

Uniform Value ◽

Northern Winter ◽

Indian Seas

The main purpose of the present work is to establish the reliability of the SAMIR-derived water vapour (WV) data over the Arabian Sea and the Bay of Bengal for the entire 18-month from January 1982 to June 1983 period of the in-orbit operation of the SAMIR system. The average latitudinal distributions of WV over the Arabian Sea and Bay of Bengal for different months, derived from the SAMJR data were found to be broadly consistent with the climatological data on WV from the coastal and island radiosonde stations. A significant latitudinal gradient in WV has been found during the northern winter months (Dec-Feb) with the highest value of 4-5 gm/cm2 near the equator and thc lowest value of about 2 gm/cm2 at about 20oN over the Indian seas. This gradient gradually decreases during the subsequent months and almost vanishes during the southwest monsoon months (Jun-Sep) when the WV has nearly uniform value of 4-5 gm/cm2 in the entire latitude range from the equator to 20oN over the Indian seas. Finally, it has been found that WV values over the Bay of Bengal are generally higher than those over the Arabian Sea at co-latitudinal positions. The implications of this result are discussed in the light of other considerations.

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Cyclonic storms and Depressions over the north Indian Ocean during 2019*

MAUSAM ◽

10.54302/mausam.v71i3.35 ◽

2021 ◽

Vol 71 (3) ◽

pp. 357-376

Author(s):

Kashyapi A ◽

Shripad V K ◽

Natu J C

Keyword(s):

Arabian Sea ◽

Monsoon Season ◽

North Indian Ocean ◽

Cyclonic Storm ◽

Post Monsoon ◽

The North ◽

Post Monsoon Season ◽

Severe Cyclonic Storm ◽

Cyclonic Storms ◽

Indian Seas

During 2019, in all 12 intense low pressure systems formed over the Indian Seas. These include; one Super cyclonic storm (KYARR), one extremely severe cyclonic storm (FANI), 4 very Severe Cyclonic Storms (VAYU, HIKAA, MAHA & BULBUL), 2 Cyclonic Storms (PABUK & PAWAN), 3 Deep Depressions and 1 Depression. Out of these 12 systems, 4 systems formed over the Bay of Bengal and 8 over the Arabian Sea. Arabian Sea remained exceptionally active in terms of cyclogenesis this year, especially in the post monsoon season. The season-wise distribution had been one cyclonic storm in winter, one in pre-monsoon season, 2 depressions and 2 very severe cyclonic storms during the monsoon season and 4 cyclonic storms and 3 depressions in Post monsoon season.

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Multiple variability of summer sea surface temperature (SST) and evaporation over the Indian Seas

MAUSAM ◽

10.54302/mausam.v50i4.1946 ◽

2021 ◽

Vol 50 (4) ◽

pp. 355-342

Author(s):

O. P. SINGH

Keyword(s):

Surface Temperature ◽

Sea Surface Temperature ◽

Bay Of Bengal ◽

Arabian Sea ◽

Evaporation Rate ◽

Function Analysis ◽

Meteorological Data ◽

North Indian Ocean ◽

Sea Surface ◽

Indian Seas

Utilising thirty one years' marine meteorological data from 1961-91 recorded over the north Indian Ocean the sea surface temperature (SST) and evaporation have been obtained for different regions of the Arabian Sea and the Bay of Bengal. The moving pentad averages of SST and evaporation reveal increasing tendencies of both the parameters over the Arabian Sea and that of evaporation over the Bay of Bengal during May. The changes are real and significant as revealed by the trend analysis. The spectral analysis shows that SST has a 2-3 year significant cycle and evaporation rate has a 2-5 year cycle over the Indian Seas. In addition, a significant 15-year cycle is present in the SST over the Bay of Bengal and evaporation rate over the Arabian Sea. Empirical orthogonal function analysis performed on the anomalies of SST and evaporation rate over the Arabian Sea and the Bay of Bengal reveals that the time coefficient of first EOF has an increasing tendency.

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