Salinity maxima in the upper 1000 metres of the North Indian Ocean

1964 ◽  
Vol 15 (1) ◽  
pp. 1 ◽  
Author(s):  
DJ Rochford
Keyword(s):  
Indian Ocean ◽  
Arabian Sea ◽  
Equatorial Region ◽  
North Indian Ocean ◽  
Water Masses ◽  
The Other ◽  
Flow Paths ◽  
Hydrological Data ◽  
The North ◽  
The Indian Ocean

The comprehensive hydrological data from cruise 31 of R.S. Vityaz in the north Indian Ocean have been used to identify all salinity maxima of the upper 1000 m. On the basis of density differences these salinity maxima have been grouped into five water masses. Three of these have been named according to their assumed origin; Red Sea, Persian Gulf, and Arabian Sea. The other two can not as yet be assigned origins, although one is confined largely to the northern part of the Arabian Sea and the other to the equatorial region of the Indian Ocean. Paths of flow of these water masses to the south and east have been established from salinity charts. Submarine topography in the Madagascar-Seychelles and Maldive-Chagos regions provides an explanation for the diversion and separation of the flow paths of these water masses.

First occurrence of the moray eel Gymnothorax prolatus Sasaki & Amaoka, 1991 (Teleostei: Anguilliformes: Muraenidae) from the northern Indian Ocean

2015 ◽  
Vol 8 ◽  
Author(s):  
Anil Mohapatra ◽  
Dipanjan Ray ◽  
David G. Smith
Keyword(s):  
Indian Ocean ◽  
Arabian Sea ◽  
Western Indian Ocean ◽  
Northern Indian Ocean ◽  
The North ◽  
First Occurrence ◽  
The Indian Ocean ◽  
First Time ◽  
North Western ◽  
Moray Eel

Gymnothorax prolatusis recorded for the first time from the Indian Ocean on the basis of four specimens collected in the Bay of Bengal off India and one from the Arabian Sea off Pakistan. These records extend the range of the species from Taiwan to the north-western Indian Ocean.

scholarly journals Annual, Seasonal, and Interannual Variability of Air–Sea Heat Fluxes in the Indian Ocean

2007 ◽  
Vol 20 (13) ◽  
pp. 3190-3209 ◽  
Author(s):  
Lisan Yu ◽  
Xiangze Jin ◽  
Robert A. Weller
Keyword(s):  
Heat Flux ◽  
Indian Ocean ◽  
Interannual Variability ◽  
Seasonal Cycle ◽  
Arabian Sea ◽  
Heat Fluxes ◽  
The Other ◽  
Net Heat Flux ◽  
The Indian Ocean ◽  
The Mean

Abstract This study investigated the accuracy and physical representation of air–sea surface heat flux estimates for the Indian Ocean on annual, seasonal, and interannual time scales. Six heat flux products were analyzed, including the newly developed latent and sensible heat fluxes from the Objectively Analyzed Air–Sea Heat Fluxes (OAFlux) project and net shortwave and longwave radiation results from the International Satellite Cloud Climatology Project (ISCCP), the heat flux analysis from the Southampton Oceanography Centre (SOC), the National Centers for Environmental Prediction reanalysis 1 (NCEP1) and reanalysis-2 (NCEP2) datasets, and the European Centre for Medium-Range Weather Forecasts operational (ECMWF-OP) and 40-yr Re-Analysis (ERA-40) products. This paper presents the analysis of the six products in depicting the mean, the seasonal cycle, and the interannual variability of the net heat flux into the ocean. Two time series of in situ flux measurements, one taken from a 1-yr Arabian Sea Experiment field program and the other from a 1-month Joint Air–Sea Monsoon Interaction Experiment (JASMINE) field program in the Bay of Bengal were used to evaluate the statistical properties of the flux products over the measurement periods. The consistency between the six products on seasonal and interannual time scales was investigated using a standard deviation analysis and a physically based correlation analysis. The study has three findings. First of all, large differences exist in the mean value of the six heat flux products. Part of the differences may be attributable to the bias in the numerical weather prediction (NWP) models that underestimates the net heat flux into the Indian Ocean. Along the JASMINE ship tracks, the four NWP modeled mean fluxes all have a sign opposite to the observations, with NCEP1 being underestimated by 53 W m−2 (the least biased) and ECMWF-OP by 108 W m−2 (the most biased). At the Arabian Sea buoy site, the NWP mean fluxes also have an underestimation bias, with the smallest bias of 26 W m−2 (ERA-40) and the largest bias of 69 W m−2 (NCEP1). On the other hand, the OAFlux+ISCCP has the best comparison at both measurement sites. Second, the bias effect changes with the time scale. Despite the fact that the mean is biased significantly, there is no major bias in the seasonal cycle of all the products except for ECMWF-OP. The latter does not have a fixed mean due to the frequent updates of the model platform. Finally, among the four products (OAFlux+ISCCP, ERA-40, NCEP1, and NCEP2) that can be used for studying interannual variability, OAFlux+ISCCP and ERA-40 Qnet have good consistency as judged from both statistical and physical measures. NCEP1 shows broad agreement with the two products, with varying details. By comparison, NCEP2 is the least representative of the Qnet variabilities over the basin scale.

Source regions of oxygen maxima in intermediate depths of the Arabian Sea.

1966 ◽  
Vol 17 (1) ◽  
pp. 1 ◽  
Author(s):  
DJ Rochford
Keyword(s):  
Indian Ocean ◽  
Arabian Sea ◽  
Structural Features ◽  
The South ◽  
The North ◽  
Source Regions ◽  
South Indian ◽  
Indian Central ◽  
South West Monsoon ◽  
The Indian Ocean

Oxygen maxima, in relation to σt salinity maxima and minima, and other hydrological structural features, have been examined along three meridional sections of the Indian Ocean. These relations have provided a background for the interpretation of the water mass sources of oxygen maxima of the whole Indian Ocean. After grouping these oxygen maxima according to density, their salinities have been used to identify mixing circuits in which the following waters are involved: from the south (1) South Indian Central, (2) Subtropical oxygen maximum, (3) Antarctic Intermediate; from the east (4) Equatorial Frontal water; and from the north (5) Persian Gulf, and (6) Red Sea. The principal routes whereby oxygen-rich mixtures of these waters enter the Arabian Sea, during the south-west monsoon, have been determined. The directions of flow along several of these routes agreed with measured directions of current flow. Where these currents disagreed the measured current was generally very weak.

Anthropogenic iron deposition alters the ecosystem and carbon balance of the Indian Ocean over a centennial timescale

2020 ◽  
Author(s):  
Anh Pham ◽  
Takamitsu Ito
Keyword(s):  
Indian Ocean ◽  
Arabian Sea ◽  
Ocean Basin ◽  
Ecosystem Dynamics ◽  
Carbon Uptake ◽  
The South ◽  
Nutrient Deposition ◽  
The North ◽  
The Indian Ocean ◽  
The Impact

<p>Phytoplankton growth in the Indian Ocean is generally limited by macronutrients (nitrogen: N and phosphorus: P) in the north and by micronutrient (iron: Fe) in the south. Increasing anthropogenic atmospheric deposition of N and dissolved Fe (dFe) into the ocean can thus lead to significant responses from marine ecosystems in this ocean basin. Previous modeling studies investigated the impacts of anthropogenic nutrient deposition on the ocean, but their results are uncertain due to incomplete representations of Fe cycling. We use a state-of-the-art ocean ecosystem and Fe cycling model to evaluate the transient responses of ocean productivity and carbon uptake in the Indian Ocean, focusing on the centennial time scale. The model incorporates all major external sources and represents a complicated internal cycling process of Fe, thus showing significant improvements in reproducing observations. Sensitivity simulations show that after a century of anthropogenic deposition, increased dFe stimulates diatoms productivity in the southern Indian Ocean poleward of 50⁰S and the southeastern tropics. Diatoms production weakens in the south of the Arabian Sea due to the P limitation, and diatoms are outcompeted there by coccolithophores and picoplankton, which have a lower P demand. These changes in diatoms and coccolithophores productions alter the balance between the organic and carbonate pumps in the Indian Ocean, increasing the carbon uptake in the south of 50⁰S and the southeastern tropics while decreasing it in the Arabian Sea. Our results reveal the important role of ecosystem dynamics in controlling the sensitivity of carbon fluxes in the Indian Ocean under the impact of anthropogenic nutrient deposition over a centennial timescale.</p>

scholarly journals Art. XXVII.—Notes on Malayalam Literature

1900 ◽  
Vol 32 (4) ◽  
pp. 763-768
Author(s):  
T. K. Krishṇa Menon
Keyword(s):  
Indian Ocean ◽  
Arabian Sea ◽  
The South ◽  
The West ◽  
The Third ◽  
The North ◽  
South West ◽  
The Indian Ocean

Malayalam is the language of the south-west of the Madras Presidency. It is the third most important language of the Presidency, the first and the second being Tamil and Telugu respectively. It is spoken in Malabar, Cochin, and Travancore. Out of a total of 5,932,207 inhabitants of these parts, 5,409,350 persons are those who speak Malayalam. These countries, taken as a whole, are bounded on the north, by South Canara, on the east by the far-famed Malaya range of mountains, on the south by the Indian Ocean, and on the west by the Arabian Sea.

MEASURING POLICY BENEFITS OF THE CYCLONE SHELTER PROGRAM IN THE NORTH INDIAN OCEAN: PROTECTION FROM INTENSE WINDS OR HIGH STORM SURGES?

2017 ◽  
Vol 08 (04) ◽  
pp. 1750011 ◽  
Author(s):  
S. NIGGOL SEO
Keyword(s):  
Indian Ocean ◽  
Low Income ◽  
Arabian Sea ◽  
Negative Binomial ◽  
Storm Surges ◽  
North Indian Ocean ◽  
High Population Density ◽  
Cyclone Intensity ◽  
The North ◽  
Cyclone Shelter

This paper provides a quantitative estimate of the policy benefit of the cyclone shelter program (CSP) implemented in Bangladesh. The present author examines all cyclones that were generated in the North Indian Ocean, both the Bay of Bengal and the Arabian Sea, from 1990 to 2015. A negative binomial (NB) model of cyclone fatalities against cyclone intensity finds that the CSP does little in protecting people’s lives against the high storm intensity. In contrast, a two-stage NB model of cyclone fatalities against the level of surges reveals that the CSP is vastly effective against storm surges. The number of fatalities is, on average, 75% smaller in the areas where the shelter program has been implemented against the areas without the program in response to the same level of storm surges. A set of Probit adoption models of adaptation options in response to cyclone surges and intensity reveals that the CSP has been directed to a low-income area with high population density, which is in contrast to the other strategies which have been increasingly adopted with higher income, e.g., cyclone trajectory projection technologies.

scholarly journals A new amphipod species from the Indian Ocean (Crustacea: Amphipoda: Lysianassoidea: Podoprionidae)

Zootaxa ◽  
2005 ◽  
Vol 861 (1) ◽  
pp. 1
Author(s):  
TAMMY HORTON
Keyword(s):  
New Species ◽  
Indian Ocean ◽  
Arabian Sea ◽  
The Other ◽  
Amphipod Species ◽  
Northern Arabian Sea ◽  
The Indian Ocean ◽  
A New Species

A new species of the genus Podoprion is described. The species can be distinguished from the other species in the genus, Podoprion bolivari Chevreux, 1891, P. ruffoi Lowry & Stoddart, 1996, and P. mediterraneum Kaim-Malka, 2004, by the shape of gnathopod 2 propodus, coxa 4, number and size of serrations on pereopod 5 basis, and characters of the mouthparts. Material was collected by baited trap at 1185 m off the coast of Pakistan in the northern Arabian Sea.

scholarly journals Role of Rossby Waves in the Remote Effects of the North Indian Ocean Tropical Disturbances

2012 ◽  
Vol 140 (11) ◽  
pp. 3620-3633 ◽  
Author(s):  
J. V. Ratnam ◽  
S. K. Behera ◽  
Y. Masumoto ◽  
T. Yamagata
Keyword(s):  
Saudi Arabia ◽  
Indian Ocean ◽  
Bay Of Bengal ◽  
Arabian Sea ◽  
Rossby Waves ◽  
Temporal Distribution ◽  
North Indian Ocean ◽  
Positive Temperature ◽  
The North ◽  
Wide Range

Abstract Remote effects due to the tropical disturbances in the north Indian Ocean are investigated by analyzing long-lasting (≥5 days) tropical disturbances, which reached at least the strength of tropical storms. The present analysis is carried out for both the pre- and postmonsoon periods. The spatial and temporal distribution of the outgoing longwave radiation (OLR) during the premonsoon disturbances over the Bay of Bengal reveals several interesting features. Temporal distribution of the OLR anomalies shows that the intraseasonal oscillations play an important role in the formation of those disturbances. The spatial distribution of the OLR anomalies shows a dipole with negative OLR anomalies over the bay and positive OLR anomalies over the Indonesian region. The atmospheric response to the negative OLR anomalies results in positive temperature anomalies over northwest India, Pakistan, Afghanistan, Iran, and Saudi Arabia, remote from the disturbance; and the response to the positive anomalies causes slight increase in the sea surface temperature of the Arabian Sea. Negative OLR anomalies are also seen over western Japan due to the Rossby waves generated by the heating over the Bay of Bengal besides the enhancement of the so-called “Pacific–Japan” teleconnection pattern. However, the analysis shows that the postmonsoon disturbances over the Bay of Bengal and the disturbances formed over the Arabian Sea in both pre- and postmonsoon seasons do not develop remote teleconnections associated with the above type of Rossby wave mechanism. These results are significant for the short- to medium-range weather forecast over a wide range covering Japan, Pakistan, Afghanistan, Iran, and Saudi Arabia.

scholarly journals Variability in dynamic and thermodynamic parameters in cyclogenesis over north Indian ocean

MAUSAM ◽  
2021 ◽  
Vol 60 (1) ◽  
pp. 61-72
Author(s):  
A. MUTHUCHAMI
Keyword(s):  
Indian Ocean ◽  
Thermodynamic Parameters ◽  
Bay Of Bengal ◽  
Arabian Sea ◽  
Threshold Level ◽  
Reanalysis Data ◽  
North Indian Ocean ◽  
The North ◽  
Static Instability ◽  
The Difference

The two basins Arabian sea (ARS) and Bay of Bengal (BOB) of the North Indian Ocean (NIO) are having different dynamic and thermodynamic character and therefore ARS has subdued cyclone activity than BOB. In order to examine the difference between these basins in respect of various meteorological parameters, using NCEP/NCAR reanalysis data for the period 1971-2005 during the months of September to December the distribution of the dynamic and thermodynamic parameters are discussed. It is seen that sea surface temperature (SST) is not responsible for subdued activity over ARS as the SST over ARS and BOB is mostly above minimum threshold level. In respect of wind shear, during October in ARS north of 10°  N is favourable for storm formation unlike September where the whole of Arabian sea except the region north of 20° N is inert to cyclone formation. The humidity factor is more pronounced in ARS for prohibiting storm formation than shear factor. In all the months static instability at 90° E is least and so the atmosphere is neutral throughout the period and consequence of it any small trigger in the lower level will induce the system to grow further.  The BOB is more barotropic than ARS. There is a considerable difference exists in precipitation rate as a consequence of more stable atmosphere over Arabian sea than in Bay of Bengal even at the lower level.

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