scholarly journals A discussion concerning the floor of the northwest Indian Ocean - Preface

1966 ◽  
Vol 259 (1099) ◽  
pp. 135-136
Keyword(s):  
Indian Ocean ◽  
Sea Level ◽  
Experimental Work ◽  
Royal Society ◽  
Research Programme ◽  
Woods Hole Oceanographic Institution ◽  
International Council ◽  
The Earth ◽  
The Indian Ocean ◽  
Lengthy Discussion

Some years ago at the first and preliminary meeting of the Scientific Committee on Oceanic Research (S. C. O. R.) of the International Council of Scientific Unions (I. C. S. U.), one of the prime tasks was to seek some major international sea-going undertaking which the Committee could initiate and subsequently sponsor. This undertaking would have to interest many nations and embrace many oceanographical disciplines. The meeting took place at the Woods Hole Oceanographic Institution and it was therefore appropriate (although not improbable!) that Dr C. H. O’D. Iselin should be first to suggest that an international research programme in the Indian Ocean fulfilled both these objects. He emphasized that many nations bordered it and that there were interests in this comparatively unknown ocean for any scientist concerned with meteorology, biology (above or below sea level), the physics and chemistry of the ocean waters, or the Earth beneath the sea. He also made clear that the monsoons made the Indian Ocean unique as regards oceanic and atmospheric circulation. The meeting, after lengthy discussion, endorsed Dr Iselin’s proposal and the end results of the tremendous international effort which thereby was created are now coming in. Some of these results were delivered at a Discussion Meeting held in the rooms of the Royal Society on 12 November 1964. The papers given at this meeting, and which are published below were restricted to geological and geophysical aspects of the northwest Indian Ocean (except for the first paper concerning the physiography of the whole of the Indian Ocean). This collection of papers represents, by no means, the last word on these aspects of this area. Indeed there is much more work to be published on experimental work already completed, and for many of us the work already accomplished has produced many new problems which require further experimental work in the area

Intraseasonal-to-Interannual Variability of South Indian Ocean Sea Level and Thermocline: Remote versus Local Forcing

2012 ◽  
Vol 42 (4) ◽  
pp. 602-627 ◽  
Author(s):  
Laurie L. Trenary ◽  
Weiqing Han
Keyword(s):  
Indian Ocean ◽  
Interannual Variability ◽  
Sea Level ◽  
Time Scales ◽  
Ekman Pumping ◽  
Remote Forcing ◽  
South Indian ◽  
The Pacific ◽  
The Indian Ocean ◽  
Thermocline Variability

Abstract The relative importance of local versus remote forcing on intraseasonal-to-interannual sea level and thermocline variability of the tropical south Indian Ocean (SIO) is systematically examined by performing a suite of controlled experiments using an ocean general circulation model and a linear ocean model. Particular emphasis is placed on the thermocline ridge of the Indian Ocean (TRIO; 5°–12°S, 50°–80°E). On interannual and seasonal time scales, sea level and thermocline variability within the TRIO region is primarily forced by winds over the Indian Ocean. Interannual variability is largely caused by westward propagating Rossby waves forced by Ekman pumping velocities east of the region. Seasonally, thermocline variability over the TRIO region is induced by a combination of local Ekman pumping and Rossby waves generated by winds from the east. Adjustment of the tropical SIO at both time scales generally follows linear theory and is captured by the first two baroclinic modes. Remote forcing from the Pacific via the oceanic bridge has significant influence on seasonal and interannual thermocline variability in the east basin of the SIO and weak impact on the TRIO region. On intraseasonal time scales, strong sea level and thermocline variability is found in the southeast tropical Indian Ocean, and it primarily arises from oceanic instabilities. In the TRIO region, intraseasonal sea level is relatively weak and results from Indian Ocean wind forcing. Forcing over the Pacific is the major cause for interannual variability of the Indonesian Throughflow (ITF) transport, whereas forcing over the Indian Ocean plays a larger role in determining seasonal and intraseasonal ITF variability.

Natural decadal sea-level variability in the Indian Ocean: lessons from CMIP models

2019 ◽  
Vol 53 (9-10) ◽  
pp. 5653-5673
Author(s):  
A. G. Nidheesh ◽  
Matthieu Lengaigne ◽  
Jérôme Vialard ◽  
Takeshi Izumo ◽  
A. S. Unnikrishnan ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Sea Level ◽  
Sea Level Variability ◽  
The Indian Ocean

scholarly journals Repeated evolution of flightlessness in Dryolimnas rails (Aves: Rallidae) after extinction and recolonization on Aldabra

2019 ◽  
Vol 186 (3) ◽  
pp. 666-672 ◽  
Author(s):  
Julian P Hume ◽  
David Martill
Keyword(s):  
Indian Ocean ◽  
Sea Level ◽  
Upper Pleistocene ◽  
Fossil Evidence ◽  
Before And After ◽  
Repeated Evolution ◽  
The Indian Ocean

AbstractThe Aldabra rail, Dryolimnas cuvieri subsp. aldabranus, endemic to the Aldabra Atoll, Seychelles, is the last surviving flightless bird in the Indian Ocean. Aldabra has undergone at least one major, total inundation event during an Upper Pleistocene (Tarantian age) sea-level high-stand, resulting in the loss of all terrestrial fauna. A flightless Dryolimnas has been identified from two temporally separated Aldabran fossil localities, deposited before and after the inundation event, providing irrefutable evidence that a member of Rallidae colonized the atoll, most likely from Madagascar, and became flightless independently on each occasion. Fossil evidence presented here is unique for Rallidae and epitomizes the ability of birds from this clade to successfully colonize isolated islands and evolve flightlessness on multiple occasions.

scholarly journals A 17-My-old whale constrains onset of uplift and climate change in east Africa

2015 ◽  
Vol 112 (13) ◽  
pp. 3910-3915 ◽  
Author(s):  
Henry Wichura ◽  
Louis L. Jacobs ◽  
Andrew Lin ◽  
Michael J. Polcyn ◽  
Fredrick K. Manthi ◽  
...  
Keyword(s):  
Indian Ocean ◽  
East Africa ◽  
Sea Level ◽  
Drainage System ◽  
Beaked Whale ◽  
East African ◽  
Surface Uplift ◽  
The Indian Ocean ◽  
Mantle Processes ◽  
The Impact

Timing and magnitude of surface uplift are key to understanding the impact of crustal deformation and topographic growth on atmospheric circulation, environmental conditions, and surface processes. Uplift of the East African Plateau is linked to mantle processes, but paleoaltimetry data are too scarce to constrain plateau evolution and subsequent vertical motions associated with rifting. Here, we assess the paleotopographic implications of a beaked whale fossil (Ziphiidae) from the Turkana region of Kenya found 740 km inland from the present-day coastline of the Indian Ocean at an elevation of 620 m. The specimen is ∼17 My old and represents the oldest derived beaked whale known, consistent with molecular estimates of the emergence of modern strap-toothed whales (Mesoplodon). The whale traveled from the Indian Ocean inland along an eastward-directed drainage system controlled by the Cretaceous Anza Graben and was stranded slightly above sea level. Surface uplift from near sea level coincides with paleoclimatic change from a humid environment to highly variable and much drier conditions, which altered biotic communities and drove evolution in east Africa, including that of primates.

Tsunami geoscience

2007 ◽  
Vol 31 (6) ◽  
pp. 575-590 ◽  
Author(s):  
Alastair Dawson ◽  
Iain Stewart
Keyword(s):  
Indian Ocean ◽  
Future Study ◽  
Royal Society ◽  
Charles Darwin ◽  
Late Quaternary ◽  
Indian Ocean Tsunami ◽  
Early Nineteenth Century ◽  
Lisbon Earthquake ◽  
The Indian Ocean ◽  
Over Time

Research in tsunami geoscience has accelerated markedly ever since the tragedy of the Indian Ocean tsunami of Boxing Day 2004. Yet, for many decades and centuries, scholars have been describing a multiplicity of tsunami events. Thus the Royal Society devoted a whole volume to the effects of the Great Lisbon earthquake and tsunami of November AD 1755 while in the early nineteenth century Charles Darwin was describing the great tsunami at Valdivia, Chile, in his account of the Voyage of the Beagle. Today, research in tsunami geoscience is still finding its feet. Thus, whereas there has been a wealth of publications on the reconstruction of Late Quaternary and Holocene tsunamis, the literature describing evidence for tsunamis in the geological record are rare. In this paper, we describe how our understanding of tsunamis has changed over time and we try also to identify areas of tsunami geoscience worthy of future study.

Bilharzia Infection in South Africa

Parasitology ◽  
1928 ◽  
Vol 20 (3) ◽  
pp. 250-253
Author(s):  
F. G. Cawston
Keyword(s):  
South Africa ◽  
Indian Ocean ◽  
Sea Level ◽  
Guinea Pigs ◽  
Source Of Infection ◽  
The Indian Ocean ◽  
Level I ◽  
The Town

In 1916 Dr J. C. Becker made the interesting discovery of Bilharzia infection in Physopsis africana collected at Nijlstroom in the Transvaal and obtained the adult flukes in some guinea-pigs he had exposed to infection with the cercariae. The town of Nijlstroom is situated at the source of a tributary of the Limpopo river at an altitude of 3924 feet above the Indian Ocean into which it flows. In 1917 I collected2 infested examples of P. africana at Magaliesburg, a popular picnic place for Krugersdorp residents, situated on a branch of the Little Crocodile river which later joins the Limpopo. Magaliesburg has an altitude of 5000 feet above sea-level. I also obtained infested examples from Rustenburg, thus revealing a further source of infection from tributaries of the Little Crocodile river, at an altitude of over 4000 feet.

Can Submerged Buoys be Reliably Used for Monitoring Tsunamis in the Indian Ocean?

2021 ◽  
Vol 55 (1) ◽  
pp. 127-136
Author(s):  
Ramasamy Venkatesan ◽  
Manickavasagam Arul Muthiah ◽  
Narayanaswamy Vedachalam ◽  
Karuppiah Thirumurugan ◽  
Punniyamoorthy Senthilkumar ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Sea Level ◽  
Health Monitoring ◽  
Bay Of Bengal ◽  
Event Data ◽  
On Demand ◽  
Level Data ◽  
The Indian Ocean ◽  
Warning Time ◽  
Tsunami Event

AbstractThe article proposes a novel and robust Continuously Homing Submerged Autonomous Tsunami Underwater System (CHATUR) in which the buoy is submerged at a depth of 300 m, collecting sea-level data during normal conditions and surfacing during a tsunami event to transmit the event data. By on-demand reliability analysis, a system in the Bay of Bengal requires health monitoring at an interval of 13 days. By offshore experiments and numerical simulations, the configuration increases the tsunami warning time by ~2 min.

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