Correlation of interannual sea level variations in the Indian Ocean from Topex/Poseidon altimetry, temperature data and tide gauges with ENSO

2004 ◽  
Vol 43 (3-4) ◽  
pp. 183-196 ◽  
Author(s):  
V.M. Tiwari ◽  
C. Cabanes ◽  
K. DoMinh ◽  
A. Cazenave
Keyword(s):  
Indian Ocean ◽  
Sea Level ◽  
Temperature Data ◽  
Tide Gauges ◽  
The Indian Ocean ◽  
Sea Level Variations

scholarly journals Decadal Sea Level Variations in the Indian Ocean Investigated with HYCOM: Roles of Climate Modes, Ocean Internal Variability, and Stochastic Wind Forcing*

2015 ◽  
Vol 28 (23) ◽  
pp. 9143-9165 ◽  
Author(s):  
Yuanlong Li ◽  
Weiqing Han
Keyword(s):  
Heat Flux ◽  
Indian Ocean ◽  
Sea Level ◽  
Surface Heat Flux ◽  
Internal Variability ◽  
Surface Heat ◽  
Wind Forcing ◽  
Sea Level Variability ◽  
The Indian Ocean ◽  
Sea Level Variations

Abstract In this study decadal (≥10 yr) sea level variations in the Indian Ocean (IO) during 1950–2012 are investigated using the Hybrid Coordinate Ocean Model (HYCOM). The solution of the main run agrees well with observations in the western-to-central IO. Results of HYCOM experiments reveal large spatial variations in the mechanisms of decadal sea level variability. Within the tropical IO (north of 20°S), decadal sea level variations achieve maximum amplitude in the south IO thermocline ridge region. They are predominantly forced by decadal fluctuations of surface wind stress associated with climate variability modes, while the impact of other processes is much smaller. The Somali coast and the western Bay of Bengal are two exceptional regions, where ocean internal (unforced) variability has large contribution. Between 28° and 20°S in the subtropical south IO, surface heat flux and ocean internal variability are the major drivers of decadal sea level variability. Heat budget analysis for the upper 300 m of this region suggests that surface heat flux affects regional thermosteric sea level through both local surface heating and heat transport by ocean circulation. In the southwestern IO south of 30°S, where stochastic winds are strong, stochastic wind forcing and its interaction with ocean internal variability generate pronounced decadal variations in sea level. The comprehensive investigation of decadal sea level variability over the IO from an oceanic perspective will contribute to decadal sea level prediction research, which has a high societal demand.

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 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

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