Circulation in the region of the West India Coastal Current in March 1994 hydrographic and altimeter data

Marine sediments from the West Greenland margin represent high-resolution archives of Holocene climate history, past ice sheet dynamics, changes in meltwater discharge and coastal current intensities. We investigate potential changes of sediment provenances using strontium (Sr) and neodymium (Nd) radiogenic isotopes as tracers for the origin and pathways of the silicate detrital fraction in marine sediments. Meltwater discharge and coastal currents are the most important transport pathways for detrital sediments into (northeast) Labrador Sea, which is an important pathway for freshwater from the Arctic Ocean and meltwater from the Greenland Ice Sheet to enter the North Atlantic, where deep water formation takes place. Variations in freshwater supply into Labrador Sea may influence deep water formation and therefore further circulation and climate patterns on a global scale.The marine sediment record collected in Nuuk Trough, southwest Greenland, displays uniform isotopic compositions throughout most of the Holocene, indicating well mixed detrital material from local sources through meltwater discharge and distal sources transported via the West Greenland Current. From around 4 ka BP to present the composition of Nd isotopes reveals a steep (&#949;Nd: -29 to -35) and the Sr isotope composition a slight (87Sr/86Sr: 0.723 to 0.728) but pronounced shift. This time interval coincides with the transition into the Neoglacial time period [1], which is characterized by a significant drop in atmospheric temperatures [2], and the onset of the modern Labrador Sea circulation pattern (e.g. [3]). We suggest that the shift in Nd and Sr isotopes indicates a change towards less distal and more local sediment sources, possibly caused by enhanced erosion of the local bedrock during Neoglacial ice advance [4], along with a decrease in meltwater discharge [5] and coastal current strength, leading to a sediment delivery shift.[1] Funder & Fredskild (1989) Quaternary geology of Canada and Greenland, 775&#8211;783. [2] Seidenkrantz et al. (2007) The Holocene 17, 387-401. [3] Fagel et al. (2004) Paleoceanography 19, PA3002. [4] Funder et al. (2011) Developments in Quaternary Sciences 15, 699-713, (and references therein). [5] M&#248;ller et al. (2006) The Holocene 16, 685-695.

Download Full-text

Study of the Effective Factors on Shelf Currents in the Southern Caspian Sea

Journal of Marine Science ◽

10.30564/jmsr.v1i1.550 ◽

2019 ◽

Vol 1 (1) ◽

Author(s):

Maryam ShieaAli

Keyword(s):

Caspian Sea ◽

Low Frequency ◽

Coastal Current ◽

Surface Currents ◽

Measured Temperature ◽

The Caspian Sea ◽

The West ◽

Southwestern Part ◽

Significant Difference ◽

Weak Winds

The current and wind records and the physical parameter structures such as temperature and salinity in the southwestern part of the Caspian Sea adjacent to Anzali Port were investigated from November 2004 up to the end of January 2005. Results show that, despite the existence of relatively weak winds along the coast in the area, the measurements indicate strong long shore currents. However, when heavy wind tension is observed in the area, then strong currents are also present, which - from the perspective of direction – also have good coordination with the wind. The direction of dominated currents was parallel to the coast from the west to the east. In most cases, the flow rate was identical from the surface to the seabed, and in this condition - because the values of the measured temperature points were almost identical-barotropic currents were present. However, in the autumn at some region, a significant difference was observed between the surface currents and subsurface currents due to temperature differences that affected the density and caused the creation of barclinic currents. Due to the high velocity of currents compared to wind velocity, and the intense slope of the coast and low-frequency movements in the area, we can hypothesize the existence of motions such as Kelvin waves and conclude that the effect of the wind compared to the other factors of the coastal current in the area was weaker.

Download Full-text

Mean Conditions and Seasonality of the West Greenland Boundary Current System near Cape Farewell

Journal of Physical Oceanography ◽

10.1175/jpo-d-20-0086.1 ◽

2020 ◽

Vol 50 (10) ◽

pp. 2849-2871

Author(s):

Astrid Pacini ◽

Robert S. Pickart ◽

Frank Bahr ◽

Daniel J. Torres ◽

Andrée L. Ramsey ◽

...

Keyword(s):

Current System ◽

Labrador Sea ◽

Western Boundary ◽

Coastal Current ◽

Boundary Current ◽

The West ◽

West Greenland ◽

Irminger Sea ◽

West Greenland Current ◽

Recirculation Gyre

AbstractThe structure, transport, and seasonal variability of the West Greenland boundary current system near Cape Farewell are investigated using a high-resolution mooring array deployed from 2014 to 2018. The boundary current system is comprised of three components: the West Greenland Coastal Current, which advects cold and fresh Upper Polar Water (UPW); the West Greenland Current, which transports warm and salty Irminger Water (IW) along the upper slope and UPW at the surface; and the Deep Western Boundary Current, which advects dense overflow waters. Labrador Sea Water (LSW) is prevalent at the seaward side of the array within an offshore recirculation gyre and at the base of the West Greenland Current. The 4-yr mean transport of the full boundary current system is 31.1 ± 7.4 Sv (1 Sv ≡ 106 m3 s−1), with no clear seasonal signal. However, the individual water mass components exhibit seasonal cycles in hydrographic properties and transport. LSW penetrates the boundary current locally, through entrainment/mixing from the adjacent recirculation gyre, and also enters the current upstream in the Irminger Sea. IW is modified through air–sea interaction during winter along the length of its trajectory around the Irminger Sea, which converts some of the water to LSW. This, together with the seasonal increase in LSW entering the current, results in an anticorrelation in transport between these two water masses. The seasonality in UPW transport can be explained by remote wind forcing and subsequent adjustment via coastal trapped waves. Our results provide the first quantitatively robust observational description of the boundary current in the eastern Labrador Sea.

Download Full-text

Observational evidence for remote forcing of the West India Coastal Current

Journal of Geophysical Research Atmospheres ◽

10.1029/2008jc004874 ◽

2008 ◽

Vol 113 (C11) ◽

Cited By ~ 23

Author(s):

S. R. Shetye ◽

I. Suresh ◽

D. Shankar ◽

D. Sundar ◽

S. Jayakumar ◽

...

Keyword(s):

Observational Evidence ◽

Coastal Current ◽

The West ◽

Remote Forcing

Download Full-text

Spatial variations in zooplankton community structure along the Japanese coastline in the Japan Sea: influence of the coastal current

10.5194/os-2017-91 ◽

2017 ◽

Author(s):

Taketoshi Kodama ◽

Taku Wagawa ◽

Naoki Iguchi ◽

Yoshitake Takada ◽

Takashi Takahashi ◽

...

Keyword(s):

Community Structure ◽

Zooplankton Community ◽

Japan Sea ◽

Spatial Variations ◽

Coastal Current ◽

The West ◽

Zooplankton Community Structure ◽

Japanese Coast ◽

Toyama Bay ◽

The Japan Sea

Abstract. This study evaluates spatial variations in zooplankton community structure and potential controlling factors along the Japanese coast under the influence of the coastal branch of the Tsushima Warm Current (CBTWC). Variations in the density of morphologically-identified zooplankton in the surface layer in May were investigated for a 15-year period. The density of zooplankton (individuals per cubic meter) varied between sampling stations, but there was no consistent west–east trend. Instead, there were different zooplankton community structures in the west and east, with that in Toyama Bay particularly distinct: Corycaeus affinis and Calanus sinicus were dominant in the west and Oithona atlantica was dominant in Toyama Bay. Distance-based redundancy analysis (db-RDA) was used to characterize the variation in zooplankton community structure, and four axes (RD1–4) provided significant explanation. RD2–4 only explained

Download Full-text

Mesoscale process-induced variation of the West India Coastal Current during the winter monsoon

Environmental Monitoring and Assessment ◽

10.1007/s10661-015-4701-5 ◽

2015 ◽

Vol 187 (8) ◽

Cited By ~ 5

Author(s):

V. K. Jineesh ◽

K. R. Muraleedharan ◽

K. Lix John ◽

C. Revichandran ◽

P. V. Hareesh Kumar ◽

...

Keyword(s):

Winter Monsoon ◽

Coastal Current ◽

The West ◽

Induced Variation ◽

Mesoscale Process

Download Full-text

The Antarctic Coastal Current in the Bellingshausen Sea

The Cryosphere ◽

10.5194/tc-15-4179-2021 ◽

2021 ◽

Vol 15 (9) ◽

pp. 4179-4199

Author(s):

Ryan Schubert ◽

Andrew F. Thompson ◽

Kevin Speer ◽

Lena Schulze Chretien ◽

Yana Bebieva

Keyword(s):

Coastal Current ◽

Boundary Current ◽

The West ◽

Amundsen Sea ◽

West Antarctic Ice Sheet ◽

Ice Shelves ◽

West Antarctic ◽

Bellingshausen Sea ◽

Basal Melting ◽

The Antarctic

Abstract. The ice shelves of the West Antarctic Ice Sheet experience basal melting induced by underlying warm, salty Circumpolar Deep Water. Basal meltwater, along with runoff from ice sheets, supplies fresh buoyant water to a circulation feature near the coast, the Antarctic Coastal Current (AACC). The formation, structure, and coherence of the AACC has been well documented along the West Antarctic Peninsula (WAP). Observations from instrumented seals collected in the Bellingshausen Sea offer extensive hydrographic coverage throughout the year, providing evidence of the continuation of the westward flowing AACC from the WAP towards the Amundsen Sea. The observations reported here demonstrate that the coastal boundary current enters the eastern Bellingshausen Sea from the WAP and flows westward along the face of multiple ice shelves, including the westernmost Abbot Ice Shelf. The presence of the AACC in the western Bellingshausen Sea has implications for the export of water properties into the eastern Amundsen Sea, which we suggest may occur through multiple pathways, either along the coast or along the continental shelf break. The temperature, salinity, and density structure of the current indicates an increase in baroclinic transport as the AACC flows from the east to the west, and as it entrains meltwater from the ice shelves in the Bellingshausen Sea. The AACC acts as a mechanism to transport meltwater out of the Bellingshausen Sea and into the Amundsen and Ross seas, with the potential to impact, respectively, basal melt rates and bottom water formation in these regions.

Download Full-text