Southwest Monsoon Circulation and Environments of Recent Planktonic Foraminifera in the Northwestern Arabian Sea

American Geophysical Union (AGU) - Tập 7 Số 6 - Trang 799-813 - 1992
John C. Brock, Charles R. McClain, David M. Anderson, Warren L Prell, William W. Hay

Tóm tắt

Digital hydrographic data combined with satellite thermal infrared and visible band remote sensing provide a synoptic climatological view of the shallow planktonic environment. This paper uses wind, hydrographic, and ocean remote sensing data to examine southwest monsoon controls on the foraminiferal faunal composition of Recent seafloor sediments of the northwestern Arabian Sea. Ekman pumping resulting in open‐ocean upwelling and coastal upwelling create two distinctly different mixed layer plankton environments in the northwestern Arabian Sea during the summer monsoon. Open‐sea upwelling to the northwest of the mean July position of the Findlater Jet axis yields a mixed layer environment with temperatures of less than 25°C to about 26.5°C, phytoplankton pigment concentrations between 1.5 and 5.0 mg/m³, and mixed layer depths less than 50 m. Convergence in the Ekman layer in the central Arabian Sea drives the formation of a mixed layer that is greater than 50 m thick, warmer than about 26.5°C, and has phytoplankton pigment concentrations generally below 2.0 mg/m³. Coastal upwelling creates an extremely eutrophic plankton environment that persists over and immediately adjacent to the Omani shelf and undergoes significant offshore transport only within topographically induced coastal squirts. The foraminiferal faunal composition of upper Pleistocene deep‐sea sediments of the northwestern Arabian Sea are mainly controlled by vertical nutrient fluxes caused by Ekman pumping, not coastal upwelling. Transfer functions for late Pleistocene mixed layer depth, temperature, and chlorophyll have been obtained through factor analysis and nonlinear multiple regression between late summer mixed layer environment and Recent sediment faunal observations.

Từ khóa


Tài liệu tham khảo

Anderson D. M. Foraminifer evidence of monsoon upwelling off Oman during the late Quaternary Ph.D. thesis Brown Univ. Providence R.I. 1991.

10.2973/odp.proc.sr.117.144.1991

10.1016/0198-0149(91)90062-K

Bé A. W. H., 1977, Oceanic Micropaleontology, 1

10.2307/1485406

Be A. W. H., 1971, The Micropaleontology of Oceans, 105

Bottero J. S. An analysis of upwelling off the southeast Arabian coast during the summer monsoon M.S. thesis Oregon State Univ. 70 Corvallis 1969.

10.1029/91JC02225

Brock J. C, 1991, The phytoplankton bloom in the northwestern Arabian Sea during the southwest monsoon of 1979, J. Geophys. Res., 642, 623

Bruce J. G., 1974, Some details of upwelling off the Somali and Arabian coasts, J. Mar. Res., 32, 419

10.1016/0377-8398(84)90022-7

Curry W. B., 1992, Upwelling Systems: Evolution Since the Early Miocene, 93

Darzi M. J. K.Firestone G.Fu C. R.McClain Current efforts regarding the SEAPAK oceanographie analysis systemProceedings of Seventh Conference on Interactive and Information Processing Systems for Meteorology Hydrology and Oceanography 109–115American Meteorological SocietyBoston Mass. 1991.

10.1029/JC090iC03p04741

10.1029/JC093iC06p06857

10.1002/j.1477-8696.1974.tb04329.x

Flament P., 1985, The evolving structure of an upwelling filament, J. Geophys. Res., 778, 765

10.1364/AO.20.004175

10.1364/AO.22.000020

Hutson W. H., 1980, A paleoecological transfer function, Fl‐2, for Indian Ocean planktonic foraminifera, J. Paleontol., 54, 381

Imbrie J., 1971, The Late Cenozoic Glacial Ages, 71

Kelly K. A., 1985, The influence of winds and topography on the surface temperature patterns over the northern California slope, J. Geophys. Res., 798, 783

10.1029/JC091iC06p07680

Kroon D., 1988, Planktonic Foraminifers as Tracers of Ocean‐Climate History, 229

10.1175/1520-0493(1989)117<0709:OAOPOT>2.0.CO;2

Levitus S. Climatological atlas of the world oceanNOAA Prof. Pap. 13 173 US Gov. Print. Off. Washington D.C. 1982.

10.1029/PA005i003p00433

10.1029/JC093iC09p10675

10.1029/JC095iC10p18027

10.1029/JC094iC11p16097

10.1357/002224086788401639

10.1038/338749a0

Pond S., 1986, Introductory Dynamic Oceanography

10.1029/GM029p0048

Prell W. L., 1981, Faunal and isotopic indices of monsoonal upwelling: Western Arabian Sea, Oceanol. Acta, 4, 91

10.1029/PA005i003p00447

10.1029/PA005i003p00409

10.1144/GSL.SP.1992.049.01.46

Smith R. L., 1977, A Voyage of Discovery, 291

10.2973/odp.proc.sr.117.167.1991

10.2973/odp.proc.sr.117.159.1991

Wrytki K., 1973, The Biology of the Indian Ocean, 18

Yoshida K., 1957, A theory of upwelling of large horizontal extent, J. Mar. Res., 16, 40

Thông tin
Thông tin xuất bản

American Geophysical Union (AGU)

Tập 7 Số 6

799-813

Thông tin tác giả