Trade wind forcing of upwelling, seasonality, and Heinrich events as a response to sub-Milankovitch climate variability

被引:88
作者
Little, MG
Schneider, RR
Kroon, D
Price, B
Summerhayes, CP
Segl, M
机构
[1] UNIV BREMEN,FACHBEREICH GEOWISSENSCH,D-28359 BREMEN,GERMANY
[2] SOUTHAMPTON OCEANOG CTR,SOUTHAMPTON SO14 3ZH,HANTS,ENGLAND
来源
PALEOCEANOGRAPHY | 1997年 / 12卷 / 04期
关键词
D O I
10.1029/97PA00823
中图分类号
P [天文学、地球科学];
学科分类号
07 ;
摘要
Planktonic foraminifera recovered from two cores in the northern Benguela upwelling system reveal a history of rapid events with a variability at sub-Milankovitch frequencies during the last 140 kyr, The ''cold-water'' planktonic foraminifer, left coiling Neogloboquadrina pachyderma (Ehrenberg), shows rapid fluctuations in relative abundance, indicating changes in upwelling: intensity. The periods of high abundance in left coiling N. pachyderma are referred to as ''PS events'' (pachyderma sinistral) and indicate increased intensity and zonality of the South Atlantic trade winds controlling the Benguela upwelling system. The good correlation between PS events, the North Atlantic Heinrich events, and the Dansgaard-Oeschger cycles from the Greenland Ice Sheet Program (GISP2) ice core suggests large-scale global oceanographic or climatic teleconnections between the South and North Atlantic via the trade wind system. The radiocarbon constrained timing of PS events younger than 45 kyr indicates that the South Atlantic leads the North Atlantic's response to trade wind changes, particularly during isotope stages 4-2 when the Earth was dominated by large ice sheets. At times of increased trade wind strength, tropical and subtropical waters are forced across the equator enhancing the pool of warm water to be transferred to the high latitudes of the North Atlantic via the Gulf Stream and North Atlantic Drift, increasing the pull of the thermohaline convective conveyor, The increased supply of wan water to the polar regions of the northern hemisphere increases the ice-ocean moisture gradient and accelerates ice sheet growth, leading to eventual instability and collapse.
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收藏
页码:568 / 576
页数:9
相关论文
共 89 条
  • [11] BERGER A, 1984, MILANKOVITCH CLIMATE
  • [12] BERGER WH, 1990, GLOBAL PLANET CHANGE, V89, P219, DOI 10.1016/0921-8181(90)90018-8
  • [13] EVIDENCE FOR MASSIVE DISCHARGES OF ICEBERGS INTO THE NORTH-ATLANTIC OCEAN DURING THE LAST GLACIAL PERIOD
    BOND, G
    HEINRICH, H
    BROECKER, W
    LABEYRIE, L
    MCMANUS, J
    ANDREWS, J
    HUON, S
    JANTSCHIK, R
    CLASEN, S
    SIMET, C
    TEDESCO, K
    KLAS, M
    BONANI, G
    IVY, S
    [J]. NATURE, 1992, 360 (6401) : 245 - 249
  • [14] CORRELATIONS BETWEEN CLIMATE RECORDS FROM NORTH-ATLANTIC SEDIMENTS AND GREENLAND ICE
    BOND, G
    BROECKER, W
    JOHNSEN, S
    MCMANUS, J
    LABEYRIE, L
    JOUZEL, J
    BONANI, G
    [J]. NATURE, 1993, 365 (6442) : 143 - 147
  • [15] BOULTON GS, 1994, NATO ASI SER, V122, P177
  • [16] THE CHRONOLOGY OF THE LAST DEGLACIATION: IMPLICATIONS TO THE CAUSE OF THE YOUNGER DRYAS EVENT
    Broecker, W. S.
    Andree, M.
    Wolfli, W.
    Oeschger, H.
    Bonani, G.
    Kennett, J.
    Peteet, D.
    [J]. PALEOCEANOGRAPHY, 1988, 3 (01): : 1 - 19
  • [17] THE INFLUENCE OF AIR AND SEA EXCHANGE ON THE CARBON ISOTOPE DISTRIBUTION IN THE SEA
    Broecker, Wallace
    Maier-Reimer, Ernst
    [J]. GLOBAL BIOGEOCHEMICAL CYCLES, 1992, 6 (03) : 315 - 320
  • [18] A SALT OSCILLATOR IN THE GLACIAL ATLANTIC? 1. THE CONCEPT
    Broecker, Wallace S.
    Bond, Gerard
    Klas, Millie
    Bonani, Georges
    Wolfli, Willy
    [J]. PALEOCEANOGRAPHY, 1990, 5 (04): : 469 - 477
  • [19] THE ROLE OF OCEAN-ATMOSPHERE REORGANIZATIONS IN GLACIAL CYCLES
    BROECKER, WS
    DENTON, GH
    [J]. GEOCHIMICA ET COSMOCHIMICA ACTA, 1989, 53 (10) : 2465 - 2501
  • [20] DOES THE OCEAN-ATMOSPHERE SYSTEM HAVE MORE THAN ONE STABLE MODE OF OPERATION
    BROECKER, WS
    PETEET, DM
    RIND, D
    [J]. NATURE, 1985, 315 (6014) : 21 - 26