LAGRANGIAN FLOW OBSERVATIONS OF THE AMAZON RIVER DISCHARGE INTO THE NORTH-ATLANTIC

被引:46
作者
LIMEBURNER, R
BEARDSLEY, RC
SOARES, ID
LENTZ, SJ
CANDELA, J
机构
[1] WOODS HOLE OCEANOG INST, DEPT PHYS OCEANOG, WOODS HOLE, MA 02543 USA
[2] FDN UNIV RIO GRANDE, DEPT FIS, RIO GRANDE, BRAZIL
关键词
D O I
10.1029/94JC03223
中图分类号
P7 [海洋学];
学科分类号
0707 ;
摘要
Nine satellite-tracked drifters with near-surface drogues were launched in or near the mouth of the Amazon River on the north Brazil shelf during 1989-1991 at four different stages of river discharge. The drifters initially moved along shelf toward the northwest over the north Brazil shelf with mean speeds varying from 41 to 128 cm/s and a maximum along-shelf velocity of 197 cm/s. Many drifters experienced strong acceleration near 2 degrees N between the 5-m and 20-m isobaths, caused in part by the sharp reduction in cross-shelf cross-sectional area near the shore-perpendicular Cabo Norte shoal. The drifter trajectories showed strong cross-shelf tidal variability in the flow field near the Amazon River mouth, and the largest low-frequency, along-shelf variability was located over the open shelf just north of Cabo Norte. Good visual correlation between drifter along-shelf velocity and along-shelf wind stress supports the dynamical model of Lentz (this issue) that subtidal fluctuations in near-surface along-shelf currents in the Amazon River Plume are strongly wind driven. Drifters left the north Brazil shelf after about 5 to 30 days. Three drifters moved northwestward parallel to the northeast coast of South America, crossed the shelf break near 8 degrees N, and moved into deeper North Atlantic water where they began looping in anticyclonic eddies (often called retroflection eddies or loopers) with periods of approximately 11 days as they moved northwestward to the Caribbean Sea. Four drifters initially moved along shelf toward the northwest and then offshore between 3 degrees N and 7 degrees N, where they followed the retroflection of the North Brazil Current. Only one drifter entered the zonal current system that characterizes the equatorial Atlantic circulation.
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页码:2401 / 2415
页数:15
相关论文
共 23 条
[1]  
Baumgartner A., 1975, WORLD WATER BALANCE
[2]   THE M(2) TIDE ON THE AMAZON SHELF [J].
BEARDSLEY, RC ;
CANDELA, J ;
LIMEBURNER, R ;
GEYER, WR ;
LENTZ, SJ ;
CASTRO, BM ;
CACCHIONE, D ;
CARNEIRO, N .
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 1995, 100 (C2) :2283-2319
[3]   STATISTICAL PROPERTIES OF NEAR-SURFACE FLOW IN THE CALIFORNIA COASTAL TRANSITION ZONE [J].
BRINK, KH ;
BEARDSLEY, RC ;
NIILER, PP ;
ABBOTT, M ;
HUYER, A ;
RAMP, S ;
STANTON, T ;
STUART, D .
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 1991, 96 (C8) :14693-14706
[4]   SEPARATION OF TIDAL AND SUBTIDAL CURRENTS IN SHIP-MOUNTED ACOUSTIC DOPPLER CURRENT PROFILER OBSERVATIONS [J].
CANDELA, J ;
BEARDSLEY, RC ;
LIMEBURNER, R .
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 1992, 97 (C1) :769-788
[6]  
EGLER W. A., 1962, B MUSEU PARAENSE EMI, V1, P2
[7]  
FLAGG CN, 1986, J PHYS OCEANOGR, V16, P1412, DOI 10.1175/1520-0485(1986)016<1412:HACOOT>2.0.CO
[8]  
2
[9]   OBSERVATIONS OF CURRENTS AND WATER PROPERTIES IN THE AMAZON FRONTAL ZONE [J].
GEYER, WR ;
KINEKE, GC .
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 1995, 100 (C2) :2321-2339
[10]  
Geyer WR., 1991, OCEANOGRAPHY, V4, P8, DOI DOI 10.5670/0CEAN0G.1991.15