TIDE-INDUCED MIXING IN THE AMAZON FRONTAL ZONE

被引:61
作者
GEYER, WR [1 ]
机构
[1] WOODS HOLE OCEANOG INST, WOODS HOLE, MA 02543 USA
关键词
D O I
10.1029/94JC02543
中图分类号
P7 [海洋学];
学科分类号
0707 ;
摘要
The freshwater discharge from the Amazon River produces a bottom salinity front on the Amazon shelf that extends many hundreds of kilometers along the shelf, between the 10- and 20-m isobaths. Strong cross-shelf tidal currents cause advective excursions of the front of more than 20 km and supply the major source of kinetic energy for mixing on the shelf. This mixing is manifested in spring-neap variations in the frontal structure and position, with weaker stratification and seaward migration of the front during periods of strong tidal currents, and stronger stratification and landward migration during neap tides. Mixing appears to be driven by shear instability, based on local estimates of gradient Richardson number and bulk estimates of the water column stability. Maximum mixing occurs during ebb, when vertical shear is greatest. Suspended sediment reaches such high concentrations in the frontal zone that it makes a significant contribution to the stratification, thus increasing the stability of the flow and reducing the effectiveness of tide-induced mixing.
引用
收藏
页码:2341 / 2353
页数:13
相关论文
共 51 条
[1]   THE HYDRAULICS OF 2 FLOWING LAYERS WITH DIFFERENT DENSITIES [J].
ARMI, L .
JOURNAL OF FLUID MECHANICS, 1986, 163 :27-58
[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]   GRAVITY CURRENTS AND RELATED PHENOMENA [J].
BENJAMIN, TB .
JOURNAL OF FLUID MECHANICS, 1968, 31 :209-&
[4]  
BUSINGER JA, 1971, J ATMOS SCI, V28, P181, DOI 10.1175/1520-0469(1971)028<0181:FPRITA>2.0.CO
[5]  
2
[6]   VORTICITY CONCENTRATION AND DYNAMICS OF UNSTABLE FREE SHEAR LAYERS [J].
CORCOS, GM ;
SHERMAN, FS .
JOURNAL OF FLUID MECHANICS, 1976, 73 (JAN27) :241-264
[7]   SILL PROCESSES RELATED TO DEEP-WATER RENEWAL IN A FJORD [J].
GEYER, WR ;
CANNON, GA .
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 1982, 87 (NC10) :7985-7996
[8]  
GEYER WR, 1987, J PHYS OCEANOGR, V17, P1668, DOI 10.1175/1520-0485(1987)017<1668:SIIAHS>2.0.CO
[9]  
2
[10]   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