Local versus remote wind effects on the coastal circulation of a microtidal bay in the Mediterranean Sea

被引:23
作者
Jordi, Antoni [1 ]
Basterretxea, Gotzon [1 ]
Wang, Dong-Ping [2 ]
机构
[1] IMEDEA UIB CSIC, Inst Mediterrani Estudis Avancats, Esporles 07190, Illes Balears, Spain
[2] SUNY Stony Brook, Sch Marine & Atmospher Sci, Stony Brook, NY 11794 USA
关键词
Coastal circulation; Wind-driven currents; Island trapped waves; Bays; Mediterranean Sea; TRAPPED WAVES; POSIDONIA-OCEANICA; EDDY FORMATION; MALLORCA; CURRENTS; ISLAND; SHELF; DYNAMICS; BREEZE; SPAIN;
D O I
10.1016/j.jmarsys.2011.05.007
中图分类号
P [天文学、地球科学];
学科分类号
07 ;
摘要
Coastal currents in microtidal bays are assumed to be weak and random, promptly responding to variations in wind forcing. However wind effects can act at scales that vary from local to large scales. With the aim of examining the response of coastal flow to local and regional wind forcing and their relative importance as drivers of coastal circulation, current data were collected during five months during the summer 2009 in Palma Bay (western Mediterranean Sea). The data set is jointly analyzed with a primitive-equation model to characterize the circulation in the bay. Moored acoustic Doppler current profiler (ADCP) data shows that currents in the bay fluctuate widely in direction resulting in an almost negligible mean current (<1.5 cm/s). This strong variability is mainly attributed to two major wind forced mechanisms interacting in the bay: island trapped waves (ITWs) propagating at an island scale and locally wind-induced mass balance. Wind forced oscillations at periods of 60 and 24 h dominate current variability. The fluctuations at 60 h are associated with the first radial and first azimuthal mode of ITWs generated by remote wind. Weak ITWs are associated with currents flowing parallel to the coast, whereas more intense ITWs form an anticyclonic gyre over the southeastern part of the bay due to flow separation at Enderrocat Cape. At the period of 24 h, the wind has two effects: the first radial and second azimuthal mode of ITWs and a local wind-induced mass balance in response to the sea breeze. Variations in wind and consequent changes in coastal circulation are a major contributor to coastal water renewal, and hence critically influence key environmental aspects such as water quality or marine organism dispersal in Palma Bay. (C) 2011 Elsevier B.V. All rights reserved.
引用
收藏
页码:312 / 322
页数:11
相关论文
共 44 条
[1]  
[Anonymous], 1970, Nature, V227, P1037, DOI [DOI 10.1038/2271037A0, 10.1038/2271037a0]
[2]   Modulation of nearshore harmful algal blooms by in situ growth rate and water renewal [J].
Basterretxea, G. ;
Garces, E. ;
Jordi, A. ;
Angles, S. ;
Maso, M. .
MARINE ECOLOGY PROGRESS SERIES, 2007, 352 :53-65
[3]   Breeze conditions as a favoring mechanism of Alexandrium taylori blooms at a Mediterranean beach [J].
Basterretxea, G ;
Garcés, E ;
Jordi, A ;
Masó, M ;
Tintoré, J .
ESTUARINE COASTAL AND SHELF SCIENCE, 2005, 62 (1-2) :1-12
[4]   Seasonal dynamics of a microtidal pocket beach with Posidonia oceanica seabeds (Mallorca, Spain) [J].
Basterretxea, G ;
Orfila, A ;
Jordi, A ;
Casas, B ;
Lynett, P ;
Liu, PLF ;
Duarte, CM ;
Tintoré, J .
JOURNAL OF COASTAL RESEARCH, 2004, 20 (04) :1155-1164
[5]  
BRETHERTON CS, 1992, J CLIMATE, V5, P541, DOI 10.1175/1520-0442(1992)005<0541:AIOMFF>2.0.CO
[6]  
2
[7]  
BRINK KH, 1991, ANNU REV FLUID MECH, V23, P389, DOI 10.1146/annurev.fl.23.010191.002133
[8]   Island-trapped waves, with application to observations off Bermuda [J].
Brink, KH .
DYNAMICS OF ATMOSPHERES AND OCEANS, 1999, 29 (2-4) :93-118
[9]  
DAVIES PA, 1995, J COASTAL RES, V11, P154
[10]  
Echevin V, 2003, J PHYS OCEANOGR, V33, P188, DOI 10.1175/1520-0485(2003)033<0188:IOACCW>2.0.CO