DOI: 10.1007/s00382-012-1514-x
Scopus记录号: 2-s2.0-84868103469
论文题名: The effect of Congo River freshwater discharge on Eastern Equatorial Atlantic climate variability
作者: Materia S. ; Gualdi S. ; Navarra A. ; Terray L.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2012
卷: 39, 期: 2017-09-10 起始页码: 2109
结束页码: 2125
语种: 英语
英文摘要: The surface ocean explains a considerable part of the inter-annual Tropical Atlantic variability. The present work makes use of observational datasets to investigate the effect of freshwater flow on sea surface salinity (SSS) and temperature (SST) in the Gulf of Guinea. In particular, the Congo River discharges a huge amount of freshwater into the ocean, affecting SSS in the Eastern Equatorial Atlantic (EEA) and stratifying the surface layers. The hypothesis is that an excess of river runoff emphasize stratification, influencing the ocean temperature. In fact, our findings show that SSTs in the Gulf of Guinea are warmer in summers following an anomalously high Congo spring discharge. Vice versa, when the river discharges low freshwater, a cold anomaly appears in the Gulf. The response of SST is not linear: temperature anomalies are considerable and long-lasting in the event of large freshwater flow, while in dry years they are less remarkable, although still significant. An excess of freshwater seems able to form a barrier layer, which inhibits vertical mixing and the entrainment of the cold thermocline water into the surface. Other processes may contribute to SST variability, among which the net input of atmospheric freshwater falling over EEA. Likewise the case of continental runoff from Congo River, warm anomalies occur after anomalously rainy seasons and low temperatures follow dry seasons, confirming the effect of freshwater on SST. However, the two sources of freshwater anomaly are not in phase, so that it is possible to split between atypical SST following continental freshwater anomalies and rainfall anomalies. Also, variations in air-sea fluxes can produce heating and cooling of the Gulf of Guinea. Nevertheless, atypical SSTs cannot be ascribed to fluxes, since the temperature variation induced by them is not sufficient to explain the SST anomalies appearing in the Gulf after anomalous peak discharges. The interaction processes between river runoff, sea surface salinity and temperature play an effective role in the interannual variability in the EEA region. Our results add a new source of variability in the area, which was often neglected by previous studies. © 2012 Springer-Verlag. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/55121
Appears in Collections: 过去全球变化的重建
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作者单位: Centro Euro-Mediterraneo per i Cambiamenti Climatici, Bologna, Italy; Istituto Nazionale di Geofisica e Vulcanologia, Bologna, Italy; Sciences de l'Univers au CERFACS, URA1875 CERFACS/CNRS, Toulouse, France
Recommended Citation:
Materia S.,Gualdi S.,Navarra A.,et al. The effect of Congo River freshwater discharge on Eastern Equatorial Atlantic climate variability[J]. Climate Dynamics,2012-01-01,39(2017-09-10)