Seasonal and interannual variability of surface circulation in the Cape Verde region from 8 years of merged T/P and ERS-2 altimeter data
Seasonal and interannual variability of surface circulation in the Cape Verde region from 8 years of merged T/P and ERS-2 altimeter data
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DOI：
10.1016/j.rse.2005.06.005
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发表时间：
2005-09
影响因子：
13.5
通讯作者：
C. Lázaro;M. Fernandes;A. Miguel P. Santos;P. Oliveira
中科院分区：
文献类型：
--
作者：
C. Lázaro;M. Fernandes;A. Miguel P. Santos;P. Oliveira
本文用卫星高度计资料分析了大西洋东北部佛得角群岛地转表面流场的特征。目的是分析3° ~ 30 ° N、40° ~ 10 ° W区域的主要海流系统及其季节和年际变化。使用了Topex/Poseidon（T/P）和ERS-2高度计数据的合并数据集，从1995年6月开始，为期8年，并通过应用一套同类的有关地球物理校正计算了校正的海面高度。ERS-2数据按T/P交叉调整。制作了整个期间的海平面异常月图，并用于计算绝对动态地形、地转流和涡动动能月图。热带大西洋东北部大尺度表面环流的季节性信号似乎是该区域变化的主要原因，特别是在所研究区域的最南端。这种信号也出现在沿着非洲海岸和几内亚穹的流场中。EKE值最高的地区显然与北赤道逆流和沿着非洲海岸的电流有关。1998年的显著年际变化似乎与1997-1998年的ENSO太平洋事件有关，但其他与ENSO无关的异常时期（1996-1997年和2001-2002年）也很明显。
The characterisation of the geostrophic surface flow field around the Cape Verde Archipelago in the northeast Atlantic Ocean with satellite altimeter data is presented. The aim is to analyse the main current systems present in the region 3°–30°N, 40°–10°W and their seasonal and interannual variability. A merged data set of Topex/Poseidon (T/P) and ERS-2 altimeter data for an 8-year period, beginning in June 1995, has been used and corrected sea surface heights were computed by applying a homogeneous set of relevant geophysical corrections. ERS-2 data were crossover adjusted to T/P. Monthly maps of sea level anomalies were created for the whole period and were used in the computation of monthly maps of absolute dynamic topography, geostrophic currents and eddy kinetic energy (EKE). The seasonal signal of the northeast Tropical Atlantic large-scale surface circulation appears as the prevailing cause of the variability in the region, particularly in the southernmost portion of the region being studied. This signal is also present in the flow field along the African coast and in the Guinea Dome. Regions of highest EKE values are clearly associated with the North Equatorial Counter-Current and with the currents along the African coast. The significant interannual variability found for 1998 seems to be associated with the 1997–1998 ENSO Pacific event, but other anomalous periods (1996–1997 and 2001–2002) uncorrelated with ENSO are also evident.