Zonal structure of the mean flow and eddies in the Azores Current system
| Autor: | A. Cordeiro Pires, B. Le Cann, Álvaro Peliz, A.C. Barbosa Aguiar |
|---|---|
| Přispěvatelé: | Centro de Oceanografia, Universidade de Lisboa (ULISBOA), Centro de Estudos do Ambiante e do Mar (CESAM), Universidade de Aveiro, Laboratoire de physique des océans (LPO), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
Atmospheric Science
010504 meteorology & atmospheric sciences Seamount Soil Science Aquatic Science Oceanography 01 natural sciences 010305 fluids & plasmas Geochemistry and Petrology 0103 physical sciences Earth and Planetary Sciences (miscellaneous) Mean flow 14. Life underwater [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography 0105 earth and related environmental sciences Earth-Surface Processes Water Science and Technology Azores High geography geography.geographical_feature_category Ecology Paleontology Forestry Geophysics Eddy 13. Climate action Space and Planetary Science Anticyclone Ridge Climatology Outflow Longitude Geology |
| Zdroj: | Journal of Geophysical Research. Oceans Journal of Geophysical Research. Oceans, Wiley-Blackwell, 2011, 116, pp.C02012. ⟨10.1029/2010JC006538⟩ Repositório Científico de Acesso Aberto de Portugal Repositório Científico de Acesso Aberto de Portugal (RCAAP) instacron:RCAAP |
| ISSN: | 2169-9275 2169-9291 |
| DOI: | 10.1029/2010JC006538⟩ |
| Popis: | International audience; The surface circulation and eddy field from the Azores Current system are studied here by analyzing surface drifters records and altimetry maps collected over more than 16 years. Clear differences in mean flow and eddy characteristics allow for a classification of the Azores Current in three zonal sectors: west of 30°W between the Mid‐Atlantic Ridge and the Hyères‐Atlantis seamount system, between 30°W and the longitude of Madeira, and east of Madeira. A detailed and quantitative characterization of each sector is given. The transition between the western and central parts is controlled by the Hyères‐Atlantis ridge. In the transition to the eastern sector there is a change in the dynamics and the flow is forced by the cyclonic recirculation driven by the Mediterranean outflow. There is no clear expression of a continuous surface northern counterflow, but three distinct westward flows are seen: one along the southeastern border of the Azores plateau, another one southwest of Madeira, and a third one along 31°N west of the Hyères seamount. No clear tilt in the axis of the Azores Current is found in the calculated mean surface flow from surface drifters. Observations from both drifters and altimetry data show that anticyclonic features dominate in the northern region, whereas cyclonic ones dominate in the southern region. Overall, cyclones are more numerous, constituting 60% of large eddies. The eddy features detected in the west tend to be larger than those in the east, both in size and sea level anomaly. There is indication of different mean propagation speeds east and west of 25°W-30°W, with the mean speeds consistently increasing by 25%-45% in the west. Estimates for the rate of formation of strong eddies range from 1.4 to 2.4 year−1 for cyclones, and 1.2 to 1.7 year−1 for anticyclones. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|