Observed low frequency variability of the Brazil Current frontстатья из журнала
Аннотация: [1] The Brazil Current is a weak western boundary current, the southwest component of the South Atlantic subtropical gyre, which is the main conduit of upper ocean waters in the region. The objective of this work is to report on observed low frequency variability of the Brazil Current front using satellite-derived sea height anomaly and sea surface temperature observations during the 1993–2008 period. The variability of the front is studied in terms of the separation of the Brazil Current front from the continental shelf break. During the study period, estimates of this parameter vary 6 degrees in latitude, and the mean monthly estimates exhibit a shift to the south of approximately 1.5 degrees. Statistically significant changes are not observed in the geostrophic transport of the Brazil and Malvinas currents, suggesting that the low-frequency changes of the Brazil Current front are governed by different mechanisms than the seasonal variability of these surface currents. Surface drifter trajectories and simulations using synthetic drifters are consistent with the observed shift to the south of the Brazil Current front. Trends of eddy kinetic energy, sea height anomaly, sea surface temperature and wind stress curl are also in agreement with the variability reported here. Wavelet transform analysis revealed interesting changes in the periodicity of the latitude of separation of the Brazil Current front from the continental shelf break, with periods ranging from semiannual to biannual. Longer records, together with comprehensive numerical experiments, will ultimately be needed to determine the origin of these changes.
Год издания: 2011
Авторы: Gustavo Goñi, Francis Bringas, Pedro DiNezio
Издательство: American Geophysical Union
Источник: Journal of Geophysical Research Atmospheres
Ключевые слова: Oceanographic and Atmospheric Processes, Ocean Waves and Remote Sensing, Climate variability and models
Открытый доступ: bronze
Том: 116
Выпуск: C10