کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4538451 1626514 2006 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Seasonal and inter-annual variability of chlorophyll-a concentration in the Mauritanian upwelling: Observation of an anomalous event during 1998–1999
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات زمین شناسی
پیش نمایش صفحه اول مقاله
Seasonal and inter-annual variability of chlorophyll-a concentration in the Mauritanian upwelling: Observation of an anomalous event during 1998–1999
چکیده انگلیسی

Monthly chlorophyll-a (Chl-a) concentrations derived from SeaWiFS data for 1997–2005 and chlorophyll measurements from the Atlantic Meridional Transect for 1995–2001 have been analysed to describe seasonal and inter-annual variability of surface Chl-a in the Mauritanian upwelling. There was a moderate to strong correspondence between the seasonal cycles of surface Chl-a and the seasonal cycles of ocean physical and meteorological fields (such as sea-surface temperature, sea-surface height, and prevailing wind), with a noticeable exception in 1998 that corresponded to a strong anomalous Chl-a event (∼250% increase) in the Mauritanian upwelling. Alongshore wind-stress and wind-stress curl were found to be the most significant factors controlling the variability of Chl-a (jointly explaining more than 50% of total variance). The biological response to the alongshore wind-stress was immediate, but it lagged the wind-stress curl by 1–2 months (each explaining more than 40% of the total Chl-a variability). These observations also demonstrate a link, hitherto unreported, between the Pacific El-Niño Southern Oscillation (ENSO) and anomalous Chl-a field in the Mauritanian upwelling. The multivariate ENSO index was shown to account for a significant part of the variability of the autumn–winter Chl-a anomaly (r=−0.52, p<0.01). A cold event, following an intense El Niño in the Pacific during summer, was found to mirror the intensity of wind forcing and phytoplankton concentration in the Mauritanian upwelling a few months later. Therefore, ENSO-related changes in the local atmospheric fields are considered as the preferred candidates for explaining the observed biological changes in the Mauritanian upwelling during 1998–1999.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Deep Sea Research Part II: Topical Studies in Oceanography - Volume 53, Issues 14–16, July–August 2006, Pages 1548–1559
نویسندگان
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