An improved coastal upwelling index from sea surface temperature using satellite-based approach – The case of the Canary Current upwelling system

Benazzouz, Aïssa; Mordane, Soumia; Orbi, A.; Chagdali, Mohamed; Hilmi, Karim; Atillah, Abderrahman; Pelegrí, Josep Lluís; Demarcq, Hervé

doi:10.1016/j.csr.2014.03.012

Cited by 132 publications

(121 citation statements)

References 28 publications

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“…No such explanation helps to understand the JanuaryFebruary transition for which we simply note that it is associated with the most significant month-to-month V QK direction shift (Figure 4a). As it allows one to locate where the upwelling signal is the most intense, the zonal position of the SST minima is an important quantity [Benazzouz et al, 2014]. It is shown in Figure 7 as monthly averages throughout the upwelling season (October-May).…”

Section: Ssuc Seasonal Patternmentioning

confidence: 99%

SST patterns and dynamics of the southern Senegal‐Gambia upwelling center

et al. 2014

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The southern end of the Canary current system comprises of an original upwelling center that has so far received little attention, the Southern Senegal-Gambia Upwelling Center (SSUC). We investigate its dynamical functioning by taking advantage of favorable conditions in terms of limited cloud coverage. Analyses and careful examinations of over 1500 satellite images of sea surface temperature scenes contextualized with respect to wind conditions confirm the regularity and stability of the SSUC dynamical functioning (as manifested by the recurrence and persistence of particular SST patterns). The analyses also reveal subtle aspects of its upwelling structure: shelf break cooling of surface waters consistent with internal tide breaking/mixing; complex interplay between local upwelling and the Mauritanian current off the Cape Verde headland; complexity of the inner-shelf/mid shelf frontal transition. The amplitude of the diurnal cycle suggests that large uncertainties exist in the SSUC heat budget. The studies limitations underscore the need for continuous in situ measurement in the SSUC, particularly of winds.

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Section: Ssuc Seasonal Patternmentioning

confidence: 99%

SST patterns and dynamics of the southern Senegal‐Gambia upwelling center

et al. 2014

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“…They only found a significant correlation between UI W and NAO, but not with UI SST . Similarly, Benazzouz et al (2014) and Narayan et al (2010) concluded that a significant correlation was absent between UI SST and NAO. This could mean that, although UI SST is a qualitatively acceptable index to characterize upwelling intensity (as suggested by Cropper et al, 2014), it lacks the ability to fully describe upwelling variability, perhaps due to its intrinsic simplicity and vulnerability to suffer variations caused by factors unrelated to upwelling (e.g., open ocean warming episodes).…”

Section: Variability Associated With Climate Modesmentioning

confidence: 99%

Trends in Primary Production in the Canary Current Upwelling System—A Regional Perspective Comparing Remote Sensing Models

et al. 2017

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After Bakun (1990) formulated his hypothesis of upwelling intensification caused by increasing global warming, contradictory results have been published on whether primary productivity is increasing or decreasing in Eastern Boundary Upwelling Ecosystems (EBUE). The present work is focused in comparing three net primary production (NPP) models-the VGPM (Vertically Generalized Production Model), the Eppley-VGPM and the CbPM (Carbon-based Production Model)-in the Canary Current (CanC) EBUE during the 1998-2015 period, making use of both SeaWiFS (Sea-viewing Wide Field-of-view Sensor) and MODIS (MODerate-resolution Imaging Spectroradiometer) derived data. We looked for the first time for seasonal to interannual trends of NPP under a regional perspective, with the aim of searching for temporal patterns that could support or reject the intensification hypothesis. According to previous studies based on the seasonality of the upwelling regime, the CanC EBUE was divided into three subregions: a seasonal upwelling zone (SUZ; 13-20 • N), a permanent upwelling zone (PUZ; 20-26 • N) and a weak permanent upwelling zone (WPUZ; 26-33 • N). Although differences in the output of the models are important, both at regional and subregional scales, our analyses do not show significant increasing trends in NPP with any of the productivity models used. Our results are in accordance with previous published studies that indicate, that unlike other EBUE, winds have weakened (or at least not intensified) in the CanC upwelling over time scales ranging up to 60 years. Nevertheless, the comparison made in this work shows disagreements between some of the best-known NPP models and calls for a validation effort in this region. Seasonal to decadal anomalies of NPP and sea-surface temperature (SST) are estimated and analyzed in relation to selected climate indices, yielding only significant correlations between SST and the North Atlantic Oscillation (NAO) indices.

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“…The study was carried out in the southern area of the Moroccan Atlantic coast, namely between cape Blanc and cape Boujdor which is a subject of permanent upwelling (Makaoui et al, 2005;Benazzouz et al, 2014). The presence of upwelling provides this zone with high productivity (primary and secondary production) which is variable in time and space (Berraho, 2007).…”

Section: Discussionmentioning

confidence: 99%

“…The southern area, between Cap Blanc and Cap Boujdor (21°-26°30′N) ( Fig.1) is an area of a permanent upwelling (Makaoui et al, 2005;Benazzouz et al, 2014). In fact, in the north of Dakhla the upwelling activity is permanent but weaker in autumn; while in the region of Cap Blanc, in addition to the upwelling phenomenon, it is the seat of a thermal front infl uenced by the NACW (North Atlantic Central Water) and SACW (South Atlantic Central Water) (Makaoui et al, 2005).…”

Section: Introductionmentioning

confidence: 99%

Autumn larval fish assemblages in the northwest African Atlantic coastal zone

Abdelouahab

Berraho

Baibai

et al. 2016

Chin. J. Ocean. Limnol.

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A study on the assemblage composition and vertical distribution of larval fi sh was conducted in the southern area of the Moroccan Atlantic coast in Autumn 2011. A total of 1 680 fi sh larvae taxa were identifi ed from 21 families. The majority of the larvae were present in the upper layers. Clupeids were the most abundant larvae taxa followed by Myctophidae, Gadidae and Sparidae, hence the larval fi sh assemblages (LFA) were variable in diff erent depth layers. Total fi sh larvae showed a preference for surface layers, and were mainly found above 75 m depth, with some exceptions. The maximum concentration of fi sh larvae was concentrated up to 25 m essentially above the thermocline, where chlorophyll a and mesozooplankton were abundant. Spatially, neritic families were located near the coast and at some off shore stations especially in the northern part, while oceanic families were more distributed towards off shore along the study area. Cluster analysis showed a segregation of two groups of larvae. However, a clear separation between neritic families and oceanic families was not found. Multivariate analysis highlighted the relationship between the distribution of larvae of diff erent families and environmental parameters. Temperature and salinity seem to have been the factors that acted on associations of fi sh larvae. Day/night vertical distributions suggest there was not a very signifi cant vertical migration, probably due to adequate light levels for feeding.

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An improved coastal upwelling index from sea surface temperature using satellite-based approach – The case of the Canary Current upwelling system

Cited by 132 publications

References 28 publications

SST patterns and dynamics of the southern Senegal‐Gambia upwelling center

SST patterns and dynamics of the southern Senegal‐Gambia upwelling center

Trends in Primary Production in the Canary Current Upwelling System—A Regional Perspective Comparing Remote Sensing Models

Autumn larval fish assemblages in the northwest African Atlantic coastal zone

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