Recent trends in plankton and upwelling intensity off Galicia (NW Spain)

Bode, Antonio; Alvarez-Ossorio, M. T.; Cabanas, José Manuel Oro; Miranda, A.; Varela, Manuel

doi:10.1016/j.pocean.2009.07.025

Cited by 77 publications

(56 citation statements)

References 22 publications

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“…Both results confirm previous independent observational findings in the NW (Bode et al, 2009) and in the SW (Relvas et al, 2009). These results, however, do not contradict Bakun (1990), where an intensification of the main upwelling systems is found in response to global warming, but indicate that regional features in those systems may respond in different directions, imposing extra complexity.…”

Section: Discussionsupporting

confidence: 93%

“…10), and corroborate results of previous studies, indicating a decreasing of upwelling during the last decades at the northern western Iberian coast (e.g. Bode et al, 2009) and increasing of upwelling at its southern limit (Santos et al, 2005;Relvas et al, 2009). Furthermore, the ROMS ' ERA-Interim results also indicate that the changes in coastal SST are related with upwelling, since they are accompanied by consistent changes in the sea surface height and in the horizontal currents (not shown).…”

Section: Trends In Simulated Upwelling Frequencysupporting

confidence: 91%

“…Some studies suggested a weakening in coastal upwelling intensity in the northern limit of western Iberia (e.g. Bode et al, 2009), or even along all the western Iberian coast , while others suggested increasing upwelling in the south sector of western Iberia (Santos et al, 2005;Relvas et al, 2009). …”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Variability of Iberian upwelling implied by ERA-40 and ERA-Interim reanalyses

Alves

Miranda

2013

Tellus A: Dynamic Meteorology and Oceanography

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A B S T R A C T The Regional Ocean Modeling System ocean model is used to simulate the decadal evolution of the regional waters in offshore Iberia in response to atmospheric fields given by ECMWF ERA-40 (1961Á2001) and ERAInterim (1989Á2008) reanalyses. The simulated sea surface temperature (SST) fields are verified against satellite AVHRR SST, and they are analysed to characterise the variability and trends of coastal upwelling in the region. Opposing trends in upwelling frequency are found at the northern limit, where upwelling has been decreasing in recent decades, and at its southern edge, where there is some evidence of increased upwelling. These results confirm previous observational studies and, more importantly, indicate that observed SST trends are not only due to changes in radiative or atmospheric heat fluxes alone but also due to changes in upwelling dynamics, suggesting that such a process may be relevant in climate change scenarios.

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Section: Discussionsupporting

confidence: 93%

Section: Trends In Simulated Upwelling Frequencysupporting

confidence: 91%

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Variability of Iberian upwelling implied by ERA-40 and ERA-Interim reanalyses

Alves

Miranda

2013

Tellus A: Dynamic Meteorology and Oceanography

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“…Aristegui et al, 2009). Bode et al (2009) observed a continuous decrease in upwelling intensity in the northern CC around the Canary Islands during the past 40 years, associated with the warming of surface waters, a decrease in zooplankton abundance, and, locally, in phytoplankton abundance. Studying a sediment core off Cape Ghir, Morocco, a cooling of the northern Canary Current in the 20th century was inferred (McGregor et al, 2007).…”

Section: Introductionmentioning

confidence: 98%

Deep ocean mass fluxes in the coastal upwelling off Mauritania from 1988 to 2012: variability on seasonal to decadal timescales

Fischer¹,

Romero²,

Merkel³

et al. 2016

Biogeosciences

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Abstract. A more than two-decadal sediment trap record from the Eastern Boundary Upwelling Ecosystem (EBUE) off Cape Blanc, Mauritania, is analysed with respect to deep ocean mass fluxes, flux components and their variability on seasonal to decadal timescales. The total mass flux revealed interannual fluctuations which were superimposed by fluctuations on decadal timescales. High winter fluxes of biogenic silica (BSi), used as a measure of marine production (mostly by diatoms) largely correspond to a positive North Atlantic Oscillation (NAO) index (December-March). However, this relationship is weak. The highest positive BSi anomaly was in winter 2004-2005 when the NAO was in a neutral state. More episodic BSi sedimentation events occurred in several summer seasons between 2001 and 2005, when the previous winter NAO was neutral or even negative. We suggest that distinct dust outbreaks and deposition in the surface ocean in winter and occasionally in summer/autumn enhanced particle sedimentation and carbon export on short timescales via the ballasting effect. Episodic perturbations of the marine carbon cycle by dust outbreaks (e.g. in 2005) might have weakened the relationships between fluxes and largescale climatic oscillations. As phytoplankton biomass is high throughout the year, any dry (in winter) or wet (in summer) deposition of fine-grained dust particles is assumed to enhance the efficiency of the biological pump by incorporating dust into dense and fast settling organic-rich aggregates. A good correspondence between BSi and dust fluxes was observed for the dusty year 2005, following a period of rather dry conditions in the Sahara/Sahel region. Large changes of all bulk fluxes occurred during the strongest El Niño-Southern Oscillation (ENSO) in 1997-1999 where low fluxes were obtained for almost 1 year during the warm El Niño and high fluxes in the following cold La Niña phase. For decadal timescales, Bakun (1990) suggested an intensification of coastal upwelling due to increased winds ("Bakun upwelling intensification hypothesis"; Cropper et al., 2014) and global climate change. We did not observe an increase of any flux component off Cape Blanc during the past 2 and a half decades which might support this. Furthermore, fluxes of mineral dust did not show any positive or negative trends over time which might suggest enhanced desertification or "Saharan greening" during the last few decades.

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“…In spite of several studies on the upwelling regime off the west coast of the Iberian Peninsula (see e.g. Fiuza et al, 1982;Peliz et al, 2002;Capet et al, 2004;Bode et al, 2009), there has been no detailed study concerning the wind regime that gives rise to this ocean response.…”

Section: Introductionmentioning

confidence: 99%

Climatology of the Iberia coastal low-level wind jet: weather research forecasting model high-resolution results

Soares

Cardoso²,

Semedo

et al. 2014

Tellus A: Dynamic Meteorology and Oceanography

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A B S T R A C T Coastal low-level jets (CLLJ) are a low-tropospheric wind feature driven by the pressure gradient produced by a sharp contrast between high temperatures over land and lower temperatures over the sea. This contrast between the cold ocean and the warm land in the summer is intensified by the impact of the coastal parallel winds on the ocean generating upwelling currents, sharpening the temperature gradient close to the coast and giving rise to strong baroclinic structures at the coast. During summertime, the Iberian Peninsula is often under the effect of the Azores High and of a thermal low pressure system inland, leading to a seasonal wind, in the west coast, called the Nortada (northerly wind). This study presents a regional climatology of the CLLJ off the west coast of the Iberian Peninsula, based on a 9 km resolution downscaling dataset, produced using the Weather Research and Forecasting (WRF) mesoscale model, forced by 19 years of ERA-Interim reanalysis (1989Á2007). The simulation results show that the jet hourly frequency of occurrence in the summer is above 30% and decreases to about 10% during spring and autumn. The monthly frequencies of occurrence can reach higher values, around 40% in summer months, and reveal large inter-annual variability in all three seasons. In the summer, at a daily base, the CLLJ is present in almost 70% of the days. The CLLJ wind direction is mostly from north-northeasterly and occurs more persistently in three areas where the interaction of the jet flow with local capes and headlands is more pronounced. The coastal jets in this area occur at heights between 300 and 400 m, and its speed has a mean around 15 m/s, reaching maximum speeds of 25 m/s.

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Recent trends in plankton and upwelling intensity off Galicia (NW Spain)

Cited by 77 publications

References 22 publications

Variability of Iberian upwelling implied by ERA-40 and ERA-Interim reanalyses

Variability of Iberian upwelling implied by ERA-40 and ERA-Interim reanalyses

Deep ocean mass fluxes in the coastal upwelling off Mauritania from 1988 to 2012: variability on seasonal to decadal timescales

Climatology of the Iberia coastal low-level wind jet: weather research forecasting model high-resolution results

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