C. Troupin, P. Sangrà, and J. Arístegui (2010)
Seasonal variability of the oceanic upper layer and its modulation of biological cycles in the Canary Island region
Journal of Marine Systems, 80(3-4):172-183.
The Canary Island region is rich in mesoscale phenomena that affect cycles of physical and biological processes. A 1D version of the Regional Oceanic Modeling System (ROMS) is used south of the Gran Canaria Island to simulate seasonal climatologies of these cycles. The model is forced with monthly air-sea fluxes averaged from 1993 to 2002 and initialized with mean in situ profiles of temperature, salinity, oxygen and nitrate concentrations. The K-Profile Parameterization (KPP) mixed layer submodel is compared with other submodels using idealized numerical experiments. When forced with realistic air-sea fluxes, the model correctly reproduces the annual cycle of temperature (mixed layer depth), with minimum surface values of 18 °C (maximal depth 105 m) in February during convective mixing resulting from a negative heat flux. Maximum temperatures above 23 °C (minimal depth 20 m) are simulated from September to October after strong summer heating and a decrease in Trade Winds intensity. A simple ecosystem model is coupled to the physical model, which provides simulated biological cycles that are in agreement with regional observations. A phytoplankton bloom develops in late winter, driven by the injection of new nutrients into the euphotic layer. Simulated chlorophyll shows a deep maximum fluctuating around 100 m with concentrations around 1 mg Chla m- 3, while surface values are low (around 0.1 mg Chla m- 3 ) during most of the year. The physical and biological model results are validated by comparisons with data from regional studies, climatological fields and time-series from the ESTOC station.
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