Quantifying the ocean velocity contribution to the Alboran Sea primary production

Abstract

This work uses ROMS ocean circulation model coupled with Fennel biochemical model to relate the surface Chlorophyll (Chl) with ocean velocities in the Alboran Sea (Western Mediterranean). The influence of zonal wind on the primary production in the area is documented in previous works. Here we analyze how the wind can affect the Chl through the different ocean velocity components and what spatial and temporal patterns are more important to produce the observed chlorophyll blooms. To carry out such analyses we correlate the ocean velocity components with the chlorophyll concentration coming all from model simulations. The simulations use a grid of 2 km resolution with a climatology in both, meteorological forcing and boundary conditions. First, the spatial and temporal variability of Chl and ocean velocities have been characterized using standard statistics. Second, the original time series are separated in annual cycle and residual, and both are submitted to an EOF computation scheme. Then, the correlations between the amplitudes of the first temporal modes of Chl-velocities couple have been quantified. Using the most correlated pair in the annual cycle and residual we quantify which percentage of Chl biomass production is due to long term (monthly or seasonal) or short-term (days to weeks) ocean velocities