The synergy of water quality and sea surface currents data in determining the spatio-temporal evolution of large-scale circulation features

Abstract

Chlorophyll-a (CHL-a) and Sea Surface Temperature (SST), amongst others, are proxies or indicators for water quality and can be easily retrieved synoptically and almost in near-real time through satellite remote-sensing. However, as they evolve in space and time in response to winds and currents, a full resolution of the temporal and spatial scales of these latters is required and their influence in shaping the distribution of water quality parameters needs to be assessed. While providing synoptic views and revealing mesoscale features, satellites suffer, indeed, from inadequate representation of sub-grid physical processes and lack of temporal resolution. Conventional point-wise measurements provide data to study high-frequency motions such as tides or high-frequency wind-driven circulation, lacking on the other hand of the spatial resolution required to resolve their spatial variability. We show here that a combined use of near-surface currents, available through High-Frequency (HF) radars, and satellite data (e.g., TERRA and AQUA/MODIS, VIIRS/NPP), are complementary tools as they help solving both fine-scale structures, especially at the coastal boundaries where satellite imageries lack of the required resolution, as well as satellite-derived mesoscale structures are fundamental aid to understand and interpret finer-scale structures in terms of larger-scale ocean dynamics.