Characterisation of candidate OC-SVC sites - El Hierro

EUMETSAT manages the operations of Ocean Colour products derived from the Ocean and Land Colour Imager (OLCI) instrument flown on the Sentinel-3 satellites from the European Commission Copernicus Programme. Ocean Colour System Vicarious Calibration (OC-SVC) with radiometric measurements at sea is required to achieve the quality of the Ocean Colour products defined in the mission requirements. OC-SVC requires a dedicated infrastructure at a favourable location. EUMETSAT has initiated activities on behalf of the EC to investigate the Copernicus OC-SVC infrastructure.

This study is part of a survey to find the best location for potential Copernicus OC-SVC infrastructure in European waters in terms of atmospheric, oceanographic and logistical site characteristics. The study follows Phase-1 and Phase-2 activities of the Copernicus OC-SVC roadmap and precedes the proposed Phase-4 activity. Phase-1 and Phase-2 were respectively the Scientific, Technical and Operational Requirements, and the Preliminary Design, Project Plan and Costing. The proposed Phase-4 is the Technical Definition, Specification, and Detailed Design study.

This study climatologically characterised the El Hierro in the Canaries (Spain) in terms of multiple atmospheric, oceanographic, logistical and other relevant parameters, in order to assess its suitability for the Copernicus OC-SVC infrastructure.

El Hierro location: 27.5876N, 18.1573W

Objectives

The objective of the study was to gather environmental data from available datasets and process them to provide a climatological characterisation of the El Hierro site and its surroundings.

In particular, geographic, atmospheric, oceanographic and anthropic conditions were assessed and analysed with respect to the requirements set in Phase-1, for the selection of an appropriate site to operate the field segment of an OC-SVC infrastructure. The study also included a description of the logistics envisioned to support the development and operations of the future Copernicus OC-SVC infrastructure, in case the site would be selected.

Overview

El Hierro island is the second-smallest and the farthest south and west island of the Canary Archipelago, with a long Marine Reserve and with 60% of its inland territory protected to preserve its natural and cultural diversity as an UNESCO Biosphere Reserve.

Every single requirement established in the Statement of Work (SoW) to determine the feasibility of an OC-CSV site has been successfully satisfied at the El Hierro site, double checking its validity through different databases that are consistent with each other. The El Hierro OC-SVC site enjoys high stability of subtropical atmosphere isolated from local and regional anthropogenic pollution contributions, with high light availability, high persistence of cloud-free conditions, low surface wind, and stable and spatially uniform maritime aerosols through most of the year. Moreover, from the oceanic point of view, the El Hierro OC-SVC site has well-mixed calm, clear, and stable ocean waters with no shear in the first 20m, minimal maritime traffic, and a very safe location close to a marine reserve.

The IEO-AEMET consortium provides a team of technicians and researches highly experienced in operational and scientific aspects of the region's atmosphere and ocean, as well as nearby ports, storage, and maintenance facilities to ensure proper long-term maintenance of heavy oceanographic equipment at the El Hierro OC-SVC site. El Hierro island has a high volume data communication system by optical fibre.

Data sources

The analysis also included additional site-specific data.