COVERAGE has assembled and provides unified access to a curated suite of interagency Earth observation data for the oceans that are of broad applicability to the science and applications communities. Satellite datasets included span the range of parameters for the four CEOS “virtual ocean constellations” (VCs): Sea Surface Temperature (SST), Ocean Vector Winds (OVW), Ocean Surface Topography (OST), and Ocean Color Radiometry (OCR). COVERAGE also provides dynamic access to select in-situ biological datasets in support of its thematic demonstration application related to biodiversity within pelagic ecosystems, and provides advanced tools for integrating and overlaying these observations.
The ability for heterogeneous oceanographic datasets to be integrated in this manner and provisioned in analysis ready form hinges on the adoption of geospatial data interoperability standards. COVERAGE leverages widely employed Earth observation data standards, including ISO-19115, the Climate Forecast Conventions (CF), and Attribute Conventions for Data Discovery (ACCD), and associated controlled vocabularies for semantic interoperability (CF standard names, NASA GCMD keywords, ITIS taxonomic serial numbers). In the case of in-situ, COVERAGE is also playing an important role in extending these standards as necessary to provide needed support for biological datasets, including standards for animal telemetry data of different kinds. This ensures alignment of physical and biological oceanographic observations based on a common data interoperability framework.
COVERAGE aggregates and provides simplified, transparent access to a curated set of key satellite datasets from CEOS agencies for a complementary range of ocean variables. These have been reviewed and selected and in consultation with domain experts from the CEOS ocean VCs. For the current COVERAGE prototype, emphasis has been placed on assembling a coherent baseline set of data products that are of high quality and add value to one another consistent with following criteria:
- Providing global, gap free spatial coverage at 0.25 degree resolution that is common across all remotely sensed ocean variables
- Overlapping, multi-year time series available also in near real-time where possible
- Standards compliant file formats and metadata available
- Publicly accessible via standard data access protocols
While initially for the COVERAGE prototype system we focusing on coarser grained satellite datasets commensurate with the needs of the thematic demonstration application as a proof of concept, the underlying technical infrastructure is being designed with higher resolution data in mind.
Project satellite products are complemented by a set of select in-situ datasets in support of the COVERAGE thematic pilot application. These reflect a range of spatial data types of differing complexity:
- Multi-species, monthly spatial catch and effort series from the four tuna Regional Fisheries Management Organizations (RFMOs) over the period 1952- present. This is a unique, long-term dataset documenting the distribution and evolution pelagic fish communities subject to commercial harvesting and environmental forcing across global ocean basin scales.
- Complementary Automatic Identification System (AIS) fishing vessel positional data products available daily from 2012-2018 from our collaborators at Global Fishing Watch.
- Animal telemetry data from collaborating agencies, including IMOS, NOAA/IOOS-ATN, and IATTC, showing extraordinary movements of highly migratory species both horizontally and vertically in response to a dynamical environment.
The inventory review of inter-agency satellite datasets conducted during the initial scoping phase of the COVERAGE project indicated an apparent paucity in the availability of a level 4, gap-free ocean color chlorophyll-A product. To address this given also the importance of this parameter to biological and ecosystem studies, COVERAGE is pursuing the development and validation of a multi-mission, L4 CHL-A product based on the NASA Multi-Resolution Variational Analysis (MRVA) algorithm. Used also in the production of the complementary GHRSST MUR-SST dataset that is part of the COVERAGE collection, MRVA is a meshless, multi-scale interpolation method based on the wavelet transform that is particular adept at preserving spatial features in the data. Information on the validated COVERAGE L4 MRVA CHLA product is available here. Documentation includes the algorithm theoretical basis document (ATBD), validation analysis report, data product format/metadata specification, and access information for dataset evaluation.