Challenges to Standardization: A Case Study Using Coastal and Deep-Ocean Water Level Data

Abstract:

Sea levels recorded at coastal stations and inferred from deep-ocean pressure observations at the seafloor are submitted for archive in multiple data and metadata formats. These formats include two forms of schema-less XML and a custom binary format accompanied by metadata in a spreadsheet. The authors report on efforts to use existing standards to make this data more discoverable and more useful beyond their initial use in detecting tsunamis. An initial review of data formats for sea level data around the globe revealed heterogeneity in presentation and content. In the absence of a widely-used domain-specific format, we adopted the general model for structuring data and metadata expressed by the Network Common Data Form (netCDF). netCDF has been endorsed by the Open Geospatial Consortium and has the advantages of small size when compared to equivalent plain text representation and provides a standard way of embedding metadata in the same file. We followed the orthogonal time-series profile of the Climate and Forecast discrete sampling geometries as the convention for structuring the data and describing metadata relevant for use. We adhered to the Attribute Convention for Data Discovery for capturing metadata to support user search. Beyond making it possible to structure data and metadata in a standard way, netCDF is supported by multiple software tools in providing programmatic cataloging, access, subsetting, and transformation to other formats. We will describe our successes and failures in adhering to existing standards and provide requirements for either augmenting existing conventions or developing new ones. Some of these enhancements are specific to sea level data, while others are applicable to time-series data in general.