WMO Hydrological Observing System (WHOS) broker: implementation progress and outcomes

Abstract

<p>The WMO Hydrological Observing System (WHOS) is a service-oriented System of Systems (SoS) linking hydrological data providers and users by enabling harmonized and real time discovery and access functionalities at global, regional, national and local scale. WHOS is being realized through a coordinated and collaborative effort amongst:</p><ul><li>National Hydrological Services (NHS) willing to publish their data to the benefit of a larger audience,</li> <li>Hydrologists, decision makers, app and portal authors willing to gain access to world-wide hydrological data,</li> <li>ESSI-Lab of CNR-IIA responsible for the WHOS broker component: a software framework in charge of enabling interoperability amongst the distributed heterogeneous systems belonging to data providers (e.g. data publishing services) and data consumers (e.g. web portals, libraries and apps),</li> <li>WMO Commission of Hydrology (CHy) providing guidance to WMO Member countries in operational hydrology, including capacity building, NHSs engagement and coordination of WHOS implementation.</li> </ul><p>In the last years two additional WMO regional programmes have been targeted to benefit from WHOS, operating as successful applications for others to follow:</p><ul><li>Plata river basin,</li> <li>Arctic-HYCOS.</li> </ul><p>Each programme operates with a “view” of the whole WHOS, a virtual subset composed only by the data sources that are relevant to its context.</p><p><strong>WHOS-Plata</strong> is currently brokering data sources from the following countries:</p><ul><li>Argentina (hydrological & meteorological data),</li> <li>Bolivia (meteorological data; hydrological data expected in the near future),</li> <li>Brazil (hydrological & meteorological data),</li> <li>Paraguay (meteorological data; hydrological data in process),</li> <li>Uruguay (hydrological & meteorological data).</li> </ul><p><strong>WHOS-Arctic</strong> is currently brokering data sources from the following countries:</p><ul><li>Canada (historical and real time data),</li> <li>Denmark (historical data),</li> <li>Finland (historical and real time data),</li> <li>Iceland (historical and real time data),</li> <li>Norway (historical and real time data),</li> <li>Russian (historical and real time data),</li> <li>United States (historical and real time data).</li> </ul><p>Each data source publishes its data online according to specific hydrological service protocols and/or APIs (e.g. CUAHSI HydroServer, USGS Water Services, FTP, SOAP, REST API, OData, WAF, OGC SOS, …). Each service protocol and API in turn implies support for a specific metadata and data model (e.g. WaterML, CSV, XML , JSON, USGS RDB, ZRXP, Observations & Measurements, …).</p><p>WHOS broker implements mediation and harmonization of all these heterogeneous standards, in order to seamlessly support discovery and access of all the available data to a growing set of data consumer systems (applications and libraries) without any implementation effort for them:</p><ul><li>52North Helgoland (through SOS v.2.0.0),</li> <li>CUAHSI HydroDesktop (through CUAHSI WaterOneFlow),</li> <li>National Water Institute of Argentina (INA) node.js WaterML client (through CUAHSI WaterOneFlow),</li> <li>DAB JS API (through DAB REST API),</li> <li>USGS GWIS JS API plotting library (through RDB service),</li> <li>R scripts (through R WaterML library),</li> <li>C# applications (through CUAHSI WaterOneFlow),</li> <li>UCAR jOAI (through OAI-PMH/WIGOS metadata).</li> </ul><p>In particular, the support of WIGOS metadata standard provides a set of observational metadata elements for the effective interpretation of observational data internationally.</p><p>In addition to metadata and data model heterogeneity, WHOS needs to tackle also semantics heterogeneity. WHOS broker makes use of a hydrology ontology (made available as a SPARQL endpoint) to augment WHOS discovery capabilities (e.g. to obtain translation of a hydrology search parameter in multiple languages).</p><p>Technical documentation to exercise WHOS broker is already online available, while the official public launch with a dedicated WMO WHOS web portal is expected shortly.</p>

Water Data Explorer: An Open-Source Web Application and Python Library for Water Resources Data Discovery

“…The CUAHSI HIS uses a community-controlled shared vocabulary for hydrologic terms [24] and defined formal protocols for communication between system components, including WaterOneFlow web services and the WaterML data transfer encoding protocol [25,26]. The CUAHSI HIS includes, at present, 97 registered data servers sharing time series data for 1,222,585 sites around the globe and a total of 10,353,663,916 data values [27]. CUAHSI HIS protocols have been implemented by other data providers and software systems including the WHOS data broker [28].The CUAHSI HIS project [5,12,13] was an early leader in the area of water resources SOA cyberinfrastructure.…”

“…WHOS is a services-oriented framework linking hydrological data and users through an information system that provides data registration, data discovery, and data access [29,30]. WHOS supports the publication of customized data subsets using the concept of "views" to provide data capabilities to various organizations and users [31].…”

“…For example, a "basin view" can contain all the data sets that are collected and shared by neighboring countries in a specific basin. Client components built by others can access the WHOS views for data discovery, download and visualization using WaterOneFlow web services.WHOS is a services-oriented framework linking hydrological data and users through an information system that provides data registration, data discovery, and data access [28,29] WHOS supports the publication of customized data subsets using the concept of "views" to provide data capabilities to various organizations and users [30]. For example, a "basin view" can contain all the data sets in a specific basin that are collected and shared by neighboring countries.…”

HESS Opinions: Participatory Digital Earth Twin Hydrology systems (DARTHs) for everyone: a blueprint for hydrologists

“…A recent conference contribution (Boldrini et al, 2020) vice); R scripts (through R WaterML library); C# applications (through CUAHSI WaterOneFlow); and UCAR jOAI (through OAI-PMH/WIGOS metadata). At present, both in research and in applications, the action of matching data and models is done off-line by the researchers, but the DARTH vision would require that these data be automatically ingested and processed.…”

The Grids Python Tool for Querying Spatiotemporal Multidimensional Water Data

“…One such standard is the Observations Data Model (ODM) which is an SQL database schema for sharing point data and metadata [8]. The Consortium of Universities for the Advancement of Hydrologic Sciences Inc (CUAHSI), the Open Geospatial Consortium (OGC), and the World Meteorological Organization (WMO) have produced a series of coding packages, web apps, data services and standards, and other kinds of software which build on the ODM schema and common standards [8][9][10][11].…”