A cloud based brokering framework to support hydrology at global scale

This work presents the hydrology broker designed and deployed in the context of a collaboration between the Regional Agency for Environmental Protection in the Italian region Emilia-Romagna (ARPA-ER) and CNR-IIA (National Research Council of Italy). The hydrology brokering platform eases the task of discovering and accessing hydrological observation data, usually acquired and made available by national agencies by means of a set of heterogeneous services (e.g. CUAHSI HIS servers, OGC services, FTP servers) and formats (e.g. WaterML, O&M, ...). The hydrology broker makes all the already published data available according to one or more of the desired and well known discovery protocols, access protocols, and formats . As a result, the user is able to search and access the available hydrological data through his preferred client (e.g. CUAHSI HydroDesktop, 52North SWE client). It is also easy to build a hydrological web portal on top of the broker, using the user friendly js API. The hydrology broker has been deployed on the Amazon cloud to ensure scalability and tested in the context of the work of the Commission for Hydrology of WMO on three different scenarios: the La Plata river basin, the Sava river basin and the Arctic-HYCOS project. In each scenario the hydrology broker discovered and accessed heterogeneous data formats (e.g. Waterml 1.0/2.0, proprietary CSV documents) from the heterogeneous services (e.g. CUAHSI HIS servers, FTP service and agency proprietary services) managed by several national agencies and international commissions. The hydrology broker made possible to present all the available data uniformly through the user desired service type and format (e.g. an HIS server publishing Waterml 2.0), producing a great improvement in both system interoperability and data exchange. Interoperability tests were also successfully conducted with WMO Information System (WIS) nodes, making possible for a specific Global Information Center System (GISC) to gather the available hydrological records as ISO 19115:2007 metadata documents through the OAI-PMH interface exposed by the broker. The framework flexibility makes it also easy to add other sources, as well as additional published interfaces, in order to cope with the future standard requirements needed by the hydrological community.