Recorded presentation9A.5
Innovation at the Royal Netherlands Meteorological Institute (KNMI); web technologies for every day use by the forecaster
Marcel Molendijk, KNMI, De Bilt, Netherlands
As a result of a mayor innovation programme at KNMI, several important tools for the forecaster have been renewed. All of these applications are now web based; a mayor shift from the existing standalone applications.
Three of these applications are presented in more detail.
RADAR presentation system – RADIS 5
Monitoring precipitation is one of the key issues in nowcasting at the Royal Netherlands meteorological institute (KNMI). A dedicated presentation system has been developed to display real time precipitation and derived products like echo top height, sort of precipitation, short time forecast and wind shear. External sources as lightning and station observations are added. The system is equipped with alert and warning functions in case of severe weather.
The design of the RADAR display is based on a thin client animation engine that communicates to a server side client that captures, prepares and archives data. This architecture entails a web based system that can be tailored for different users inside (intranet) and outside (extranet) KNMI with respect to data access and permitted features. For example, in case of extreme server load during severe weather, irrelevant options like detailed roadmaps can be remotely disabled to conserve network bandwidth.
On the server side data is accumulated and stored in HDF5 Data Format in a platform independent and self-contained way. Storage of actual data builds up an online archive for several days, directly accessible to users. After conversion to bitmap and XML format, data is sent to the client by an HTTP internet protocol.
On the user side a Java Web Start application is equipped with advanced animation functionality and mouse-over features. The animation engine stacks multiple layers of data and maps, each of which can be turned on and off independently. The stack of layers allows maps and data layers to be updated anytime. Maps can be static or can be imported from a GIS mapping server. Warnings pop up when severe weather conditions are nowcasted. These include lightning alerts, summer hail warning and warnings for exceeding thresholds of accumulative precipitation in areas of interest set by the user.
The forecast of precipitation (0-2 h) is obtained by extrapolation and interpolation using clustering techniques, feature tracking and pattern recognition. Wind fields are incorporated from high resolution NWP. Short time forecast is a highly demanded feature of our clients to extrapolate the actual conditions and recognize extreme weather phenomena.
Web based production system - producteditor
At KNMI approximately 30 different weather forecasts and 25 different weather warnings are produced by forecasters. Almost all of these forecasts are text messages, more or less specific for general, aviation and maritime meteorology. The forecasts are now produced on 10 different systems, putting constraints not only on maintenance but also on scalability. A new production system, the producteditor, was developed with the use of different web technologies.
Heart of the system is a IBM Lotus web-formserver with a digital product form repository. The forecasters logs in on the server by a browser and his working schedule is shown. On the schedule, links to product forms are provided and the forecaster may open, edit and send the product form to the formserver. The product form itself consists of XFDL, the content (the data put in by the forecaster) is XML. Product generation is done by stylesheets. For maintenance (adding, removing product forms, changing working schedules, etc) a separate maintenance interface is developed.
Standard functionality for each product form consists of o.a. text field validation, product preview, input of automatic produced data, input of earlier produced forecasts. For warnings and alerts, valid periods and update time are presented graphically.
Forecasters are now able to produce text-based forecasts from any place, as long as they are connected to internet. There is no need for separate configuration, since all the information send to and form the formserver is HTML.
Web based Meteorological working system - pilot
Just like many other meteorological institutes in the world, KNMI is in the process of obtaining a new meteorological working system for forecasters. To support the decision on whether or not aiming for a web based system, a pilot was conducted to asess the feasibility of building a web browser based system for display of operational meteorological data.
Several existing visualisation tools have been fitted with a simple subset of an OGC Web Mapping Service interface. The outputs of these WMS services (graphical representations of meteorological data) are then combined in a browser window by means of the OpenLayers JavaScript library, which provides layering, panning and zooming functionality and some handling for data time functionality. The resulting browser application can display numerical model output fields, radar and satellite imagery and has limited functionality for drawing additional features like lines or polygons on top of the images.
For the visualisation of model fields the ECMWF Magics++ library is used. For the visualisation of satellite imagery the CineSat (by Gepard, Austria) system is used. A custom WMS interface analyzes the WMS request and uses CineSat reprojection commands to generate the satellite layer(s).
Radar imagery is being served by an existing WMS service developed by KNMI based on the Minnesota MapServer.
The resulting browser application looks very promising. Although the system is by no means a complete meteorological workstation, the chosen techniques make development of such a system feasible. make development of such a system feasible.
Session 9A, Interactive Processing Systems II
Wednesday, 14 January 2009, 10:30 AM-11:30 AM, Room 121BC
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