by John L. Guiney*
New communication networks and forecast system innovations and technology (e.g. Internet, wireless communication, digital database forecasting, next-generation workstations, nowcasting systems) have emerged, which provide the opportunity to improve public weather services (PWS). These innovations allow National Meteorological and Hydrometeorological Services (NMHSs) to provide hydrometeorological forecasts and warnings in a variety of formats (graphic, digital) beyond the traditional text products. In addition, these innovations can impact NMHS service delivery capabilities. Digital database forecasting and next-generation workstations, along with new and emerging Information Technology (IT) systems and applications, offer the opportunity to further enhance and integrate PWS dissemination and service delivery functions.
This article provides an overview of several key innovations, technological advancements and IT systems/applications which have, or can have, a substantial impact on improving NMHSs’ public weather services and their dissemination and service delivery. It will focus on digital database forecasting, next-generation forecast workstations, nowcasting systems and IT systems and applications.
Digital database forecasting
The traditional forecast process employed by most NMHSs involves forecasters producing text-based, sensible, weather-element forecast products (e.g. maximum/minimum temperature, cloud cover) using numerical weather prediction (NWP) output as guidance. The process is typically schedule-driven, product-oriented and labour-intensive. Over the last decade, technological advances and scientific breakthroughs have allowed NMHSs’ hydrometeorological forecasts and warnings to become much more specific and accurate.
As computer technology and high-speed dissemination systems evolved (e.g. Internet), National Weather Service (NWS) customers/partners were demanding detailed forecasts in gridded, digital and graphic formats. Traditional NWS text forecast products limit the amount of additional information that can be conveyed to the user community. The concept of digital database forecasting provides the capability to meet customer/partner demands for more accurate, detailed hydrometeorological forecasts. Digital database forecasting also offers one of the most exciting opportunities to integrate PWS forecast dissemination and service delivery, which most effectively serves the user community.
Both the US National Oceanic and Atmospheric Administration (NOAA)/National Weather Service and Environment Canada are currently using digital database forecasting technology to produce routine forecasts. The Australian Bureau of Meteorology is in the process of evaluating and developing an implementation plan for database forecasting using the NOAA/NWS National Digital Forecast Database approach.
Environment Canada National Weather Element Database
Environment Canada has developed the National Weather Element Forecast Database (NWEFD) that is populated with output from NWP models. Environment Canada forecasters manipulate the NWEFD making adjustments to forecast fields based on an analysis of the current state of the atmosphere and model output, including known model biases and trends. When complete, the forecaster runs software that creates text-based forecasts. To assist in the development and population of NWEFD, Environment Canada has developed an expert system called SCRIBE.
SCRIBE is capable of automatically or interactively generating a wide array of weather products for a region or a specific locality. The system uses data from a set of matrices which are generated after the 00Z and 12Z NWP model runs. These matrices contain different types of weather elements, including NWP output, statistical guidance model output (Perfect Prog (PP) and Updatable Model Output Statistics (UMOS) models) and climatological data.
SCRIBE’s temporal resolution is three hours. SCRIBE produces forecasts twice daily for 1 145 Canadian station locations. When ready, the matrices are sent to each regional SCRIBE system. Upon arrival, the data are processed by the concept generator and are synthesized and downsized to a set of well-defined weather elements called “concepts”. These concepts are output in a digitally coded format called METEOCODE and can be displayed on a graphic interface. Forecasters can modify the concept output to incorporate the latest observations, as well as the evolving weather scenario/event. The concepts are used by the regional offices to generate local forecast products. They are also sent to NWEFD, where a suite of national forecast products are generated. Figure 1 shows the main steps in the SCRIBE data processing.
||Figure 1 — Flow chart depicting the primary steps in the SCRIBE data processing (Landry, C. et al., 2005)|
NOAA/NWS National Digital Forecast Database
In the 1990s, the NOAA/NWS recognized that it had to develop its hydrometeorological products and services beyond text-based forecasts to meet growing customer/partner demands. In 2003, NWS launched the National Digital Forecast Database (NDFD). The NDFD is an event-driven, information-oriented, interactive and collaborative hydrometeorological forecast database. The NDFD consists of a seven-day forecast for a set of 14 sensible weather elements on a 5-km domain which covers the contiguous USA, Alaska, Guam, Hawaii and Puerto Rico (see table, below). In some locations, the database resolution varies from 1.25 to 2.5 km, primarily in areas of significant terrain. Each of the 122 NWS Weather Forecast Offices produces and maintains the database for its area of responsibility. Figure 2 shows examples of NDFD output graphics.
|Figure 2 — Examples of NDFD output graphics: (a) regional dewpoint graphic; (b) local wind-speed and direction graphic|
Using the latest observations, radar and satellite data, guidance products from the National Centers for Environmental Prediction (NCEPs), and NWP output, forecasters interactively modify the database using the Gridded Forecast Editor. Several NCEPs also contribute forecast information to the NDFD, including probabilistic hazard and climate outlook information (see table, below). NWS forecast text, tabular and graphic products are generated directly from the database using product formatters and other output-defined software.
The database itself is provided as an NWS product to customers and partners. This allows users to access it for their own applications, manipulate it and extract forecast information tailored to their specific needs. In the years ahead, NWS will continue to work toward developing NDFD as a complete four-dimensional environmental database. Future NDFD expansion will include observations, analyses, aviation-specific elements, additional climate information, uncertainty/probabilistic information, outlooks, watches and warnings.
|Status of NWS NDFD elements as of October 2007
(click for enlargement)
Next-generation forecast workstations
Continuing advances in IT and communication capabilities suggest that the rapid increase in the volume of hydrometeorological data during the last three decades will continue and may even accelerate in the years ahead. The proliferation of automated observing systems and mesonetworks, coupled with improvements and/or replacements of existing remote-sensing observing systems, portend at least an order-of-magnitude increase in data.
The next-generation forecast workstations will need more bandwidth, storage capacity, and processing power to handle the expected rapid increase of data, along with increased temporal and spatial resolution NWP model output. This makes it imperative that the next-generation forecast workstations are equipped with new, state-of-the-art visualization and information-processing techniques, including three-dimensional techniques, to assist forecasters with data analysis and interpretation.
Sophisticated diagnostic tools will also be required to examine the data and highlight meteorological processes. In addition, the large volume of data will require increased reliance on advanced algorithms and processing techniques to monitor both current and forecast conditions, extract and portray the most relevant information, and assist with hydrometeorological decision support. The next-generation forecast workstations will assist in the preparation of forecasts and warnings and their dissemination through a host of communication channels/networks. These workstations will also have the capability to support digital database forecast preparation.
Some next-generation workstations may also look to incorporate an Internet-based instant messenger chat (IMChat) capability to allow NMHSs to communicate with key customers and partners during significant hydrometeorological events and all-hazards incidents. The NWS is currently experimenting with the IMChat concept in significant hydrometeorological operations. (IMChat is an Internet chatroom-type of connection with key customers and partners to obtain critical information in real-time for an unfolding time-sensitive event or incident.) In turn, NMHSs would receive site-specific reports and other information which can assist with forecast and warning operations.
A number of NMHSs have been developing innovative, next-generation nowcast systems. Nowcast systems range in complexity; some track radar echoes and use extrapolation to produce 0-to 1-hour nowcasts, while more complex systems utilize a combination of NWP output and probabilistic/uncertainty forecast techniques to extend the nowcasting time horizon out to 3-6 hours. Some of these systems also incorporate other remote-sensing platforms, including satellite and lightning data. Many of these systems are still challenged to optimize the role of the forecaster in the nowcasting process.
One of the other key focus areas is incorporating real-time verification and feedback to forecasters. An important strength of a nowcast system is its ability to rapidly generate hydrometeorological forecast products and disseminate them in a variety of formats. This capability will have significant implications for timely and effective PWS service delivery.
Several forecast demonstration projects have been organized through WMO to test nowcasting systems and applications. The first demonstration project was successfully carried out in 2000 at the Summer Olympic Games in Sydney, Australia. Another demonstration project was conducted during the 2008 Summer Olympics in Beijing, China.
Information technology systems and applications
Since its inception, NMHSs have exploited the Internet to varying degrees. While almost all NMHSs have an Internet Web page, the dissemination and services provided vary considerably.
The Internet allows NMHSs to present hydrometeorological forecasts and warnings and climate information to customers, partners and the public in graphic and digital formats that would otherwise be unavailable. It also provides opportunities to enhance and expand service delivery. For example, Environment Canada has developed an Internet Website exclusively for the media which allows them to tailor data to their specific needs. In another example, NWS implemented an aviation-focused initiative called the Collaborative Convective Forecast Product in partnership with its aviation community. The initiative was based on an assessment which showed that weather-related delays due to convective activity are the single most disruptive force within US national airspace.
The expansion of the Internet in the 1990s, coupled with new computer and telecommunication technologies, led to a proliferation of IT systems and applications. The evolution of PWS dissemination/service delivery integration is directly linked to the emergence of new computer and telecommunication technologies and information systems (e.g. the Internet, wireless communication technologies, geographic information systems (GIS), Global Positioning System (GPS), mobile communication networks). These innovations allow NMHSs to provide weather forecasts and warnings in a variety of new formats (digital, XML, CAP) to meet customer demands for more precise and accurate environmental information. In addition, these new and emerging technologies offer the opportunity to further integrate PWS dissemination and service delivery functions. Other evolving capabilities (PodCasts/VodCasts) can also enhance PWS service delivery.
Geographic information systems and the Global Positioning System
Geographic information systems are designed for capturing, storing, analysing and managing data and associated attributes which are spatially referenced to the Earth. The Global Positioning System, originally developed in the 1970s by the USA for military applications, became available for civilian use in the 1980s. It is comprised of 24 Earth-orbiting satellites which provides location-specific information as precise as tens of metres. Together, GIS and GPS provide a powerful technological tool for NMHSs to enhance their PWS service delivery. By utilizing GIS and GPS with mobile communications networks and devices (cell phones, PDAs), NMHSs can effectively deliver user-and location-specific warnings and forecasts.
The NWS is utilizing GIS technology in its short-fused hydrometeorological warning programme through the implementation of storm-based warnings (also referred to as polygon warnings). Currently, four types of short-fused warnings (tornado, severe thunderstorm, flash flood, and special marine) include polygon information which takes the form of latitude and longitude pairs and highlights the threatened area (Figure 3).
Figure 3 — Sample severe weather warning with latitude and longitude pairs (highlighted at the end of the warning) which can be utilized by GIS applications
Data from these warnings are collected and databased into a real-time set of GIS shapefiles. These files can be downloaded from the NWS Website in real-time and used by customers and partners in other GIS applications. GIS and GPS users include emergency managers/planners and media partners. Emergency managers and the media can quickly access and download GIS shapefiles via the Internet, add them to their existing GIS fields and incorporate them into other GIS applications.
Extensible Mark-up Language
Extensible Mark-up Language (XML) is an Internet-based language format for documents containing structured information or data. An Internet mark-up language is a mechanism to identify structures in a document. The XML specification defines a standard way to add mark-up to documents. Structured information contains both content (words, pictures, etc.) and some indication of what role that content plays (e.g. content in a section heading has a different meaning from content in a footnote, which means something different from content in a figure caption or in a database table). XML is designed to describe data/information and the document tags are user-defined. XML is a cross-platform, software-and hardware-independent tool for transmitting data and information. It is important to emphasize that XML complements HyperText Mark-up Language (HTML) and is not a replacement for HTML. XML is designed to describe data/information, while HTML is designed to format and display data/information.
Another benefit of XML is its ability to exchange data between incompatible systems. In many instances, computer systems and databases contain data in incompatible formats. One of the most time-consuming challenges has been the exchange of data between such systems over the Internet. Converting data to XML format can greatly reduce this complexity and create data that can be read by a wide array of applications.
Common Alerting Protocol
The Common Alerting Protocol (CAP) is an open, non-proprietary standard data-interchange format that can be used to collect all-hazard warnings and reports locally, regionally and nationally for input into a wide range of information-management and warning-dissemination systems. CAP format uses XML and standardizes the content of alerts and notifications across all hazards, including hazardous material incidents, severe weather, fires, earthquakes and tsunamis. CAP’s origins can be traced back to recommendations of the “Effective disaster warnings” report issued in November 2000 by the US Working Group on Natural Disaster Information Systems, Subcommittee on Natural Disaster Reduction.
Systems using CAP have shown that a single authoritative and secure alert message can quickly launch Internet messages, news feeds, television text captions/scrolls, highway sign messages, and synthesized voice-over automated telephone calls or radio broadcasts to effectively alert the public. CAP is a simple but general format for exchanging all-hazard emergency alerts and public warnings, including hydrometeorological warnings, over a wide variety of communication networks. CAP allows a consistent warning message to be disseminated simultaneously over many different systems, thus increasing its effectiveness while simplifying the warning dissemination task. CAP provides a template for effective warning messages based on best practices identified in academic research and real-world experience. Growing segments of the emergency management community are embracing CAP as a comprehensive, all-in-one approach to provide critical all-hazard information to the public.
In turn, the NWS is working towards adopting the CAP standard. Figure 4 shows both the raw CAP code and an example of how CAP is used in real-time from the California Office of Emergency Services.
|Figure 4 — (a) NWS raw CAP code and real-time application from the California Office of Emergency Services; (b) text in red corresponds to highlighted text in (a).|
Real Simple Syndication
XML is driving a host of new, innovative communication capabilities that can enhance PWS service delivery. This includes Real Simple Syndication (RSS). RSS is a family of Web formats used to share, distribute and publish frequently updated digital content. RSS is commonly used to update news articles and other content that changes quickly. Typically, RSS feeds deliver text and graphic content; however, they may also include audio files (PodCasts) or even video files (VodCasts).
RSS is a pull-focused approach to receiving environmental information. Rather than the traditional approach of NMHSs “pushing” hydrometeorological products to its customers and partners, users install RSS readers which allow them to select and tailor the environmental information they need to meet their specific needs. Users subscribe to a feed by entering the link of the RSS feed into their RSS reader; the RSS reader then checks the subscribed feeds for new content on a recurring basis. If new content is detected, the reader retrieves the new information and provides it to the user. Most standard Internet web browsers (Firefox, Internet Explorer 7, Mozilla, Safari) can read RSS feeds automatically. Alternatively, users can install a stand-alone RSS feed reader or news aggregator.
Thus, RSS gives the user the ability to maintain awareness of the environmental situation and quickly obtain the latest hydrometeorological information from their NMHS as needed. This approach has the added benefit of reducing the load on NMHS Web servers during significant high-impact hydrometeorological events and other high-traffic periods. Figure 5 shows the United Kingdom Met Office RSS instruction Web page describing how users can access RSS feeds for their products and the NOAA/NWS Internet site with links to available RSS feeds.
|(a) UK Met Office||(b) NOAA|
Figure 5 — Information on hydrometeorological RSS feeds from (a) the United Kingdom Met Office describing how users can access RSS feeds for its products; (b) NOAA/NWS Internet site with links to available RSS feeds.
Keyhole Mark-up Language
Keyhole Mark-up Language (KML) is a recent XML-based offshoot designed for geospatial data applications. More specifically, KML is an XML-based language and file format for describing three-dimensional geospatial data and its display in application programs. KML has a tag-based structure similar to HTML, with names and attributes used for specific display purposes.
KML can be used to store geographic features such as points, lines, images, polygons and models for display in Google Earth and Google Maps. A KML file is processed by Google Earth and Google Maps in a way similar to that in which HTML and XML files are processed by Web browsers. NMHSs may be able to exploit features of KML to add another dimension to delivering user and location specific warnings and forecasts.
One of the most exciting and innovative future technology enhancements for PWS is in the radar remote-sensing arena. Next-generation radar systems (dual-polarization radar, phased-array radar) provide the opportunity to improve severe weather detection, rainfall estimates and winter weather warnings and increase the lead time for severe weather hazards, including tornadoes and heavy rain/flash flood events.
Dual-polarization radars transmit radio-wave pulses that have both horizontal and vertical orientations. The additional information from vertical pulses will greatly improve forecasts and warnings for a variety of hazardous weather, including severe weather, heavy rainfall and winter weather events. Unlike current WSR-88D radars (which transmit one beam of energy at a time, listen for the returned energy, then mechanically tilt in elevation and sample another small section of the atmosphere), a phased-array radar system uses multiple beams, sent out at one time, so the antennas never need to tilt. This results in a complete scan of the entire atmosphere in about 30 seconds, compared to 6-7 minutes for the WSR-88D radar. In addition, the phased-array radar system incorporates the dual-polarization radar capabilities.
The benefits of phased-array radars for public weather services are broad and significant. They will allow NMHSs to issue improved and more timely warnings of severe weather hazards, including the potential to issue graphic formatted tornado warnings up to 30 minutes or more in advance and improve the lead time for flash flood warnings and icing forecasts for aviation interests.
The emergence of new, innovative and technologically advanced forecast systems and communication networks provide a host of exciting possibilities for NMHSs to improve their public weather services and effectively integrate dissemination and service delivery. NMHS PWS dissemination and delivery will be dictated in large part by the development and application of these systems. Digital database forecasting offers one of the most fascinating opportunities to integrate PWS forecast dissemination and delivery most effectively to NMHS customers, partners and the general public. While it is recognized that digital forecasting is in its formative stages and new telecommunication technologies are still emerging, NMHSs should keep abreast of this evolving forecasting approach.
Next-generation forecast workstations bring the promise of new methods to assimilate vast amounts of observational data and NWP output, including new visualization and information-processing techniques, to assist forecasters with data analysis and interpretation. These workstations will assist with forecast preparation and significant event, high-impact hydrometeorological decision support. In addition, these workstations will likely incorporate sophisticated nowcasting systems which will integrate an array of real-time data and NWP output to provide prognostic information out to six hours, while also helping to rapidly generate and disseminate forecast products.
Information technology systems and associated applications, including XML, CAP and RSS, will allow NMHSs to exploit the latest telecommunication networks, including broadband, wireless and mobile systems, to improve their public weather services. Coupled with GIS and GPS capabilities, NMHSs can satisfy customer and partner demands for ever-increasing precision, accuracy and detailed, location-specific hydrometeorological forecasts and warnings.
Together, these efforts will allow NMHSs to cultivate an innovative and effective PWS programme which leverages technological advances to create a holistic forecast and warning dissemination, service delivery and all-hazard decision support process that best serves their user communities.
* Chief, Meteorological Services Division, US National Oceanic and Atmospheric Administration/National Weather Service Eastern Region, Bohemia, New York USA 11716