Significant Radiosonde Order from Met Service Canada

Transcription

1 Significant Radiosonde Order from Met Service Canada V aisala has received a major order from the Meteorological Service of Canada. The order follows up on a similar delivery agreement made in According to the agreement, Vaisala will supply Canada s nationwide upper air observation network with radiosondes from 2000 to The contract also includes radiosonde station deliveries and maintenance services. In addition to the radiosonde order, Vaisala has been able to introduce other products to Meteorological Service of Canada. The North American markets are an area of substantial potential for Vaisala. For the next three years, Vaisala will provide 33 upper air observation stations, with the required radiosondes, to the Meteorological Service of Canada. The order also includes additional radiosonde stations and updates. Vaisala will supply Canada s nationwide upper air observation network with radiosondes from 2000 to V Mika Salkola, M.Sc. (Eng.), Aapo Koski, M.Sc. (Eng.), Marika Svennas, M.Sc. (Eng.) and Jukka Valle, B.Sc. (Met..) Upper Air Division Vaisala Helsinki Finland aisala has been actively involved in the development of upper air sounding systems since Several generations of Vaisala radiosounding ground equipment are currently in use worldwide. The fast development of technology enables Vaisala to renew its ground equipment continuously, applying the latest solutions to challenging customer requirements. 1. Challenges for next generation sounding systems User needs vary a lot, depending on the application. Because of the need to save costs, many customers want systems that are easy to use, so that operators can perform soundings with little need for training. On the other hand, certain customer segments, especially the research community, want more flexibility and openness in their systems. 1.1 Connectivity The ability to connect with several types of networks is a feature that is taken for granted in state-of-the-art sounding systems. In addition to facilitating data transmission and distribution, it should be possible, with the increasing level of system automation, to control several systems from one central location. Network connections /2001

2 Vaisala s Next Generation Radiosounding Ground Equipment allow remote software updates so that the customer can always benefit from the latest product features and use the most upto-date versions. On the other hand, network connections set totally new requirements for security and system integrity. Sufficient protection must be provided in order to prevent inadvertent or hostile access to the networked sounding system. 1.2 Cost of labor The cost of labor is an important driver for radiosounding development. The system should enable the usage of part time operators. The sounding preparations should be sufficiently simple to allow them to be done without need for extensive training and detailed system understanding. Operator prompts and local instructions should be available in the operator s native language. A sufficient level of automation should be installed to enable genuine release-and-forget functioning. Furthermore, it should be possible to hand over system control to a remote location after balloon launch. connection through a network will enable system health monitoring and software updates from other locations. Human errors can be reduced by using simplified user interfaces and operating procedures. A simulation capability should be provided to allow analysis of data validity, the optimization of processing parameters and the training of operators without any need to launch a balloon. 1.4 Configurability In order to facilitate product configuration, the radiosounding system should be designed so that most of its components are directly applicable to all customer segments. In general, this means that the system should be highly scalable and capable of fulfilling the requirements set by both synoptic and research users. In order to hide features considered unnecessary by certain user segments, a sufficient level of configurability should be designed into the system. This is of utmost importance for the simplest operating procedures. 1.5 Compatibility 2. The DigiCORA III approach and practical aspects 2.1 Standard operating system The Microsoft Windows NT 4.0 / 2000 Terminal Server Edition was selected as the sounding software platform for DigiCORA III. Its proven stability, robust high-performance multi-tasking, native 32-bit code and extremely versatile communications alternatives were the main reasons. For the user, the availability of localized versions of Windows NT facilitates operation of the sounding system. A wide range of other off-theshelf applications is also available for Windows NT. Networking In addition to providing serial connection, dial-up networking and various LAN protocols (TCP/IP, SPX/IPX, NetBEUI), Windows NT can create networks that scale from the local to the global level. All measured data and meteorological messages can be sent forward by using Windows NT s networking capabilities. Security Windows NT offers built-in C2-level file security. A single workstation can have multiple users, each with complete security and privacy using their own profiles and preferences. 1.3 Reliability To achieve a high rate of data availability, the system should be sufficiently robust and fault tolerant. The product structure should allow simple and fast maintenance, and units should be easily replaceable. Remote Downwards compatibility with the existing operational system components should be maintained as much as possible. All the main windfinding methods from Loran-C and GPS to the Radio Direction Finder should be covered, as well as compatibility with existing radiosondes. Figure 1. The DigiCORA III sounding system configuration includes a workstation running the system software, a sounding processing subsystem and the required antennas. 155/

3 From the left: Aapo Koski, Mika Salkola, Jukka Valle and Marika Svennas. Remote use The possibility of remote operation and maintenance with the Windows NT Terminal Server Edition brings indispensable flexibility. 2.2 Open data management A commercial database engine, Microsoft JET, was selected as the basis of the data management system. MS JET is a widely used MS Office component and thus its data archives can be accessed using standard MS Office tools like Excel or Access. Each sounding produces an extensive range of data, including several kinds of raw data, filtered data, parameters and messages. All the data from one sounding is archived in a single database file. To ensure real-time sounding performance, memory-mapped run-time data storage is needed between the data producers and the data archiving procedure. The link between the runtime data storage and the data archive is bi-directional and reversible. Run-time data can be regenerated from a data archive to perform an analysis or a simulation of a sounding. 2.3 Flexible system architecture A client/server software architecture was selected due to its flexibility. This architecture is based on software modules communicating on a messaging basis, which means that they are loosely coupled. This enables modification of a module without affecting the rest of the system, and allows the introduction of new functions by simply installing new modules. The client/server architecture also makes workload sharing possible by distributing individual modules to other processors connected to the same communication domain. 2.4 Configurable user interface Layered structure A layered User Interface (UI) architecture structure has been applied. The visible topmost layer is very thin and is the only part that is dependent on the operating system. It is on top of a faceless layer where all the UI functions and logic are implemented. For each component in the visible layer there is a corresponding faceless counterpart. The system can be easily adapted to the needs of different operating environments merely by changing the visible layer of the UI. Other visible UI alternatives could be a simple textbased console or an Internetaware browser application. Dynamic modules The user interface framework provides a basic platform that enables dynamic installation of specialized UI modules, each of which is dedicated to some specific purpose and might be connected to specific data. They are used to control the system, or to visualize and utilize the measured data. The UI modules can be easily installed and removed without any software changes. Different users The UI behavior and outlook can be configured for different user needs by changing the user options and privileges. A sounding operator needs only a simple control view, while an advanced researcher needs several visualization and analysis tools and access to all possible data. All users can store their own preferences regarding the UI visual outlook. A system administrator can specify access rights for each user. Resource database User Interface language translation and other forms of localization are simplified by locating all the UI resources in a system external data repository. The translation can be done without any software changes at the end-user s site by local support organizations or users. The database management system used for UI resources /2001

4 such as text, pictures and voices is the same as that used for the archived sounding data. This makes the system architecture very coherent. 2.5 Utilization of subsystems The sounding processing subsystem connected to a new sounding workstation can be any existing Vaisala system with ARCNET networking capabilities in order to offer a planned upgrade path. These subsystems are MW11, MW12, MW15 or RT20A radiotheodolite. Utilization of these subsystems was one main design basis for the DigiCORA III. The sounding system is compatible with all of the Vaisala RS80 and RS90 radiosondes operating at a frequency of 400 MHz or 1680 MHz. 3. Implementation 3.1 DigiCORA III system description The DigiCORA III sounding system shown in Figure 1 has two main components a sounding workstation which contains the DigiCORA III software and stores the sounding data, and a sounding processing subsystem with measuring processor boards which receive and preprocess the data. The data is sent by the individual measuring processor boards to the sounding workstation, where the sounding software collects, analyses, presents and stores the data. The workstation is able to generate and relay meteorological messages through a variety of available connections. The DigiCORA III sounding system can be used in a variety of environments to meet the diverse requirements of users. The basic solution measures pressure, temperature and humidity (PTU). Several options are available for wind finding, including GPS, Loran-C and Radio Direction Finding. Special measurements, such as ozone and radioactivity, can also be incorporated. 3.2 System architecture The applications required to access and manipulate data bene- fit from the client/server architecture. In the client/server solution, a client application acts as data consumer to an intelligent data producer, the server. The client applications do not define where the data is stored, or how it is fetched and managed, nor do they perform lowlevel data manipulation. Instead, the client communicates its data need to the server at an abstract level and the server performs the bulk of the data processing. The following server processes handle most of the sounding process: The database server, which receives messages from clients and passes all the message data to a database driver by calling it. The data returned by the driver is then sent back to clients. All the database engine specific operations are in the driver, which is built on top of a commercial database engine. The connection to any other database engine can be obtained simply by modifying the driver. The data server process which supports real-time data handling and delivery. The sounding controller process which handles general sounding control logic and functions. The user control process (UCP) which is the platform for user interface modules. The sounding computation processes, e.g. the GPS calculation, which consumes raw data from the GPS processing board and the sounding program, which starts the PTU-computation threads and provides calculated data for other processes. The message coding processes The message triggering and distributing processes The implemented client/server architecture allows several monitoring and system controlling clients to be connected simultaneously to one sounding station. Error handling and recovery: All operations during sounding are stored in log files to enable later detailed inspection of the sounding process. Each time the DigiCORA III core processes are started, the system creates a backup of the parameter database and the necessary registry settings for later restoration, if required. 3.3 Message creation The real-time sounding data is stored in a global memory as Windows NT memorymapped files. The data storage process provides a generic messaging service. Any process may register as a client and be notified of sounding data changes, such as new levels or manually edited significant points. This enables configuration of a wide range of on-demand triggered events, realized through the triggering server and the spooling server. The main purpose of this software architecture is automatic generation and distribution of meteorological messages. Meteorological messages Several meteorological messages are available; the WMO standard messages, as well as BUFR and CREX. The NATO STANAG module extends the use of DigiCORAIII to customers with tactical weather observation needs. The available messages, parameters and message formats are specified in the DigiCORAIII database. The user can predefine which messages should be generated at what time during or after the sounding. The user is also able to configure where the messages should be sent and whether a header or footer section should be appended. Real-time message generation is invoked by utilizing the triggering server. Triggering The triggering server is designed to launch predefined actions according to user-specified conditions. In addition to the main purpose of this software module automatic message generation based on monitored sounding data the triggering server is also able to launch a wide range of other tasks, such as special data calculations, audible messages, and sounding data printouts. The triggering server monitors sounding data in real-time through notifications from the process which handles the sounding data storage. The triggers are implemented using a simple scripting language, which allows simple flow control, calls of external functions, and accessing current sounding data. As a specified notification about a change in monitored sounding data is received, e.g. a new data layer is available, a trigger script is executed. If the specified conditions in the script are fulfilled, the actions defined in the script are taken. Spooling When a message has been automatically or manually generated, it is put in a temporary storage. The spooler server sees to it that the message is sent to its destination. The spooler server is a process that transfers data at predefined intervals to predefined target devices. The targets for each message are defined in the database. The spooler server frequently checks the temporary storage for generated messages. When a message is found, the spooler server checks the database for target destinations and distributes the message. The messages can be sent to logical files, serial ports, another spooler server and external processes through standard output streams. The spooler server together with the triggering server and scripting language provides a powerful tool for configuring almost any user-defined action according to the available sounding data. 3.4 User interface The DigiCORA III user interface (UI) and user control process (UCP) combine sounding control, data management and meteorological message creation and provide the means to communicate and interact with the sounding processes. 155/

5 The main components of the UCP are: Faceless UI components providing basic UI functions and attributes without a visual outlook. Visible UI components providing a visual outlook for the user interface. System interface components linking with underlying sounding hardware and database services. The standard software provides the user with a uniform and familiar Windows-based graphical UI for all its functions. UCP Framework The UCP is the platform for specialized UI components. UCP handles dynamic invocation of user interface modules (UIM). All the UIMs are implemented as dynamically loaded libraries (DLLs) that can be installed in or removed from the system without any modifications to basic UI functions. Visualization The versatility of DigiCORA III software is increased with a variety of data visualization tools. The Metgraph module provides graphical representation /2001 Figure 2. Vaisala s DigiCORA III sounding system.

6 User privileges DigiCORA III UI is a MDI (Multiple Document Interface) application. In the basic mode, only one MDI child window is visible for the control of one real-time sounding or archived sounding. In the advanced user mode, several basic UI views may be active at the same time, facilitating the handling of archived sounding data simulof calculated sounding data and editing of significant points. The Metgraph view includes single or multiple graphs of temperature, humidity, wind speed and direction and wind components. The significant point editor can be invoked while viewing the graph and modifications can be verified immediately. Meteorological messages are generated according to the user-modified significant points. The Tephigram is a thermodynamic diagram used in operational meteorology. It is used for strict thermodynamic calculations. Its large angle between isotherms and dry adiabats renders it most effective for assessing degrees of stability. The Hodograph is a tool for looking at wind shear. Wind speed and direction as a function of height is plotted on a polar diagram, resulting in a graph that traces the vertical wind shear of the intervening layers. The Hodograph shows the effect of friction on wind speed and direction in the friction layer, and above it the relative stability of the atmosphere can be inferred from the plot. The way in which the hodograph rotates with height in the free air is important for determining thermal advection. These visualization tools can be operated in two modes. In the standard mode they are connected to only one sounding, and the edited data from this sounding can be viewed. In the advanced mode, it is possible to view multiple simultaneous soundings the present soundings and several archived ones. Wizards The UI module for the sounding operation guides the user through the various stages of preparing and launching the radiosonde. This module is wizard-like; the views always include instructive pictures or texts and can have voice output. Multiple sessions The DigiCORA III utilizes the advanced multi-tasking properties of Windows NT, which allow multiple sounding sessions to be run simultaneously. Each session has access to a common data source. Both live and simulated soundings are possible. Multiple sounding systems can be controlled from a single workstation, enabling the operation of multiple live soundings simultaneously. Voice output The system is able to guide the user with audible instructions during the operation. To enable the voice messages, a text-tospeech engine is integrated in the system. The voice messages can be used to notify the user about the completion of a certain task or of warnings or error situations. All voice messages can be modified and edited by the user. Localization The UI enhances system use through a configurable access level and translatable operator prompts. All the instruction strings and control texts in the basic mode of the DigiCORA III UI are easily translatable. A mechanism with a resource database is provided that enables the sounding control UI to load text strings depending on the currently selected language. The translation mechanism provides an easy and quick way to translate the basic sounding operation to any other language, including bitmaps and sound effects. All text strings, bitmaps and sound files are user-editable. 3.5 Configurability The open data management architecture and choice of operating system enable a very configurable yet secure system. Windows NT provides a means of specifying user groups and user privileges. taneously with a real-time sounding. User privileges are assigned rights to perform certain actions on the system. Examples of assignable privileges are: Privilege to edit a specific group of system parameters Privilege to change visual system options such as colors, appearance of the UI, etc. Privilege to use a specific UIM component of the system. Some privileges, such as to edit a group of system parameters, are implicitly defined, while others, such as to allow the user to select between wind calculation options, are explicitly defined. The privilege management system makes it easy to add or remove privileges when needed. User groups The users of the sounding software can be divided into groups according to the type of sounding tasks they perform. The default groups are sounding operators, sounding managers and administrators. The privileges of each group are stored in the DigiCORAIII database and can be adjusted according to local demands. The users are assigned to appropriate groups using the Windows NT user management tool. This utility can be used for a variety of purposes. For example, the parameter database access and advanced research options can be turned on and off by altering the user group rights in the database. Individual users The operating system s user management policy also enables individual configuration of the user interface. Users can have their own preferred settings of graphical tools like Metgraph. These adjustments are saved under each user s account in the Windows NT registry. 3.6 Sounding simulation Sounding simulation uses a selected archived sounding, and is in every respect like a live sounding. The simulation can be accelerated or decelerated as required. The only difference from a live sounding is that the sonde coefficients are not entered during the initial stages of the sounding. 4. User-friendly, highperformance solution The next generation radiosounding system, the Vaisala DigiCORA III, offers user-friendliness and high-performance with vastly improved system management. DigiCORA III sets new standards for upper-air sounding with its open software architecture, flexibility and networking capabilities. Distributed modular client/ server software architecture coupled with powerful networking capabilities on an industrial standard operating system open up new opportunities for remote data access, remote operating and remote maintenance of radiosounding systems. The DigiCORA III is an open system focused on users views and based on industry standards. The sounding workstation architecture provides many benefits for the user, in terms of both cost and maintainability. The sounding software with its self-explanatory user interface offers the simplest possible operation and lowers operator training requirements, while providing new functions and operating options that reach far into the future of upper air observations. The modular design gives an easy upgrade path from earlier generations of Vaisala Digi- CORA, since many of the familiar terms and functions of the previous models are employed. 155/