Glossary

• APRS - Automatic Position Reporting System. An amateur radio system originally developed to maintain an ongoing record of the location of a mobile radio-transmitter. It has been expanded to allow reporting of weather information within a position report. Originally restricted to reporting via amateur radio, it is now possible to send (and receive) these reports via the Internet. The Internet APRS system feeds data into the USA Hurricane warning center and other NOAA systems.

• ASOS - Automatic Surface Observing Station. Used for automatic METAR report generation. Has a ceilometer to measure cloud height and type automatically.

• CSV - Comma Separated Values/Variables. A computer file format in which individual data values are separated from each other by commas. Used in Excel and database software.

• DDE - Dynamic Data Exchange. A data transfer mechanism available within MicroSoft Windows that allows computer programs to directly exchange data. For example, WD can make its data available to EXCEL spreadsheets using DDE.

• FTP - File Transfer Protocol. FTP allows local or remote client and server machines to share files and data using the TCP (see also) transport mechanism. FTP is an interactive protocol with provisions to Copy (in either direction), Rename, or Delete files on a server machine.

• HTM - A file type designator. Most commonly used in Microsoft Windows computers to indicate that the file contains HTML content.

• HTML - HyperText Markup Language. The markup language with which World Wide Web (WWW) documents are written. It allows you to create hypertext links, fill-in forms, etc.

• HTTP - HyperText Transfer Protocol. The set of messages used between Web browsers and servers to provide a means to deliver requested documents, e.g. HTML files, to a user.

• IP - Internet Protocol. Data to be transmitted across a network, e.g. the Internet, is enclosed in a "datagram" with originating and destination addresses attached. Individual datagrams are sent via whatever route makes sense at that instant. Successive datagrams between the same points may take different routes. Datagrams are sent on a "best effort" basis and are not guaranteed to reach the recipient. The structure of datagrams is defined by the Internet Protocol specifications.

• ISP - Internet Service Provider. The company you have chosen to give you Internet access, e.g. AOL, Plus Net, Freeserve, etc.

• LAN - Local Area Network. A network covering a small area, e.g. a building or a group of buildings within a a few hundreds of metres of each other.

• METAR - An acronym derived from the French, and basically meaning "aerodrome weather". This weather observation coding format is the primary format for weather data distribution in North America, though it is used at many airports in other regions. The format is relatively readable and is designed mostly for the aviation sector. METAR observations are usually taken every hour, although larger airports may produce a report every 30 minutes. Special reports can also be sent when conditions have changed significantly since the last report was sent. (Part of this definition is from "Weather Forecasting Handbook", 5th ed., Tim Vasquez).

• MIME - Multipurpose Internet Mail Extension. A definitive list of file types used by Email clients and Web Browsers (among others) to determine how to process the content of a file.

• NOAA - National Oceanic & Atmospheric Administration. A part of the United States Department of Commerce. The parent agency of the US National Weather Service.

• SMTP - Simple Mail Transport Protocol. The set of processes used for email transmission by the bulk today's internet email systems. In practice, this protocol gets the email from the originator to the email server supporting the recipient(s). Actual email receipt is usually handled using either POP (see also) or IMAP (see also).

• SYNOP - Synoptic Observation. This observation coding format is used worldwide, and comprises the primary method for weather distibution outside of North America. The format, designed mainly for meteorologists, consists of blocks of numerical data. The observations are usually taken every 6 or 12 hours (sometimes every three). (From "Weather Forecasting Handbook", 5th ed., Tim Vasquez)

• TCP - Transmission Control Protocol. Data to be transmitted across a network, e.g. the Interet, is broken up into "packets" of a specific number of characters for transmission over a network within an IP (see also) envelope. Since the nature of computer networks is such that the delivery of packets can not be guaranteed, each packet also contains additional information that the receiving computer can use to assure that all packets have been received and placed into their correct order. This information is defined in the TCP standards specifications.

• URL - Uniform Resource Locator. The unique address of a document on the World Wide Web, e.g http://www.weather-watch.com/smf/index.php. A URL consists of the document name (index.php) preceded by the hierarchy of directory names in which the document is stored (/smf), the Internet Domain name of the server that hosts the file (www.weather-watch.com), and the software and manner by which the browser and the document's host server communicate to exchange the document (http://).

• WAP - Wireless Application Protocol. The description of a data format suitable for viewing on mobile phones that have this facility.

• WD - Weather Display. Software which collects data from a variety of automatic weather station types and displays it on a computer and formats the data for display on web pages.

• Wind run - A measurement of how much wind has passed a given point in a period of time. A wind blowing at three miles per hour for an entire hour would give a wind run of three miles.

• Wunderground - A contraction of Weather Underground. A program of the University of Michigan that posts weather observations from private weather stations around the country on a web site.