WAFS

The World Area Forecast System (WAFS) was established by the ICAO Communications/Meteorology (COM/MET) Divisional Meeting held conjointly with the seventh session of the WMO Commission for Aeronautical Meteorology (CAeM) in Montreal in 1982. The objectives of the system are "to supply meteorological authorities and users with forecasts of en-route meteorological conditions in pictorial, alphanumeric and digital form. These objectives are to be achieved in a cost-effective manner through a comprehensive, integrated worldwide, and, as far as is practicable, uniform system".

The meteorological information as regards en-route conditions for pre-flight and in-flight planning and for the selection of organized tracks comprises forecasts of global:

To facilitate computerized processing, the system provides the products under a) to f) in standardized digital format using the gridded binary (GRIB) code (WMO FM 92-IX Ext. GRIB refers) and product g) in the binary universal format for representation of meteorological data (BUFR) code (WMO FM 94-XII Ext. BUFR refers).

The foregoing products are distributed globally by the two world area forecast centres (WAFC), London and Washington by satellite broadcast as part of the ICAO aeronautical fixed service (AFS). WAFS products consist of aeronautical meteorological information of an operational nature. There is therefore an obligation for ICAO to ensure that all ICAO Contracting States have access to all the WAFS data they may need through at least one component of the AFS.

In order to meet growing requirements for operational meteorological (OPMET) information in alphanumeric form, such as aerodrome routine meteorological reports (METAR), aerodrome forecasts (TAF), SIGMET, and special air-reports (special AIREP), character-oriented OPMET information is also disseminated via the satellite broadcasts in real time.

The worldwide satellite communications are provided using four INTELSAT satellites.

The United States provide three INTELSAT services for the distribution of WAFC Washington products over the Americas, Pacific and Eastern Asia, using INTELSAT satellites based over the Atlantic, the Pacific and Indian Oceans. The services provided by the United States are known as the International Satellite Communications System (ISCS).

To meet the requirements for WAFS dissemination in Europe, the EANPG developed a system for the distribution of WAFS data via satellite, as one component of the AFS. Originally the system was intended to serve the ICAO European (EUR) and Middle East (MID) Regions, but it was subsequently extended to serve the Africa-Indian Ocean (AFI) Region and the western part of the ASIA Region. The system is now capable of serving all States in the AFI and MID Regions and the ASIA and EUR States up to about 140° East and is known as the Satellite Distribution System for Information Relating to Air Navigation (SADIS).


SADIS

SADIS is an operational system dedicated primarily to aeronautical meteorological information in line with ICAO worldwide provisions. WAFS forecasts and OPMET information are disseminated without conflict or delay caused by the dissemination of non-operational data. As an ICAO system forming part of the AFS, it has been designed to meet the worldwide Standards and Recommended Practices (SARPs) promulgated in ICAO Annex 3 — Meteorological Service for International Air Navigation and Annex 10 — Aeronautical Telecommunications. This ensures full availability of the service and the largely error free transmission of all information required for pre-flight planning. WAFS GRIB and BUFR forecasts will be backed up, with WAFC London and WAFC Washington products being interchangeable.

SADIS provides a point to multi-point service on a 24-hour basis via satellite. The SADIS uplink is situated at the Cable & Wireless hub at Whitehill Earth Station, north of Oxford in the United Kingdom. The WAFS data is provided from WAFC London in the United Kingdom Met Office (referred to as “Met Office”), Exeter, via terrestrial 64 kilobits per second (kbps) lines and are uplinked from the hub at Whitehill to the INTELSAT satellite 904 located over the Indian Ocean at 60°E. The OPMET data is provided by the National Air Traffic Services (NATS) SADIS Gateway facility (supplied by NetSys) at Swanwick near Southampton. Data from the Gateway is transmitted via a switched virtual circuit (SVC) to the Met Office for onward promulgation via the aforementioned terrestrial leased lines to Whitehill. The data are downlinked via a global beam to users anywhere in the AFI and MID Regions and in the ASIA and EUR Regions as far eastwards as 140°E.

SADIS User Guide

SADIS Indian Ocean

INTEL SAT 904



ISCS


ISCS support for WAFS is in response to ICAO and WMO requirements. ISCS and SADIS make up the worldwide WAFS program providing vital meteorological support for flight planning and air traffic management throughout the world. The purpose of ISCS/SADIS is to provide the worldwide aviation community with operational meteorological forecasts and information about meteorological phenomena required for flight planning and safe, economic and efficient air navigation.
ISCS provides a point to multi-point service on a 24-hour basis via satellite. ISCS uplinks are situated at the three Gateways in Andover, Maine; Yacolt, Washington; and Fuchsstadt, Germany. WAFS data is provided from Washington WAFC Center in the United States and are uplinked from the hubs at Andover, ME to the INTELSAT satellite 903 located over the Atlantic Ocean and Yacolt, Washington for utilization of the INTELSAT 701, and Fuchsstadt, Germany for utilization of the INTELSAT 906 over the Pacific Ocean.
The data is delivered to the end user using Transmission Control Protocol/Internet Protocol (TCP/IP). A computer processing system (workstation or mini-computer) must be connected to the communications port of the network interface device. This computer system is selectable by the user, but the interface of the selected computer must be prepared to utilize Hughes Network Systems = Program Director (PD) Receiver software to enable reception of IP multicast data stream. The system can be a stand alone workstation as the third component of the ISCS. This component receives the data stream and stores the data for retrieval and use.
ISCS User Guide

ISCS Atlantic Ocean Region (AOR)

COUNTRIES / LOCATIONS SERVED BY THE ISCS ATLANTIC OCEAN REGION (AOR) BROADCAST

INTEL SAT 903

Carribean

Anguilla Cayman Islands Haiti St. Martin
Antigua Cuba Jamaica Sint Maarten
Aruba Curacao Martinique St. Vincent
Azores Dominican Republic Montserrat Tortola
Bahamas Dominica Puerto Rico Trinidad & Tabago
Barbados Grenada St. Kitts
Bermuda Guadeloupe St. Lucia

Central America

Belize EL Salvador Honduras Panama
Colombia Ecuador Mexico
Costa Rica Guatemala Nicaragua

South America

Argentina Chile Paraguay Uruguay
Bolivia French Guiana Peru Venezuela
Brazil Guyana Suriname

North America

Canada United States

West Africa

Niger

United Kingdom

England

ISCS Pacific Ocean Region (POR)

INTELSAT 701


American Samoa Fiji New Caledonia Vanuatu
Australia French Polynesia Niue Island (Korea) Hawaii
Brunei Indonesia Papua New Guinea Caroline Island
Japan Peoples Republic of China China (Mainland) Johnson Island
Philippines Cook Island Kiribati Republic of Korea
North Korea Mariana Islands Samoa East Timor
Marshall Islands Solomon Islands Easter Island Nauru
Tonga

ISCS Indian Ocean Region (IOR)

INTELSAT 906

Malaysia Thailand Vietnam