For the humans, it has always been important to predict the meteorological condition especially for the agriculture. With the development of the worldwide commerce, an increase of maritime exchange has been observed. To provide a security for the ships, in 1807, the American President Thomas Jefferson founded the U.S. Coast and Geodetic Survey (as the Survey of the Coast). The goal of this agency is to provide nautical charts to the maritime community for safe passage into American ports and along our extensive coastline. After that, in 1870, The Weather Bureau was founded and, one year later, the U.S. Commission of Fish and Fisheries was founded. Individually, these organizations were America's first physical science agency, America's first agency dedicated specifically to the atmospheric sciences, and America's first conservation agency.
The 3rd of October 1970, Richard Nixon proposed creating a new agency to serve a national need "… for better protection of life and property from natural hazards … for a better understanding of the total environment … [and] for exploration and development leading to the intelligent use of our marine resources ...". This new agency is National Oceanic and Atmospheric Administration, commonly named NOAA. This new agency regroups the three previous agencies presented previously: U.S. Coast and Geodetic Survey, Weather Bureau U.S. Commission of Fish and Fisheries. NOAA depends on the Department of Commerce of United States of America.
NOAA has three principal missions articulated around the domain of Science, Service and Stewardship. These missions are:
• To understand and predict changes in climate, weather, oceans and coasts;
• To share that knowledge and information with others;
• To conserve and manage coastal and marine ecosystems and resources.
To achieve their missions, NOAA launched satellites to observe and transmit information about climate and weather. They use two type of satellite: Geostationary Operational Environmental Satellites and Polar-orbiting Operational Environmental Satellites.
The GOES satellites stay above a fixed spot on the surface, they provide a constant vigil for the atmospheric "triggers" for severe weather conditions such as tornadoes, flash floods, hail storms, and hurricanes. When these conditions develop the GOES satellites are able to monitor storm development and track their movements. GOES satellite imagery is also used to estimate rainfall during the thunderstorms and hurricanes for flash flood warnings, as well as estimates snowfall accumulations and overall extent of snow cover.
The POES satellite system offers the advantage of daily global coverage, by making nearly polar orbits 14 times per day approximately 520 miles above the surface of the Earth. The Earth's rotation allows the satellite to see a different view with each orbit, and each satellite provides two complete views of weather around the world each day. The satellites provide visible, infrared, and microwave data which is used for a variety of applications such as cloud and precipitation monitoring, determination of surface properties, and humidity profiles.
The world's first meteorological POES satellite was launched in 1960 from Cape Canaveral in Florida. It was the Television Infrared Observation Satellite, most commonly named TIROS. This satellite demonstrated the benefit of mapping the Earth's cloud cover from satellite altitudes. TIROS showed clouds banded and clustered in unexpected ways. Sightings from the surface had not prepared meteorologists for the interpretation of the cloud patterns that the view from an orbiting satellite would show.
After the creation of NOAA in 1970, the first of the improved satellites was launched. This satellite was the Improved TIROS Operational Satellite, also named ITOS 1. Five ITOS satellites designated NOAA-1 through 5 were launched between December 1970 and July 1976.
Currently, the available POES satellites which delivered APT signal are the following: NOAA 15 (137.62 MHZ) launched in 1998, NOAA 18 (137.9125 MHz) launched in 2005 and NOAA 19 (137.1 MHz) launched in 2009. These satellites are distant from Earth to 800 km. Their inclination angle is near to 98°, depending of each one. They have an orbital period around 102 minutes. Thus, the satellite system can offer 14 polar orbits per day. Each satellite take pictures of a dedicated place twice a day.
During our project, we will use the data emitting from the POES satellites in order to recover the weather observation images. In the next part, we will present in more details the POES satellite. Thanks to the tracking software WXTracking which allows us to follow each NOAA satellite, we are able to know exactly the position, the visibility duration, the angle of elevation needed and the time when each satellite will pass above Toulouse.