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Weather affects everyone - food supplies, travel, recreation
- and along with other applications satellites, the weather satellites
have brought special advantages to life on Earth. They enable people
to plan ahead, assist meteorologists with forecasting, and help
scientists to understand better the air around us.
Advance knowledge of weather systems that can be disastrous
is the most striking advantage; part of that knowledge comes from the
ability to see the sparsely populated regions of the world where
weather is born, thus aiding long-term prediction. For local
meteorologists, daily photographs show how their local weather
patterns fit into the overall picture.
On April 1, 1960, TIROS 1, the first true weather satellite,
was launched. With each succeeding generation of satellites, remote
sensing instruments became increasingly sophisticated and today's high
quality pictures are a far cry from the first tentative trials.
The Television and Infrared Observation Satellite (TIROS)
was a simple hatbox-shaped craft carrying special television cameras
that viewed Earth's cloud cover from a 450 mile orbit. The pictures
radioed back to Earth provided meteorologists with a new tool - a
nephanalysis, or cloud chart.
By 1965, nine more TIROS satellites were launched. They had
progressively longer operational times, carried infrared radiometers
to study Earth's heat distribution, and several were placed in polar
orbits to increase picture coverage over the first TIROS in its
near-equatorial orbit.
TIROS 8 had the first Automatic Picture Transmission (APT)
equipment that allowed pictures to be sent back right after they were
taken instead of having to be stored for later transmission.
Eventually, APT pictures could be received on fairly simple ground
stations anywhere in the world, even in high school classrooms.
TIROS 9 and 10 were test satellites of improved
configurations for the Tiros Operational Satellite (TOS) system.
(When it became part of another acronym, TIROS was written Tiros.)
Operational use started in 1966. In orbit, the TOS
satellites were called ESSA for the Environmental Sciences Services
Administration, the government agency that financed and operated them.
TOS satellites were placed in Sun-synchronous orbits, so they passed
over the same position on Earth's surface at exactly the same time
each day; this allowed meteorologists to view local cloud changes on a
24-hour basis.
Several ITOS (for Improved TOS satellites) have been
launched since 1970 and are the workhorses of the meteorologists. In
orbit they are called NOAA for the National Oceanographic and
Atmospheric Administration which is responsible for their operation.