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NOAA
The NOAA
(National Oceanic and Atmospheric Administration) satellites
have a very long and distinguished history. The U.S. meteorological
programme started in 1960 with the launch of TIROS-1 (Television
and Infrared Observation Satellite). The TIROS programme
was the result of an international collaboration between the U.S.,
the United Kingdom and France.
In 1970, infrared sensors were added to the satellites
payload, allowing image acquisition during both night and day. From
then on the satellites were renamed NOAA.
As of 1978, NOAA satellites were equipped with
the Advanced Very High Resolution Radiometer (AVHRR), an instrument
sensing in the visible, near infrared, mid-infrared and thermal
infrared portions of the electromagnetic spectrum.
In 50 years, five generations of satellites followed
one another: TIROS (10 satellites), ESSA (9 satellites), ITOS (8
satellites), TIROS-N (3 satellites) and ATN (Advanced TIROS-N, 13
satellites to date).
The POES
(Polar Operational Environmental Satellite) programme includes
the last 2 series. Five NOAA satellites are currently operational.
The last one, NOAA-19, was launched in February 2009.
NOAA maintains at least two operational satellites
in complemenatry orbits, with the even-numbered satellites crossing
the equator in the early morning and early evening and the odd-numbered
satellites crossing the equator in the afternoon and late evening.
Together they provide twice-daily global coverage, and ensure that
data for any region of the Earth are no more than six hours old.
NOAA satellites allow to monitor, on a global
scale, snow and sea ice extents, water surface temperatures, or
vertical profiles of atmospheric temperature and humidity.
Characteristics of NOAA-15
to NOAA-19
altitude: 807 - 870 km
inclination: 98.5° - 99°
orbit: Quasi polar, sunsynchronous
orbit period: 101-102 minutes
revisit time: 1 day
AVHRR/3
(Advanced Very High Resolution Radiometer)
The Scanning Radiometer AVHRR is characterized by a very wide field
of view. Its swath is 2940 km and its spatial resolution is 1 km
in the infrared and 0.5 km in the visible. Twice a day, the instrument
provides images of the cloud cover over the entire world, and it
also offers frequent images of the land and sea surfaces. The instrument
is especially well-suited for studying vegetation on a world scale,
e.g. for the study of seasonal changes. It also allows to monitor
sea surface temperatures and the ice covering extent.
| Band |
Band width |
Applications |
| 1 (visible) |
0,58 - 0,68 µm |
Clouds and land surfaces cartography
(day) |
| 2 (Near IR) |
0,725 - 1,00 µm |
Clouds and land surfaces cartography
(day) |
| 3A (Near IR) |
1,580 - 1,64 µm |
Snow and ice detection |
| 3B (IR) |
3,550 - 3,93 µm |
Clouds and sea surface temperature
mapping (night) |
| 4 (IR) |
10,30 - 11,30 µm |
Clouds and sea surface temperature
mapping (night) |
| 5 (IR) |
11,50 - 12,50 µm |
Sea surface temperature |
AMSU-A1, -A2 en -B (Advanced Microwave
Sounding Units)
AMSU-A possesses 15 channels in the microwave range and allows one
to calculate vertical temperature profiles from the Earth's surface
up to a pressure of around 3hPa (45 km), even in the presence of
clouds. AMSU works in a complementary manner to HIRS, which has
a better resolution than AMSU but is more affected by clouds.
AMSU-B has 5 channels and also measures moisture profiles.
HIRS/4
(High Resolution Infrared Radiation Sounder)
HIRS has 20 channels (1 visible: 0.69 µm, 7 short wavelength
channels: 3.7 – 4.6 µm and 12 long wavelength channels:
6.7 - 15 µm). This instrument delivers high-resolution temperature
profiles under cloudless conditions. These measurements are of great
importance for meteorology and climatology.
SBUV/2 (The Solar Backscatter
Ultraviolet Spectral Radiometer)
From the measurements made with this instrument, one can derive
atmospheric characteristics related to stratospheric ozone (the
global and vertical distribution, the structure and dynamics thereof,
etc.).
SEM-2 (Space Environment
Monitor)
SEM-2 measures the flow of charged particles up at the satellite's
altitude, and thus contributes to our understanding of the "sun-earth"
system.
SAR (Search and Rescue
Repeater and Processor Support)
The Search and Rescue system, sponsored by Canada, France, Russia
and the USA, uses satellites and other means to receive emergency
signals sent from ships, airplanes, land expeditions, and even from
individuals having the right equipment.
Mission website
Data distributors:
U.S.
Geological Survey
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