A new series in this generation
began with the launch of TIROS-N on October 13, 1978. This satellite was the first
in that series to carry the AVHRR (described on page 14-2), along with
the first sounder, TIROS Operational Vertical Sounder (TOVS), designed to profile
temperature and water vapor. The TOVS is actually a three instrument complex:
the High Resolution IR Sounder (HIRS-2), with 20 channels; the Stratospheric Sounding
Unit (SSU), with three channels near 15 µm, and the Microwave Sounding Unit (MSU),
a passive scanning microwave spectrometer with four channels in the 5.5 µm interval.
These instruments are the
mainstays of the subsequent NOAA-6 (launched on June 27, 1979) through NOAA-15
(May 1998) metsats. The SBUV is also part of NOAA-9 and NOAA-11. Even-numbered
NOAA metsats have North to South equatorial crossing times near 7:30 A.M. and
have orbital repeat periods (re-occupy approximately the same paths) of four
to five days. The odd-numbered ones cross the equator from North to South at
night (2:30 A.M.) and have eight-nine day repeat periods. NOAA strives to keep
as many as four satellites in this series operational at any one time.
The thermal bands on AVHRR
can generate temperature "maps" of water bodies, both oceans and lakes. Here
is a thermal image of the temperature in early Fall in the five U.S. Great Lakes:
Here is a NOAA-9 AVHRR image
in the visible region of Hurricane Gloria, as it neared the East Coast on September
27, 1997:
Next, a NOAA-6 IR image, in
which lighter tones are color-enhanced to bring out details, of Super Typhoon
Angela in the western Pacific, shows its status on November 11, 1995:
Like most multi-channel systems,
we can combine different AVHRR-band images into color composites, as demonstrated
by this NOAA-14 rendition of Hurricane Fran on September 4, 1996:
14-15:
This is a classic portrayal of a hurricane's appearance.
Deduce from the directions of motion implied by the swirls in the hurricane's
spiral pattern which way the circulation (clockwise or counterclockwise) of
the winds is taking place. ANSWER
The NOAA daily images are
compiled and displayed in different formats. Here is a NOAA-14 image taken on
June 26, 2000 that covers European Russian eastward into Siberia.
The latest in the NOAA
group, NOAA-15, has these instruments: AVHRR/3; AMSU A & B (sounders); HIRS
(an infrared sounder); SEN (Space Environmental Monitor); SAR (Search and Rescue);
and DCS (Data Collection System. Its AVHRR now has a sixth band, at 1.6 µm.
The AMSU-A is capable of producing temperature profiles, as exemplified by this
cross-section through Hurricane Bonnie.
The former Soviet Union/CIS
has launched more than 25 polar-orbiting metsats in its three Meteor Series,
starting in March of 1969, and continuing through 1994. Other metsats were part
of their Kosmos series China, too, is now in the
metsat field. Here is an image of the "wayward province", Taiwan, imaged by
its polar-orbiting Fengyun (FY-1C) satellite on May 10, 1999.
