SATELLITES

How were the first high altitude photographs of clouds taken?

During World War II, cameras were mounted aboard some of Germany's V2 rockets to take pictures of cloud patterns. The success of these efforts inspired meteorologists to plan for weather satellites.

What was the first satellite used for monitoring the weather?

The first man-made satellite used to monitor weather conditions was the Television and Infrared Observation Satellite (TIROS I), which was launched by NASA on April 1, 1960. While the photographs taken were not of the high-resolution standards we

A circa 1961 illustration of TIROS I shows its various components. (NOAA).

A circa 1961 illustration of TIROS I shows its various components. (NOAA).

see today, they were the first to reveal just how clouds and storms can be remarkably well organized, a fact that surprised meteorologists at the time. TIROS I's other groundbreaking accomplishment was to spot a previously undetected tropical storm near Australia nine days after its launch. Australians along that country's east coast were thus the first people, thanks to modern technology, to get a heads up that a strong storm was approaching.

What remarkable observation did science fiction author Arthur C. Clarke make?

Arthur C. Clarke (1917-2008) is well known to science fiction fans. His 1948 short story "The Sentinel" was the basis for the 1968 film 2001: A Space Odyssey. Among his many accomplishments, he was also very interested in satellites. During World War II, Clarke was a radar technician for the Royal Air Force, and in 1945 he proposed designs for a communications system using satellites. He reasoned that this was possible if satellites could be placed in orbit above the equator while traveling 22,248 miles (35,797 kilometers) per hour. This would put them in geostationary orbit, meaning that each satellite would remain directly above a predetermined point on the Earth's surface. This idea proved correct, and is used now for both communications and weather satellites. The Clarke Belt, a band of space over the equator at an altitude of 22,300 miles (35,800 kilometers) where geostationary satellites may orbit, is named in his honor.

A composite of photos from the TIROS IX, this image from February 13,1965, is the first complete view of our planet

A composite of photos from the TIROS IX, this image from February 13,1965, is the first complete view of our planet's weather. (NOAA)

What are the different types of satellites used today?

The two types of satellites used for weather observations are geostationary and polar orbiting. Geostationary satellites remain above a fixed point on the Earth's equator by traveling at a speed that matches that of the planet's spin; polar orbiting satellites circle the Earth from pole to pole. These satellites orbit at a speed so that, two times a day, they are over the exact same spot on the planet in what is called a "Sun-synchronous" orbit.

What is POES?

POES is an acronym for Polar Operational Environmental Satellite. These are the successors to the TIROS satellites, and they are thus called the Advanced Television Infrared Observation Satellites (ATN or TIROS-N). Like the GOES, there are two POES operated by the U.S. Department of Defense's Air Force Space and Missile System Center in what is called the Defense Meteorological Satellite Program. The POES orbit the Earth at elevations ranging from 515 to 540 miles (830 to 870 kilometers) in altitude, with one crossing the equator at 7:30 a.m. and 1:40 p.m.. Data is then transmitted to stations located at Wallops Island, Virginia, and in Fairbanks, Alaska.

What is a GOES?

GOES stands for Geostationary Operational Environmental Satellite. The first GOES was launched in 1975. Currently, the National Oceanic and Atmospheric Administration (NOAA) operates two such satellites that were launched by the National Aeronautics and Space Administration (NASA): GOES-10 and GOES-12. There is also a backup satellite, GOES-11, which can be activated in the event that one of the other satellites malfunctions. GOES-10 is also known as GOES-West because it monitors the sky over the Western Hemisphere; and GOES-12 (GOES-

What is the Solar and Heliospheric Observatory (SOHO)?

SOHO is a satellite paid for and launched through a cooperative effort between NASA and the European Space Agency. Launched on December 2, 1995, the satellite makes observations about the Sun's corona and solar winds, and it is also intended to try and study the Sun's inner core. SOHO has provided scientists with information about sunspot structure and solar wind speeds; the satellite has taken photographs of the Sun's turbulent convection zone, and it has discovered solar tornadoes and coronal waves.

East) monitors the Eastern Hemisphere. Each satellite is capable of viewing about one-third of the sky at any one time.

What other countries also have weather satellites in orbit?

Currently, the following countries have weather satellite programs: Japan, Russia, China, India, South Korea, and Europe (European Space Agency). Japan launched its Geosynchronous Meteorological Satellite Himawari in 1995, but in 2003 it malfunctioned, and so NOAA permitted the Japan Meteorological Agency use of the older GOES-9 satellite. The European Organization for the Exploitation of Meteorological Satellites (EUMETSAT) operates what is now the second generation of METEOSAT satellites. Europe launched its first weather satellite in 1995, and this second generation came online in 2004 with METEOSAT-8. This satellite scans the entire globe every 15 minutes. China launched the Feng-Yun in 1990, and there have been several successors since then. That same year, Russia launched GOMS (Geosynchronous Operational Meteorological Satellite). The Indian Satellite (INSAT) made orbit in 1990, and was used for both weather observations and communications. It was followed by INSAT-2 through INSAT-4 series, before the KALPANA-1 was operational in 2002. The KALPANA-1 satellite is India's first exclusively meteorological satellite. South Korea's first weather satellite is the Communication, Ocean and Meteorological Satellite (COMS), which was launched in 2005.

How did the KALPANA-1 get its name?

India's KALPANA-1 satellite was originally called the METSAT (meteorological satellite). However, it was renamed in honor of Kalpana Chawla, the Indian astronaut who died in the space shuttle Columbia disaster on February 1, 2003.

What measurements do weather satellites provide us?

Early weather satellites transmitted images of clouds and could also take infrared (IR) readings, which allowed for weather monitoring both day and night. With IR sensors, satellites can detect temperature readings, which can also indicate cloud elevation. Modern satellites are capable of many other observations, as well. Detailed images of not only clouds, but also land and sea surfaces and temperatures, provide scientists with information about fog, snow, rain, ocean currents, haze, air pollution, ozone levels, soil moisture levels, airborne dust, and even volcano and forest fire activity. Satellites are also used to take surveys of agricultural activities and vegetation growth.

What is the Landsat Program?

In 1972, NASA launched the first Landsat (land satellite) in cooperation with the U.S. Geological Survey. While taking photos and measurements related to the planet's surface, these satellites also provide a considerable amount of weather-related information. For example, Landsat satellite data has recorded the impacts of weather disasters, monitors flooding, and takes other measurements of interest to hydrologists. Recent surveys of land use have also resulted in studies about the effects of human activities on weather. For example, in 2006, an atmospheric modeling study was conducted on the state of Florida. Scientists compared estimates of vegetation coverage in the year 1900 with present conditions and demonstrated how urban and rural activities were affecting rainfall. It was estimated that Florida now experiences 12 percent less rain than it would have a century ago.

The SOHO spacecraft captured this image of the Sun shooting coronal mass ejections (CMEs) of plasma out into space. CMEs occur every week, and sometimes more than once a day. (NASA/JPL)

The SOHO spacecraft captured this image of the Sun shooting coronal mass ejections (CMEs) of plasma out into space. CMEs occur every week, and sometimes more than once a day. (NASA/JPL)

 
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