U. S. Polar Orbiting Weather Satellites

It is appropriate that we have a web page devoted to weather satellites here at PARI.  They are part of our heritage and represent the intense research & development effort that occurred, not only at the Rosman site, but also throughout the US during the Cold War/Space Race - A cycle of education that still continues to this day at the site!

     RAW IMAGES

The raw images above show the real-time, low resolution data that consists of two data channels which vary according to day/night conditions.  IR imagery is useful for determining cloud features both at day and night whereas visible and IR channels are combined for day time use.

    ENHANCED IMAGE

More information with a list of upcoming satellite passes and a few more composite enhancements can be found at http://web.comporium.net/~lghalsey/

The enhanced image above is downloaded to a receiver located near the PARI East 26-m radio telescope.  This image shows the enhanced information - Colder objects are brighter and warmer objects are darker. Lower layers of clouds, generally warmer and lower in altitude, are colored gray. Colder and generally higher clouds tops are highlighted in colors.  The image updates about every 3 hours.

We are using the direct readout service from a class of weather satellites known as polar orbiters.  This page shows the most recent Automatic Picture Transmission  (APT) images of the United States as taken from a NOAA satellite as it passes within range of PARI.  As the name implies, their orbit is a relatively low (450 n. mile altitude) path oriented on the poles.  They are in a sun synchronous orbit which means they arrive over a given point of the earth at about the same Local Solar Time each day.

An image of the Automatic Picture Transmission (APT) receiving antenna at PARI is shown below.  The full name for this helical antenna is a Quadrifilar Helical Antenna. The PARI 26-m East Radio telescope is seen in the background.

A BIT OF HISTORY...

Rosman Station (now PARI) was authorized in December of 1961 as the first in the new 2^nd generation of tracking stations and was on-line by 1962. The first 85 foot dish was completed and operational by 1963.  The 2^nd 85 foot dish was completed in 1964. These dishes, as well as other antennae on-site, were used to track, monitor, interrogate, and command not only the early weather satellites (such as Nimbus, ATS, TIROS) but also numerous other NASA experimental satellites as well.

For users who want to establish their own analog direct readout receiving station, low resolution imagery data in the APT service can be received with inexpensive equipment, while the highest resolution data transmitted in the HRPT service utilizes a more complex digital receiver.

More information about the APT service can be found at this website - http://www2.ncdc.noaa.gov/docs/klm/html/c4/sec4-2.htm

 More detailed information about US and European P.O. satellites can be found at this website –

http://projects.osd.noaa.gov/IJPS/product.htm

The receiver was installed and is maintained by John Halsey, PARI Director of Remote Sensing and Atmospheric Sciences Laboratory.  For more information, contact John at:

jhalsey@pari.edu