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S'COOL: When to Observe Clouds

We request that you make your cloud observations within +/- 15 minutes of the passage of a CERES instrument over your part of the world. This is because clouds change on the timescale of minutes. To get overpass times for your location you will need to know what time zone you are in (don't forget Daylight Saving Time ). If you don't know your timezone you may determine it by calculating your Universal Time offset. (For more information on time zones, DST, etc, follow this link.)

Your latitude/longitude location is also, of course, key to this calculation. This was provided with your registration but you can verify it using Google Earth below.

Check your school location in Google Earth

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CERES instruments are in orbit on three different satellites: TRMM, Terra, and Aqua.

The TRMM satellite, launched in November 1997, is in a low inclination orbit which can see mostly the Tropics (actually about 40 S to 40 N latitude). There are a number of surface/satellite matches with CERES data collected from TRMM in our database. However, the CERES instrument on this satellite is no longer collecting data.

The Terra satellite, launched on December 18,1999, is orbiting in a near polar orbit and sees every part of the world during daylight at least once every day. It passes over generally around 10:30 a.m. local time.

The Aqua satellite launched into orbit on May 4, 2002. Like the Terra satellite, Aqua is in a near polar orbit but passes over at roughly 13:30 local time, providing another scheduling option for our participants around the globe.

To obtain observing times for these satellites, click on the CERES Overpass Calculator below at left.

CERES Overpass Calculator	Geostationary Observation Times

In May 2004, new observing times were announced to help validate the time interpolation activity for CERES. Click on the map above right, to determine the geostationary times for your location.

See a sample overpass report for an explanation of the overpass schedule you will receive.
(Satellite Overpass Schedules will be sent to your e-mail address within 24 hours of your request - most often they will arrive within minutes.)

You may want to check out a web-based orbit visualizer (JTrack or Heavens Above) to get a better understanding of these orbits. The latter site also has some information about when and how you can see the satellite.