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.)
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 also in a near polar orbit and 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.
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| CERES Overpass Calculator | Clickable Geostationary Map |
In May 2004, new observing times were announced to help validate the time interpolation activity for CERES. Click on the map above right, then click on your part of the world 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
much sooner than that.)
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.
