Patagonia School -Spanish Courses-

We have our own for participate in the Nasa project

Every day Patagonia School students submit their ground observation.

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.

What to Observe and Record

Time/Satellite

Next we ask you to identify when the observation took place and the name of the overpassing satellite. We need the exact time of the observation, even if it does not exactly coincide with the satellite overpass. This must be reported in both local and Universal Time (UT) to provide a uniform time reference for the observations. To convert your local time to UT, see this worksheet.

Cloud Observations

The cloud properties we are seeking are cloud type, cloud height, cloud cover , and visual opacity or cloud thickness. See an example from the initial pilot test.

You should only report cloud properties for levels you actually observe. If there are no clouds in a layer, leave that layer blank. If there is a completely overcast low layer that you cannot see through, leave the other two layers blank.

Note: When recording cloud type we would like you to determine which is the most prevalent cloud type for each level observed. Use the comments section to record that other cloud types were also present.

You say you're not completely sure whether that's stratus or stratocumulus? Then check this for a discussion of how accurate you need to be. You may also want to use a Dichotomous Key for Cloud Identification (developed by Dr. Tina Cartwright).

We have added some questions on contrails - condensation trails are clouds formed by the passage of aircraft. This information will be used by CERES researcher Dr. Patrick Minnis, in attempting to assess whether aircraft traffic may have some influence on Earth's climate.

Ground Observations

We also ask for some information about the surface conditions where you made the observation: surface cover, temperature, pressure, and relative humidity.

Only the surface cover information is required. You can submit any or all of the other measurements, depending on your situation.

What is CERES?

CERES - Clouds and the Earth's Radiant Energy Sytem - is a high priority scientific satellite instrument which is now orbiting the Earth as part of NASA's Earth Science Enterprise (formerly known as Mission to Planet Earth). Scientists are using it to study the ways in which clouds may affect the Earth's climate. You can find detailed information on CERES at: http://asd-www.larc.nasa.gov/ceres/ASDceres.html. A NASA lithograph (photo with explanation), and a NASA Fact Sheet about CERES are also available.

There are a number of CERES instruments flown in different orbits to obtain measurements over the entire globe. The first CERES instrument was launched on Thanksgiving Day, 1997. It was carried to orbit on a Japanese rocket as part of the Tropical Rainfall Measuring Mission (TRMM) spacecraft. You can see an animation of some early results from CERES on TRMM, which shows how the instrument measures Scene Type over the course of a day.

The second and third CERES instruments were launched on December 18,1999. These were carried to orbit out of Vandenberg Air Force Base, California, on the Terra spacecraft. Terra is the flagship of the Earth Observing System (EOS), a major international program to monitor climate and environmental change on Earth over the next 15 years. Part of a series of EOS satellites, Terra will enable new research into the ways that Earth's lands, oceans, air, ice, and life function as a total environmental system.

The fourth and fifth CERES instruments are aboard the Aqua spacecraft, which was launched on May 4, 2002. As its name indicates, this part of the Earth Observing System is focused on looking at water in the Earth system.

Follow this link for an introduction to all the satellites CERES is currently scheduled to fly on.

Why do we observe clouds?

Clouds are powerful agents of global change. They affect the overall temperature or energy balance of the Earth and play a large role in controlling the planet's long-term climate.

To understand the impact of clouds over time, satellites measure the planet's clouds and energy from space. Data from NASA's ERBE and CERES satellite instruments, for example, have made and continue to make significant contributions to the understanding of clouds.