Clouds create uncertainty in climate models
Image courtesy of NASA
DB: This is Earth and Sky, speaking with Bruce Wielicki, who is an expert on Earth’s clouds.
JB: Wielicki leads a project called CERES, which continuously tracks clouds via satellite. He said clouds are one of the biggest uncertainties in models of global climate change. That’s because clouds are so small. A typical, fast supercomputer running a current generation climate model is probably a hundred times coarser in resolution than a typical puffy cumulus cloud in the real sky.
Bruce Wielicki: What CERES tries to do is tell these models what the clouds are really doing that they can’t resolve, and then the models try to get more and more accurate at simulating what those clouds are doing.
DB: Of the findings so far, he said, the biggest thing they’ve gained is the ability to understand how clouds affect the sun’s energy coming in – and heat either going out or staying near Earth – according to individual cloud type.
Bruce Wielicki: And so we’re trying to sort out, sort of give the climate models much tighter hoops to jump through to prove that they really know how to handle clouds. So that’s been the first big breakthrough.
_JB: He said it’s “kind of a big grey area” as to how accurate the models have to become, with respect to clouds, in order to be good enough to predict climate 100 from now. Our thanks today to NASA:_ explore, discover, understand. We’re Block and Byrd for Earth and Sky.
Bruce Wielicki added:
The other things we’ve been seeing are some of the changes that are going on in the Earth’s energy budget year to year. For example, the total amount of heat the oceans are storing as they warm, because they are warming, varies from year to year. And it looks like it’s actually tied in with how the clouds are changing. So we have an ocean-cloud link now that we’re at the very beginning stages of trying to puzzle out. So that’s one of the other exciting things I think that we’ve seen so far in the data.
Learn more about CERES in Earth & Sky’s interview with Bruce Wielicki.
Visit the CERES home page.
Teachers, find out how your school can help NASA scientists collect data on clouds.
Thanks to:
Bruce Wielicki
Principal Investigator
CERES Project
NASA Langley Research Center
Hampton, VA
Additional Teacher Resources
NASA: CERES: Understanding the Earths Clouds and Climate
The Clouds and the Earths Radiant Energy System (CERES) instrument is one of several scheduled to launch aboard the Earth Observing Systems (EOS) Aqua spacecraft in 2002. Scientists will use observations from the CERES instrument to study the energy exchanged between the Sun; the Earths atmosphere, surface and clouds; and outer space.
NASA: Clouds and the Earths Radiant Energy System
The homepage for the NASA CERES program.
