Changing Global Cloudiness

Terra and Cloud Observations
NASA's Terra satellite will observe how clouds interact with Earth's energy budget on a global scale, as well as provide detailed measurements of clouds' structures and droplet sizes. Four of the five sensors aboard Terra will work together in different combinations to make important new measurements of clouds.

The Moderate-Resolution Imaging Spectroradiometer (MODIS) and Multi-Angle Imaging SpectroRadiometer (MISR) will enable us to view clouds' features at higher resolution-an improvement that will take scientists from the half-mile range available on satellites today, to as sharp as about 800 feet (250 meters.) Both of these instruments take observations at several wavelengths in the electromagnetic spectrum, enabling cloud droplet size measurements, which are critical to understanding the optical and physical properties of clouds.

In addition to an improved "spectral resolution," MODIS takes measurements at several wavelengths in the heat emission spectra of Earth. These measurements will allow scientists to more precisely determine the contributions of clouds to the greenhouse warming of Earth.

With cameras pointed in nine directions, the multi-angle views of the MISR instrument will observe the angles at which sunlight is reflected from clouds. These observations will be critical to new research on the radiative properties of clouds.

For climate-related studies, the Clouds and the Earth's Radiant Energy System (CERES) instrument will help fill gaps in the parts of the solar spectrum that MISR and MODIS cannot see. CERES together with MODIS and MISR will greatly improve understanding of the links between the variability of net incoming sunlight (shortwave radiation) and net outgoing heat (longwave radiation) and its connection to cloud structure and coverage.

The Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) provides very high spatial resolution measurements (50-300 feet [15-90 meters]) at a number of visible and infrared wavelengths. ASTER will complement the other instruments by providing sporadic, high-resolution views at specific targets of interest.

Cloud-related studies made possible by Terra should produce more accurate and comprehensive observations of Earth's cloud cover. These observations are important for developing improved models of Earth's climate, both for seasonal and longer-term climate predictions. Terra's data will give us new insights into how clouds modulate atmospheric and surface temperature, atmospheric humidity, atmospheric and oceanic circulation and precipitation patterns, all of which affect our daily lives in fundamental ways, from recreation to fishing to farming.

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Changing Global Cloudiness
How do Clouds Form?
Clouds and Climate Change
Surface-Based and Satellite Cloud Observations
Terra and Cloud Observations