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GCOS Atmospheric Upper Air ECV
Cloud Properties
- Definition: 1. A visible aggregate of minute water droplets and/or ice particles in the atmosphere above the earth's surface.
Cloud differs from fog only in that the latter is, by definition, close (a few meters) to the earth's surface. Clouds form in the free atmosphere as a result of condensation of water vapor in rising currents of air, or by the evaporation of the lowest stratum of fog. For condensation to occur at a low degree of supersaturation, there must be an abundance of cloud condensation nuclei for water clouds, or ice nuclei for ice-crystal clouds, at temperatures substantially above -40°C. The size of cloud drops varies from one cloud type to another, and within any given cloud there always exists a finite range of sizes. Generally, cloud drops (droplets) range from 1–100 µm in diameter, and hence are very much smaller than raindrops. See cloud classification. 2. Any collection of particulate matter in the atmosphere dense enough to be perceptible to the eye, as a dust cloud or smoke cloud. (from the AMS Glossary of Meteorology)
- Contributing Networks & Status
- International Data Centers and Archives for Atmospheric Upper-Air:
- Coordinating Bodies:
- Satellite Observations
- References:
Data, Metadata, Products and Information Access
[ECV Matrix Main Page] [About the ECV Matrix] [Reference Documents] [Contact] [Updated May 18, 2010]
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Non-satellite or in-situ |
Satellite
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- Clouds and the Earth's Radiant Energy System (CERES) (NASA/ASCD) provides radiometric measurements of the Earth's atmosphere from three broadband channels. The first CERES instrument (PFM) was launched on November 27, 1997 as part of the Tropical Rainfall Measuring Mission (TRMM). Two CERES instruments (FM1 and FM2) were launched into polar orbit on board the EOS flagship Terra on December 18, 1999, and two additional CERES instruments (FM3 and FM4) were launched on board EOS Aqua on May 4, 2002. (data) (metadata) (data documentation) (contact)
- Global Energy and Water Cycle (GEWEX) (WRCP) GEWEX is an integrated program of research, observations, and science activities ultimately leading to the prediction of global and regional climate change. The International GEWEX Project Office (IGPO) is the focal point for the planning and implementation of all GEWEX activities. The goal of GEWEX is to reproduce and predict, by means of suitable models, the variations of the global hydrological regime, its impact on atmospheric and surface dynamics, and variations in regional hydrological processes and water resources and their response to changes in the environment, such as the increase in greenhouse gases. (data) (metadata) (data documentation) (Cloud Assessment Working Group) (GEWEX Cloud System Study (GCSS)) (contact)
- International Satellite Cloud Climatology Project (ISCCP) Global Surface and Atmospheric Radiation Fluxes (NASA/ISCCP) (WRCP)ISCPP was established in 1982 as part of the World Climate Research Programme (WCRP) to collect and analyze satellite radiance measurements to infer the global distribution of clouds, their properties, and their diurnal, seasonal, and interannual variations. Data collection began on 1 July 1983. The resulting datasets and analysis products are being used to improve understanding and modeling of the role of clouds in climate, with the primary focus being the elucidation of the effects of clouds on the radiation balance. These data can also used to support many other cloud studies, including understanding of the hydrological cycle. (data) (metadata) (data documentation) (contact)
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