Pub. date: 2008 | Online Pub. Date: April 25, 2008 | DOI: 10.4135/9781412963893 | Print ISBN: 9781412958783 | Online ISBN: 9781412963893| Publisher:SAGE Publications, Inc.About this encyclopedia
Nilton O. Renno
INCREASES IN SURFACE and tropospheric temperatures produce changes in cloud properties that, in turn, produce changes in temperature. This effect is known as cloud feedback. Cloud feedback has been identified by the United Nations Intergovernmental Panel on Climate Change (IPCC) as one of the most uncertain processes in climate models. Cloud particles (hydrometers) affect both thermal and solar radiation. Cloud particle size and concentration are strongly-affected by updraft velocity, humidity, temperature, and cloud nuclei concentration. In addition, the lifetime of cloud particles depends on the humidity of the ambient air. Thus, cloud properties and coverage are sensitive to climate change. Clouds produce extremely complex climate feedbacks that lead to large uncertainty in climate simulations because cloud processes are not well understood. Clouds cool the Earth by scattering solar radiation and increasing the amount of solar radiation returned to space. That is, clouds increase ...