Earth Observations

Satellites provide the potential for observing changes of the Earth system on a global scale. A major task at GISS is to define which satellite observations are needed in the 1990s and to study how satellite data relates to and supports data acquired using more conventional techniques. Satellite observations are analyzed to obtain information on the Earth's surface, atmosphere and, especially, global cloud systems.

Clouds are a great source of uncertainty in predicting future climate. As the climate warms, will it be more cloudy or less? Clouds are potentially the most powerful feedback mechanism in the climate system, but we are not yet even certain whether they are a positive feedback which will enchance future greenhouse warming, or a negative feedback. The crucial and ambiguous role of clouds in the climate system is a result of the fact that clouds principally control the albedo of the Earth (the fraction of sunlight reflected to space) and at the same time strongly influence the amount of infrared (heat) radiation emitted by the Earth to space.

Related Research Groups and Projects

• International Satellite Cloud Climatology Project (ISCCP)
• GEWEX Cloud System Study Data Integration for Model Evaluation (GCSS-DIME)
• Global Aerosol Climatology Project (GACP)
• GISS Surface Temperature Analysis (GISTEMP)

News and Science Briefs

January 2006:
2005 Was Warmest Year in Over a Century

January 2005:
NASA Scientist Wins AMS Award

February 2003:
NASA Goes On-Line with Extra-Tropical Storm Tracks Atlas

January 2002: Fewer Clouds Found In Tropics

November 2001:
Satellites Shed Light on a Warmer World

December 2000:
Clouds and Climate Change: The Thick and Thin of It

May 1998:
Comparing Temperatures from Different Monthly-Mean Datasets

March 1998:
A Common Sense Climate Index: Is Climate Changing Noticeably?

February 1998:
Global Variations in Cloud Water Droplet Concentrations