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Know Your Earth 3.0: AcrimSat
ACRIMSAT banner with Sandy Kwan

About Sandy Kwan

Sandy Kwan of NASA's Jet Propulsion Laboratory is the project manager for ACRIM, which stands for the Active Cavity Radiometer Irradiance Monitor. This instrument measures the total solar irradiance of the sun, which is the total light energy coming from our sun. What makes the instrument active is because it maintains the temperature of its solar sensing cavity slightly hotter than the rest of the instrument at all times, using an automatic electronic system.

About AcrimSat

Artist's concept of AcrimSat

Artist's concept of AcrimSat.
Credit: NASA/JPL
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Launched Dec. 20, 1999, the Active Cavity Radiometer Irradiance Monitor Satellite (AcrimSat) monitors the total amount of the sun's energy reaching Earth. It is this energy, called total solar irradiance, which creates the winds, heats the land and drives ocean currents. Some scientists theorize a significant fraction of Earth's warming may be solar in origin due to small increases in the sun's total energy output since the last century. By measuring incoming solar radiation, climatologists are using AcrimSat to improve their predictions of climate change and global warming over the next century. It wasn't until satellite observations began in late 1978 that scientists even realized that there were variations in the sun's energy.

Additional Links

› AcrimSat mission
› AcrimSat experiments