According to the results of a recent study by the Jet Propulsion Laboratory (JPL), there has been a decrease of a tenth of a percent in the total amount of solar energy reaching the earth over the 18-month period from February 1980 to August 1981. This conclusion is based on data obtained from the Active Cavity Radiometer Irradiance Monitor (ACRIM) that is incorporated onto the Solar Maximum Mission satellite. The results are significant for studies of the physics and geophysics of the sun and could have implications for short- and long-term weather patterns on the earth's surface.
The ACRIM has a precision of better than 10 4, whereas the uncertainties in the best earth-based observations are on the order of 1% to 2%. The JPL group conducting the study suggests that the decrease in the sun's energy may even have been a factor in this year's unusually harsh winter.