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Nimbus-7 Earth radiation budget calibration history. Part 1: The solar channelsThe Earth Radiation Budget (ERB) experiment on the Nimbus-7 satellite measured the total solar irradiance plus broadband spectral components on a nearly daily basis from 16 Nov. 1978, until 16 June 1992. Months of additional observations were taken in late 1992 and in 1993. The emphasis is on the electrically self calibrating cavity radiometer, channel 10c, which recorded accurate total solar irradiance measurements over the whole period. The spectral channels did not have inflight calibration adjustment capabilities. These channels can, with some additional corrections, be used for short-term studies (one or two solar rotations - 27 to 60 days), but not for long-term trend analysis. For channel 10c, changing radiometer pointing, the zero offsets, the stability of the gain, the temperature sensitivity, and the influences of other platform instruments are all examined and their effects on the measurements considered. Only the question of relative accuracy (not absolute) is examined. The final channel 10c product is also compared with solar measurements made by independent experiments on other satellites. The Nimbus experiment showed that the mean solar energy was about 0.1 percent (1.4 W/sqm) higher in the excited Sun years of 1979 and 1991 than in the quiet Sun years of 1985 and 1986. The error analysis indicated that the measured long-term trends may be as accurate as +/- 0.005 percent. The worse-case error estimate is +/- 0.03 percent.
Document ID
19940009490
Document Type
Other - NASA Reference Publication (RP)
Authors
Kyle, H. Lee (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Hoyt, Douglas V. (Research and Data Systems, Inc. Greenbelt, MD., United States)
Hickey, John R. (Eppley Lab., Inc. Newport, RI., United States)
Maschhoff, Robert H. (Gulton Industries, Inc. Albuquerque, NM., United States)
Vallette, Brenda J. (Research and Data Systems, Inc. Greenbelt, MD., United States)
Date Acquired
September 6, 2013
Publication Date
September 1, 1993
Subject Category
SOLAR PHYSICS
Report/Patent Number
NASA-RP-1316
REPT-93B00110
NAS 1.61:1316
Funding Number(s)
PROJECT: RTOP 665-10-70
CONTRACT_GRANT: NAS5-31331
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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