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Long-Term Total Solar Irradiance (TSI) Variability Trends: 1984-2004The incoming total solar irradiance (TSI), typically referred to as the solar constant, is being studied to identify long-term TSI changes, which may trigger global climate changes. The TSI is normalized to the mean earth-sun distance. Studies of spacecraft TSI data sets confirmed the existence of 0.1 %, long-term TSI variability component with a period of 10 years. The component varied directly with solar magnetic activity associated with recent 10-year sunspot cycles. The 0.1 % TSI variability component is clearly present in the spacecraft data sets from the 1984-2004, Earth Radiation Budget Experiment (ERBE) active cavity radiometer (ACR) solar monitor; 1978-1993, Nimbus-7 HF; 1980-1989, Solar Maximum Mission [SMM] ACRIM; 1991-2004, Upper Atmosphere Research Satellite (UARS) ACRIM; 1996-2003, Solar and Heliospheric Observatory (SOHO)/VIRGO, Space Science (ATLAS), 2000-2004, ACRIMSAT; and 2003-2004 SOlar Radiation and Climate Experiment (SORCE) active cavity radiometer (ACR) missions. From October 1984, through March 2004, the ERBS/ERBE solar monitor was used to produce the longest continuous data set of total solar irradiance (TSI) variability measurements. The solar monitor is located on Shuttle Atmospheric Laboratory for Applications and the NASA Earth Radiation Budget Satellite (ERBS). Maximum TSI values occurred during the 1989-1991, and 1998-2002, time frames; while minimum [quiet sun] TSI levels occurred during 1986 and 1996. Recent ERBS measurements indicate that the TSI is decreasing to forecasted, minimum levels by 2006. Using the discontinuous non-operational Nimbus-7, SMM ACRIM, and UARS ACRIM mission TSI data sets, Wilson and Mordvinor (2003) suggested the existence of an additional long-term TSI variability component, 0.05 %, with a period longer than a decade. Analyses of the ERBS/ERBE data set do not support the Wilson and Mordvinor analyses approach because it used the Nimbus-7 data set which exhibited a significant ACR response shift of 0.7 Wm-2
Document ID
20040139609
Acquisition Source
Langley Research Center
Document Type
Preprint (Draft being sent to journal)
Authors
Lee, Robert Benjamin, III
(NASA Langley Research Center Hampton, VA, United States)
Wilson, Robert S.
(Science Applications International Corp. Hampton, VA, United States)
Thomas, Susan
(Science Applications International Corp. Hampton, VA, United States)
Date Acquired
August 22, 2013
Publication Date
January 1, 2004
Subject Category
Solar Physics
Report/Patent Number
P6.31
Meeting Information
Meeting: American Meteorological Society 13th Conference on Satellite Meteorology and Oceanography
Location: Norfolk, VA
Country: United States
Start Date: September 20, 2004
End Date: September 24, 2004
Sponsors: American Meteorological Society
Funding Number(s)
OTHER: 229-01-02
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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