NOAA NCEI has acquired these legacy data sets from multiple sources over many decades. The data presented here are provided, ‘as is,’ and in most cases the linked documentation is the entirety of available information at NCEI. Newer versions of some of these data sets and models may be available elsewhere. In some cases, older data may also be found in the Space Weather Legacy Print Publications. The directories are ftp folders that you must paste into a file explorer to access. Other locations for TSI data include LASP Interactive Solar Irradiance Data Center and Data.gov.
Questions and comments may be directed to ncei.info@noaa.gov.
About
Total Solar Irradiance (TSI) Composite Database is compiled from many satellite TSI data collected from 1978 to present day by Claus Frohlich and Judith Lean, data format. Radiometrically, the composite is based on the Active Cavity Radiometer Irradiance Monitor (ACRIM-I and II) records collected before the start of the ACRIM-I measurements in1980, during the spin mode of Solar Maximum Mission (SMM), and bridging the gap between ACRIM-I and II. Corrected data are inserted by shifting the level to fit the corresponding ACRIM data over an overlapping period of 250 days on each side of the ACRIM sets.
In early 1996, the Variability of Solar Irradiance and Gravity Oscillations (VIRGO) data collection satellite took over and shifted to agree with ACRIM-II. Finally the composite records are adjusted via ACRIM-II to SARR (Space Absolute Radiometer Reference) which was introduced by Commelynck et al. (1995) and allows for the comparison of different space experiments. The data from the Earth Radiation Budget Experiment (ERBE) and ACRIM-III, as well as an empirical model, are used for comparisons and for internal consistency checks. See the World Radiation Center for more information.
Data Access
Active Cavity Radiometer Irradiance Monitor (ACRIM)
The Active Cavity Radiometer Irradiance Monitor (ACRIM) measured the total variability of solar irradiance with active cavity radiometer solar monitoring sensors on several satellites. The ACRIM Composite Total Solar Irradiance (TSI) Time Series Database was compiled from many satellite TSI data from 1978-2001 by Richard Willson.
The dataset and related information including plot are in the ACRIM3 Composite. ACRIM 3 was successfully launched on board the NASA ACRIMSAT spacecraft on December 20, 1999. The ACRIM composite time series is constructed from combinations of satellite TSI data sets. NNAA3 uses Nimbus7 ERB and ACRIM1, 2, and 3 results (plot). NNAVA3 replaces the 1996-1998 ACRIM2 results with the two year VIRGO results (plot).
TSI Data from Individual Satellites
NASA Earth Radiation Budget Satellite (ERBS) satellite data October 1984–August 2003
From 1984 to present, total solar irradiance (TSI) values were obtained from the solar monitor on the Earth Radiation Budget Satellite (ERBS) non-scanner instrument. The ERBS solar monitor is an active cavity radiometer, similar in design to the Active Cavity Radiometer Irradiance Monitors (ACRIM) which have flown on the NASA Solar Maximum Mission (SMM), Upper Atmosphere Research Satellite (UARS), and Atmospheric Laboratory for Applications and Science (ATLAS) spacecraft missions. The ERBS satellite was placed into orbit on October 5, 1984, and the solar monitor is still operating properly, after almost 18 years. The measurement precision is about 0.01 percent, while the accuracy is 0.2 percent. At least once every 14 days, the Sun is observed by the monitor. The averaged irradiance values represent an almost instantaneous level, and not a daily average. ERBS satellite bi-weekly database.
NASA NIMBUS satellite data November 16, 1978–December 13, 1993
From 1978 to 1993, Total Solar Irradiance (TSI) values were obtained from the solar monitor on the NASA NIMBUS (named for the Latin word for raincloud) non-scanner instrument. The NIMBUS solar monitor is an active cavity radiometer, similar in design to the Active Cavity Radiometer Irradiance Monitors (ACRIM) which have flown on the NASA Solar Maximum Mission (SMM), Upper Atmosphere Research Satellite (UARS), and Atmospheric Laboratory for Applications and Science (ATLAS) spacecraft missions. The paper "The Nimbus-7 Solar Total Irradiance: A new Algorithm for its Deviation" by D.V. Hoyt, H.L. Kyle, J.R. Hickey, and R.H. Maschoff (JGR, vol 97, pp 51-63) describes the methodology used to reduce the data. NIMBUS satellite bi-weekly database in x-y plottable format.
NOAA 9 and 10 satellite data January 23, 1985–December 20, 1989
From 1985 to 1989, TSI values were obtained from the solar monitor on the NOAA9 and NOAA 10 non-scanner instruments. The NOAA solar monitor is an active cavity radiometer, similar in design to the Active Cavity Radiometer Irradiance Monitors (ACRIM) which have flown on the NASA Solar Maximum Mission (SMM), Upper Atmosphere Research Satellite (UARS), and Atmospheric Laboratory for Applications and Science (ATLAS) spacecraft missions.
NASA Solar Maximum Mission (SMM) satellite data February 16, 1980–June 1, 1989
From 1980 to 1989, TSI values were obtained from the solar monitor on the SMM non-scanner instruments. The SMM solar monitor is an active cavity radiometer, similar in design to the Active Cavity Radiometer Irradiance Monitors (ACRIM) which have flown on the NASA Solar Maximum Mission (SMM), Upper Atmosphere Research Satellite (UARS), and Atmospheric Laboratory for Applications and Science (ATLAS) spacecraft missions.
SOHO VIRGO, v2 satellite data February 16, 1980–June 1, 1989
From 1980 to 1989, TSI values were obtained from the solar monitor on the SMM non-scanner instruments. The SMM solar monitor is an active cavity radiometer, similar in design to the Active Cavity Radiometer Irradiance Monitors (ACRIM) which have flown on the NASA Solar Maximum Mission (SMM), Upper Atmosphere Research Satellite (UARS), and Atmospheric Laboratory for Applications and Science (ATLAS) spacecraft missions.
- SOHO VIRGO v2 satellite daily database (txt) in x-y plottable format
- SOHO VIRGO v2 satellite plot of daily database 1996–1999
NASA Upper Atmosphere Research Satellite (UARS) Active Cavity Radiometer Irradiance Monitor II Experiment (ACRIM II) TSI satellite data October 4, 1991–December 31, 1997
The second Active Cavity Radiometer Irradiance Monitor experiment (ACRIM II) was launched in September 1991 as part of the science payload of the Upper Atmosphere Research Satellite (UARS). The variations on solar rotational and active region time scales are clearly seen. The large, short-term decreases are caused by the TSI blocking effect of sunspots in magnetically active regions as they rotate through our view from Earth. The peaks of TSI preceding and following these sunspot "dips" are caused by the faculae of solar active regions whose larger areal extent causes them to be seen first as the region rotates on our side of the sun and last as they rotate over the opposite solar limb. The downward trend through the 1991-1997 period is similar in slope and amplitude to that observed by ACRIM I during the declining phase of solar cycle 21. From the peak of solar cycle 21 to its minimum, the TSI decreased by about 0.08 percent. It appears likely from the ACRIM II results thus far that the cycle 22-23 minimum in TSI will occur during 1997, near the average solar cycle period of about 11 years after the cycle 21-22 minimum, and with a similar decrease relative to the maximum of cycle 22 in the 1990-1991 period. NASA UARS satellite daily database.
Dr. John C. Arvesen's Solar Spectral Irradiance at the Top of the Atmosphere UV to Visible (200–2495 nm)
NASA research aircraft database including descriptive text. Results are presented of an experiment to determine extraterrestrial solar spectral irradiance at Earth's mean solar distance within the 300-2500 nm wavelength region. Spectroradiometric measurements were performed during eleven research flights on board a NASA CV-990 aircraft at altitudes between 11.6 km and 12.5 km. Precision of the measurements was better than +/- 1 percent. Absolute accuracy of the resultant extraterrestrial solar spectral irradiance is about +/-3 percent over most of the measurement range. A listing of results is presented at intervals varying from 0.1 nm throughout most of the UV-visible Fraunhofer region to 5 nm in the continuum region of the infrared. Additionally, a listing of solar spectral irradiance, smoothed over the detailed Fraunhofer structure, is presented for engineering use.
Charles Greeley Abbot Solar Constant Database 1902–1954
Descriptive text and data format
The Smithsonian Astrophysical Observatory (APO) gathered solar constant data during at least 49 years of solar monitoring. The solar constant is the total amount of energy received from the sun per unit time per unit area exposed normally to the Sun's rays at the average Sun-Earth distance and outside of Earth's atmosphere. The purpose of this APO project was to determine an accurate value for this energy flux and to determine whether or not the Sun's total energy output is indeed constant in time.
Notwithstanding all of the shortcomings and controversy inherent in the data, this program is the longest and most carefully conducted solar radiation program in the 20th century. Dr. Vernon Derr estimated that to fully understand and correct the database, the research efforts of two qualified scientists studying the data for approximately two years would be needed. The 47 data files are available via the ftp site.