Solar Influences on Global Change

Solar Influences on Global Change Data (All ftp)

Solar Influences on Global Change has emerged as an interesting field of study, especially since the NIMBUS satellite documented the inconstancy of the solar constant. The National Geophysical Data Center (NGDC) is compiling a comprehensive solar database for use in global change models. Solar radiation drives the weather machine. Variations in the Sun's radiative output impact the Earth's climate. The NOAA Climate Analysis Center currently uses solar cycle data in their U.S.seasonal winter forecasts. Spacecraft observations show the Sun's output varied by 0.1% during the past 11-year solar activity cycle, producing a climate forcing of 0.24 W/m2. Climate forcing by increasing greenhouse gases from 1980 to 1986 was about 0.25 W/m2. Global change models need to discern between variations caused by anthropogenic and natural occurrences to provide a sound scientific basis for policy making on global change issues. The NGDC archives are part of a cross-disciplinary effort within NOAA to link observed changes on the Sun with terrestrial climate.

With the advent of total solar irradiance satellite measurements since 1978, it is now documented that the amount of energy from the Sun varies over decadal time scales. The Sun supplies the energy for the Earth's system heat budget. The major components that affect this heat budget are a.) changes in the Earth's orbit, b.) internal processes (such as cloudiness, ice cover, anthropogenic effects, etc.), and c.) variations in solar activity. Because the Earth's climate is changing, it is critical to understand the contributions of each component and take action when necessary to curb possible negative effects we might control. A good example of this kind of action is the worldwide effort to reduce the amount of chlorofluorocarbons (CFCs) emitted by man. Climate variability is a major issue and our understanding is still uncertain.

• A descriptive text Databases for Global Change Models is available that describes the various databases that NGDC holds and how they might pertain to Global Change. The National Research Council report "Solar Influences on Global Change" is an in-depth study of the effects of solar variations on our climate.

• The vorticity area index (VAI) is a combined index of cyclonic activity at a given atmospheric pressure level. It is defined as the total surface area where the absolute vorticity exceeds 20x10**-5 per second plus the total surface area where the absolute vorticity exceeds 24x10**-5 per second. The VAI values given in the list are for 0000 UT (April 1955-1978) and 1200 UT (1946-1978) and are in the units of 10**5 km-squared. They are derived from the 500 mb height analysis records for the Northern Hemisphere above N10 latitude obtained from the U.S. National Meteorological Center. Missing VAI values denote missing records and are blanks in the database.
  • Description of the data and file format (text)
    • Daily values 1946-1978

• Data source: MOHSST6. Parker, D.E., Folland, C.K. and Jackson, M.: Marine surface temperature: observed variations and data requirements, CLIMATIC CHANGE, Vol. 31, pp. 559-600 (1995). The data begin in 1856 and continue through 1995. Values are in degrees Celsius.
  • Monthly averages in deg C
  • Descriptive text