gov.noaa.ngdc.stp.solar:G01350National Geophysical Data Center (comp)1874In 1848 Rudolph Wolf devised a daily method of estimating solar activity by counting the number of individual spots and groups of spots on the face of the sun. Wolf chose to compute his sunspot number by adding 10 times the number of groups to the total count of individual spots, because neither quantity alone completely captured the level of activity. Each daily mean is computed as a weighted average of counts made by a network of cooperating observers in an effort to reduce the influence of personal judgment. Sunspots are optically dark regions in the solar atmosphere of relatively low temperature. They mark areas where the sun's magnetic field has intensified by 1 or 2 powers of 10. The frequency of occurrence of sunspots rises and falls with an 11-year periodicity.Solar Research - Sun's Magnetic Field18000101UnknownUnknownIn workmonthlyNASA/Global Change Master Directory (GCMD) Earth Science KeywordsEARTH SCIENCE > Sun-earth Interactions > Solar Activity > SunspotsUncontrolled KeywordsSolar PhysicsRelative Sunspot CountInternational Sunspot NumberSunspotNASA/GCMD Location KeywordsPhotosphereUncontrolled Location KeywordsSunRestriction Code: otherRestrictions; DOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of CommerceUser Servicesphysical and mailing NOAA/NESDIS/NGDC E/GC 325 Broadway BoulderCO80305-3328(303) 497-6826ngdc.info@noaa.govUnknown 20111117Solar Data ManagerDOC/NOAA/NESDIS/NGDC > National Geophysical Data Center, NESDIS, NOAA, U.S. Department of Commercemailing and physical NOAA/NESDIS/NGDC E/GC2 325 Broadway BoulderCO80305303.497.6133 or 303.497.6323solar.ngdc@noaa.govContent Standard for Digital Geospatial Metadata: Extensions for Remote Sensing MetadataFGDC-STD-012-2002