Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

Solar records: the Wolf sunspot index and umbral/penumbral ratio

Technical Report ·
OSTI ID:6834487
Annual Wolf sunspot numbers and umbral/penumbral (U/P) ratios are given for the period 1875-1981. The data are summarized from daily values and are as accurate a reconstruction as can be presently made.
Research Organization:
National Oceanic and Atmospheric Administration, Boulder, CO (USA)
DOE Contract Number:
AC05-84OR21400
OSTI ID:
6834487
Report Number(s):
NDP-014
Country of Publication:
United States
Language:
English