Historical Sunshine and Cloud Data in the United States, CDIAC NDP-021/R1Entry ID: CDIAC_NDP21
Abstract: This package contains monthly sunshine data from 240 U.S. stations (including Puerto Rico and nine Pacific Islands) and monthly cloud amount data from 197 U.S. stations. The longest periods of record are 1891 through 1987 for the sunshine data and 1871 through 1987 for the cloud data.The sunshine data were derived from measurements taken by a variety of sunshine-recording instruments. The cloud ... data were derived from land-based estimates of fractional cloud amount, which were made with observation practices that have varies during the period of record.
The sunshine data include monthly and annual total hours of recorded sunshine, monthly and annual maximum possible hours of sunshine, monthly and annual percentages of possible sunshine (hours recorded/hours possible), and dates of use for recorders at the stations. The cloud data contain monthly and annual cloud amount (in percent of sky cover) and sample listings of the total monthly and annual sunshine measurements, maximum possible monthly and annual sunshine measurements, and the percentages of monthly and annual sunshine (measured/maximum possible).
Sunshine duration is considered to be the time between sunrise and sunset, assuming a smooth, spherical earth. Sunrise and sunset are considered to be when the sun's upper disc appears just above the horizon in the morning and disappears below the horizon in the evening. On a smooth, spherical earth, possible sunshine duration varies only with latitude and time of year.
Sunshine data for 240 U.S. stations (including Puerto Rico and islands in the Pacific) are presented for the years 1891-1984. The periods of record of monthly and annual total hours of sunshine vary widely from station to station. Many of the stations have discontinuous sampling periods and only 15 stations have periods of records greater than 90 years. However, 185 stations have periods of record equal to or greater than 30 years.
Maximum possible sunshine values for the 240 stations recording network range from a minimum of 4,418 hours at the most southern station (San Juan, Puerto Rico) to a maximum of 4,591 hours at the most northern station (Fairbanks Alaska). The highest annual sunshine value ever recorded in the U.S. was at Yuma, Arizona, with 4,272 hours in 1958 (96%) and the lowest was at Mt. Washington, New Hampshire, with 1,181 hours in 1943 (26%).
All CDIAC numerical data packages include copies of pertinent literature discussing the data, summaries discussing the background, source and scope of the data, as well as applications limitations and restrictions of the data. This data set also resides on the CDIAC CD-ROM which contains many other CDIAC data sets.
CDIAC has provided an anonymous FTP area to all data files, retrieval codes, and descriptive files for the NDP's that are presently available. The FTP address is ftp://cdiac.esd.ornl.gov
The NDP-021/R1 data set is located in CDIAC's anonymous FTP in pub/ndp021r1. All files are compressed (UNIX) ASCII text files. All the data bases provided in this area are fully documented.
Data Set Citation
Start Date: 1891-01-01Stop Date: 1987-12-31
Temporal Resolution: Monthly
Temporal Resolution Range: Monthly - < Annual
ISO Topic Category
Distribution Media: on-line (FTP)
National Climatic Data Center Global Climate Laboratory Federal Building 151 Patton Avenue
Province or State: NC
Postal Code: 28801-5001
Climate Services Branch National Climatic Data Center Room 468 151 Patton Avenue
Province or State: North Carolina
Postal Code: 28801-5001
Role: TECHNICAL CONTACT
Fax: (865) 574-2232
Carbon Dioxide Information Analysis Center (CDIAC) Oak Ridge National Laboratory P.O.. Box 2008
City: OAK RIDGE
Province or State: TENNESSEE
Postal Code: 37831-6335
Doehring, F. and T. Karl (1981), A history of sunshine data in the United States 1891-1980, No. 2-2, National Climatic Data Center, Asheville, North Carolina
P. M. Steurer and T. R. Karl (1991), Historical Sunshine and Cloud Data in the United States (revised 1991), doi:10.3334/CDIAC/cli.ndp021, http://cdiac.ornl.gov/ndps/ndp021.html
Creation and Review Dates
Last DIF Revision Date: 2011-09-30