CWOP Solar Radiation DataAbout one fifth of active CWOP members send solar radiation data along with other weather data and most use this Solar Radiation Sensor. Each of these Davis sensors has been "calibrated against a secondary standard which is calibrated periodically against an Eppley Precision Spectral Pyranometer in natural daylight". Click here for information on solar radiation measurements. The CWOP solar radiation data are acquired by findu.com and available for viewing here, where call is station ID in findU, xsize and ysize determine size of the graph, and last is the number of previous hours covered on the x axis.
NOAA operates the SurfRad Network with these Eppley Precision Spectral Pyranometers to monitor solar radiation at seven sites around the US 48-state area. The downwelling solar radiation data from these sites are available to compare with CWOP solar radiation data. The NOAA SurfRad data have IDs that start with the letters of "Surf Rad Calibration (SRC...) and are: SRCBON Bondville, IL; SRCTBL Boulder, CO; SRCDRA Desert Rock, NV; SRCFPK Fort Peck, MT; SRCGWN Goodwin Creek, MS; SRCPSU Penn State, PA; and SRCSXF Sioux Falls, SD.
This tool will accept a CWOP ID (or SRC ID) and date in the boxes below, and then return one of three data sets. The first, a listing of the received raw packets from that station for the specified date and a listing of the selected number of nearby solar stations. The second, a CSV listing of the time, solar radiation, wind, temperature values for a single station. The third, a CSV listing of time and solar radiation for between one and twenty (closest first) stations.
The units for time are decimal UTC hours; for solar radiation, Watts per square meter; for wind, miles per hour; and for temperature, degrees F. Note that only packets with non-zero values of solar radiation are listed. Entering ? for Call Sign and a recent date below will return a list of stations sending solar radiation data on that day.
Solar Radiation Raw Data ArchiveAll of the solar radiation data received by CWOP since 2009 have been archived. This collection is described in Six Years of the Solar Radiation Data Archive: Citizen Weather Observer Program which summarizes the holdings, now comprising more than a quarter billion reports. Those reports have been collected into an Amazon Web Services database as described by Paper 12.1 in the Innovative Measurements Session at the 2016 AMS Annual Meeting. There is a related poster from the 31st Conference on Climate Variability and Change presented at the 2018 AMS Annual Meeting. The raw data packets used to get the solar radiation data in the archive are available for download as daily text files compressed by gzip. After download, they have to be ungzipped to be viewed. The report linked above has a script for downloading the files. The NOAA SurfRad data discussed above are also included in these files.