CWOP Solar Radiation Search Tool
In addition to sending weather data, about one fifth of active CWOP members located worldwide send solar radiation 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 and then on "Introduction" for information on Solar Radiation. NOAA operates the SURFRAD Network with these Eppley Precision Spectral Pyranometers (PSP) to monitor solar radiation at seven sites around the country. The downwelling solar radiation data from these sites are available here to compare with CWOP member solar radiation data. The NOAA data here 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 a SRC ID) and date 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 eight nearest other solar radiation producing stations. The second, a comma separated variable (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. To save these CSV listings, just do: ctrl-A (for all), ctrl-C (for copy to clipboard), then open a text editor (like Notepad) and do ctrl-V (for view) and then save the file as filename.csv to have a file that can be opened directly by a spread sheet program like Excel or Google Docs. Then it is easy to make a comparison plot and location plot. You can see the locations of the stations on a map by copy and paste from the first row of the CSV file into a findU statement, like this. You will have to zoom out or pan to see all of the stations. Other examples of data comparison are in a 1.5 Mbyte Powerpoint here. 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. Also note that times are not checked, so station clock errors can cause time shifts in the graphs as shown here. Use of Google Docs allows easy sharing of results and collaboration by different station operators to produce joint results.