Irradiance Measurement Biasing by Infrared Cooling Errors for the Eppley PSP

Global solar irradiance measurements made using Eppley Precision Pyranometers (PSP) can be biased by IR cooling errors. During the New England high resolution temperature and forecasting experiment (NEHRTP-2004) the NOAA Environmental Technology Laboratory made side-by-side comparisons of the global solar irradiance measured using PSPs and by combining separate direct and diffuse measurements utilizing pyroheliometers and 8-48 Black and White pyranometers at Concord, NH and Plymouth, MA. These measurements allowed us to quantify and correct the magnitude of the thermal offset error in the PSPs, and allowed us to use the global PSP's during periods when the solar trackers used in the experiment failed.