title: Laboratory calibration of pyrgeometers with known spectral responsivities.
abstract: A methodology is presented to calibrate pyrgeometers measuring atmospheric long-wave radiation, if their spectral dome transmission is known. The new calibration procedure is based on a black-body cavity to retrieve the sensitivity of the pyrgeometer, combined with calculated atmospheric long-wave spectra to determine a correction function in dependence of the integrated atmospheric water vapor to convert Planck radiation spectra to atmospheric long-wave spectra. The methodology was validated with two custom CG4 pyrgeometers with known dome transmissions by a comparison to the World Infrared Standard Group of Pyrgeometers at the World Radiation Center-Infrared Radiometry Section. The responses retrieved using the new laboratory calibration agree to within 1% with the responses determined by a comparison to the WISG, which is well within the uncertainties of both methodologies.
authors.affiliation: Physikalisch-Meteorologisches Observatorium Davos, World Radiation Center, Davos Dorf, Switzerland. julian.groebner@pmodwrc.ch
authors.forename: Julian
authors.initials: J
authors.lastname: Gröbner
authors.forename: Alexander
authors.initials: A
authors.lastname: Los
mesh_terms: D001272:Atmosphere; D002138:Calibration; D004867:Equipment Design; D015233:Models, Statistical; D011874:Radiometry; D012016:Reference Values; D012542:Scattering, Radiation; D013055:Spectrophotometry, Infrared / Q000379:methods; D013696:Temperature; D014867:Water / Q000737:chemistry
chemical_list: D014867:Water