Errors in Infrared Thermometry and Radiometry

Abstract

This paper describes an error apparently unrecognized among atmospheric scientists engaged in infrared thermometry and radiometry. The error results from multiple reflections between the target environment viewed by a thermometer or radiometer and the background environment. The difference between the sum of this error and other known errors, on the one hand, and only the other known errors, on the other hand, is termed the ?unrecognized error.? Its magnitude and sign are analyzed with respect to the ratio of the background and target temperatures and with respect to the emissivities of the target and the background. The error for thermometry increases as either the target or the background departs from the blackbody condition, and as the background becomes warmer relative to the target. Analogous errors for radiometry are examined with the same results.