On 18 Oct 2006, a thermistor that measures the temperature of the blackbody support
structure failed, resulting in erroneously high values. This measurement, which is captured by
the field "BBsupportStructureTemp", provides the temperature of the radiance that is
reflected into the blackbody (i.e., captured by the field "calibrationAmbientTemp"), and
thus the calibrated radiance (the field "mean_rad") was incorrect and outside the ARM
specification that the AERI data should be absolutely calibrated to within 1% of the ambient
radiance. The broken thermistor was fixed on 22 Nov 2006.
Fortunately, since the emissivity of the blackbodies is so high, absolute accuracy of the
calibrationAmbientTemp is not required but should be within a few degrees. The radiance
data have been recalibrated using the ambient blackbody temperature (the field
"calibrationCBBtemp") as a surrogate of the calibrationAmbientTemp. Historically, the
calibrationAmbientTemp and calibrationCBBtemp measurements have been within 1-2 deg. As a result of
this recalibration, the radiance data are now absolutely calibrated to better than 1%.