HFE/SKYRAD/M1 - IRT bias

The sky temperatures exhibited a positive bias compared to AERI, especially when < 230K. 
This is indicative of an incorrect emissivity setting (to compensate for the gold mirror) 
or a poor calibration. A similar problem with the same instrument occurred during the FKB 
deployment that was attributed to water vapor.

• Sky Infra Red Temperature Maxima(sky_ir_temp_max)
• Sky Infra-Red Temperature(sky_ir_temp)
• Sky Infra-Red Temperature Minima(sky_ir_temp_min)