AWR/SKYRAD/M1 - Heater not operating

The IRT did not measure sky temperature correctly when the ambient
the temperature was below approximately -25C, because the IRT heater was not operating, 
and due to frost depositing on the mirror and subsequent cleaning with warm ethanol.

Use data with caution

• Sky Infra-Red Temperature Minima(sky_ir_temp_min)
• Sky infrared temperature, standard deviation(sky_ir_temp_std)
• Sky Infra Red Temperature Maxima(sky_ir_temp_max)
• Sky Infra-Red Temperature(sky_ir_temp)

• Instantaneous Sky/Cloud Infrared(inst_sky_ir_signal)