FKB/SKYRAD/M1 - Instrument setup incorrect data

FKB station initial setup and configuration - all radiometer data before the end date of 
this time range is suspect. If this data is needed refer to DQ flags and manual assessment 
to determine if data is usable.

• down_long_hemisp2_min
• inst_down_long_hemisp1_case_temp
• East longitude(lon)
• sky_ir_temp_std
• down_long_hemisp1_std
• down_long_hemisp1_max
• down_long_hemisp1_min
• inst_down_long_hemisp1_dome_temp
• sky_ir_temp_min
• Irradiance, shortwave, downwelling, hemispheric, pyranometer, mifkba(down_short_hemisp_min)
• short_direct_normal_std
• down_short_hemisp_std
• base_time
• Downwelling Shortwave Hemispheric Irradiance, Pyranometer, Maxima(down_short_hemisp_max)
• Altitude above mean sea level(alt)
• down_long_hemisp2_max
• Downwelling shortwave hemispheric irradiance, pyranometer(down_short_hemisp)
• inst_down_long_hemisp1_tp
• logger_temp
• down_long_hemisp2_std
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer1(down_long_hemisp1)
• down_short_diffuse_hemisp_std
• vBatt
• Irradiance, shortwave, downwelling, diffuse, hemispheric, pyranometer(down_short_diffuse_hemisp)
• Downwelling Longwave Hemispheric Irradiance, Shaded Pyrgeometer2(down_long_hemisp2)
• Irradiance, shortwave, direct normal, pyrheliometer, mifkba(short_direct_normal_min)
• inst_down_long_hemisp2_case_temp
• time_offset
• Shortwave Direct Normal Irradiance, Pyrheliometer, Maxima(short_direct_normal_max)
• North latitude(lat)
• sky_ir_temp_max
• inst_down_long_hemisp2_tp
• time
• Sky infrared temperature(sky_ir_temp)
• Shortwave Direct Normal Irradiance(short_direct_normal)
• Irradiance, shortwave, downwelling, diffuse, hemispheric, pyranometer, maxima(down_short_diffuse_hemisp_max)
• Irradiance, shortwave, downwelling, diffuse, hemispheric, pyranometer, minima(down_short_diffuse_hemisp_min)
• inst_down_long_hemisp2_dome_temp

FKB/SKYRAD/M1 - IRT bias

On several days (especially in April, September, and December), the sky temperature 
measurement from the IRT exhibited a positive bias from the AERI measurement from about 20:00 
to 07:00. This diurnal variation is highly correlated with the measurement of relative 
humidity so was most-likely due to the contribution of the temperature of water vapor, fog, 
and/or condensation on the lens and/or mirror.

• Sky infrared temperature(sky_ir_temp)
• sky_ir_temp_min
• sky_ir_temp_max

FKB/SKYRAD/M1 - IRT bias

Measurements of sky temperature, especially those <250K, were positively biased compared 
with AERI because there was no compensation for the reflectivity of the gold mirror. The 
problem was corrected by changing the IRT emissivity from 1.000 to 0.987.

Use sky temperature measurements less than 230K with caution. Biases as large as 30K have 
been observed when the actual temperature, as measured by AERI, is less than 210 K.

• Sky infrared temperature(sky_ir_temp)
• sky_ir_temp_min
• sky_ir_temp_max