SGP/THWAPS/B6 - Minor biases in humidity and saturation vapor pressure
The THWAPS humidity sensor output was scaled so that the instrument output voltage range (0-1VDC) represented 0-100 %RH. Comparisons with the co-located chilled mirror sensor at the CF suggested that the THWAPS RH sensor was reading artifically low at high humidities because of this 100 %RH maximum. The scaling of the system was changed so that 0-1 VDC now represents 0-110 %RH. This resulted in a slight loss of precision in the measurements, but since the RH measurement is only accurate to 2-3 %RH at best, this isn't a significant problem. The saturation vapor correction when temps are below 0C contained an error in the multiplier. The incorrect multiplier only equates to an error of 0.01 kPa which is less than the stated uncertainty of the measurement (+/- 0.035 kPa).
Data should be largely unaffected by the changes made.