Evaluation of humidity correction methods for Vaisala RS92 tropical sounding data

For example, in daytime soundings the relative RH correction increases from a few percent for temperatures >0°C to 20%-40% between 100 and 200 hPa. Comparison of corrected RH vertical profiles show only small differences (on the order of a few percent or less at any given level) between the DigiCORA and GRUAN algorithms, such that these corrections are considered to be statistically consistent at most levels. In evaluating corrected humidity data with independent estimates of total precipitable water (TPW), good agreement was found at all sites between corrected sounding and ground-based microwave radiometer (MWR) estimates of TPW with mean differences ≤0.9 mm (or <2%), which is well within the uncertainty of these measurements.

Overall, the correction algorithms examined herein perform well over a wide range of tropical moisture conditions.