Bb. Demoz et al., FIELD PERFORMANCE OF A SPINNING-REFLECTOR MICROWAVE RADIOMETER, Journal of atmospheric and oceanic technology, 10(3), 1993, pp. 420-427
In the winter of 1986, two microwave radiometers were operated side by
side at a high-altitude weather observation site in the central Sierr
a Nevada for the purpose of comparing measurements in a variety of amb
ient weather conditions. The instruments continuously recorded measure
ments of vertically integrated water vapor and liquid water during sto
rms affecting the area. One radiometer was designed with a spinning re
flector to shed precipitation particles, while the other radiometer's
reflector was fixed. Temporal records of the data show periods of wet
weather contamination for the fixed reflector radiometer. The absence
(presence) of these contaminated periods is mainly explained by the di
fference in the design of the radiometers. These contaminated periods
led to larger standard deviation in the data from the fixed-reflector
radiometer and lower correlation coefficients between the two instrume
nts. Correlation coefficients of 0.83 for the liquid and 0.68 for the
vapor values were found for the radiometer-radiometer comparisons. Whe
n some of the points suspected of contamination were removed, the cor-
relation coefficients improved to 0.87 and 0.71 for the liquid and vap
or values, respectively. The standard deviations were 0.1 mm and 0. 12
cm for the liquid and vapor channels, respectively, of the spinning r
eflector radiometer. For the fixed-reflector design radiometer, a stan
dard deviation of 0.1 mm for the liquid and 0.26 cm for the vapor was
found. Comparison of radiometer vapor and rawinsonde precipitable wate
r resulted in a correlation coefficient of 0.97 for the spinning-refle
ctor radiometer and 0.8 for the fixed-reflector radiometer.