Comparing radiosonde and COSMIC atmospheric profile data to quantify differences among radiosonde types and the effects of imperfect collocation on comparison statistics

The first is to quantify the error characteristics of 12 radiosonde types flown in the global operational network, as a function of height and for both day and nighttime observations, for each of the three variables.

The second is to determine the effects of imperfect temporal and spatial collocation on the radiosonde-COSMIC differences, for application to the general problem of satellite calibration and validation using in situ sounding data. Statistical analyses of the comparisons reveal differences among radiosonde types in refractivity, relative humidity, and radiation-corrected temperature data. Most of the radiosonde types show a dry bias, particularly in the upper troposphere, with the bias in daytime drier than in nighttime.