A method to improve the accuracy of continuous measuring of vertical profiles of temperature and water vapor density by means of a ground-based microwave radiometer

Many of the meteorological phenomena occurring at meso-gamma require observations sufficiently close together in time and space. The multichannel microwave radiometer (MMWR) provides continuous temperature and humidity profiles. We demonstrate a method for profile bias correction that significantly improves vertical temperature (T) and water vapor density (delta wv) profile accuracy. We compared MMWR temperature (TRD) and humidity (delta wvRD) profiles during winter in the Sierra of Guadarrama (Madrid) at 1150 m altitude with thousands of radiosonde temperature (TRW) and humidity (delta wvRW) soundings from a launch site at 610 m altitude and 50 km distance. In spite of relatively large horizontal and vertical separation between the two sites, sounding differences above the boundary layer are comparable to observation error typically assigned to radiosonde soundings when they are assimilated into numerical weather models. Systematic bias between the paired values of TRW and TRD and delta wvRW and delta wvRD ranges from 0.2 to 1.2 K and 0.05 to 0.5 g m(-3). This bias can be removed using a corrector function that is applied at each T and delta wv level. Using this method, the bias for both variables is reduced to insignificant levels and their accuracy is significantly improved. (C) 2012 Elsevier B.V. All rights reserved.