Development of a Radiometer-Sonde for Simultaneously Measuring the Downward and Upward Broadband Fluxes of Shortwave and Longwave Radiation

Abstract

We have developed a disposable type of radiometer-sonde for independently measuring the downward and upward broadband fluxes of solar and terrestrial radiation with a pair of up-looking and downlooking shortwave (SW) and longwave (LW) radiometers. The radiometer-sonde contains a built-in rawinsonde for simultaneously measuring air-temperature, humidity and wind profiles. The paper outlines the state-of-the-art of the radiometer-sonde, and discusses its performance. We have investigated such characteristics as temperature dependence, linearity, and transitional thermal effects of the SW radiometers, as well as transitional thermal effects of the LW radiometers through laboratory experiments and sonde-launching tests. Further, we have tested the practical performance of the radiometer-sonde for several cases of clear skies. The measured flux profiles were compared with those computed for modeled atmospheres. The developed radiometer-sondes have proved their adequate performance to simultaneously measure the radiative flux profiles and the atmospheric profiles with enough accuracy to detect radiative effects of aerosols (SW radiometers) and water vapor (LW radiometers) in the lower troposphere. It is also suggested that the SL radiometer-sondes will be also effective for measuring the radiative flux profiles in high-level ice-clouds with stronger radiative effects.