We describe a continuous-flow analysis (CFA) method to measure Δ¹⁷O by laser spectroscopy, and we show that centimeter-scale information can be measured reliably in ice cores by this method. We present seasonally resolved Δ¹⁷O data from Greenland and demonstrate that the measurement precision is not reduced by the CFA process. Our results encourage the development and use of CFA methods for Δ¹⁷O, and they identify calibration strategies as a target for method improvement.

A high-resolution infrared hygrometer (FIRH) was adapted to measure humidity and its rapid fluctuations in turbulence inside a moist-air wind tunnel LACIS-T where two air streams of different temperature and humidity are mixed. The measurement was achieved from outside the tunnel through its glass windows and provided an agreement with a reference dew-point hygrometer placed inside. The characterization of humidity complements previous investigations of velocity and temperature fields.

The measurement of temperature in the free atmosphere is of significance for weather prediction and climate monitoring. Radiosondes are used to measure essential climate variables in upper air. Herein, an upper-air simulator is developed, and its performance is evaluated to improve the measurement accuracy of radiosondes by reproducing the environments that may be encountered by radiosondes. The paper presents a methodology to correct the main source of error for the radiosonde measurements.

Heating by solar radiation is the dominant error source for daytime temperature measurements by radiosondes. This paper describes a new laboratory setup (SISTER) to characterise this radiation error for pressures and ventilation speeds that are typical for the conditions between the surface and 35 km altitude. This characterisation is the basis for the radiation correction that is applied in the GRUAN data processing for the RS41 radiosonde. The GRUAN data product is compared to that of Vaisala.

A model was developed to quantitatively describe the dynamics, in terms of vapor-phase water concentration and isotope ratios, of nanoliter-droplet evaporation at the end of a syringe needle. Such a low humidity generator can be used to calibrate laser-based water isotope analyzers, e.g., in Antarctica. We show that modeling of experimental data constrains isotope fractionation factors and the evaporation rate to physically realistic values in good agreement with available literature values.