The Airborne Hyper-Angular Rainbow Polarimeter (AirHARP) is a new Earth-observing instrument that can provide highly accurate measurements of the atmosphere and surface. Using a physics-based calibration technique, we show that AirHARP can achieve high measurement accuracy in lab and field environments and exceed a benchmark accuracy requirement for modern aerosol and cloud climate observations. Our calibration technique makes the HARP design highly attractive for upcoming NASA climate missions.

The coupled variation of the three stable isotopes of oxygen in water is being studied as a relatively new tracer of the water cycle. Measurement by laser spectroscopy has a number of pitfalls that have hampered a wider exploration of this new tracer. We demonstrate successful analysis using Picarro's L2140-i analyzer and provide recommendations for other users. We find that removal of dissolved organic carbon is required when measurements are studied near the limits of instrumental accuracy.

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.

Dual thermistor radiosonde (DTR) comprising two (white and black) sensors with different emissivities was developed to correct the effects of solar radiation on temperature sensors based on in situ radiation measurements. All components contributing to the uncertainty of the radiation measurement and correction are analysed. The DTR methodology improves the accuracy of temperature measurement in the upper air within the framework of the traceability to the International System of Units.