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An examination is made of stratospheric climate, circulation, and variability in configurations of the Hadley Centre Global Environmental Model version 2 (HadGEM2) differing only in stratospheric resolution and the placement of the model lid. This is made in the context of historical reconstructions of twentieth-century climate. A reduction in the westerly bias in the Northern Hemisphere polar night jet is found in the high-top model. The authors also find significant differences in the expression of tropical stratospheric variability, finding improvements in the high-top model for the presence of the quasi-biennial oscillation, for tropical upwelling consistent with interim European Centre for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-Interim) data, and for interannual changes in stratospheric water vapor concentration comparable to satellite observations. Further differences are seen at high latitudes during winter in the frequency of occurrence of sudden stratospheric warmings (SSWs). The occurrence rate of SSWs in the high-top simulations, (7.2 ± 0.5) decade−1, is statistically consistent with observations, (6.0 ± 1.0) decade−1, whereas they are one-third as frequent in the low-top simulations, (2.5 ± 0.5) decade−1. Furthermore, the structure of the timing of winter final warmings is only captured in the high-top model. A similar characterization for the time evolution of the width of the tropical upper troposphere is found between model configurations. It is concluded that an adequate representation of the stratosphere is required to capture the important modes of tropical and extratropical stratospheric variability in models. [ABSTRACT FROM AUTHOR]

The article presents a study which uses laser spectroscopy to measure variations of isotopes in atmospheric water vapour. The study compares two laser spectroscopic systems which are based on cavity ring-down spectroscopy and off-axis integrated cavity output spectroscopy. It looks into uncertain components of continuous measurements including effects of water vapour mixing ratio and measurement stability.

The article presents a study which describes the application of SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) lunar occultation water vapor measurements. The study illustrates the retrieval approach for radiative transfer model on the SCIAMACHY measurements. It also presents retrieval optimizations and sensitivity studies.

The article presents a study on the accuracy of atmospheric columnar integrated water vapor measurements based on the Mitigation of Electromagnetic Transmission errors induced by Atmospheric Water Vapour Effects (METAWAVE) project. The study investigates the mitigation of integrated water vapor (IWV) effects into the Spaceborne Interferometric Synthetic Aperture Radar (InSAR). It concludes that InSAR sensitivity to water vapor turbulent component is higher compared to other instruments.

The article presents a study which explores the concept of flux correction for closed-path laser spectrometers. The study uses a Fast Greenhouse Gas Analyzer in an effort to look into water's (H2O) phase shift and damping with respect of methane (CH4) signal. It discovers that the measurement of trace gas flux is directly affected by the damping of the water vapor signal and cross-sensitivity effects to water.

The article presents a study which explores the water vapour concentration distribution through the SondRad instrument in the Particles, Hydrogen and Oxygen Chemistry (PHOCUS) payload. The study describes the impact of simulations through finite element method (FEM) modelling on the performance of the instrument. It also looks into the 183 giga hertz (GHz) radiofrequency (RF) and 557 GHz channel calibration system and 57 GHz intermediate frequency (IF) channel calibration system.