A selection of new science articles from the past week of interest to the SPARC community (a SPARC Office choice).

Trend analysis of the 20-year time series of stratospheric ozone profiles observed by the GROMOS microwave radiometer at Bern. By L. Moreira et al. in Atmospheric Chemistry and Physics.

Revisiting the evidence of increasing springtime ozone mixing ratios in the free troposphere over western North America. By M. Lin et al. in Geophysical Research Letters.

Blocking variability: Arctic Amplification versus Arctic Oscillation. By P. Hassanzadeh and Z. Kuang in Geophysical Research Letters.

Quantifying the uncertainty of the annular mode time scale and the role of the stratosphere. By J. Kim and T. Reichler in Climate Dynamics.

Abrupt reversal in emissions and atmospheric abundance of HCFC-133a (CF₃CH₂Cl). By M.K. Vollmer et al. in Geophysical Research Letters.

A minimum standard for publishing computational results in the weather and climate sciences. By D. Irving in the Bulletin of the American Meteorological Society.

Can cirrus cloud seeding be used for geoengineering? By J.E. Penner et al. in Geophysical Research Letters.