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

More-Persistent Weak Stratospheric Polar Vortex States Linked to Cold Extremes. By M. Kretschmer et al. in the Bulletin of the American Meteorological Society.

Modeling Seasonal Sudden Stratospheric Warming Climatology Based on Polar Vortex Statistics. By M.F. Horan and T. Reichler in the Journal of Climate.

Seasonal sensitivity of the Northern Hemisphere jet-streams to Arctic temperatures on subseasonal timescales. By E.A. Barnes and I.R. Simpson in the Journal of Climate.

Development of a Polar Stratospheric Cloud Model within the Community Earth System Model: Assessment of 2010 Antarctic Winter. By Y. Zhu et al. in the Journal of Geophysical Research: Atmospheres.

Brominated VSLS and their influence on ozone under a changing climate. By S. Falk et al. in Atmospheric Chemistry and Physics.

Ozone comparison between Pandora #34, Dobson #061, OMI, and OMPS in Boulder, Colorado, for the period December 2013–December 2016. By J. Herman et al. in Atmospheric Measurement Techniques.

An “island” in the stratosphere – on the enhanced annual variation of water vapour in the middle and upper stratosphere in the southern tropics and subtropics. By S. Lossow et al. in Atmospheric Chemistry and Physics.

Reanalysis comparisons of upper tropospheric–lower stratospheric jets and multiple tropopauses. By G.L. Manney et al. in Atmospheric Chemistry and Physics.

Snow-(N)AO teleconnection and its modulation by the Quasi-Biennal Oscillation. By Y. Peings et al. in the Journal of Climate.

Common Warming Pattern Emerges Irrespective of Forcing Location. By S.M. Kang et al. in the Journal of Advances in Modeling Earth Systems.

Potential impact of carbonaceous aerosol on the upper troposphere and lower stratosphere (UTLS) and precipitation during Asian summer monsoon in a global model simulation. By S. Fadnavis et al. in Atmospheric Chemistry and Physics.

Discussion papers – open for comment

Harmonisation and trends of 20-years tropical tropospheric ozone data. By E. Leventidou et al. in Atmospheric Chemistry and Physics Discussions.

Signatures by 3 October

There is a petition in circulation that is in the form of an open letter to Prime Minister Trudeau, regarding the non-renewal of the CCAR program in Canada.

Please follow the link below to review this petition:
https://docs.google.com/forms/<wbr></wbr>d/e/<wbr></wbr>1FAIpQLScX3iILUvOQc3MYnChYRYrv<wbr></wbr>UGDvJBAwHyDJi0W4LrHXr3CTTw/<wbr></wbr>viewform

The Intergovernmental Panel on Climate Change (IPCC), the UN body for assessing the science related to climate change, is calling for nominations of authors for the Sixth Assessment Report (AR6).
"We are seeking scientists with expertise across the disciplines assessed by the IPCC," said Hoesung Lee, Chair of the IPCC. "We also hope that more scientists from developing countries and more women scientists will be nominated as IPCC authors to give us diverse author teams that can provide a range of relevant perspectives."
The report outline consists of chapters with indicative bullets, listing topics to be considered in the assessment. Expertise is sought in the call for nominations to undertake the assessment of these topics.

View the detailed chapter outlines of the WGI report.

Find more information on how to apply.

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

Disentangling fast and slow responses of the East Asian summer monsoon to reflecting and absorbing aerosol forcings. By Z. Wang et al. in Atmospheric Chemistry and Physics.

Comparison of large-scale dynamical variability in the extratropical stratosphere among the JRA-55 family data sets: impacts of assimilation of observational data in JRA-55 reanalysis data. By M. Taguchi in Atmospheric Chemistry and Physics.

Shift of subtropical transport barriers explains observed hemispheric asymmetry of decadal trends of age of air. By G.P. Stiller in Atmospheric Chemistry and Physics.

An assessment of drift correction alternatives for CMIP5 decadal predictions. By D. Choudhury et al. in the Journal of Geophysical Research: Atmospheres.

Discussion papers – open for comment

Representation of solar tides in the stratosphere and lower mesosphere in state-of-the-art reanalyses and in satellite observations. By T. Sakazaki et al. in Atmospheric Chemistry and Physics Discussions.

Revising global ozone dry deposition estimates based on a new mechanistic parameterisation for air-sea exchange and the multi-year MACC composition reanalysis. By A.K. Luhar et al. in Atmospheric Chemistry and Physics Discussions.

Tropical convection regimes in climate models: evaluation with satellite observations. By A.K. Steiner et al. in Atmospheric Chemistry and Physics Discussions.

On 19-20 September 2017, a symposium took place in Paris, France, on the occasion of the 30th Anniversary of the Montreal Protocol: From the safeguard of the ozone layer to the protection of the Earth Climate. The event was organised by the International Ozone Commission and endorsed by SPARC.

Hailed as an example of exceptional international cooperation for the protection of the ozone layer, the Montreal Protocol became in 2010 the first international treaty to achieve universal ratification. In October 2016, the Kigali amendment was added to the Protocol for controlling the growth of the substitutes of ozone depleting substances, some of which are powerful greenhouse gases and thereby mitigating their impact on the Earth’s climate.

Find the programme and watch the videos of the symposium.

View the Montreal Protocol, its evolution and amendments.

Registration is now open for the 42nd COSPAR Scientific Assembly, taking place at the Pasadena Convention Center from 14-22 July 2018.

Early registration deadline: 27 April 2018
Abstract submission deadline: 9 February 2018

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

Detecting recovery of the stratospheric ozone layer. By M.P. Chipperfield et al. in Nature.

Comparison of four inverse modelling systems applied to the estimation of HFC-125, HFC-134a, and SF₆ emissions over Europe. By D. Brunner et al. in Atmospheric Chemistry and Physics.

The Impacts of Meteorology on the Seasonal and Interannual Variabilities of Ozone Transport from North America to East Asia. By Y. Zhu et al. in the Journal of Geophysical Research: Atmospheres.

Troposphere-stratosphere temperature trends derived from satellite data compared with ensemble simulations from WACCM. By W.J. Randel et al. in the Journal of Geophysical Research: Atmospheres.

Evaluating a space-based indicator of surface ozone-NOx-VOC sensitivity over mid-latitude source regions and application to decadal trends. By X. Jin et al. in the Journal of Geophysical Research: Atmospheres.

A quantitative analysis of the reactions involved in stratospheric ozone depletion in the polar vortex core. By I. Wohltmann et al. in Atmospheric Chemistry and Physics.

Particulate sulfur in the upper troposphere and lowermost stratosphere – sources and climate forcing. By B.G. Martinsson et al. in Atmospheric Chemistry and Physics.

Tropospheric ozone profiles by DIAL at Maïdo Observatory (Reunion Island): system description, instrumental performance and result comparison with ozone external data set. By Y. Duflot et al. in Atmospheric Measurement Techniques.

MJO-related tropical convection anomalies lead to more accurate stratospheric vortex variability in subseasonal forecast models. By C.I. Garfinkel and C. Schwartz in Geophysical Research Letters.

Regional temperature change potentials for short-lived climate forcers based on radiative forcing from multiple models. By B. Aamaas et al. in Atmospheric Chemistry and Physics.

Local and remote impacts of atmospheric cloud radiative effects onto the eddy-driven jet. By O. Watt-Meyer and D.M.W. Frierson in Geophysical Research Letters.

Uncovering the Edge of the Polar Vortex. By M. Serra et al. in the Journal of the Atmospheric Sciences.

Practical and intrinsic predictability of multi-scale weather and convectively-coupled equatorial waves during the active phase of an MJO. By Y. Ying and F. Zhang in the Journal of the Atmospheric Sciences.

An update on ozone profile trends for the period 2000 to 2016. By W. Steinbrecht et al. in Atmospheric Chemistry and Physics.

Review of Tropical-Extratropical Teleconnections on Intraseasonal Time Scales. By C. Stan in Reviews of Geophysics.

Driving Roles of Tropospheric and Stratospheric Thermal Anomalies in Intensification and Persistence of the Arctic Superstorm in 2012. By W. Tao et al. in Geophysical Research Letters.

A New Interpretation of Vortex-Split Sudden Stratospheric Warmings in Terms of Equilibrium Statistical Mechanics. By Y. Yasuda et al. in the Journal of the Atmospheric Sciences.

Discussion papers – open for comment

A global, space-based stratospheric aerosol climatology: 1979 to 2016. By L.W. Thomason et al. in Earth System Science Data Discussions.

Climatology and long-term evolution of ozone and carbon monoxide in the UTLS at northern mid-latitudes, as seen by IAGOS from 1995 to 2013. By Y. Cohen et al. in Atmospheric Chemistry and Physics Discussions.

Revisiting internal gravity waves analysis using GPS RO density profiles: comparison with temperature profiles and application for wave field stability study. By P. Pisoft et al. in Atmospheric Measurement Techniques Discussions.

Evaluation of stratospheric age-of-air from CF₄, C₂F₆, C₃F₈, CHF₃, HFC-125, HFC-227ea and SF₆; implications for the calculations of halocarbon lifetimes, fractional release factors and ozone depletion potentials. By E. Leedham Elvidge et al. in Atmospheric Chemistry and Physics Discussions.

Simultaneous assimilation of ozone profiles from multiple UV-VIS satellite instruments. By J. van Peet et al. in Atmospheric Chemistry and Physics Discussions.

Total ozone trends from 1979 to 2016 derived from five merged observational datasets – the emergence into ozone recovery. By M. Weber et al. in Atmospheric Chemistry and Physics Discussions.

Comments welcome until 25 September

A panel of experts has created an updated draft position of the American Geophysical Union (AGU) on geoengineering. AGU first formulated an official position on geoengineering in 2009, when it adopted a statement in collaboration with the American Meteorological Society. AGU last updated its geoengineering statement in 2012. The organization encourages its members to provide written feedback about this draft statement during a 30-day comment period that opens today and closes on Monday, 25 September at 11:59 p.m. Eastern time. Find more information on their website: https://eos.org/agu-news/position-statement-on-geoengineering-call-for-comments.

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

Stratospheric ozone intrusion events and their impacts on tropospheric ozone in the Southern Hemisphere. By J.W. Greenside et al. in Atmospheric Chemistry and Physics.

The version 3 OMI NO₂ standard product. By N.A. Krotkov et al. in Atmospheric Measurement Techniques.

Lightning NOx Emissions: Reconciling measured and modeled estimates with updated NOx chemistry. By B.A. Nault et al. in Geophysical Research Letters.

Stratospheric intrusion-influenced ozone air quality exceedences investigated in the NASA MERRA-2 Reanalysis. By K.E. Knowland et al. in Geophysical Research Letters.

Does the lower stratosphere provide predictability for month-ahead wind electricity generation in Europe? By R. Beerli et al. in the Quarterly Journal of the Royal Meteorological Society.

Discussion papers – open for comment

Characterizing Sampling and Quality Screening Biases in Infrared and Microwave Limb Sounding. By L.F. Millan et al. in Atmospheric Chemistry and Physics Discussions.

View SPARC eNews September 2017.