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

Climate change: Does international research fulfill global demands and necessities? By D. Klingelhöfer et al. in Environmental Sciences Europe.

21st century trends in mixing barriers and eddy transport in the lower stratosphere. By M. Abalos and A. De la Camara in the Geophysical Research Letters.

Impact of the eruption of Mt Pinatubo on the chemical composition of the stratosphere. By M. Kilian, S. Brinkop, and P. Jöckel in Atmospheric Chemistry and Physics.

Seasonal Forecasts of the Exceptional Northern Hemisphere Winter of 2020. By S.H. Lee et al. in the Geophysical Research Letters.

Responses of the East Asian summer monsoon to aerosol forcing in CMIP5 models: The role of upper‐tropospheric temperature change. By J. Mu and Z. Wang in the International Journal of Climatology.

Arctic Ozone Loss in March 2020 and Its Seasonal Prediction in CFSv2: A Comparative Study with the 1997 and 2011 Cases. By J. Rao and C.I. Garfinkel in the Journal of Geophysical Research: Atmospheres.

Reconciling the climate and ozone response to the 1257 CE Mount Samalas eruption. By D.C. Wade et al. in the Proceedings of the National Academy of Sciences of the United States of America.

Dependence of atmospheric transport into the Arctic on the meridional extent of the Hadley cell. By H. Yang et al. in the Geophysical Research Letters.

Discussion papers – open for comment

On a new assessment method for long-term chemistry-climate simulations in the UTLS based on IAGOS data: application to MOCAGE CCMI-REFC1SD simulation. By Y. Cohen et al. in Geoscientific Model Development

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

Climate change and trend analysis of temperature: the case of Addis Ababa, Ethiopia. By Z.A. Alemu and M.O. Dioha in Environmental Systems Research.

Characteristics of Tropopause Polar Vortices Based on Observations over the Greenland Ice Sheet. By S.M. Borg, S.M. Cavallo and D.D. Turner in the Journal of Applied Meteorology and Climatology.

Superposition of gravity waves with different propagation characteristics observed by airborne and space-borne infrared sounders. By I. Krisch et al. in Atmospheric Chemistry and Physics.

Architecting the Future of Weather Satellites. By M.W. Maier et al. in the Bulletin of the American Meteorological Society.

Projected strengthening of the extratropical surface impacts of the stratospheric Quasi‐Biennial Oscillation. By J. Rao, C.I. Garfinkel, and I.P. White in the Geophysical Research Letters.

Prepare Scientists to Engage in Science‐Policy. By E. von Schneidemesser, M. Melamed, and J. Schmale in Earth’s Future.

Discussion papers – open for comment:

Effects of prescribed CMIP6 ozone on simulating the Southern Hemisphere atmospheric circulation response to ozone depletion. By I. Ivanciu et al. in Atmospheric Chemistry and Physics.

Modeling study of the impact of SO2 volcanic passive emissions on the tropospheric sulfur budget. By C. Lamotte et al. in Atmospheric Chemistry and Physics.

Using a global network of temperature lidars to identify temperature biases in the upper stratosphere in ECMWF reanalyses. By G. Marlton et al. in Atmospheric Chemistry and Physics.

Understanding the development of systematic errors in the Asian Summer Monsoon. By G.M. Martin et al. in Geoscientific Model Development.

Quasi-coincident Observations of Polar Stratospheric Clouds by Ground-based Lidar and CALIOP at Concordia (Dome C, Antarctica) from 2014 to 2018. By M. Snels et al. in Atmospheric Chemistry and Physics.

Measurement Report: Lidar measurements of stratospheric aerosol following the Raikoke and Ulawun volcanic eruptions. By G. Vaughan, D. Wareing, and H. Ricketts in Atmospheric Chemistry and Physics.

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

Modeling evidence of QBO‐MJO connection: A case study. By S.-Y. Back, J.-Y. Han, and S.-W. Son in the Geophysical Research Letters.

On the intermittency of orographic gravity wave hotspots and its importance for middle atmosphere dynamics. By A. Kuchar et al. In Weather and Climate Dynamics.

Confinement of air in the Asian monsoon anticyclone and pathways of convective air to the stratosphere during the summer season. By B. Legras and S. Bucci in Atmospheric Chemistry and Physics.

Reappraisal of the climate impacts of ozone‐depleting substances. By O. Morgenstern et al. in the Geophysical Research Letters.

Broadening Impact of Field Campaigns: Integrating Meteorological and Chemical Observations. By G.L. Mullendore et al. in the Bulletin of the American Meteorological Society.

On the linkage between Rossby wave phase speed, atmospheric blocking and Arctic Amplification. By J. Riboldi et al. in the Geophysical Research Letters.

Tropospheric forcing of the 2019 Antarctic sudden stratospheric warming. By X. Shen, L. Wang, and S. osprey in the Geophysical Research Letters.

Prediction of the quasi‐biennial oscillation with a multi‐model ensemble of QBO‐resolving models. By T.N. Stockdale et al. in the Quarterly Journal of the Royal Meteorological Society.

Near complete local reduction of Arctic stratospheric ozone by severe chemical loss in spring 2020. By I. Wohltmann et al. in the Geophysical Research Letters.

Climate research Foote note. By B. Wake in nature: climate change.

Discussion papers – open for comment:

Global Carbon Budget 2020. By P. Friedlingstein et al. In Earth System Science Data.

Location controls the findings of ground-based PSC observations. By M. Tesche, P. Achtert, and M.C. Pitts in Atmospheric Chemistry and Physics.

The Impact of Increasing Stratospheric Radiative Damping on the QBO Period. By T. Zhou et al. in Atmospheric Chemistry and Physics.

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

Application of Deep Learning to Estimate Atmospheric Gravity Wave Parameters in Reanalysis Datasets. By D. Matsuoka et al. in the Geophysical Research Letters.

COnstraining ORographic Drag Effects (COORDE): a model comparison of resolved and parametrized orographic drag. By A. van Niekerk et al. in the Journal of Advances in Modeling Earth Systems.

Wintertime Southern Hemisphere jet streams shaped by interaction of transient eddies with Antarctic orography. By M. Patterson et al. in the Journal of the Climate.

Multi‐Decadal Measurements of UTLS Gravity Waves Derived from Commercial Flight Data. By C.J. Wright and T.P. Banyard in the Journal of Geophysical Research: Atmospheres.

Variations in the Frequency of Stratospheric Sudden Warmings in CMIP5 and CMIP6 and Possible Causes. By Z. Wu and T. Reichler in the Journal of the Climate.

Discussion papers – open for comment:

The Spring Transition of the North Pacific Jet and its Relation to Deep Stratosphere-to-Troposphere Mass Transport over Western North America. By M.L. Breeden et al. in Atmospheric Chemistry and Physics.

Sensitivity of stratospheric water vapour to variability in tropical tropopause temperatures and large-scale transport. By J.W. Smith et al. in Atmospheric Chemistry and Physics.

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

Reponses of middle atmospheric circulation to the 2009 major sudden stratospheric warming. By SY. Gu et al. in Earth and Planetary Physics.

The Impact on the Ozone Layer of a Potential Fleet of Civil Hypersonic Aircraft. By D. Kinnison et al. in Earth’s Future.

Small-scale variability of stratospheric ozone during the sudden stratospheric warming 2018/2019 observed at Ny-Ålesund, Svalbard. By F. Schranz et al. in Atmospheric Chemistry and Physics.

A baseline for global weather and climate simulations at 1 km resolution. By N.P. Wedi et al. in the Journal of Advances in Modeling Earth Systems.

Robust acceleration of stratospheric moistening and its radiative feedback under greenhouse warming. By Y. Xia, Y. Huang, and Y. Hu in the Journal of Geophysical Research: Atmospheres.

Discussion Papers – open for comment:

Model physics and chemistry causing intermodel disagreement within the VolMIP-Tambora Interactive Stratospheric Aerosol ensemble. By M. Clyne et al. in Atmospheric Chemistry and Physics.

The call for nominations to SPARC’s Scientific Steering Group (SSG) is now open. The SSG currently comprises 12-14 researchers from around the world with a wide range of expertise in atmospheric dynamics and chemistry. They guide SPARC’s priorities and activities, working together with the SSG co-chairs and the SPARC project office. SSG members will be responsible for the new SPARC implementation plan, the regional and international research agendas, and ensuring that SPARC’s priorities align with those of the new WCRP strategy.

Please find the Terms of Reference as a guideline to the work of the SSG.

The deadline for nominations is 30 October 2020. Nominations can be submitted through the below online form (including the upload of a publications list). Please note that you can either nominate a candidate or nominate yourself. The SSG takes a strategic view of SPARC’s role, so we are looking for individuals with a broad view of atmospheric science and climate change as well as expertise in their own field. Scientific expertise, career stage as well as gender and geographical balance are taken into account. The initial term of service is for four years (January 2022 – December 2025), with a possible extension of two years.

We recommend that early career researchers consider getting involved in specific activities first, including leadership roles, as involvement in international activities is a great way to broaden one’s horizons. Activity Leaders can attend the annual SSG meetings. We are happy to advise anyone unsure about how best to get involved. If you are interested in getting involved in SPARC in other ways, including ideas for new foci, please visit the SPARC webpage for more information: www.sparc-climate.org/get-involved or contact the SPARC Office.

On September 16th, the International Day for the Preservation of the Ozone Layer, the International Ozone Commission has released the following satement:

The International Ozone Commission, on the 33th anniversary of the Montreal Protocol, reports successes and remaining challenges for understanding ozone layer recovery

September 16th is the International Day for the Preservation of the Ozone Layer, celebrating the 1987 anniversary of the Montreal Protocol on Substances that Deplete the Ozone Layer. The Montreal Protocol is the globally ratified treaty that controls the production and consumption of ozone depleting substances (ODSs) and many replacements for these substances.

The theme of the International Day for the Preservation of the Ozone Layer on 16 September 2020 is: “Ozone for life: 35 years of ozone layer protection”. This 35-year period marks the adoption of the Vienna Convention for the Protection of the Ozone Layer. The Convention mandates a worldwide ozone research effort to understand and measure the Earth’s critically important ozone layer. Significant anomalous Antarctic and Arctic ozone events in the 2019-2020 period demonstrated the necessity of these ongoing measurements and associated research.

The Antarctic ozone hole in September-October 2019 was relatively small compared to the very large and deep ozone holes observed in the 1990-2010 period. The ozone hole occurs every year since the early 1980s and is caused by high levels of human-produced Ozone Depleting Substances (ODS) in our atmosphere. ODS concentrations are still high enough to cause severe spring-time ozone destruction, and the gradual decline of ODSs is contributing to an improvement of Antarctic ozone levels. However, the main cause of the weak 2019 hole was the very active meteorological conditions in the AugustSeptember 2019 period compared to prior years. This active stratospheric meteorology drove an early shut-down of the ozone depleting conditions. The origin of this abnormal meteorology is an ongoing research topic.

In sharp contrast, Arctic ozone depletion, which is generally much weaker than its Antarctic counterpart, was particularly severe in the spring of 2020. This depletion was caused by a combination of factors that primarily arose due to unusually weak stratospheric meteorological weather events in the December through March period compared to all prior years. Typically, these events drive movements of ozone-rich air through the polar vortex. The lack of weather events led to an unusually strong and cold Arctic polar vortex during the 2019-2020 winter, and a lack of ozone transport. The combination of prolonged cold temperatures (enabling strong ozone depleting reactions) and lack of ozone transport
caused this rare large Arctic ozone depletion.

Total atmospheric ODS levels continue to decrease around the world according to the findings of the Scientific Assessment of Ozone Depletion: 2018 [WMO/UNEP, 2018] although the decrease of CFC-11 levels, one of the main ODS, has slowed in recent years. The 20-year atmospheric ODS decline contributes to the improvements observed for the ozone hole. Without measurements and scientific analysis, the slowing in the decrease of CFC-11 would not have been detected.

Our ability to follow significant ozone events is crucially dependent on satellite, balloon, and groundbased ozone observing systems. Maintenance and continuation of ozone and ancillary observations is vital for improving our understanding of interactions between climate change and ozone depletion, for ozone layer recovery studies, and for research into potential future impacts on the ozone layer. The events of 2019-2020, coupled with the celebration of the Vienna Convention’s 35th Anniversary help us recall the Convention’s Article 3: “The Parties undertake to promote or establish, … , joint or complementary programmes for systematic observation of the state of the ozone layer and other relevant parameters.” The Vienna Convention’s foresight allows scientists to closely follow and understand our changing ozone layer.

Due to the current COVID-19 pandemic, the 2020 Quadrennial Ozone Symposium, which was to be held in Seoul, South Korea on 5-9 October 2020, has been postponed to 2021 during the same period.

Find the complete statement

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

Global-scale distribution of ozone in the remote troposphere from the ATom and HIPPO airborne field missions. By I. Bourgeois et al. in Atmospheric Chemistry and Physics.

Downward migration of the zonal‐mean circulation in the tropical atmosphere. By K. DallaSanta and E.P. Gerber in the Geophysical Research Letters.

Effect of deep convection on the tropical tropopause layer composition over the southwest Indian Ocean during austral summer. By S. Evan et al. in Atmospheric Chemistry and Physics.

Predictability of European Winters 2017/2018 and 2018/2019: Contrasting influences from the Tropics and stratosphere. By J. Knight et al. in the Atmospheric Science Letters.

Earth System Model Evaluation Tool (ESMValTool) v2.0 – diagnostics for emergent constraints and future projections from Earth system models in CMIP. By A. Lauer et al. in Geoscientific Model Development.

Stratospheric carbon isotope fractionation and tropospheric histories of CFC-11, CFC-12 and CFC-113 isotopologues. By M. Thomas et al. in Atmospheric Chemistry and Physics.

The effect of interactive ozone chemistry on weak and strong stratospheric polar vortex events. By J. Oehrlein, G. Chiodo, and L.N. Polvani in Atmospheric Chemistry and Physics.

Discussion papers – open for comment:

A Global Total Column Ozone Climate Data Record. By G.E. Bodeker et al. in Earth System Science Data.

Influence of ENSO on entry stratospheric water vapor in coupled chemistry-ocean CCMI and CMIP6 models. By C.I. Garfinkel et al. in Atmospheric Chemistry and Physics.

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

Seasonal Variation of the Quasi‐Biennial Oscillation Descent. By L. Coy et al. in the Journal of Geophysical Research: Atmospheres.

CMIP6 climate models imply high committed warming. By C. Huntingford, M.S. Williamson, and F.J.M.M. Nijsse in Climatic Change.

Lidar observations of large‑amplitude mountain waves in the stratosphere above Tierra del Fuego, Argentina. By N. Kaifler et al. in Scientific Reports.

Far‐ranging impact of mountain waves excited over Greenland on stratospheric dehydration and rehydration. By R. Kivi et al. in the Journal of Geophysical Research: Atmospheres.

Sensitivity of trends to estimation methods and quantification of subsampling effects in global radiosounding temperature and humidity time series. By SY Souleyname et al. in the International Journal of Climatology.

The anomalous 2019 Antarctic ozone hole in the GEOS Constituent Data Assimilation System with MLS observations. By K. Wargan et al. in the Journal of Geophysical Research: Atmospheres.

Seasonal Forecasts of the Twentieth Century. By A. Weisheimer et al. in the Bulletin of the American Meteorological Society.

Discussion papers – open for comment:

Upward transport into and within the Asian monsoon anticyclone as inferred from StratoClim trace gas observations. By M. von Hobe et al. in Atmospheric Chemistry and Physics.

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

Projecting ozone hole recovery using an ensemble of chemistry–climate models weighted by model performance and independence. By M. Amos et al. in Atmospheric Chemistry and Physics.

Historical total ozone radiative forcing derived from CMIP6 simulations. By R. Bieltvedt Skeie et al. in npj Climate and Atmospheric Science.

Airborne measurements and large-eddy simulations of small-scale gravity waves at the tropopause inversion layer over Scandinavia. By S. Gisinger, J. Wagner, and B. Witschas in Atmospheric Chemistry and Physics.

How can we improve the driving of the Quasi‐Biennial Oscillation in climate models? By A. Hertzog in the Journal of Geophysical Research: Atmospheres.

Decline in Temperature Variability on Svalbard. By  S. Hølleland and H.A. Karlsen in the Journal of the Climate.

Tropical cyclones impact on tropopause and the lower stratosphere vapour based on satellite data. By B. Jiang et al., in the Atmospheric Science Letters.

First Direct Observational Evidence for Secondary Gravity Waves Generated by Mountain Waves over the Andes. By M. Kogure et al. in the Geophysical Research Letters.

Seasonal and Latitudinal Variability of the Gravity Wave Spectrum in the Lower Stratosphere. By E.A. Lindgren et al. in the Journal of Geophysical Research: Atmospheres.

The Interaction between Moist Convection and the Atmospheric Circulation in the Tropics. By L. Tomassini in the Bulletin of the American Meteorological Society.

Discussion papers – open for comment:

Technical Note: First comparison of wind observations from ESA’s satellite mission Aeolus and ground-based Radar wind profiler network of China. By J. Guo et al. in Atmospheric Chemistry and Physics.

Radiosounding HARMonization (RHARM): a new homogenized dataset of radiosounding temperature, humidity and wind profiles with uncertainty. By F. Madonna et al. in Earth System Science Data.