Key drivers of large scale changes in North Atlantic atmospheric and oceanic circulations and their predictability

Authors:

Buwen Dong, Yevgeny Yevgeny Aksenov, Ioana Colfescu, Ben Harvey, Joël Hirschi, Simon Josey, Hua Lu, Jenny Mecking, Marilena Oltmanns, Scott Osprey, Jon Robson, Stefanie Rynders, Len Shaffrey, Bablu Sinha, Rowan Sutton, Antje Weisheimer

Major volcanic eruptions episodically disrupted the continuity of polar warming through aerosol forcing

npj Clean Air Springer Nature

Authors:

Roy Grainger, Basudev Swain, Scott Osprey, Rui Song, Marco Vountas

Abstract:

The polar regions are warming rapidly, exceeding the global average due to greenhouse gas emissionsfrom human activities. Using CMIP6 simulations, HadCRUT5 data, and MERRA-2 aerosol records, thisstudy shows that major 20th-century volcanic eruptions, Agung (1963), El Chicho´n (1982), and Pinatubo(1991) temporarily offset polar warming through sulfate-induced cooling. The Agung eruption suppressedArctic surface air temperature anomalies for approximately 4-5 years (1964–1968), El Chicho´n for asimilar duration (1983–1987), and Pinatubo for about 4-5 years (1992–1996), demonstrating a consistentmulti-year cooling response following each event.Without these eruptions, Arctic surface air temperatureanomalies would have increased by up to 0.5 °C, whereas volcanic activity caused short-term coolingranging from –0.07 °C to –0.4 °C. Arctic minimum temperatures (Tmin) are rising faster than maximumtemperatures (Tmax), indicating asymmetric warming. In contrast, Antarctic responses were weaker,moderated by oceanic and atmospheric dynamics. Collectively, these eruptions produced episodic multi-year cooling that temporarily interrupted the ongoing Arctic warming trajectory, with warming resumingas volcanic aerosol forcing diminished. Spatial patterns reveal pronounced warming in the central Arctic,Greenland, and Siberia in the absence of volcanic forcing, highlighting the role of eruptions in modulating polar warming and providing insights relevant to future geoengineering considerations.

Multi-decadal variability in skill of predicting ENSO spatial pattern

Geophysical Research Letters American Geophysical Union

Authors:

Matthew Wright, Antje WEISHEIMER, Tim WOOLLINGS

On the uses of a new linear scheme for stratospheric methane in global models: water source, transport tracer and radiative forcing

Authors:

BM Monge-Sanz, MP Chipperfield, A Untch, J-J Morcrette, A Rap, AJ Simmons

Overview of experiment design and comparison of models participating in phase 1 of the SPARC Quasi-Biennial Oscillation initiative (QBOi)

Geoscientific Model Development European Geosciences Union

Authors:

Neal Butchart, James A Anstey, Kevin Hamilton, Scott Osprey, Charles McLandress, Andrew C Bushell, Yoshio Kawatani, Young-Ha Kim, Francois Lott, John Scinocca, Tim Stockdale, Omar Bellprat, Peter Braesicke, Chiara Cagnazzo, Chih-Chieh Chen, Hye-Yeong Chun, Mikhail Dobrynin, Rolando R Garcia, Javier Garcia-Serrano, Lesley J Gray, Laura Holt, Tobias Kerzenmacher, Hiroaki Naoe, Holger Pohlmann, Jadwiga H Richter, Adam A Scaife, Verena Schenzinger, Federico Serva, Stefan Versick, Shingo Watanabe, Kohei Yoshida, Seiji Yukimoto