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Marlene Kretschmer
,
Dim Coumou
,
Laurie Agel
,
Mathew Barlow
,
Eli Tziperman
, and
Judah Cohen

Abstract

The extratropical stratosphere in boreal winter is characterized by a strong circumpolar westerly jet, confining the coldest temperatures at high latitudes. The jet, referred to as the stratospheric polar vortex, is predominantly zonal and centered around the pole; however, it does exhibit large variability in wind speed and location. Previous studies showed that a weak stratospheric polar vortex can lead to cold-air outbreaks in the midlatitudes, but the exact relationships and mechanisms are unclear. Particularly, it is unclear whether stratospheric variability has contributed to the observed anomalous cooling trends in midlatitude Eurasia. Using hierarchical clustering, we show that over the last 37 years, the frequency of weak vortex states in mid- to late winter (January and February) has increased, which was accompanied by subsequent cold extremes in midlatitude Eurasia. For this region, 60% of the observed cooling in the era of Arctic amplification, that is, since 1990, can be explained by the increased frequency of weak stratospheric polar vortex states, a number that increases to almost 80% when El Niño–Southern Oscillation (ENSO) variability is included as well.

Full access
Judah Cohen
,
Jason C. Furtado
,
Justin Jones
,
Mathew Barlow
,
David Whittleston
, and
Dara Entekhabi

Abstract

Previous research has linked wintertime Arctic Oscillation (AO) variability to indices of Siberian snow cover and upward wave activity flux in the preceding fall season. Here, daily data are used to examine the surface and tropospheric processes that occur as the link between snow cover and upward forcing into the stratosphere develops. October Eurasian mean snow cover is found to be significantly related to sea level pressure (SLP) and to lower-stratosphere (100 hPa) meridional heat flux. Analysis of daily SLP and 100-hPa heat flux shows that in years with high October snow, the SLP is significantly higher from approximately 1 November to 15 December, and the 100-hPa heat flux is significantly increased with a two-week lag, from approximately 15 November to 31 December. During November–December, there are periods with upward wave activity flux extending coherently from the surface to the stratosphere, and these events occur nearly twice as often in high snow years compared to low snow years. The vertical structure of these events is a westward-tilting pattern of high eddy heights, with the largest normalized anomalies near the surface in the same region as the snow and SLP changes. These results suggest that high SLP develops in response to the snow cover and this higher pressure, in turn, provides part of the structure of a surface-to-stratosphere wave activity flux event, thus making full events more likely. Implications for improved winter forecasts exist through recognition of these precursor signals.

Full access
Christopher G. Fletcher
,
Steven C. Hardiman
,
Paul J. Kushner
, and
Judah Cohen

Abstract

Variability in the extent of fall season snow cover over the Eurasian sector has been linked in observations to a teleconnection with the winter northern annular mode pattern. Here, the dynamics of this teleconnection are investigated using a 100-member ensemble of transient integrations of the GFDL atmospheric general circulation model (AM2). The model is perturbed with a simple persisted snow anomaly over Siberia and is integrated from October through December. Strong surface cooling occurs above the anomalous Siberian snow cover, which produces a tropospheric form stress anomaly associated with the vertical propagation of wave activity. This wave activity response drives wave–mean flow interaction in the lower stratosphere and subsequent downward propagation of a negative-phase northern annular mode response back into the troposphere. A wintertime coupled stratosphere–troposphere response to fall season snow forcing is also found to occur even when the snow forcing itself does not persist into winter. Finally, the response to snow forcing is compared in versions of the same model with and without a well-resolved stratosphere. The version with the well-resolved stratosphere exhibits a faster and weaker response to snow forcing, and this difference is tied to the unrealistic representation of the unforced lower-stratospheric circulation in that model.

Full access
Ziyi Cai
,
Qinglong You
,
Fangying Wu
,
Hans W. Chen
,
Deliang Chen
, and
Judah Cohen

Abstract

The Arctic has experienced a warming rate higher than the global mean in the past decades, but previous studies show that there are large uncertainties associated with future Arctic temperature projections. In this study, near-surface mean temperatures in the Arctic are analyzed from 22 models participating in phase 6 of the Coupled Model Intercomparison Project (CMIP6). Compared with the ERA5 reanalysis, most CMIP6 models underestimate the observed mean temperature in the Arctic during 1979–2014. The largest cold biases are found over the Greenland Sea the Barents Sea, and the Kara Sea. Under the SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios, the multimodel ensemble mean of 22 CMIP6 models exhibits significant Arctic warming in the future and the warming rate is more than twice that of the global/Northern Hemisphere mean. Model spread is the largest contributor to the overall uncertainty in projections, which accounts for 55.4% of the total uncertainty at the start of projections in 2015 and remains at 32.9% at the end of projections in 2095. Internal variability uncertainty accounts for 39.3% of the total uncertainty at the start of projections but decreases to 6.5% at the end of the twenty-first century, while scenario uncertainty rapidly increases from 5.3% to 60.7% over the period from 2015 to 2095. It is found that the largest model uncertainties are consistent cold bias in the oceanic regions in the models, which is connected with excessive sea ice area caused by the weak Atlantic poleward heat transport. These results suggest that large intermodel spread and uncertainties exist in the CMIP6 models’ simulation and projection of the Arctic near-surface temperature and that there are different responses over the ocean and land in the Arctic to greenhouse gas forcing. Future research needs to pay more attention to the different characteristics and mechanisms of Arctic Ocean and land warming to reduce the spread.

Full access
James Foster
,
Glen Liston
,
Randy Koster
,
Richard Essery
,
Helga Behr
,
Lydia Dumenil
,
Diana Verseghy
,
Starly Thompson
,
David Pollard
, and
Judah Cohen

Abstract

Confirmation of the ability of general circulation models (GCMs) to accurately represent snow cover and snow mass distributions is vital for climate studies. There must be a high degree of confidence that what is being predicted by the models is reliable, since realistic results cannot be assured unless they are tested against results from observed data or other available datasets. In this study, snow output from seven GCMs and passive-microwave snow data derived from the Nimbus-7 Scanning Multichannel Microwave Radiometer (SMMR) are intercompared. National Oceanic and Atmospheric Administration satellite data are used as the standard of reference for snow extent observations and the U.S. Air Force snow depth climatology is used as the standard for snow mass. The reliability of the SMMR snow data needs to be verified, as well, because currently this is the only available dataset that allows for yearly and monthly variations in snow depth. [The GCMs employed in this investigation are the United Kingdom Meteorological Office, Hadley Centre GCM, the Max Planck Institute for Meteorology/University of Hamburg (ECHAM) GCM, the Canadian Climate Centre GCM, the National Center for Atmospheric Research (GENESIS) GCM, the Goddard Institute for Space Studies GCM, the Goddard Laboratory for Atmospheres GCM and the Goddard Coupled Climate Dynamics Group (AIRES) GCM.] Data for both North America and Eurasia are examined in an effort to assess the magnitude of spatial and temporal variations that exist between the standards of reference, the models, and the passive microwave data. Results indicate that both the models and SMMR represent seasonal and year-to-year snow distributions fairly well. The passive microwave data and several of the models, however, consistently underestimate snow mass, but other models overestimate the mass of snow on the ground. The models do a better job simulating winter and summer snow conditions than in the transition months. In general, the underestimation by SMMR is caused by absorption of microwave energy by vegetation. For the GCMs, differences between observed snow conditions can be ascribed to inaccuracies in simulating surface air temperatures and precipitation fields, especially during the spring and fall.

Full access
Hengchun Ye
,
Eric J. Fetzer
,
Ali Behrangi
,
Sun Wong
,
Bjorn H. Lambrigtsen
,
Crysti Y. Wang
,
Judah Cohen
, and
Brandi L. Gamelin

Abstract

This study uses 45 years of observational records from 517 historical surface weather stations over northern Eurasia to examine changing precipitation characteristics associated with increasing air temperatures. Results suggest that warming air temperatures over northern Eurasia have been accompanied by higher precipitation intensity but lower frequency and little change in annual precipitation total. An increase in daily precipitation intensity of around 1%–3% per each degree of air temperature increase is found for all seasons as long as a station’s seasonal mean air temperature is below about 15°–16°C. This threshold temperature may be location dependent. At temperatures above this threshold, precipitation intensity switches to decreasing with increasing air temperature, possibly related to decreasing water vapor associated with extreme high temperatures. Furthermore, the major atmospheric circulation of the Arctic Oscillation, Scandinavian pattern, east Atlantic–western Eurasian pattern, and polar–Eurasian pattern also have significant influences on precipitation intensity in winter, spring, and summer over certain areas of northern Eurasia.

Full access
T. A. Moon
,
R. Thoman
,
M. L. Druckenmiller
,
Brandon Ahmasuk
,
Stacia A. Backensto
,
Thomas J. Ballinger
,
Rasmus Benestad
,
Logan. T. Berner
,
Germar H. Bernhard
,
Uma S. Bhatt
,
Siiri Bigalke
,
W. BjerkeJarle
,
Brian Brettschneider
,
Hanne H. Christiansen
,
Judah L. Cohen
,
Bertrand Decharme
,
Chris Derksen
,
Dmitry Divine
,
Jensen Drost
,
Matthew L. Druckenmiller
,
Alesksandra EliasChereque
,
Howard E. Epstein
,
Robert S. Fausto
,
Xavier Fettweis
,
Vitali E. Fioletov
,
Bruce C. Forbes
,
Gerald V. Frost
,
Sebastian Gerland
,
Scott J. Goetz
,
Jens-Uwe Grooß
,
Edward Hanna
,
Inger Hanssen-Bauer
,
Stefan Hendricks
,
Robert M. Holmes
,
Iolanda Ialongo
,
Ketil Isaksen
,
Bjørn Johnsen
,
Timothy Jones
,
Robb S.A. Kaler
,
Lars Kaleschke
,
Seong-Joong Kim
,
Zachary M. Labe
,
Rick Lader
,
Kaisa Lakkala
,
Mark J. Lara
,
Jackie Lindsey
,
Bryant D. Loomis
,
Kari Luojus
,
Matthew J. Macander
,
Jostein Mamen
,
Ken D. Mankoff
,
Gloria L. Manney
,
Stephanie A. McAfee
,
James W. McClelland
,
Walter N. Meier
,
Twila A. Moon
,
G. W. K. Moore
,
Thomas L. Mote
,
Lawrence Mudryk
,
Rolf Müller
,
Kelsey E. Nyland
,
James E. Overland
,
Julia K. Parrish
,
Donald K. Perovich
,
Guðrún Nína Petersen
,
Alek Petty
,
Gareth K. Phoenix
,
Kristin Poinar
,
Mika Rantanen
,
Robert Ricker
,
Vladimir E. Romanovsky
,
Shawn P. Serbin
,
Mark C. Serreze
,
Gay Sheffield
,
Alexander I. Shiklomanov
,
Nikolay I. Shiklomanov
,
Sharon L. Smith
,
Robert G. M. Spencer
,
Dmitry A. Streletskiy
,
Anya Suslova
,
Tove Svendby
,
Suzanne E. Tank
,
Marco Tedesco
,
Richard L. Thoman
,
Xiangshan Tian-Kunze
,
Mary-Louise Timmermans
,
Hans Tømmervik
,
Mikhail Tretiakov
,
Donald A. Walker
,
John E. Walsh
,
Muyin Wang
,
Melinda Webster
,
Adrian Wehrlé
,
Dedi Yang
,
Scott Zolkos
,
Jessicca Allen
,
Amy V. Camper
,
Bridgette O. Haley
,
Gregory Hammer
,
S. Love-Brotak
,
Laura Ohlmann
,
Lukas Noguchi
,
Deborah B. Riddle
, and
Sara W. Veasey
Open access
Tim Boyer
,
Ellen Bartow-Gillies
,
A. Abida
,
Melanie Ades
,
Robert Adler
,
Susheel Adusumilli
,
W. Agyakwah
,
Brandon Ahmasuk
,
Laura S. Aldeco
,
Mihai Alexe
,
Eric J. Alfaro
,
Richard P. Allan
,
Adam Allgood
,
Lincoln. M. Alves
,
Jorge A. Amador
,
John Anderson
,
B. Andrade
,
Orlane Anneville
,
Yasuyuki Aono
,
Anthony Arguez
,
Carlo Arosio
,
C. Atkinson
,
John A. Augustine
,
Grinia Avalos
,
Cesar Azorin-Molina
,
Stacia A. Backensto
,
Stephan Bader
,
Julian Baez
,
Rebecca Baiman
,
Thomas J. Ballinger
,
Alison F. Banwell
,
M. Yu Bardin
,
Jonathan Barichivich
,
John E. Barnes
,
Sandra Barreira
,
Rebecca L. Beadling
,
Hylke E. Beck
,
Emily J. Becker
,
E. Bekele
,
Guillem Martín Bellido
,
Nicolas Bellouin
,
Angela Benedetti
,
Rasmus Benestad
,
Christine Berne
,
Logan. T. Berner
,
Germar H. Bernhard
,
Uma S. Bhatt
,
A. E. Bhuiyan
,
Siiri Bigalke
,
Tiago Biló
,
Peter Bissolli
,
W. Bjerke Jarle
,
Kevin Blagrave
,
Eric S. Blake
,
Stephen Blenkinsop
,
Jessica Blunden
,
Oliver Bochníček
,
Olivier Bock
,
Xavier Bodin
,
Michael Bosilovich
,
Olivier Boucher
,
Deniz Bozkurt
,
Brian Brettschneider
,
Francis G. Bringas
,
Francis Bringas
,
Dennis Buechler
,
Stefan A. Buehler
,
Brandon Bukunt
,
Blanca Calderón
,
Suzana J. Camargo
,
Jayaka Campbell
,
Diego Campos
,
Laura Carrea
,
Brendan R. Carter
,
Ivona Cetinić
,
Don P. Chambers
,
Duo Chan
,
Elise Chandler
,
Kai-Lan Chang
,
Hua Chen
,
Lin Chen
,
Lijing Cheng
,
Vincent Y. S. Cheng
,
Leah Chomiak
,
Hanne H. Christiansen
,
John R. Christy
,
Eui-Seok Chung
,
Laura M. Ciasto
,
Leonardo Clarke
,
Kyle R. Clem
,
Scott Clingan
,
Caio A.S. Coelho
,
Judah L. Cohen
,
Melanie Coldewey-Egbers
,
Steve Colwell
,
Owen R. Cooper
,
Richard C. Cornes
,
Kris Correa
,
Felipe Costa
,
Curt Covey
,
Lawrence Coy
,
Jean-François Créatux
,
Lenka Crhova
,
Theresa Crimmins
,
Meghan F. Cronin
,
Thomas Cropper
,
Molly Crotwell
,
Joshua Culpepper
,
Ana P. Cunha
,
Diego Cusicanqui
,
Rajashree T. Datta
,
Sean M. Davis
,
Veerle De Bock
,
Richard A. M. de Jeu
,
Jos De Laat
,
Bertrand Decharme
,
Doug Degenstein
,
Reynald Delaloye
,
Mesut Demircan
,
Chris Derksen
,
Ricardo Deus
,
K. R. Dhurmea
,
Howard J. Diamond
,
S. Dirkse
,
Dmitry Divine
,
Martin T. Dokulil
,
Markus G. Donat
,
Shenfu Dong
,
Wouter A. Dorigo
,
Caroline Drost Jensen
,
Matthew L. Druckenmiller
,
Paula Drumond
,
Marcel du Plessis
,
Hilary A. Dugan
,
Dashkhuu Dulamsuren
,
Devon Dunmire
,
Robert J. H. Dunn
,
Imke Durre
,
Geoff Dutton
,
Gregory Duveiller
,
Mithat Ekici
,
Alesksandra Elias Chereque
,
M. ElKharrim
,
Howard E. Epstein
,
Jhan-Carlo Espinoza
,
Thomas W. Estilow
,
Nicole Estrella
,
Nicolas Fauchereau
,
Robert S. Fausto
,
Richard A. Feely
,
Chris Fenimore
,
David Fereday
,
Xavier Fettweis
,
vitali E. Fioletov
,
Johannes Flemming
,
Chris Fogarty
,
Ryan L. Fogt
,
Bruce C. Forbes
,
Michael J. Foster
,
Bryan A. Franz
,
Natalie M. Freeman
,
Helen A. Fricker
,
Stacey M. Frith
,
Lucien Froidevaux
,
Gerald V. Frost
,
Steven Fuhrman
,
Martin Füllekrug
,
Catherine Ganter
,
Meng Gao
,
Alex S. Gardner
,
Judith Garforth
,
Jay Garg
,
Sebastian Gerland
,
Badin Gibbes
,
Sarah T. Gille
,
John Gilson
,
Karin Gleason
,
Nadine Gobron
,
Scott J. Goetz
,
Stanley B. Goldenberg
,
Gustavo Goni
,
Steven Goodman
,
Atsushi Goto
,
Jens-Uwe Grooß
,
Alexander Gruber
,
Guojun Gu
,
Charles “Chip” P. Guard
,
S. Hagos
,
Sebastian Hahn
,
Leopold Haimberger
,
Bradley D. Hall
,
Benjamin D. Hamlington
,
Edward Hanna
,
Inger Hanssen-Bauer
,
Daniel S. Harnos
,
Ian Harris
,
Qiong He
,
Richard R. Heim Jr.
,
Sverker Hellström
,
Deborah L. Hemming
,
Stefan Hendricks
,
J. Hicks
,
Hugo G. Hidalgo
,
Martin Hirschi
,
Shu-peng Ho
,
W. Hobbs
,
Robert M. Holmes
,
Robert Holzworth
,
Filip Hrbáček
,
Guojie Hu
,
Zeng-Zhen Hu
,
Boyin Huang
,
Hongjie Huang
,
Dale F. Hurst
,
Iolanda Ialongo
,
Antje Inness
,
Ketil Isaksen
,
Masayoshi Ishii
,
Gerardo Jadra
,
Svetlana Jevrejeva
,
Viju O. John
,
W. Johns
,
Bjørn Johnsen
,
Bryan Johnson
,
Gregory C. Johnson
,
Philip D. Jones
,
Timothy Jones
,
Simon A. Josey
,
G. Jumaux
,
Robert Junod
,
Andreas Kääb
,
K. Kabidi
,
Johannes W. Kaiser
,
Robb S.A. Kaler
,
Lars Kaleschke
,
Viktor Kaufmann
,
Amin Fazl Kazemi
,
Linda M. Keller
,
Andreas Kellerer-Pirklbauer
,
Mike Kendon
,
John Kennedy
,
Elizabeth C. Kent
,
Kenneth Kerr
,
Valentina Khan
,
Mai Van Khiem
,
Richard Kidd
,
Mi Ju Kim
,
Seong-Joong Kim
,
Zak Kipling
,
Philip J. Klotzbach
,
John A. Knaff
,
Akash Koppa
,
Natalia N. Korshunova
,
Benjamin M. Kraemer
,
Natalya A. Kramarova
,
A. C. Kruger
,
Andries Kruger
,
Arun Kumar
,
Michelle L’Heureux
,
Sofia La Fuente
,
Alo Laas
,
Zachary M. Labe
,
Rick Lader
,
Mónika Lakatos
,
Kaisa Lakkala
,
Hoang Phuc Lam
,
Xin Lan
,
Peter Landschützer
,
Chris W. Landsea
,
Timothy Lang
,
Matthias Lankhorst
,
Kathleen O. Lantz
,
Mark J. Lara
,
Waldo Lavado-Casimiro
,
David A. Lavers
,
Matthew A. Lazzara
,
Thierry Leblanc
,
Tsz-Cheung Lee
,
Eric M. Leibensperger
,
Chris Lennard
,
Eric Leuliette
,
Kinson H. Y. Leung
,
Jan L. Lieser
,
Tanja Likso
,
I-I. Lin
,
Jackie Lindsey
,
Yakun Liu
,
Ricardo Locarnini
,
Norman G. Loeb
,
Bryant D. Loomis
,
Andrew M. Lorrey
,
Diego Loyola
,
Rui Lu
,
Rick Lumpkin
,
Jing-Jia Luo
,
Kari Luojus
,
John M. Lyman
,
Stephen C. Maberly
,
Matthew J. Macander
,
Michael MacFerrin
,
Graeme A. MacGilchrist
,
Michelle L. MacLennan
,
Remi Madelon
,
Andrew D. Magee
,
Florence Magnin
,
Jostein Mamen
,
Ken D. Mankoff
,
Gloria L. Manney
,
Izolda Marcinonienė
,
Jose A. Marengo
,
Mohammadi Marjan
,
Ana E. Martínez
,
Robert A. Massom
,
Shin-Ichiro Matsuzaki
,
Linda May
,
Michael Mayer
,
Matthew R. Mazloff
,
Stephanie A. McAfee
,
C. McBride
,
Matthew F. McCabe
,
James W. McClelland
,
Michael J. McPhaden
,
Tim R. Mcvicar
,
Carl A. Mears
,
Walter N. Meier
,
A. Mekonnen
,
Annette Menzel
,
Christopher J. Merchant
,
Mark A. Merrifield
,
Michael F. Meyer
,
Tristan Meyers
,
David E. Mikolajczyk
,
John B. Miller
,
Diego G. Miralles
,
Noelia Misevicius
,
Alexey Mishonov
,
Gary T. Mitchum
,
Ben I. Moat
,
Leander Moesinger
,
Aurel Moise
,
Jorge Molina-Carpio
,
Ghislaine Monet
,
Stephan A. Montzka
,
Twila A. Moon
,
G. W. K. Moore
,
Natali Mora
,
Johnny Morán
,
Claire Morehen
,
Colin Morice
,
A. E. Mostafa
,
Thomas L. Mote
,
Ivan Mrekaj
,
Lawrence Mudryk
,
Jens Mühle
,
Rolf Müller
,
David Nance
,
Eric R. Nash
,
R. Steven Nerem
,
Paul A. Newman
,
Julien P. Nicolas
,
Juan J. Nieto
,
Jeannette Noetzli
,
Ben Noll
,
Taylor Norton
,
Kelsey E. Nyland
,
John O’Keefe
,
Naomi Ochwat
,
Yoshinori Oikawa
,
Yuka Okunaka
,
Timothy J. Osborn
,
James E. Overland
,
Taejin Park
,
Mark Parrington
,
Julia K. Parrish
,
Richard J. Pasch
,
Reynaldo Pascual Ramírez
,
Cécile Pellet
,
Mauri S. Pelto
,
Melita Perčec Tadić
,
Donald K. Perovich
,
Guðrún Nína Petersen
,
Kyle Petersen
,
Irina Petropavlovskikh
,
Alek Petty
,
Alexandre B. Pezza
,
Luciano P. Pezzi
,
Coda Phillips
,
Gareth K. Phoenix
,
Don Pierson
,
Izidine Pinto
,
Vanda Pires
,
Michael Pitts
,
Stephen Po-Chedley
,
Paolo Pogliotti
,
Kristin Poinar
,
Lorenzo Polvani
,
Wolfgang Preimesberger
,
Colin Price
,
Merja Pulkkanen
,
Sarah G. Purkey
,
Bo Qiu
,
Kenny Quisbert
,
Willy R. Quispe
,
M. Rajeevan
,
Andrea M. Ramos
,
William J. Randel
,
Mika Rantanen
,
Marilyn N. Raphael
,
James Reagan
,
Cristina Recalde
,
Phillip Reid
,
Samuel Rémy
,
Alejandra J. Reyes Kohler
,
Lucrezia Ricciardulli
,
Andrew D. Richardson
,
Robert Ricker
,
David A. Robinson
,
M. Robjhon
,
Willy Rocha
,
Matthew Rodell
,
Esteban Rodriguez Guisado
,
Nemesio Rodriguez-Fernandez
,
Vladimir E. Romanovsky
,
Josyane Ronchail
,
Matthew Rosencrans
,
Karen H. Rosenlof
,
Benjamin Rösner
,
Henrieke Rösner
,
Alexei Rozanov
,
Jozef Rozkošný
,
Frans Rubek
,
Olga O. Rusanovskaya
,
This Rutishauser
,
C. T. Sabeerali
,
Roberto Salinas
,
Ahira Sánchez-Lugo
,
Michelle L. Santee
,
Marcelo Santini
,
Katsunari Sato
,
Parnchai Sawaengphokhai
,
A. Sayouri
,
Theodore Scambos
,
Verena Schenzinger
,
Semjon Schimanke
,
Robert W. Schlegel
,
Claudia Schmid
,
Martin Schmid
,
Udo Schneider
,
Carl J. Schreck
,
Cristina Schultz
,
Science Systems and Applications Inc. Science Systems and Applications Inc.
,
Z. T. Segele
,
Serhat Sensoy
,
Shawn P. Serbin
,
Mark C. Serreze
,
Amsari Mudzakir Setiawan
,
Fumi Sezaki
,
Sapna Sharma
,
Jonathan D. Sharp
,
Gay Sheffield
,
Jia-Rui Shi
,
Lei Shi
,
Alexander I. Shiklomanov
,
Nikolay I. Shiklomanov
,
Svetlana V. Shimaraeva
,
R. Shukla
,
David A. Siegel
,
Eugene A. Silow
,
F. Sima
,
Adrian J. Simmons
,
David A. Smeed
,
Adam Smith
,
Sharon L. Smith
,
Brian J. Soden
,
Viktoria Sofieva
,
Everaldo Souza
,
Tim H. Sparks
,
Jacqueline Spence-Hemmings
,
Robert G. M. Spencer
,
Sandra Spillane
,
O. P. Sreejith
,
A. K. Srivastava
,
Paul W. Stackhouse Jr.
,
Sharon Stammerjohn
,
Ryan Stauffer
,
Wolfgang Steinbrecht
,
Andrea K. Steiner
,
Jose L. Stella
,
Tannecia S. Stephenson
,
Pietro Stradiotti
,
Susan E. Strahan
,
Dmitry A. Streletskiy
,
Divya E. Surendran
,
Anya Suslova
,
Tove Svendby
,
William Sweet
,
Kiyotoshi Takahashi
,
Kazuto Takemura
,
Suzanne E. Tank
,
Michael A. Taylor
,
Marco Tedesco
,
Stephen J. Thackeray
,
W. M. Thiaw
,
Emmanuel Thibert
,
Richard L. Thoman
,
Andrew F. Thompson
,
Philip R. Thompson
,
Xiangshan Tian-Kunze
,
Mary-Louise Timmermans
,
Maxim A. Timofeyev
,
Skie Tobin
,
Hans Tømmervik
,
Kleareti Tourpali
,
Lidia Trescilo
,
Mikhail Tretiakov
,
Blair C. Trewin
,
Joaquin A. Triñanes
,
Adrian Trotman
,
Ryan E. Truchelut
,
Luke D. Trusel
,
Mari R. Tye
,
Ronald van der A
,
Robin van der Schalie
,
Gerard van der Schrier
,
Cedric J. Van Meerbeeck
,
Arnold J.H. van vliet
,
Ahad Vazife
,
Piet Verburg
,
Jean-Paul Vernier
,
Isaac J. Vimont
,
Katrina Virts
,
Sebastián Vivero
,
Denis L. Volkov
,
Holger Vömel
,
Russell S. Vose
,
Donald A. Walker
,
John E. Walsh
,
Bin Wang
,
Hui Wang
,
Muyin Wang
,
Ray H. J. Wang
,
Xinyue Wang
,
Rik Wanninkhof
,
Taran Warnock
,
Mark Weber
,
Melinda Webster
,
Adrian Wehrlé
,
Caihong Wen
,
Toby K. Westberry
,
Matthew J. Widlansky
,
David N. Wiese
,
Jeannette D. Wild
,
Jonathan D. Wille
,
An Willems
,
Kate M. Willett
,
Earle Williams
,
J. Willis
,
Takmeng Wong
,
Kimberly M. Wood
,
Richard Iestyn Woolway
,
Ping-Ping Xie
,
Dedi Yang
,
Xungang Yin
,
Ziqi Yin
,
Zhenzhong Zeng
,
Huai-min Zhang
,
Li Zhang
,
Peiqun Zhang
,
Lin Zhao
,
Xinjia Zhou
,
Zhiwei Zhu
,
Jerry R. Ziemke
,
Markus Ziese
,
Scott Zolkos
,
Ruxandra M. Zotta
,
Cheng-Zhi Zou
,
Jessicca Allen
,
Amy V. Camper
,
Bridgette O. Haley
,
Gregory Hammer
,
S. Elizabeth Love-Brotak
,
Laura Ohlmann
,
Lukas Noguchi
,
Deborah B. Riddle
, and
Sara W. Veasey

Abstract

—J. BLUNDEN, T. BOYER, AND E. BARTOW-GILLIES

Earth’s global climate system is vast, complex, and intricately interrelated. Many areas are influenced by global-scale phenomena, including the “triple dip” La Niña conditions that prevailed in the eastern Pacific Ocean nearly continuously from mid-2020 through all of 2022; by regional phenomena such as the positive winter and summer North Atlantic Oscillation that impacted weather in parts the Northern Hemisphere and the negative Indian Ocean dipole that impacted weather in parts of the Southern Hemisphere; and by more localized systems such as high-pressure heat domes that caused extreme heat in different areas of the world. Underlying all these natural short-term variabilities are long-term climate trends due to continuous increases since the beginning of the Industrial Revolution in the atmospheric concentrations of Earth’s major greenhouse gases.

In 2022, the annual global average carbon dioxide concentration in the atmosphere rose to 417.1±0.1 ppm, which is 50% greater than the pre-industrial level. Global mean tropospheric methane abundance was 165% higher than its pre-industrial level, and nitrous oxide was 24% higher. All three gases set new record-high atmospheric concentration levels in 2022.

Sea-surface temperature patterns in the tropical Pacific characteristic of La Niña and attendant atmospheric patterns tend to mitigate atmospheric heat gain at the global scale, but the annual global surface temperature across land and oceans was still among the six highest in records dating as far back as the mid-1800s. It was the warmest La Niña year on record. Many areas observed record or near-record heat. Europe as a whole observed its second-warmest year on record, with sixteen individual countries observing record warmth at the national scale. Records were shattered across the continent during the summer months as heatwaves plagued the region. On 18 July, 104 stations in France broke their all-time records. One day later, England recorded a temperature of 40°C for the first time ever. China experienced its second-warmest year and warmest summer on record. In the Southern Hemisphere, the average temperature across New Zealand reached a record high for the second year in a row. While Australia’s annual temperature was slightly below the 1991–2020 average, Onslow Airport in Western Australia reached 50.7°C on 13 January, equaling Australia's highest temperature on record.

While fewer in number and locations than record-high temperatures, record cold was also observed during the year. Southern Africa had its coldest August on record, with minimum temperatures as much as 5°C below normal over Angola, western Zambia, and northern Namibia. Cold outbreaks in the first half of December led to many record-low daily minimum temperature records in eastern Australia.

The effects of rising temperatures and extreme heat were apparent across the Northern Hemisphere, where snow-cover extent by June 2022 was the third smallest in the 56-year record, and the seasonal duration of lake ice cover was the fourth shortest since 1980. More frequent and intense heatwaves contributed to the second-greatest average mass balance loss for Alpine glaciers around the world since the start of the record in 1970. Glaciers in the Swiss Alps lost a record 6% of their volume. In South America, the combination of drought and heat left many central Andean glaciers snow free by mid-summer in early 2022; glacial ice has a much lower albedo than snow, leading to accelerated heating of the glacier. Across the global cryosphere, permafrost temperatures continued to reach record highs at many high-latitude and mountain locations.

In the high northern latitudes, the annual surface-air temperature across the Arctic was the fifth highest in the 123-year record. The seasonal Arctic minimum sea-ice extent, typically reached in September, was the 11th-smallest in the 43-year record; however, the amount of multiyear ice—ice that survives at least one summer melt season—remaining in the Arctic continued to decline. Since 2012, the Arctic has been nearly devoid of ice more than four years old.

In Antarctica, an unusually large amount of snow and ice fell over the continent in 2022 due to several landfalling atmospheric rivers, which contributed to the highest annual surface mass balance, 15% to 16% above the 1991–2020 normal, since the start of two reanalyses records dating to 1980. It was the second-warmest year on record for all five of the long-term staffed weather stations on the Antarctic Peninsula. In East Antarctica, a heatwave event led to a new all-time record-high temperature of −9.4°C—44°C above the March average—on 18 March at Dome C. This was followed by the collapse of the critically unstable Conger Ice Shelf. More than 100 daily low sea-ice extent and sea-ice area records were set in 2022, including two new all-time annual record lows in net sea-ice extent and area in February.

Across the world’s oceans, global mean sea level was record high for the 11th consecutive year, reaching 101.2 mm above the 1993 average when satellite altimetry measurements began, an increase of 3.3±0.7 over 2021. Globally-averaged ocean heat content was also record high in 2022, while the global sea-surface temperature was the sixth highest on record, equal with 2018. Approximately 58% of the ocean surface experienced at least one marine heatwave in 2022. In the Bay of Plenty, New Zealand’s longest continuous marine heatwave was recorded.

A total of 85 named tropical storms were observed during the Northern and Southern Hemisphere storm seasons, close to the 1991–2020 average of 87. There were three Category 5 tropical cyclones across the globe—two in the western North Pacific and one in the North Atlantic. This was the fewest Category 5 storms globally since 2017. Globally, the accumulated cyclone energy was the lowest since reliable records began in 1981. Regardless, some storms caused massive damage. In the North Atlantic, Hurricane Fiona became the most intense and most destructive tropical or post-tropical cyclone in Atlantic Canada’s history, while major Hurricane Ian killed more than 100 people and became the third costliest disaster in the United States, causing damage estimated at $113 billion U.S. dollars. In the South Indian Ocean, Tropical Cyclone Batsirai dropped 2044 mm of rain at Commerson Crater in Réunion. The storm also impacted Madagascar, where 121 fatalities were reported.

As is typical, some areas around the world were notably dry in 2022 and some were notably wet. In August, record high areas of land across the globe (6.2%) were experiencing extreme drought. Overall, 29% of land experienced moderate or worse categories of drought during the year. The largest drought footprint in the contiguous United States since 2012 (63%) was observed in late October. The record-breaking megadrought of central Chile continued in its 13th consecutive year, and 80-year record-low river levels in northern Argentina and Paraguay disrupted fluvial transport. In China, the Yangtze River reached record-low values. Much of equatorial eastern Africa had five consecutive below-normal rainy seasons by the end of 2022, with some areas receiving record-low precipitation totals for the year. This ongoing 2.5-year drought is the most extensive and persistent drought event in decades, and led to crop failure, millions of livestock deaths, water scarcity, and inflated prices for staple food items.

In South Asia, Pakistan received around three times its normal volume of monsoon precipitation in August, with some regions receiving up to eight times their expected monthly totals. Resulting floods affected over 30 million people, caused over 1700 fatalities, led to major crop and property losses, and was recorded as one of the world’s costliest natural disasters of all time. Near Rio de Janeiro, Brazil, Petrópolis received 530 mm in 24 hours on 15 February, about 2.5 times the monthly February average, leading to the worst disaster in the city since 1931 with over 230 fatalities.

On 14–15 January, the Hunga Tonga-Hunga Ha'apai submarine volcano in the South Pacific erupted multiple times. The injection of water into the atmosphere was unprecedented in both magnitude—far exceeding any previous values in the 17-year satellite record—and altitude as it penetrated into the mesosphere. The amount of water injected into the stratosphere is estimated to be 146±5 Terragrams, or ∼10% of the total amount in the stratosphere. It may take several years for the water plume to dissipate, and it is currently unknown whether this eruption will have any long-term climate effect.

Open access