FN Archimer Export Format
PT J
TI How many modes are needed to predict climate bifurcations? Lessons from an experiment
BT 
AF Dubrulle, Bérengère
   Daviaud, François
   Faranda, Davide
   Marié, Louis
   Saint-Michel, Brice
AS 1:1;2:1;3:2,3,4;4:5;5:6;
FF 1:;2:;3:;4:PDG-ODE-LOPS-OC;5:;
C1 Université Paris-Saclay, CEA, CNRS, SPEC, CEA Saclay 91191 Gif-sur-Yvette CEDEX, France
   Laboratoire des Sciences du Climat et de l’Environnement, UMR 8212 CEA-CNRS-UVSQ, Université Paris-Saclay, IPSL, 91191 Gif-sur-Yvette CEDEX, France
   London Mathematical Laboratory, 8 Margravine Gardens, London, W6 8RH, UK
   Laboratoire de Météorologie Dynamique/Institut Pierre Simon Laplace, Ecole Normale Superieure, PSL research University, 75005 Paris, France
   LOPS, UMR6523, Univ. Brest, CNRS, IFREMER, IRD, 29280 Plouzané, France
   Department of Chemical Engineering, Delft University of Technology, Van der Maasweg 9, 2629HZ, Delft, the Netherlands
C2 CEA, FRANCE
   IPSL LSCE, FRANCE
   LONDON MATHEMATICAL LAB, UK
   IPSL, FRANCE
   IFREMER, FRANCE
   UNIV DELFT, NETHERLANDS
SI BREST
SE PDG-ODE-LOPS-OC
UM LOPS
IN WOS Ifremer UMR
   DOAJ
   copubli-france
   copubli-europe
IF 2.2
TC 6
UR https://archimer.ifremer.fr/doc/00752/86446/91766.pdf
   https://archimer.ifremer.fr/doc/00752/86446/91767.pdf
LA English
DT Article
AB According to everyone's experience, predicting the weather reliably over more than 8 d seems an impossible task for our best weather agencies. At the same time, politicians and citizens are asking scientists for climate projections several decades into the future to guide economic and environmental policies, especially regarding the maximum admissible emissions of CO2. To what extent is this request scientifically admissible? In this review we will investigate this question, focusing on the topic of predictions of transitions between metastable states of the atmospheric or oceanic circulations. Two relevant examples are the switching between zonal and blocked atmospheric circulation at mid-latitudes and the alternation of El Niño and La Niña phases in the Pacific Ocean. The main issue is whether present climate models, which necessarily have a finite resolution and a smaller number of degrees of freedom than the actual terrestrial system, are able to reproduce such spontaneous or forced transitions. To do so, we will draw an analogy between climate observations and results obtained in our group on a laboratory-scale, turbulent, von Kármán flow in which spontaneous transitions between different states of the circulation take place. We will detail the analogy, investigate the nature of the transitions and the number of degrees of freedom that characterize the latter, and discuss the effect of reducing the number of degrees of freedom in such systems. We will also discuss the role of fluctuations and their origin and stress the importance of describing very small scales to capture fluctuations of correct intensity and scale. 
PY 2022
PD FEB
SO Nonlinear Processes In Geophysics
SN 1023-5809
PU Copernicus GmbH
VL 29
IS 1
UT 000758100700001
BP 17
EP 35
DI 10.5194/npg-29-17-2022
ID 86446
ER

EF