View stunning SlideShares in full-screen with the new iOS app!Introducing SlideShare for AndroidExplore all your favorite topics in the SlideShare appGet the SlideShare app to Save for Later — even offline
View stunning SlideShares in full-screen with the new Android app!View stunning SlideShares in full-screen with the new iOS app!
CLIMSENS: Constraining totalfeedback of the climate systemby observations and models.Ragnhild Bieltvedt SkeieTerje Berntsen CICERO and University of OsloGunnar Myhre CICEROMagne Aldrin Norwegian Computer CenterMarit Holden Norwegian Computer Center
Climate sensitivity:The equilibrium change in the annual mean global surfacetemperature following a doubling of the atmospheric CO2concentration. IPCC 2007 2
Constraining the climatesensitivity• “Bottom-up” approach. Perturbing the representations of the climate feedbacks in GCM models.• “Observational based” approach. Using historical observations and simple climate models 3
Statistical model:The data:Surface temperature (3 data set, NH and SH averages).Ocean heat content Additative bias/correction for baseline SOI index, Account for El Nino. 8
Statistical modelBayesian approach and a MCMC-algorithm:1. Apriori distributions for parameters and input data.2. Update your model with observations.3. Get posteriori uncertainties for your model parametersand input data. One of them is the climate sensitivity! 9