Your SlideShare is downloading. ×
0
CLIMSENS: Constraining totalfeedback of the climate systemby observations and models.Ragnhild Bieltvedt SkeieTerje Berntse...
Climate sensitivity:The equilibrium change in the annual mean global surfacetemperature following a doubling of the atmosp...
Constraining the climatesensitivity• “Bottom-up” approach. Perturbing the  representations of the climate feedbacks in  GC...
ΔQ = ΔF - λ ΔTΔQ:   Heat flux in the systemΔF:   Radiative forcingλ:    Climate Feedback ParameterAt equilibrium: ΔQ = 0, ...
Detailed RF calculations:Tropospheric ozone and aerosols   ΔF     Emissions Oslo CTM2 model  RF-calculations              ...
A simple climate model:Energy balance model/Upwelling Diffusion Ocean                                                     ...
Observations• Surface temperature                               ΔT• Ocean heat content                        Levitus, GRL...
Statistical model:The data:Surface temperature (3 data set, NH and SH averages).Ocean heat content                        ...
Statistical modelBayesian approach and a MCMC-algorithm:1. Apriori distributions for parameters and input data.2. Update y...
λIPCC 2007                10
What’s new?• Improved representation of the radiative  forcing history• Longer time period with observations              ...
Upcoming SlideShare
Loading in...5
×

Norwegian climsenssummarydotearth

454

Published on

0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
454
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
1
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Transcript of "Norwegian climsenssummarydotearth"

  1. 1. 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
  2. 2. Climate sensitivity:The equilibrium change in the annual mean global surfacetemperature following a doubling of the atmospheric CO2concentration. IPCC 2007 2
  3. 3. 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
  4. 4. ΔQ = ΔF - λ ΔTΔQ: Heat flux in the systemΔF: Radiative forcingλ: Climate Feedback ParameterAt equilibrium: ΔQ = 0, λ = ΔF2xCO2 / ΔT2xCO2eq 4
  5. 5. Detailed RF calculations:Tropospheric ozone and aerosols ΔF Emissions Oslo CTM2 model RF-calculations IPCC 2007 5
  6. 6. A simple climate model:Energy balance model/Upwelling Diffusion Ocean ΔQ Structure of the model Parametre: Name Unit Value Mixed layer depth m 60 2 Vertical heat diffusivity cm /sec 0.634 Polar parameter - 0.4 Vertical velocity, upwelling rate m/yr 4.0 2 Air-sea heat exchange parameter W/(m K) 16.0 2 Oceanic interhemispheric heat exchange coeff. W/(m K) 3.5 2 Atmospheric interhemispheric heat exchange coeff. W/(m K) 0.0 2 Climate sensitivity K/(Wm ) 0.8 Schlesinger et al. (1992) 6
  7. 7. Observations• Surface temperature ΔT• Ocean heat content Levitus, GRL 2009 IPCC 2007 7
  8. 8. 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
  9. 9. 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
  10. 10. λIPCC 2007 10
  11. 11. What’s new?• Improved representation of the radiative forcing history• Longer time period with observations 11
  1. A particular slide catching your eye?

    Clipping is a handy way to collect important slides you want to go back to later.

×