# Presentation: 858643

## Model-predicted vertical temperature change

- Joyce E. Penner1
- Minghuai Wang1, Leon Rotstayn2
- 1University of Michigan, 2CSIRO
- Thanks to Ben Santer and Warren Washington for PCM model results

## Observed trend (oK/decade) at surface and mid-troposphere (1979 - 2003)

- Can model-predicted
- tropospheric temperatures
- explain the observed
- patterns of temperature
- change at the surface
- and mid-troposphere?

## Ideally, model-predicted temperature change should include all known forcings

- Present study does not include land-use change, solar

## Effect of forcing on pattern of temperature change is approximated

- CSIRO model run to steady state using a q-flux ocean model for present day (PD) and pre-industrial (PI) forcings
- Effect of temperature change for 1979 - 1999 is approximated using NCAR PCM transient model simulations

## Simulations: CSIRO model

- Fossil fuel soot:  	F = 0.34       	0.13
- Biomass smoke:	F = -0.02      	-0.04
- FF SO4 :		 	F = -0.26		-0.29
- Indirect FF SO4	F = -1.2
- 2xCO2 :			F =  4.4
- O3  :			(in process)
- 					approximate using PCM

- Forcing	Relaxed
- (Wm -2) 	forcing (Wm-2)

## Zonal average temperature change (CSIRO Q-flux ocean model)

## GHG patterns for channel 2; 595 hPa

- PCM model GHG response is
- larger in tropics

- Scale CSIRO by   (2.5/4.4)
- 		x  (0.18/0.71)
- 		x   0.8

## Aerosol patterns for channel 2; 595 hPa

- Scale aerosol patterns by:
- (0.016/0.36)
- Consider no indirect,
- 	   1 x indirect
- 	   2 x indirect

## O3 trend from PCM model (Channel 2 only)

## Surface temperature change CSIRO PD-PI

## 595 temperature CSIRO PD-PI

## 595 temperature CSIRO PD-PI + PCM O3

## Surface - 595 temperature CSIRO PD-PI + PCM O3

## Global average trend (oK/decade)

|  |  
Surface  |  
595  | Surface – 595   |
| --- | --- | --- | --- |
| Observed  | 0.18  | 0.11  | 0.04  |
| FF+BB+SO4(Direct-only) +GHG  | 0.34  | 0.4  | -0.05  |
| FF+BB+SO4(Direct-only) +GHG+O3  | (0.34)  | 0.34  | 0.00  |
| FF+BB+SO4(Direct+Indirect) +GHG  | 0.29  | 0.34  | -0.04  |
| FF+BB+SO4(Direct+Indirect) +GHG+O3  | (0.29)  | 0.28 | 0.01  |
| FF+BB+SO4(Direct+2Indirect) +GHG  | 0.23  | 0.27  | -0.04  |
| FF+BB+SO4(Direct+2Indirect) +GHG+O3  | (0.23)  | 0.21  | 0.02  |

## Caveats

- Results are sensitive to altitude of fossil fuel soot and biomass smoke
- The forcing by fossil fuel soot and biomass aerosols is probably more uncertain than evaluated in IPCC [2001]

## Caveat: Results are sensitive to altitude of both fossil fuel soot and biomass smoke:

## The forcing by fossil fuel soot is probably more uncertain than evaluated in IPCC [2001]

- Hansen [2002]
- Jacobson [2001, 2002]4
- Penner et al. [2003]
- Lohmann and Feichter [2001]
- Lohmann et al. [2000]
-        	 4Inferred

- Direct                    Direct 		                 +Indirect
- (W/m2)                  (W/m2)
- 0.8 		         NA
- 0.27		         0.51
- 0.071		         0.011
- NA		        -1.32
- NA   		        -0.93
- 1Includes OM
- 2For BC>2 mg/m2 all BC, OM and sulfate
- 3Includes biomass + fossil BC+OM

## Uncertainty from fossil fuel direct and indirect soot aerosol effects 

## Recent forcing uncertainties associated with biomass aerosols

- Biomass, mid-troposphere
- Biomass, surface
- All aerosols

- Direct + Indirect
- Forcing (W/m2)
- -1.71
- -0.82
- -2.0 to –2.9

- from Penner et al., 2003

## Total uncertainty associated with warm-cloud indirect aerosols in global models

## Conclusions

- Current results are not consistent with the pattern of temperature change, but there is enough uncertainty in estimated forcing (and emissions) that this is not a strong conclusion