SPARC Report No.5

SPARC Report N°5 (2010) Chemistry-Climate Model Validation

Edited by V. Eyring, T. Shepherd and D. Waugh

WCRP – 30
WMO/TD – No. 40
SPARC Report No. 5


SPARC, 2010: SPARC CCMVal Report on the Evaluation of Chemistry-Climate Models. V. Eyring, T. Shepherd and D. Waugh (Eds.), SPARC Report No. 5, WCRP-30/2010, WMO/TD – No. 40, available at BibTex Endnote

List of Content  0.2 MB

Executive Summary  0.1 MB

Full report Part I incl. Chapter 7  28 MB

Full report Part II from Chapter 8  30 MB

Table of Content
Executive Summary


Overall Key Findings

Overall Recommendations

Key Findings by Chapter

Recommendations by Chapter

Chapter 1: Introduction 1

1.1 Rationale

1.2 CCMVal concept for model evaluation and analysis

1.3 Quantitative performance metrics

1.4 Progress beyond the state-of-the-art

1.5 Report Structure


Chapter 2: Chemistry Climate Models and Scenarios

2.1 Introduction

2.2 Climate change in CCMVal-2

2.3 Major components of chemistry climate models and their coupling by transport and radiation

2.3.1 Dynamics Dynamical cores and model grids Horizontal diffusion The Quasi-Biennial Oscillation Gravity wave drag

2.3.2 Radiation

2.3.3 Chemistry and composition Stratospheric chemistry Tropospheric chemistry Mesospheric and upper atmospheric chemistry and physics Time-integration of chemical kinetics Photolysis Heterogeneous reactions and PSC microphysics Boundary conditions, emissions and surface sinks

2.3.4 Transport Advection Convective transport and turbulent mixing of chemical species

2.4 CCMVal-2 models and development since CCMVal-1

2.4.1 AMTRAC3 (known as AMTRAC in CCMVal-1)

2.4.2 CAM3.5


2.4.4 CMAM

2.4.5 CNRM-ACM

2.4.6 E39CA (known as E39C in CCMVal-1)

2.4.7 EMAC


2.4.9 LMDZrepro

2.4.10 MRI

2.4.11 SOCOL and NiwaSOCOL

2.4.12 ULAQ

2.4.13 UMETRAC



2.4.16 WACCM

2.5 Definitions of simulations and external forcings

2.5.1 Internal and external modelling uncertainties

2.5.2 CCMVal-2 simulations REF-B0: Year 2000 time-slice simulation REF-B1: Reproducing the past REF-B2: Making Predictions

2.5.3 External forcings SSTs and sea ice Long-lived greenhouse gases and ozone-depleting substances Ozone precursors Stratospheric aerosol surface area densities and direct aerosol-related heating QBO time series Solar irradiance

2.5.4 Deviations from simulation definitions

2.6 Diagnostic output requested for CCMVal-2




Chapter 3: Radiation

3.1 Introduction

3.1.1 Radiative based diagnostics

3.2 Radiative Transfer Parameterizations

3.3 Global mean temperature and temperature trends in CCMs

3.3.1 Global mean temperature climatology

3.3.2 Global mean temperature trends: Past

3.3.3 Global mean temperature trends: Future

3.4 Evaluation of the CCM radiation codes performance

3.4.1 Experimental set-up

3.4.2 Fluxes: Control experiment

3.4.3 Fluxes: Sensitivity experiments

3.4.4 Heating/Cooling rates: Control experiment

3.4.5 Heating/Cooling rates: Sensitivity experiments

3.4.6 Radiation scheme errors and model temperature biases

3.5 Solar signal in CCMs

3.5.1 Experimental Setup

3.5.2 Sensitivity of the solar signal to spectral resolution

3.6 Summary

3.6.1 Summary by model

3.6.2 Overall summary



Chapter 4: Stratospheric Dynamics

4.1 Introduction

4.2 Evaluation data sets and analyses

4.3 Mean climatology

4.3.1 Zonal-mean temperatures and eastward wind

4.3.2 Stationary waves / zonal asymmetries

4.3.3 Brewer-Dobson circulation / tropical upwelling

4.3.4 Heat flux / heat flux-temperature correlations

4.3.5 Polar stratospheric cloud threshold temperatures

4.4 Variability

4.4.1 Extra-tropical variability of the zonal-mean zonal wind

4.4.2 Tropical variability of the zonal-mean zonal wind

4.4.3 Frequency of major stratospheric sudden warmings

4.4.4 Timing of final warmings / winter-summer transition

4.5 Conclusions

4.5.1 Multi-model summary

4.5.2 Summary by model

4.5.3 Quantitative assessment / metrics

4.5.4 Future projections




Chapter 5: Transport

5.1 Introduction

5.2 Transport Diagnostics for the Tropics

5.2.1 Ascent Tape Recorder Phase Speed Ascent from Mean Age Gradients Comparison of Vertical Velocities

5.2.2. Tropical-Midlatitude Mixing Tape Recorder Amplitude Tropical CH4 Vertical Gradient Tropical Mean Age Tropical-Midlatitude N2O PDFs

5.3 Transport Diagnostics for the Extra-tropics

5.3.1 Integrated processes affecting extra-tropical composition Mid-latitude Mean Age Fractional Release of Cly Northern mid-latitude Cly time series N2O annual cycle in the LS Mean age at 60°N/S

5.3.2 Polar processes Antarctic Spring CH4 PDFs Antarctic September N2O profiles Antarctic spring Cly time series

5.4 Stratospheric transport changes in the 21st Century

5.5 Summary

5.5.1 Transport Summaries by Model

5.5.2 Overall CCMVal-2 Model Transport Summary

5.5.3 Summary of 21st century transport changes

5.5.4 Comparison to CCMVal-1 model transport

5.5.5 Requirements for transport credibility



Chapter 6: Stratospheric Chemistry

6.1 Introduction

6.2 Formulation of Chemical Schemes

6.3 Evaluation of CCMs

6.3.1 Evaluation of Photolysis Rates Introduction to PhotoComp PhotoComp 2008 experiments PhotoComp 2008 results and discussion PhotoComp 2008 grading

6.3.2 Evaluation of Radical (Fast) Chemistry (Non Polar Region) Background to photochemical steady state model comparisons Photochemical steady state model results

6.3.3 Evaluation of Reservoir and Long-Lived Chemistry Tracer-tracer correlations Comparison with satellite climatologies Long-term variations

6.3.4 Evaluation of Polar Chemistry Evolution of gas-phase HNO3, H2O, and HCl Surface area density of PSCs Chemical ozone depletion in the polar vortices Meteorological conditions in the polar vortex Evolution of Chemical Ozone Loss in the Polar Vortex Polar Chemical Ozone Depletion vs. PACl and ClOx

6.4 Summary

6.4.1 Summary by model

6.4.2 Overall Summary



Chapter 7: Upper Troposphere and Lower Stratosphere

7.1 Introduction

7.2 Description of observational data sets used for CCM validation

7.2.1 Balloon data

7.2.2 Aircraft data

7.2.3 Satellite data

7.2.4 Meteorological Analyses

7.3 Metrics and Grading

7.3.1 Grading of Mean and Correlative Quantities

7.3.2 Taylor Diagram

7.4 Results: The Tropical UTLS

7.4.1. Cold Point Tropopause Temperature

7.4.2 Lapse Rate Tropopause Pressure

7.4.3 Transport in the TTL

7.4.4 Ozone

7.4.5 Water Vapour

7.4.6 Intra-seasonal Variability/ Waves

7.4.7 Vertical Thermal Structure

7.5 The Extra-tropical UTLS

7.5.1 Dynamical Structure of the Extra-tropical UTLS Zonal mean wind Mass of the Lowermost Stratosphere Extra-tropical Tropopause pressure Extra-tropical Tropopause Inversion Layer

7.5.2 Transport and mixing Tracer seasonal cycles in the ‘background’ Lowermost Stratosphere Meridional Tracer Gradients Normalised Vertical Profi les of CO in Tropopause Coordinates Vertical profi les of O3, H2O and CO relative to the tropopause height Structure of the ExTL

7.5.5 Variability in UTLS ozone

7.6 Trends in the UTLS

7.6.1 Tropical Tropopause Trends

7.6.2 Extra-tropical Tropopause Trends

7.7 Summary and Conclusions

7.7.1 Quantitative metrics

7.7.2 Qualitative Diagnostics Discussion

Tropical Diagnostics

Extra-tropical Diagnostics

7.7.3 Qualitative Model Discussion

7.7.4 Overall Summary



Chapter 8: Natural Variability of Stratospheric Ozone 305

8.1 Introduction

8.2 Data and Methodology

8.2.1 Data

8.2.2 Multiple Linear Regression Analysis

8.3 Annual Cycle in Ozone

8.3.1 Annual cycle at selected locations in the stratosphere

8.3.2 Springtime ozone values

8.3.3 Annual cycle metrics

8.4 Interannual Polar Ozone Variability

8.4.1 Heat flux and column ozone

8.4.2 Temperature and column ozone

8.4.3 Stratospheric annular mode and column ozone

8.5 Solar Cycle

8.5.1 Vertical structure of temperature and ozone signal in the tropics

8.5.2 Latitudinal structure of the solar signal in temperature and ozone

8.6 QBO in Ozone

8.6.1 Equatorial Variability and the QBO signal in the stratosphere

8.6.2 QBO signal in column ozone

8.7 ENSO Signal in Ozone

8.8 Volcanic Aerosols

8.8.1 Global mean temperature response

8.8.2 Vertical temperature response

8.8.3 Ozone response

8.9 Conclusions

8.9.1 Summary by process

8.9.2 Model by model summary



Chapter 9: Long-term projections of stratospheric ozone

9.1 Introduction

9.2 Analysis methods

9.2.1 Multi-Model Time Series Analysis

9.2.2 Multi-linear regression analysis

9.3 Tropical Ozone

9.3.1 From the 2006 WMO assessment:

9.3.2 Further analysis of the CCMVal-1 runs

9.3.3 Tropical TSAM analysis

9.3.4 Multiple linear regression analysis

9.3.5 The effect of upwelling on ozone

9.3.6 Brief summary

9.4 Mid-Latitude Ozone

9.4.1 From the 2006 WMO assessment:

9.4.2 Further analysis of the CCMVal-1 runs

9.4.3 Mid-Latitude TSAM analysis

9.4.4 Multiple linear regression analysis

9.4.5 Brief Summary

9.5 Polar Ozone

9.5.1 From the 2006 WMO assessment:

9.5.2 Further analysis of the CCMVal-1 runs

9.5.3 Polar TSAM analysis

9.5.4 Antarctic ozone hole diagnostics

9.5.5 Brief Summary

9.6 Ozone recovery

9.6.1 From the 2006 WMO assessment:

9.6.2 Further analysis of the CCMVal-1 runs

9.6.3 Recovery based on TSAM analysis

9.6.4 The relationship between O3 and Cly return dates

9.6.5 Ozone recovery as a function of latitude and reference year

9.6.6 The Role of transport in mid-latitude ozone recovery

9.6.7 Brief Summary

9.7 Summary

9.7.1 Summary by Model

9.7.2 Overall Summary



Chapter 10: Effects of the stratosphere on the troposphere

10.1 Introduction

10.2 Validation of tropospheric and stratospheric climate

10.2.1 Multi-model mean comparison

10.2.2 CCMVal-2 performance

10.2.3 CCMVal-2 vs. CCMVal-1

10.2.4 CCMVal-2 vs. CMIP3

10.3 Evaluation of Stratosphere-Troposphere Coupling in Models

10.3.1 Downward propagation of Annular Mode anomalies

10.3.2 Annular mode time scales and predictability

10.4 Simulations of stratospheric influence on the troposphere in the past and future

10.4.1 Dynamical effects Southern Hemisphere Northern Hemisphere

10.4.2 Radiative effects The response of surface UV radiation to stratospheric ozone changes Radiative forcing due to stratospheric ozone changes

10.4.3 Chemical effects Stratosphere-to-troposphere ozone fluxes

10.5 Summary

10.5.1 Summary by Model

10.5.2 Overall Summary



Appendix A: List of Acronyms

Appendix B: Time Series Additive-Model Analysis

B.1 Multi-Model Ensemble Analysis

B.2 Nonparametric estimation of the individual model trends

B.3 Baseline-adjustment of the trend estimates

B.4 Multi-model trend estimates