CIRCULATES - Circulation, Clouds and Climate Sensitivity
Lead Research Organisation:
UNIVERSITY OF EXETER
Department Name: Mathematics
Abstract
Climate models are numerical models used to make projections of future climate change. Because of limitations in computing power, approximations to some parts of the model are required, particularly on small scales where important processes occur that are smaller than the model grid on which calculations are carried out. It is not clear how best to approximate small-scale processes and as a result, different GCMs use different approximations and produce different predictions of future climate change. One of the most important of these uncertainties is how low clouds are represented, and that is the focus of the CIRCULATES proposal.
We now have access to new, high resolution satellite observations that we can use to build datasets that give us a much better idea of how clouds form and disperse, and how they interact with the environment in which they find themselves. We also have high resolution modelling tools that are able to represent the physical processes necessary to simulate clouds with much higher accuracy. High resolution models are far too computationally expensive to run for many model years over the whole globe in a way that could be used to project changes in climate directly. However, in conjunction with the satellite data, they can be used to determine the best way to represent the effects of clouds on the GCM model grid. This information can be transferred to the climate model, which can then be run to discover the impact of our findings on global climate change. In CIRCULATES, we propose to develop both new satellite data and high resolution simulations that are specifically designed to assist with improving and understanding the response of climate models with a focus on tropical and sub-tropical clouds.
The project aims to assist the climate science and policy communities in two ways. First, the discoveries that we make will be used to assess the simulations made by climate models run by modelling centres around the world for the Intergovernmental Panel on Climate Change (IPCC) reports. How well are IPCC GCMs representing cloud processes in the present day? How does their representation change for simulations of the future and is this appropriate? By determining the fidelity of simulation in comparison with high resolution satellite and model data, we will determine the extent to which model simulations can be trusted, with the aim of constraining the likely range of future climate change. Second, we will develop metrics that are useful not only for constraining projections but also for model developers who are building the next generation of models. Our project has strong collaboration with the Met Office, who, together with the academic community, are the primary developers of models used for understanding climate change in the UK. We will engage with key Met Office and UKESM staff on a regular basis in order to determine how our results may be made most useful to model development.
We now have access to new, high resolution satellite observations that we can use to build datasets that give us a much better idea of how clouds form and disperse, and how they interact with the environment in which they find themselves. We also have high resolution modelling tools that are able to represent the physical processes necessary to simulate clouds with much higher accuracy. High resolution models are far too computationally expensive to run for many model years over the whole globe in a way that could be used to project changes in climate directly. However, in conjunction with the satellite data, they can be used to determine the best way to represent the effects of clouds on the GCM model grid. This information can be transferred to the climate model, which can then be run to discover the impact of our findings on global climate change. In CIRCULATES, we propose to develop both new satellite data and high resolution simulations that are specifically designed to assist with improving and understanding the response of climate models with a focus on tropical and sub-tropical clouds.
The project aims to assist the climate science and policy communities in two ways. First, the discoveries that we make will be used to assess the simulations made by climate models run by modelling centres around the world for the Intergovernmental Panel on Climate Change (IPCC) reports. How well are IPCC GCMs representing cloud processes in the present day? How does their representation change for simulations of the future and is this appropriate? By determining the fidelity of simulation in comparison with high resolution satellite and model data, we will determine the extent to which model simulations can be trusted, with the aim of constraining the likely range of future climate change. Second, we will develop metrics that are useful not only for constraining projections but also for model developers who are building the next generation of models. Our project has strong collaboration with the Met Office, who, together with the academic community, are the primary developers of models used for understanding climate change in the UK. We will engage with key Met Office and UKESM staff on a regular basis in order to determine how our results may be made most useful to model development.
Planned Impact
Constraints on cloud feedback are directly relevant to climate policy worldwide. The project is in an excellent position to achieve this through the following linked activities.
The CIRCULATES team are engaged with United Nations agencies through several initiatives. Co-Is Collins and Byrne are authors of the forthcoming IPCC Sixth Assessment Report (AR6 - including special reports). Project partner Webb is a steering committee member for the World Climate Research Programme (WCRP) Grand Challenge on Clouds, Circulation and Climate Sensitivity and is co-lead author of the WCRP Assessment on Climate Sensitivity. CIRCULATES will therefore be able to feed directly into policy processes at international level.
Nationally, CIRCULATES will engage with the UK Climate Projections (UKCP) process by analysing data from the simulations used to make projections and applying our constraint metrics to them. This will help ensure that the Met Office and UK policy makers have the best information available for making decisions regarding climate change impacts.
More specifically, the project partner, the Met Office, will benefit directly from the research. Simulations and numerical model coding will be carried out using Met Office systems, meaning that results and code development will be directly relevant to Met Office work. We plan frequent informal meetings with relevant Met Office staff in the areas of model development, cloud and climate feedback and model projection, facilitated by the close proximity of the Met Office and the University of Exeter. Met Office staff will be present at our annual meetings and at the special model development workshop we plan for year 3. Transfer and relevance of this impact will be ensured through the direct involvement of Met Office staff in the project: Webb as partner, and Ringer and Stirling as strategic panel members.
The CIRCULATES team are engaged with United Nations agencies through several initiatives. Co-Is Collins and Byrne are authors of the forthcoming IPCC Sixth Assessment Report (AR6 - including special reports). Project partner Webb is a steering committee member for the World Climate Research Programme (WCRP) Grand Challenge on Clouds, Circulation and Climate Sensitivity and is co-lead author of the WCRP Assessment on Climate Sensitivity. CIRCULATES will therefore be able to feed directly into policy processes at international level.
Nationally, CIRCULATES will engage with the UK Climate Projections (UKCP) process by analysing data from the simulations used to make projections and applying our constraint metrics to them. This will help ensure that the Met Office and UK policy makers have the best information available for making decisions regarding climate change impacts.
More specifically, the project partner, the Met Office, will benefit directly from the research. Simulations and numerical model coding will be carried out using Met Office systems, meaning that results and code development will be directly relevant to Met Office work. We plan frequent informal meetings with relevant Met Office staff in the areas of model development, cloud and climate feedback and model projection, facilitated by the close proximity of the Met Office and the University of Exeter. Met Office staff will be present at our annual meetings and at the special model development workshop we plan for year 3. Transfer and relevance of this impact will be ensured through the direct involvement of Met Office staff in the project: Webb as partner, and Ringer and Stirling as strategic panel members.
Organisations
- UNIVERSITY OF EXETER (Lead Research Organisation)
- Meteorological Office UK (Collaboration)
- Rutherford Appleton Laboratory (Collaboration)
- UNIVERSITY OF READING (Collaboration)
- University of St Andrews (Collaboration)
- UK CENTRE FOR ECOLOGY & HYDROLOGY (Collaboration)
- IMPERIAL COLLEGE LONDON (Collaboration)
Publications
Hill P
(2023)
Climate Models Underestimate Dynamic Cloud Feedbacks in the Tropics
in Geophysical Research Letters
Liu Q
(2021)
SimCloud version 1.0: a simple diagnostic cloud scheme for idealized climate models
in Geoscientific Model Development
McKim B
(2021)
Joint Dependence of Longwave Feedback on Surface Temperature and Relative Humidity
in Geophysical Research Letters
Vallis G
(2020)
Convective organization and eastward propagating equatorial disturbances in a simple excitable system
in Quarterly Journal of the Royal Meteorological Society
Vallis G
(2020)
The Trouble with Water: Condensation, Circulation and Climate
in The European Physical Journal Plus
Description | CloudSENSE |
Amount | £500,000 (GBP) |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 02/2021 |
End | 02/2025 |
Title | Reduction in the Tropical High Cloud Fraction in Response to an Indirect Weakening of the Hadley Cell |
Description | NetCDF files for figures in "Reduction in the Tropical High Cloud Fraction in Response to an Indirect Weakening of the Hadley Cell" submitted to Journal of Advances in Modeling Earth Systems. Figure 1: Prescribed SST for control and perturbed simulations: sst_ctrl_annualzonalmeans.nc sst_pert_annualzonalmeans.nc Figure 2: Mass meridional stream function data for control and perturbed simulations: Figure 2a: PC2 cloud scheme + Gregory-Rowntree mass-flux convection scheme mmsf_pc2gr_ctrl_annualmeans.nc mmsf_pc2gr_pert_annualmeans.nc Figure 2b: Smith cloud scheme + Gregory-Rowntree mass-flux convection scheme mmsf_smithgr_ctrl_annualmeans.nc mmsf_smithgr_pert_annualmeans.nc Figure 3a: Ice cloud fraction data for control and perturbed simulations with PC2 cloud scheme (zonal and time-mean over 15 simulation years) Cf_pc2gr_ctrl_annualzonalmeans.nc Cf_pc2gr_pert_annualzonalmeans.nc Figure 3b: Ice cloud fraction data for control and perturbed simulations with Smith cloud scheme (zonal and time-mean over 15 simulation years) Cf_smithgr_ctrl_annualzonalmeans.nc Cf_smithgr_pert_annualzonalmeans.nc Figure 3c: Relative humidity data for control and perturbed simulations with PC2 cloud scheme (zonal and time-mean over 15 simulation years) RH_pc2gr_ctrl_annualzonalmeans.nc RH_pc2gr_pert_annualzonalmeans.nc Figure 3d: Relative humidity for control and perturbed simulations with Smith cloud scheme (zonal and time-mean over 15 simulation years) RH_smithgr_ctrl_annualzonalmeans.nc RH_smithgr_pert_annualzonalmeans.nc Figure 3e: Specific humidity data for control and perturbed simulations with PC2 cloud scheme (zonal and time-mean over 15 simulation years) q_pc2gr_ctrl_annualzonalmeans.nc q_pc2gr_pert_annualzonalmeans.nc Figure 3f: Specific humidity data for control and perturbed simulations with Smith cloud scheme (zonal and time-mean over 15 simulation years) q_smithgr_ctrl_annualzonalmeans.nc q_smithgr_pert_annualzonalmeans.nc Figure 3g: Temperature data for control and perturbed simulations with PC2 cloud scheme (zonal and time-mean over 15 simulation years) T_pc2gr_ctrl_annualzonalmeans.nc T_pc2gr_pert_annualzonalmeans.nc Figure 3h: Temperature data for control and perturbed simulations with Smith cloud scheme (zonal and time-mean over 15 simulation years) T_smithgr_ctrl_annualzonalmeans.nc T_smithgr_pert_annualzonalmeans.nc Figure 5: Control and perturbed simulation data for ice cloud fraction and mass fraction of ice cloud condensates meaned over the tropical ascent region for PC2 scheme Cf_pc2gr_ctrl_annualzonalmeans_15yrs_tropicalascent.nc Cf_pc2gr_pert_annualzonalmeans_15yrs_tropicalascent.nc qcf_pc2gr_ctrl_annualzonalmeans_15yrs_tropicalascent.nc qcf_pc2gr_pert_annualzonalmeans_15yrs_tropicalascent.nc Figure 6a,b: Monthly-mean data of convective mass flux for control and perturbed simulations over the tropics between \(\pm\) 31 \(^\circ\)N for PC2 cloud scheme convmassflux_pc2gr_ctrl_monthlymean_15yrs_tropics.nc convmassflux_pc2gr_pert_monthlymean_15yrs_tropics.nc Figure 6c,d: Monthly-mean data of net convective detrainment for control and perturbed simulations over the tropics between \(\pm\) 31 \(^\circ\)N for PC2 cloud scheme netconvdetrain_pc2gr_ctrl_monthlymean_15yrs_tropics.nc netconvdetrain_pc2gr_pert_monthlymean_15yrs_tropics.nc Figure 6e,f: Monthly-mean data of tendency of ice cloud condensates due to convection for control and perturbed simulations over the tropics between \(\pm\) 31 \(^\circ\)N for PC2 cloud scheme dqcfdtconv_pc2gr_ctrl_monthlymean_15yrs_tropics.nc dqcfdtconv_pc2gr_pert_monthlymean_15yrs_tropics.nc Figure 7: Annual and zonal-mean data of net convective detrainment for control and perturbed simulations over the tropical ascent regoin between \(\pm\) 7 \(^\circ\)N for PC2 cloud scheme netconvdetrain_pc2gr_ctrl_annualzonalmeans_15yrs_tropicalascent.nc netconvdetrain_pc2gr_pert_annualzonalmeans_15yrs_tropicalascent.nc Figure 8: Annual and zonal-mean data of net convective detrainment and ice cloud fraction for control and perturbed simulations over the tropical ascent regoin between \(\pm\) 7 \(^\circ\)N for PC2 cloud scheme netconvdetrain_pc2gr_ctrl_annualzonalmeans_15yrs_tropicalascent.nc netconvdetrain_pc2gr_pert_annualzonalmeans_15yrs_tropicalascent.nc Cf_pc2gr_ctrl_annualzonalmeans_15yrs_tropicalascent.nc Cf_pc2gr_pert_annualzonalmeans_15yrs_tropicalascent.nc Figure 9: Annual and zonal-mean data of convective tendency of mass fraction of ice cloud condensates for control and perturbed simulations over the tropical ascent regoin between \(\pm\) 7 \(^\circ\)N for PC2 cloud scheme dqcfdtconv_pc2gr_ctrl_annualzonalmeans_15yrs_tropicalascent.nc dqcfdtconv_pc2gr_pert_annualzonalmeans_15yrs_tropicalascent.nc Figure 10: Annual and zonal-mean data of net depositional tendency of mass fraction of ice cloud condensates for control and perturbed simulations over the tropical ascent regoin between \(\pm\) 7 \(^\circ\)N for PC2 cloud scheme dqcfdtnetdep_pc2gr_ctrl_annualzonalmeans_15yrs_tropicalascent.nc dqcfdtnetdep_pc2gr_pert_annualzonalmeans_15yrs_tropicalascent.nc Figure 11: Monthly-mean data of net depositional tendency of mass fraction of ice cloud condensates for control and perturbed simulations over the tropics between \(\pm\) 31\(^\circ\)N for PC2 cloud scheme dqcfdtnetdep_pc2gr_ctrl_monthlymean_15yrs_tropics.nc dqcfdtnetdep_pc2gr_pert_monthlymean_15yrs_tropics.nc Figure 12: Annual and zonal-mean data of specific humidity and advective tendency for specific humidity for control and perturbed simulations over the tropical ascent regoin between \(\pm\) 7 \(^\circ\)N for PC2 cloud scheme q_pc2gr_ctrl_annualzonalmeans_15yrs_tropicalascent.nc q_pc2gr_pert_annualzonalmeans_15yrs_tropicalascent.nc dqdtadv_pc2gr_ctrl_annualzonalmeans_15yrs_tropicalascent.nc dqdtadv_pc2gr_pert_annualzonalmeans_15yrs_tropicalascent.nc Figure 13: Control and perturbed simulation data for mean vertical advection of moisture, mean vertical moisture convergence, total advection of moisture, and total moisture convergence (meaned over the tropical ascent region for PC2 scheme for 15 simulation years) MeanVerticalAdvectionOfMoisture_pc2gr_ctrl_15yrmean_tropicalascent_vertprof.nc MeanVerticalAdvectionOfMoisture_pc2gr_pert_15yrmean_tropicalascent_vertprof.nc MeanVerticalMoistureConvergence_pc2gr_ctrl_15yrmean_tropicalascent_vertprof.nc MeanVerticalMoistureConvergence_pc2gr_pert_15yrmean_tropicalascent_vertprof.nc TotalMoistureAdvection_pc2gr_ctrl_15yrmean_tropicalascent_vertprof.nc TotalMoistureAdvection_pc2gr_pert_15yrmean_tropicalascent_vertprof.nc TotalMoistureConvergence_pc2gr_ctrl_15yrmean_tropicalascent_vertprof.nc TotalMoistureConvergence_pc2gr_pert_15yrmean_tropicalascent_vertprof.nc |
Type Of Material | Database/Collection of data |
Year Produced | 2023 |
Provided To Others? | Yes |
Impact | This dataset supports a submitted publication that is close to acceptance: Natchiar, S. R. M., M. J. Webb, F. H. Lambert, G. K. Vallis, C. J. Morcrette, C. E. Holloway and D. E. Sergeev, Reduction in the Tropical High Cloud Fraction in Response to an Indirect Weakening of the Hadley Cell, submitted to JAMES, 2023. |
URL | https://zenodo.org/record/8273592 |
Description | Multi-partner collaboration on CIRCULATES. |
Organisation | Imperial College London |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | CIRCULATES is a partnership between Exeter, Reading, St Andrews, Imperial College London, CEH Wallingford, the Met Office and Rutherford Appleton. All partners collaborate via meetings. The collaboration on modelling between Exeter, Reading, St Andrews and the Met Office is particularly strong. Exeter contributes low resolution simulations for comparison with high resolution simulations produced by other partners. Exeter also contributes interpretation of results and leadership. |
Collaborator Contribution | Reading and St Andrews contribute high resolution model simulations and expertise in their interpretation during regular meetings. The Met Office contributes expertise in the use of the Met Office unified model -- which is the model used for the simulations. Other partners such as RAL and Imperial are contributing to the discussion of and development of observed products for use by the other partners. |
Impact | Pending. |
Start Year | 2021 |
Description | Multi-partner collaboration on CIRCULATES. |
Organisation | Meteorological Office UK |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | CIRCULATES is a partnership between Exeter, Reading, St Andrews, Imperial College London, CEH Wallingford, the Met Office and Rutherford Appleton. All partners collaborate via meetings. The collaboration on modelling between Exeter, Reading, St Andrews and the Met Office is particularly strong. Exeter contributes low resolution simulations for comparison with high resolution simulations produced by other partners. Exeter also contributes interpretation of results and leadership. |
Collaborator Contribution | Reading and St Andrews contribute high resolution model simulations and expertise in their interpretation during regular meetings. The Met Office contributes expertise in the use of the Met Office unified model -- which is the model used for the simulations. Other partners such as RAL and Imperial are contributing to the discussion of and development of observed products for use by the other partners. |
Impact | Pending. |
Start Year | 2021 |
Description | Multi-partner collaboration on CIRCULATES. |
Organisation | Rutherford Appleton Laboratory |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | CIRCULATES is a partnership between Exeter, Reading, St Andrews, Imperial College London, CEH Wallingford, the Met Office and Rutherford Appleton. All partners collaborate via meetings. The collaboration on modelling between Exeter, Reading, St Andrews and the Met Office is particularly strong. Exeter contributes low resolution simulations for comparison with high resolution simulations produced by other partners. Exeter also contributes interpretation of results and leadership. |
Collaborator Contribution | Reading and St Andrews contribute high resolution model simulations and expertise in their interpretation during regular meetings. The Met Office contributes expertise in the use of the Met Office unified model -- which is the model used for the simulations. Other partners such as RAL and Imperial are contributing to the discussion of and development of observed products for use by the other partners. |
Impact | Pending. |
Start Year | 2021 |
Description | Multi-partner collaboration on CIRCULATES. |
Organisation | UK Centre for Ecology & Hydrology |
Country | United Kingdom |
Sector | Public |
PI Contribution | CIRCULATES is a partnership between Exeter, Reading, St Andrews, Imperial College London, CEH Wallingford, the Met Office and Rutherford Appleton. All partners collaborate via meetings. The collaboration on modelling between Exeter, Reading, St Andrews and the Met Office is particularly strong. Exeter contributes low resolution simulations for comparison with high resolution simulations produced by other partners. Exeter also contributes interpretation of results and leadership. |
Collaborator Contribution | Reading and St Andrews contribute high resolution model simulations and expertise in their interpretation during regular meetings. The Met Office contributes expertise in the use of the Met Office unified model -- which is the model used for the simulations. Other partners such as RAL and Imperial are contributing to the discussion of and development of observed products for use by the other partners. |
Impact | Pending. |
Start Year | 2021 |
Description | Multi-partner collaboration on CIRCULATES. |
Organisation | University of Reading |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | CIRCULATES is a partnership between Exeter, Reading, St Andrews, Imperial College London, CEH Wallingford, the Met Office and Rutherford Appleton. All partners collaborate via meetings. The collaboration on modelling between Exeter, Reading, St Andrews and the Met Office is particularly strong. Exeter contributes low resolution simulations for comparison with high resolution simulations produced by other partners. Exeter also contributes interpretation of results and leadership. |
Collaborator Contribution | Reading and St Andrews contribute high resolution model simulations and expertise in their interpretation during regular meetings. The Met Office contributes expertise in the use of the Met Office unified model -- which is the model used for the simulations. Other partners such as RAL and Imperial are contributing to the discussion of and development of observed products for use by the other partners. |
Impact | Pending. |
Start Year | 2021 |
Description | Multi-partner collaboration on CIRCULATES. |
Organisation | University of St Andrews |
Country | United Kingdom |
Sector | Academic/University |
PI Contribution | CIRCULATES is a partnership between Exeter, Reading, St Andrews, Imperial College London, CEH Wallingford, the Met Office and Rutherford Appleton. All partners collaborate via meetings. The collaboration on modelling between Exeter, Reading, St Andrews and the Met Office is particularly strong. Exeter contributes low resolution simulations for comparison with high resolution simulations produced by other partners. Exeter also contributes interpretation of results and leadership. |
Collaborator Contribution | Reading and St Andrews contribute high resolution model simulations and expertise in their interpretation during regular meetings. The Met Office contributes expertise in the use of the Met Office unified model -- which is the model used for the simulations. Other partners such as RAL and Imperial are contributing to the discussion of and development of observed products for use by the other partners. |
Impact | Pending. |
Start Year | 2021 |
Description | Met Office Climate Feedback Working Group |
Form Of Engagement Activity | A formal working group, expert panel or dialogue |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Professional Practitioners |
Results and Impact | The Met Office has established the "Climate Feedbacks working group" to understand the origin of radiative feedback and climate sensitivity in the Met Office UM, which is the numerical model used to make weather and climate forecasts in the UK. CIRCULATES has been invited to engage in the meeting, both to inform our own work, but also to share our results and discuss their impact on our understanding as well as possible future model development at the Met Office. |
Year(s) Of Engagement Activity | 2023 |