Global exposure to flooding from the new CMIP6 climate model projections

AbstractEstimates of future flood risk rely on projections from climate models. The relatively few climate models used to analyze future flood risk cannot easily quantify of their associated uncertainties. In this study, we demonstrated that the projected fluvial flood changes estimated by a new generation of climate models, the collectively known as Coupled Model Intercomparison Project Phase 6 (CMIP6), are similar to those estimated by CMIP5. The spatial patterns of the multi-model median signs of change (+ or −) were also very consistent, implying greater confidence in the projections. The model spread changed little over the course of model development, suggesting irreducibility of the model spread due to internal climate variability, and the consistent projections of models from the same institute suggest the potential to reduce uncertainties caused by model differences. Potential global exposure to flooding is projected to be proportional to the degree of warming, and a greater threat is anticipated as populations increase, demonstrating the need for immediate decisions.

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A community diagnostic tool for Chemistry Climate Model Validation

Geoscientific Model Development Discussions ◽

10.5194/gmdd-5-1229-2012 ◽

2012 ◽

Vol 5 (2) ◽

pp. 1229-1261

Author(s):

A. Gettelman ◽

V. Eyring ◽

C. Fischer ◽

H. Shiona ◽

I. Cionni ◽

...

Keyword(s):

Model Validation ◽

Climate Models ◽

Performance Metrics ◽

Climate Model ◽

Model Development ◽

Coupled Model ◽

Technical Note ◽

Complex Evaluation ◽

System User ◽

Intercomparison Project

Abstract. This technical note presents an overview of the Chemistry-Climate Model Validation Diagnostic (CCMVal-Diag) tool for model evaluation. The CCMVal-Diag tool is a flexible and extensible open source package that facilitates the complex evaluation of global models. Models can be compared to other models, ensemble members (simulations with the same model), and/or many types of observations. The tool can also compute quantitative performance metrics. The initial construction and application is to coupled Chemistry-Climate Models (CCMs) participating in CCMVal, but the evaluation of climate models that submitted output to the Coupled Model Intercomparison Project (CMIP) is also possible. The package has been used to assist with analysis of simulations for the 2010 WMO/UNEP Scientific Ozone Assessment and the SPARC Report on the Evaluation of CCMs. The CCMVal-Diag tool is described and examples of how it functions are presented, along with links to detailed descriptions, instructions and source code. The CCMVal-Diag tool is supporting model development as well as quantifying model improvements, both for different versions of individual models and for different generations of community-wide collections of models used in international assessments. The code allows further extensions by different users for different applications and types, e.g. to other components of the Earth System. User modifications are encouraged and easy to perform with a minimum of coding.

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Northern Hemisphere blocking simulation in current climate models: evaluating progress from the Climate Model Intercomparison Project Phase 5 to 6 and sensitivity to resolution

Weather and Climate Dynamics ◽

10.5194/wcd-1-277-2020 ◽

2020 ◽

Vol 1 (1) ◽

pp. 277-292 ◽

Cited By ~ 1

Author(s):

Reinhard Schiemann ◽

Panos Athanasiadis ◽

David Barriopedro ◽

Francisco Doblas-Reyes ◽

Katja Lohmann ◽

...

Keyword(s):

Climate Models ◽

Climate Model ◽

Global Climate ◽

Model Development ◽

Global Climate Models ◽

Assessment Model ◽

Climate Simulation ◽

Cmip5 Models ◽

Model Intercomparison ◽

Intercomparison Project

Abstract. Global climate models (GCMs) are known to suffer from biases in the simulation of atmospheric blocking, and this study provides an assessment of how blocking is represented by the latest generation of GCMs. It is evaluated (i) how historical CMIP6 (Climate Model Intercomparison Project Phase 6) simulations perform compared to CMIP5 simulations and (ii) how horizontal model resolution affects the simulation of blocking in the CMIP6-HighResMIP (PRIMAVERA – PRocess-based climate sIMulation: AdVances in high-resolution modelling and European climate Risk Assessment) model ensemble, which is designed to address this type of question. Two blocking indices are used to evaluate the simulated mean blocking frequency and blocking persistence for the Euro-Atlantic and Pacific regions in winter and summer against the corresponding estimates from atmospheric reanalysis data. There is robust evidence that CMIP6 models simulate blocking frequency and persistence better than CMIP5 models in the Atlantic and Pacific and during winter and summer. This improvement is sizeable so that, for example, winter blocking frequency in the median CMIP5 model in a large Euro-Atlantic domain is underestimated by 33 % using the absolute geopotential height (AGP) blocking index, whereas the same number is 18 % for the median CMIP6 model. As for the sensitivity of simulated blocking to resolution, it is found that the resolution increase, from typically 100 to 20 km grid spacing, in most of the PRIMAVERA models, which are not re-tuned at the higher resolutions, benefits the mean blocking frequency in the Atlantic in winter and summer and in the Pacific in summer. Simulated blocking persistence, however, is not seen to improve with resolution. Our results are consistent with previous studies suggesting that resolution is one of a number of interacting factors necessary for an adequate simulation of blocking in GCMs. The improvements reported in this study hold promise for further reductions in blocking biases as model development continues.

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A community diagnostic tool for chemistry climate model validation

Geoscientific Model Development ◽

10.5194/gmd-5-1061-2012 ◽

2012 ◽

Vol 5 (5) ◽

pp. 1061-1073 ◽

Cited By ~ 9

Author(s):

A. Gettelman ◽

V. Eyring ◽

C. Fischer ◽

H. Shiona ◽

I. Cionni ◽

...

Keyword(s):

Model Validation ◽

Climate Models ◽

Climate Model ◽

Model Development ◽

Coupled Model ◽

Technical Note ◽

The Earth ◽

Complex Evaluation ◽

System User ◽

Intercomparison Project

Abstract. This technical note presents an overview of the Chemistry-Climate Model Validation Diagnostic (CCMVal-Diag) tool for model evaluation. The CCMVal-Diag tool is a flexible and extensible open source package that facilitates the complex evaluation of global models. Models can be compared to other models, ensemble members (simulations with the same model), and/or many types of observations. The initial construction and application is to coupled chemistry-climate models (CCMs) participating in CCMVal, but the evaluation of climate models that submitted output to the Coupled Model Intercomparison Project (CMIP) is also possible. The package has been used to assist with analysis of simulations for the 2010 WMO/UNEP Scientific Ozone Assessment and the SPARC Report on the Evaluation of CCMs. The CCMVal-Diag tool is described and examples of how it functions are presented, along with links to detailed descriptions, instructions and source code. The CCMVal-Diag tool supports model development as well as quantifies model changes, both for different versions of individual models and for different generations of community-wide collections of models used in international assessments. The code allows further extensions by different users for different applications and types, e.g. to other components of the Earth system. User modifications are encouraged and easy to perform with minimum coding.

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Climate model configurations of the ECMWF Integrated Forecast System (ECMWF-IFS cycle 43r1) for HighResMIP

10.5194/gmd-2018-90 ◽

2018 ◽

Cited By ~ 3

Author(s):

Christopher D. Roberts ◽

Retish Senan ◽

Franco Molteni ◽

Souhail Boussetta ◽

Michael Mayer ◽

...

Keyword(s):

Development Strategy ◽

Climate Model ◽

Model Development ◽

Coupled Model ◽

Horizontal Resolution ◽

Ocean Model ◽

Cold Bias ◽

Model Intercomparison ◽

Forecast System ◽

Intercomparison Project

Abstract. This paper presents atmosphere-only and coupled climate model configurations of the European Centre for Medium-Range Weather Forecasts Integrated Forecast System (ECMWF-IFS) for different combinations of ocean and atmosphere resolution. These configurations are used to perform multi-decadal ensemble experiments following the protocols of the High Resolution Model Intercomparison Project (HighResMip) and phase 6 of the Coupled Model Intercomparison Project (CMIP6). These experiments are used to evaluate the sensitivity of major biases in the atmosphere, ocean, and cryosphere to changes in atmosphere and ocean resolution. Climatological surface biases in ECMWF-IFS are relatively insensitive to an increase in atmospheric resolution from ~50 km to ~25 km. However, increasing the horizontal resolution of the atmosphere while maintaining the same vertical resolution enhances the magnitude of a cold bias in the lower stratosphere. In coupled configurations, there is a strong sensitivity to an increase in ocean model resolution from 1° to 0.25°. However, this sensitivity to ocean resolution takes many years to fully manifest and is not apparent in the first year of integration. This result has implications for the ECMWF coupled model development strategy that typically relies on the analysis of biases in short (

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A protocol for calculating basal melt rates in the ISMIP6 Antarctic ice sheet projections

10.5194/tc-2019-277 ◽

2019 ◽

Cited By ~ 3

Author(s):

Nicolas C. Jourdain ◽

Xylar Asay-Davis ◽

Tore Hattermann ◽

Fiammetta Straneo ◽

Helene Seroussi ◽

...

Keyword(s):

Climate Models ◽

Climate Model ◽

Ice Sheet ◽

Coupled Model ◽

Model Intercomparison ◽

Ice Shelf ◽

Simple Formulation ◽

Future Evolution ◽

Calibration Methods ◽

Intercomparison Project

Abstract. Climate model projections have previously been used to compute ice-shelf basal melt rates in ice-sheet models, but the strategies employed – e.g. ocean input, parameterization, calibration technique, and corrections – have varied widely and are often ad-hoc. Here, a methodology is proposed for the calculation of circum-Antarctic basal melt rates for floating ice, based on climate models, that is suitable for ISMIP6, the Ice Sheet Model Intercomparison Project for CMIP6 (6th Coupled Model Intercomparison Project). The past and future evolution of ocean temperature and salinity is derived from a climate model by estimating anomalies with respect to the modern day, which are added to an present-day climatology constructed from existing observational datasets. Temperature and salinity are extrapolated to any position potentially occupied by a simulated ice shelf. A simple formulation is proposed for a basal-melt parameterization in ISMIP6, constrained by the observed temperature climatology, with a quadratic dependency on either the non-local or local thermal forcing. Two calibration methods are proposed: 1) based on the mean Antarctic melt rate (MeanAnt) and 2) based on melt rates near Pine Island's deep grounding line (PIGL). Future Antarctic mean melt rates are an order of magnitude greater in PIGL than in MeanAnt. The PIGL calibration, and the local parameterization, result in more realistic melt rates near grounding lines. PIGL is also more consistent with observations of interannual melt rate variability underneath Pine Island and Dotson ice shelves. This work stresses the need for more physics and less calibration in the parameterizations, and for more observations of hydrographic properties and melt rates at interannual and decadal time scales.

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A protocol for calculating basal melt rates in the ISMIP6 Antarctic ice sheet projections

The Cryosphere ◽

10.5194/tc-14-3111-2020 ◽

2020 ◽

Vol 14 (9) ◽

pp. 3111-3134 ◽

Cited By ~ 1

Author(s):

Nicolas C. Jourdain ◽

Xylar Asay-Davis ◽

Tore Hattermann ◽

Fiammetta Straneo ◽

Hélène Seroussi ◽

...

Keyword(s):

Climate Models ◽

Climate Model ◽

Ice Sheet ◽

Coupled Model ◽

Model Intercomparison ◽

Ice Shelf ◽

Simple Formulation ◽

Future Evolution ◽

Calibration Methods ◽

Intercomparison Project

Abstract. Climate model projections have previously been used to compute ice shelf basal melt rates in ice sheet models, but the strategies employed – e.g., ocean input, parameterization, calibration technique, and corrections – have varied widely and are often ad hoc. Here, a methodology is proposed for the calculation of circum-Antarctic basal melt rates for floating ice, based on climate models, that is suitable for ISMIP6, the Ice Sheet Model Intercomparison Project for CMIP6 (6th Coupled Model Intercomparison Project). The past and future evolution of ocean temperature and salinity is derived from a climate model by estimating anomalies with respect to the modern day, which are added to a present-day climatology constructed from existing observational datasets. Temperature and salinity are extrapolated to any position potentially occupied by a simulated ice shelf. A simple formulation is proposed for a basal melt parameterization in ISMIP6, constrained by the observed temperature climatology, with a quadratic dependency on either the nonlocal or local thermal forcing. Two calibration methods are proposed: (1) based on the mean Antarctic melt rate (MeanAnt) and (2) based on melt rates near Pine Island's deep grounding line (PIGL). Future Antarctic mean melt rates are an order of magnitude greater in PIGL than in MeanAnt. The PIGL calibration and the local parameterization result in more realistic melt rates near grounding lines. PIGL is also more consistent with observations of interannual melt rate variability underneath Pine Island and Dotson ice shelves. This work stresses the need for more physics and less calibration in the parameterizations and for more observations of hydrographic properties and melt rates at interannual and decadal timescales.

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Pliocene Model Intercomparison Project (PlioMIP): experimental design and boundary conditions (Experiment 2)

Geoscientific Model Development ◽

10.5194/gmd-4-571-2011 ◽

2011 ◽

Vol 4 (3) ◽

pp. 571-577 ◽

Cited By ~ 129

Author(s):

A. M. Haywood ◽

H. J. Dowsett ◽

M. M. Robinson ◽

D. K. Stoll ◽

A. M. Dolan ◽

...

Keyword(s):

Experimental Design ◽

Boundary Conditions ◽

Initial Phase ◽

Climate Models ◽

Model Development ◽

Warm Period ◽

Model Intercomparison ◽

Ocean Atmosphere ◽

Intercomparison Project ◽

Fully Coupled

Abstract. The Palaeoclimate Modelling Intercomparison Project has expanded to include a model intercomparison for the mid-Pliocene warm period (3.29 to 2.97 million yr ago). This project is referred to as PlioMIP (the Pliocene Model Intercomparison Project). Two experiments have been agreed upon and together compose the initial phase of PlioMIP. The first (Experiment 1) is being performed with atmosphere-only climate models. The second (Experiment 2) utilises fully coupled ocean-atmosphere climate models. Following on from the publication of the experimental design and boundary conditions for Experiment 1 in Geoscientific Model Development, this paper provides the necessary description of differences and/or additions to the experimental design for Experiment 2.

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The Model Intercomparison Project on the climatic response to Volcanic forcing (VolMIP): Experimental design and forcing input data

10.5194/gmd-2016-68 ◽

2016 ◽

Cited By ~ 2

Author(s):

Davide Zanchettin ◽

Myriam Khodri ◽

Claudia Timmreck ◽

Matthew Toohey ◽

Anja Schmidt ◽

...

Keyword(s):

Climate Models ◽

Climate Model ◽

Initial Conditions ◽

Volcanic Eruptions ◽

Stratospheric Aerosol ◽

Aerosol Layer ◽

Model Intercomparison ◽

Climatic Response ◽

Volcanic Forcing ◽

Intercomparison Project

Abstract. The enhancement of the stratospheric aerosol layer by volcanic eruptions induces a complex set of responses causing global and regional climate effects on a broad range of timescales. Uncertainties exist regarding the climatic response to strong volcanic forcing identified in coupled climate simulations that contributed to the fifth phase of the Climate Model Intercomparison Project (CMIP5). In order to better understand the sources of these model diversities, the model intercomparison project on the climate response to volcanic forcing (VolMIP) has defined a coordinated set of idealized volcanic perturbation experiments to be carried out in alignment with the CMIP6 protocol. VolMIP provides a common stratospheric aerosol dataset for each experiment to eliminate differences in the applied volcanic forcing, and defines a set of initial conditions to determine how internal climate variability contributes to determining the response. VolMIP will assess to what extent volcanically-forced responses of the coupled ocean-atmosphere system are robustly simulated by state-of-the-art coupled climate models and identify the causes that limit robust simulated behavior, especially differences in the treatment of physical processes. This paper illustrates the design of the idealized volcanic perturbation experiments in the VolMIP protocol and describes the common aerosol forcing input datasets to be used.

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Experimental protocol for sealevel projections from ISMIP6 standalone ice sheet models

10.5194/tc-2019-322 ◽

2020 ◽

Cited By ~ 2

Author(s):

Sophie Nowicki ◽

Antony J. Payne ◽

Heiko Goelzer ◽

Helene Seroussi ◽

William H. Lipscomb ◽

...

Keyword(s):

Sea Level ◽

Climate Models ◽

Ice Sheet ◽

Coupled Model ◽

Sea Level Change ◽

Model Intercomparison ◽

Level Change ◽

Ice Sheet Modeling ◽

Emissions Scenarios ◽

Intercomparison Project

Abstract. Projection of the contribution of ice sheets to sea-level change as part of the Coupled Model Intercomparison Project – phase 6 (CMIP6) takes the form of simulations from coupled ice-sheet-climate models and standalone ice sheet models, overseen by the Ice Sheet Model Intercomparison Project for CMIP6 (ISMIP6). This paper describes the experimental setup for process-based sea-level change projections to be performed with standalone Greenland and Antarctic ice sheet models in the context of ISMIP6. The ISMIP6 protocol relies on a suite of polar atmospheric and oceanic CMIP-based forcing for ice sheet models, in order to explore the uncertainty in projected sea-level change due to future emissions scenarios, CMIP models, ice sheet models, and parameterizations for ice-ocean interactions. We describe here the approach taken for defining the suite of ISMIP6 standalone ice sheet simulations, document the experimental framework and implementation, as well as present an overview of the ISMIP6 forcing to be used by participating ice sheet modeling groups.

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How to combine climate models and observations in event attribution?

10.5194/egusphere-egu21-14636 ◽

2021 ◽

Author(s):

Yoann Robin ◽

Aurélien Ribes

Keyword(s):

Bayesian Method ◽

Climate Models ◽

Climate Model ◽

Coupled Model ◽

Model Data ◽

Human Influence ◽

Scale Parameters ◽

Event Attribution ◽

Intercomparison Project ◽

Climate Model Simulations

We describe a statistical method to derive event attribution diagnoses combining climate model simulations and observations. We fit nonstationary Generalized Extreme Value (GEV) distributions to extremely hot temperatures from an ensemble of Coupled Model Intercomparison Project phase 5 (CMIP) models. In order to select a common statistical model, we discuss which GEV parameters have to be nonstationary and which do not. Our tests suggest that the location and scale parameters of GEV distributions should be considered nonstationary. Then, a multimodel distribution is constructed and constrained by observations using a Bayesian method. This new method is applied to the July 2019 French heatwave. Our results show that both the probability and the intensity of that event have increased significantly in response to human influence. Remarkably, we find that the heat wave considered might not have been possible without climate change. Our results also suggest that combining model data with observations can improve the description of hot temperature distribution.

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