scholarly journals A New End-to-End Workflow for the Community Earth System Model (version 2.0) for CMIP6

2020 ◽  
Author(s):  
Sheri Mickelson ◽  
Alice Bertini ◽  
Gary Strand ◽  
Kevin Paul ◽  
Eric Nienhouse ◽  
...  
Keyword(s):  
Coupled Model ◽  
System Model ◽  
Model Intercomparison ◽  
Phase 3 ◽  
Atmospheric Research ◽  
Previous Generation ◽  
Community Earth System Model ◽  
Intercomparison Project ◽  
Version 2.0 ◽  
New Generation

Abstract. The complexity of each Coupled Model Intercomparison Project grows with every new generation. The Phase 5 effort saw a large increase in the number of experiments that were performed and the number of variables that were requested compared to its previous generation, Phase 3. Many centers were not prepared for the large demand and this stressed the resources of several centers including at the National Center for Atmospheric Research. During Phase 5, we missed several deadlines and we struggled to get the data out to the community for analysis. In preparation for the current generation, Phase 6, we examined the weaknesses in our workflow and addressed the performance issues with new software tools. Through this investment, we were able to publish approximately six times the amount of data to the community compared to the volumes we produced in the previous generation and we were able to accomplish this within one-third of the time, providing an 18 times speedup. This paper discusses the improvements we have made to accomplish this success for Phase 6 and further improvements we hope to make for the next generation.

scholarly journals A new end-to-end workflow for the Community Earth System Model (version 2.0) for the Coupled Model Intercomparison Project Phase 6 (CMIP6)

2020 ◽  
Vol 13 (11) ◽  
pp. 5567-5581
Author(s):  
Sheri Mickelson ◽  
Alice Bertini ◽  
Gary Strand ◽  
Kevin Paul ◽  
Eric Nienhouse ◽  
...  
Keyword(s):  
Coupled Model ◽  
Model Intercomparison ◽  
Phase 3 ◽  
Previous Generation ◽  
Data Volume ◽  
Community Earth System Model ◽  
Intercomparison Project ◽  
Version 2.0 ◽  
New Generation ◽  
Compressed Data

Abstract. The complexity of each Coupled Model Intercomparison Project grows with every new generation. The Phase 5 effort saw a dramatic increase in the number of experiments that were performed and the number of variables that were requested compared to its previous generation, Phase 3. The large increase in data volume stressed the resources of several centers including at the National Center for Atmospheric Research. During Phase 5, we missed several deadlines and we struggled to get the data out to the community for analysis. In preparation for the current generation, Phase 6, we examined the weaknesses in our workflow and addressed the performance issues with new software tools. Through this investment, we were able to publish approximately 565 TB of compressed data to the community, with another 30 TB yet to be published. When compared to the volumes we produced in the previous generation, 165 TB of uncompressed data, we were able to provide 6 times the amount of data and we accomplish this within one-third of the time. This provided us with an approximate 18 times faster speedup. While this paper discusses the improvements we have made to our own workflow for the Coupled Model Intercomparison Project Phase 6 (CMIP6), we hope to encourage other centers to evaluate and invest in their own workflows in order to be successful in these types of modeling campaigns.

scholarly journals Atmospheric and Surface Contributions to Planetary Albedo

2011 ◽  
Vol 24 (16) ◽  
pp. 4402-4418 ◽  
Author(s):  
Aaron Donohoe ◽  
David S. Battisti
Keyword(s):  
Surface Albedo ◽  
Coupled Model ◽  
Small Contribution ◽  
Model Intercomparison ◽  
Radiation Model ◽  
Phase 3 ◽  
Surface Reflection ◽  
Global Average ◽  
Intercomparison Project ◽  
Planetary Albedo

Abstract The planetary albedo is partitioned into a component due to atmospheric reflection and a component due to surface reflection by using shortwave fluxes at the surface and top of the atmosphere in conjunction with a simple radiation model. The vast majority of the observed global average planetary albedo (88%) is due to atmospheric reflection. Surface reflection makes a relatively small contribution to planetary albedo because the atmosphere attenuates the surface contribution to planetary albedo by a factor of approximately 3. The global average planetary albedo in the ensemble average of phase 3 of the Coupled Model Intercomparison Project (CMIP3) preindustrial simulations is also primarily (87%) due to atmospheric albedo. The intermodel spread in planetary albedo is relatively large and is found to be predominantly a consequence of intermodel differences in atmospheric albedo, with surface processes playing a much smaller role despite significant intermodel differences in surface albedo. The CMIP3 models show a decrease in planetary albedo under a doubling of carbon dioxide—also primarily due to changes in atmospheric reflection (which explains more than 90% of the intermodel spread). All models show a decrease in planetary albedo due to the lowered surface albedo associated with a contraction of the cryosphere in a warmer world, but this effect is small compared to the spread in planetary albedo due to model differences in the change in clouds.

scholarly journals Description of the MIROC-ES2L Earth system model and evaluation of its climate–biogeochemical processes and feedbacks

2019 ◽  
Author(s):  
Tomohiro Hajima ◽  
Michio Watanabe ◽  
Akitomo Yamamoto ◽  
Hiroaki Tatebe ◽  
Maki A. Noguchi ◽  
...  
Keyword(s):  
Carbon Cycle ◽  
Nitrogen Cycle ◽  
Carbon Sink ◽  
Coupled Model ◽  
System Model ◽  
Climate Response ◽  
Earth System ◽  
Model Intercomparison ◽  
Transient Climate Response ◽  
Intercomparison Project

Abstract. This study developed a new Model for Interdisciplinary Research on Climate, Earth System version2 for Long-term simulations (MIROC-ES2L) Earth system model (ESM) using a state-of-the-art climate model as the physical core. This model embeds a terrestrial biogeochemical component with explicit carbon–nitrogen interaction to account for soil nutrient control on plant growth and the land carbon sink. The model’s ocean biogeochemical component is largely updated to simulate biogeochemical cycles of carbon, nitrogen, phosphorus, iron, and oxygen such that oceanic primary productivity can be controlled by multiple nutrient limitations. The ocean nitrogen cycle is coupled with the land component via river discharge processes, and external inputs of iron from pyrogenic and lithogenic sources are considered. Comparison of a historical simulation with observation studies showed the model could reproduce reasonable historical changes in climate, the carbon cycle, and other biogeochemical variables together with reasonable spatial patterns of distribution of the present-day condition. The model demonstrated historical human perturbation of the nitrogen cycle through land use and agriculture, and it simulated the resultant impact on the terrestrial carbon cycle. Sensitivity analyses in preindustrial conditions revealed modeled ocean biogeochemistry could be changed regionally (but substantially) by nutrient inputs from the atmosphere and rivers. Through an idealized experiment of a 1 %CO2 increase scenario, we found the transient climate response (TCR) in the model is 1.5 K, i.e., approximately 70 % that of our previous model. The cumulative airborne fraction (AF) is also reduced by 15 % because of the intensified land carbon sink, resulting in an AF close to the multimodel mean of the Coupled Model Intercomparison Project Phase 5 (CMIP5) ESMs. The transient climate response to cumulative carbon emission (TCRE) is 1.3 K EgC−1, i.e., slightly smaller than the average of the CMIP5 ESMs, suggesting optimistic model performance in future climate projections. This model and the simulation results are contributing to the Coupled Model Intercomparison Project Phase 6 (CMIP6). The ESM could help further understanding of climate–biogeochemical interaction mechanisms, projections of future environmental changes, and exploration of our future options regarding sustainable development by evolving the processes of climate, biogeochemistry, and human activities in a holistic and interactive manner.

scholarly journals Global exposure to flooding from the new CMIP6 climate model projections

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yukiko Hirabayashi ◽  
Masahiro Tanoue ◽  
Orie Sasaki ◽  
Xudong Zhou ◽  
Dai Yamazaki
Keyword(s):  
Spatial Patterns ◽  
Flood Risk ◽  
Climate Models ◽  
Climate Model ◽  
Model Development ◽  
Coupled Model ◽  
Model Intercomparison ◽  
Internal Climate Variability ◽  
Intercomparison Project ◽  
New Generation

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.

scholarly journals Avaliação de Modelos do CMIP5 que Melhor Expressam a Atuação dos Vórtices Ciclônicos em Altos Níveis (VCANS) no Nordeste Brasileiro (NEB) (Evaluation of the CMIP5 Models that Express the Best Performance of Vortice in High Levels (VCANS) in Northeast...)

2015 ◽  
Vol 7 (5) ◽  
pp. 891
Author(s):  
José Ueliton Pinheiro ◽  
Josemir Araújo Neves ◽  
Rosane Rodrigues Chaves ◽  
David Mendes ◽  
Naurinete Costa Barreto
Keyword(s):  
Climate Change ◽  
Mean Square Error ◽  
Coupled Model ◽  
Mean Square ◽  
Model Intercomparison ◽  
Intergovernmental Panel ◽  
Assessment Report ◽  
Atmospheric Research ◽  
Intercomparison Project ◽  
Environmental Prediction

A pesquisa estudou a saída de modelos de mudanças climáticas que melhor expressam a atuação dos Vórtices Ciclônicos em Altos Níveis (VCANs) no Nordeste Brasileiro (NEB). Os VCANs foram quantificados pela sua ocorrência diária durante 5 anos (1995-1999), no período de outubro a março. O objeto de estudo foram 13 modelos do CMIP5/IPCC/AR5 (Coupled Model Intercomparison Project Phase 5/Intergovernmental Panel on Climate Change/Fifth Assessment Report), comparados com os resultados do NCEP/NCAR (National Centers for Environmental Prediction/National Center for Atmospheric Research), por meio de métodos estatísticos para escolha do modelo que melhor indica a presença dos VCANs no NEB. A primeira análise comparativa foi feita através das correlações de Pearson, Kendall e Spearman, Raiz quadrada do erro quadrático médio, Raiz quadrada do erro quadrático médio normalizada e os índices de Eficiência e desempenho, Nash-Sutcliffe (NSE), Kling-Gupta (KGE) e o Índice de Concordância de Willmott (d). Em seguida foram selecionados os modelos de melhor desempenho e com significância estatística para uma análise posterior de acertos e erros através dos índices: Índice de Proporção Correta (PC), Índice de Sucesso Crítico (ISC), Probabilidade de Detecção (POD), Taxa de alarme Falso (TAF) e Taxa de Tendência (VIÉS). Para os testes estatísticos aplicados na primeira avaliação realizada o modelo MIROC4h foi o que apresentou os melhores índices seguido pelo MIROC-ESM e inmCM4, respectivamente. Além destes, ainda apresentaram correlação estatística significante o MPI-ESM-LR,o MRI-CGCM3 e o CSIRO-MK3-6-0. A segunda análise também apresentou o MIROC4h com os melhores valores de PC, ISC e POD, excetuando-se o VIÉS que apresentou o segundo melhor resultado e o TAF com o pior resultado em relação aos outros 5 modelos. Dessa forma o MIROC4h apresentou-se como o mais indicado entre os modelos do CMIP5 para estudos de cenários presentes e futuros de VCANs no NEB.   A B S T R A C T The research studied the output of climate change models that best express the actions of Upper Tropospheric Cyclonic Vortices (UTCV) in high levels in the Northeast Brazil (NEB). The UTCV were quantified by a daily occurrence for 5 years (1995-1999) in the period from October to March. The object of the study were 13 models from CMIP5/IPCC/AR5 (Coupled Model Intercomparison Project Phase 5 / Intergovernmental Panel on Climate Change / Fifth Assessment Report ), compared with results from the NCEP / NCAR (National Centers for Environmental Prediction / National Center for Atmospheric Research) by means of statistical methods for choosing the model which best indicates the presence of UTCV in the NEB. The first comparative analysis was performed using the Pearson, Spearman and Kendall correlations, mean square error, normalized mean square error and efficiency and performance indices, Nash-Sutcliff (NSE), Kling-Gupta (KGE) and Index of Agreement of the Willmott (d). Then models with better performance and statistical significance for further analysis of successes and mistakes through the indices were selected: Index Proportion Correct (PC), Critical Success Index (CSI), Probability of Detection (POD), False Alarm Rate (FAR) and Trend Rate (BIAS). For the statistical analyzes used in the first test performed MIROC4h model showed the best rates followed by MIROC-ESM and inmCM4 respectively. In addition, further significant statistical correlation MPI-ESM-LR, MRI-CGCM3 and CSIRO-MK3-6-0. The second analysis also showed the MIROC4h with the best values ​​of PC, CSI and POD, except the BIAS that had the second best result and the FAR with the worst result in relation to the other five models considered in this phase. Thus the MIROC4h introduced himself as the most suitable model of the CMIP5 for studies of the present and future scenarios of UTCV in the NEB   

scholarly journals Understanding the CMIP3 Multimodel Ensemble

2011 ◽  
Vol 24 (16) ◽  
pp. 4529-4538 ◽  
Author(s):  
J. D. Annan ◽  
J. C. Hargreaves
Keyword(s):  
Coupled Model ◽  
Model Intercomparison ◽  
Ensemble Size ◽  
Multimodel Ensemble ◽  
Phase 3 ◽  
Climate Research ◽  
Intercomparison Project ◽  
The Mean ◽  
Main Factors ◽  
And Behavior

Abstract The Coupled Model Intercomparison Project phase 3 (CMIP3) multimodel ensemble has been widely utilized for climate research and prediction, but the properties and behavior of the ensemble are not yet fully understood. Here, some investigations are undertaken into various aspects of the ensemble’s behavior, in particular focusing on the performance of the multimodel mean. This study presents an explanation of this phenomenon in the context of the statistically indistinguishable paradigm and also provides a quantitative analysis of the main factors that control how likely the mean is to outperform the models in the ensemble, both individually and collectively. The analyses lend further support to the usage of the paradigm of a statistically indistinguishable ensemble and indicate that the current ensemble size is too small to adequately sample the space from which the models are drawn.

scholarly journals The Interannual Relationship between the Latitude of the Eddy-Driven Jet and the Edge of the Hadley Cell

2011 ◽  
Vol 24 (2) ◽  
pp. 563-568 ◽  
Author(s):  
Sarah M. Kang ◽  
Lorenzo M. Polvani
Keyword(s):  
Coupled Model ◽  
Austral Summer ◽  
Hadley Cell ◽  
Model Intercomparison ◽  
Phase 3 ◽  
Long Term Trends ◽  
Intercomparison Project ◽  
Highly Correlated ◽  
Universal Ratio

Abstract A strong correlation between the latitudes of the eddy-driven jet and of the Hadley cell edge, on interannual time scales, is found to exist during austral summer, in both the NCEP–NCAR reanalysis and the models participating in the Coupled Model Intercomparison Project, phase 3 (CMIP3). In addition, a universal ratio close to 1:2 characterizes the robust connection between these two latitudes on a year-to-year basis: for a 2° shift of the eddy-driven jet, the edge of the Hadley cell shifts by 1°. This 1:2 interannual ratio remains the same in response to climate change, even though the values of the two latitudes increase. The corresponding trends are also highly correlated; in the CMIP3 scenario integrations, however, no universal ratio appears to exist connecting these long-term trends. In austral winter and in the Northern Hemisphere, no strong interannual correlations are found.

scholarly journals Numerical simulations of oceanic oxygen cycling in the FAMOUS Earth-System model: FAMOUS-ES, version 1.0

2014 ◽  
Vol 7 (1) ◽  
pp. 1453-1476
Author(s):  
J. H. T. Williams ◽  
I. J. Totterdell ◽  
P. R. Halloran ◽  
P. J. Valdes
Keyword(s):  
Climate Model ◽  
Coupled Model ◽  
System Model ◽  
Temperature Structure ◽  
Model Intercomparison ◽  
Oxygen Cycle ◽  
Surface Productivity ◽  
Intercomparison Project ◽  
Oxygen Cycling ◽  
Good Agreement

Abstract. Addition and validation of an oxygen cycle to the ocean component of the FAMOUS climate model are described. Surface validation is carried out with respect to HadGEM2-ES where good agreement is found and where discrepancies are mainly attributed to disagreement in surface temperature structure between the models. The agreement between the models at depth (where observations are also used in the comparison) in the Southern Hemisphere is less encouraging than in the Northern Hemisphere. This is attributed to a combination of excessive surface productivity in FAMOUS' equatorial waters (and its concomitant effect on remineralisation at depth) and its reduced overturning circulation compared to HadGEM2-ES. For the entire Atlantic basin FAMOUS has a circulation strength of 12.7 ± 0.4 Sv compared to 15.0 ± 0.9 for HadGEM2-ES. The HadGEM2-ES data used in this paper were obtained from the online database of the fifth Coupled Model Intercomparison Project, CMIP5 (Taylor et al., 2012).

scholarly journals The Norwegian Earth System Model, NorESM2 – Evaluation of theCMIP6 DECK and historical simulations

2020 ◽  
Author(s):  
Øyvind Seland ◽  
Mats Bentsen ◽  
Lise Seland Graff ◽  
Dirk Olivié ◽  
Thomas Toniazzo ◽  
...  
Keyword(s):  
Sea Ice ◽  
Deep Convection ◽  
Coupled Model ◽  
Momentum Conservation ◽  
Earth System Model ◽  
System Model ◽  
Earth System ◽  
Model Intercomparison ◽  
Intercomparison Project ◽  
The Stability

Abstract. The second version of the fully coupled Norwegian Earth System Model (NorESM2) is presented and evaluated. NorESM2 is based on the second version of the Community Earth System Model (CESM2), but has entirely different ocean and ocean biogeochemistry models; a new module for aerosols in the atmosphere model along with aerosol-radiation-cloud interactions and changes related to the moist energy formulation, deep convection scheme and angular momentum conservation; modified albedo and air-sea turbulent flux calculations; and minor changes to land and sea ice models. We show results from low (∼2°) and medium (∼1°) atmosphere-land resolution versions of NorESM2 that have both been used to carry out simulations for the sixth phase of the Coupled Model Intercomparison Project (CMIP6). The stability of the pre-industrial climate and the sensitivity of the model to abrupt and gradual quadrupling of CO2 is assessed, along with the ability of the model to simulate the historical climate under the CMIP6 forcings. As compared to observations and reanalyses, NorESM2 represents an improvement over previous versions of NorESM in most aspects. NorESM2 is less sensitive to greenhouse gas forcing than its predecessors, with an equilibrium climate sensitivity of 2.5 K in both resolutions on a 150 year frame. We also consider the model response to future scenarios as defined by selected shared socioeconomic pathways (SSP) from the Scenario Model Intercomparison Project defined under CMIP6. Under the four scenarios SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5, the warming in the period 2090–2099 compared to 1850–1879 reaches 1.3, 2.2, 3.0, and 3.9 K in NorESM2-LM, and 1.3, 2.1, 3.1, and 3.9 K in NorESM–MM, robustly similar in both resolutions. NorESM2-LM shows a rather satisfactorily evolution of recent sea ice area. In NorESM2-LM an ice free Arctic Ocean is only avoided in the SSP1-2.6 scenario.

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