Effects of strongly eddying oceans on multidecadal climate variability in the Community Earth System Model

Abstract. Climate variability on multidecadal time scales appears to be organized in pronounced patterns with clear expressions in sea surface temperature, such as the Atlantic Multidecadal Variability and the Pacific Decadal Oscillation. These patterns are now well studied both in observations and global climate models and are important in the attribution of climate change. Results from CMIP5 models have indicated large biases in these patterns with consequences for ocean heat storage variability and eventually the global mean surface temperature. In this paper, we use two multi-century Community Earth System Model simulations at coarse (1°) and fine (0.1°) ocean model horizontal grid spacing to study the effects of the representation of mesoscale ocean flows on major patterns of multidecadal variability. We find that resolving mesoscale ocean flows both improves the characteristics of the modes of variability with respect to observations and increases the amplitude of the heat content variability in the individual ocean basins. The effect on the global mean surface temperature is relatively minor.

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Effects of strongly eddying oceans on multidecadal climate variability in the Community Earth System Model

Ocean Science ◽

10.5194/os-17-1251-2021 ◽

2021 ◽

Vol 17 (5) ◽

pp. 1251-1271

Author(s):

André Jüling ◽

Anna von der Heydt ◽

Henk A. Dijkstra

Keyword(s):

Climate Variability ◽

Surface Temperature ◽

Sea Surface ◽

System Model ◽

Earth System ◽

Multidecadal Variability ◽

Global Mean Surface Temperature ◽

Ocean Flows ◽

Community Earth System Model ◽

Global Mean

Abstract. Climate variability on multidecadal timescales appears to be organized in pronounced patterns with clear expressions in sea surface temperature, such as the Atlantic Multidecadal Variability and the Pacific Decadal Oscillation. These patterns are now well studied both in observations and global climate models and are important in the attribution of climate change. Results from CMIP5 models have indicated large biases in these patterns with consequences for ocean heat storage variability and the global mean surface temperature. In this paper, we use two multi-century Community Earth System Model simulations at coarse (1∘) and fine (0.1∘) ocean model horizontal grid spacing to study the effects of the representation of mesoscale ocean flows on major patterns of multidecadal variability. We find that resolving mesoscale ocean flows both improves the characteristics of the modes of variability with respect to observations and increases the amplitude of the heat content variability in the individual ocean basins. In the strongly eddying model, multidecadal variability increases compared to sub-decadal variability. This shift of spectral power is seen in sea surface temperature indices, basin-scale surface heat fluxes, and the global mean surface temperature. This implies that the current CMIP6 model generation, which predominantly does not resolve the ocean mesoscale, may systematically underestimate multidecadal variability.

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Effects of mesoscale ocean flows on multidecadal climate variability

10.5194/egusphere-egu2020-20598 ◽

2020 ◽

Cited By ~ 1

Author(s):

André Jüling ◽

Anna von der Heydt ◽

Henk Dijkstra

Keyword(s):

Climate Variability ◽

Surface Temperature ◽

Climate Models ◽

Heat Content ◽

Global Climate Models ◽

Cmip5 Models ◽

Multidecadal Variability ◽

Global Mean Surface Temperature ◽

Ocean Flows ◽

Global Mean

<div> <div>Climate variability on decadal to multidecadal time scales appears to be organized in pronounced patterns with clear expressions in sea surface temperature, such as the Pacific Multidecadal Variability and the Atlantic Multidecadal Variability. These patterns are now well studied both in observations and in global climate models and are important in the attribution of climate change. Results in CMIP5 models have indicated large biases in these patterns with consequences for ocean heat storage variability and eventually the global mean surface temperature.</div> <div>We use two multi-century Community Earth System Model simulations at coarse (1&#176;) and fine (0.1&#176;) ocean model horizontal grid spacing and study the effect of the representation of mesoscale ocean flows on major patterns of multidecadal variability. We find that resolving mesoscale ocean flows both improves the characteristics of the modes of variability with respect to observations and increases the amplitude of the heat content variability in the individual ocean basins. However, the effect on the global mean surface temperature is relatively minor.</div> </div>

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A consistent prescription of stratospheric aerosol for both radiation and chemistry in the Community Earth System Model (CESM1)

Geoscientific Model Development ◽

10.5194/gmd-9-2459-2016 ◽

2016 ◽

Vol 9 (7) ◽

pp. 2459-2470 ◽

Cited By ~ 11

Author(s):

Ryan Reynolds Neely III ◽

Andrew J. Conley ◽

Francis Vitt ◽

Jean-François Lamarque

Keyword(s):

Surface Temperature ◽

Temperature Response ◽

Stratospheric Aerosol ◽

Earth System Model ◽

System Model ◽

Earth System ◽

Climate System Model ◽

Pinatubo Eruption ◽

Community Earth System Model ◽

Global Mean

Abstract. Here we describe an updated parameterization for prescribing stratospheric aerosol in the National Center for Atmospheric Research (NCAR) Community Earth System Model (CESM1). The need for a new parameterization is motivated by the poor response of the CESM1 (formerly referred to as the Community Climate System Model, version 4, CCSM4) simulations contributed to the Coupled Model Intercomparison Project 5 (CMIP5) to colossal volcanic perturbations to the stratospheric aerosol layer (such as the 1991 Pinatubo eruption or the 1883 Krakatau eruption) in comparison to observations. In particular, the scheme used in the CMIP5 simulations by CESM1 simulated a global mean surface temperature decrease that was inconsistent with the GISS Surface Temperature Analysis (GISTEMP), NOAA's National Climatic Data Center, and the Hadley Centre of the UK Met Office (HADCRUT4). The new parameterization takes advantage of recent improvements in historical stratospheric aerosol databases to allow for variations in both the mass loading and size of the prescribed aerosol. An ensemble of simulations utilizing the old and new schemes shows CESM1's improved response to the 1991 Pinatubo eruption. Most significantly, the new scheme more accurately simulates the temperature response of the stratosphere due to local aerosol heating. Results also indicate that the new scheme decreases the global mean temperature response to the 1991 Pinatubo eruption by half of the observed temperature change, and modelled climate variability precludes statements as to the significance of this change.

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Tropical climate variability in the Community Earth System Model: Data Assimilation Research Testbed

Climate Dynamics ◽

10.1007/s00382-019-05030-6 ◽

2019 ◽

Vol 54 (1-2) ◽

pp. 793-806 ◽

Cited By ~ 1

Author(s):

Jonathan Eliashiv ◽

Aneesh C. Subramanian ◽

Arthur J. Miller

Keyword(s):

Data Assimilation ◽

Climate Variability ◽

Tropical Climate ◽

Earth System Model ◽

The Other ◽

System Model ◽

Earth System ◽

Ocean Atmosphere ◽

Community Earth System Model ◽

Free Running

AbstractA new prototype coupled ocean–atmosphere Ensemble Kalman Filter reanalysis product, the Community Earth System Model using the Data Assimilation Research Testbed (CESM-DART), is studied by comparing its tropical climate variability to other reanalysis products, available observations, and a free-running version of the model. The results reveal that CESM-DART produces fields that are comparable in overall performance with those of four other uncoupled and coupled reanalyses. The clearest signature of differences in CESM-DART is in the analysis of the Madden–Julian Oscillation (MJO) and other tropical atmospheric waves. MJO energy is enhanced over the free-running CESM as well as compared to the other products, suggesting the importance of the surface flux coupling at the ocean–atmosphere interface in organizing convective activity. In addition, high-frequency Kelvin waves in CESM-DART are reduced in amplitude compared to the free-running CESM run and the other products, again supportive of the oceanic coupling playing a role in this difference. CESM-DART also exhibits a relatively low bias in the mean tropical precipitation field and mean sensible heat flux field. Conclusive evidence of the importance of coupling on data assimilation performance will require additional detailed direct comparisons with identically formulated, uncoupled data assimilation runs.

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The IITM Earth System Model: Transformation of a Seasonal Prediction Model to a Long-Term Climate Model

Bulletin of the American Meteorological Society ◽

10.1175/bams-d-13-00276.1 ◽

2015 ◽

Vol 96 (8) ◽

pp. 1351-1367 ◽

Cited By ~ 22

Author(s):

P. Swapna ◽

M. K. Roxy ◽

K. Aparna ◽

K. Kulkarni ◽

A. G. Prajeesh ◽

...

Keyword(s):

Prediction Model ◽

Surface Temperature ◽

Mixed Layer ◽

Climate Model ◽

Seasonal Prediction ◽

Earth System Model ◽

System Model ◽

Cold Bias ◽

Earth System ◽

Global Mean

Abstract With the goal of building an Earth system model appropriate for detection, attribution, and projection of changes in the South Asian monsoon, a state-of-the-art seasonal prediction model, namely the Climate Forecast System version 2 (CFSv2) has been adapted to a climate model suitable for extended climate simulations at the Indian Institute of Tropical Meteorology (IITM), Pune, India. While the CFSv2 model has been skillful in predicting the Indian summer monsoon (ISM) on seasonal time scales, a century-long simulation with it shows biases in the ocean mixed layer, resulting in a 1.5°C cold bias in the global mean surface air temperature, a cold bias in the sea surface temperature (SST), and a cooler-than-observed troposphere. These biases limit the utility of CFSv2 to study climate change issues. To address biases, and to develop an Indian Earth System Model (IITM ESMv1), the ocean component in CFSv2 was replaced at IITM with an improved version, having better physics and interactive ocean biogeochemistry. A 100-yr simulation with the new coupled model (with biogeochemistry switched off) shows substantial improvements, particularly in global mean surface temperature, tropical SST, and mixed layer depth. The model demonstrates fidelity in capturing the dominant modes of climate variability such as the ENSO and Pacific decadal oscillation. The ENSO–ISM teleconnections and the seasonal leads and lags are also well simulated. The model, a successful result of Indo–U.S. collaboration, will contribute to the IPCC’s Sixth Assessment Report (AR6) simulations, a first for India.

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Community Earth System Model Simulations Reveal the Relative Importance of Afforestation and Forest Management to Surface Temperature in Eastern North America

Forests ◽

10.3390/f8120499 ◽

2017 ◽

Vol 8 (12) ◽

pp. 499 ◽

Cited By ~ 3

Author(s):

◽

Keyword(s):

Forest Management ◽

North America ◽

Surface Temperature ◽

Earth System Model ◽

System Model ◽

Eastern North America ◽

Relative Importance ◽

Earth System ◽

Model Simulations ◽

Community Earth System Model

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The NUIST Earth System Model (NESM) version 3: Description and preliminary evaluation

10.5194/gmd-2017-206 ◽

2017 ◽

Author(s):

Jian Cao ◽

Bin Wang ◽

Young-Min Yang ◽

Libin Ma ◽

Juan Li ◽

...

Keyword(s):

Climate Variability ◽

Surface Temperature ◽

Air Temperature ◽

Climate Sensitivity ◽

Land Surface ◽

Surface Air Temperature ◽

Sea Surface ◽

System Model ◽

Earth System ◽

Global Mean

Abstract. The Nanjing University of Information Science and Technology Earth System Model version 3 (NESM v3) has been developed, aiming to provide a numerical modeling platform for cross-disciplinary earth system studies, project future Earth's climate and environment changes, as well conduct subseasonal-to-seasonal prediction. While the previous model version NESM v1 simulates well the internal modes of climate variability, it has no vegetation dynamics and suffers considerable radiative energy imbalance at the top of the atmosphere and surface, resulting in large biases in the global mean surface air temperature, which limit its utility to simulate past and project future climate changes. The NESM v3 upgraded the atmospheric and land surface model components and improved physical parameterization and conservation of coupling variables. Here we describe the new version's basic features and how the major improvements were made. We demonstrate the v3 model's fidelity and suitability to address the global climate variability and change issues. The 500-year PI experiment shows negligible trends in the net heat flux at the top of atmosphere and the Earth surface. Consistently, the simulated global mean surface air temperature, land surface temperature and sea surface temperature (SST) are all in a quasi-equilibrium state. The conservation of global water is demonstrated by the stable evolution of the global mean precipitation, sea surface salinity (SSS) and sea water salinity. The sea ice extents (SIEs), as a major indication of high latitude climate, also maintain a balanced state. The simulated spatial patterns of the mean outgoing longwave radiation, SST, precipitation, SSS fields are realistic, but the model suffers from a cold bias in the North Atlantic, a warm bias in the Southern Ocean and associated deficient Antarctic sea ice area, as well as a delicate sign of the double ITCZ syndrome. The estimate radiative forcing of quadrupling carbon dioxide is about 7.24 W m-2, yielding a climate sensitivity feedback parameter of −0.98 W m-2 K-1, and the equilibrium climate sensitivity is 3.69 K. The transient climate response from the 1 pct/year increasing CO2 experiment is 2.16 K. The model's performance on internal modes and responses to external forcing during the historical period will be documented in an accompanying paper.

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The NUIST Earth System Model (NESM) version 3: description and preliminary evaluation

Geoscientific Model Development ◽

10.5194/gmd-11-2975-2018 ◽

2018 ◽

Vol 11 (7) ◽

pp. 2975-2993 ◽

Cited By ~ 40

Author(s):

Jian Cao ◽

Bin Wang ◽

Young-Min Yang ◽

Libin Ma ◽

Juan Li ◽

...

Keyword(s):

Climate Variability ◽

Surface Temperature ◽

Air Temperature ◽

Climate Sensitivity ◽

Land Surface ◽

Surface Air Temperature ◽

Sea Surface ◽

System Model ◽

Earth System ◽

Global Mean

Abstract. The Nanjing University of Information Science and Technology Earth System Model version 3 (NESM v3) has been developed, aiming to provide a numerical modeling platform for cross-disciplinary Earth system studies, project future Earth climate and environment changes, and conduct subseasonal-to-seasonal prediction. While the previous model version NESM v1 simulates the internal modes of climate variability well, it has no vegetation dynamics and suffers considerable radiative energy imbalance at the top of the atmosphere and surface, resulting in large biases in the global mean surface air temperature, which limits its utility to simulate past and project future climate changes. The NESM v3 has upgraded atmospheric and land surface model components and improved physical parameterization and conservation of coupling variables. Here we describe the new version's basic features and how the major improvements were made. We demonstrate the v3 model's fidelity and suitability to address global climate variability and change issues. The 500-year preindustrial (PI) experiment shows negligible trends in the net heat flux at the top of atmosphere and the Earth surface. Consistently, the simulated global mean surface air temperature, land surface temperature, and sea surface temperature (SST) are all in a quasi-equilibrium state. The conservation of global water is demonstrated by the stable evolution of the global mean precipitation, sea surface salinity (SSS), and sea water salinity. The sea ice extents (SIEs), as a major indication of high-latitude climate, also maintain a balanced state. The simulated spatial patterns of the energy states, SST, precipitation, and SSS fields are realistic, but the model suffers from a cold bias in the North Atlantic, a warm bias in the Southern Ocean, and associated deficient Antarctic sea ice area, as well as a delicate sign of the double ITCZ syndrome. The estimated radiative forcing of quadrupling carbon dioxide is about 7.24 W m−2, yielding a climate sensitivity feedback parameter of −0.98 W m−2 K−1, and the equilibrium climate sensitivity is 3.69 K. The transient climate response from the 1 % yr−1 CO2 (1pctCO2) increase experiment is 2.16 K. The model's performance on internal modes and responses to external forcing during the historical period will be documented in an accompanying paper.

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Climate Variability and Change since 850 CE: An Ensemble Approach with the Community Earth System Model

Bulletin of the American Meteorological Society ◽

10.1175/bams-d-14-00233.1 ◽

2016 ◽

Vol 97 (5) ◽

pp. 735-754 ◽

Cited By ~ 187

Author(s):

Bette L. Otto-Bliesner ◽

Esther C. Brady ◽

John Fasullo ◽

Alexandra Jahn ◽

Laura Landrum ◽

...

Keyword(s):

Climate Variability ◽

Ice Cores ◽

Volcanic Eruptions ◽

Internal Variability ◽

Earth System Model ◽

System Model ◽

Earth System ◽

The Past ◽

Community Earth System Model ◽

Past Millennium

Abstract The climate of the past millennium provides a baseline for understanding the background of natural climate variability upon which current anthropogenic changes are superimposed. As this period also contains high data density from proxy sources (e.g., ice cores, stalagmites, corals, tree rings, and sediments), it provides a unique opportunity for understanding both global and regional-scale climate responses to natural forcing. Toward that end, an ensemble of simulations with the Community Earth System Model (CESM) for the period 850–2005 (the CESM Last Millennium Ensemble, or CESM-LME) is now available to the community. This ensemble includes simulations forced with the transient evolution of solar intensity, volcanic emissions, greenhouse gases, aerosols, land-use conditions, and orbital parameters, both together and individually. The CESM-LME thus allows for evaluation of the relative contributions of external forcing and internal variability to changes evident in the paleoclimate data record, as well as providing a longer-term perspective for understanding events in the modern instrumental period. It also constitutes a dynamically consistent framework within which to diagnose mechanisms of regional variability. Results demonstrate an important influence of internal variability on regional responses of the climate system during the past millennium. All the forcings, particularly large volcanic eruptions, are found to be regionally influential during the preindustrial period, while anthropogenic greenhouse gas and aerosol changes dominate the forced variability of the mid- to late twentieth century.

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