HighResMIP climate simulations with NICAM and beyond on supercomputer Fugaku

2021 ◽  
Author(s):  
Chihiro Kodama ◽  
Yohei Yamada ◽  
Tomoki Ohno ◽  
Tatsuya Seiki ◽  
Hisashi Yashiro ◽  
...  
Keyword(s):  
Cloud Amount ◽  
Cloud Microphysics ◽  
Shortwave Radiation ◽  
The Arctic ◽  
Climate Simulation ◽  
Surface Model ◽  
Model Intercomparison ◽  
Anthropogenic Aerosols ◽  
Climate Simulations ◽  
Intercomparison Project

<p>The Non-hydrostatic ICosahedral Atmospheric Model (NICAM), a global model with an icosahedral grid system, has been under development for nearly two decades. Here, we present its recent updates for the Coupled Model Intercomparison Project Phase 6, High Resolution Model Intercomparison Project (HighResMIP) and their impact on the simulated mean states using 56-14km mesh model. Major updates include updates of the cloud microphysics scheme and land surface model, introduction of natural and anthropogenic aerosols and a subgrid-scale orographic gravity wave drag scheme, and improvement of the coupling between the cloud microphysics and the radiation schemes. A short-term sensitivity experiments demonstrate improvements in the ice water content, high cloud amount, surface air temperature over the Arctic region, location and strength of zonal mean subtropical jet, and shortwave radiation over Africa and South Asia. The decadal climate simulations further reveal an improvement in the genesis and structure of the tropical cyclones compared with those with the previous model. Finally, we will address outlook toward the cloud-resolving climate simulation based on a fresh benchmark result on supercomputer Fugaku, a flagship supercomputer in Japan.</p>

scholarly journals The Nonhydrostatic ICosahedral Atmospheric Model for CMIP6 HighResMIP simulations (NICAM16-S): experimental design, model description, and impacts of model updates

2021 ◽  
Vol 14 (2) ◽  
pp. 795-820
Author(s):  
Chihiro Kodama ◽  
Tomoki Ohno ◽  
Tatsuya Seiki ◽  
Hisashi Yashiro ◽  
Akira T. Noda ◽  
...  
Keyword(s):  
Cloud Amount ◽  
Atmospheric Model ◽  
Cloud Microphysics ◽  
Shortwave Radiation ◽  
The Arctic ◽  
Model Description ◽  
Surface Model ◽  
Model Intercomparison ◽  
Anthropogenic Aerosols ◽  
Intercomparison Project

Abstract. The Nonhydrostatic ICosahedral Atmospheric Model (NICAM), a global model with an icosahedral grid system, has been under development for nearly two decades. This paper describes NICAM16-S, the latest stable version of NICAM (NICAM.16), modified for the Coupled Model Intercomparison Project Phase 6, High Resolution Model Intercomparison Project (HighResMIP). Major updates of NICAM.12, a previous version used for climate simulations, included updates of the cloud microphysics scheme and land surface model, introduction of natural and anthropogenic aerosols and a subgrid-scale orographic gravity wave drag scheme, and improvement of the coupling between the cloud microphysics and the radiation schemes. External forcings were updated to follow the protocol of the HighResMIP. A series of short-term sensitivity experiments were performed to determine and understand the impacts of these various model updates on the simulated mean states. The NICAM16-S simulations demonstrated improvements in the ice water content, high cloud amount, surface air temperature over the Arctic region, location and strength of zonal mean subtropical jet, and shortwave radiation over Africa and South Asia. Some long-standing biases, such as the double intertropical convergence zone and smaller low cloud amount, still exist or are even worse in some cases, suggesting further necessity for understanding their mechanisms, upgrading schemes and parameter settings, and enhancing horizontal and vertical resolutions.

scholarly journals The non-hydrostatic global atmospheric model for CMIP6 HighResMIP simulations (NICAM16-S): Experimental design, model description, and sensitivity experiments

2020 ◽  
Author(s):  
Chihiro Kodama ◽  
Tomoki Ohno ◽  
Tatsuya Seiki ◽  
Hisashi Yashiro ◽  
Akita T. Noda ◽  
...  
Keyword(s):  
Atmospheric Model ◽  
Cloud Microphysics ◽  
Shortwave Radiation ◽  
The Arctic ◽  
Model Description ◽  
Model Intercomparison ◽  
Anthropogenic Aerosols ◽  
Sensitivity Experiments ◽  
Global Atmospheric Model ◽  
Intercomparison Project

Abstract. NICAM, a nonhydrostatic global atmospheric model with an icosahedral grid system, has been developed for nearly two decades. This paper describes NICAM16-S, the latest stable version of NICAM (NICAM.16) modified for Coupled Model Intercomparison Project Phase 6 (CMIP6). Major updates from NICAM.12, a previous version used for climate simulations, include updates of a cloud microphysics scheme and a land model, an introduction of natural and anthropogenic aerosols and a subgrid-scale orographic gravity wave drag, and improvement of coupling between cloud microphysics and radiation schemes. External forcings were updated to follow a protocol of CMIP6 High Resolution Model Intercomparison Project (HighResMIP). A series of short-term sensitivity experiments were performed to check and understand impacts of the model updates on the simulated mean states. Improvements in the ice water content, the high cloud amounts, the surface air temperature over the Arctic region, the location and the strength of zonal mean subtropical jet, and shortwave radiation over the Africa and the South Asia were found in the NICAM16-S simulations. Some long-standing biases such as the double intertropical convergence zone and smaller low cloud amounts still exist or even worsen in some cases, suggesting further necessity for understanding their mechanisms and upgrading schemes and/or their parameter settings as well as for enhancing horizontal and vertical resolutions.

scholarly journals Machine dependence and reproducibility for coupled climate simulations: the HadGEM3-GC3.1 CMIP Preindustrial simulation

2020 ◽  
Vol 13 (1) ◽  
pp. 139-154 ◽  
Author(s):  
Maria-Vittoria Guarino ◽  
Louise C. Sime ◽  
David Schroeder ◽  
Grenville M. S. Lister ◽  
Rosalyn Hatcher
Keyword(s):  
Southern Oscillation ◽  
Coupled Model ◽  
Climate Simulation ◽  
Climate Projections ◽  
Model Intercomparison ◽  
Sea Ice Concentration ◽  
Mip Model ◽  
Climate Simulations ◽  
Intercomparison Project ◽  
The Impact

Abstract. When the same weather or climate simulation is run on different high-performance computing (HPC) platforms, model outputs may not be identical for a given initial condition. While the role of HPC platforms in delivering better climate projections is to some extent discussed in the literature, attention is mainly focused on scalability and performance rather than on the impact of machine-dependent processes on the numerical solution. Here we investigate the behaviour of the Preindustrial (PI) simulation prepared by the UK Met Office for the forthcoming CMIP6 (Coupled Model Intercomparison Project Phase 6) under different computing environments. Discrepancies between the means of key climate variables were analysed at different timescales, from decadal to centennial. We found that for the two simulations to be statistically indistinguishable, a 200-year averaging period must be used for the analysis of the results. Thus, constant-forcing climate simulations using the HadGEM3-GC3.1 model are reproducible on different HPC platforms provided that a sufficiently long duration of simulation is used. In regions where El Niño–Southern Oscillation (ENSO) teleconnection patterns were detected, we found large sea surface temperature and sea ice concentration differences on centennial timescales. This indicates that a 100-year constant-forcing climate simulation may not be long enough to adequately capture the internal variability of the HadGEM3-GC3.1 model, despite this being the minimum simulation length recommended by CMIP6 protocols for many MIP (Model Intercomparison Project) experiments. On the basis of our findings, we recommend a minimum simulation length of 200 years whenever possible.

scholarly journals Shortwave radiative forcing, rapid adjustment, and feedback to the surface by sulfate geoengineering: analysis of the Geoengineering Model Intercomparison Project G4 scenario

2017 ◽  
Vol 17 (5) ◽  
pp. 3339-3356 ◽  
Author(s):  
Hiroki Kashimura ◽  
Manabu Abe ◽  
Shingo Watanabe ◽  
Takashi Sekiya ◽  
Duoying Ji ◽  
...  
Keyword(s):  
Water Vapour ◽  
Radiative Forcing ◽  
Surface Albedo ◽  
Single Layer ◽  
Cloud Amount ◽  
Shortwave Radiation ◽  
Solar Radiation Management ◽  
Model Intercomparison ◽  
Intercomparison Project ◽  
Rapid Adjustment

Abstract. This study evaluates the forcing, rapid adjustment, and feedback of net shortwave radiation at the surface in the G4 experiment of the Geoengineering Model Intercomparison Project by analysing outputs from six participating models. G4 involves injection of 5 Tg yr−1 of SO2, a sulfate aerosol precursor, into the lower stratosphere from year 2020 to 2069 against a background scenario of RCP4.5. A single-layer atmospheric model for shortwave radiative transfer is used to estimate the direct forcing of solar radiation management (SRM), and rapid adjustment and feedbacks from changes in the water vapour amount, cloud amount, and surface albedo (compared with RCP4.5). The analysis shows that the globally and temporally averaged SRM forcing ranges from −3.6 to −1.6 W m−2, depending on the model. The sum of the rapid adjustments and feedback effects due to changes in the water vapour and cloud amounts increase the downwelling shortwave radiation at the surface by approximately 0.4 to 1.5 W m−2 and hence weaken the effect of SRM by around 50 %. The surface albedo changes decrease the net shortwave radiation at the surface; it is locally strong (∼ −4 W m−2) in snow and sea ice melting regions, but minor for the global average. The analyses show that the results of the G4 experiment, which simulates sulfate geoengineering, include large inter-model variability both in the direct SRM forcing and the shortwave rapid adjustment from change in the cloud amount, and imply a high uncertainty in modelled processes of sulfate aerosols and clouds.

scholarly journals Shortwave radiative forcing and feedback to the surface by sulphate geoengineering: Analysis of the Geoengineering Model Intercomparison Project G4 scenario

2016 ◽  
Author(s):  
Hiroki Kashimura ◽  
Manabu Abe ◽  
Shingo Watanabe ◽  
Takashi Sekiya ◽  
Duoying Ji ◽  
...  
Keyword(s):  
Water Vapour ◽  
Radiative Forcing ◽  
Surface Albedo ◽  
Single Layer ◽  
Cloud Amount ◽  
Shortwave Radiation ◽  
Solar Radiation Management ◽  
Model Intercomparison ◽  
Feedback Effects ◽  
Intercomparison Project

Abstract. This study evaluates the forcing and feedback of net shortwave radiation at the surface in the G4 experiment of the Geoengineering Model Intercomparison Project by analysing outputs from six participating models. G4 involves injection of 5 Tg yr−1 of SO2, a sulphate aerosol precursor, into the lower stratosphere from year 2020 to 2070 against a background scenario of RCP4.5. A single layer atmospheric model for shortwave radiative transfer is used to estimate the direct forcing of solar radiation management (SRM) and feedback effects from changes in the water vapour amount, cloud amount, and surface albedo (compared with RCP4.5). The analysis shows that the globally and temporally averaged SRM forcing ranges from −3.6 to −1.6 W m−2, depending on the model. The feedback effects due to changes in the water vapour and cloud amounts on net shortwave radiation have heating effects ranging from approximately 0.4 to 1.5 W m−2 and weaken the effect of SRM by around 50 %. The surface albedo changes have a cooling effect, which is locally strong (~ 4 W m−2) in snow and sea ice melting regions, but minor for the global average. The analyses show that the results of the G4 experiment, which simulates sulphate geoengineering, include large inter-model variability both in the direct SRM forcing and the feedback from changes in the cloud amount, and imply a high uncertainty in modelled processes of sulphate aerosols and clouds.

scholarly journals CAS FGOALS-f3-L Large-ensemble Simulations for the CMIP6 Polar Amplification Model Intercomparison Project

2021 ◽  
Author(s):  
Bian He ◽  
Xiaoqi Zhang ◽  
Anmin Duan ◽  
Qing Bao ◽  
Yimin Liu ◽  
...  
Keyword(s):  
Time Lag ◽  
The Arctic ◽  
Global Ocean ◽  
Arctic Amplification ◽  
Model Intercomparison ◽  
Large Ensemble ◽  
Sea Ice Concentration ◽  
Ensemble Simulations ◽  
Polar Amplification ◽  
Intercomparison Project

AbstractLarge-ensemble simulations of the atmosphere-only time-slice experiments for the Polar Amplification Model Intercomparison Project (PAMIP) were carried out by the model group of the Chinese Academy of Sciences (CAS) Flexible Global Ocean-Atmosphere-Land System (FGOALS-f3-L). Eight groups of experiments forced by different combinations of the sea surface temperature (SST) and sea ice concentration (SIC) for pre-industrial, present-day, and future conditions were performed and published. The time-lag method was used to generate the 100 ensemble members, with each member integrating from 1 April 2000 to 30 June 2001 and the first two months as the spin-up period. The basic model responses of the surface air temperature (SAT) and precipitation were documented. The results indicate that Arctic amplification is mainly caused by Arctic SIC forcing changes. The SAT responses to the Arctic SIC decrease alone show an obvious increase over high latitudes, which is similar to the results from the combined forcing of SST and SIC. However, the change in global precipitation is dominated by the changes in the global SST rather than SIC, partly because tropical precipitation is mainly driven by local SST changes. The uncertainty of the model responses was also investigated through the analysis of the large-ensemble members. The relative roles of SST and SIC, together with their combined influence on Arctic amplification, are also discussed. All of these model datasets will contribute to PAMIP multi-model analysis and improve the understanding of polar amplification.

scholarly journals CAS-LSM Datasets for the CMIP6 Land Surface Snow and Soil Moisture Model Intercomparison Project

2021 ◽  
Author(s):  
Binghao Jia ◽  
Longhuan Wang ◽  
Yan Wang ◽  
Ruichao Li ◽  
Xin Luo ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Land Surface ◽  
Grid Point ◽  
Global Ocean ◽  
Surface Model ◽  
Past Century ◽  
Model Intercomparison ◽  
Soil Moisture Model ◽  
Surface Snow ◽  
Intercomparison Project

AbstractThe datasets of the five Land-offline Model Intercomparison Project (LMIP) experiments using the Chinese Academy of Sciences Land Surface Model (CAS-LSM) of CAS Flexible Global-Ocean-Atmosphere-Land System Model Grid-point version 3 (CAS FGOALS-g3) are presented in this study. These experiments were forced by five global meteorological forcing datasets, which contributed to the framework of the Land Surface Snow and Soil Moisture Model Intercomparison Project (LS3MIP) of CMIP6. These datasets have been released on the Earth System Grid Federation node. In this paper, the basic descriptions of the CAS-LSM and the five LMIP experiments are shown. The performance of the soil moisture, snow, and land-atmosphere energy fluxes was preliminarily validated using satellite-based observations. Results show that their mean states, spatial patterns, and seasonal variations can be reproduced well by the five LMIP simulations. It suggests that these datasets can be used to investigate the evolutionary mechanisms of the global water and energy cycles during the past century.

scholarly journals Sensitivity of mid-Pliocene climate to changes in orbital forcing, and PlioMIP's boundary conditions

2020 ◽  
Author(s):  
Eric Samakinwa ◽  
Christian Stepanek ◽  
Gerrit Lohmann
Keyword(s):  
Boundary Conditions ◽  
The Arctic ◽  
Seasonal Temperature ◽  
Model Output ◽  
Orbital Forcing ◽  
Model Intercomparison ◽  
Model Sensitivity ◽  
Modelling Methodology ◽  
Intercomparison Project ◽  
Two Phases

Abstract. In this study, we compare results obtained from modelling the mid-Pliocene warm period using the Community Earth System Models (COSMOS, version: COSMOS-landveg r2413, 2009) with the two different modelling methodologies and sets of boundary conditions prescribed for the two phases of the Pliocene Model Intercomparison Project (PlioMIP), tagged PlioMIP1 and PlioMIP2. Boundary conditions, model forcing, and modelling methodology for the two phases of PlioMIP differ considerably in palaeogeography, in particular with regards to the state of ocean gateways, ice-masks, treatment of vegetation and topography. Further differences between model setups as suggested for PlioMIP1 and PlioMIP2 consider updates to the concentration of trace gases: atmospheric carbon dioxide (CO2), is specified as 405 and 400 parts per million by volume (ppmv) for PlioMIP1 and PlioMIP2, respectively. There are also minor differences in the concentrations of methane (CH4) and nitrous oxide (N2O) due to changes in the protocol of the Paleoclimate Model Intercomparison Project (PMIP) from phase 3 to phase 4. Employing a single model across two phases of PlioMIP enables a better understanding of the impact that the various differences in modelling methodology between PlioMIP1 and PlioMIP2 have on model output. Yet, a dedicated comparison of COSMOS model output of PlioMIP1 and PlioMIP2 is not in the curriculum of model analyses proposed in PlioMIP2. Here, we bridge the gap between our contributions to PlioMIP1 (Stepanek and Lohmann, 2012) and PlioMIP2 (Stepanek et al., 2020). We highlight some of the effects that differences in the chosen mid-Pliocene model setup (PlioMIP2 vs. PlioMIP1) have on the climate state as derived with the COSMOS, as this information will be valuable in the framework of the model-model and model-data-comparison within PlioMIP2. We evaluate the model sensitivity to improved mid-Pliocene boundary conditions using PlioMIP's core mid-Pliocene experiments for PlioMIP1 and PlioMIP2, and present further simulations where we test model sensitivity to variations in palaeogeography, orbit and concentration of CO2. Firstly, we highlight major changes in boundary conditions from PlioMIP1 to PlioMIP2 and also the challenges recorded from the initial effort. The results derived from our simulations show that COSMOS simulates a mid-Pliocene climate state that is 0.29 K colder in PlioMIP2, if compared to PlioMIP1 (17.82 °C in PlioMIP1, 17.53 °C in PlioMIP2, values based on simulated surface skin temperature). On one hand, high-latitude warming, which is supported by proxy evidence of the mid-Pliocene, is underestimated in simulations of both PlioMIP1 and PlioMIP2. On the other hand, spatial variations in surface air temperature (SAT), sea surface temperature (SST) as well as the distribution of sea ice suggest improvement of simulated SAT and SST in PlioMIP2 if employing the updated palaeogeography. Our PlioMIP2 mid-Pliocene simulation produces warmer SSTs in the Arctic and North Atlantic Ocean than derived from the respective PlioMIP1 climate state. The difference in prescribed CO2 accounts for 1.1 K of warming in the Arctic, leading to an ice-free summer in the PlioMIP1 simulation, and a quasi ice-free summer in PlioMIP2. Beyond the official set of PlioMIP2 simulations, we present further simulations and analyses that sample the phase space of potential alternative orbital forcings that have acted during the Pliocene and may have impacted on geological records. Employing orbital forcing, which differ from that proposed for PlioMIP2 (i.e. corresponding to Pre-Industrial conditions) but falls into the Mid-Pliocene time period targeted in the PlioMIP, leads to pronounced annual and seasonal temperature variations, which are not directly retrievable from the marine and terrestrial reconstruction of the time-slice.

scholarly journals 100 Years of Progress in Boundary Layer Meteorology

2019 ◽  
Vol 59 ◽  
pp. 9.1-9.85 ◽  
Author(s):  
Margaret A. LeMone ◽  
Wayne M. Angevine ◽  
Christopher S. Bretherton ◽  
Fei Chen ◽  
Jimy Dudhia ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Boundary Layers ◽  
Numerical Models ◽  
Cloud Microphysics ◽  
Lessons Learned ◽  
The Arctic ◽  
Surface Model ◽  
Near Surface ◽  
Boundary Layer Meteorology ◽  
Weather And Climate

AbstractOver the last 100 years, boundary layer meteorology grew from the subject of mostly near-surface observations to a field encompassing diverse atmospheric boundary layers (ABLs) around the world. From the start, researchers drew from an ever-expanding set of disciplines—thermodynamics, soil and plant studies, fluid dynamics and turbulence, cloud microphysics, and aerosol studies. Research expanded upward to include the entire ABL in response to the need to know how particles and trace gases dispersed, and later how to represent the ABL in numerical models of weather and climate (starting in the 1970s–80s); taking advantage of the opportunities afforded by the development of large-eddy simulations (1970s), direct numerical simulations (1990s), and a host of instruments to sample the boundary layer in situ and remotely from the surface, the air, and space. Near-surface flux-profile relationships were developed rapidly between the 1940s and 1970s, when rapid progress shifted to the fair-weather convective boundary layer (CBL), though tropical CBL studies date back to the 1940s. In the 1980s, ABL research began to include the interaction of the ABL with the surface and clouds, the first ABL parameterization schemes emerged; and land surface and ocean surface model development blossomed. Research in subsequent decades has focused on more complex ABLs, often identified by shortcomings or uncertainties in weather and climate models, including the stable boundary layer, the Arctic boundary layer, cloudy boundary layers, and ABLs over heterogeneous surfaces (including cities). The paper closes with a brief summary, some lessons learned, and a look to the future.

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