Mathematical modeling and numerical simulation are important means to study the evolution mechanism of the Earth shells and predict their future changes. With the better understanding of it, the physical and chemical processes considered by the model tends to be more remine. To face the severe challenges caused by climate change, President Xi Jinping proposed on the 75th session of the United Nations General Assembly in September 2020 that China's carbon dioxide emissions should peak by 2030 and strive to achieve carbon neutrality by 2060. In order to provide scientific support for government decision-making, the traditional climate system model can not meet the requirement because it did not consider ecological, terrestrial marine biogeochemical and other physical and chemical processes which are closely related to the carbon cycle. Therefore, it is an urgent need to develop aerosols, atmospheric chemistry, vegetation dynamics, biogeochemical and carbon nitrogen cycle processes, including the development of the Earth system model.
Recently, Journal of Advances in Modeling Earth Systems (JAMES) published an article entitled "Description and Climate Performance of CAS-ESM Version 2". "CAS-ESM is the first independently developed Earth system model in China, consisting of 8 component models: atmospheric circulation mode IAP AGCM5.0.Ocean circulation mode COMLI2. Land-based process model COLM (including terrestrial biogeochemical process), " said He Zhang, first author of the article, which is the second version of the Earth system model developed by the Chinese Academy of Sciences. Sea ice model CICE4. Aerosol and atmospheric chemistry model IAP AACM, vegetation dynamics model IAP DGVM, and marine biogeochemical model IAP OBGCM. ”
CAS-ESM2.0 contains the global carbon-nitrogen cycle, biogeochemicals of land and sea, fire interference, dynamic vegetation changes, and can predict future CO2 concentrations. In addition to global simulations, CAS-ESM2.0 has completed a two-way coupling of regional mode WWRF with global models for fine-tuning of critical areas.
Till now, CAS-ESM2.0 has completed the climate diagnosis, assessment and description test (DECK test), historical climate simulation test (Historical test), future scenario estimation test ScenarioMIP, ocean model comparison plan test OMIP, flux abnormal forcing comparison plan test FAFMIP, etc. The simulation results of the model show that CAS-ESM2.0 can reasonably simulate the meridian heat transfer of the atmosphere and ocean, the vertical distribution of the Atlantic erotiocycial flipped circulation (AMOC), etc. In addition, the model can also simulate the climate distribution characteristics of ocean temperature, salinity, sea ice intensity, etc. The changes of ocean thermal content, dynamic sea surface height and so on simulated in the FAFMIP test are comparable to the international mainstream model.
In addition to JAMES articles, data description articles on CAS-ESM2.0 simulation trials have been published in the CMIP6 special issue of Advances In Advanced In Sciences.
"The publication of the paper is just a good start, and we still have a lot of work to do in the future. CMIP6 has set up a total of 23 sub-planned trials, and we will continue to complete other trials to share the simulation results with scientists around the world. In addition, we need to further improve the simulation performance of the model, so that CAS-ESM2.0 for the 'beautiful China', 'Belt and Road', carbon neutral and other national strategies to provide strong scientific and technological support. He Zhang said.
Zhang, H., Zhang, M., Jin, J., Fei, K., Ji, D., Wu, C., et al., 2020: Description and climate simulation performance of CAS-ESM version 2. Journal of Advances in Modeling Earth Systems, 12.e 2020MS002210., https://doi.org/10.1029/2020MS002210.
Dong, X., Jin, J., Liu, H., Zhang, H., Zhang, M., Lin, P., et al., 2020: CAS-ESM2.0 model datasets for the CMIP6 Ocean Model Intercomparison Project Phase 1 (OMIP1). Adv. Atmos. Sci., https://doi.org/10.1007/s00376-020-0150-3.
Jin, J., Zhang, H., Dong, X., Liu H., Zhang M., Gao, X., et al., 2020: CAS-ESM2.0 Model Datasets for CMIP6 Flux-Anomaly-Forced Model Intercomparison Project (FAFMIP). Adv. Atmos. Sci., https://doi.org/10.1007/s00376-020-0188-2. http://www.iapjournals.ac.cn/aas/en/article/doi/10.1007/s00376-020-0188-2
