The Great Powerful Tool "atlas": Simulating the Earth and Projecting the Future

Earth simulation laboratory

"Huan" computer hardware platform "Silicon Cube" display map

Earth simulation laboratory "Huan" in 2021 will be initially completed in Beijing Huairou Science City. The Earth Simulation Laboratory "Huan" will be initially completed in 2021 in Huairou Science City, Beijing.

In 2021, EarthLab, a numerical simulation device for the Earth system, led by the Institute of Atmospheric Physics of the Chinese Academy of Sciences, will be completed. This is another major tool of China, through the supercomputer to carry out large-scale numerical calculations, can reproduce the Earth's past, simulate the Earth's present, predict the future of the Earth, so as to carry out targeted "Earth test". This big country will also play an important role in carbon neutral, climate change research - December 24, 2020, the Chinese Academy of Sciences Institute of Atmospheric Physics was established in the country's first engaged in the basic research of carbon neutral research institutions, this facility is bound to realize the peak of China's carbon, carbon and carbon and to provide scientific paths and scientific and technological support.

What is the Earth System Simulation Laboratory

The Earth System Simulation Facility, also known as the Earth Simulation Laboratory. Both the 1.5 and 2 temperature rise targets set out in the Paris Agreement were calculated based on the Earth System Simulator. To put it simply, the simulated "Earth" is put into the laboratory to see how the natural systems on the "Earth" respond to global warming caused by different carbon dioxide emissions, and ultimately determine an appropriate temperature rise target. Note that the "Earth" in question is not a real Earth, but a digitized Earth based on various physical and mathematical equations.

The gaseous air, liquid rivers, lakes, and oceans on Earth, the solid rock, ice, and snow, and the constantly evolving life forms ...... can be simply categorized into five circles: the atmosphere, hydrosphere, cryosphere, lithosphere, and biosphere. For thousands of years people have been feeling the changes in the climate in each circle and at the same time summarizing the experience of the natural world. Based on the progress of science, we have been able to summarize some of the physical laws of natural changes and express them quantitatively with mathematical equations. By further writing these mathematical equations into computer codes, we get a collection of codes corresponding to each circle, which we often refer to as patterns. For example, an atmospheric model is essentially a collection of codes for the atmospheric equations of motion, continuity equations, and thermodynamic energy equations.

Because of the complexity of the interconnectedness of everything in nature, it is not possible to encapsulate the mathematical equations of all the layers in a single code set. To simplify the problem, one first builds a model that describes the individual layers, and then organically joins the separate models together through a "coupler". The coupler is like the exchange hall of a huge factory, where material and energy are exchanged between the layers, thus coupling the atmospheric, oceanic, and terrestrial models to maximize the simulation of the evolution of nature.

After getting this digitized "Earth", inputting the observation data at a certain moment, and performing large-scale numerical calculations in a supercomputer, we will be able to deduce the changes in different layers of the Earth, thus reproducing the Earth's past, simulating the Earth's present, and predicting the Earth's future, and thus carry out a targeted "Earth experiment". "Earth experiment".

The Advantages of oneworld

We already know that the real Earth is a complex system of closely interconnected circles, and that many physical, chemical, and biological processes are contained in each circle, so that the number of circles contained in a model of the Earth's system, as well as the number of natural processes in each circle, is a very large number. Therefore, the number of layers included in an Earth system model and the completeness of describing the natural processes in each layer directly affect the realism of its simulation results.

As a reflection of the comprehensive national power, scientists from various countries are actively developing their own numerical models. For example, the ongoing Sixth International Coupled Model Intercomparison Program (CMIP6) has about 112 climate model versions from 33 institutions around the world registered to participate, which is the largest number ever. Although there are so many numerical models in the world, most of them are still climate system models, and only a few countries and regions, such as the United States, Europe, Japan, China, etc., have submitted Earth system models, including CAS-ESM2.0, which is led by the Institute of Atmospheric Physics of the Chinese Academy of Sciences (IAPC). It is worth mentioning that CAS-ESM is exactly the Earth Modeling Laboratory (EML).

"Huan" is located in Huairou Science City, Beijing, and is a specialized Earth system numerical simulation device with the core of the Earth system numerical simulation software for each circle, compatible with hardware and software, and the scale and comprehensive technical level of the world's forefront. "The construction content of Huan includes not only the main Earth system model numerical simulation system, but also regional high-precision (spatial resolution of 1-3 kilometers) environmental simulation system, super simulation support and management system, support database and data assimilation and visualization system, high-performance computation system for geoscience, as well as ancillary civil engineering and construction facilities. facilities. After the completion of the "oneworld" can provide a new paradigm for China's earth system science research.

As a rising star in global Earth system simulation devices, Huan adopts a numerical simulation software system with independent intellectual property rights in China, and has a complete, self-contained, and rigorous set of dynamical, physical, chemical, and ecological processes, with a resolution that reaches the world's advanced level. And in the multi-circle coupling, the interaction between each circle is fully considered. In the near future, Huan will further couple space weather, continental glaciers and solid Earth modules (such as the movement of the Earth's plates and their triggered topographic changes, earthquakes, volcanic eruptions, etc.), and the Earth system simulation will be extended to the adjacent space and the solid Earth field. Earth system simulations will be extended to near-space and solid Earth domains.

In addition to software support, all experiments will be on paper if they are not matched by appropriate computer hardware. The global-scale simulation experiment is a supercomputing project with a wide time scale, and the domestic chip adopted by "Huan" provides super power arithmetic support for the ultra-complex earth system model. The "earth science-oriented high-performance computer system" specially developed for Huan has a peak computational value of not less than 15 PFlops, and its computational power in one minute is equivalent to that of 7.2 billion people around the world using a calculator at the same time for four years of uninterrupted computation. The whole system*** has more than 3,000 water-cooled computing nodes, which are connected to each other by HDR InfiniBand high-speed network with a bandwidth of up to 100 Gbps. In addition, the database of "Silicon Cube" has a storage space of 80 petabytes (PB), which can hold the data of about 13 national libraries, and is used to store the data of each circle and simulation data. The Silicon Cube database has 80 petabytes of storage space, which could hold the data of about 13 national libraries, and is used to store observation and simulation data for each layer.

Where is the Great National Instrument

Under the "carbon neutral" route, we will vigorously develop new energy sources and various energy-saving and emission reduction technologies to reduce carbon emissions, and at the same time promote carbon sequestration through afforestation, carbon capture and storage, and other "carbon sequestration" pathways. At the same time, through afforestation, carbon capture and sequestration and other "carbon sequestration" pathways, we will promote the absorption of greenhouse gases in the atmosphere, and ultimately make CO2 emissions equal to the amount absorbed, i.e., to achieve "net-zero" carbon emissions.

Greenhouse gas accounting and future warming predictions require simulations of Earth system models that encompass the full range of layers, and this is where we excel. "Huan is able to consider all components of the earth system more comprehensively, especially the simulation related to the earth's ecosystems and biogeochemical processes and their interactions with the climate system, based on which the "ecology - temperature - carbon dioxide concentration - carbon emissions" is established.

In addition, in the context of global warming, there has been an increase in the number of reports of extreme weather events and their impacts on human life over the past three decades, including strong typhoons, high temperatures, heavy rainfall, droughts, and cold snaps. The spatial scales of such extreme weather events are in the order of a few kilometers and the time scales are in the order of a few hours. Capturing these weather processes accurately requires an increase in the spatial resolution of the model, but it also means that it must carry a concomitant increase in the amount of computation. The completion of oneworld, equipped with high-performance computer hardware, has made it possible to accurately visualize extreme weather and climate events. Utilizing a more refined and complete Earth system model, "Huan" is able to capture more comprehensive prediction signals to improve China's disaster prevention and early warning level, enhance disaster prevention and mitigation capabilities.

As China's urbanization progresses, a variety of pollution problems arise. The problem of air pollution involves complex emission processes in the Earth system, including global and regional transport processes and urban-scale dynamics, which poses a major challenge to air pollution modeling research. Reasonable and complete simulation and reproduction of these processes is a key prerequisite for the study of air pollution and air pollution control. "Huan has a regional high-precision air pollution model subsystem that can simulate the emission, diffusion, and chemical transformation of chemical components in the atmosphere. In addition, Huan has the ability to simulate heavy metals, coupled source identification and tracking technology, which can do a good job of pollutant "traceability" analysis, thus improving the level of air pollution prediction, so that "Beautiful China "The road to ecological civilization is steady and far-reaching.

In short, the birth of "oneworld" will significantly enhance the overall innovation capacity of China's geosciences, and play an important role in China's solution to the major scientific issues of disaster prevention and mitigation, environmental governance, sustainable development and ecological security.

Looking around the world, the United States, Japan, Europe and other developed countries have built a combination of hardware and software geared to the Earth system of specialized simulation devices. For example, the U.S. National Center for Atmospheric Research (NCAR), with its long time world-leading numerical simulation device, has developed an excellent performance of the Earth system model, so these countries led the Intergovernmental Panel on Climate Change (IPCC) climate change prediction experiment design and the writing of assessment reports.

Change is happening and the future is here. The introduction of Huan, the most important tool of our country, will enable us to stop being passive in Earth modeling science, especially in the academic field of global climate change, and we will be able to have more say in dealing with global climate change issues!

(By Chen Kexin and Zhao Yin, both PhDs from the Institute of Atmospheric Physics, Chinese Academy of Sciences; images courtesy of the institute)