As the most important natural aerosol, sand dust not only causes serious air pollution, but also has an important impact on climate and environment. It plays an important role in the evolution of the earth system. Therefore, sand dust cycle is one of the processes that need to be considered in the earth system model.
On the basis of previous work, Wu chenglai, Lin Zhaohui, Zhang he and their collaborators, associate researchers of the earth system model research and development team of the climate and environment Excellence Center, and their collaborators have constructed a dynamic sediment discharge model based on the theory of wind erosion physics (Fig. 1), and through coupling with the land surface process model Colm, Cas-esm2.0, an earth system model of Chinese Academy of Sciences, including the interaction between dust, climate and vegetation, has been established. The sand lifting model can consider the bombardment movement of soil sand particles, the rupture of soil aggregates, and the influence of fine surface soil and vegetation characteristics on sand lifting, and has a solid foundation of wind sand physics.
The results of cas-esm2 simulation and analysis of global dust cycle based on the above coupled sediment model show that cas-esm2 can well simulate the spatial distribution of main dust sources and dust aerosols in the world, as well as the spatial distribution and magnitude range of dust deposition flux and ground dust concentration; The model can also reasonably simulate the seasonal variation characteristics of dust activities in East Asia. On this basis, the quantitative estimation of global sand and dust revenue and expenditure is given, in which the global annual total sediment discharge is about 2.518 billion tons / year (Fig. 2). In addition, compared with NCAR universal earth system model (cesm2), cas-esm2 is significantly better than cesm2 in the simulation of global dust aerosol distribution and dust aerosol optical thickness. In particular, it overcomes the systematic deviation of cesm2 from the overestimation of dust concentration in Taklimakan Desert in Northwest China (Fig. 3) and eastern North Africa, It shows that the simulation of global dust cycle by cas-esm2 has reached the international advanced level.
The above research results were published in the Journal of advances in modeling earth systems, a professional journal in the field of International Earth system model development. The research was supported by the national key R & D Program (No. 2020yfa0607801) and the National Natural Science Foundation of China (No. 42075166, 41975119 and 41830966), as well as major national science and technology infrastructure projects Support of "earth system numerical simulation device".
Thesis information:
Wu, C.*, Lin, Z.*, Liu, X., Ji, D., Zhang, H., Li, C., & Lin, G. (2021). Description of dust emission parameterization in CAS-ESM2 and its simulation of global dust cycle and East Asian dust events. Journal of Advances in Modeling Earth Systems, 13. e2020MS002456. https://doi.org/10.1029/2020MS002456
图1 CAS-ESM2中基于风沙物理学的起沙模型示意图
图2 基于CAS-ESM2估算的全球沙尘收支图像
图3 CAS-ESM2和CESM2对塔克拉玛干沙漠沙尘天气频次的模拟与观测的对比：（左）沙尘天气频次的季节变化；（右）不同强度沙尘浓度的频次分布