Lin Zhang’s group
Atmospheric chemistry plays an indispensable role in the evolution of atmospheric gases and aerosols, and is also an essential component of the climate system due to its active interactions with atmospheric physics and biogeochemistry on various spatiotemporal scales. Climate modulates the natural emissions, chemical kinetics, and transport of atmospheric gases and aerosols, while changes in many of these constituents alter the radiative budgets of the climate system and also influence the biosphere. Climate-chemistry coupled models are indispensable tools to quantify climate-chemistry interactions and to predict future air quality. Development of climate-chemistry coupled model has been identified as a research frontier for atmospheric chemistry, and also a priority for CSM development particularly in China.
Prof. Lin Zhang’s group has been collaborating with National Climate Center and Harvard University to enable online simulation of GEOS-Chem atmospheric chemistry in the BCC-Climate System Model (CSM). After 5-year efforts, they have successfully developed a new global atmospheric chemistry-general circulation model, BCC-GEOS-Chem v1.0, which represents an important step for the development of fully coupled earth system models (ESMs) in China.
Figure 1 presents the framework of the BCC-GEOS-Chem v1.0. The model includes interactive atmosphere (including dynamics, physics, and chemistry) and land modules, and other components such as ocean and sea ice are configured as boundary conditions for this version. Dynamic and physical parameters from both the atmosphere and the land modules are then used to drive the GEOS-Chem chemistry and deposition of atmospheric gases and aerosols.
Comparisons with observations of atmospheric compositions demonstrate that the model well captures the spatial distributions and seasonal variations in tropospheric ozone. The model diagnosed global tropospheric ozone burden, OH concentration, and methane chemical lifetime are consistent with recent multi-model assessments. The spatiotemporal distributions of NO2, CO, SO2, CH2O, and aerosols optical depth are generally in agreement with satellite observations.
The study has published in Geoscientific Model Development in 2020. The BCC-GEOS-Chem v1.0 model will have attractive scientific and operational applications (e.g., sub-seasonal air quality prediction). Future work will implement the a more detailed stratospheric chemistry and better diagnose radiative transfer and aerosol-cloud interactions in the model.
Figure 1. Schematic diagram of the BCC-GEOS-Chem v1.0 model framework.