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Zhuoqun Li, Fellowship Grant 2014

Momentum and mass transfer from atmosphere to rough surfaces

Figure: Simulation result of particle laden flow over rough surface. The points are particles. The color of particles represents velocity magnitude, red for high speed and blue for low speed, the maximum wind speed is 20 ms-1. The outline of the rough surface is also shown. (Figure 4.4 from the PhD dissertation of Zhuoqun Li, 2015)

During my GSGS fellowship (1.9.2014-15.12.2014), I submitted my PhD dissertation and arranged the defense. I passed the examination and acquired the doctor’s degree. In the meantime, I had also submitted a manuscript ‘A physical model for drag and drag partition on rough surfaces’ to Boundary-Layer Meteorology, which has already been accepted. Moreover, the European Geosciences Union (EGU) accepted my abstract for an oral presentation at the General Assembly in Vienna in April 2015.

My dissertation focused on two fundamental meteorological subjects, the momentum transfer and mass transfer from the atmosphere to rough surfaces. These two subjects are fundamental problems for meteorology, environmental science and industry. The transfer of momentum is crucial for the transfer of mass, heat, and water vapor in the boundary layer. The mass transfer, e.g., dry deposition, is a key process of the dust cycle. Both processes are closely related, but not well understood, particularly on rough surfaces or in unsteady conditions. In my dissertation, I improved the theories of momentum transfer and the parameterization for dry deposition. The new theories are based on numerical simulations of the air flow and dust flux over rough surfaces.

The paper that I submitted to Boundary Layer Meteorology proposed a physical model, which considers more conditions than previous models. It fixed several fatal problems in existing theories using more reasonable mathematical expressions. To validate the estimations in my new model, they are compared to existing laboratory measurements.

In future, I will carry on my work on momentum and mass transfer. The new theory of momentum will be improved for random surfaces, and deposition theory will be improved for more complex conditions.

For my next step, I will first go back to China and work in Lanzhou University focusing on publishing further work, I carried out during my PhD study, and I will improve my theories. After that, I will continue to seek opportunities to apply for related projects. An international cooperative project with my colleagues in GSGS will be my first choice. 

Zhuoqun Li

GSGS Fellow from 01/09 – 15/12/2014

Grant No. GSGS-2014-F05

Title of research project: Momentum and mass transfer from atmosphere to rough surfaces

Supervisor: Prof. Dr. Yaping Shao

Institute of Geophysics and Meteorology

University of Cologne