Two-dimensional atmospheric transport and chemistry model: numerical experiments with a new advection algorithm

Area of Science:

• Atmospheric Science
• Computational Fluid Dynamics
• Numerical Modeling

Background:

• The California Institute of Technology-Jet Propulsion Laboratory (CIT-JPL) two-dimensional model of the middle atmosphere requires accurate advection schemes.
• Prather's (1986) advective scheme is a foundational method used in atmospheric modeling.

Purpose of the Study:

• To generalize Prather's advective scheme to incorporate higher-order moments.
• To evaluate the enhanced scheme's performance with chemical reactions and eddy diffusion.
• To compare the new algorithm against a standard fourth-order finite difference scheme.

Main Methods:

• Generalization of Prather's advective scheme to include higher-order moments.
• Numerical experiments involving clock motion and pure advection in two dimensions.
• Comparison of results with analytic solutions to assess accuracy and diffusion.

Main Results:

• The generalized advective scheme faithfully preserves concentration profiles.
• The enhanced algorithm exhibits negligible numerical diffusion.
• The new scheme demonstrates superior performance compared to a typical fourth-order finite difference scheme.

Conclusions:

• The generalized advective scheme offers significant improvements for middle atmosphere modeling.
• The algorithm's ability to minimize numerical diffusion is crucial for accurate simulations.
• This enhanced scheme provides a more reliable tool for studying atmospheric dynamics and chemistry.