People at NCAR: Peter Hjort Lauritzen
The terminator ‘toy’-chemistry test: A simple tool to assess errors in transport schemes
Authors: Peter H. Lauritzen, A.J. Conley, J.-F. Lamarque, F. Vitt, and M.A. Taylor
This test extends the evaluation of transport schemes from prescribed advection of inert scalars to reactive species. The test consists of transporting two reacting chlorine-like species (Cl and Cl2) in the Nair and Lauritzen 2D idealized flow field. The sources and sinks for the two species are given by a simple, but non-linear, ‘toy’ chemistry. This chemistry mimics photolysis-driven processes near the solar terminator. As a result, strong gradients in the spatial distribution of the species develop near the edge of the terminator. Despite the large spatial variations in Cl and Cl2 the weighted sum Cly=Cl+2Cl2 should always be preserved. The terminator test demonstrates how well the advection/transport scheme preserves linear correlations. Physics-dynamics coupling can also be studied with this test. Examples of the consequences of this test are shown for illustration.
Below animations for Cl (upper), Cl2 (middle), and Cly (lower) are shown for CAM-FV (left or upper set of plots) and CAM-SE (right or lower set of plots), respectively. The solid black line shows the location of the terminator. The arrows show the wind vectors for the Nair and Lauritzen idealized 2D flow field.