The OSU MMM5 VL2 simulations

 

A plot showing hydrostatic results follows. In this plot the green lines/dots are the VL2 data that I generated by averaging many sols of data centered on the Ls of our experiment. The yellow stars are output from the Ames GCM (height on average is 5 m), the black circles are OSU MMM5 data and the black stars are interpolations to 1.6 m. The middle of the lowest sigma layer in the hydrostatic model is ~2 m on average. Four sols of the simulation were skipped to allow full model spin-up, and the six final sols of output are shown in the plot. Interpolation for temperature was performed with an exponential fit whereas winds were interpolated linearly. We believe that the temperature fit is good for a neutral or stable atmosphere, but during unstable periods the fit is likely quite poor if any significant vertical distance must be interpolated.

The next plot shows results from the nonhydrostatic model. In this experiment the lowest model sigma height was ~25 m, so we do not show an interpolation for winds to 1.6 m, as values essentially become negligible. The fit for temperature is again very good at night, but it is quite terrible for unstable periods (large interpolation distance). We wonder what other methods may be wise to employ here, but we know that without more data from Mars (or a very good terrestrial analogue) to help define this regime we are simply feeling around in the dark putting trust in terrestrial methods. We had initially assumed this run had a bug given the large diurnal cycle in surface pressure (nearly sinusoidal), but after seeing the similar, although not quite so dramatic, results of the other groups we wonder if there may be some reason to suspect some aspect of the nonhydrostatic model dynamics.