Large-Eddy Simulation #195: (IBL)

LES RUN #195: This was an attempt to duplicate & compare with LES #181 but with just two improvements: 1) the grid is 300-m taller by stretching the cells above 675 m, and 2) the passive tracer is restored to the initial profile in the restoring zones.

But, after run #181, we implemented an Arakawa & Lamb advection routine that was used on #195. This new scheme has improved conservation properties by implementing a 3-D averaging procedure designed to maintain better momentum conservation and three-dimensional consistency. The effect is to eliminate spurious 3-D small-scale rolls that developed over the land resulting from the Sadourney scheme. See figure below.

The following two images show the pressure-perturbation at 3288 s after initialization on vertical and horizontal planes. Contours on the vertical slice are of potential temperature. The zero-isoline of pressure perturbation is shown for clarity on the horizontal slice.

This simulation was run out to 3300 s (50-minutes) past initialization and terminated. LES #196 is being run to resume where this left off, and it has the single row of random wiggles turned back on.

This simulation took 18-days to run on our j50. Click here to see the NMSTASK file of LES #195.

The following is a horizontal slice through the bottom of the model domain (7.5 m above the surface) over the water only. The output has been folded over once in the north-south direction to help your eye follow coherent structures across the domain. This is an east-west subset of the model domain.

The following is an east-west vertical slice through the model domain.

The following is a horizontal slice through the bottom of the model. The entire area is shown.

The following is the same horizontal slice as above, but for LES#181.

UW Lidar // June 13, 2000 //

Return to the Index