Error Rain/Snow Option

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Paul Wolyn, modified 8 Years ago.

Error Rain/Snow Option

Youngling Posts: 2 Join Date: 9/24/12 Recent Posts

WFO Pueblo ran across an error with the top down grids and the rain/snow only option. It appears the top-down grids are created every six hours and the rain/snow only option worked well for these grids. These six hourly maxTwAloft grids had temperatures of -0.1 or less. However, the grids which are interpolated between these six hour grids can have MaxTwAloft greater than -0.1C. In fact some of the MaxTwAloft grids had values above 0.1C with the Ptype being freezing rain. There appears to be a problem with the interpolation scheme. If the two grids at either end of the interpolation period have values of -0.1 at a point, should all the grids interpolated between these two grids also have -0.1C? If some type of spline is used for interpolation, then we need to be sure that forcing values to be -0.1C or less occurs after the interpolation.

Andy Just, modified 8 Years ago.

RE: Error Rain/Snow Option

Youngling Posts: 89 Join Date: 6/2/15 Recent Posts

Paul,

Typically interpolation between 2 grids with -0.1 values would only fill in -0.1 value grids between them. The only thing I can think of is if something is going on with GFE's default interpolated algorithm for MaxTwAloft. You could try in your siteGfeConfig file adding the following:

MaxTwAloft_interpolateAlgorithm = "LINEAR_NOADVECT"

I could also adjust the Rain/Snow option so it runs across the entire MaxTwAloft grids after they are populated, which would be a little slower but help correct this issue if it's still going on.