Xfilter and checkerboards

Xfilter and checkerboards August 15, 2011 Arthur Taylor MDL/NWS/NOAA

X-Filter • Background • June 2011 – C. Forbes and A. Taylor introduced the cross laplacian as part of the smoothing methods that the SLOSH model uses to resolve checkerboarding • NHC reported that this did not solve the problem. • Aug 2011 – A. Taylor looked into the areas of concern. They appear to be areas with < 1 feet above ground level values. • Observation: The smoothing code ignores land wetted less than HCRT. So no smoothing took place. • Options: • A) Change HCRT from 0.5 to 0.1 feet. • B) Detect checkerboarding only for water above grid cell > 0.5 • Note: Using HCRT = 0.0 will flood entire basin.

d215L020_R20_Dhigh (HCRT=0.5)(70,116); (76,113) Above Datum Above Ground Level

d215L020_R20_Dhigh (HCRT=0.1)(70,116); (76,113) Above Datum Above Ground Level

a105L030_R20_Dhigh (HCRT=0.5)(84,93); (70,92); (16,167); (60,156) Above Datum Above Ground Level

Xfilter and checkerboards

Xfilter and checkerboards

Presentation Transcript

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