Vertical loop error for tend_w in mpas_atm_time_integration.F

[wgustafson]

Matus Martini and I discovered a bug at line 2488 of mpas_atm_time_integration.F. This line loops from k=1,nVertLevels to calculate tend_w. However, ru_edge_w(k) is only given values for k=2,nVertLevels.

We believe the appropriate fix is just to change line 2488 to loop from k=2,nVertLevels since the w-tendency is always zero at the bottom anyway, and it is given that value higher up in the subroutine.

-Bill

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William I. Gustafson Jr., Ph.D.
Scientist
ATMOSPHERIC SCIENCES AND GLOBAL CHANGE DIVISION

Pacific Northwest National Laboratory
P.O. 999, MSIN K9-30
Richland, WA 99352
Tel: 509-372-6110
William.Gustafson@pnnl.gov
http://www.pnnl.gov/atmospheric/staff/staff_info.asp?staff_num=5716
http://www.researcherid.com/rid/A-7732-2008

[matusmartini]

Hi Michael,

We noticed NAN values for tend_w at k=1 distributed randomly in blocks around the earth. This is just a cosmetic correction since the tend_w at k=1 do not seem to be used later in the integration.

Matus

Matus Martini
Postdoctoral Research Associate
Atmospheric Sciences and Global Change Division
Pacific Northwest National Laboratory
Tel: 509-372-4082

[mgduda]

Hi, Matus and Bill.

Thanks for catching this; as it's often useful to be able to run the code with floating-point trapping enabled, this is a fix we'll be glad to make. Since the problem is cosmetic, rather than creating another bug-fix release, I'll include the changes in our development repository, and fix fix will appear in the next feature release (2.0) that should be out in a month or two.

Thanks, again!
Michael