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infinitesimal value of chemical species in wrfchem wrfout file

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I am using WRF-Chem v3.6.1 to simulate CO over China. The emission data include anthropogenic emission, fire emission, and biogenic emission. However, I found there are a lot of very small values of CO, O3, etc in the wrfout file, not the initial time. The small value is 1e-16, like missing value. As far as I know, WRF-Chem rarely gives us this small value or missing value. A grid has a small value, not 1e-16, even there is very less emission data in that grid. So I am guessing I got something wrong when I ran the model. Please see the attached namelist.input file and sample plot. Thank you



  • 1plt_dart_wrf_contour_var_wrfout_v04_wrfchem_initial_co_Our.000004.png
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  • namelist.input
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hi Zhifeng,

You will need to give us some more details before we can help you - can you answer the questions below?

What initial chemical conditions are you using (from which global chemical model, and which chemical fields do you use)?

What chemical species is your plot showing, and what are the units for the colour scale?

And please can you explain more clearly, with example values, what you mean by "a small value, not 1e-16"?