[Met_help] Question, comments

[John Halley Gotway]

James,

My responses are inserted inline below:

Correia, James wrote:
> Hi
> I have been using MODE on 3 hourly rainfall from a regional climate model
> (i.e. Been staring at a lot of data).
> 
> Question:
> Is there a way to turn off 1 or 2 of the plots produced by MODE in the
> output postscript file?

Regarding turning off some of the plots that MODE produces... here are your options:

(1) On the command line, you can turn OFF the postscript plots using the "-plot" command line option.
(2) If you're scripting your calls to MODE, you could have MODE produce them, and then use something like the "psselect" command to pull out the pages you'd like to keep.  And then delete the original
PostScript file from MODE.
(3) You could edit the file "mode.cc" to suppress the creation of some pages, and then recompile MET.

If you need help doing (2) or (3), just let me know and I'd be glad to help.  Which page(s) would you like to retain?

> 
> I have been working on the assumption that only 1 time per input file is
> required. Is this correct or can MODE handle more than 1 time per file?
> 

As for whether or not MODE can handle multiple times in a file, I believe that the answer is no.  But let me explain.

If the MODE configuration file, you use the "fcst_grib_code" and "obs_grib_code" to specify the name of the field and accumulation interval in which you're interested.  For example:
fcst_grib_code = "APCP/A3";
obs_grib_code  = "APCP/A3";

MODE will open the input GRIB files (specified on the command line) and look for the first GRIB record that contains (in this case) precipitation accumulated over 3 hours.  If your GRIB file contains
multiple records that meet this criteria (maybe valid at different times), it'll just grab the first one it encounters.

> 
> Comments:
> I generally like the way code operates. However, with 3 hourly output or
> longer there is a dependency that large rainfall rate grid boxes, once
> convolved, effectively increase the area of the object. In one instance I
> have a precipitation field that is relatively broken (mixed low and high
> precipitation rates and zero's). The resulting object is quite large
> stretching from corner of the domain to the southern end of the domain. If
> you would like I can send an image.

As you mention below, I'd suggest continuing to play around with the configuration settings to get MODE to define objects the way they want them to look.  By decreasing the convolution radius you'll
get objects that are smaller and less smooth.  It can be set as low as 0 (= no convolution), but the big downside is that with too many objects, MODE will run pretty slowly and there will be too much
output to deal with.

Ultimately, it's up to you to decide what scale you're interested in.  We often run MODE here multiple times using different configuration to look at performance at different scales.

> 
> Is it possible that an additional measure be output that includes the
> percent of the object area with restored grid point precipitation values
> which fall at or below the 1st and/or second threshold value? I guess this
> would be a confidence measure indicating if this object is uniformly filled
> or chaotically filled.

The "AREA_FILTER" column in the current MODE output contains a count of the number of points inside an object that contain non-zero values.  So for precipitation, looking at AREA_FILTER/AREA would
give you can indication of how "dense" the raw data is in the object.  However, perhaps it'd be better to redefine this column to indicate the number of grid points in the object that meet the
threshold criteria, rather than simply being non-zero.  That's actually probably a better approach anyway since it'd apply well to continuous fields too - rather than just precip.

Would that meet your needs?

If so, I could probably provide you with an updated file and have you recompile MET.

Hope that helps,
John Halley-Gotway
johnhg at ucar.edu

> 
> Generally I have been playing with both threshold values, and the convolved
> radius. I am only working with model data so I am not merging objects.
> 
> Thanks
> jimmyc
> 
> 
> James Correia Jr., PhD
> Climate Physics Group
> Post. Doc.
> Pacific Northwest National Lab
> 
> "Wisdom. Strength. Courage. Generosity. Each of us are born with one of
> these. It is up to us to find the other three inside of us."
> -Into the West
> 
> 
> 
> 
> 
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