[ncl-talk] nighttime zero cape from skewT_PlotData ?

[Kyle Griffin]

Your skew-t, while helpful, remains of limited use without information as
to where it is located on your map. Can you give us more info, and are you
sure you are using data for the correct location?

Have you considered these values may be different types of CAPE? (e.g.
SBCAPE, MLCAPE, MUCAPE?)

>From your sounding, there is zero surface-based CAPE. If you use the most
unstable parcel (i.e. the one with highest CAPE), you may be able to get a
small positive value of CAPE by lifting the parcel from the nose of the
thermal inversion near the 950 hPa level.

A quick run through the data values output across the top of the sounding
appear to agree nearly perfectly with your sounding data (LCL pressure, LCL
temperature, etc.)

I'm not familiar with the particular CAPE calculation functions, but I
believe the documentation or the code itself will likely help you make this
determination.


Kyle

On Wed, May 11, 2016 at 5:10 PM xiaoming Hu <yuanfangcan at hotmail.com> wrote:

> I got 0 cape from skewT_PlotData   always during nighttime.
>
>
>
> which is different from what I got from
>   cinfo = wrf_cape_2d(pres , tk, q, z, HGT, PSFC, True )
>   mcape = cinfo(0,:,:)
>
>
> http://www.caps.ou.edu/micronet/WRF-UCM/FocusON_OKC/WRFV3.7.1/with_rr_fixed/wrfNCEP_DOE2d_UCM_Snudge_WangRec53waveCU14YSUparameterp_1.2005060100/wrfout_d01_CAPE_1.png
> Apparently wrf_cape_2d  gives non-zero values.
>
> Anything wrong for one of them?
>
> Thanks
> Xiaoming
>
>
>
> ------------------------------
> Date: Fri, 22 Apr 2016 14:51:24 -0600
> Subject: Re: [ncl-talk] Where to download 6.4.0 right now?
> From: haley at ucar.edu
> To: yuanfangcan at hotmail.com
> CC: ncl-talk at ucar.edu
>
> Xiaoming,
>
> We've been testing "conda" as a distribution mechanism for NCL, and we
> have a test version of NCL that you can try using this.  Please note that
> this is a TEST version, as we haven't released V6.4.0 yet.  This version
> does have the cape_2d fix.
>
> Here's how to get "conda"
>
> 1) Download "miniconda" from:
>
> http://conda.pydata.org/miniconda.html
>
> Get the Python 2.7 version and not Python 3.5.
>
> 2) Install from a UNIX terminal window by typing:
>
> conda create --name ncl_test --channel dbrown --channel khallock ncl
>
> This creates a conda environment called "ncl_test" in which you switch in
> and out of from your default version of NCL
>
> 3) To activate the "ncl_test" environment, type (from bash/sh):
>
> source activate ncl_test
>
> 4) Test NCL by typing:
>
> ncl -V
> ng4ex xy01n -clean
>
> If you have problems with the conda version, we would like to know about
> this right away, as we are still testing it out.
>
> Thanks,
>
> --Mary
>
>
> On Fri, Apr 22, 2016 at 2:26 PM, xiaoming Hu <yuanfangcan at hotmail.com>
> wrote:
>
> I noticed
> *cape_2d* Returns 2D fields mcape/mcin/lcl/lfc *Bug fixed in NCL V6.4.0*
>
> Where to download 6.4.0 right now?
>
> Thanks
> Xiaoming
>
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