[ncl-talk] Extracting temperature from specific grids where LU_INDEX = 2

Imran Hosen hosen.imran09 at gmail.com
Tue Mar 14 03:06:30 MDT 2017

```Dear Guido and Barry,

Thank you so much for your heartfelt and prompt response. Yes, your
suggestions are working fine for my script.

wrote the script as follows:

T2 = f_1->T2(:,:,:)
LU_INDEX = f_1->LU_INDEX(0,:,:)       ; (LU_INDEX = landuse index)

The script works fine and it is extracting both real values and FillValues
(missing values). *But, I want to extract only real values*. I have seen
that "*ind*" function can be used for extracting real values for
*one-dimensional
array*. Could you please suggest me what function I can use to extract the
real values for *two-dimensional array*.

Your further suggestion will be highly appreciated.

Kind regards,
Imran

On Tue, Mar 14, 2017 at 6:55 PM, Guido Cioni <guidocioni at gmail.com> wrote:

> Hi Imran,
> unfortunately I’m not really an expert of WRF, so I’m going to give you a
> general hint which may work. You should be more precise next time as
> generally people do not know what is LU_INDEX and what is its structure ;)
>
> I assume that you want to extract temperature, which is 3-D (time, lat,
> lon) using a mask array LU_INDEX which is 2-D (lat, lon). Again, if this
> assumption is wrong please be more specific. You have many choices, but I
> believe that for the sake of clarity you may want to go for an array which
> has the same dimensions but missing values where LU_INDEX is not 2. So you
> may want to do something like this:
>
>
> You need to have a Missing Value attribute set for the T2 variable of
> course. As a result you will get an array with the same dimensions, so that
> it’s easier to compare with the original one, but with Missing Values where
> your condition is False, so that for every computation these points will
> not be considered. You can achieve something similar with the where
> function. Please have a look here (http://www.ncl.ucar.edu/
>
> Cheers
>
>
> Il giorno 14 mar 2017, alle ore 04:38, Imran Hosen <
> hosen.imran09 at gmail.com> ha scritto:
>
> Dear NCL users,
>
> Good day!
>
> I'm a new user of NCL. I want to extract temperature (T2) from wrfout file
> for the specific grid points where the LU_INDEX = 2.
>
> For example,
> T2 = f->T2(:,:,:)
>
> It will extract temperature for whole domain for all time steps. In my
> case, I only want to extract temperature for all time steps but for the
> specific grids which grids represent LU_INDEX = 2.
>
> Could you please suggest how to do it. I would grateful to you if anyone
>
>
> Kind regards,
> Imran
>
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--
*Md. Imran Hosen*
PhD Student
Victoria University
College of Engineering and Science
Footscray Park Campus
Victoria, Australia
Mob. +61470371562
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