[ncl-talk] Difference plot contour map emply

[Debasish Hazra]

Hi,

I have attached the code I used to calculate difference between two models
at a single time step. Model 1 (grib2 file) dimension is [lat | 181] x [lon
| 360]  and coordinates are  lat_0: [90..-90], lon_0: [
0..359].  _FillValue :   1e+20

second one (netcdf) dimension [lat | 180] x [lon | 360] and coordinates are
lat: [-89.5..89.5] , lon: [-179.5..179.5].  _FillValue :   -9999

  I regrid the 2nd to the first one co-ordinate and make a difference plot
over different regions.

Q1. If the 1st model latitude is [90..-90] and regrided 2nd model latitude
coordinates are latitude is [-90..90], does it have any impact on the
difference plot ?

I have attached the code, model 1 output. I ftp the second model output
(icap_2015091500_MME_modeaod550.nc) as that is of larger size.

Thanks.
Debasish


On Tue, Apr 12, 2016 at 1:57 PM, Mary Haley <haley at ucar.edu> wrote:

> Debasish,
>
> Without seeing your code, we have no way of helping you debug it.
>
> I recommend using print statements to verify that your data after
> interpolation is correct. If your interpolated data array is called
> (data_interp):
>
> printVarSummary(data_interp)
> printMinMax(data_interp,0)
> print(num(ismissing(data_interp)))    ; count the number of missing values
>
> If you continue to have problems, it would help if we could see a plot or
> some code.
>
> --Mary
>
>
> On Mon, Apr 11, 2016 at 6:57 AM, Debasish Hazra <debasish.hazra5 at gmail.com
> > wrote:
>
>> Hi,
>>
>>  I am using NCL (v6.3) to make a difference plot between two model
>> outputs. First one (grib2 file) dimension is [lat | 181] x [lon | 360]  and
>> coordinates are  lat_0: [90..-90], lon_0: [ 0..359].  _FillValue :   1e+20
>>
>> second one (netcdf) dimension [lat | 180] x [lon | 360] and coordinates
>> are lat: [-89.5..89.5] , lon: [-179.5..179.5].  _FillValue :   -9999
>>
>> To make both of them equal dimension before doing differences, I used "linint2"
>> function to interpolate 2nd one to the dimension of first. However, after
>> doing simple difference plot between the interpolated one and the first
>> output, I am getting all constant value and map plot remains empty.
>> Individual plot of these 2 dataset show lot of differences. Is it because I
>> did not assign fillvalue after interpolation , or something else ? Any
>> suggestions.
>>
>> Thanks
>> Debasish
>>
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