Re: [ferret_users] vertical weighted averagng

[Martin Schmidt <martin.schmidt@xxxxxxxxxxxxxxxxx>]

Hi Robert,

a first inspection with ncdump shows an overly long file history. There is a flag in nco to supress this. 

I have the feeling the file is aggregated from time slice files using nco. This is not needed if you are working locally, since ferret can do the aggregation for you. Please consult the manual. For sure, it is appropriate to select one grid point, to send the file via mail.

The first step should be to read the file header with ferret
ferret

use sample_TS.nc
show data

You may also want to see the vertical distribution of grid points:

list z[gz=temp]

To average temp, you may use the ferret operator @ave

list/l=1 temp[z=@ave]

You may plot a time series

plot temp[z=@ave]

This looks simple, but for sure ferret makes assumptions where exactly the grid points are positioned within the grid cells. Any information on this like on cell boundaries is missing in the file. So this needs some thoughts.

So far, the result should be fine. Hope this gets you started. I suggest, to have a look into the excellent manual and go through the tutorial.

Best,
Martin




On 03/02/2017 02:56 PM, Osinski, Robert FORNATL, PL wrote:

Dears,
sorry if I was not clear enough with my question.
I have model outputs which are not equally spaced in vertical and I'd like to know how to calculate for instance weighted mean in vertical temperature. As example I attached a file with results from single point,
Thanks in advance,
Robert Osinski
NPS 

    

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From: saurabh rathore [rohitsrb2020@xxxxxxxxx]
Sent: Wednesday, March 01, 2017 6:58 PM
To: Osinski, Robert FORNATL, PL
Cc: ferret_users@xxxxxxxx
Subject: Re: [ferret_users] vertical weighted averagng

Hi,

I don't know exactly about the question you are asking but i think its very simple to do.

suppose you are having var(i,j,k,l)

so its simply you can do to average about a single point also suppose you are having k=1:27, 1 corresponds to surface and you want to make average of your 5th level only then you have to do like this

let lev5_ave=var[k=5@ave]

this way you can do to average out the level and it works also.

I hope this is the thing you were asking.

regards, saurabh

On Wed, Mar 1, 2017 at 7:03 PM, Osinski, Robert FORNATL, PL <rosinski@xxxxxxx> wrote:

Ferreters,
I know that @AVE transformation computes the length-weight average of point in horizontal, but how to calculate weighted average for one point but in vertical?
Thanks in advance,
Robert Osinski
NPS

--

REGARDS

Saurabh Rathore

Research Scholar (PhD.)

Centre For Oceans, Rivers, Atmosphere & Land Science Technology

Indian Institute Of Technology, Kharagpur

contact :- 91- 8345984434