Re: [ferret_users] locating the depth of maximum

[William Kessler <william.s.kessler@xxxxxxxx>]

This can be done with @loc. From the manual:

Note that the transformation @LOC can be used to locate non-constant values, too, as the following example illustrates:

Example: locating non-constant values

Determine the depth of maximum salinity.

yes? LET max_salt = salt[Z=@MAX]
yes? LET zero_at_max = salt - max_salt
yes? LET depth_of_max = zero_at_max[Z=@LOC:0]

> On Mar 16, 2022, at 7:35 AM, saurabh rathore <rohitsrb2020@xxxxxxxxx> wrote:
> 
> Dear Ferreters
> G'day
> 
> I want to locate the depth of maximum of AMOC in my model data. Here is the data
> 
>    name               title                                          I         J             K         L
>  ATLMOC   ATL[I=@SUM,K=@RSUM]            ...       1:331     1:75      1:140
> 
> !!!!! for finding maximum of ATLMOC for a fixed latitude (J=246) and depth level range (K=36:65) for time (L=140)   !!!!!!!!
> 
> list ATLMOC[j=246,k=36:65@max,l=140]
> results = 1.670E+07
> 
> !!!  Now I want to locate the depth of this maximum at j=246 and l=140 but this command is not working and it is not showing any value  !!!!!!
> list ATLMOC[j=246,k=@loc:16700000,l=140]
>              
> VARIABLE : DEPTH (m) of 16700000 in ATL[I=@SUM,K=@RSUM] (m)
>                         X=0.5:360.5, Z=0:6004
>                        FILENAME : moc140.nc
>                        Y        : 246
>                       DEPTH (m): 0 to 6004 (location of 16700000)
>                       TIME     : 02-JUL-0140 12:00 NOLEAP
>                       ....
> 
> One can see the depth and its level (k) for the maximum value by
> 
> list ATLMOC[j=246,k=36:65,l=140]
> 
> 333.9   / 36:  8.721E+06
>  370.7   / 37:  9.703E+06
>  411.8   / 38:  1.076E+07
>  457.6   / 39:  1.186E+07
>  508.6   / 40:  1.296E+07
>  565.3   / 41:  1.399E+07
>  628     / 42:  1.486E+07
>  697.3   / 43:  1.565E+07
>  773.4   / 44:  1.632E+07
>  856.7   / 45:  1.670E+07  !!! depth level of maximum value !!!!!1
>  947.4   / 46:  1.660E+07
>  1045.9  / 47:  1.601E+07
>  1152    / 48:  1.506E+07
>  1265.9  / 49:  1.395E+07
>  1387.4  / 50:  1.277E+07
>  1516.4  / 51:  1.150E+07
>  1652.6  / 52:  1.006E+07
>  1795.7  / 53:  8.410E+06
>  1945.3  / 54:  6.652E+06
>  2101    / 55:  4.997E+06
>  2262.4  / 56:  3.281E+06
>  2429    / 57:  1.515E+06
>  2600.4  / 58: -3.571E+05
>  2776    / 59: -1.591E+06
>  2955.6  / 60: -2.326E+06
>  3138.6  / 61: -2.764E+06
>  3324.6  / 62: -2.772E+06
>  3513.4  / 63: -2.801E+06
>  3704.7  / 64: -2.813E+06
>  3898    / 65: -2.774E+06
> 
> So I want to know how to locate the depth for the maximum value? I can not understand what mistake I am doing for this simple calculation. 
> 
> Thanks in advance. 
> 
> Cheers, Saurabh
> 
> -- 
> 
> 
> REGARDS
> 
> Saurabh Rathore
> Research Scholar (PhD.)
> Centre For Oceans, Rivers, Atmosphere & Land Science Technology
> Indian Institute Of Technology, Kharagpur
> contact :- 91- 8345984434

(Still) working at home: +1 206-228-7330 (m)