[Thread Prev][Thread Next][Index]

[ferret_users]wind frequency from zonal, meridional wind

Dear Ferreters,

I have daily data set. I want to visualize the most frequent wind direction for a region. I have u and v variables.

1. First i count the number of days belonging to (16) directions with "tan" function (N, NNE, NE, ENE...)

let ENE=if (u lt 0 and v lt 0) and (tan(u/v) le 0.6682) and (tan(u/v) gt 0.1989) then 1
let enedir=ene[l=@sum]

and so on...

2. Then i try to write out for every (lon-lat) point  the frequency of the direction (actually the number of the most frequent direction):

repeat/j=1:61:1 (repeat/i=1:97:1 (let freq={`ndir`,`nnedir`,`nedir`,`enedir`,`edir`,`esedir`,`sedir`,`ssedir`,`sdir`,`sswdir`,`swdir`,`wswdir`,`wdir`,`wnwdir`,`nwdir`,`nnwdir`} ;\
let winddirmax=freq[x=@max]; let wind=freq[x=@loc:`winddirmax`];\
save/file="./winddir.6190.nc"/ilimits=1:97/jlimits=1:61/i=`i`/j=`j`/clobber wind))

It works, it says:

!-> REPEAT: I=63
 !-> DEFINE VARIABLE freq={28,12,16,28,165,78,75,47,29,10,21,38,221,82,83,67}
 !-> DEFINE VARIABLE wind=freq[x=@loc:221]
 !-> LIST/FORMAT=CDF/file="..."/ilimits=1:97/jlimits=1:61/i=63/j=1/append/clobber wind
 listing to file ...

But as for the output file, it seems, it didnt work:
yes? use ...
 name     title                             I         J         K         L
 WIND     FREQ[X=@LOC:221]                 ...       ...       ...       ...
yes? list wind
             VARIABLE : FREQ[X=@LOC:221]
             FILENAME : winddir.6190.nc
             FILEPATH : /home/szabop/aladin_arpege/

Any suggestion will be appreciated (either in solving the technical problem). Thanks a lot,

Peter szabo

[Thread Prev][Thread Next][Index]

Contact Us
Dept of Commerce / NOAA / OAR / PMEL / TMAP

Privacy Policy | Disclaimer | Accessibility Statement