how to store data in a matrix?

Hi all,

I want to loop over the third dimension of the 3D matrix and calculate the average then sore the resulted data in a new matrix.

For example:

 U10_series = [];
    for day=1:length(datenum_array); % this time is corresponding to the number of days 
  filename=strcat('./MERRA2_400.tavg1_2d_ocn_Nx.2019',num2str(datevec_array(day,2),'%02i'),num2str(datevec_array(day,3),'%02i'),'.SUB.nc'); 
    %read U10
    U10          = ncread(filename,'U10M');
    U10_box      = U10(lon_range,lat_range,:);
    U10_box_mean = nanmean(U10_box,3);
    U10_series   = [U10_series,U10_box_mean];
end 

where am I mistaken?

The help is much appreciated

Answer 1

[KSSV]

U10          = ncread(filename,'U10M');

If your variable U10M is 3D, the above line reads complete data. Your U10 should be 3D. Now you can apply mean on it by specifying the dimension you want.

Also read about ncread, here you can specify the 3D dimension you want to read in a loop. If it is not clear, attach your file for further help.

[Lilya]

Thank you Sir KSSV!

It is understandable. but when loop through the 3rd dimension is given, the results are becoming repetitive; therefore, the new matrix store these repetitive data, which is not correct.

I've attached some of the files to check that also the first lines that can read the files. Thanks for the help.

datenum_array = [737426:1:737545]; %datenum(2019,01,01) to datenum(2019,04,31)

datevec_array = datevec(datenum_array);

filename=strcat('./MERRA2_400.tavg1_2d_ocn_Nx.20190101.SUB.nc');

lon=ncread(filename,'lon');

lat=ncread(filename,'lat');

lat_range=find(lat<= 27.6 & lat >= 26.8);

lon_range=find(lon<= 35.7 & lon >= 34.6);

[KSSV]

ncfiles = dir('*.nc') ; 
N = length(ncfiles) ; 
for i = 1:N
    ncfile = ncfiles(i).name ;
    lon = ncread(ncfile,'lon') ; 
    lat = ncread(ncfile,'lat') ; 
    u = ncread(ncfile,'U10M') ; 
    v = ncread(ncfile,'V10M') ; 
    % do what you want 
end

[Lilya]

Thank you very much!