how to combined monthly data in sequence?

hello all,

I have a time series data for 10 year (lat X lon X 120). For taking monthly mean of every jan, feb.... dec, I have separated jan to dec data

jan = data(:,:,[1:12:10]);

feb = data(:,:,[2:12:10]);

mar = data(:,:,[3:12:10]);

aprl = data(:,:,[4:12:10]);...........

Then I have taken mean,

jan_mean = mean(jan(:,:,1:10),3); feb_mean = mean(feb(:,:,1:10),3); .......................................................dec_mean = mean(dec(:,:,1:10),3);

For calculation of anomaly, Anom_jan = jan - jan_mean, Anom_feb = feb - feb_mean......................

Now, I want to combined all these Anom timeseries in seuence (lat X lon X 120).

how to merge theses timeseries in sequece of jan to dec of ever year?

Answer 1

[Manikanta Aditya]

Hi @Vedanta,

You can concatenate the anomaly time series data for each month along the third dimension using the cat function in MATLAB.

Here’s how you can do it:

Anom_combined = cat(3, Anom_jan, Anom_feb, Anom_mar, Anom_apr, Anom_may, Anom_jun, Anom_jul, Anom_aug, Anom_sep, Anom_oct, Anom_nov, Anom_dec);

This will create a new 3D matrix Anom_combined where the third dimension is the time series data for each month from January to December for every year. The size of Anom_combined will be (lat X lon X 120), same as your original data. Replace with your actual varible names.

I hope this clarifies

[Vedanta]

this command (cat) is just merging the data. Anom_jan is having january value for 10years, similarly Anom_feb is having feb months values for 10year. I want datasets in monthly series... jan to dec of first year, jan to dec of seond year............. jan to dec of 10th year

[Manikanta Aditya]

I understand. You want to concatenate the anomalies in a way that represents the monthly sequence for each year, rather than all of the same months together.

Here is how you can do it:

% Assuming Anom_jan, Anom_feb, ..., Anom_dec are already calculated

% Preallocate the combined anomaly matrix
Anom_combined = zeros(size(Anom_jan, 1), size(Anom_jan, 2), 120);

% Number of years
num_years = 10;

% Loop through each year and interleave the monthly data
for year = 1:num_years
    for month = 1:12
        % Determine the correct index in the combined matrix
        idx = (year - 1) * 12 + month;
        
        % Assign the monthly anomaly to the correct position
        switch month
            case 1
                Anom_combined(:, :, idx) = Anom_jan(:, :, year);
            case 2
                Anom_combined(:, :, idx) = Anom_feb(:, :, year);
            case 3
                Anom_combined(:, :, idx) = Anom_mar(:, :, year);
            case 4
                Anom_combined(:, :, idx) = Anom_apr(:, :, year);
            case 5
                Anom_combined(:, :, idx) = Anom_may(:, :, year);
            case 6
                Anom_combined(:, :, idx) = Anom_jun(:, :, year);
            case 7
                Anom_combined(:, :, idx) = Anom_jul(:, :, year);
            case 8
                Anom_combined(:, :, idx) = Anom_aug(:, :, year);
            case 9
                Anom_combined(:, :, idx) = Anom_sep(:, :, year);
            case 10
                Anom_combined(:, :, idx) = Anom_oct(:, :, year);
            case 11
                Anom_combined(:, :, idx) = Anom_nov(:, :, year);
            case 12
                Anom_combined(:, :, idx) = Anom_dec(:, :, year);
        end
    end
end

Hope this helps!