how to take seasoanal mean

I have data with 231x141x6408 dimension, it is daily mean data of January, February, and December from 1950-2020. How to take seasonal mean from the data for each year. so I finally obtain data with dimension 231x141x71, please note there are leap years.

Link of the data

https://drive.google.com/file/d/1PeZKZZIJN7LBXxRn9omSyQN3UU33TBNX/view?usp=sharing

Answer 1

[Pavan Sahith]

Hello ,

I noticed you're seeking assistance with calculating the seasonal mean of your data.

For that you can refer to this sample code which will guide you.

Since I couldn't access the link provided , created some sample data to work with.

rows = 231;
cols = 141;
% Total days for 71 years, assuming 91 days for non-leap years and 92 for leap years
% Leap years add an extra day: 18 leap years in the range 1950-2020
totalDays = (71 - 18) * 91 + 18 * 92;

data = rand(rows, cols, totalDays);

Create an array to store the seasonal mean results with dimensions 231x141x71.

seasonalMean = zeros(231, 141, 71); 

Now, Calculate the mean for the specific months for each year, considering leap years.

startIndex = 1;
for year = 1:71
    % Check for leap year
    if mod(1950 + year - 1, 4) == 0 && (mod(1950 + year - 1, 100) ~= 0 || mod(1950 + year - 1, 400) == 0)
        daysInMonths = 31 + 29 + 31; % Adjust for leap year
    else
        daysInMonths = 31 + 28 + 31; % Non-leap year
    end
    
    endIndex = startIndex + daysInMonths - 1;
    
    % Calculate the seasonal mean for the current year
    seasonalMean(:,:,year) = mean(data(:,:,startIndex:endIndex), 3);
    
    % Update the startIndex for the next year
    startIndex = endIndex + 1;
end

You can also refer to the following MathWorks documentation to learn more about 'mean' and 'mod':

mean- https://www.mathworks.com/help/matlab/ref/mean.html

mod- https://www.mathworks.com/help/matlab/ref/mod.html

I hope this information helps you move forward with your task!