On Thursday, November 22, 2012 8:37:15 PM UTC+13, vaggelis wrote: > Hello, > > I have a time series of hourly production of a PV.The time series has a 24-hour seasonality. > > How can i remove the seasonality so as to transform my Time series to a stationary TS??
Is the "seasonality" roughly constant from day to day? If so, you can take the average over each hour to obtain the mean 24-hour cycle, then subtract it. Assuming y is a column vector of data for an integer number of days: y1=reshape(y,24,); ycyc=mean(y1,2); % This is the mean daily cycle ndays=size(y1,2); ycycall=repmat(ycyc,ndays,1); % Set up column vector of daily cycle ystat=y - ycycall;