Add functionality to calculate and plot mean and rolling mean of spectra#2245

Carol Halliwell (cehalliwell) wants to merge 5 commits into

mainMetOffice/CSET:mainfrom

215_regional_power_spectra_new_operator_DCT_aggregateMetOffice/CSET:215_regional_power_spectra_new_operator_DCT_aggregateCopy head branch name to clipboard