Spatial Power Spectra Density (PSD) Analysis

I have performed PSD on frequency domain (see first attachment) and I am looking for guidance/ directive(s) or script code used for the Spatial Spectral Density analysis of SST(time,lat,lon) data on lat-lon domain. That is applying DFT to the timeseries of SST at each grid point and present the resulting gridded spectra as power spectra density map (see second attached).