Linear correlation coefficients between models s20rts and sb4l18

• left plot: total correlation for l_max=20 (solid,magenta line) and l_max=8 (dashed, pink line) as a function of depth z
• middle plot: correlation r as a function of depth z and spherical harmonic degree l
• right plot: model RMS on a logarithmic scale

• model s20rts: view normalized power per degree, power per degree, radial correlation, or
  compare with pmean hwe97p kh00p bdp98 bdp00 pb10l18 smean grand ngrand saw24b16 sb10l18 sb4l18 s20a s362d1 rum lrr98d stb00d
• model sb4l18: view normalized power per degree, power per degree, radial correlation, or
  compare with pmean hwe97p kh00p bdp98 bdp00 pb10l18 smean grand ngrand s20rts saw24b16 sb10l18 s20a s362d1 rum lrr98d stb00d