2D color time-series plot


I am trying to plot 2D time-series plot (Month&year on X-axis, and hours on Y-axis and parameter showed as colour gradient). I attached a plot I made using simply psxy which is not a smooth one or interpolation is not performed. I never tried to perform interpolation on these types of time-based non-geographical datasets ( I did for gridded geographical data). I tried to use greenspline on these datasets but it gives me an error of -f option and when I used -f with T it gives me a usual error that -R and -D options disagree on the dimension. Can anyone help me with this? Additionally, can we use grdmask to mask the missing values from the file?
Following is a code I used to plot the attached one.

gmt makecpt -CQuaas -T0/3500/20 > map.cpt
cat sam.xyz | gmt psxy -JX$jflg -R$rflg -Bpxa3Of1o -Bsxa1Y -Bpya5f1 -BWSne -Ss0.3/0.00001 -Cmap.cpt -K  -X1.5 > test.ps
# gmt greenspline sam.xyz -Gsam.grd -R$rflg -I10d -fT -D0 -Sl
gmt psscale -D15.7/2.5/5/0.4 -Cmap.cpt -Bx1000f200+l"CCN" -O -S >> test.ps

Thank you