Plot3D[1+Sqrt[x^2+y^2],{x,-2,2},{y,-2,2}];
Spherical Coordinates do quite nicely here.
x=x(u,v)=a cos u sin v
y=y(u,v)=a sin u sin v
z=z(u,v)=a cos v
u from 0 to 2Pi
v from 0 to Pi
I hope you can see this is (cos u sin v, sin u sin v, 1+sin v).
ParametricPlot3D[{Cos[u] Sin[v], Sin[u] Sin[v], 1+Sin[v]},{u,0,2 Pi},{v,0,Pi}];Up to z=S(x, y) or R=R(u, v) ?