I'm looking to parametrize the upper surface of a portion of the sphere x^2 + y^2 + z^2 = 16 contained within the cylinder x^2+y^2 = 4y

since its a sphere, i've parametrize into spherical coordinates with

x(u,v) = (4sin(u)cos(v), 4sin(u)cos(v),4cos(u))

with v={0,2pi}

however, I'm stuck on finding the bounds for u. specifically with the cylinder being x^2+(y+1)^2 = 1, i'm unsure how to set u. i have r = 4sinv, but that doesn't seem to help. Maybe i'm going about the question wrong.