Steady conical ice cap with a linear accumulation gradient
= Steady conical ice cap with a linear accumulation gradient
For <ice accumulation> $a=A(1-x/\ell)$, regular zero flux at the apex gives
$$
h_s^3=\frac AD\left(\frac x2-\frac{x^2}{3\ell}\right),\qquad 0<x<\frac32\ell.
$$
The steady zero-thickness terminus is at $3\ell/2$, below the <snowline> $x=\ell$. Accumulation above the snowline exactly balances <ice ablation> below it.