  Let $A$ be a regular 2-dimensional local ring of characteristic $p>0$, and
let $L/K$ be a cyclic extension of degree $p$ of its field of fractions such
that the corresponding branch divisor is normal crossing. For each $\gp\in\Spec
A$ of height 1 such that $A/\gp$ is regular, consider the ramification jump
$h_\gp$ of the extension of the residue field at $\gp$. In this paper the
semi-continuity of $h_\gp$ with respect to Zariski topology of suitable jet
spaces is proved. The asymptotic of $h_\gp$ with respect to intersection
multiplicity of the prime divisor defined by $\gp$ and the branch divisor is
also addressed.
