  We observed that radio-frequency (rf) irradiation significantly enhances the
$c$-axis resistance near and below the superconducting transition of the
CuO$_{2}$ layer in contact with a normal-metal electrode on the surface of
Bi$_{2}$Sr$_{2}$CaCu$_{2}$O$_{8+x}$ single crystals. We attribute the
resistance anomaly to the rf-induced charge-imbalance nonequilibrium effect in
the surface CuO$_{2}$ layer. The relaxation of the charge-imbalance in this
highly anisotropic system is impeded by the slow quasiparticle recombination
rate, which results in the observed excessive resistance.
