Effects of a 100-fold increase in irradiation with Model Irrad100 (top) and the reverse grain temperature trend with Model Tpow1/6 (bottom) on ice loss and re-accumulation. Left: ice thickness (black lines) changes with T_d (red). The thicker lines show larger grains. Right: ice (solid lines) and gas-phase (dotted lines) abundances of the major ice species relative to H₂. This is to be compared with Model Standard in Fig. 2.