_RL c1Frz, c2Frz, aFrz, hFrz
aFrz = (c1Frz+c2Frz)/(hThickIce-hThinIce)
hFrz = hThinIce+c2Frz/aFrz
aFrz = -1. _d 0 /(hThickIce-hThinIce)
xxFrz = aFrz*(hi-hFrz)