_RL c1Mlt, c2Mlt, aMlt, hMlt
aMlt = (c1Mlt+c2Mlt)/(hThickIce-hThinIce)
hMlt = hThinIce+c2Mlt/aMlt
aMlt = -1. _d 0 /(hThickIce-hThinIce)
xxMlt = aMlt*(hi-hMlt)