From The Collaborative International Dictionary of English v.0.48 :
downslope \downslope\ n. a downward slope. Syn: descent, declivity, fall, decline. [WordNet 1.5]From WordNet (r) 3.0 (2006) :
downslope n 1: a downward slope or bend [syn: descent, declivity, fall, decline, declination, declension, downslope] [ant: acclivity, ascent, climb, raise, rise, upgrade]