Elevational ground/air thermal gradients in the Swiss inner Alpine Valais

The dependence of air temperature on elevation (i.e., its elevational gradient) in the mountains is well known. However, the elevational gradient of near-surface ground temperatures and derived thermal parameters is much less understood. In this study, we investigated how these parameters depend on elevation by one-year temperature measurements along a transect in the Valais Alps (Switzerland) between 700 and 2,600 m a.s.l. In addition, we studied the effect of differences in slope aspect (north/south) and land cover (open field/forest). Air temperatures were measured as a reference. The results show that the ground thermal regime distinctly differs from that of the air. These differences could mainly be attributed to radiation, snow cover, and ground heat transfer. Our findings have far-reaching implications for ecosystems, agriculture, and forestry in mountains because a large portion of the living biomass is underground and thus affected by ground thermal processes.