Changes in sunshine duration are correlated with changes in daily temperature range this century: An analysis of Swiss climatological data

Analyses of the relationship between trends in daily temperature range and those of sunshine duration in the Swiss Alps show a strong correlation at lower elevation sites. The decrease in daily temperature range is associated with a corresponding decrease in sunshine duration. At high elevations, however, this relationship is absent. The decrease in daily temperature range observed this century at lower elevation sites is inferred to be a consequence of an increase in low‐level cloudiness. Higher elevation sites lie above the low‐level cloud layers and the moisture‐laden lower atmospheric boundary layer and as a result do not exhibit the same trends.