Diurnal and seasonal variation of the elevation gradient of air temperature in the northern flank of the western Qinling Mountain range,China

The typically sparse or lacking distribution of meteorological stations in mountainous areas inadequately resolves temperature elevation variability. This study presented the diurnal and seasonal variations of the elevation gradient of air temperature in the northern flank of the western Qinling Mountain range,which has not been thoroughly evaluated. The measurements were conducted at 9 different elevations between 1710 and 2500 m from August 2014 to August 2015 with HOBO Data loggers. The results showed that the annual temperature lapse rates（TLRs） for Tmean,Tmin and Tmax were 0.45？C/100 m,0.44？C/100 m and 0.40？C/100 m,respectively,which are substantially smaller than the often used value of 0.60°C/100 m to 0.65°C/100 m. The TLRs showed no obvious seasonal variations,except for the maximum temperature lapse rate,which was steeper in winter and shallower in spring. Additionally,the TLRs showed significant diurnal variations,with the steepest TLR in forenoon and the shallowest in early morning or late-afternoon,and the TLRs changed more severely during the daytime than night time. The accumulated temperature above 0°C,5°C and 10°C（AT0,AT5 and AT10） decreased at a lapse rate of 112.8？C days/100 m,104.5？C days/100 m and 137.0？C days/100 m,respectively. The monthly and annual mean diurnal range of temperatures（MDRT and ADRT） demonstrated unimodal curves along the elevation gradients,while the annual range of temperature（ART） showed no significant elevation differences. Our results strongly suggest that the extrapolated regional TLR may not be a good representative for an individual mountainside,in particular,where there are only sparse meteorological stations at high elevations.