Effects of radiative forcing on stable boundary layer development and diurnal temperature range over the central Heihe River Basin, China

Abstract

Using observations from the Heihe Watershed Allied Telemetry Experimental Research (HiWATER) datasets, the effect of radiative forcing on the development of the stable boundary layer (SBL) and diurnal temperature range (DTR) during summer over the central Heihe River Basin is investigated in this paper. Using a radiative temperature scale based on net longwave radiation (LW net24), the DTR and the strength of SBL (δT S) are scaled, and the cycle and the year-to-year variability before and after scaling are analyzed. The results show that both DTR from air and surface temperatures have a significant correlation with LW net24 , and their correlation coefficients are different over different underlying surfaces. The cycle of DTR from 5-m air temperature is similar with that of LW net24. There is only a diurnal cycle in terms of 5-m air temperature after scaling. Both the trends of the scaled DTR (DTR sc) and the scaled strength of SBL (δT Ssc) increase with the growth time of the stable boundary layer (SBL) (τ S). The period of τ S is similar with that of DTR sc. τ S is longer at the oasis site than at the Gobi site, which is related to the oasis effect. In addition, the greater the friction velocity, the smaller the DTR sc and δT Ssc. The wind shear enables heat to disperse during SBL.