Dust- versus cloud-radiation impacts on the diurnal temperature range for long-lasting dust weather over the Taklimakan Desert

Abstract

The diurnal temperature range (DTR), determined by the difference between daily maximum and minimum air temperature, is an important index of global climate change. The dust direct radiative effect on DTR in cloudy conditions in the Taklimakan Desert (TD) area is still unclear. Based on springtime ground observation data from 2002 to 2013, the DTR variation in dust/cloudy days and the DTR-visibility relationship in dust days in TD were analyzed and summarized. The mean DTR was proportional to the mean visibility, with a slow DTR increase in the southwestern TD caused by cloud-induced radiation when visibility was 4–10 km; the DTR difference between cloudy and cloudless dust days was more significant (1.8–4.2 °C) when visibility was >6 km. The simulation of a long-lasting dust-cloud coexisting event (4 days) with the factor separation technique showed that both pure dust- and cloud-radiation impacts reduced DTR but their synergistic radiation impact mostly increased DTR in TD. Both simulated and observed results indicated that when the daily visibility of dust weather increased from 4-6 km to 6–10 km, the important pure dust impact on DTR weakened whereas the cloud impact became significant.