Abstract. Cirrus clouds are located at the upper middle-lower troposphere and play an important role in the Earth's energy balance and the atmospheric water cycle. This study utilizes DARDAR-Nice data within June to August from 2006 to 2016 (except 2011), combined with CloudSat cloud products and other related aerosol products, to analyze the distribution characteristics and formation mechanisms of ice crystal number concentration (Ni) in cirrus clouds over the Tibetan Plateau (TP). The results indicate that Ni over the northern TP is significantly lower than that over the southern region, mainly due to differences in underlying aerosol concentration and the intensity of convective activity. Dominated by homogeneous nucleation, Ni exhibits a typical ‘V’ shaped vertical profile over the TP. When deep convective activity occurs, it facilitates the increase in Ni. In contrast, dust and smoke aerosols hinder the formation of Ni through heterogeneous nucleation.. Additionally, the vertical wind velocity near 400 hPa in the northern TP approaches zero, causing the Ni peak to appear prematurely below the homogeneous nucleation threshold temperature (-38 °C).
Wang et al. (Wed,) studied this question.