Aircraft observations were conducted over the eastern mountainous areas of the United Arab Emirates (UAE) in September 2017 to characterize the microphysical properties of diurnal convective clouds. Aerosol particle and cloud condensation nuclei (CCN) measurements indicate that the air mass had a continental nature, resulting in high cloud droplet concentrations of 600-800 cm⁻³. Two case studies were undertaken to obtain the vertical profiles of hydrometeors up to the cloud top. The ice particle number concentrations in the updraft core were a few particles L⁻¹, which is similar to the primary ice nucleating particle (INP) number concentrations estimated from immersion freezing of high concentration dust particles in the convectively mixed boundary layer. The ice particle number concentrations were several tens of particles L⁻¹ outside the updraft core in the upper levels. INP measurements and the observed cloud microphysical structure suggest that drizzles, frozen via the immersion freezing nucleation of dust particles, formed graupel embryos and ice particles, with concentrations of one to two orders of magnitude greater than those of the primary INPs, which may be generated via secondary ice production and/or ice particle accumulation from primary ice nucleation in clouds with relatively warm cloud top temperatures (approximately −12°C).

2017年9月在阿拉伯联合酋长国（UAE）东部山区进行了飞机观测，以表征日对流云的微物理特性。气溶胶颗粒和云凝结核（CCN）的测量表明，气团具有大陆性，导致600-800 cm ^-3的高云滴浓度。进行了两个案例研究，以获取直到云顶的水凝物的垂直剖面。上升气流核心中的冰粒数浓度为几粒L ^-1，这类似于通过对流混合边界层中的高浓度尘埃颗粒的浸没冷冻估计的一次冰成核颗粒（INP）数量浓度。冰粒数浓度是高层中上升气流核心外部数十个粒子L ^-1。INP测量和观察到的云微物理结构表明，细雨通过尘埃颗粒的浸没式冷冻成核而冻结，形成了gra胚和冰粒，其浓度比主要INP的浓度高一到两个数量级。通过次级冰的产生和/或初级冰成核在高云顶温度（约-12°C）的云中积累冰粒。