Based on multi-channel microwave radiometer data and hourly precipitation data from Hohhot meteorological station, the monthly changes of the integrated water vapor and the integrated liquid water content in arid and semi-arid region in central Inner Mongolia on 35 precipitation days from April to September in 2017 and 2018 are studied, and the phase characteristics between the integrated water vapor and the integrated liquid water content and vertical distribution of liquid water and water vapor under steady precipitation and convective precipitation conditions are further analyzed. The results show that the integrated water vapor and the integrated liquid water content on precipitation days have obvious seasonal variation characteristics, and both are larger in summer and early autumn. Before precipitation, the integrated liquid water and the integrated water vapor increase significantly, which is even more pronounced during convective precipitation processes, and more than 80% of the samples show an anti-phase change between the integrated liquid water and the integrated water vapor. The water vapor during convective precipitation processes is mainly distributed at the height of 0-6.0 km and decreases with height, while the liquid water increases firstly and then decreases with height. The vertical distribution of water vapor and liquid water during steady precipitation processes is consistent with convective precipitation processes, but the values on each layer are less than those of convective precipitation. The precipitation occurrence judgment conditions based on integrated water vapor and integrated liquid water have practical application value for guiding local artificial rainfall enhancement operations and alleviating drought.

The analysis of cloud macro and micro physical characteristics was conductive to improve the understanding of cloud bodies and provide technical support for local scientific artificial precipitation enhancement. The microphysical characteristics of stratiform cloud were analyzed by using an aircraft detection data and sounding data in middle region of Inner Mongolia on May 10, 2018. Affected by 500 hPa upper trough and Hetao cyclone, a stable stratiform cloud precipitation occurred in middle region of Inner Mongolia. The number concentration of precipitation particles and cloud particles were small in the middle and lower part of the stratiform cloud, and the vertical and horizontal distribution of cloud microphysical parameters showed obvious heterogeneity. The cloud particle spectrum presented a single peak distribution and generally a decreasing trend. The aircraft detection data showed 63.53% of cloud water content was greater than 0.002 g·m^-3, 83.2% of super-cooled water content was greater than 0.010 g·m^-3, and the super-cooled water content ranged from 0.010 to 0.050 g·m^-3. There were areas with small natural ice crystals and relatively abundant super-cooled water in cloud with lower temperature, which had good crystal introduction and catalytic potential.

 Based on the precipitation data from automatic stations, radar echoes products, and satellite cloud images in western Inner Mongolia, a total of 49 precipitation processes in 2017 and 2018 were selected. The macro characteristics of precipitation clouds, no precipitation clouds and approaching precipitation clouds in the study region were analyzed by using the Lband sounding data, FY2 satellite inversion products and precipitation data. More than 80% samples statistical results showed that the base altitude, top altitude and cloud layer thickness of precipitation clouds were less than or equal to 3.0 km, higher than or equal to 8.0 km and higher than or equal to 6.0 km, respectively. The number of cloud interlayer was less than or equal to 2 and the thickness of cloud interlayer was less than or equal to 0.6 km, the cloud interlayer distributed sparsely. The cloud optical thickness and liquid water path had certain advantages as an index and criterion for precipitation clouds. Nearly 70% of the samples indicated that the optical thickness and the liquid water path of precipitation clouds were higher than or equal to 20 and 100 g·m-2, respectively. The general intensity precipitation was more likely to occur in areas with higher optical thickness, higher liquid water content, or optical thickness was higher than or equal to 55 and liquid water path was less than or equal to 500 g·m-2.

Based on the WRF model, a hail process was analyzed and simulated in central Inner Mongolia on 29 July 2015. The influence of cumulus and microphysics parameterization schemes on hail simulation was discussed preliminarily. The temporal changes of the mass concentration of liquid and solid precipitation particles were affected by microphysics and cumulus parameterization schemes, and water vapor and energy and dynamic conditions were mainly affected by cumulus parameterization scheme. Considering the threat score (TS) of different grades precipitation and the simulation effect of the two convective processes in Hohhot, KF scheme was better, followed by G3 and GD, and BMJ was worse in four kinds of cumulus parameterization schemes. Meanwhile Lin and WSM6 schemes were better in five kinds of microphysics parameterization schemes. WSM6-KF scheme had advantages in simulation of temporal changes of precipitation particles, water vapor and energy and dynamic conditions.