Hebei Province, Aircraft Observations Of The Microphysical Structure Of Stratiform Precipitation System

Based on the PMS data obtained in 4 cases during 25,May 1991,a returning process and 20-21, June 1992,a westerly trough system,meanwhile with some radar , sounding and rainfall data,considering prior results,the microphysical structure of precipitating stratiform clouds in Hebei Province is studied from a new angle. The analysis of the PMS data obtained along level flying routes is enlianced. The microphysical structure of some mesoscale organizations in the stratiform clouds, for example, cloud bands and convective bubbles, is stressly studied. The seeding condition criteria and operation indexes in cold stratiform clouds proposed by Tao Shuwang,et al are used to justice the clouds. The variation of the temperature in the clouds , for example the inversion inside the clouds.is analysed.The main results show: the precipitating stratiform clouds in returning process are inhomogeneous, the strong precipitating cloud bands staying in them. The strong precipitating cloud bands correspond with the ground rainfall well. When the aircraft flies into the bands, the main cloud physical parameters (LWC, N, D and T, et al) changes strongly. The liquid water content (LWC) leap up, the particle concentration (N) grow up rapidly, the spectrum width become wider, the temperature descends.et al. In a same cloud band, the variation of temperature is small meanwhile the temperature is lower.The convective bubbles were observed in the warm clouds under the middle of the cumulostratus on 21,June 1992. The bubbles clearly show that they are one kind of mesoscale organization. It suggests that the synoptic system is situable to produce convective bubbles. It's contrastly analysed that the particle concentration and the liquid water content are higher.the particle spectra is similar,the particles captured by 2D-C probe are bigger in the bubbles.Inside bubbles the particle spectra is uniform distribution.In the cold clouds of 2 cases on 20,June 1992, vertical distribution of ice size, ice water content(IWC), ice concentration and LWC shows that the ice size increases with decreasing altitude, the most fast increase appears at 3400 (-1.5℃) ~3100m (0℃) where the temperature is higer and the ice particle is easer to accumulate and conglutinate which is the main cold growing process. The maximum ice concentration appears at 4400m (408/L) . The maximum LWC appears at 4000m (0.0802/m~3) .The LWC corresponding to bigger ice concentration is smaller, it is suggest that more supercooled water is consumed.The strong inversion inside clouds is detected twice at about 2000m during up and down on 25,May 1991, the LWC reaches a pea below the top of the inversion. It is...