摘要
利用1978--1990年间宁夏地区5-9月的飞机云物理观测资料，重点分析了无层积云的高层云宏观和微观物理结构。研究表明：（1）无层积云的高层云云底比有层积云的高层云云底略高，云滴谱小粒子的数浓度也较大。暖层中的大云滴浓度高于冷层，可为云滴的碰并增长和冰晶繁生提供一定的大滴，利于降水的形成。（2）含水量的垂直分布具有多个峰值，极大值位于云的中下部，有利于高层冰雪晶粒子下落过程中碰并增长。（3）高层云雪晶谱总体上呈单调下降型，尺度为0．3—0．6mm的雪晶浓度达到最大，优势晶形以立体枝状、柱状和针状为主。用M—P分布N=N0exp（-λr）来拟合雪晶谱，系数N0为0．132，系数λ为2．681，相关系数，为0．975，拟合精度优于Г函数N（r）=ar2exp（-br）。
Macro and microphysical characteristics of altostratus without stratocumulus are analyzed based on dataset of airborne observations in Ningxia area from May to September between 1978 and 1990. The results show that （ 1 ） The cloud base of precipitating stratus without stratocumulus is a little higher than that with stratocumulus and the concentration of cloud droplets spectral of small particles is a little higher. The concentration of big droplets in warm layer is higher than that in cold layer, which can provide a certain big droplets for coagulation growth of cloud droplets and multiplication of ice crystals and is propitious to the formation of precipitation. （2） The vertical distribution of liquid water content has several peak values, the maximum value lies in the middle-and-lower part, which is propitious to the coagulation growth of ice and snow crystals. （3） Ice crystals spectral of altostratus assumes a monotonous fall in the mass, and the content of snow crystals reaches maximum values at the size scale of 0. 3 - 0. 6 mm. The preponderant shapes of crystals are spatial dendrite, prismatic and acicular mainly. Using M-P distribution to fit snow crystals spectral, it is found that coefficient N0is 0. 132, coefficient A is 2. 681 and related coefficient λ is 0. 975, and the fitting precision of M-P distribution is superior to the Г function N（r） = ar2exp（ - br）.
出处
《气象科学》
CSCD
北大核心
2008年第3期258-263,共6页
Journal of the Meteorological Sciences
基金
国家自然科学基金重点项目(40537034)
关键词
层状云
微物理结构
降水
Stratiform cloud Microphysical structure Precipitation
