摘要
利用安徽寿县W-Band云雷达(95GHz,波长3.16mm)、地面微波辐射计、探空和地面观测等资料,对2008年11月5-7日一次冷锋云系的云结构进行了分析。结果表明,云雷达的多普勒速度可以初步确定粒子相态和大小以及是否存在雪晶或雨滴;在0℃层附近有回波暗带产生,这主要是由于波长为3mm的雷达对雪晶的衰减较强以及粒子的非Rayleigh散射引起的;云雷达观测可以清楚地识别混合云中的融化层。冷锋云系发展、演变过程及结构非常不均匀:锋面前部,在5～7km之间有一水凝物含量大值区,不断有长大的冰雪晶下落,使云底逐渐下伸,触地后产生间歇性阵性降水;降水过后,5km左右有一相对干层,上部为高层云,下部为散乱的多层云结构;冷锋临近,云层冷区没有水凝物含量大值区,回波强度较弱,暖区2km以下是干冷的东北气流,限制了雨滴通过暖雨过程增长,导致锋面降水强度较小,持续时间短。锋面后部4～7km高度,由于冰雪晶沉降,相对湿度较小,云层分裂成两层云;冷锋过后,出现了较强的降水,这主要是由暖雨过程产生的。
The cloud structure of a cold front on November 5-7, 2008 is hensive observed data from ARM project in Shouxian, Anhui Province, includi analyzed using the compre- ng cloud radar, ground mi- crowave radiometer, sounding and ground observation data. The results show that the particle＇s morphol- ogy and size can be preliminarily determined through the Doppler radar speed of cloud and whether or not it presence snow crystals or rain. Near 0℃ level there is a clark band, which is caused by the 3 mm wave- lehgth radar to strong attenuation of the snow crystals and the Rayleigh scattering; cloud radar observation can identify clearly melt layer. It is found that the cloud structure is very uneven, there is a hydrometeor content big value area between 5-7 km. In this area, grown snow and ice crystal fall continuously to lead to the cloud base gradually stretched downward and produce an intermittent precipitation. Below 2 km a- bove the warm area there is＇dry and cold northeast airflow, which limit the raindrop growth through the warm rain process, the precipitation intensity of front surface is caused to be small. The posterior between 4-7 km heights, because the snow and ice crystal settlement, the relative humidity is small, the clouds are split into two-layer-clouds. There is severe precipitation after the cold front, which is caused mainly by the warm rain process.
出处
《高原气象》
CSCD
北大核心
2012年第4期1129-1138,共10页
Plateau Meteorology
基金
中国气象局云雾物理环境重点开放实验室开放科研课题(2009Z00311)资助
