2014年青藏高原云和降水多种雷达综合观测试验及云特征初步分析结果

The preliminary analyses of the cloud properties over the Tibetan Plateau from the field experiments in clouds precipitation with the vavious radars

  • 摘要: 加密外场试验可提供云降水物理过程新的数据。2014年7月1日—8月31日,第3次青藏高原大气科学试验项目组在那曲开展了水汽、云和降水的综合观测,使用了中国最先进的Ka波段毫米波云雷达、Ku波段微降水雷达、C波段连续波雷达和激光雷达,并配以微波辐射计、雨滴谱仪等设备,获取了高时空分辨率的云和降水宏微观垂直结构特征数据;利用C波段双线偏振雷达与新一代天气雷达配对,进行双多普勒雷达观测,获取青藏高原对流云三维风场和降水粒子相态的结构和演变数据。文中简单介绍了本次试验的情况,并利用这次观测的云雷达数据对那曲地区夏季云的云顶和云底高度、云厚、云量、云层数等特征的日变化进行了初步统计分析,对不同类型云的宏观特征进行了讨论。结果表明:本次外场试验首次成功获取到了多种雷达的云观测数据。那曲地区夏季云主要集中在6 km(距地面高度,下同)以上和4 km以下;总云量、高云的云顶、云量和云厚等云的统计参数有明显的日变化,10时(北京时)为云发展最弱的时段,20时云发展最为旺盛;初生的积云和层云常常出现在3 km高度上,这一高度上常常存在明显的上升气流;深对流系统高度可达16.5 km,同时存在上升气流和下沉气流,对流中可能存在过冷水。这些数据和初步结果为进一步开展高原云和降水机理、云和降水物理过程参数化方案研究及卫星反演结果的订正提供了基础。

     

    Abstract: It is well realized that the intensive field experiment in cloud and precipitation provides significant information for the microphysical and dynamic processes. In the project of the Third Tibetan Plateau Experiment of Atmospheric Sciences, the intensive observation of cloud and precipitation in Naqu was conducted from July 1 to August 31, 2014. The advanced radars, such as Ka band cloud radar, Ku band micro-rain radar, C band frequency modulation and persistent wave (FMCW) radar, Lidar, disdrometers and microwave radiometer were used to observe the vertical structures of cloud physics, and, the C band mobile polarization radar and C band operational Doppler radar formed a dual-Doppler system to observe the 3-D wind field and hydrometeor phase. In this paper, the field experiment was introduced and the radar data were used to analyze the daily variations of the cloud properties (including cloud top and base, cloud amount, physical thickness, layers and vertical distribution) and the cloud cases for the different type cloud processes. The results show that most of the clouds were located above 6 km and below 4 km above the ground level.The cloud top and base, cloud amount and thickness for the clouds above 6 km had obvious daily variations. The cloud processes were the strongest at 20:00 Beijing time (BT) and the weakest at 08:00 BT. The initial cloud often developed at 3 km above the ground level with upper draft in this level. The deep convective cloud could develop to 16.5 km above the ground level, the strong upper draft and down draft were observed. The supercooled water possibly existed in the deep convective cloud. The data observed in the field experiment and preliminary results will be used in the studies of cloud physics, the cloud and precipitation process parameterization, and the correction of retrieved productions from satellite.

     

/

返回文章
返回