NSF/NCAR GV (HIAPER) 3V-CPI Raw CPI ROI Imagery. Version 1.0

The Three-View Cloud Particle Imager (3V-CPI) is a combination of three imaging instruments. Two of them comprise a 2D-S instrument, in which two 2D probes image particles as they pass through beams that are oriented orthogonally to each other and the airflow. If particles also lie in the intersection of the sensitive areas of the two beams, they are seen by both 2D probes. In that case, the CPI is triggered to take a high-resolution picture, via a briefly illuminated high-resolution imaging array, to provide a third image at high resolution. The probe is particularly suited to imaging ice crystals, but also provide good detection of other hydrometeors including large cloud droplets, drizzle and small rain drops, and precipitation particles. The 3V-CPI measures the size, shape and concentration of water drops and ice particles in clouds in the size range of 15-250 µm. This dataset contains CPI roi images collected by the 3V-CPI aboard the NCAR GV (HIAPER) during the DC3 project. For all of the flights, the CPI makes as many *.roi files as it needs; each file can be maximum 92Mb size and then a new file is opened.

三维云粒子成像仪（Three-View Cloud Particle Imager，3V-CPI）是三台成像仪器的组合体。其中两台组成2D-S仪器（2D-S instrument）：当粒子穿过彼此正交且与气流方向垂直的光束时，两台二维探头分别对粒子进行成像。若粒子同时位于两束光束的敏感区域交点，则两台二维探头均可捕捉到该粒子。此时CPI将触发高分辨率成像阵列，通过短时照明获取高分辨率图像，以此生成第三维成像结果。该仪器尤其适配冰晶的成像观测，同时可有效探测各类水成物，包括大云滴、毛毛雨、小雨滴及降水粒子。
3V-CPI可测量尺寸范围为15~250微米的云内水滴与冰粒子的大小、形态及数浓度。
本数据集包含由搭载于美国国家大气研究中心（National Center for Atmospheric Research，NCAR）GV（HIAPER）研究机的3V-CPI在DC3项目期间采集的CPI感兴趣区域（Region of Interest，roi）图像。在全部飞行任务中，CPI将按需生成*.roi格式文件，单文件最大容量为92兆字节，达到上限后将自动开启新文件。