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 IDEAS-4 GV 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.

三视场云粒子成像仪（Three-View Cloud Particle Imager，3V-CPI）是三台成像仪器的组合体。其中两台构成2D-S型仪器：该仪器搭载两台二维探头，当粒子穿过与气流及彼此均正交的光束时，探头可对其成像。若粒子同时处于两束光束的敏感区域交集内，则两台二维探头均可捕捉到该粒子。此时3V-CPI将触发拍摄高分辨率图像：通过短时照明的高分辨率成像阵列，获取第三幅高分辨率影像。
该仪器尤其适用于冰晶成像，同时也可有效探测各类水凝物，包括大云滴、毛毛雨、小雨滴及降水粒子。3V-CPI可测量云内粒径范围为15~250微米的水滴与冰粒子的尺寸、形状及浓度。
本数据集包含IDEAS-4 GV项目期间，搭载于美国国家大气研究中心（NCAR）GV（HIAPER）高空研究飞机的3V-CPI采集的感兴趣区域（Region of Interest，ROI）图像。在所有飞行任务中，3V-CPI会按需生成若干*.roi格式文件；单文件最大容量为92兆字节，达到上限后将自动创建新文件。