Collaborative Research: Development of a Combined in Situ Particle Imaging Velocimeter /Fluorescence Imaging System

PIS建议建立一个新系统，对多个波长的荧光和散射光进行成像，并进行立体粒子图像测速(3D PIV)测量。这些数据将能够生成流体流动的地图和派生的量，如应变率、涡度和湍流动能的耗散率。测量将在相同的尺度上进行(20x20x0.6厘米，分辨率100um)，几乎同时进行，从而能够原位绘制生物分布与微尺度物理流动的3D图。有人提出，多个成像波长将允许对荧光颗粒进行一定程度的分类区分，而侧向散射光将提供散射激发辐射的所有颗粒的图像，包括荧光图像中出现的大多数浮游植物以及浮游动物。3D PIV多光谱成像荧光仪将安装在自由落体平台上，配备一套辅助仪器和一个水样采样器，用于成像地面实况，该采样器已经建成，并被证明可以提供水柱中浮游生物的不受干扰的景象。图像将在平台下方延伸的平面中捕获，以获得不受平台影响的分布。船上的荧光显微镜将被用来识别图像中的优势生物。由于缺乏技术，浮游生物的微尺度分布与海洋中微尺度物理动力学的关系在很大程度上受到了限制。多波长成像和PIV的结合将允许现场调查荧光颗粒/总体荧光关系、浮游生物与微尺度流动的微尺度分布、食草动物和初级生产者的空间关系，以及精细和微尺度生物斑块的物理机制。该仪器是PIS开发的现有2D成像荧光仪的改进，它只有一个传感波长，不能在与荧光图像相同的尺度上同时收集物理数据。

The PIs propose to build a new system that will image multiple wavelengths of fluoresced and scattered light and perform stereo particle image velocimetry (3D PIV) measurements. These data will enable maps of fluid flow and derived quantities such as strain rate, vorticity, and the dissipation rate of turbulent kinetic energy to be produced. Measurements will be made on identical scales (20 x 20 x 0.6 cm with 100 um resolution), nearly simultaneously, allowing in situ 3D mapping of biological distributions to microscale physical flows. It is proposed that the multiple imaging wavelengths will allow a degree of taxonomic discrimination among fluorescent particles, while the side-scattered light will provide images of all particles that scatter the excitation irradiance including most of the phytoplankton appearing in the fluorescence images, as well as zooplankton. The 3D PIV-multispectral imaging fluorometer will be mounted on a free-falling platform with a suite of auxiliary instruments and a water sampler for image ground-truthing that has already been constructed and shown to provide undisturbed views of plankton in the water column. Images will be captured in a plane extending below the platform to obtain distributions unaffected by the platform. Shipboard epifluorescence microscopy will be used to identify dominant organisms in the images.Relating microscale distributions of plankton to microscale physical dynamics in the ocean has been largely limited by a lack of technology. The combination of multiple-wavelength imaging and PIV will allow in situ investigations of fluorescent particle/bulk fluorescence relationships, microscale distributions of plankton in relation to microscale flows, spatial relationships of grazers and primary producers, and physical mechanisms underlying fine- and microscale biological patchiness. This instrument is an enhancement of an existing 2D imaging fluorometer developed by the PIs that has only one sensing wavelength, and does not gather simultaneous physical data on the same scales as the fluorescence images.