HoloScene
Clouds play an important role in our climate system. They are responsible for the precipitation that plants, animals, and humans rely on and play a key role in the Earth’s radiation budget. The amount of precipitation produced and the amount of radiation that clouds reflect is controlled by the number, size and shape of the cloud droplets and ice crystals within them. The HOLOgraphic Sampler for investigating Cloud Evolution from Nucleation to Evaporation (HoloSCENE) measures the number and size of these cloud droplets and ice crystals in clouds. HoloSCENE does this using a well-defined light source and a high-resolution camera. The light source illuminates all of the cloud droplets and ice crystals within a 20 cm-3 volume of cloud and the camera captures their forward scattering pattern 71 times a second. The shape and size of each cloud particle in the volume is calculated from the 2-D photograph using the principles of in-line holography and then classified as either a cloud droplet or an ice crystal. As the 20 cm-3 cloud volume is captured at once, the spatial distribution of these particles is also obtained, allowing for the interactions between cloud droplets and ice crystals to be observed on a mm scale. Thus, HoloSCENE provides the unique opportunity to simultaneously observe the number, size, and spatial distribution of cloud particles.
Through the IceSafari project, a new holographic cloud probe, HoloScene, has been developed based on the design of HoloBalloon (Ramelli et al, 2020). HoloScene (see Fig. 1) is particularly well suited to count, size and identify the phase of cloud particles between 25 and 100 microns. Furthermore, through the use of holography, a much larger area of cloud is sampled relative to other methods (e.g. Cloud Imaging Probe) able to discriminate between ice and water in this size range. This gives INCAS the unique opportunity to join the handful of world-class research institutes capable of observing and quantifying secondary ice production.
A strong knowledge transfer was conducted from Norwegian partners to INCAS regarding holographic cloud investigations, and from Romanian partners to Norwegian ones regarding design, engineering and airborne certification processes. A technical visit was also carried out by two researchers from Andøya Space and University of Oslo in Bucharest from August – October 2021, with the goal of ensuring proper communication between teams, identifying and overcoming technical engineering challenges.
IceWarn
Additionally, in the near future the IceSafari project will continue the developments of a new sensor cluster, IceWarn, based on the design of Andøya Space. All test setups of IceWarn are working as expected under lab conditions. The prototype, which will be used for the first flight tests during spring 2022, is under construction.
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