Max Planck CloudKite
The CloudKite is a tethered 250m3 helium-filled balloon-kite combination aerostat (known as a Helikite), which is 15m long and 10m wide/high. The CloudKite provides the possibility of picking clouds of interests and performing measurements away from topographic effects. It is capable of lifting a net payload of 75kg when operating at an altitude of 1km above the sea level. The instrument box onboard the CloudKite is designed for simultaneous acquisition of cloud-microphysics and cloud/atmospheric turbulence. Every flight, the CloudKite holographic and Particle Image Velocimetry (PIV) modules will image 3 L/s of cloud for 35 min (about 6 m3 imaged in total) while acquiring air velocity, temperature, and humidity as well as particle size counting and 1D velocities for the whole 2-3 hour flight.
The CloudKite instrument box is carefully designed to maximize the overlap between probing volumes of various instruments. This makes it possible to fully resolve the coupling between cloud microphysics and turbulence. Furthermore, the low wind speed typically achieved by tethered aerostats combined with the high frame rate of our imaging instruments allows us to capture much smaller inter-frame-distances than those that possible by aircraft-borne instruments.
Each Cloudkite carries a suite of instruments to measure fluid properties and particle properties in clouds. But to interpret the time series of wind speed and other quantitites measured by the Cloudkite as well as evaluating flight safety, we need additional instruments on the ground to get the big picture in terms of cloud and boundary layer dynamics. Additionally, we need to transport the Cloudkite to the field, have a location to repair instruments, and bring some computing power to do data analysis in the field. To accomplish this, we are building the Mobile Cloud Laboratory (MCL), an instrumented van to transport the Cloudkite and function as a mobile weather station.
The quantities measured on the ground are basic meteorology (temperature, pressure, relative humidity, wind speed and direction), dewpoint via chilled mirror, precipitation rate, hydrometeor size distribution, cloud ceiling and backscatter, and the atmospheric electric field via field mill. Specifically, the wind and electric field measurements are important to evaluate the risk of high winds and potential lightning.
The CloudKite had its maiden field campaign over the Atlantic Ocean in April-May 2019 and it is planed to join the Eurec4A++ field campaign in Jan-Feb 2020.