Falling probes to monitor precipitations

A feasibility analysis of a set of disposable probes for sensing the cloud environment will be presented. The very light probes, dropped by a plane or a UAV above the clouds, are designed to dynamically behave in their falling through the atmosphere as drops/hailstones in order to follow the wind and the turbulence affecting the drops themselves. In order to realize sensing probes with a similar fluid-dynamic behavior of drops and hailstone, the weight, the size and the surface properties of the probes should be carefully designed: we estimate sizes of the order of a few centimeter and a total weight of less than 15 g. Consequently, the electronic boards, sensors, and transmitters have to remain very light with a minimum power consumption to guarantee good measurements and data transmission during the falling time (about 20 minutes). During their falling to the ground, the sensors installed in the probe will measure directly different parameters such as humidity, temperature, pressure, acceleration with a sampling interval of 10ms. All data are sent to a receiver located on the ground according to a specific temporal interval (e.g. 1 seconds) and a polling techniques is implemented. A specific analysis of the propagation channel is performed, in order to assure the possibility of a robust communication link between probes and the ground receiver. The probes can be used for efficient monitoring operations of precipitation dynamics and drops/hail stones formation conditions.