It has long been suggested that aircraft flying through supercooled clouds might cause the formation of ice particles. Recent observations of these Aircraft Produced Ice Particles (APIPs) have indicated that the effect might be quite pronounced. The magnitude of the APIPs phenomenon and the conditions under which it occurs is of importance in interpreting the results from previous experiments which used research aircraft and in planning future projects. The Principal Investigators propose a field experiment to test the hypothesis that APIPs are caused by aerodynamic cooling in the vortices created behind propeller and wing tips. The experimental sight will be near Mono Lake, California which is known for frequent and stable supercooled fogs in the wintertime. The Principal Investigators will use a range of aircraft in this "natural laboratory" to produce APIPs while quantitatively sampling the resultant ice particles using a state of the art research aircraft.
