Laserfiche WebLink
<br />AIRCRAFT INSTRUMENTATION FOR CLOUD PHYSICS RESEARCH <br />AND WEATHER l'1ODIFlCATION PROGRAMMES <br /> <br />Gabor VaU <br /> <br />Department of Atmospheric Science <br />University of Wyoming <br />laramie, Wyoming, U.S.A. <br /> <br />ABSTRACT <br /> <br />The lecture drew heavily on previous PEP documents for definition of the pur- <br />poses of aircraft observations; this material is not reproduced in full here. <br /> <br />Any weather modification programme should be based on a knowledge and understand- <br />ing of the natural cloud physics processes taking place in the clouds to be modified. <br />Observations of clouds can be obtained in many ways (e.3. visual, radar, weather <br />satellite, etc.) which are mostly indirect, but the key observations of cloud micro- <br />physical structure can be obtained only by direct in-situ measurements using instrumented <br />aircraft. <br /> <br />The most important measurements required in relation to precipitation enhancement <br />programmes are indicated in the PEP Design Document (PEP Report No.9) as follows: <br /> <br />cloud water content; cloud droplet size distribution; cloud <br />nucleus spectrum; spectrum of large hygroscopic particles; ice <br />particle content; ice nucleus spectrum; cloud temperature and <br />buoyancy; updraft structure. <br /> <br />There is a wide diversity of in~;trumentation and aircraft types that can be used <br />to obtain the above measurements. These are comprehensively reviewed, with advantages <br />and disadvantages, in PEP Report No. 7 - Aircraft Instrumentation for Cloud Physics <br />Research and Weather Modification ProlJramme:s. In addition to the selection of the <br />most suitable instrumentation and aircraft for a given project, special attention <br />must be paid to the mounting of the instruments on the aircraft, their maintenance <br />and calibration and the data recordinlJ. <br /> <br />The acquisition of valid in-situ measurements requires that the sensors be <br />appropriately mounted on the aircraft. The requirements vary with what is being <br />measured and with the design of the instrument, and these requirements must be <br />carefully examined and reconciled with the flow perturbations which the aircraft causes. <br />