pages - The Black Vault

mechanism is used in a supplementary fashion to predict seeding-produced riseiii the top of convection and the updraft which is generated.The c,,mbin,,d models show that in the winter storm convection prevalent inthis area, the possibility of overseeding, i.e., a seeding-produced reduction inprecipitation through an oversupply of artificial nuclei, is possible in verycold systems. The dynamically-produced rise in cloud top may increase the chanc,.of ti\erseeding with many small ice crystals being ejected from thiý top ofrinure 3 isan exampl- of the predicted area of effect for a hypotheticalcas.. ThL quadrilateral enclosed by the solid lines and marked primary area ofe-ffekct represenz s the envelope of possible fallout trajectory enipoints (groundintelrception).The dashed line represents the limits of the ground Plume.Diffusiot; w-ithin the ground plune isassumed to follow the type of plumewhich observations< and laboratoiy modeling indicate occurs inthe rugged terrain,ronldl Climax, Colorado (Orgill, 1971). The plume expands vertically and horizontall'!qunit- ratpidly in th:e fir'st 5 knm, and at a lesser ralte, thereafter. First,litomillellnit into conIvection is assumed to occur at 500 sec plum(- travel distanct,toit I'ron the sourcu. The farthest-out entrainment is assumed to occur at a dis--tance which smoke particles from the firsttht, trailiar ed.-c of the band passed by the source.Inflare could have reached at the timeýome im-tanceS the ground plume top rose sufficiently high for iudillgto occur within it. This is shown by the hatched area within the plume houndariesin this hvpothetical case.The closefat-in falout lfrom con'rection (usually the largest and ,arlie.-tnucle.ated particle:-) i• calculated to reach the ground at puint: 1 from the firstpous-.ible convection tower and at point 2 from the last poss ible tower. Comlpntatio,•nfor more towe2-:s show that the straight line drawn lietw,,(I 1 and 2 is o fairapproximation of the calculated upwind limit of the effect.fa;llout from con-,.ction (usunlly thi.The farthest-outp;.rticles falling from ricar convection top)mite '.-et the groun' al po.uition 3 ( fi rst tower) an,. posil ion 4 (last ltowr).Thi. irea is des ivgnated the pima., ill'ayar.Ra'dar dati inldiclte lhat colný.ct jti in the .e syst: m .kaM_ iI me,' (, pjteip, itj tip/itt,.ru as•oc i~i,,.d with it 1>,. about "0° to the rig•hf_ oIt htpe wmc;11 .ind dir necin,•,etee th•,',.iil top ol .',,viection and at aboutl ha;ltf i,- speýd. Thison-7-