Laserfiche WebLink
<br />The airflow in the deep stable orographic clouds contains <br /> <br /> <br />a barrier jet. The barrier results when a stable air mass <br /> <br /> <br />impinges on to a mountain barrier. This phenomenon has been <br />observed and numerically simulated. <br />The shallow orographic cloud types appear to develop <br />during the mature to dissipation stages of storms when the <br />baroclinic or frontal zone shears off, generally near the 700 <br />mb level. A shallow storm cloud is left behind. The blocking <br />by the mountain barrier in conjunction with the barrier jet <br />seems to accentuate this process upwind of the Sierra barrier. <br />Within the shallow orographic cloud the warm cloud <br />coalescence process is often present. <br />Dave Reynolds discussed the randomized Floating Target and <br />Fixed Target experiments presently being conducted within the <br />shallow orographic clouds. The Floating Target experiment is <br />conducted in convective clouds and was initiated in SCPP/84. <br />The Fixed Target experiment is conducted in stratiform clouds <br />and was initiated in SCPP/85. Prior to both these randomized <br />experiments a number of preliminary seeding experiments were <br />conducted. In each experiment the seedability is established <br />prior to seeding using an instrumented cloud-physics aircraft <br />and microwave radiometer. Following seeding the evolution of <br />the seeding effect is documented in a step-by-step process <br />using first the instrumented aircraft, then radar and fianally <br />surface precipitation gages and surface hydrometeor probes. <br /> <br />3 <br />