Laserfiche WebLink
<br />The mesoscale research is focused on t"~o objectives. The first is to <br />describe the boundary-layer characteristics, including (1) the manner in which <br />convective expansion is reflected in surface convergence and vorticity fields, <br />(2) the changes in precipitation efficiency as the cloud system expands from <br />an isolated tower into a multicelled mass of convective elements, (3) the <br />nature of the interaction between new clouds and the parent system, and (4) <br />the environmental conditions under which such interaction works constructively <br />on a developing system and those conditions under which interaction acts <br />destructively. <br /> <br />The second objective is to determine the extent of change in <br />precipitation efficiency as convection becomes organized with linear <br />structures approaching 100 km, and the effects of such linear organization on <br />the flux of moisture through a fixed boundary surrounding the line. Changes <br />in the area-wide precipitation efficiency may prove to be the most sensitive <br />measure of seeding effectiveness. Accurate measurement of the movement of <br />moisture through the area boundaries within the sub-cloud layer should relate <br />it to sub-synoptic-scale convective activity. <br /> <br />The heart of the CDMP operational design is expected to be a nested grid <br />of surface-based meteorological instrumentation that can collect wind, <br />temperature, humidity, pressure, and rainfall information on various scales of <br />motion. Remote-sensing devices (Doppler radars, lidars, etc.) will be used to <br />obtain cloud-scale and mesoscale data bearing on the problem of cloud <br />organization. In situ aircraft measurements will also play an important role <br />in the CDMP. The program design will likely be planned around one or b10 <br />high-performance aircraft capable of penetrating rising convective towers in a <br />Lagrangian sense. Another aircraft will be used in low-altitude studies of <br />cloud-scale and mesoscale boundary layer fluxes and convergence profiles. A <br />mix of conventional instrumentation (rawinsondes and pibals) and new proven <br />remote microwave sensing techniques is anticipated to study the the~dynamic <br />and fair-weather structure of the sub-cloud layer. <br /> <br />CDMP will be planned and des igned in FY 1981. Preliminary tes ti08 of <br />field systems and hypotheses will be done in cooperation with CCOPE in <br />Montana, simultaneously broadening both the observing base or CCOPE and the <br />test data base of CDMP. <br /> <br />A 10-Meek field program will be conducted in Florida during ~{ 1983. <br />Data processing, data analysis, and interpretation or the results or the <br />Florida Experiment will occur in FY 1984 and 1985 period. Critical design <br />features will be restructured and a second field experiment in FY 1986 will be <br />planned in FY 1984 and FY 1985. The location of the second field project is <br />not yet specified. Data will be analyzed and experimental results will be <br />interpreted in FY 1987-1989. It is anticipated that critical physical <br />linkages related to cumulus modification will have been documented to the <br />extent that any beneficial technology generated can be transferr~d to user <br />groups. A third field program may be required in FY 1990 to address remaining <br />road-blocks to development of a viable modification technology for convective <br />cl ouds . <br /> <br />- 35 - <br />