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<br />498
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<br />JOURNAL OF APPLIED METEOROLOGY
<br />
<br />VOLUME 17
<br />
<br />Computer Processing of Digital Radar Data Gathered during ffiPLEX
<br />
<br />MELVIN J. SCHROEDER
<br />Department of Aviation, University of North Dakota, Grand Forks 58201
<br />
<br />GERARD E. KLAZURA
<br />Division of Atmospheric Water Resources Management, Bureau of Reclamation, Denver, Colo. 80225
<br />(Manuscript received 24 June 197'7, in final form 4 January 1978)
<br />
<br />ABSTRACT
<br />
<br />Digital radar data are being collected as part of the Bureau of Reclamation's High Plains Cooperative
<br />Program (HIPLEX). The radars used in this study are sensitive, narrow-beam, 5 cm' wavelength systems
<br />which record echo data on computer compatible magnetic tape. The antenna scans continuously in a volume
<br />mode of 3600 in azimuth and 120 in elevation. The time interval for a complete volume scan is approxi-
<br />mately 5 min. An overview of the HIPLEX radar operational program and data flow from colll~ction to
<br />. analysis products is presented.
<br />Computer programs to edit, correct, compress, process and archive the data have been developed and
<br />tested. Examples and descriptions of printed, microfiche and magnetic tape output are described. These
<br />include composite maximum reflectivity and echo top displays, an equivalent reflectivity file, and a case
<br />study summary file which contains location, area, volume, rain and motion information for cells that were
<br />identified and tracked. It is shown that the flow of digital radar data has a sufficient amount of human
<br />intervention to maintain quality control in an evolving computer environment.
<br />
<br />1. Introduction
<br />
<br />The purpose of this paper is to describe the High
<br />Plains' Cooperative Program (HIPLEX) radar equip-
<br />ment, data management and analysis procedures. A
<br />primary intention is to provide an overview of the
<br />HIPLEX radar program and give a synopsis of the
<br />data flow from field collection to analysis products,
<br />describing in some detail the initial analysis and final
<br />processing outputs. The "composite B-scan," which is
<br />produced in order to delineate precipitation celb, is
<br />also discussed in detail.
<br />HIPLEX is part of the Bureau of Reclamation's
<br />Project Skywater, which has the overall goal of develop-
<br />ing an effective weather modification technology for
<br />precipitation management scientifically and socially
<br />acceptable to provide a portion of the nation's required
<br />fresh water. Miles City, Mont. , Colby-Goodland, Kans.,
<br />and Big Spring-Snyder, Tex., represent the northern,
<br />central and southern High Plains experimental areas,
<br />respectively.
<br />An improved physical understanding of natural
<br />precipitation processes must precede the final design
<br />for testing procedures. Radar, being a remote seIlsor
<br />that produces measurements which provide good tem-
<br />poral and spatial coverage of cloud structures and pre-
<br />cipitation over large areas, has been selected as one of
<br />the principal sensors for gathering information on pre-
<br />
<br />0021-8952/78/0498-0507$05.00
<br />@ 1978 American Meteorological Society
<br />
<br />cipitation processes caused by natural and augmenting
<br />mechanisms.
<br />
<br />2. Equipment
<br />
<br />The HIPLEX program acquired two 5 cm (C band)
<br />wavelength, 10 beam width radar systems with digital
<br />recording capability, which were located at Miles City,
<br />Mont., and Goodland, Kan. Each is housed in a separate
<br />semitrailer and both are equipped with a digital video
<br />integrator and processor (DVIP) similar in operation
<br />and accuracy to the DVIP designed and described by
<br />the National Severe Storms Laboratory (Sirmans and
<br />Doviak, 1973). The radars are capable of detecting
<br />minimum equivalent reflectivities (Ze) of -10 dBZ
<br />at 2S km and + 5 dBZ at 150 km. Table 1 summarizes
<br />the characteristics of the HIPLEX SWR-75 radars.
<br />Digital recording capabilities for each system consist
<br />of two 9-track, 800 cpi, odd parity, computer com-
<br />patible magnetic tape recorders with read-after-write
<br />recording. Two recorders per system permit tape
<br />changes to take place without loss of data. Each digital
<br />system has read capabilities which permit a field check
<br />of tapes before they are sent to the computer center for
<br />processing. This can give an early indication of some
<br />radar system problems which may occur. In addition,
<br />the HIPLEX radar system is designed so that aircraft
<br />positions are monitored on a remote PPI scope, which
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