It is believed that Doppler radar would aid in by tgv36994

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									JANUARY
      1961                                         MONTHLY W E A T H E R REVIEW                                                                      7
   There are some major changes in the present equipment           cloud in sufficient’ time to warn those in threatened areas.
that shouldbe madeinordertohavewhat,                   wouldbe     It is believed that Doppler radar would aid in easing this
considered an optimum Doppler radar for meteorological             problem so that we cangreatlyimproveourabilityto
purposes. Theseare:        (1) 5.4-crn. wavelengt,h, ( 2 ) pulse prevent’ loss of life due to those stornls.
inst>ead of cw techniques, and (3) provision of “sense”
to det)ermine directions of motions.                                                        ACKNOWLEDGMENTS
   The use of 5.4-cm. wavelength would reduce attenua-
                                                    the
tion problem considcrablS. Since there is      :t clear channel,      5Ir. V:Luglln D. Rocknev, C’hief, Observations Section,
5600-5650 mc.,assigned tometeorology,itsusewould                   U.S. Weat~her Bureau, Washington, D.C. assisted in this
reduce the chances of interference with other             r‘ d ars project. It TVM mostly through his efforts and enthusiasm
                                                           <L
operating in the C-band.                                           that this project was made possible. 51r. Stuart G. Bigler,
   The use of pulsed instead of cur techniques would d 1 ow Chief, Radar Unit, U.S. WeatherBureau,Washington,
                                                              1    6



for a tremendousincreaseinpoweroutput’and                 energy D.C. is t’obc thanked forhis valuable assistance and                            many
penetration into storms. In addition, it would be possible suggestions in the preparation of t’his paper. In addition,
to provide for range gating which     cannot, be done by using the assistance of A h . Shreves C . Goodwin, Radar Mete-
the cw technique. This is a very important, feature, since orological Technician, U.S. Weather                                 Bureau,  Wichita
with the reduced at’terluatiorl and increased power output, Falls, Tex.,isgreatlyappreciat’ed.                                 On many occasions
signals would often be received from two or more storms Mr. Goodwin spent very long continuous periods on the
at the same azimuth from the radar site. For example, project                  in    order to    gather                as man?- d a t a as possible.
if the bean1 wereintersecting a nearby storm at, about Without his assist’ilrlcc perhaps ~ n a n y the dntti on hand           of
5,000 feet above the ground and a distant storm a t about today would not have been obtained.
40,000 feet above the ground, the signal return might he
                        of
similar to a composite figures 6B and 8B. This combina-                                                  REFERENCES
tion would appear very much like figure 3B. For this type
of situation there are two possible explanations. Either         :
                                                                 L 1. E. J . Barlow, “Doppler Radar,” Proceedings of the I R E , vol. 37,
funnel or tornado exists in t’he nearby storm, or the high            1949, pp. 34cL355.
                                                                   2. R. ,J. Beebe, “The Photographic Record of the Dallas Tornado,”
speeds are from the distant storm at high altit’udes while           papcr prescnted before the161st Annual RIeeting of thc American
the lower speeds are from the nearby storm.           A Doppler       Meteorological    Society, College Station, Tex., 1957. [See also
radar system with range gating facilities would allow the             Weathcr Note by Research Vnit, U.S. Weather Bureau, Kansas
operat,or todeterminewhichcaseexisted.              It is wort~h- City, Mo., “Measurement of Wind                         Speeds     S e a r a Tornado
while to mention, at this point, that at the t’irne of t’he           Funnel,” M o n t h l yW e a t h e rR e v i e w ,       87,
                                                                                                                          vol.     S o . 10, Oct. 1959,
unique signals from the El Dorado st,orrn, there were no 3. p. 382.1   S. G. Bigler, “TheDallasTornado of 2April 1957,” Scientific
other storms at the same azimuth within the rangeof the               R e p o r t No. 2, under 1T.S. Weather Bureau Contract                 Cu-b-9116,
Doppler radar. The same is true for       t’he storm 15 rnilcs        Department of OceanographyandMeteorology,TexasA                              & R/I
from the radar site, t the same azimuth as the dust devil.
                     a                                                College, College Station, ‘I’cx., 1957.
   Providing “sense” to the systemis a feature that would 4. ,J. Q. Brantley, “Some meather Observatjiow with a Continuous-
                                                                      Wave JlopplcrRadar,” Proceedings of t h eS i z t hW e a t h e rR a d a r
show whether the Doppler shift was upward downwlrd or
                                                                      Con,ference, Cambridge, >lass., 1957, pp. 297-306.
in frequency, thus allowing the operator to det’ermirle if a 5. W . H. Hoecker, Jr., “Wind Speed and Air Flow Patterns in the
majority of the particles were approaching or departing               Dallas Tornado o f April 2, 1957,” M o n t h l y Weather R e v i e w , vol.
from the radar site. This would be especia1l.v advwntage-             88, KO. 5, May 1960, pp. 167-180.
ous in overhead turbulence studies in thunderstorms and            6. 1,. N. Ridenour, Radar S y s t e m E n g i n e e r i n g , AI. I. T. Radiation
                                                                      Laboratory Series, vol. 1, RlcGraw-Hill Book Co., Inc.,                   Xew
in clear air.                                                         York, 1947.
   One of the most critical problems that        rneteorologists 7. A. Sadon-ski,“RadarObservations                         of the EX Dorado,   Kans.
have had to face has been to obt’ain reliable information             Tornado, June 10, 1958,” M o n t h l y H’eather R e v i e w , vol. 86, No.
concerning the actuttl exist’ence of a tornado or funnel              10, Oct. 1958, pp. 405-407.

                                  NEW WEATHER BUREAU PUBLICATION
                         Climatology at            Measurernents,
                                            T.T70~P,                     Methods, and llacllirles, edited by Gerald
                         L. Barger assisted by John C. N~-han, Washington, D.C.,
                                                                             October 1960, 109 pp.
                         For sale by Superintendent of Documents, U.S. Government Print,ing Office,
                         Washington,D.C.Price        65 cents.
                              Describes the functions, scope, and capabilities of the centralized climato-
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       5ii469“80”“2

								
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