|
<br />._'T ---
<br />
<br />..
<br />
<br />..,
<br />
<br />.(
<br />
<br />Table 2. Su~nary of Results
<br />10 ern 5-1 Lift
<br />
<br />20 em s-lLift
<br />
<br />It
<br />
<br />No Lifting
<br />
<br />Date
<br />
<br />July 2,
<br />1977
<br />
<br />Base
<br />Height
<br />(km)
<br />
<br />o
<br />
<br />Cloud Top Total Number Base I Cloud Top I Total- Number Base
<br />min. max. Depth of Height - min. max.! Depth of Height
<br />(km) Il<m\ Clouds Ikm\ ~ II,~\ Clouds Il<m\
<br />
<br />Cloud Top
<br />min. max.
<br />
<br />{..~\
<br />
<br />'rotal Number
<br />Depth of
<br />n. Clouds
<br />
<br />o
<br />
<br />o
<br />
<br />o
<br />
<br />o
<br />
<br />4.3
<br />
<br />Aug. 24.
<br />1977
<br />
<br />May 24,
<br />1978
<br />
<br />o
<br />
<br />o
<br />
<br />o
<br />
<br />o
<br />
<br />1.3
<br />
<br />o
<br />
<br />3.715 4,0 11. 6
<br />
<br />14.4
<br />
<br />3
<br />
<br />4.0
<br />
<br />e.
<br />
<br />Table 2 provides a summary of model
<br />diagnosed ddVelopment using the Goodland rawin-
<br />sOl1c3e at 1800 GMT: The most intense cases of
<br />August 24, 1977 and May 24, 1978, agreed well
<br />with observed cloud development which was largely
<br />confined to mesoscale lines of thunderstorms
<br />probably associated with organized lifting. The
<br />location of preferred development diagnosed in
<br />the isentropic analysis on these days was also
<br />in good agreement with the observed cloud devel-
<br />_.____opment shown in Table 1. The differences between
<br />cases in the number of clouds predicted, total
<br />cloud depth supported by convection, and the
<br />cloud top heights diagnosed by the model for the
<br />three cases also tended to agree with those
<br />observed, That is, the observed cloud-top
<br />heights in the deepest convection on August 24,
<br />1977 agreed with radar observations of a squall
<br />line that developed in eastern Colorado and
<br />moved through Kansas. In the weakest case on July
<br />2, 1977, fewer clouds and a lower cloud depth
<br />were also diagnosed by the model. We must note
<br />Fhat~a larger sample of cases is required to
<br />properly evaluate model diagnoses of convect~n
<br />potential under the influence of mesoscale isen-
<br />tropic vertical motion; however, these prelimin-
<br />ary analyses are encouraging.
<br />
<br />6.
<br />
<br />CONCLUSIONS
<br />
<br />
<br />~. a, Lifting is a key factor in the
<br />release of available potential instability (API)
<br />on the High Plains, Nearly all days appear to
<br />have.suffi:ie~~~o pro~uce deep.con~ection.
<br />prov~ded l~ft~ng or~echan~cal forCIng IS applIed.
<br />
<br />~ b. Cross-isentropic vertical velo-
<br />cities provide a major input to the release o~
<br />
<br />The MESOCU model seems to be a
<br />assessing the effects of lifting
<br />~
<br />
<br />d. This technique of combining isen-
<br />tropic vertical motion with model deagnosed~~
<br />appears to be useful not only for forecasting the
<br />development of convective activity but also may be
<br />used to produce covariates in the evaluation of
<br />weather modification in the High Plains.
<br />
<br />c.
<br />useful tool in
<br />on the release
<br />
<br />-
<br />
<br />7.
<br />
<br />ACKNOWLEDGEMENTS
<br />
<br />Many thanks go to Drs, Carl Kreitzberg
<br />andOon Perkey, who developed the original MESOCU
<br />model. Dr. C.A. Grainger, site director of the
<br />HIPLEX-Goodland program for his thoughtful
<br />
<br />12. 1 12, ~ 24. 1
<br />
<br />:::: i :
<br />,~
<br />
<br />3
<br />
<br />3.96
<br />
<br />o 13.
<br />
<br />13.11 14.1 35.0
<br />
<br />5
<br />
<br />2.21
<br />
<br />13.8 15.
<br />
<br />4. 1 11.1 29. 1
<br />
<br />4.0
<br />
<br />4.1 12.
<br />
<br />5
<br />
<br />con~ents throughout the development of this paper.
<br />!IIIessrs. Fran Politte and Douglas HalLe who devel-
<br />oped the Environmental Data Network software
<br />which made all HIPLEX and NWS data readily avail-
<br />able for analysis. Our add~U'~ s is given to
<br />Mr. Richard Eddy for his heJ,pf r view and
<br />suggestions, .
<br />
<br />This research was sponsorE!d by the
<br />U,S. Bureau of Reclamation's Office of Atmospheric
<br />Resources Management under contract 14-06-0-7673,
<br />
<br />8.
<br />
<br />REFERENCES
<br />
<br />Carlson, T,N. and F,H, Ludlum, 1968:: "Conditions
<br />for the Occurrence of Severe Local Storms",
<br />Tellus, vol. 22, no. 2, pp 203--226
<br />
<br />COl'bell, P., and C.J. Callahan and W.J. Kotsch,
<br />1976: The GOES/SMS Users Guide, NOAA, NESS,
<br />World Weather Building, Camp Spring, Md.
<br />
<br />-r-
<br />~ Krei tzberg, C" and 0, Perkey, 1976" "Release of
<br />Potential Instability: Part lA Sequential
<br />Plane Model Within a Hydrostatic Primitive
<br />Equation Model," J, Atm. Sci., vo1.33, no. 3,
<br />pp 456-475
<br />
<br />Matthews, D. and L. Koshio, 1977: "Analysis of
<br />Mesoscale Triggering Mechanism from SynChro-
<br />nous MeteorOlogical Satellite Imagery," AMS
<br />Preprint, 6th Conference on Pl.lIlned and
<br />Inadvertent Weather Modification
<br />
<br />Modahl, A.C., 1974: A Description of In-The-Field
<br />Synoptic Analysis Activities In Support of
<br />the National Hail Research Experiment, Preprint
<br />Volume 4th Conference on WeathE!r Modification,
<br />AMS, November 18-21, 1974
<br />
<br />Politte, F., D. Hale, and D. Matthe~ls, 1977: The
<br />Bureau of Reclamation's Environmental Data
<br />Network, AMS Preprint, 6th Conference on
<br />Planned and Inadvertent Weather Modification
<br />
<br />Stommel, H., 1951: Entraimrent of Jdr Into a
<br />Cumulus Cloud. J, Appl, Meteor. 8, pp 127-129
<br />
<br />185
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