field observing facility national center for atmospheric

John McCarthy and James W. Wilson Field Observing Facility

National Center for Atmospheric Research2

Boulder, Colo. 80307

The Joint Airport Weather Studies t . t ^ f X " Department of Geophysical Sciences

University of Chicago Chicago, 111. 60637

Project

Abstract

The Joint Airport Weather Studies (JAWS) Project will investigate the microburst event, having 2-10 km spatial and 2-10 min tempo-ral scales, at Denver's Stapleton International Airport during the summer of 1982. JAWS applications and technology transfer objec-tives include: broadening the data base; providing data for real-time detection of thunderstorm hazards for dissemination to the public and avaiation communities; examining aircraft performance in wind shear; providing a real-time test for display software; identifying which scales of atmospheric motion are pertinent to applied objec-tives; providing a test of optimal Doppler radar placement suitable for metropolitan and airport terminal coverage; and describing in more detail the microburst hazard.

1. Introduction

The Joint Airport Weather Studies (JAWS) Project is a joint research and technology transfer effort of the National Center for Atmospheric Research (NCAR) and the Univer-sity of Chicago. The project began on 1 October 1981 and will continue for three years. The principal focus of JAWS will be on the convective microburst event, a small region of intense downflow and associated outflow that occurs in the convective boundry layer, usually, but not always, associated with thunderstorms. The microburst has a spatial and temporal scale of 1 to 4 km and 2 to 20 min, respectively, and has proved to be a major factor in a number of aircraft accidents, as reported in Fujita and Caracena (1977), McCarthy et al. (1979, 1980), and Fujita (1980).

JAWS will conduct research on the fine-scale structure of thunderstorm kinematics in the vicinity of Denver's Staple-ton International Airport during the summer of 1982. The effect of thunderstorm-produced, low-level wind shear on

"A version of this paper appears in the Preprints of the Confer-ence on Radar Meterology, American Meterological Society, 30 November-3 December 1981, Boston, Mass. Information concern-ing the Joint Airport Weather Studies Project (JAWS) can be obtained from one of the following: Dr. John McCarthy, JAWS Project Office, National Center for Atmospheric Research, P.O. Box 3000, Boulder, Colo. 80307 (Phone: (303) 497-0651 or FTS 322-7651); Dr. T. Theodore Fujita, JAWS Project Office, Dept. of Geophysical Sciences, University of Chicago, 5734 S. Ellis Ave., Chicago, 111. 60637 (Phone: (312) 753-8639).

2NCAR is sponsored by the National Science Foundation. 0003-0007/82/010015-08$06.00 © 1982 American Meterological Society

aircraft performance will be studied, and a number of detection and warning systems will be tested in an active thunderstorm wind shear environment. JAWS facilities will include three NCAR Doppler radars (two 5 cm and one 10 cm), the Portable Automated Mesonet (PAM), two research aircraft, three rawinsonde units, and a lightning detection system.

JAWS has many applications and technology transfer objectives that are related to NOAA's Prototype Regional Observing and Forecasting Service (PROFS); to the NOAA, Federal Aviation Administration (FAA), Depart-ment of Defense (DOD) Next Generation Doppler Radar Program (NEXRAD); and NASA's Office of Aviation Safety Technology (OAST) Program. Consequently, a close working relationship will exist among JAWS, PROFS, NEXRAD, and OAST. These applied programs will benefit by: Broadening the general weather hazard data base; providing data appropriate for real-time detection and warn-ing of thunderstorm hazards for dissemination to the public and the aviation community; examining aircraft perfor-mance characteristics in wind shear conditions; providing a suitable real-time test bed for display software development; providing additional means to identify which scales of atmo-spheric motion are pertinent to applied objectives; providing an excellent test of optimal Doppler radar placement suit-able for metropolitan and airport terminal coverage; and giving a more detailed perspective on the microburst hazard.

In the sections to follow, a scientific background to the microburst will be presented, followed by a more detailed description of the objectives of JAWS.

2. The microburst

All convective clouds contain updrafts and downdrafts. In cumulus congestus clouds, sailplane (Paluch, 1979) observa-tions indicate that small, strong downdrafts are common. It is likely that these downdrafts are caused by the penetrative mixing mechanism proposed by Squires (1958). This mecha-nism assumes dry environmental air is entrained near cloud tops and mixed with the cloud air, producing sufficient evaporative cooling to generate downdrafts that penetrate several kilometers into the cloud. Downdrafts also are initiated and existing ones enhanced by precipitation drag (Clark and List, 1971), and evaporative cooling from rain falling in dry air (Kamburova and Ludlam, 1966).

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16 Volume 63, Number 1, January 1982

Observations of high plains or desert convective storms suggest that dry sub-cloud air is particularly important in generating and maintaining strong downdrafts through the evaporative cooling process. Although extensive evidence is lacking, even rather benign-appearing clouds in these regions may produce intense, small scale downdrafts and corresponding outflow. Lemon and Doswell (1979) have proposed that downdrafts on the rear flank of severe thun-derstorms originate at a height of 7 to 10 km. They further propose that downdrafts are dynamically forced by the nonhydrostatic component of the vertical pressure gradient like those formed on the upwind side of tall buildings in strong winds. Klemp and Wilhelmson (1978) have simulated this process in their three-dimensional numerical model.

Most downdrafts do not reach the ground, since just the right balance of entrainment and evaporation of liquid water must take place to keep pace with adiabatic warming. However, when they do reach ground, they spread horizon-tally. The stronger the downdraft penetrating the boundary layer, the stronger the resulting outward burst of horizontal winds. Fujita (1978) has defined those downdrafts that induce near-surface horizontal maximum winds exceeding 18 m/s (40 m/h) as "downbursts." He further defines a downburst having a damage path less than 5 km as a "microburst." When a downdraft reaching the ground continues as an expanding outflow, extending over more than a few kilometers, a gust front is formed. Thus, a microburst can evolve into a gust front. Gust fronts can originate from either one or numerous cloud-scale or meso-scale downdrafts that Zipser (1977) has shown to be present with some squall lines.

Multiple Doppler radar analysis of the JAWS data will provide, for the first time, high-resolution data on downdraft profiles from cloud top to ground, and on the lifetime and scale of wind shear events given in Table 1.

It is unknown what special physical mechanisms cause downdrafts to reach downburst intensity; it also is unknown if these stronger downdrafts have a different origin. Basing his considerations on scale, Emanuel (1981) proposes that downbursts are caused by penetrative downdraft mecha-nisms (Squires, 1958). He also states that because of the small scale of the downburst, current numerical thunder-storm models are incapable (e.g., Schlesinger, 1978; Klemp and Wilhelmson, 1978; Clark, 1979) of simulating the downbursts. However, he believes that these models should be capable of explicitly resolving penetrative downdrafts if the model spatial resolution were greatly increased. A goal of JAWS will be to provide modelers with sufficient four-dimensional detail and insight into dynamical forcing

mechanisms of microbursts to encourage model modifica-tions, so that downbursts might be simulated.

The best documented microburst cases to date occurred during the Northern Illinois Meteorlogical Research On Downbursts (NIMROD), which took place near Chicago for 45 days in the spring of 1978. In NIMROD, an accurate a priori estimate of the number of microbursts in and around the network was impossible for lack of data; consequently, Doppler radar baselines of 60 km were chosen in order to increase the probability of an observable event. At the conclusion of the operations, as many as 10 microbursts, five gust fronts, and two supercells were documented. The basic difficulty encountered was attributable to the ground clutter and the curvature of the earth, which obstructed the detec-tion of the low-level winds at distances in excess of 30 km. Thus, near-ground velocities could only be detected by one radar. No dual or triple Doppler measurements of micro-bursts at low levels were obtained. Nonetheless, some micro-bursts were depicted by single Doppler radar, permitting estimations of important characteristics of the low-level wind shear.

The best microburst case, which passed by the Yorkville, 111. (YKV) NCAR 5 cm Doppler radar on 29 May 1978, allowed a continuous data acquisition from 15 to 3 km distance. The leading edge of the microburst, after passing near the Doppler radar, turned gradually into a weak gust front, which reached O'Hare International Airport one hour later. The peak-gust speed, 31 m/s at YKV, decreased to 20 m/s after travelling 20 km, and to 10 m/s near O'Hare. The estimated lifetime of the microburst with its peak-gust speed in excess of 30 m/s was 10 min. The rainfall rate during the peak-gust time at YKV was 30 mm/h (0.02 in/min). Since no multiple Doppler radar observation of low-level outflow was possible because of the obstruction and earth curvature problems discussed earlier, divergence and vertical motion estimates were obtained as follows:

It was assumed that the horizontal airflow of a microburst is a cylindrically symmetric radial outflow phenomenon superimposed upon the translational velocity. Figure 1 pre-sents the geometry of measuring the Doppler velocity Kof a microburst characterized by the translational velocity C0

and the radial velocity u. By using angles 6, 0O, and 0, and .ranges r and R in the figure, we express Doppler velocity by

V= u cos(6 + 0) + C0 cos(0O + 0). (1)

Selection of the cases with small 6 and 60 along with r < R0

permits reduction of this equation to

V = u cos 6 + C0 (2)

T A B L E 1. Horizontal scale, lifetime, and maximum wind speed of wind-shear disturbances associated with convective storms. Average dimension of the mesoscale is 10 to 100 km, and that of the misoscale (my-so), 0.1 to 1 km, according to Fujita (1979).

Artificially dividing the dimension between the meso- and misoscales is 4 km.

Horizontal dimensions Wind-shear Maximum disturbances (in km) (scale) Lifetime wind speed

Gust front 10-100 Mesoscale 1-10 h 40 m/s Downburst 4-10 Mesoscale 10-60 min 50 m/s Microburst 1-4 Misoscale 2-20 min 60 m/s


Bulletin American Meteorological Society 17

FIG. 1. Divergence computation based on single-Doppler veloci-ties of a microburst which is approaching a Doppler radar, where V is Doppler-measured velocity, u is radial outflow velocity, and C0 is translational velocity of approaching microburst.

resulting in the solution of

u = (V - C0)/cos 0. (3)

Divergence inside the microburst is computed as

u du Div u = — + — (4)

r dr

Two terms on the right side of this equation obtained from Eq. (3) are

u_ V - C0 _ V - Cp r r cos 0 r0

du 1 dV dV dr cos 0 dr dr0

(5)

(6)

where r0 = r cos 0 is the distance from the microburst center to the velocity element projected onto the Doppler radar-microburst center line. By estimating C0, the translational velocity, we compute divergence values from

Div u = -C0 ^ dV r0 dr0'

(7)

Using divergence values derived in the above manner and the mass continuity equation, we then obtained vertical velocities. Figure 2 presents isotachs of horizontal wind speeds and vertical velocities for the NIMROD microburst case, computed from Eq. (7) as it is applicable to the travelling radial outflow of the microburst, which is not necessarily axi-symmetric in the earth fixed frame of refer-ence.3

While these analyses closely resemble the actual flow, these results should be considered as conceptual findings. JAWS should provide high-resolution horizontal wind fields that will allow for the removal of these assumptions, and greatly improve the validity of microburst analyses.

The maximum horizontal wind speed of 31 m/s represents an extreme wind shear situation for an aircraft on immediate approach to, or departure from, an airport. Figure 3 graphi-

FIG. 2. A vertical cross section through the 29 May 1978 microburst, showing isotachs of horizontal wind-speeds. The height of the maximum wind is estimated to be 50 m or lower. Arrows are ground-relative velocities in the plane, which is stretched vertically (from Fujita (1980)).

cally illustrates the critical nature of such a microburst on aircraft operations. Such phenomena are addressed from a critical aircraft performance perspective in McCarthy et al. (1979, 1980) and by Turkel and Frost (1980).

In response to these preliminary findings regarding micro-bursts, and in an effort to address a number of problems related to effects of microbursts, as well as to a host of ancillary problems, the JAWS Project has emerged.

3. The J A W S Project

We have established a major project dedicated to a thorough

3Single Doppler computations for Fig. 2 were made with 0O = 2°, 0 - 3°, and 0 = 1°.

FIG. 3. A vertical-time cross section showing isotachs of horizontal wind speed through a downburst observed by an NCAR Doppler radar near O'Hare airport on 7 June 1978. Included is a hypothetical penetration through the maximum-wind core along 3° glide slopes. The headwind shear (headwind increase with time) is experienced during the approach to the core, while the tailwind shear (headwind decrease or tailwind increase with time) is encoun-tered while flying away from the core. A strong tailwind shear results in a loss of airspeed, which endangers both landing and takeoff operations. It should be noted that a surface wind station (PAM 7) failed to measure high winds until three minutes after the passage of the maximum wind, less than 300 m above the station. From Fujita (1980).


Volume 63, Number 1, January 1982

Block diagram of JAWS Project objectives and observing facilities.



FIG. 5. Map illustrating JAWS Project facilities situated in the vicinity of Denver's Stapleton International Airport.

examination of fine-scale, low-level kinematics and dynamics associated with convective storms. JAWS is a collaborative effort between the University of Chicago and NCAR. A block diagram of the JAWS Project is presented as Fig. 4. A brief inspection of the project structure indicates a division of the effort into three areas: basic studies of low-level convective storm winds, aircraft performance in wind shear conditions, and wind shear detection and warning techniques. Note that many of the detection and warning systems will be part of the overalj observation system. A secondary but important part of the JAWS project is labelled as ancillary studies, which represents the involve-ment of several other groups with JAWS-related objectives.

A list of the observing facilities to be used also is shown. Figure 5 is an illustration of the JAWS observing facilities distributed around Stapleton International Airport.

The program is managed jointly by Theodore Fujita of the Satellite and Mesometeorology Research Project of the University of Chicago, and John McCarthy and James Wilson of the Field Observing Facility of NCAR; each institution has established and staffed a JAWS office. The JAWS Project will cover a three-year-period, with the field phase being conducted between 15 May and 15 August 1982. We shall operate the experiment in the vicinity of Stapleton International Airport at Denver, Colo. There are several reasons for choosing Denver; most importantly,



T A B L E 2. Number of thunderstorm days per month for several selected stations in the United States, based on National Weather Service data for the period 1960-69.

Month Denver Colorado Springs Miami

Oklahoma City Chicago Wash., D.C. Tucson

April 2 3 5 6 3 3 1 May 6 10 8 10 6 5 1 June 9 12 12 11 8 6 1 July 12 18 14 7 6 8 15 Aug. 10 15 17 7 7 6 15 Sept. 4 7 9 5 4 3 7 TOTAL 43 65 65 46 34 31 40

Denver has a high frequency of thunderstorms and, we believe, a high frequency of microburst-producing storms. This is likely the result of the dry environment, and thus high potential for evaporational cooling to enhance downdrafts. Table 2 shows that Denver has a frequency of thunderstorms equivalent to Oklahoma City, and that Colorado Springs, Colo. (110 km south of Denver), has a frequency equal to that of Miami. In fact, the Palmer Divide area between Denver and Colorado Springs may have one of the highest frequencies of thunderstorms in the country. From over 100 h of Doppler radar observations during the summer of 1980, we have observed that these storms frequently produce gust fronts and microbursts.

The Denver location also is attractive because of the installation of the Low-Level Wind Shear Alert System (LLWSAS) at Stapleton, and the presence of NOAA Wave Propagation Laboratory's vertically pointing 1 GHz Doppler wind profiler expected to be in operation in FY 1981. In addition, the Boulder Atmospheric Observatory's (BAO) instrumented tall tower east of Boulder is well within the multiple Doppler radar array, and will be available for use in JAWS. NOAA's PROFS program located in the Denver vicinity will provide JAWS with substantial data on the mesoscale, and, in turn, PROFS will benefit from availabil-ity of the JAWS data sets for use in evaluating its forecast-ing techniques. Finally, costs will be minimized in Denver by virtue of the proximity of the observing facilities.

a. Basic scientific objectives

The core of the JAWS Project emphasizes fundamental scientific studies of the thunderstorm, with particular atten-tion to the surface and planetary boundary layer. A major objective is to explore quantitatively the nature of the microburst. It is hard to believe, however, that the compli-cated mechanism that initiates microbursts can be under-stood without knowing the mesoscale environment in which they form, develop, and die. The basic questions related to such scale interactions are:

1) Since most thunderstorms are associated with moder-ate to strong downdrafts during their mature to dissi-pating stages, why do only a fraction of them induce downbursts or microbursts?

2) Is there a typical source region for the downburst? Do downbursts, which are larger than microbursts,

descend from higher levels? Some meteorologists believe that the source height of the descending air must be middle to low levels, while others propose a long-distance descent from near the cloud top to the ground.

3) What physical mechanisms are responsible for gener-ating microbursts? What is the relative importance of the following: Penetrative downdraft, precipitation drag, below-cloud evaporative cooling, dimension of the precipitation region, obstacle flow, pressure forces, and environmental stability?

4) Is there a relationship between overshooting tops, subsequent downdrafts, sinking tops, and microbursts? If so, what are the relationships among these phenom-ena?

5) Can we distinguish downburst-inducing thunder-storms from other types, based on radar and/or satel-lite measurements?

b. Applications

A broad complement of applied problems are being addressed in JAWS. We are interested not only in basic definition of microburst phenomena, but also in their specific effects on aircraft performance, and how they can adequately be detected. The following are a few of the applications-oriented questions:

1) Can we numerically model aircraft performance in such a way as to consider accurately the time-dependent, often periodic nature (see Fig. 3) of the microburst? Aeronautical engineering models have long been used in addressing step function gust inputs, but they do not take into account the small scale fluctuations of longitudinal, latitudinal, and vertical gusts occurring in the microbursts. Such performance characterizations will be addressed using numerical models; manned flight simulators; and instrumented meteorological research aircraft operating in the JAWS Project, as well as the performance of civil airliners within the data collection volume of JAWS.

2) How do existing and planned low-level wind shear detection and warning systems fare in a uniform thunderstorm wind shear environment? The six systems listed in Fig. 4 will be tested in JAWS, resulting in an objective evaluation of their capability.



In this regard, several new technologies associated with pulsed microwave. Doppler weather radar will be further developed and evaluated.

Several applications of the JAWS Project are somewhat indirectly associated with JAWS. In Fig. 4, we have identi-fied these as ancillary studies. A close association with NOAA's PROFS Program Office constitutes a serendipi-tous relationship. PROFS will be using the NCAR CP-2 10 cm Doppler radar for a full year in Denver, to demonstrate the detection, assimilation, and warning of weather hazards in a test-of-concept of mesoscale technology as applied to the short-range forecast or "nowcast." JAWS will jointly use CP-2 during the summer of 1982 and will profit from the mesoscale descriptive context provided by PROFS, while PROFS will gain from JAWS radar technique development and detailed specific hazard definition.

The NOAA/FAA/Air Force NEXRAD Program will gain from JAWS in two significant areas. By examining the placement of three Doppler radars at three different ranges from an airport terminal/urban area setting, the appropriate trade-offs for NEXRAD radar placement will be examined. For example, will national radar network placement be sufficient, or will additional airport/urban Doppler radars be required? Secondly, quantitative techniques for weather hazard definitions will be developed further in the JAWS Project, after Wilson et al. (1980) and Wilson and Wilk (1981), thus aiding the software development objectives of NEXRAD.

While we cite only a few of the applications and technol-ogy transfer objectives of JAWS, we see the project as being a complete basic and applied attack on a fundamental meteorological problem, most worthy of pure science and mission agency support.

all combine to miss the smaller and short-lived microburst and to accentuate large scale features such as gust fronts, major updraft-downdraft couplets, and mesocyclones.

Mesoscale thunderstorm research has been left with a scientific void that the JAWS Project will attempt to fill. There must be a thorough investigation of small scale thunderstorm events that, as it turns out, constitute a serious threat to aircraft in the terminal environment. The JAWS Project has designed an observation network that is suffi-ciently dense to define the x, y, z, and t scales of the microburst-type events, to understand their life cycles, and to identify the physical bases of the origin and evolution of downdrafts, and how they relate to the development of microbursts and gust fronts. Additionally, we shall examine the relationship of microburst and other boundary-layer wind shear events to the larger thunderstorm scale studied in previous experiments.

Acknowledgments. Many persons have been vital to the success-ful development of the JAWS Project. Much of the groundwork was laid at a series of workshops entitled Workshop on Meteorological and Environmental Inputs to Aviation Systems, sponsored by NASA, FAA, and NOAA, held annually at the University of Tennessee Space Institute, Tullahoma, Tenn. Walter Frost of UTSI and Dennis Camp of NASA Marshall Space Flight Center, Hunts-ville, have led these discussions, and were instrumental to the development of the JAWS Project. Dr. Ron Taylor of NSF, Robert Roche and Frank Coons of FAA, Dick Tobiason of NASA, and Ron Alberty and Jack Hinkelman of NOAA are acknowledged for support. Ms. Phyllis O'Rourke is acknowledged for editing the manuscript. Ms. Billie Wheat and Ms. Maggie Miller are acknowl-edged for typing.

4. Conclusions

This study will concentrate on scales of motion that have received little attention in previous experiments. The micro-burst-type wind shear event occurs on space and time scales ranging from 1 to 3 km and 2 to 20 min, respectively. Essentially, all thunderstorm-oriented mesoscale experi-ments have deployed their multiple Doppler radar arrays with spacings too large to observe adequately these impor-tant scales. The SESAME 1979 experiment concentrated on storm-scale and large scale processes ranging in excess of 5 km. The Convective Storms Division of NCAR (and its predecessor—the National Hail Research Experiment) occasionally looked at smaller scales than SESAME 1979, but concentrated on prethunderstorm precipitation develop-ment. This continued to be the case in the 1981 Cooperative Convective Precipitation Experiment (CCOPE) at Miles City, Mont. The NIMROD experiment in 1978, planned at the onset to concentrate on smaller scales, used Doppler radar spacing suitable for storm scale studies, and thus could not provide multiple Doppler analyses that addressed the microburst. Large separations between radars, slow scan-ning procedures, and failure to observe close to the ground,

References

Clark, T. L., 1979: Numerical simulations with a three-dimensional cloud model: Lateral boundary condition experiments and multi-cellular severe storm simulations. J. Atmos. Sci., 36, 2191-2215.

, and R. List, 1971: Dynamics of a falling particle zone. J. Atmos. Sci., 28, 718-727.

Emanuel, K. A., 1981: A similarity theory for unsaturated down-draft within clouds. J. Atmos. Sci., 38, 1541-1557.

Fujita, T. T., 1978: Manual of downburst identification for project NIMROD, SMRP Res. Pap. 156, University of Chicago, 111., 104 pp.

, 1979: Objectives, operation, and results of Project NIMROD. Preprints, 11th Conference on Severe Local Storms (Kansas City), AMS, Boston, pp. 259-266.

, 1980: Downbursts and microbursts—an aviation hazard. Preprints, 19th Conference on Radar Meteorology (Miami Beach) AMS, Boston, 637-644.

, and F. Caracena, 1977: An analysis of three weather-related aircraft accidents. Bull. Am. Meteorol. Soc., 58, 1164-1181.

Kamburova, P. L., and F. H. Ludlam, 1966: Rainfall evaporation in thunderstorm downdrafts. Quart. J. Roy. Meteorol. Soc., 92, 510-518.

Klemp, J. B., and R. B. Wilhelmson, 1978: Simulations of right and left moving storms through storm splitting. J. Atmos. Sci., 35, 1097-1110.



Lemon, L. R., and C. A. Doswell III, 1979: Severe thunderstorm evolution and mesocyclone structure as related to tornado genesis. Mon. Wea. Rev., 107, 1184-1197.

McCarthy, J., E. F. Blick, and R. R. Bensch, 1979: Jet transport performance in thunderstorm wind shear conditions. NASA CR-3207, NASA, Washington, D.C.

, W. Frost, B. Turkel, R. J. Doviak, D. W. Camp, E. F. Blick, and K. L. Elmore, 1980: An airport wind shear detection arid warning system using Doppler radar. Preprints, 19th Conference on Radar Meteorology, (Miami Beach) AMS, Boston, pp. 135— 142.

Paluch, I. R., 1979: The entrainment in Colorado cumuli. J. Atmos. Sci., 36, 2462-2478.

Schlesinger, R. E., 1978: A three-dimensional numerical model of an isolated thunderstorm: Part I. Comparative experiments for variable ambient wind shear. J. Atmos. Sci., 35, 690-713.

Squires, P., 1958: Penetrative downdraughts in cumuli. Tellus X, 3, 381-389.

Turkel, B. S., and W. Frost, 1980: Pilot-aircraft system response to wind shear. N A S A Contractor Report CR-3342, NASA, Wash-ington, D.C.

Wilson, J., R. Carbone, H. Baynton, and R. Serafin, 1980: Opera-tional application of meteorological Doppler radar. Bull. Am. Meteorol. Soc., ttl, 1154-1168.

Wilson, J. W., and Kenneth E. Wilk, 1981: Nowcasting applications of Doppler radar. Proceedings of the International Commission of Cloud Physics Symposium entitled "NOWCASTING: Meso-scale Observations and Short Range Prediction," Hamburg, Germany, 25-28 August 1981, pp. 123-134.

Zipser, E. J., 1977: Mesoscale and convective-scale downdrafts as distinct components of squall-line structure. Mon. Wea. Rev., 105, 1568-1587.

announcements ( c o n t i n u e d from page 14)

Science and Technology Political Action Committee

A former Congressman and scientist recently wrote that: "There is no major group in the U.S. so ignored, ridiculed, misunderstood or underestimated in our legislative bodies as the scientists of our country."

A group of scientists and engineers, who previously served as Science Fellows in the Congress or in the State Department, is trying to change this image. They have formed the Science and Technology Political Action Committee (SCITEC-PAC). The Chairman of the founding group, Donald Stein of Clark University, stated, "It is critical that the community of scientists and engineers, regardless of their specific disciplines, develop the political strength to influence public policy. If we don't , we will have to stand by and watch the funds for education, training, and research decline to dangerously low levels."

SCITEC-PAC is a non-partisan organization concerned with the support of science in its broadest sense, from the role of the Federal Government in funding science and engineering research and teach-ing to the development of tax laws for encouraging business invest-ment in education and research.

Stein explained, "Our group decided to organize as a PAC rather than as a lobby because of the differences in goals. Lobbyists try to influence officials on specific issues by presenting information to them, while PACs hiake campaign contributions of money, time, and effort to candidates that share similar goals and aspiratioris. An extra advantage of having a PAC for all sciences is the added clout it provides the many scholarly and professional societies. Because of their tax-exempt status, organizations such as the A A AS, American Chemical Society, and National Academy of Sciences cannot sup-port political candidates."

The response during the initial stages of S C l T E C - P A C s organiz-ing activities has been very encouraging. Stein commented, "There are some scientists and engineers who feel political action by our community is somehow inappropriate or undignified. At some point, the scientific community will have to accept what other inter-est groups have learned long ago — that our system of government assumes that different groups will organize to make their interests known to Congress and the President. Given the current economic situation, the question is not IF the scientific and engineering com-munity will organize but whether it will organize NOW or wait until it has lost even more battles to the budget ax. Politicians must be reminded that support of American science and technology on a

broad scale is in the national interest. If we do not speak out, who will? If not now, when?"

The Advisory Board of SCITEC-PAC includes distinguished individuals from governments, teaching, and research: Robert C. Anderson, Vice-President for Research, University of Georgia; David H. Cohen, President, Society for Neurosciences; Hugh Fudenberg, Chairman, Dept. of Basic and Clinical Immunology, Medical University of South Carolina; George Gamota, Director, Institute of Science and Technology Policy, University of Michigan (formerly the Director of Research for the Dept. of Defense); Nor-man Geshwirid, Putnam Professor of Neurology, Harvard Univer-sity; Donald McCurdy, President, National Science Teachers Association; Gilbert Omenn, University of Washington, Seattle (formerly the Associate Director of the Office of Science and Tech-nology Policy); and Adlai Stevenson III, former Senator from Illi-nois and Chairman of the Senate Subcommittee on Science Research and Technology.

For further information, contact SCITEC-PAC, Rockvilie Court House Station, P.O. Box 351, Rockvilie, Md. 20850 (tel: 301-424-0002).

New booklet on career workshops for women in science

A 53-page booklet, Ideas for Developing and Conducting a Women in Science Career Workshop, has been published to assist those wishing to provide career advice to prospective women scientists and engineers. Topics covered include managing and financing the work-shop, recruiting presenters and participants, generating publicity, collecting resource materials, holding the workshop, conducting the evaluation, and developing on-going and new activities. This book-let also includes samples of brochures and evaluation forms, a list of resource materials, a list of directors of NSF-supported workshops, and lists of committees concerned with women and minority scientists.

The booklet is available without charge from the Women in Science Program, Directorate for Science and Engineering Educa-tion, National Science Foundation, Washington, D.C., 20550. Each request should be accompanied by a mailing label.

(icontinued on page 28)


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