RADAR IN METEOROLOGY

RADAR IN METEOROLOGY: BATT AN MEMORIAL AND

40TH ANNIVERSARY

RADAR METEOROLOGY CONFERENCE

EDITED BY

DAVID ATLAS

American Meteorological Society Boston

1990

© American Meteorological Society 1990Originally published by American Meteorological Society Boston in 1990Softcover reprint of the hardcover 1st edition 1990Permission to use figures, tables, and brief excerpts from this publication inscientific and educational works is hereby granted, provided the source is acknowledged. All rights reserved. No part of this publicationmay be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying,recording, or otherwise, without the prior written permission of the publisher.

Typeset and printed in the United States of America by Lancaster Press, Lancaster, Pennsylvania.

Section openers designed by Helga Hardy.

Published by the American Meteorological Society, 45 Beacon Street, Boston, MA 02176.Richard E. Hallgren, Executive DirectorKenneth C. Spengler, Executive Director EmeritusEvelyn Mazur, Assistant Executive DirectorArlyn S. Powell, Jr., Publications Manager

Editorial support provided by Laura Westlund, Pamela Jones, Jon Feld, Linda Esche, Brenda Gray, Harold Nagel, and Susan McClung.

ISBN 978-0-933876-86-6 ISBN 978-1-935704-15-7 (eBook)DOI 10.1007/978-1-935704-15-7

Table of Contents

Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1x

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x1

Tribute to Professor Louis J. Battan Xlll

I. HISTORY

1 Early Developments of Weather Radar during World War II . . . . . 3 ].0. Fletcher

2 Weather Radar in the United States Army's Fort Monmouth Laboratories . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Donald M. Swingle 3 Radar Meteorology at Radiation Laboratory, MIT,

1941 to 1947 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Isadore Katz and Patrick f. Harney

4 Weather Radar at MIT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22 Pauline M. Austin and Spiros G. Geotis

5 A History of Weather Radar Research in the U.S. Air Force . . . . . 32 James I. Metcalf and Kenneth M. Glover

6 Radar Meteorology at the National Severe Storms Laboratory, 1964-1986 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

Edwin Kessler

7 A History of Radar Meteorology in the United Kingdom· . . . . . . . 54 J.R. Probert-fones

8 The Stormy Weather Group (Canada) . . . . . . . . . . . . . . . . . . . . . . . 61 R.H. Douglas

9 History of Radar Meteorology in Japan . . . . . . . . . . . . . . . . . . . . . . 69 Nobuhiko Kodaira and ]ira Aoyagi

10 Radar Meteorology in India: A Brief Historical Perspective . . . . . 77 S.M. Kulshrestha

11 Radar Meteorology in The People's Republic of China . . . . . . . . . 80 Yu-Mao Xu

12 Early Foundations of the Measurement of Rainfall by Radar 86 David Atlas and Carlton W. Ulbrich

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13 Advances in Precipitation Physics Following the Advent of 'Weather Radar . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98

A.S. Dennis and W.F. Hitschfeld 14 Polarization Diversity in Radar Meteorology: Early

Developments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109 Thomas A. Seliga, Robert G. Humphries, and fames I. Metcalf

15 Foundations of Severe Storm Detection by Radar . . . . . . . . . . . . 115 Ralph f. Donaldson

16 The Early Years of Doppler Radar in Meteorology . . . . . . . . . . . 122 R.R. Rogers

17 The History of Radar Studies of the Clear Atmosphere . . . . . . . 130 Kenneth R. Hardy and Kenneth S. Gage

18 Lightning Investigation with Radar . . . . . . . . . . . . . . . . . . . . . . . . 143 Earle R. Williams, Vladislav Mazur, and Spiros G. Geotis

II. SCIENCE AND TECHNOLOGY

19a Technology of Polarization Diversity Radars for Meteorology 153 V.N. Bringi and A. Hendry

19b Technology of Polarization Diversity Radars for Meteorology: Panel Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191

fames I. Metcalf 20a Signal Processing for Atmospheric Radars . . . . . . . . . . . . . . . . . . 199

R. Jeffrey Keeler and Richard E. Passarelli 20b Signal Processing: Panel Report . . . . . . . . . . . . . . . . . . . . . . . . . . . 230

· Dusan S. Zrnic 21a UHF JVHF Radar Techniques for Atmospheric Research and

Wind Profiler Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 235 f. Ro"ttger and M.F. Larsen

21b Clear-Air Radar Technology: Panel Report . . . . . . . . . . . . . . . . . . 282 Ben B. Balsley

22a Meteorological Radar Observations from Mobile Platforms . . . . 28 7 Peter H. Hildebrand and Richard K. Moore

22b AirbornejSpaceborne Radar: Panel Report . . . . . . . . . . . . . . . . . . 315 David P. Jorgensen and Robert Meneghini

23a Cloud Microphysics and Radar . . . . . . . . . . . . . . . . . . . . . . . . . . . . 323 A.R. Jameson and D.B. Johnson

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23b Cloud Microphysics and Radar: Panel Report . . . . . . . . . . . . . . . 341 Kenneth V. Beard and Robert M. Rauber

24a Convective Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348 Peter Ray

24b Convective Dynamics: Panel Report . . . . . . . . . . . . . . . . . . . . . . . 391 R. Carbone, B. Foote, M. Moncrieff, T. Gal-Chen, W. Cotton, · M. Hjelmfelt, F. Roux, G. Heymsfield, and E. Brandes

25a Radar Observations of Tropical Weather Systems . . . . . . . . . . . . 401 Frank D. Marks, Jr.

25b Tropical Meteorology: Panel Report . . . . . . . . . . . . . . . . . . . . . . . . 426 Edward Zipser, Alan Betts, Frank Ruggiero, and Barry Hinton

26a Organization and Internal Structure of Synoptic and Mesoscale Precipitation Systems in Midlatitudes . . . . . . . . . . . . . . . . . . . . . . 433

K.A. Browning 26b Mesoscale Organization and Processes: Panel Report . . . . . . . . . 461

David B. Parsons, Bradley F. Smull, and Douglas K. Lilly Appendix: Notes on the Physical Mechanisms of Mesoscale Precipitation Bands, Kerry A. Emanuel

27a Radar Research on the Atmospheric Boundary Layer . . . . . . . . . 477 Earl E. Gossard

27b The Atmospheric Boundary Layer: Panel Report . . . . . . . . . . . . . 528 Robert A. Kropfli

28a Radar Observations of the Free Atmosphere: Structure and Dynamics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 534

Kenneth S. Gage 28b Radar Observations of the Free Atmosphere: Panel Report 566

W.H. Hooke

III. OPERATIONAL APPLICATIONS

29a Precipitation Measurement and Hydrology . . . . . . . . . . . . . . . . . . 5 77 Jiirg Joss and Albert Waldvogel -

Appendix A: Radar Data Processing and Short-Period Forecasting in the United Kingdom, C.G. Collier

29b Precipitation Measurement and Hydrology: Panel Report . . . . . 607 Paul L. Smith

30a Severe Thunderstorm Detection by Radar Donald W. Burgess and Leslie R. Lemon

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30b Severe Storm Detection: Panel Report . . . . . . . . . . . . . . . . . . . . . . 648 Joseph H. Golden

31a The Application of Weather Radar to Aviation Meteorology . . . 65 7 T. Theodore Fujita and John McCarthy

31b Aviation Meteorology: Panel Report . . . . . . . . . . . . . . . . . . . . . . . 682 James Wilson

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 689 Current Addresses of Contributors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 777

Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 781

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Preface

This volume, dedicated to the memory of Professor Louis J. Battan, had its origin in the 40th Anniversary Radar Meteorology Conference, which took place in Boston on 9-13 November 1987. The conference commemorated the anniversary of the first radar conference held at the Mas­sachusetts Institute of Technology on 14 March 1947. A tribute to Professor Battan follows this preface.

After four and a half decades from the beginning of radar in World War II, those of us nearing the end of our careers thought it would be useful to look back and doc­ument from whence we came, to take stock of the advances which have been made since then, and to exploit our joint wisdom in setting the agenda for the future. In accordance with these goals, both the conference and this volume were organized in three broad segments: history, critical reviews of progress and status, and panel reports providing a broader perspective and a look into the future.

The histories (Chapters 1-18) cover the people, events and institutions that played pivotal roles during the first two decades of radar studies. In some cases the institutional and national histories bring us up to the present time. Re­grettably, a report was not available from the Soviet Union, where seminal work was done from the late 1940s.

The reviews in Chapters 19 through 31 cover techno­logical, scientific and operational topics. These were writ­ten by experts in each of the subject areas. Following each review is a panel report on the same subject. The latter, authored by one or more scientists, represents a broad consensus of a group of specialists who met in advance of the conference to critique preliminary versions of the re­views and subsequently prepared a report aimed at pro­viding a balanced view, filling in gaps, and identifying avenues of the most promising research and development for the decades ahead.

Altogether the work involved more than 200 participants and authors. The volume is therefore literally a product of the entire community and represents a compendium of knowledge in this field that is not likely to be replicated for many years. It will be of value to students, scientists and technologists, and members of the operational com­munities. It will also serve as a guidebook to decision makers.

A glance at the Table of Contents will show that this book is not a provincial treatise on radar meteorology. Al­though the technological chapters deal explicitly with var­ious aspects of the instruments, the remaining chapters discuss a broad spectrum of scientific and operational problems in meteorology. In this sense the reviews and panel reports are problem oriented. Indeed, in most cases radar is treated as only one of the required tools. The papers cover scientific subjects ranging from cloud microphysics and dynamics to aspects of global climate, and operational

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topics such as nowcasting, severe storm detection, and hazards to aviation such as low-level wind shear. Radar has led the way in remote sensing of the atmosphere and its applications span virtually the entire discipline. More­over, its use continues to expand as the dream of putting weather radar in space approaches reality. At the same time, the impressive technological advances in this and related fields provide further assurance that exciting pro­gress will continue. The chapters on the technology of sig­nal processing, polarimetry, air and spacebome radar, and wind profiling systems are illustrative of the latest devel­opments and trends and point to future system designs.

One of my goals as editor was to provide some sort of synthesis. I tried to do this mainly through the cross-ref­erencing among the various chapters, the reduction of re­dundancy, the filling of significant gaps, and the resolution of conflicts where desirable. In some cases, I deliberately left conflicting ideas to depict the controversy that sur­rounds a particular subject. For example, in several papers about polarization diversity, opinion is divided as to whether or not measurements of differential reflectivity will enhance the accuracy of radar measurements of rain­fall. I also retained many overlapping references to NEXRAD (Next Generation Weather Radar) because they provide differing viewpoints as to how this radar may best be used in addressing the various problems.

With minor exceptions related to format and organiza­tion, I made no attempt to standardize writing style. Thus, each chapter has its own distinct flavor depending upon the style of the author.

The book is especially timely since the field is about to explode with the forthcoming widespread installation of the most modem Doppler radars throughout the United States. These include the Next Generation Weather Radar, UHF and VHF wind profiling radars, and Terminal Doppler Weather Radars for wind shear detection. In Western Eu­rope modem weather radars are being integrated into a cooperative network. New operational and research sys­tems have been installed in Germany, Spain, Italy, Japan and the People's Republic of China, among others. The airborne Doppler radars operated by the National Oceanic and Atmospheric Administration in the United States have produced dramatic research results and have stimulated the development of new airborne systems both in the United States and France. Also, the emerging plans to place rain-measuring radars on satellites promise unprecedented observational capabilities.

These initiatives are already creating a demand for a new generation of broadly based researchers· with ad­vanced skills in the radar arts and for operational meteo­rologists-capable of exploiting the modem technology. We expect that this compendium will contribute strongly to-

ward these ends. The large number of new systems will also increase the amount of observational data by several orders of magnitude in the next decade, thereby providing a very rich source of new material to the science community which will surely lead to new insights and discoveries.

When viewed in the context of the striking advances taking place in parallel fields of space observations, com­puter technology, communications, information handling and display, and numerical modeling of meteorological and oceanic phenomena, the outlook for the future is breathtaking. The existing activities under the World Cli­mate Research Program, the emerging activities for study­ing atmosphere-oceans-land as an integrated system, and the rich variety of planned and ongoing experiments on storm and mesoscale problems provide the stage on which much of the research and operational activity will be played out.

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The one discouraging factor in this otherwise exciting picture is the failure of our universities to train adequate numbers of scientists in the instrumental and observational aspects of meteorology in order to meet future needs. We hope that this volume will help to stimulate the academic community to rectify this situation.

While this book and the conference from which it grew have dominated the last three years of my life, I am grat­ified by how much I have learned, by the satisfaction of having participated in setting the foundations for the fu­ture, and the exquisite joy of seeing how far we have come since I started on the road of radar in meteorology 45 years ago.

David Atlas Editor

Acknowledgments

The Battan Memorial and 40th Anniversary Conference of Radar Meteorology and this volume were made possible in part through the generous support of the following agencies:

National Science Foundation National Aeronautics and Space Administration National Oceanic and Atmospheric Administration Office of Naval Research U.S. Air Force Office of Scientific Research

The Air Force Geophysics Laboratory (Hanscom Field) was also particularly gracious in supporting the conference travel of many senior scientists who had previously been associated with its Weather Radar Branch either as staff members or grantees. This combined support permitted the participation of many persons who would not other­wise have been able to attend the conference. The staff of the AFGL Weather Radar Facility and its associated con­tractors were also instrumental in all the activities before, during and after the conference, and in the preparation of this volume.

We are also indebted to the following firms for contri­butions to assist the conduct of the conference:

Aeromet, Inc. Alden Electronics Enterprise Electronics Raytheon Company SigmetjLassen Research Tycho Technology

We particularly appreciate the additional support of UNISYS in subsidizing the book's dust jacket, and of NCAR in providing the striking radar photos for the front and back covers.

We are especially grateful to Richard E. Carbone who was Chairman of the AMS Committee on Radar Meteo­rology through most of the period involved, the Confer...: ence Organizing Committee, and the Local Arrangements Committee. Members of these committees are listed below.

One of the highlights of the conference was an exhibit of "Radar as Art," arranged through the voluntary assis­tance of Dr. Harold Baynton and Linda Carbone, with the support of NCAR. The National Center for Atmospheric Research was also instrumental in providing arrangements and facilities for the advance meetings of the panels.

The success of the conference was due in large part to the dedicated efforts of Dr. Alan Bohne of AFGL, Chair­man of the Local Arrangements Committee, who looked after the myriad of details. The unique structure of the conference and the social functions posed novel challenges to Alan and his colleagues, Paul Desrochers and Don Ha-

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mann of ST Systems (STX) Corporation and Frank Rug­giero of AFGL, all of whom exerted themselves above and beyond normal expectations. Albert Chmela (AFGL, re­tired) arranged the nostalgic "Old Timers" evening. The fun of the mock awards ceremony was due largely to the preparation of cartoons by Dr. Ronald Rinehart of the University of North Dakota, aided by an anonymous com­mittee of three who created the awards, and by Harriet Chmela who arranged appropriate music. Denny Donald­son's enthusiastic guidance to the many interesting sights of Boston made the meeting particularly enjoyable for the spouses.

A notable and poignant contribution was made by Prof. Philip Krider, on behalf of the Institute of Atmospheric Physics, University of Arizona, in the form of a bound collection of the works of Lou Battan which was presented to Jeanette Battan during the conference. Lou's daughter, Suzette, had spent several months painstakingly sifting through his papers and assembling them.

The lion's share of acknowledgments must go to the authors of the histories and critical review papers, without whom neither the conference nor this volume would have been possible. We also owe deep thanks to the many panel members and the panel chairman who did so much to stimulate interest and to round out this treatise. Dr. Robert J. Serafin of NCAR was most helpful, especially in orga­nizing the technological sessions and reviews. Pauline Austin, former director of the MIT Weather Radar Project, assisted importantly as a reviewer of several manuscripts.

I am most grateful to Donna Velardi of AFGL who typed the voluminous announcements and correspondence con­nected with the conference as well as a number of the manuscripts, and to Shelley Zucker, Carol Nicolaidis, Vic­toria Holzhauer and Regina Gregory of NCAR for prep­aration of the unified reference list. The attractive dust jacket is due to the professional service volunteered by Helga Hardy. Mrs. Quy Philpot of Centel Federal Services Corporation, supported by NASA, also performed yeoman services during the final stages of preparation of the book.

I am also pleased to acknowledge the immense, first­rate job of copy editing done by Laura Westlund and the technical editing by Dr. Harold Nagel, both of the Amer­ican Meteorological Society. Also, Executive Director Emeritus Kenneth Spengler and Evelyn Mazur guided us wisely through the entire process.

My deepest personal appreciation goes to Ralph J. Don­aldson of STX Corporation (working with the AFGL Weather Radar Facility), my friend and colleague of about 40 years, and my faithful, imaginative and dedicated co­chairman of the conference. Ralph also took the initiative to edit a number of the manuscripts and advised me on many others. Without his continuing help and encourage-

ment this work could not have been accomplished nearly so well.

Finally, I must thank my wife Lucille, who assisted me throughout this project. Her understanding and love have supported all my endeavors.

AMS 1987 COMMITTEE ON RADAR METEOROLOGY

Richard Carbone, Chairman Kenneth Gage David Jorgensen Jacques Testud Albert Waldvogel

Edward Brandes Joseph Golden Frank Marks Carlton Ulbrich

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PROGRAM COMMITTEE

David Atlas, Co-Chairman Richard Carbone Kerry Emanuel Kenneth Gage Richard Passarelli Robert Abbey

Richard Doviak Ralph Donaldson,

Co-Chairman Kenneth Glover Roddy Rogers

LOCAL ARRANGEMENTS COMMITTEE

Alan Bohne, Chairman Denny Donaldson Ian Harris Ronald Rinehart

Albert Chmela Spiros Geotis Lou McNally

Tribute to Professor Louis J. Hattan

Dr. Louis J. Battan died on October 29, 1986, after a short illness. Although he had been a professor of atmo­spheric sciences at the University of Arizona since 1958 and director of the Institute of Atmospheric Physics there from 1973 to 1982 (and associate director from 1958 to 1973), his activities on the national and international scenes were so varied that he was known in different ways by the numerous communities with which he was in­volved. However, all who knew him shared his uncom­monly good humor, took pride in his friendship, and re­spected his wisdom and good judgment. Lou is survived by his wife Jeanette, daughter Suzette, and son Paul.

Battan was born in New York City on February 9, 1923. He was the second of four sons born to Annibale and Luisa Battan, immigrants to the United States from the village of Vigo in the Tyrolean Alps of Austria. He grew up in Brooklyn, New York, in a family environment that encouraged the highest moral standards and a devotion to hard work and self-reliance, qualities that remained with him throughout his life.

Lou began college as a mechanical engineering major at the City College of New York in 1941. Sometime during this period, he took and passed the examination for the New York City Fire Department, thinking that this would be useful as a fall back position. A World War II recruiting poster brought him into the Army Air Corps aviation cadet program in meteorology. I met him on the New York sub­way on March 8, 1943, as we were both beginning our service with 15 months of study at New York University (NYU) . Matching the name on my suitcase to the first name on the list of his Army orders assigning us to NYU, Lou introduced himself, and in the short walk from the station to the University Heights campus, we decided to room together if permitted. Thus began 43 years of friend­ship and two careers in meteorology. From March 8, 1943, until we received our commissions on June 5, 1944, we lived, studied, and marched together. Indeed, we probably would have been together anyway because of the Army's penchant for conducting business in alphabetical order.

Our days of meteorological training at NYU were any­thing but easy. In fact, our instructors were so tough on us that we often regarded them as the enemy. Little did we realize that at least four of them were to become cher­ished friends and greats in meteorology-Hans Panofsky (Pennsylvania State University, University Park), Yale Mintz (University of California, Los Angeles), Bob Fleagle (University of Washington, Seattle), and Bill Gordon (Rice University, Houston, Texas).

Lou, a devout Catholic, set the moral tone for the eight of us who occupied the apartment at 1950 Andrews Av­enue adjacent to the campus. To be sure, he was not the most conscientious soldier in the class, but when it came

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to studies he was unbeatable. I remember many an evening in the summer of 1943 when he and Dave Lowenthal (now at Boston College, Boston, Massachusetts) sat on the fire escape testing one another in preparation for our daily quiz. This kind of discipline rubbed off on others in the apartment, so it was more than coincidental that the three of us ended in the top ten at graduation. Following our commissioning as second lieutenants, we three were also selected to go on to radar school at Harvard University and the Massachusetts Institute of Technology (MIT; both in Cambridge, Massachusetts).

The intensity of the NYU meteorology program was only a faint foreshadow of what we were to endure in nine months of radar training at Harvard and MIT. It is no exaggeration that those few months equalled about two years of peacetime education in radio engineering. Sur­prisingly, we retained much of what we were taught. Al­though we did not appreciate it at the time, we were among the privileged "100" weather officers who were also trained in radar. This group was the cadre that then went out into the field to set up and operate the SCR-584s for wind finding and the APQ-13s for both ground-based storm detection and airborne weather reconnaissance. While only three of us remained in what was to become radar mete­orology, it became clear some years later that this dual disciplinary training was responsible for our innovative abilities. This lesson deserves to be reemphasized now, when we are beginning to have doubts about the source of the next generation of instrumentally oriented meteo-

rologists. After radar school, Lou went on to set up a weather radar at Panama City (Eglin Field), Florida, and was later stationed at bases in Texas, Arizona, and Puerto Rico.

Upon his discharge from active duty in 1946, Lou re­turned to NYU and obtained his B.S. degree in meteorol­ogy. He joined the U.S. Weather Bureau and was then assigned to the Thunderstorm Project at the University of Chicago. He earned his M.S. degree there in 1949.

With the end of the war, a number of the leaders of meteorology recognized the unprecedented opportunity to attack one of the great hazards to flight safety-the thunderstorm-by using Second World War technology, mainly aircraft and radar. With the eager cooperation of the Air Corps and the U.S. Weather Bureau, the Thun­derstorm Project was born. Two field programs were car­ried out. The first was centered around Pinecastle near Orlando, Florida, in 1946, and the second was near Wil­mington, Ohio, in 1947. Clinton County Air Force Base in Wilmington was the home of the All Weather Flying Di­vision, where I remained as a civilian scientist after my own discharge from the Army. It was there that Lou and I were again brought together during the second field phase of the Thunderstorm Project.

The Thunderstorm Project was the prototype of the large-scale field experiments that became increasingly common in the postwar years. It was unique in many ways, most importantly, perhaps, in the coordinated use of radar, an extensive ground network of meteorological stations, and storm-penetrating P-61 "Black Widow" aircraft. The project produced a quantum jump in our knowledge of thunderstorms, but there was much more to come in later years. "The Thunderstorm," the report that resulted from the project (by Horace Byers and Roscoe Braham of the University of Chicago, with contributions by Lou and oth­ers), remains a classic today, although some of the concepts put forth there have since been elaborated (Byers and Bra­ham, 1949).

Lou left the Weather Bureau in 1951 but remained at the University of Chicago, completing his Ph.D. in 1953 and serving on the faculty until 1958. His dissertation, "Observations on the Formation of Precipitation in Con­vective Clouds," was based upon TPS-10 radar data from the 1947 phase of the Thunderstorm Project. Braham counts this work as the first definitive identification of the coalescence mode of precipitation growth in warm con­vective clouds. Subsequently, these findings were con­firmed by studies in Puerto Rico, the central United States, and Arizona. It was during this period that Battan worked with Byers and Braham on the artificial nucleation of cu­mulus clouds, and the triumvirate became known as the "three B's" in the cloud physics community. Some of this appears in the paper by the three B's that appeared in 1957 (Braham et al., 1957).

Lou, fluent in Italian and Spanish since childhood, stud­ied French and German for his Ph.D. language

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ments. Later, he also studied Russian, motivated by the accelerating activities in weather modification in the Soviet Union. He subsequently served on several U.S. delegations to the Soviet Union and utilized this talent to write anum­ber of review papers on the state of Soviet cloud physics, weather modification, and radar meteorology. These ac­tivities helped establish him as the world expert on Soviet research in these realms.

Lou was catapulted to the forefront of the field of weather modification research as a result of his personal expertise in this area and his deep familiarity with similar work in the Soviet Union. He thus played an active role in writing the 1973 National Academy of Sciences report on the subject. Subsequently, he served on many weather modification advisory groups.

In 1958, Lou joined the faculty of the University of Ar­izona as Associate Director of the Institute of Atmospheric Physics and Professor of Meteorology. During his early years at the University of Arizona, Lou and Professor Dick Kassander, his fellow associate director of the institute, led a seven-year randomized cloud seeding program that be­came a model for the design of many other weather mod­ification programs. In 1973, he was appointed Head of the Department of Atmospheric Sciences and Director of the Institute of Atmospheric Physics, posts he held until1982. Dick Kassander recalls the many times he found himself drowning and depressed under the ever-increasing load of paperwork. He writes, "Lou would come in, note the situation, and with a big grin, he'd stretch out his long arms and carry it all away. In short order, he would be back with a few pieces of paper to replace the previous mess." Indeed, Lou's administrative and organizational skills were quickly recognized and called upon frequently. Lou remained an active member of the department and institute until his death.

It was to the area of radar meteorology that Lou would devote a good deal of his time and energies. One of the main themes of this research was the radar backscatter from hail, first in collaboration with Ben Herman (now at the University of Arizona, Tucson) in the 1960s and, more recently, with Craig Bohren, now at Pennsylvania State University. In this regard, it was a curious coincidence that brought our scientific paths together again in 1959. Let me set down this part of the story in Lou's own words, which he tape-recorded for me on October 8, just three weeks before his death.

You asked about the Herman and Browning work, and I must say that was a very exciting time. The history of that work on the backscattering from hail started this way. Ben Herman, who was then a graduate student, was working on the scattering of infrared radiation by cloud droplets. He had programmed the Mie scattering equations and came walking into my office one day and said that he had this program and did I see any useful applications. This was the German

time [1959] you were working in England with Frank Ludlam and I had gotten a letter from you saying that you had gotten some exciting results, that the backscatter cross sections of large hail [actually, deep frozen artificial ice balls] were much larger than you expected. So I said to Ben, "Yeah, let's run off some backscatter calculations for spherical ice particles which simulate hailstones at microwaves." Shortly thereafter, back came the calculations showing the curves that I sent you. And I must say, it was one of the big thrills of my scientific experience when I got your letter in which you had plotted your actual measurements against the curve. Ire­member thinking to myself: Isn't this astounding, theory and measurements are in agreement.

Well, that thrill was occurring simultaneously on both sides of the Atlantic. It was not only that theory and mea­surement agreed so well, but we all had nurtured the Ray­leigh scatter law that said that (small) ice particles scattered about one-fifth as well as equal water drops. Until then the entire radar meteorology community had either for­gotten or ignored the 1941 work of Ryde (1946), which showed that spheres of ice became better scatterers than those of water at diameters greater than about 0.6 wave­lengths.

The thrill of discovery and serendipitous confluence of separately derived ideas punctuate much of science. Theory and experiment done 6000 miles (10 000 km) apart co­alesced and motivated Lou to extend the Arizona calcu­lations to melting and spongy ice spheres over a range of wavelengths. He continued this work on and off until his death. It is notable that five of his last six papers dealt with the scattering properties of hail and snow. His last paper, on the backscatter of large oblate spongy hail, was published in 1987 (Longtin et al., 1987).

The other realm in which Lou pioneered was Doppler radar. In his taped comments of October 8, 1986, he told me that the papers that stimulated his interest in Doppler were those by Boyenval (1960) and Lhermitte (1960), both of which were presented at the Eighth Conference on Ra­dar Meteorology in San Francisco, California, in 1960. In short order, he, Dick Kassander, and John Theiss (then at the University of Arizona) submitted a proposal to the National Science Foundation to develop a 3-cm Doppler radar, and their first paper on the vertical motions and particle sizes in thunderstorms appeared in 1964 ( Battan et al., 1964). His scientific interests then fluctuated between weather modification, Doppler radar, and the scattering properties of hydrometeors.

I suspect that Lou would prefer to be remembered most, and probably will be, for his books, of which there were 16. Most of these have been translated into several lan­guages. His first book, Radar Meteorology ( Battan, 1959), was a concise and lucid introduction to the subject. This was updated and enlarged by Radar Observations of the Atmosphere (Battan, 1973). Except for one text in Russian and another in French, and my own more modest mono­graph in 1964, these books remained the major treatments

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of the subject until the appearance of Doppler Radar and Weather Observations by Doviak and Zrnic (1984). He also wrote and coauthored elementary texts such as Weather ( Battan, 1984) and Fundamentals of Meteorology ( Battan, 1983a). Lou also wrote seven other popular books, ranging from The Nature of Violent Storms (Battan, 1961) to Weather in Your Life ( Battan, 1983b). These are important because of their straightforward style and the ease with which they conveyed abstract concepts. Accordingly, they attracted a wide spectrum of students and nonspecialists who might have been frightened off by the more esoteric treatments.

One can hardly estimate the impact that Lou's popular books and introductory texts have had on the atmospheric sciences and on society through the attraction of students to the field and through contributions to the public's un­derstanding of science worldwide. Certainly, his contri­bution on these scores is second to none in meteorology.

Lou used his talent for writing in conjunction with his research abilities to produce a large number of other pub­lications as well. Beginning with the journal article "The Use of Radar in Determining the Amount of Rain Falling over a Small Area" (Battan, 1948), he produced over 100 scientific papers and reports and an additional 100 pub­lished items in encyclopedias, periodicals, and newspapers. In spite of his extensive achievements as a scientist and a scholar, however, he maintained a modest posture throughout his career.

With this record of accomplishments, one might have expected Lou to have taken some high post in government or academia. Indeed, he could have, for he had received many such offers. To be sure, he was tempted on occasion by positions from which he could exert great influence. However, Lou had found his niche as university professor and writer. He was comfortable with himself, the ways in which he could contribute, his position, and his family. Because of this inner peace and satisfaction, he could be called upon for advice unimpeded by ulterior motives.

Lou did not isolate himself in his comfortable niche, however. Indeed, he was called upon time and again to serve the national and international geophysical commu­nities. He was a member of several early delegations to the World Meteorological Organization and the Soviet Union. He served with distinction on a long list of com­mittees and panels of the National Academy of Sciences, including the chairman of the Committee on Atmospheric Sciences (1973-76) and vice-chairman of the Geophysics Study Committee (1978-82) as well as the National Ad­visory Committee on Oceans and Atmosphere (1978-81). Lou was also extremely influential in the founding of the National Center for Atmospheric Research (NCAR). He served NCAR and its operating corporation, the University Corporation for Atmospheric Research, in many ways, in­cluding long-time service on the Board of Trustees and the Members' Representative Group, and in many advisory capacities. He fought staunchly to permit scientists to guide their own fates without undue direction from above, be-

lieving that the best science nearly always is done in an unfettered, supportive atmosphere.

Lou was also an active leader in the affairs of both the American Geophysical Union and the American Meteo­rological Society. In AGU, he served on a variety of com­mittees and was president of the Meteorology Section (1974-76). He was also chairman of the U.S. National Committee of the International Association on Geodesy and Geophysics (1980-84). He was also slated to be the AGU Foreign Secretary when he took ill. On at least two occasions, he declined nominations for the AGU presi­dency.

His activities in the American Meteorological Society (AMS) are legend. They included service on a host of sci­entific and advisory committees, the presidency (1966-67}, chairman of the Commission on Scientific and Tech­nological Activities (1970-73), and chairman of the Plan­ning Commission for 12 years.

Many of his contributions to meteorology were recog­nized by the AMS. In 1962, he received the Meisinger Award "for his outstanding, imaginative and pioneering research in radar meteorology and in cloud physics"; in 1971, the Charles Franklin Brooks Award for Outstanding Services to the Society "in recognition and appreciation for his imaginative, wise, and good-humored leadership during many years of service as Councilor and President of the Society"; and in 1975, the Second Half Century Award "for his many contributions to cloud physics and his objective scientific evaluation of weather modification efforts, his writings fostering public understanding of me­teorology, and his greater service to the profession in many capacities." His daughter Suzette told me that he was es­pecially proud of his election as an honorary member of the AMS in early October 1986, just a few weeks before his death.

References

Battan, L.J., 1959: Radar Meteorology. University of Chicago Press.

--, 1961: The Nature of Violent Storms. Doubleday.

--, 1973: Radar Observations of the Atmosphere. Univer-sity of Chicago Press.

--, 1983a: Fundamentals of Meteorology. 2nd ed., Pren­tice-Hall.

--, 1983b: Weather in Your Life. W.H. Freeman.

xvi

On the personal side, Lou was a raconteur of great note. He could often be found at the center of a group, recasting a story of passing humor into one that elicited great laugh­ter. His sense of humor stood him in good stead in many other more serious circumstances by helping to relieve the tension. In addition, his colleague, Ben Herman, writes that Lou was the wise old sage of the department to whom everyone went for advice, consolation, and encourage­ment.

Perhaps his greatest attribute is that Lou was a gentle person. He was thoughtful, kind, and sensitive. Never did he utter a denigrating word about anyone; conversely, no one had an unkind word to say about him. He was admired and respected by all, many were proud to be numbered among his friends, and others, like me, loved him as a brother.

The combination of his science, his writings, his states­manship, and the esteem in which he is held constitute a legacy that few of us can hope to match.

0 may I join the choir invisible Of those immortal dead who live again In minds made better by their presence

David Atlas*

-George Eliot "0 May I Join the Choir Invisible"

Department of Meteorology, University of Maryland

Reprinted from Eos, Vol. 68, 656 and 676.

• Presently, independent consultant, Bethesda, Maryland.

--, 1984: Weather. 2nd ed., Prentice-Hall.

--, J.B. Theiss and A.R. Kassander, Jr., 1964: Some Doppler radar observations of a decaying thunderstorm. Proc. 11th Weather Radar Conf., Boulder, Amer. Meteor. Soc., 362-365.

Boyenval, E.H., 1959: Echoes from precipitation using pulsed Doppler radar. Proc. Eighth Conf. on Radar Me­teorology, San Francisco, Amer. Meteor. Soc., 57-64.

Braham, R.R., Jr., L.J. Battan and H.R. Byers, 1957: The artificial nucleation of cumulus clouds. Meteor. Monogr.; Amer. Meteor. Soc., 2, 47.

Byers, H.R., and R.R. Braham, Jr., 1949: The thunderstorm. Rep. NTIS PB 234515, U.S. Dept. of Commerce, Wash­ington DC.

--, et al., 1948: The use of radar in determining the amount of rain falling over a small area. Eos Trans. AGU, 29, 187-196.

Doviak, R.J., and D.S. Zrnic, 1984: Doppler Radar and Weather Observations. Academic Press.

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Lhermitte, R.M., 1959: The use of special "pulsed Doppler radar" in measurements of particle fall velocities. Proc. Eighth Conf. on Radar Meteorology, San Francisco, Amer. Meteor. Soc., 269-275.

Longtin, D.R., C.F. Bohren and L.J. Battan, 1987: Radar backscattering by large, spongy, ice oblate spheroids. J. Atmos. Oceanic Techno/., 4, 355-358.

Ryde, J.W., 1946: Attenuation of centimeter radio waves and the echo intensities resulting from atmospheric phenomena. J. Inst. Electr. Eng. London, 3A, 93, 101.