ADVANCES I N GEOPHYSICS VOLUME I1 This Page intentionally left blank Advances in GEOPHYSICS EDITED BY H . E. L A N D S B E R G U.S. Weather Bureau Washington, D. C. EDITORIAL ADVISORY COMMITTEE Bernhard Haurwitz Walter D. Lambert James B. Macelwane, S. J. Roger Revelle VOLUME 2 1955 ACADEMIC PRESS INC., PUBLISHERS NEW YORK, N. Y. COPYBIGHT 1966, BY ACADEMIC PRESS INC. 126 East 23rd Street, New York 10, N. Y. All Rights Reserved No part of this book may be reproduced in any form, by photoatat, microfilm, or any other means, without written permhion from the publishers. Library of Congress Catalog Card No. 62-12266 PRINTED IN TEE UNITED STATES OF AMERICA LIST OF CONTRIBUTORS HUGOBENIOFF,Department of Seisnutlogy, California Institute of Technology, Pasadena, California IRVING I. GRINOORTEN, Air Force Cambridge Research Center, Cambridge, Massachusetts K. L. S . GUNN,McGill University, Montreal, Canada WALTER HITSCHFELD, McG'ill University, Montreal, Canada J. LAURENCE KULP,Lamont Geological Observatory (Columbia University), Palisades, New York J. S . MARSHALL, McG'ill University, Montreal, Canada WILLARD J. PIERSON, JR., Department of Meteorology and Oceanography, College of Engineering, New York University, New York, New Yo& This Page intentionally left blank Foreword The first volume of Advances in Geophysics was well received by our colleagues. This encourages us to send this second volume into the world. It is again a collection of articles cutting widely across the various subfields of our science. This diversified contents is presented even though a few reviewers suggested that each of these books treat with progress in one area only. We are clinging, however, to our original aim: We want to acquaint specialists with advances in the neighboring sectors. Our hope is that some cross fertilization might bring forth some new ideas. The topics presented in this volume demonstrate forcefully that new knowledge has been acquired most rapidly in areas where geophysics could take advantage of developments in other sciences. The impact of modern electronics on observing techniques has brought about a scientific revolution. We can fathom this from the two articles dealing with seismometry and radar weather. This last field, curiously enough, owes its existence to an undesired effect on equipment designed for a much less peaceful purpose. The great strides made in atomic isotope techniques have advanced geological timing tremendously as shown in the summary herein. This is certainly only a beginning because isotopic tracers are likely to produce answers to many questions in meteorology, hydrology, and oceanography also. Finally, we can see again, as in parts of Volume I, the role played by modern statistics in geophysical analysis, as shown in the articles on wind-blown waves and objective weather forecasting. As geophysical observations accumulate a t an ever increasing rate, the new statistical keys are likely to open the secrets locked in the mass of data. While this is being written, plans are well under way for a third volume. It will take us to the present physical frontiers of the globe in the Arctic Ice Islands and will include discussions of the long-range terrestrial and extraterrestrial effects on the atmosphere, the optics of the air and its suspensions, the structure of the earth beneath the continents, and the economically so important questions of groundwater. H. E. LANDSBERG February, 1966 vii This Page intentionally left blank Contents LIST OF CONTRIBUTORS . . . . . . . . . . . . . . . . . . . . . . . . . . v FOREWORD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii Advan