ADVANCES IN GEOPHYSICS VOLUME 15 Contributors t o This Volume H. U.D~~~TSCH BIJANESFANDIARI FLOYD A. HUFF CARLA. MOORE DONALD J. WILLIAMS Advances in GEOPHYSICS Edited by H. E. LANDSBERG lnstitute for Fluid Dynamics and Applied Mathematics University of Maryland, College Park, Maryland J. VAN MIEGHEM Royal Belgian Meteorological Institute Uccle, Belgium Editorial Advisory Committee BERNARD HAURWIROGER REVELLE R. STONELEY URHO A. UOTILA VOLUME 15 1971 Academic Press N e w York and London COPYRIGHT Q 1971, BY ACADEMIC PRESS,INC. ALL RIGHTS RESERVED NO PART OF THIS BOOK MAY BE REPRODUCED m ANY FORM, BY PHOTOSTAT, MICROFILM, RETRIEVAL SYSTEM, OR A N Y OTHER MEANS, WITHOUT WRI'ITEN PERMISSION FROM THE PUBLISHERS. ACADEMIC PRESS, INC. 111 Fifth Avenue, New York, N e w York 10003 United Kingdom Edition published by ACADEMIC PRESS, INC. (LONDON) LTD. 24/28 Oval Road, London NW1 IDD LIBRARY OF CONGRESS CATALOO CARD NUMBER:52-12266 PRINTED IN THE UNITED STATES OF AMERICA CONTENTS LIST OF CONTRIBUTORS .......................................... vii Geochemistry and Geology of Helium CARL A. MOORE and BIJAN ESFANDIARI 1 . Introduction ................................................ 2 . Radioactivity ............................................... 3 . Origin and Abundance of Elements ............................ 4 . Origin of Helium ............................................ 5. Helium-Generating Potential of Rocks and Fluids ............... 6. Distribution and Occurrence of Helium ........................ 7 . Migration of Helium ........................................ 8. Accumulation or Entrapment of Helium ....................... 9 . Natural Gas Analysis ........................................ 10. Conclusions................................................. References .................................................... 2 3 9 11 14 29 32 41 46 63 54 Evaluation of Precipitation Records in Weather Modification Experiments FLOYD A. HUFF 1 . Introduction ................................................. 60 2 . Effects of Natural Precipitation Variability in Evaluating Cloud Seeding Experiments ......................................... 64 3. Use of Precipitation Climatology in Assessing Potential Benefits of Weather Modification ......................................... 70 4 . Space and Time Variability Relationships ....................... 78 5 . Other Relevant Climatological Studies .......................... 92 6. Precipitation Measurement Requirements ....................... 97 7. Statistical Evaluation Techniques .............................. 111 8 . Downwind Seeding Effects ................................... 119 9 . Design of a Precipitation Modification Experiment ............... 123 References ..................................................... 133 V vi CONTENTS Charged Particles Trapped in the Earth’s Magnetic Field DONALD J . WILLIAMS 1 . Introduction ................................................. 2. Magnetic Field Considerations ................................. 3. Particle Survey .............................................. 4 . Sources. Losses. and Transport ................................ 5 . Concluding Remarks and Future Directions ...................... List of Symbols ................................................ References ..................................................... 137 146 156 170 206 207 208 Photochemistry of Atmospheric Ozone H . U . DUTSOH 1 . Observed Distribution of Total Ozone ........................... 2. The Classical Photochemical Theory: “ Pure Oxygen Atmosphere ” . 3. Ozone Photo