Convective motions in a free atmosphere

Description

This book describes the methods and results of investigations of convective motions in a free atmosphere and in clouds, and the equipment necessary for their measurement. The theory of the statistical interpretation of the observed results is given, since the interpretation of these data permits the establishment of the basic parameters of convection in the atmosphere, and shows the dependence of these parameters on various physicogeographical conditions. These factors, in turn, clarify the way in which convective motions develop in the atmosphere, and the relation between convective motions outside and inside clouds. In addition, the results may be used as quantitative descriptions of certain phenomena caused by convection or related to it. The book may be of interest to scientists in the field of atmospheric physics and in other fields (e.g., aviation, propagation of various radiations, air pollution) in which these data are used. The book may also be useful to students at meteorological institutes and university physics faculties. PREFACE . vii INTRODUCTION . 1 Chapter I. A METHOD FOR STUDYING CONVECTIVE MOTIONS IN A FREE ATMOSPHERE. . 1. The physical foundations of the method. 2. Airplane thermometric equipment 12 3. Measurement errors 22 4. Verification of the method . 25 5. The technique of the flight and the primary processing of the measurements 30 6. Measurements in clouds 32 7. A method for studying descending currents around developing cumulus clouds 38 Chapter II. STATISTICAL INTERPRETATION OF THE MEASUREMENT RESULTS . 45 1. Formulation of the problem . . 45 2 Distribution of convective currents according to their real dimensions and concentrations of convective currents . 46 3. The relative area and relative volume of ascending currents . . . 50 4. Case of wind varying with height 53 5. Distribution of convective currents according to their dimen- sions and temperatures at their centers 54 6. Generalization of the solutions to the case of n independent variables . 57 7. Average temperatures at the centers of convective currents . 58 8. Equilibrium cases 60 9. The method and accuracy of the calculations 61 Chapter III. CONVECTIVE MOTIONS IN A FREE ATMOSPHERE 67 1. Atmospheric conditions during the measurements 67 2. Temperature profile of convective currents . 70 3. Preparation of the experimental data for calculations 71 4. General regularities of convective motions 73 5. Vertical variation of the convection parameters. 80 6. The daily variation of convective motions 92 7. The dependence of convection parameters on the degree of atmospheric instability . 102 8. Dependence of the convection parameters on the nature of the underlying surface 108 9, The clearing-up mechanism of instability in a free atmosphere . 121 10. Temperature and velocity of ascending currents. 126 11, A hydrodynamical model of convective motions in an unstable atmospheric layer. 129 12. The form of ascending currents in the atmosphere 133 Chapter IV. CONVECTIVE MOTIONS IN CUMULUS CLOUDS 136 1. Conditions of measurements and character of flights 136 2. The temperature profile of convective currents in clouds 140 3. General regularities of convective motions in thick cumulus clouds . 141 4. Vertical variation of the convection parameters in clouds . 145 3. Dimensions, temperature and velocity of ascending currents in thick cumulus clouds 153 6. Descending currents caused by developing cumulus clouds . 155 7. The relation between convective motions in the atmosphere and the formation and development of cumulus clouds . 161 APPENDIX . . 172 A. The humidity of ascending convective currents . 172 B. Nonuniformities in the atmospheric refractive index in the range of radiofrequencies due to convective motions 174 TABLES . 179 BIBLIOGRAPHY 182