Foreword 



This volume brings together the work done in radio meteorology 

 over the past ten years at the National Bureau of Standards' Central 

 Radio Propagation Laboratory (CRPL). This decade has seen the 

 development, on an international scale, of great emphasis upon the effects 

 of the lower atmosphere on the propagation of radio waves. The CRPL 

 group has concentrated upon the refraction of radio waves as well as the 

 refractive index structure of the lower atmosphere on both synoptic and 

 climatic scales. These are the areas of radio meteorology that are treated 

 in this volume, with additional chapters on radio-meteorological param- 

 eters and the absorption of radio waves by the various constituents of the 

 lower atmosphere. An effort has been made to include results obtained 

 in other laboratories both in the United States and abroad. 



A. V. AsTiN, Director. 



