Meteorology was first considered in Landolt-Börnstein in Volume III (published 1952) of the 6th Edition. At that time, nine contributions with 153 pages seemed enough. In the meantime, meteorology has experienced a worldwide boom owing to the growing interest in environmental problems. New observation and evaluation methods together with high performance computers have produced an ever increasing amount of data on the atmosphere, which are being exploited for weather and climate problems in various ways. In addition to the improved knowledge gained directly by these observations they are indispensable in the verification of the diagnosed and predicted atmospheric states obtained by mathematically based weather forecasting and climate models. Volume V/4 of the New Series covers the field of meteorology as the physics of the atmosphere in several subvolumes. The first, V/4 a 'Thermodynamical and dynamical structures of the global atmosphere', appeared in 1986. It was followed by subvolume V/4 b dealing with the physical and chemical data of the atmosphere. Subvolume V/4 c is concerned with the physical and meteorological aspects of climate. The first part, V/4 c 1, presented here, contains contributions on climate definition, specific surfaces climates, climate variations, and the planetary boundary layer. The second part, V/4 c 2, will treat the present global surface climate and the mathematical and physical concepts of climate modelling.