Aeroclimatology

the study of climatological conditions in the free atmosphere—that is, in atmospheric layers located at various levels above the earth’s surface. In practice this means the troposphere and the lower stratosphere (up to altitudes of 20–25 km). Aeroclimatological studies occasionally deal with higher layers, including those up to the mesosphere.

Aeroclimatology is a part of climatology, along with a number of other meteorological disciplines. Aeroclimatology came into being in the mid-20th century, when the development of aerological observations provided sufficient material for statistical generalizations concerning the state of the upper layers of the atmosphere. Conclusions today may be reached on the basis of observations which have gone on for three or four decades and have covered the significant areas of the globe. For such regions as Antarctica a briefer series of observations is sufficient. The basic material of aeroclimatological work is formed by the results of ascents (soundings), carried out by a vast radiosonde network and an even vaster pilot-balloon network of stations. Some role is played by airplane soundings (for special purposes). In order to learn more about the climate regime of the highest layers, the results of rocket soundings are also used.

Aeroclimatological studies consist in the empirical discovery and theoretical explanation of the three-dimensional distribution and annual course of the basic meteorological elements. Subjects studied are the average topography over several years of isobaric surfaces, representing a three-dimensional baric atmospheric field and also the distribution of the sources of heat and cold within it; the statistical characteristics of the wind regime at isobaric surfaces or at standard levels; the average distribution over several years of air temperature at isobaric surfaces or at standard levels and other statistical characteristics of a long-term temperature regime (as particular problems—the system of temperature inversions and characteristics of the tropopause); the analogous long-term regime of specific and relative air humidity (a particular problem is the condition of airplane icing); and cloud systems (the repetitive nature of cloud forms and altitudes as well as the average altitudes of clouds). The statistical conclusions of aeroclimatology are presented in the form of numerical tables, charts, and vertical profiles of the atmosphere. Most of these aeroclimatological operations are carried out on a global scale or for the northern hemisphere, the continents, or such territories as those of the USSR, the USA, and other large countries. Aeroclimatological characteristics are also compiled for specific points. The data provided by aeroclimatology makes possible the compilation of a three-dimensional picture of the general circulation of the atmosphere as well as the temperature and moisture-containing systems associated with it over the entire globe. Aeroclimatological conclusions also have a direct importance in ensuring the operations of air transport.

In the USSR problems of aeroclimatology are studied by the Scientific Research Institute of Aeroclimatology of the Hydrometeorological Service in Moscow (NIIAK) as well as by a number of other institutes. At NIIAK extensive studies are conducted on global aeroclimatological observations, and machine technology is utilized. Such studies are summed up in atlases and monographs. Analogous research is being carried out at several institutes under the jurisdiction of foreign meteorological services, especially in the USA, the Federal Republic of Germany, and Great Britain.