178 AIR MASS ANALYSIS 
H.—METEOROLOGY OF THE FRICTION LAYER 
1. Turbulence 
2. Surface Temperature Influences 
3. Mountain Meteorology 
4. Micro-Aerological Analysis and Microclimatology 
Except for some purely theoretical items in Sect. C and A3, all the papers selected dealing 
with the thermal and frictional influences of the earth’s surface are grouped here for con- 
venience of the many meteorologists who are specially interested in them. Otherwise these 
would belong to sections B, C, D, G, or I. The distinctions between ‘turbulence’, ‘“‘“mountain 
meteorology’’, and “‘micro-aerology”’ cannot be made generally except from some particular point 
of view, which here is essentially a practical rather than a physical one. ‘Turbulence’? covers 
wind structure, eddy viscosity, Austausch, evaporation, ete., over level surface or small obstruc- 
tions, both in theory and in measurements to check theory or for aviation, ete. Many more 
references will be found in Lettau’s ‘‘Atmospharische Turbulenz’? and in works on Aerody- 
namics and Hydrodynamics (Sect. A3). ‘‘Mountain Meteorology’’ covers large-scale turbulence 
and special winds due to hills and mountains, as well as the departures of mountain observa- 
tions from free-air conditions and the adaptation of mountain observations in synoptic or 
dynamic meteorology. ““Micro-aerology”’ includes the actual observations of air structure 
(synoptic and average) in layers close to the ground to show surface influences, radiation, 
ete. Turbulence measurements are chiefly listed under that heading, however. ‘Micro-climat- 
ology’’ provides data on representativeness of surface weather reports and the mean circu- 
lation in the lowest layers; it is a valuable link in the application of synoptic meteoroogy to 
many practical ploblems. 
I. PRECIPITATION AND CONDENSATION; CONVECTION; CLOUDS; 
STRATUS AND FOG 
No attempt has been made to separate these topics as they intergrade and the number of 
citations is not inconveniently great. Only recent and summary papers on condensation and 
precipitation theory are cited (see also Sect. B., and A 4). “Convection” is here restricted 
to vertical convection from surface heating, and convergence, lifting, ete., resulting in 
instability and clouds, with applications to gliding, aviation, weather analysis and forecasting. 
The theory of lapse rates and of the kinetic energy of thermal stratifications is partly covered 
in Sections A, C, and E. Of the large literature on clouds some of the best aerological studies 
and synoptic applications have been selected; much further valuable material of this sort will 
be found incidentally in Sections B, D, E, G, and notably Siiring’s book gives further 
bibliography, especially on other aspects of clouds. 
J. INSTRUMENTAL PROBLEMS AND DEVICES 
Improvements in aerological instruments come so rapidly that only late work is of much 
practical value except to specialists in instruments. The instruction handbooks issued by the 
weather services of each country should be consulted for the national and official practices, 
which vary greatly. See also Sect. E 1, B, and C. 
Abbreviations 
The following condensed abbreviations are used. Other abbreviations are more complete 
and will probably be recognized at sight. 
Ann. d. Hydr. Annalen der Hydrographie und maritimen Meteorologie, Berlin. 
BAMS Bulletin of the American Meteorological Society, Milton, Mass. 
Beitr. Phys. fr. At. Beitrage zur Physik der freien Atmosphiare, Leipzig. 
Geog. Ann. Geografiska Annaler, Stockholm. 
Geofys. Publ. Geofysiske Publikasjoner, Norske Videnskaps Akademie, Oslo. 
Gerl. Beitr. Geophys. Gerlands Beitrage zur Geophysik, Leipzig. 
Met. Mag. Meteorological Magazine, London. 
MWR, or M. W. R. Monthly Weather Review, Washington. 
MZ, or M. Z. Meteorologische Zeitschrift, Braunschweig. 
QJRMS, or Q. J.R. M.S. Quarterly Journal of the Royal Meteorological Society, London. 
UGGI Union Géodésique et Géophysique Internationale. 
