Snow—continued 
erystals—continued 
irregular assemblage of columns and 
plates, 212 
irregular snow particles, 213 
malformed, 212 
method for 
graphs, 209 
natural and artificial, comparison 
between, 217 
needle erystals, 212 
practical classification, 213 
principles of classification, 209 
rimed crystal, 213 
replica techniques for studying, 221 
scientific classification, 212 
spatial assemblage of radiating type, 
2 
taking photomicro- 
natural and artificial, 219 
spatial hexagonal type, 212 
stellar crystal with plates at end of 
branches, natural and artificial, 
217 
studies, application to meteorology, 
217 
with irregular number of branches, 
212 
with twelve branches, 212 
electrical characteristics, 129 
electrical properties, 227 
factor in hydrology, 1050 
formation, effect of fragmentation 
nuclei on, 226 
effect of freezing nuclei on, 224 
effect of spontaneous nuclei on, 225 
effect of sublimation nuclei on, 224 
factors controlling, 223 
physics, 177 
melt, estimate, 1044 
forecasting, 1053 
relationship to experimental meteor- 
ology, 221 
Snowflake size, aircraft measurement, 
1229 
Sodium, atmospheric, 272 
chloride condensation nuclei, growth 
curves, 168 
Soil bacteria, exchange between earth 
and atmosphere, 1106 
Solar activity, variable, nature of, 379 
periodic character, 379 
Solar constant, 13, 17, 380 
determination, 50, 52 
methods of measurement, 17 
numerical value, 18 
value, 380 
variation, 18, 380 
Solar control, of upper atmosphere, 247 
Solar effect, on ozone layer, 293 
Solar energy, at earth’s surface, 28 
average conditions, 29 
through cloudless sky, 28 
through clouds, 28 
extraterrestrial, on horizontal surface, 
1 
in ultraviolet, 295 
variations, research needed, 388 
weather changes and, 379 
Solar prominences, 379 
Solar radiant energy, modification by 
earth, 13 
modification by earth’s atmosphere, 13 
Solar radiation, see also Sun, radiation 
Borption, spectral by water vapor, 
total water-vapor, 21 
absorption by clouds, 21, 31 
absorption by earth’s atmosphere, 19 
absorption by earth’s surface, 22 
absorption by ionosphere, 19 
absorption by ozonosphere, 19 
at ground, 30 
effect on glaciation, 1010 
effect on Grosswetter, 820 
INDEX 
Solar radiation—continuwed 
factor in climatie change, 1010 
outside the earth’s atmosphere, 13 
scattering, 22 
by dust, 23 
by liquid water droplets, 24 
multiple, 25 
spectral, by water vapor, 23 
spectral molecular, 22 
total molecular, 22 
total water vapor, 23 
terrestrial effects on, 19 
upper-atmospheric heating, 31 
Solar rays, illumination of upper atmos- 
phere by, 248 
Solar-topographic theory of 
changes, 1016 
Solar ultraviolet radiation, effect on 
upper atmospheric gases, 248 
Solenoidal index, 564 
Sound pressure, waves, 374 
Sound propagation, in the atmosphere, 
366 
research needed, 375 
through upper atmosphere, 304 
Sound rays, in moving air, 367 
in quiet air, 366 
Sound velocity, 366 
and temperature, 374 
Sound wave energy, absorption, 368 
effect of distance between rays, 368 
in atmosphere, 368 
Sound waves, abnormal audibility zones, 
371 
climatic 
in gases, theory, 366 
in moving air, 367 
in quiet air, 366 
natural, observation, 371 
observation, interpretation, 371 
recording, instruments for, 370 
temperatures derived from, 305 
through stratosphere, 371 
through troposphere, 371 
use in studying upper atmosphere, 
251 
Sounding balloon, use in studying upper 
atmosphere, 251 
Space charge, measurement, 149 
Space medicine, 1121 
Spectra, atomic, different ranges of wave 
length, 265 
atomic particles, 265 
infrared, of carbon dioxide, 296 
of water vapor, 296 
molecular particles, 265 
Spectral line, radiation from, absorption 
law, 35 
Spectrograph, radar signal, 1278 
Spectrophotometer, Dobson, 276 
Spectrum, aurorae, 350 
hydrogen lines, 351 
intensity effects, 350 
nitrogen bands, temperature de- 
termination from, 351 
sodium lines, 351 
wave lengths, 350 
night-sky, 341 
Spicules, 379 
Spillover, rainfall, orographic, 1039 
Spontaneous nuclei, effect on snow for- 
mation, 225 
Spores, exchange between earth and at- 
mosphere, 1107 
Squall lines, 689; see also Instability lines 
prefrontal, 716 
and pressure jump lines, 427 
Stability properties of large-scale at- 
mospheric d sturbances, 454 
Standard operative temperature, 1115 
Static, precipitation, 134 
Steady-state flow, under 
equations for, 430 
Stooping, 66 
inversion, 
1331 
Storms, Antarctic, 924 
effect on electrical conductivity of air, 
110 
electrical state in, 129 
observation, radar, 1265 
radar appearance during, 1271 
surge method, of predicting swells, 
1098 
tropical, frontal analyses, 866 
see Tropical cyclones 
Stratocumulus, liquid-water concentra- 
tion, 1199 
Stratosphere, composition of air in, 8 
lower, frost point determination in, 313 
normal circulation, 553 
ozone in, 284 
radiation in, 46 
radiational heating of, 47 
sound waves through, 371 
Stratus, effect of cloud seeding on, 236 
solid precipitation in, 223 
forecasting time of dissipation, 1187 
liquid-water concentration, 1199 
Strays see Sferics 
Streak lightning, 141 
Stroke, return, 136 
Sturbs see Sferics 
Sublimation, formation of ice crystals 
by, 207 
nuclei, 174, 192 
effect on snow formation, 224 
on cloud elements, 204 
Sulfur dioxide, effect on condensation 
nuclei formation, 186 
Sulfur dioxide apparatus, for measuring 
atmospheric pollution, 1140 
Sulfur dioxide content of atmosphere, 7 
Sulfuric acid, atmospheric, determining, 
Sun, chromosphere, 13 
corona, 13 
enlargement when near horizon, 62 
ionized layers, heights and pressures, 
15 
photosphere, 13 
radiation, see also Solar radiation 
infrared, 14 
fluctuation in far ultraviolet, 15 
fluctuations in infrared, 17 
fluctuations in near ultraviolet, 16 
fluctuations in radio waves, 17 
fluctuations in visible, 17 
fluctuations of emitted, 15 
near infrared, 13 
short-wave radio, 14 
ultraviolet, 14 
unmeasured, 15 
visible, 13 
Sun, reversing layer, 13 
ultraviolet intensity, 1119 
Sunlight, average spectral distribution, 
13 
Sunrise, in upper atmosphere, 248 
Sunset, upper atmosphere, 248 
Sunshine recorders, 55 
Sunspot cycles, effect on Grosswetter, 
819 
Sunspot number, relative, 380 
and meridional and zonal flow types, 
840 
Sunspots, 379 
follower, 380 
leader, 380 
Superrefraction, areas subject to, 1290 
description of, 1290 
explanation of, 1291 
propagation, 1294 
radio duct, 1292 
Surf, forecasting, 1083 
Surface friction, heat transportation, 465 
Surface map, geometrical extrapolation, 
769 
physical extrapolation, 770 
prognosis, 769 
