1280 
high mountains, and (2) by flying them in aircraft. In 
either case, the scope presentations would have to be 
transmitted to weather forecasters; methods for accom- 
plishing this are discussed later. Considering the capa- 
bilities of present systems, the entire United States 
could be covered by about thirty carefully sited ground 
radars. 
With such extended coverage, a weather forecaster 
would have information concerning the distribution of 
precipitation in at least the major portions of cyclones. 
With this information he should be able to observe in- 
tensity changes and the speed of the entire system with 
considerable ease and precision. He should be able to 
keep a continuous watch on precipitation over a large 
area and perhaps forecast rainfall totals with accuracy 
at specified locations. From information gained from» 
previous observations, he should know approximate 
visibility conditions relative to the precipitation areas. 
He should be able to determine wind distribution in 
the lower levels of the troposphere from the movement 
of the precipitation cells, almost from minute to minute. 
By means of signal analysis he should be able to differ- 
entiate between rain and snow in many regions, and be 
able to determine zones, kinds, and amounts of icing. 
Radar should prove useful as a method of verifying 
forecasts; it should also be of assistance in the prepara- 
tion of long-range precipitation forecasts for specific 
points by providing more information on the effect of 
topography on precipitation patterns. In addition, from 
the standpoint of icing and turbulence, it should be of 
great help in the selection of best flight paths through 
unavoidable storm areas. 
Activities other than aviation should have a more than 
casual interest in the information which radar can yield. 
For example, electric power companies, by observing 
the progress of thunderstorms, should be able to anti- 
cipate power-demand peaks in various communities in 
the path of storms and adjust line loads accordingly. 
Also, accurate short-range forecasts for various sports 
and outdoor activities which may be affected by showers 
are already available in certain areas, and it may be ex- 
pected that demands for this service will increase in the 
future. 
Because of the ease of radarscope interpretation in 
location of the position of precipitation areas, television 
may be an excellent medium by which to convey the 
image of the PPI scope to the citizen for his own inter- 
pretation. Radarscope movies have already been shown 
several times on television programs in the Boston area. 
A possibly valuable application of radar storm detec- 
tion exists in the field of water conservation, flood con- 
trol, and irrigation [20, 54, 56]. If rainfall intensity can 
be even approximately correlated with the intensity of 
the PPI storm echo image, it should be possible to 
measure with useful accuracy the total rainfall caused 
by a storm in a given area within range of the radar. 
Critical catch basins could be studied by masking all 
other portions of the PPI scope and integrating the 
light emitted with a photoelectric cell. If developed, 
this technique might also be applied to measure the 
amount of snowfall in mountainous regions, thereby 
RADIOMETEOROLOGY 
eliminating the need for snow-survey teams in many 
areas. 
Equipment Development. The usefulness of radar for 
storm detection can be greatly amplified by improving 
equipment as well as observational techniques. Many 
instruments and accessories developed for special ap- 
plications have not yet been tested for their utility in 
radar storm detection work. It behooves the radar 
meteorologist to be alert for new developments in such 
fields as instrumentation, radar, television, communica- 
tions, and photography, as well as meteorology. Also, 
he should be ready to suggest improvements or modi- 
fications which will increase the utility of radar for 
meteorological purposes. For example, following are 
two suggested modifications which would probably facil- 
itate the observation of precipitation echo signals: 
Horizon-to-Horizon RHI Scope. This scope, used in 
conjunction with an antenna which scans from horizon 
to horizon through the zenith, would greatly improve 
the cross-section display presently available to the ob- 
server. This type of scan, as well as increasing the 
scanned volume by 100 per cent, would appreciably 
decrease the time needed for observations im all direc- 
tions. 
Gated Range-Height Indicator. This scope would re- 
move the necessity for vertical expansion of the RHI 
sweep by limiting the range presented on the scope to 
15 or 20 miles. The maximum indicated altitude could 
be adjustable from 15,000 to 50,000 ft. The scope could 
be controlled in range to present any 15- to 20-mile 
range increment from 0 to 100 miles. In this manner 
the true proportion of range to height would be pre- 
served while the same accuracy would be available for 
altitude measurements. There is no serious objection 
to limiting the range in this manner, for experience has 
shown that only rather limited portions of the RHI 
scope are of interest at any one instant. 
A certain type of radar receiver which was designed 
for nonmeteorological purposes might be invaluable 
for radar storm detection [49, pp. 553-554]. This re- 
ceiver, instead of giving linear amplification of the echo 
signal, amplifies logarithmically, the echo signals re- 
ceiving less and less amplification as they increase in 
power. By use of these “‘linlog” receivers, or others of 
similar characteristics, a far greater range of echo-signal 
power lies within the limits of scope presentation for one 
particular gain setting. This type of amplification might 
be useful in the presentation of storm echo signals 
which may have a vast range of power at any given 
time. Over a short distance or period of time storm 
echo signals may cover a range in excess of 60 decibels, 
from minimum detectable signal to signals which “sat- 
urate” the receiver. 
At present, one of the main restrictions on the use 
of radar for storm-detection information by weather 
forecasters is the lack of suitable means of disseminat- 
ing the scope information to all persons interested in it. 
There are several ways in which this could be accom- 
plished [49, pp. 726-735]. 
1. Verbal description, or code. 
2. Television of the PPI scope. 
