MODELS AND TECHNIQUES OF SYNOPTIC REPRESENTATION 
The use of D eliminates most of the variation of 
pressure with height and very accurate pressure- 
height curves (D plotted as functions of zp) require 
relatively small space. These curves permit rapid, easy, 
and accurate correlations between observations meas- 
ured and plotted with respect to pressure zp, and ob- 
servations measured and plotted with respect to height z. 
It is convenient to choose the standard atmosphere 
with which to define z, to be that which is also used for 
the calibration of aircraft altimeters. The quantity D 
then becomes merely the additive conversion factor to 
be applied to pressure values 2p, as measured with alti- 
meters, to obtain heights z. This choice of definition of 
the standard atmosphere provides an integration of 
meteorological and flight techniques which should be 
advantageous for all concerned. 
In terms of the parameters D and zp, the hydrostatic 
equation [1] is linearized to the form: 
(2) 
where S* is the virtual specific temperature anomaly 
defined by 
T* — T, 
aa @) 
Here 7* is the virtual temperature at any given pres- 
sure, and 7’, is the temperature at that pressure in the 
standard atmosphere. 
If temperatures are represented by the parameter 
S, they are readily expressed as change of height D 
per unit change of pressure z,. Accurate correlations 
between any temperature conditions and the corre- 
sponding pressure-height relationship are then immedi- 
ately obvious. This change from the usual exponential 
form of the hydrostatic equation to a linear form ap- 
pears to be even more advantageous than the compa- 
rable use of decibels in sound, light, or electrical meas- 
urements. 
It appears that the use of D, rather than ‘“sea-level”’ 
pressures, for expressing the values of surface pressure 
observations [1, 2] has several advantages. Chief among 
these are more accurate representations of horizontal 
pressure gradients near the surface of the earth and 
convenient exact correlations with upper-air pressure- 
height relationships. 
The Gradient-Wind Equation. The use of parameters 
such as 2p, D, and S permits the continuous representa- 
tion in the vertical of the wind, pressure, and tempera- 
ture fields as related in the gradient-wind model. This 
possibility facilitates the assimilation of the three-di- 
mensional atmospheric conditions. It also permits the 
convenient analysis of the contours of any desired 
constant-pressure surface so that the extensive use of 
pressure-pattern navigational techniques becomes fea- 
sible. Such representations would also be very useful 
for precise aircraft altimetry. 
The present barbed-arrow type of representation of 
the winds does not seem to be suitable for exhibiting 
the continuous variations of wind with respect to time 
713 
or height. Another more satisfactory method of repre- 
senting such wind observations [2, 3] consists of drawing 
graphs of the east-west and north-south components 
of the wind as functions of height or time. 
Air-Mass and Frontal Analysis. The techniques of 
isometric graphical representations can probably be 
applied with advantage to air-mass and frontal analysis. 
This is especially true of maps which contain all the 
temperature and humidity observations [3]. Such maps, 
together with similar maps of pressure, wind, and cloud 
conditions, should provide convenient means of in- 
creasing the ease and accuracy of both detailed and 
general analysis of air-mass and frontal distributions 
and characteristics. At present the major inadequacy of 
the isometric maps for this purpose appears to be the 
difficulty of plotting the cloud and state-of-weather 
observations from present teletype reports. 
It is apparent that the efficient transmission of all 
observations can most conveniently be accomplished 
in terms of the continuous variations of the various 
parameters. For example, upper-air winds should be 
transmitted as continuous functions of height; radio- 
sonde temperature and humidity observations and cal- 
culated heights should be transmitted as contmuous 
functions of pressure; and surface observations should 
be transmitted as continuous functions of time. Of 
present observations, those of clouds and the state of 
the weather offer the most difficulty for this type of 
transmission, primarily because of the tremendous 
amount of such information available. Some techniques 
have been proposed [3] for the continuous representation 
of clouds, etc., which, though not yet completely satis- 
factory, do indicate that very useful results can be 
expected from this method of approach. 
The use of a direct-writer communication system 
seems to be necessary for the transmission of all the 
observations since automatic segregation of particular 
observations from the great mass of data would un- 
doubtedly be required. This segregated plotting would 
be feasible with direct-writer systems either in terms 
of graphs, proportional lines, or digital numbers, as 
desired by each individual analyst. 
Conclusion 
The inadequacy of present techniques of represent- 
ing synoptic observations can be traced to three sources: 
the use of inadequate parameters with which to de- 
scribe the observations, the use of inadequate methods 
of plotting these parameters on maps or charts, and 
the use of inadequate communication systems. It ap- 
pears that most of these shortcomings can be eliminated 
with the following techniques: the use of parameters 
defined in terms of deviations from standard atmos- 
pheric conditions, the use of isometric graphical repre- 
sentations of the observations, and the use of a direct- 
writer type of communication system. 
These new techniques are independent of each other, 
and could be adopted individually as opportunity or 
desire permits. For example, all radiosonde observa- 
tions could be reported and plotted with present tech- 
niques in terms of zy, D, and S. In fact, the parameters 
