MODELS AND TECHNIQUES OF SYNOPTIC REPRESENTATION 
By JOHN C. BELLAMY 
Cook Research Laboratories, Chicago, Illinois 
Introduction 
An ideal station model can be said to be one in 
which the synoptic observations are rapidly and effi- 
ciently plotted in such a way that (1) the analyst or 
forecaster can ascertain, with a minimum of thought 
or effort, the complete three-dimensional distribution 
of atmospheric conditions, and the time changes of 
that distribution, and (2) all meteorological observa- 
tions made in a given region during a given time 
interval are readily available to the analyst or fore- 
caster. 
The latter condition is predicated on the fact that 
the basic station model is determined largely by the 
characteristics of the communicationsystem which must 
serve the varied interests and requirements of all users 
of the meteorological observations. It seems improbable 
that there will be developed in the near future suf- 
ficiently general and accurate thermodynamic models 
that the number of observations desired by all users 
will be reduced. 
Analysis of Present Techniques 
If we use the characteristics of this ideal station 
model for purposes of comparison, the following inade- 
quacies of present station models are apparent: 
1. The manual transcription of all data from teletype 
reports to the present station models at all receiving 
stations is obviously neither rapid nor efficient. This is 
especially obvious when such charts as thermodynamic 
diagrams, hodographs, cross sections, and nonstandard 
constant pressure charts are considered. Such charts 
are not now used extensively because of the excessive 
manpower required for their plotting and analysis. 
2. It is difficult for the analyst to ascertain the com- 
plete three-dimensional distribution of atmospheric con- 
ditions. Apparently, this is a result of the use of many 
different kinds of charts, or station models, on many 
pieces of paper. This difficulty is most serious when one 
parameter is considered alone. It is still present, how- 
ever, even when dynamic or thermodynamic models 
are used to correlate two or more individual parameters. 
Following is a discussion of the shortcomings of present 
techniques with respect to the three major dynamic or 
thermodynamic models now in common use. 
The Hydrostatic Equation. The hydrostatic equation 
can be considered as a dynamic model for correlating 
observations of pressure, temperature, and height. The 
common techniques now in use have the following short- 
comings with respect to this model: 
1. Only a small portion of the continuous pressure- 
height relationship in the vertical which can be obtained 
from radiosonde observations is used, since usually 
the heights of but a few standard-pressure surfaces are 
available to the analyst. The discarded data are very 
desirable for the accurate correlation of wind or cloud 
observations, which are made with respect to height, 
and radiosonde or aircraft observations, which are made 
with respect to pressure. These continuous data are 
also required for accurate aircraft altimetry. 
2. Present hydrostatic computations are sufficiently 
complex that usually they are carried out quantita- 
tively only at the radiosonde observation stations. 
This complexity limits the efficient correlation of repre- 
sentations of temperatures and heights to special cases 
and requires excessive experience and memory on the 
part of the analyst. 
3. Present sea-level pressure values cannot be cor- 
related directly with upper-air conditions since in 
general the particular values used for the reduction to 
sea level are unknown to the analyst. 
The Gradient-Wind Equation. The gradient (or geo- 
strophic) wind equation, in conjunction with the hydro- 
static equation, can be considered as being a dynamic 
model for correlating the wind, pressure, and tempera- 
ture fields. Present station models are not completely 
satisfactory for this dynamic model because of their 
inadequacies with respect to the hydrostatic equation. 
For example, at present the gradient-wind model can 
be applied easily only to a few standard constant- 
pressure surfaces and can be applied only indirectly 
to vertical representations. These limitations place seri- 
ous restrictions on possible operational use of pressure- 
pattern navigational techniques and precise aircraft 
altimetry, and seriously hinder the assimilation of the 
three-dimensional distribution of wind, pressure, and 
temperature conditions. 
Awr-Mass and Frontal Analysis. Present station mod- 
els have been designed largely for convenient air-mass 
and frontal analysis, and are quite adequate for that 
purpose. However, the efficiency of ascertaining the 
three-dimensional configuration and detailed charac- 
teristics of the air masses and fronts can probably be 
increased with improved station models. 
Only a small fraction of meteorological observations 
are made available in convenient form for the analysts. 
Of the upper-air wind observations only the winds at a 
few predetermined levels and perhaps a few hodographs 
are plotted. Of the radiosonde observations usually 
only the observations at a few predetermined pressures 
and a few complete thermodynamic diagrams are 
plotted. Of the surface observations usually only the 
values at 6-hr intervals are plotted. The teletype reports 
of hourly surface observations are sometimes available, 
but their form is hardly conducive to efficient assimila- 
tion by the analyst. The observations of pressure, 
temperature, humidity, wind, ceiling, etc., which are 
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