Exploring the Unknown - NASA's History Office

[Altostratus] Very often these formations contain considerable vertical development.
[Nimbostratus] This seems to be especially true when these forms are associated with
the passage of a front.
It is clear that any attempt to formulate an atlas of cloud appearance as seen from
high altitude is a major undertaking. The work done on the subject in this report represents,
at best, the beginning of the work that must be accomplished to make high-altitude
cloud photographs a usable weather tool.
THE ANALYSIS
Having once established the identity of almost all the clouds viewed, the formation of the
synoptic weather picture becomes the next problem. The following question arises: Given an
over-all cloud picture, what, in fact, can be determined, either directly or indirectly?
According to conventional meteorological practice, the various parameters, such as
pressure, temperatures, etc., are plotted on a map, and the subsequent analysis of these
quantities produce the synoptic picture. Almost the reverse is true in the case at hand.
Here the synoptic situation must first be established, and the various parameters must be
estimated from it. Actually, it is not quite so straightforward a procedure. Rather, it
becomes a “hunting” technique, in which one makes a first approximation to the over-all
weather situation, using the clouds, and, from this, a first estimate of the value of temperature,
pressure, humidity, etc. This picture of the weather is then modified to fit [16]
obvious deviations of the estimated values from those indirectly observed. This process
continues until a satisfactory situation is evolved that appears to fit all existing conditions
(an attempt being made to satisfy both physical and theoretical considerations); from this,
final estimations of the various parameters are made. (Several possible approaches to the
problem of approximating the synoptic picture are discussed in the section entitled
“Suggested Methods of Attack on the Problem of Determining the Synoptic Situation.”. . .)
The normal observable meteorological parameters may be divided into two main categories,
viz., those that may be estimated in some measure directly from observations of
the clouds and/or ground, and those that require a knowledge of the over-all weather patterns
before an estimate can be made. In the first category may be listed wind, humidity,
precipitation, and a variable not normally considered by itself as such—degree of stability.
In the second listing may be found pressure (and pressure tendency) and temperature.
Before an attempt at its analysis can be made, a considerable amount of experience and
general knowledge of the workings of the atmosphere is required concerning each item,
regardless of which category it comes under. It is found that this estimation method is neither
a quick nor a simple process, regardless of the qualifications of the analyst. Rather,
each of the items requires a very careful study and the weighing of all the possible influencing
conditions before approximate values can be assigned.
As a result of this pilot study, several suggested methods of estimating the various
meteorological parameters were evolved and are discussed as follows:
Wind
EXPLORING THE UNKNOWN 197
1. From the established meteorological models it is assumed that certain definite
weather situations will produce certain sequences of clouds preceding or following them.
This will therefore tend to orient the situation with respect to the ground. Once this orientation
has been established, the wind direction may be approximated through a knowledge
of the theoretical circulation associated with a given synoptic weather situation.
2. It has been noticed in several photographs that, in the presence of strong upper