THE MN-MACHINE RELATION IN
METEOROLOGICAL DATA
PROCESSING
by
ROBERT CHARLES GAI4MILL
B.S., University of Rochester
(1959)
SUBMITTED IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE
DEGREE OF MASTER OF
SCIENCE
at the
MASSACHUSETTS INSTITUTE OF
TECHNOLOGY
June, 1963
Signature of Author
Certified by
Accepted by
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,.................
Department of Meteorology, May 17, 1963
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Thesis Supervisor
. *
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Chairman, Departmental Committee
on Graduate Students
ABSTRACT
THE MAN-MACHINE RIATION IN
METEOROLOGICAL DATA
PROCESSING
by
Robert Charles Gammill
Submitted to the Department of Meteorology
on May 17, 1963, in partial fulfillment of
the requirement for the degree of
Master of Science
At present operational weather forecasting on a com-puter is an incompletely programmable problem. This situ-ation has every prospect of continuing to be so. Such
problems require the application of intelligence in the
attempt at solution of their unprogrammable aspects. We
have two alternatives in providing this: use of
1) human intelligence
2) artificial (machine) intelligence
Artificial intelligence is not yet adequate for our task,
and may not be for many years. Thus, we must find means for
direct application of human intelligence in our problem solution. Man-machine symbiosis is the method by whtoh we can
achieve this. Symbiosis is the complementary utilization of
the talents of man and machine in a system which is more
capable than both workinG separately. That is, each works
on those portions of the problem at which he is most capable.
A possible future weather central, using such a philosophy,
is described. Feasibility of on-line human manipulation of
isopleth patterns is demonstrated.
Thesis Supervisor: frederiok 'Sanders
Title: Associate Professor of Meteorology
3
TABLE OF CONTENTS
1. Operational Weather Forecasting
1.1 Data Collection
1.2 Data Processing
1.3 Useage
2. The Weather Central Today
2.1 Equipment
2.2 Programming
3. Man Computer Symbiosis
3.1 Problem Areas for Man-*Computer Symbiosis
4. Feasibility of Meteorological Symbiosis
4.1 The Computer
4.2 The Program
4.3 Results
5. The Weather Central of the Future
5.1 Equipment
5.2 Programming
FIGURES
Number
Page
14
2
3
4
9
10
19
5
36
6
7
8
9
10
11
12
13
38
38
39
39
40
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1. OPERATI ONAL WEATHER FOR
It OPERATIONAL WEATHER FORECASTING
This thesis will consider the problem of the most
effective design for a weather central Using automatic data
processing techniques.
A weather central is an integral
part of the data collection, processing and distribution
system which provides operational weather forecasting ser.
vice to users here and abroad.
processing phase.
Its primary job is the
In order to reach concrete conclusions
about the design of a central, we must examine the job to
be done, and the materials to be used.
Operational weather forecasting has been going on for
many years.
It started long before anyone had a clear idea
of the physical mechanisms of the atmosphere.
Today, with
more knowledge about the mechanisms, we are in a better
position, but the processes through which forecasting services are provided are essentially the same.
A simplified
flow diagram of what occurs is shown below:
a) DATA COLLECTION
b) PROCESSING
F1
c) USE
-
-
data sample
processing
-picture of
the spacem
-
time
character
f igure 1
I-...
.....
..-
-
_
5
a) Data gathering must be treated as a sampling problem,
for the size of the population (the molecules of the
atmosphere) makes complete measurement of its characteristics unfeasible.
b) The processing system (meteorologist or computer)
converts the data sample into a space-time characterization of regions of the atmosphere*
a) This characterization is given to the user, who
uses the information in making decisions.
The purpose of the system is to provide the user with knowledge of the future (and occasionally past or present)
location or distribution of meteorological phenomena which
affect him.
The primary concern of this paper will be the design
of a processing system.
As will be seen later, processing
is the only phase over which it is possible to exert much
control.
The great majority of data collection agencies are
uncontrollable due to interagency and international boundaries.
Thus, the safest approach is to design a processing
system which can adapt to existing conditions of data input,
and hope for the best in the improvement of data collection
methods.
Since we will be assuming that the present cond-
itions of data collection are unalterable, it is important
to consider what those conditions area
1.1 DATA COLLECTION
There are two major types of meteorological observations.
These are: 1) radiosonde 2) surface.
The radiosonde observation is made from a helium filled
balloon, transmitting information about temperature, pressure,
and relative humidity at certain levels as the balloon rises.
Wind speed and direction at desired levels can also be found
by tracking the balloon using radar or theodolite.
These
observations are taken at least every 12 hours (at 0000 and
1200 Greenwich Mean Time) by approximately 500 Northern Hemisphere stations.
Because of the number of instruments which
are thrown away under this system, they are inexpensive and
somewhat error prone (the radiosonde is not one of the weakest links in the data collection system).
Furthermore, the
data which reaches the Ground must undergo considerable
computation before it .s prepared for transmission.
Thus,
there are at least two ways that a radiosonde observation
may be in error before it leaves the observing station.
In
addition, the most important observations are those taken
under difficult conditions, such as during a thunderstorm,
from shipboard, or from an isolated station.
Also, different
countries use different instruments, different units, and
different procedures, with the result that the data will be
subject to error of many types.
The standardization and
improvement of this data collection method is a slow and
continuing process.
part in such change.
Political considerations play a large
Surface observations are subject to a different type
of problem than the radiosonde.
Since the instruments are
not discarded after each use, and since there is little
computation to be done, surface observations tend to be
more accurate.
However, because of the ease with which
they may be taken, and the need for heavy coverage, many are
taken by people with little meteorological experience and
sometimes little interest.
Especially in ship observations,
errors are found due to incorrect use of the instruments,
difficulties of shipboard measurement, and carelessness.
Since these ship observations are supplied on a voluntary
basis,.little can be done to improve their quality.
Because
they are taken in regions of sparse coverage, they take on
great importance.
Many other types of observations are made, the most
important being pilot reports from aircraft.
Here, instru-
ment inaccuracies, errors of observation location, carelessness, political problems, and other factors, limit our ability to improve observation accuracy.
These observations also
tend to be more important because they often come from areas
of sparse coverage.
Grave difficulties stand in the way of hopes for substantial improvement or standardization of global observational data.
Even the difficulty of achieving further standard-
ization and accuracy within the United States should not be
blithely discarded, for politics like crabgrass is ubiquitous.
8
Moving to the next phase of data collection, once the
observation and associated calculations have been completed,
the data are ready to be encoded into a report.
The codes
which are used are catalogued in handbooks distributed by
the World M-eteorological Organization.
Variations in the
coding format occur due to observation type, time, national
practice, agency (Air Force, Navy, FAA, Weather Bureau to
cite a few), and sometimes individual preference.
Some of
these variations are catalogued in the handbooks, many are
not.
Major changes in format sometimes occur with little
notice.
After the report has been encoded it is transmitted by
teletype, radioteletype or radio.
Before the report reaches
our processinS center it may have been retransmitted up to
ten times, come halfway around the world, been edited one or
more times, had its units converted, been decoded and recoded
in another format (summaries eto4, and run throuGh several
storage devices, such as paper tape punches or magnetio tape
recorders.
Almost all the processes described involve
human activity.
At every one of the points described, human,
electronio, or mechanical error may be introduced.
A further problem inherent in the data-gathering phase
is the timing problem, or coverage,
Because of the meander-*
ing path which a report may take in reaching us, the amount
of human intervention necessary, and the numerous poesibilities for communications problems (electronic disturbances
9
or equipment failure), many reports will not be available in
time to be included in our data sample, or will be so garbled
that they will be unusable.
This problem Is not serious in
this country, but in the South Pacific, where regions the
size of the United States have no data, one observation can
mean the difference between a reasonable forecast and
nonsense.
Further, the regions of sparse data are those in
which communication ability is least assured.
Reports from
sparse data areas are often difficult to obtain, and to
interpret once received.
Yet, they are extremely important
since the atmospheric mass which they must be used to characterize is so enormous.
In summary, the data acquisition problem may be flow
diagrammed as below:
figure 2
instrument .
and human
errors
ATMOSPHERE
instrument
q
human
inst
ent
linstrument
human
I
1human 1.
transmitter
transmitter
Iraceiver.
.receaver
Itransmitter
...
..
transmission
line losses
instrument
and human
errors
transmission
line losses
instrument
errors
ZeceiverI.
human
transmitter
tran mitt
trsmit
receiver
receiver
r
PROCESSING STATION
i
*
10
It must be reiterated that the imperfection of the data
collection network is a much stronger function of politics
than of technology.
However, even if the political problems
were to be miraculously dispersed, those observation points
most desperately in need of sophisticated measurement and
transmission technology are those least able to afford and
maintain the necessary equipment.
1.2 DATA PROCESSING
The data processing phase be3ins with the reoeipt of
the data.
Immediately we are faced with the problem of
determining how long after observation time (JMT at which the
observations were taken) one must wait before the data sample
can be considered complete.
We want to find that point in
time where a further wait will not increase the accuracy of
the output sufficiently to overcome its decreased usefulness
due to lateness&
data time
~-
sum of both
completeness
of samplle
timeliness
figure 3
time
Once a decision has been made, our limitations in time become
well defined.
Next in order is the data identification,
decoding, consistency checking, and interpretation.
The
different parts of the processing phase are strongly interrelated, but will be separated for clarity.
Identification of reports takes two forms
1) station identification
2) classification of report type
Stations are identified by a five digit number, the first
two digits representing the block number (a geographic and
politioal grouping of stations) and the final three digits
the station number within that block.
Reports not meant
for international distribution (e.g. from stations in North
America) usually do not include a block number, so that
ambiguities sometimes arise.
The identification process
involves the supplying of a location for the report, either
from memory, by use of a map of station locations, or use of
a library of station numbers and locations (in computer
methods).
Extreme difficulty is encountered when the station
identification is incorrectly received or when no location
is known for the particular identification.
In these cases
fairly sophisticated detective work is necessary.
Classification of report type is not always easily
accomplished.
Report lengths vary from five to 100 words
(each word approximately five characters).
There are ten to
twenty major types of report, each having many variations
within its own format.
Some reports use alphabetic and
special symbols, others use only numbers.
In some reports
all the words have exactly five characters; in others
various word lengths occur.
Some of the information trans-
mitted over meteoroloGical teletype lines is written in
plain language, except that it is abbreviated, and the set
of abbreviations to be used is the prerogative of the sender.
Some report types strongly resemble another, but incorrect
classification will give meaningless information.
Within
a bulletin (group of reports identified by a heading) there
may be several types of reports.
Thuso it is not possible
to set down a simple set of rules for report classification.
Two types of consistency may be checked for:
1) format (coding structure)
2) physical (satisfaction of physical constraints
on a fluid)
Format checking is the use of redundancy of report structure
to discover and, when possible, correct garbling.
This is
normally done during the decoding of the report, le., the
conversion of the coded information to meaningful meteorolog-ical parameters.
may beGin.
Once this is accomplished, interpretation
During interpretation our knowledge of the
physical constraints on the atmospheric fluid is used to
indicate parameters which are doubtful.
Interpretation takes
two forms:
1) analysis (two dimensional mapping on constant
pressure surfaces)
2) vertical analysis on aerological chart (one
dimensional mapping of individual
radiosonde report)
Analysis is the plotting on a map of all the data which is
13
available at a pressure level and the addition of isopleths
(lines of constant value of the quantity) to indicate the
distribution of the parameter of interest.
In computer
methods the values at a predetermined grid mesh are obtained
by interpolation from the observations.
Both contouring and
grid mesh production are essentially a two dimensional integration of discrete measurements of a surface, since the
family of isopleths may be regarded as depicting the topo-W
graphy of a surface.
Our filtering process is one of looking
for unrealistic space variations of the present surface and
of the time change of the surface since the last data time.
Analysis can be of great use in detecting incorrect data, for
much is known about constraints on horizontal patterns, both
spatially and in time, and about the meanings of significant
features of such patterns*
A problem concerning our know.'
ledge of atmospheric constraints is its conditional character.
For example, wind speeds of 150 mph are rare, except in the,
vicinity of the jet stream, or of a hurricane.
Thus, normal
constraints on the atmosphere break down just when we are most
interested in accuracy.
We are most likely to disbelieve a
report which indicates a strong disturbance, and believe one
that shows nothing of great interest.
Vertical analysis is the plotting of reported data
from a radiosonde Ieport on an aerological chart.
Much can
be learned from the vertical distribution of temperature,.
14
dew point, and wind velocity.
Constraints are also well
defined in the vertical, especially with relation to lapse
rates (the rate of deorease of temperature with pressure).
There is a limiting lapse rate that is likely to occur over
any but extremely shallow atmospheric layers.
Here again,
we will have a tendency to disbelieve indications of unlikely
occurrences.
If true, these are of considerable interest.
Once a three-dimensional, present-time picture of the
atmosphere has been produced through the two means described,
the process of forecasting begins.
This process takes many
forms, depending upon the type of forecast desired and the
time range for which it must apply.
Forecasting is the
extrapolation of our three-dimensional picture of the atmosphere to a future time through an Integration process.
The
forecasting process is highly complex, and much effort has
been devoted to development of forecasting models in recent
years.
Forecasting schemes which are presently used are of,
two types: experience, ie. statistical, and dynamical.
Statistical forecasting is a recent development associated
with the systemization of experience forecasting,
Experience forecasting is based on concepts such as:
1) Persistence
Statistically the most likely future occure
rence, for short time periods, is no change.
2) EXtra olation
Weather systems tend to move at a velocity
proportional to the wind velocity at 500
millibars (about 18,000 feet).
15
Statistical forecasting makes use of the past records of the
time behavior of weather systems to predict the behavior of
similar present systems.
Statistics also provide us with a
means for predicting the most likely weather for a time
period, known as olimatology.
Dynamical forecasting is one of the more recently
developed areas of meteorology.
The advent of large digital
computers has made possible the approximate solution of the
non-linear equations of fluid dynamics, specialized for the
large-scale motions of the atmosphere, in an amount of time
which makes forecasting by this method feasible.
It should
be noted that these techniques have found direct utility
only in wind forecasting, nevertheless, dynamical forecastinG has had a Great impact on meteorology*
At present there
are at least two weather centrals in the United States making
suoh forecasts.
All is not sweetness and light in the field
of dynamical forecasting, however.
Due to causes such as
the addition of scale assumptions (to prevent energy from
appearing in very short iwave lengths and masking meteorologically interesting wave lengths), the equations represent
the atmosphere incompletely.
Thus, although dynamical pre.
diction schemes can exceed purely human capabilities on the
average, there are many situations (statistically infrequent
but often important) in which a man is able to recognize that
the dynamical saheme is in error.
1*3 USEAGE
The users of processed products are usually not intere*
ested in large geographio areas.
They are interested in a
localized reGion or, in the case of aircraft, a route.
The
individual user Is interested in a variety of parameters
that is large, and not necessarily known.
Thus, in most
cases it is not possible to tailor output to the users9
needs; instead, products desoribing the overall atmospheric
character are sent to him to be interpreted in terms of
their impact on his area of interest.
This interpretation
usually involves examination of the present situation, and
of the products received.
If the products do not show
significant activity, the forecast will usually be for
persistence of present conditions plus any statistically
known variations due to local characteristics.
Tailoring of output to user needs is done occasionally,
but is difficult because requirements often change.
An
example of such tailoring occurs in the Global Weather
Central at SAC headquarters where route wind forecasts are
made for particular aircraft routes.
Considerable difficulty
can occur when routes are changed rapidly, or when require4
ments for special accuracy arise.
17
2. THE WEATHER CENTRAL TODAY
The weather centrals described in the following section
are the National Meteorologioal Center at Suitland, Maryland
and the Global Weather Central at Strategic Air Command
Headquarters, Omaha, Nebraska.
Centralized processing of weather data existed before
the development of automatic data processing systems, but
the volumes of data involved in large scale weather prediction
make the use of a computer an obvious step.
The- development
of dynamical prediction models and sophisticated statistical
methods has made the use of computers mandatory, for the
associated computation is prodigious.
2.1 EQUIPMENT
Both centrals use the IBM 7090 as the main processor
(with a probability of conversion to 7094 in the future).
They both have numerous magnetic tape units, an on-line
printer, and an on-line card reader.
Both have recently added
an IBM 1301 disk file, for large--volume rapid-access memory.
At both centrals off-line output is handled in two ways:
1) IBM 1401 with magnetic tape units, paper tape
punch, and high-speed line printer.
2) Electronics Associates Data-Plotter with magnetic
tape unit.
The output devices listed are used for display of final
output 'in the form of contour maps or messages for teletype
transmission.
Both of these methods produce hard copy which
is then displayed for reference, transmitted over facsimile
or teletype circuits, or filed.
Display of intermediate
results for monitoring purposes must be on the on-line
printer, which is very slow, so monitoring must be kept to
a minimum.
In their approaoh to input, the two centrals differ
slightly.
NMC uses special purpose gear designed by AVCO,
which puts the teletype messages on maGnetic tape to be
processed by the 7090.
GWC has been using its 1401 in the
conversion of teletype paper tape to magnetic tape.
Under
development is a processins system in which the ADX computer
of International Telephone and Telegraph is used for realtime processing of teletype data direct from transmission
lines.
This computer will do some processing of the input
data and place it on the disk storage to be used by the 7090.
It is probable that direct output to teletype lines will be
handled by this computer in the future.
2.2 PROGRAMMING
Programming for automatic weather data processing
systems has grown as an adjunct to dynamical prediction.
Initial applications of computers to meteorolo3y were only
in that area.
As attempts to make dynamical prediction
operational have borne fruit, it has become necessary to
produce programs quickly to automate the input and output
phases of processing,
In trying to produce such programs
it has been found, particularly with respect to input, that
there are some rather difficult problems.
In general, the
following, flow diagram describes the programs necessary for
numerical weather predictions
FLOW DIAGRAM 0F' AUTOMATIC WEATHER DATA PROCESSING SYSTEM
INPUT DEVI CE
CHECKING
OUTPUT
identification
station in
library?
report type and
location
decode
format
consistency
standard format
report
hydrootatic
(vertical)
analysis
vertical
physical
consistency
vertically
consistent
report
analysis
horizontal and
time consistency
srid maps for
present time at
levels: sfc.,
1000 mb., 850 mb.,
700 mb., ..
forecast
grid maps for
future times at
levelas sfc.,
1000 mb., 850 mb.,
700 mb., ...
verification
statistical ability
of forecast method
output programs_
contour maps and
teletype messages
DISPLAY OR TRANSMISSION DEVICE
figure 4
20
Programming is of the nowntop variety due to the hish cost
of computer time and larGe volumes of data to be processed.
Programs in sequence are treated as entities, each taking
its input from magnetic tape and putting its output on
another tape.
Each of the proj;rams has no communication
with the other programs except through input and output.
From the fore3oion
discussion there is considerable
doubt whether a system of the type presently used can ever
do a completely satisfactory job of operational weather data
processing.
Some decisions must be made in a rather arbi-
trary manner, and most algorithms incompletely represent
the methods used by a human being.
The result is that
difficulties arise in the following areas:
1) station identification and location
2) classification of report type
3) deearbling through format consistency
4) standardization of units and correction of
systematic errors
5) ooverage sufficiency or requests for missing data
6) reasonableness of vertical patterns
7) reasonableness of horizontal and time patterns
8) reasonableness of forecast patterns
9) adaptability for special output
Because of the numerous problem areas, and the lack of human
control, products of automated data processing facilities
are sometimes unsatisfactory and almost always less accurate
than they miGht be with human assistance.
For this reason
automatic weather data processinG centers have served pria
marily in a supplementary capacity.
They have not sup-
planted the large number of human beings in the weather
central.
Some of the former manipulative labor has been
takoen over, but, for the most part, humans are doing the
same jobs they have always done.
Why has the computer been unable to replace the human?
There are two reasons:
1) the need for reliability
2) the necessity for adaptive or intelligent behavior
The need for ieliability is most easily illustrated by the
situation at the Global Weather Central.
The strategic
offensive capability of the United States is partially
dependent upon the availability of high quality products
from that facility.
Thus, to Guarantee reliability in spite
of equipment malfunction or program failure, it is necessary
to supply sufficient personnel to perform, by hand, operations
similar to those performed by the computer.
Such a means of
providing back-up capability is extremely costly.
Equipment reliability is achievable through means
which have become well developed in the space and commandcontrol industries.
In particular, the use of redundant
components can lead to extremely high reliability.
An
example of the use of redundancy in a successful computer
system is SAGE of the Air Defense Command.
Such a system
gives extremely high assurance of continuous operation, alone
22
with the high precision we have come to expect from the use
of computers.
Program reliability is somewhat more difficult to
achieve.
Here one finds the problem of large numbere of
eventualities and the necessity for maintaining high quality
in spite of unforseen circumstances.
Such a problem requires
the ability to adapt, or apply intelligence.
us to the second area of concern.
This brings
The study of artificial
(machine) intelligence is progressing, by leaps and bounds,
but is still not equipped to handle problems of the real
world.
Progress is being made in the solution of problems
which have well defined rules, 1e
Games esuch as chess and
checkers, and mathematical theorem proving.
However, the
level of intelligence being exhibited by machines is still
too low to be of use in weather data processinG.
Our answer
lies not in programming intelligence into the computer, but
in man-wcomputer cooperation (or symbiosis, as it has been
termed by Licklider, 1960).
23
3, MAN-wCOMPUTER SYMBIOSIS
Man-computer symbiosis is a subclass of man-mmaohine
systems.
Certain types of man-machine systems have been in
existence for many years.
Examples of such mechanisms are
the bicycle, the adding machine, or the television set.
allows man to extend his capabilities,
calculating ability or his eyes.
Each
.e*
his legs, his
However, in each of these
mechanisms, man provides the initiative, the driving force,
or the direction.
These systems do not constitute symbiosis,
but the mechanical extension of man.
In modern computer centered data processing systems we
find a drastic change from the mechanical extension of man.
Here we find that computers have taken over the greater
portion of the task, and are being aided by humans.
This has
been termed the human extension of machines.
It is the other
end of the man-machine interaction spectrum*
Any humans
present are there to help the machine through maintenance
or the performance of tasks which have proven difficult to
automate.
Such systems are not symbiotic.
which started ou
They are systems
to be fully automatic, but didn't quite
make it. This is the present state of the computer centered
weather central.
An extension of the spectrum, presently under develop-t
ment, is artificial intelligence.
The development of intell-
igence in the computer should remove the need for human aid,
and allow the computer to forge ahead on its own,
Such a
development may well invalidate the need for symbiosis;
however, the age of artificial Intelligence is not yet here,
and it
is anyone's guess when or if it will arrive.
It has
been estimated that it will be 1980 before machines alone
will be able to do muoh useful thinktIng on military problems.
Licklider (1960) has allowed the possibility of up to 500
years.
Another point in the man-machine spectrum is man-*
computer symbiosis.
This is the most advanced means avail-.
able at present for solution of problems requiring the exerelse of intelligenoe.
It is hoped that through the close
coupling of complementary talents of man and computer many
tasks which cannot be handled satisfactorily by either alone
may be approached through cooperative effort.
Symbiosis is
an important development in methods of computer useaGe, for
the tendency in recent times has been to a continual
decrease in man-computer couplinG.
Because of the high
costs of computer operation and volumes of programs to be
run, most computer facilities have instituted the policy of
disoouragin- pro-rammer presence durin2 run.
Instead, pro.
grams are submitted with instructions for operation, and
run in large batches under an automatic system.
hours later the results are returned.
Several
This means that work-a
in.,* with the computer in producinG a problem solution is a
slow and tedious process.
Thus, one way in which manwcompu-&
ter coupling may be judged is by the time it
takes from test
or query submission until results or a reply are fortheoming.
25
Another area in which man-computer coupling may be examined
is the ability of each to communicate complex ideas to the
other.
The goal of symbiosis is to reduce reply time,
increase the ability of man and computer to communicate,
and, as a result, make feasible the close association of man
and computer in problem solution.
It is of interest to examine the types of problems
around which present day computation systems are oriented,
and those which are unfeasible or unattractive as a result.
Present systems require problems in which all eventualities
can be forseen and all procedures preplanned.
For many
purposes this is no disadvantage, but it becomes important
for certain classes of problems, those which are difficult
or impossible to formulate or preplan.
Meteorological tasks
are of this sort.
One type of problem that is difficult to preplan is
one in which a large set of possible occurrences require a
large set of reactions*
Although one may program for a great
number of eventualities, some will be ignored.
Receipt of
unsatisfactory results and corrective programmin3 is a conm
tinual process.
ProGrams requirinG this approach are common
in meteorological data processing.
If the set of unprogram-
med eventualities is large and the time required for one
test is also large, improvement becomes very slow.
Symbiosis,
by cutting down test time, allows us to formulate our problem solution initially in a crude manner and rapidly develop
26
better procedures through trial and error.
Symbiosis can also help us in another way.
Once a
program of the sort described has been developed to the point
where its procedures are fairly adequate, it may be used
operationally.
Although many eventualities will not have
been found, through our close cooperation with the computer
we can monitor (quality control) its actions and take manual
corrective action if the need arises.
The information
gained can be used later to improve the proGram.
If the
problem is completely programmable (forseeable or formulatm
able) this second phase will become unnecessary.
From all
indications most meteorological tasks will require such
monitoring,
Another type of problem which is difficult or impossible
to handle with present data processing methods are those
which include eventualities or actions which are too oomplex
to be easily described.
Here, the monitoring aspect of
symbiosis is the most important, for we find that we are
completely unable to formulate the problem in machine terms.
In such problems the human is able to fill the cap.
An
example of this type of problem is one which includes reoogenition of complex patterns, i. hurricanes, frontal systems,
air mass types.etc.
In summary, symbiosis is important for problems whose
method of solution is difficult or impossible to formulate.
Solutions to such problems are usually an approximation to
a "best" solution.
Thus, we can look on the process of
27
formulation as one of hill climbing- or maximization of ability.
Short test time allows one to approach the top more
rapidly.
The closeness with which a best solution can be
approached is determined by the undiscovered aspects of the
problem.
In any case, an only partially satisfactory solu-
tion may be used since a human may now fill in the gaps in
its methods.
In the gap filling process it may be possible
to learn ways to improve the program.
3.1 PROBLEM AREAS FOR MAN-COMPUTER SJBOSIS
Now that we have looked at the many reasons why mancomputer symbiosis is desirable, the obvious question arises:
why hasn't it been done?
The answer is to be found in the
differences between man and computer.
Some of the same
4ifferences which make symbiosis attractive are those which
make its realization difficult.
The first difficulty to be
examined is that of speed.
Everyone knows that computers are fast, and Gettingr
faster4
With speed comes expense.
The result is that it can
be a very expensive proposition to make a large digital computer wait for a human to take some action.
This is pre-
cisely why most present data prooessing systems do not allow
stops and why loading and input-output functions are done
without human intervention.
For many purposes, the lack of
human intervention is a good idea, but how can we economically allow such intervention when it is necessary?
The
28
answer is time sharing.
This new approach to computer use
is presently in operation, and being developed further, at
M.I.T.
Time sharing allows many users to share the available
computer time in an efficient manner.
It is essentially an
automatic time allocation program which distributes run time
to other programs, under a priority system.
Through such an
approach it is possible to allow any one program to pause
and wait for human help, and still be economical, for now
another program can be utilizing the time.
In other words,
instead of one program having complete control of the computer, a pool of programs to be run are available to a time
allocation program.
inactive programs.
The pool is divided up into active and
Inactive programs are those which are
waiting for human help or for an input-output device to complete some job.
time.
These cannot immediately use computation
Active programs are those which can immediately util-
ize computation facilities.
Active programs are run for
short periods of time in a round robin fashion, under a
priority system.
The priority system is usually such that
man-computer interaction programs receive first attention.
Thus, computer reaction to human action is rapid.
Programs
not requiring man-computer interaction are run at a lower
priority, filling in when all other programs are waiting.
As can be seen from the above description, time sharing
makes mandatory the availability of large-volume, high-speed
29
storage facilities for keeping the pool of programs.
In the
past this was a difficult requirement to satisfy, but the
use of the IBM 1301 disk file (available at both centrals)
fulfills this need.
There are other problems in making time
sharing an efficient process, but it is interesting to note
that many of the characteristics of operational weather data
processing simplify time sharing.
For example, the fact that.
the programs being time-shared are operational and, as a result, fairly predictable as to size and actions, can reduce
difficulties.
In the time sharing systems being developed
at M.I.T., it, is assumed that the programs being run are unknown and untested.
Furthermore, in an operational set of
programs the use of input-output devices may be preplanned,
whereas, in a general time sharing system the input-output
devices must be allocated by the system.
Thus, because of
its operational character, the problem of providing time
sharing for an operational weather data processing system
should be a reduced problem.
The second major difficulty in the realization of
symbiosis is provision of the ability for man and computer
to communicate effectively.
This problem has two phases:
1) input-output devices
2) flexible man-computer language
The problem of providing hardware for a man-computer communication link is one which has received considerable study
by those developing command-control consoles.
Available
~
m
I
-
devicea, although adequate to handle the job, are not yet
in a really desirable form.
At present the best available
means for communication is the use of a cathode ray tube
(abbreviated CRT) with light-pen and typewriter.
More advan-
tageous would be a system which allowed verbal instead of
typewritten communication, and had a surface for visual
display of a higher capacity than the present cathode ray
tubes.
Presently available equipment can do the job, however,
with some limitations.
It is important to mention at this
point that to be useful the CRT display must be self-maintaining and dynamic.
If the computer must be tied up by the
display process, then it cannot be doing useful labor, and
the result is an uneconomical use of the machine and no need
for time sharing.
The display must be dynamic so that light-
pen techniques may be used.
A further desirable feature for
the CRT device is the ability to display curved and straight
line segments, as well as points.
It is possible to do num-
erous weather processing tasks with devices which lack some
of the capabilities mentioned above (see section 4 of this
thesis).
The second phase of the man-computer communication
problem is the language.
Here again, the fact that we are
working with a limited set of problems gives us an advantage.
The symbol system used in operational weather forecasting
is well defined, because, since the beginning of weather
service it has been necessary to transmit symbolic information
A
31
about~Weather over mechanical devices.
As a result, meteor-
ologists are well trained in the use of the set of symbols.
Furthermore, the kinds of operations necessary for increasing
the accuracy of operational weather forecasting do not seem
to present a formidable obstacle.
Ultimately, it may be
possible to allow extremely sophisticated man-computer
symbiosis in meteorology through the development of advanced
languages, but this is unnecessary for the purposes being
described here.
~--~
~
32
4. FES4BILITY OF METEOROLOGICAL SYMBIOSIS
IA.attempting to demonstrate the ease with which a
symbiotic use of the computer may be achievved in meteorology,
it was decided to examine the problem of isopleth display
and manipulation as a means for control of grid data arrays.
Cathode ray tube display devices have been utilized for the
display of well defined symbols (alphabetic, numeric, etc.)
and graphs for some time.
Thus, it was felt unnecessary to
investigate the manipulation of coded reports (as they appear
on teletype) or plotting of aerological diagrams, since
similarity to present uses promises easy development of
symbiosis.
Considerable work has been done recently in the use
of the computer and cathode ray display in computer aided
design at M.I.T.
Work by Sutherland (including a movie) gives
an exciting look at the potentialities of such systems in
the manipulation of geometric figures and diagrams.
However,
Sutherland's work involved the use of circles and straight
lines, but no arbitrary curves such as are found in meteorological isopleth patterns.
Although there was no hope of
achieving equivalent flexibility in the present project, it
was felt that an investigation of the manipulation of curves
would be a fruitful addition to Sutherland's contribution.
The problem, as initially conceived, was the development
of sohisticated means for modification and control of grid
data fields.
These are one of the most common forms of data
used in computer weather
data processing.
Isopleth
modification is not the only approach to this problem, nor
is it the simplest.
One simple way of achieving success at
grid field modification would be to allow the choosing of a
subset of grid points through the use of the light-pen, and
then to cause a constant quantity to be added or subtracted
from the field values at those points.
Another simple
approach would be to allow the addition to the field of a
positive or negative point vortex at a position defined by
the light-pen.
Another method, suggested by normal analysis
techniques, is the creation of a hypothetical station report
to correct a grid region.
Isopleth modification seems to offer the most effective
means of grid data control.
The isopleth pattern is, in a
sense, a summarization of the character of the field.
If we
could modify the grid field through redrawing of the isopleths we would have flexible control.
Another argument for
the direct modification of isopleth patterns is that such
patterns are the primary symbolic method through which a two
dimensional mapping of a quantity can be represented to the
human mind.
Thus, changes necessary to isopleth patterns,
interpreted as movement of position, tend to be more obvious
to the human than quantitative changes of the grid values or
vorticity.
4.1 THE COMPUTER
Problems were encountered in trying to choose a computer.
Time sharing is available only on the Computation Center
34
7090 which does not have a light-pen associated with its
cathode ray display.
Further, no computer at M.I.T. has a
The CRT on the TX-2
CRT with self maintaining display.
computer at Lincoln Laboratories (used by Sutherland) does.
Thus, since the program to be written was obviously going
to waste time, it was decided to program it on the TX-0
(a small computer available for student use), which has the
fastest display time (approximately 40 microseconds per
point) of any computer at the Institute.
4.2 THE PROGRAM
The program starts with a seventeen by seventeen grid
point array, and produces contour lines for the resulting
256 grid areas through a linear interpolation method.
The
CRT display device on the TX-0 displays discrete points only,
so it is necessary to display curves as collections of points.
Not all the points available on the tube face (5122) are used,
due to limitations of display speed.
Instead, sixteen points
(four by four) per area for the 256 (sixteen by sixteen)
grid areas are used.
If too many points are displayed, the
amount of flicker becomes irritating.
The locations (on the tube face) of points to be
displayed are stored in two ways.
Display storage is a table.
holding one tube face position per word.
Each word uses the
left nine bits to represent the X coordinate and the right
nine bits to represent the Y coordinate, just filling the
35
eighteen bit word.
In this configuration the locations are
ready for immediate display by simply loading them into the
accumulator and giving a display instruction.
However, this
storage configuration makes magnification changes difficult.
Thus, a codeword storage is used.
The codeword store uses
one word per grid area, sixteen bits of the word representing
each of the sixteen possible point locations in the grid area.
This allows very compact (256 words) picture storage, which
is unaffected by magnification or centering changes.
To create point positions for display, the codeword
storage is unpacked.
Using magnification and centering
information from the switches, a tube face location for
each point is computed.
for efficiency and speed.
These are stored in display storage
Each time that the magnification
or centering settings are changed, the display storage must
be completely erased, and the new point locations computed
using the codeword store and the new settings.
Display modification is accomplished through use of
the light-pen.
The light-pen is a photocell which sets a
relay when it sees a point displayed.
Thus, after each point
is displayed, a test must be made to see if the light-pen has
reacted.
Tracking the light-pen is achieved by the plotting
of vertical and horizontal lines of points in four directions
from the last known position of the pen.
The average of the
four first unseen point locations in the four directions is
the new pen position.
36
-not seen
horizontal average
old pen position
not seen---+
0
0
0
+
0 *--not
seen
-vertical average
%-area "seen" by
light-pen
new pen
position
*
i-eot seen
figure 5
Tracking the pen allows us to draw curves on the tube face.
Seeing a point which makes up a displayed figure can be
used to erase that point, or to find the position of the pen
to initialize tracking.
Another method of finding pen
position is the display of points in random positions over
the tube face until one is seen.
The program has two modes of operation, drawing and
erasing.
In the drawing mode (set by a swit-ch) the computer
displays the full contents of the display storage watching
for a reaction from the pen.
If another switch is on, 100
randomly located points are displayed after each pass through
display storage, also looking for the pen.
found, tracking begins.
When the pen is
The tracking cross must be displayed
often, so only eighteen points from display storage may be
shown before the cross must be plotted again.
To produce a
set of points which represent the track, the program remembers the first location where the pen was seen.
As each new
37
pen position is computed, this remembered position is displayed.
If it is still in view, the new pen position is
used only for tracking.
If the remembered location is no
longer visible, the new pen position replaces it, and the
new position is stored in both display and codeword storage.
The other mode of operation is the erase mode.
Display
storage is again plotted on the tube, but now, when the pen
reacts, the position is erased from display storage.
The
codeword storage representation of the point is erased by
removing a bit from a storage location which is computed
from the magnification and centering settings.
4.3 RESULTS
Figures 6 through 13 show how the on-line display looks.
Figures 6, 7, and 8 show an unmodified contour pattern for a
grid array computed by taking the radial distance from the
center of the grid.
Three different magnifications are shown.
Figure 9 is a double exposure of the same set of contours
with a portion erased.
Figure 10 shows the contours from 9
with a trough added (drawn in with the light-pen).
Figures
11 and 12 are the same circular contour pattern, but with
more contours used.
Figure 12 shows an extreme example of
the amount of magnification possible.
Notice the relative
sizes of the center square in the two versions.
was drawn free hand.
Figure 13
figure 6, contours for a radial field, at minimum size
figure 7,
contours for a radial field, at standard size
(display size equal to size of tube face)
39
figure 8, contours for a radial field, at high magnification
figure 9,
double exposure (minimum and standard size) of
contours from figure 7 with a portion erased
40
figure 10, double exposure (high and low magnification) of
contours from figure 9 with trough drawn in
figure 11, contours for a radial fiJeld, standard sime
more contours than previous figures
with
figure 12, double exposure (high and low magnification) of
contours from figure 11 with small square added
figure 13, free hand drawing
42
Some difficulty is encountered in representing a curve
as a set of points on the predetermined grid of display locations.
The process of moving from the actual pen track to
the grid often gives an uneven appearance to the line.
This
difficulty is mitigated by the fact that eras'ing ii-extremely
easy and accurate, so that rough contours can be smoothed.
Such work is especialiy easy at high'magnifications.
In
operational curve-drawing programs, considerable work could
be done in constraining-lines to be smooth curves.
However,
even with this'relatively unsophisticated program it was
possible to modify displayed patterns with ease.
The final phase of the problem was to have been the use
of the new contour pattern to modify the original grid values.
Considerable difficulty was encountered, and this was not
completed.
It was felt that although this two dimensional
fitting of a surface to the contour pattern is difficult, it
is solvable, and contributes little to a demonstration of the
usability of isopleth modification for man-machine interaction in meteorology.
In an operational system using the approach described,
it would be mandatory to have a self-maintaining, highcapacity display, such as that on the TX-2.
Further import-
ant additions to the isopleth display and modification would
be the overlaying of other maps which could not be erased or
modified.
Such overlays could include geographic maps to
indicate location of the pattern, station models (as normally
43
plotted on weather analyses)-for the purpose of checking of
analysis validity, or, in the case of forecasts, a continuity
map (a map of the contours of the initial value of the
quantity being forecast).
Further developments must also be attempted in the use
of topological and mathematical constraints on contour
patterns.
Sutherland's work in automated design achieved
great flexibility through the uise of such constraints.
The
application of similar principles to contour patterns offers
great possibilities, but will require considerable labor.
44
5* THE WEATHER CENTRAL OF THE FUTURE
Using the approaches which have been described thus far,
what should a weather central of the future look like?
First
we will look at the problem from the standpoint of equipment.
5.1 EQUIPMENT
One of the prime concerns in our system must be that
of dependability.
This requires the use of redundant compon--
ents so that if component A fails, component B may take on
its job, slowing the system to half speed, but not stopping
It.
In the choice of central computers, we have an attrac.
tive set of possibilities.
Present computerized weather
use the 7090, so that much programming is available for this
machine.
It is most desirable to retain the ability to use
presently available proGrams, since a massive amount of labor
was involved in their development.
However, the use of two
7090 or 7094 computers is an unreasonably expensive proposition, unless such a computation facility were to be used
by many agencies.
Our set of choices has been increased by
the recent introduction of the 7040 and 7044 computers which
are considerably slower and less expensive than the 7090 or
7094.
The real advantaGe of these new computers is that
certain configurations which are available make them nearly
identical to a 7090, except for speed.
Comparative cycle
times are; eight microseconds for the 7040, 2.5 microseconds
for the 7044, 2.2 microseconds for the 7090, and 2.0 microseconds with instruction overlap on the 7094.
45
Thus, through a building block approach, almost any gradation of computing power and expense can be achieved, with-m
out making the program library obsolete.
This allows us to
use redundancy without making a phenomenally expensive
system.
The most likely choice appears to be the use of two
7044's, each with 32,768 memory locations and extended
instruction set.
Careful study must be made of the cost, access time,
reliability, and volume of storage necessary.
At present
the use of IBM 1301 disk files along with magnetic tape
storage for lower speed capability seems to provide the best
approaoh, but in the future new types of memories (such as
thin films) may make new approaches more attractive.
Redunw
danoy considerations require the availability of at least
two disk units, accessible by all the central computers,
and possibly by direct data devices.
Besides the necessity.
for large volume storage due to the quantities of data to be
handled, such storage .also becomes necessary in the efficient
use of time sharing and the storage of programs which must
be easily available.
Another problem occurs because self-
maintaining displays often require considerable storage,
sometimes associated directly with the display'equipment.
An example of this use of storaGe is the SM-2A cathode ray
tube display system developed by Laboratory for Electronics.
This system uses a flexible disk to store the elements to be
displayed on the tube face.
46
As more economical means are found for storage of eleo..
tronic information, it will become practical to stop turning
out paper products.
The reasons for taking such a step are
found in the increased flexibility of operations which can
be performed on electronically displayed information, and in
the ease of retrieval of such information.
For example, it
may be possible to have all the grid maps for the past year
stored on magnetic tape, and to display on a console a set
of contours of the change between two grids by simply asking
the machine to display one minus the other.
Such an idea
may take a while to automate, but it results in a man being
able to use the cathode ray tube and light-pen as pencil and
paper, with the direct assistance of the computer in retriev-irn
information and doing mathematical and meteorological
operations.
The equipment must also include at least two interac-'
tion consoles, of the type described earlier.
The cathode
ray tube must have the ability to display large amounts of
information rapidly enough to avoid flicker, for many
meteorological displays will contain considerable detail.
Equipment will also be needed for the direct input of tele-type data.
The use of a satellite computer or special
device for this purpose can invalidate our reliability
arguments if it is not redundant.
Thus, it seems most prac-
tical to time share the input processing on the main computers, rather than squander money on redundant inputprocessing computers.
At any rate, the initial data
collection device must be extremely reliable, for its failure can halt the whole system,
5*2 PROGRAMMING
Ultimately it is hoped that weather centrals will become
entirely computer aided.
All the operations should be able
to be carried out by the computer and several meteorologists
workinG at consoles.
No paper of any kind will be necessary.
All necessary information will be stored and retrievable by
the computer.
Such information will be easily displayable
on any of the consoles, in any magnification desired, and
in relation (overlayed, subtracted, added, etc.) to other
information.
During operational forecasting runs one console will
be operated by a data expert.
teletype data as it
Before him will be displayed
is normally printed.
However, instead
of being required to examine every report, the data expert
will see only those reports or bulletins which the machine
finde difficult to handle.
This man will also monitor, with
tho machine's help, a display of the available coverage.
If
any area is notably deficient, he wil recover bulletins from
that area and see why no data was available.
If garbling
was the problem, he will correct sufficiently to allow the
machine to recover the data.
If no reports were available
from that area, he will request data from his source stations.
Another console will be operated by a meteorologist
who will monitor the physical consistency of the data.
He
A
48
will look at vertical plots of reports which have seemed
unreasonable to the machine.
He will monitor the analysis
process, and examine reports which the machine feels to be
in error.
When such reports also seem in error to him, he
will request that the data expert examine the source report
for garbling.
Finding none, he will look at the vertical
consistency of that report.
Finally he will have the choice
of accepting or discarding the report.
The meteorologist
will also aid the machine in the recognition and traoking
of phenomena, such as hurricanes, fronts, the jet stream,
highs, lows, etc.
At forecast time he will monitor the
actions of the foreoasting scheme, making sure that unreasonable patterns do not result, and aiding in the placement
of the phenomena which he helped to recognize during the
analysis process.
Once he is satisfied with the forecast,
he will give his approval, and the data will be stored until
transmission time when it will be retrieved and transmitted
automatically.
This description has been intended only to indicate
the kinds of thingfs that we can hope to achieve.
Actual use
of such a system will probably not be limited to operational
problems, and may not be exactly of the sort described.
Admittedly, the system described is the work of many years.
CominG back to the present, it is necessary to examine a step
by step process whereby symbiosis may be instituted in
weather data processinG, without completely discarding
49
present systems.
As time progresses, the success or fail-
ure of the initial steps will indicate the degree to which
a more advanced symbiotic system is useful and realizable.
The first step must be a large one, but not as larGe
as might seem to be indicated by some of the earlier dis-.
oussion.
Redundancy of components is not a necessity.
It
has been presented here because it seems foolhardy to build
a powerful system upon which one may become dependent, if
it is not also to be reliable.
connected with symbiosis.
However, redundancy is not
Symbiosis may be achieved on
present weather central computer systems (7090 with disk
file and maGnetic tapes) by the addition of a man-computer
communication console and some programming.
To date, the
prooessing area which seems to offer the Greatest possibility
for improvement by human intervention is the initial processing of data, i. before forecasting begins.
Thus, a
good initial step might be to add human intervention to the
programs in this phase, and develop and test a time sharing
system for them.
,
As the time sharing programminG becomes more general,
symbiosis may be extended to all aspects of operational data
prooessin.
If real-time data input is developed, this too
may be time shared.
At this point it will be feasible to
begin to automate jobs which have not been put on the computer
because a considerable amount of human labor must be utilized.
Such jobs can be computer aided throuGh the use of the interaction consoles.
As this development of the use of symbiosis
50
in all phases of forecast1.ng nears completion, there will
be no need for paper products (maps, teletype printout, etc.).
To develop the use of symbiosis to this degree will require
the use of sophisticated information storage and retrieval
techniques, for we will wish to have available both data and
programs in great quantity and variety.
It will also require
the development of a language for speoifyingr the data fields
and operations with which we wish to achieve some goal.
Thus, although the ultimate system may be presently unattain-.
able, the first steps can be taken easily and still provide
necessary increases in the quality of operational products.
REFERENCES
Computer Charaoteristics Quarterly, Adams Associates, December
1962.
Coons, S.A., "An Outline of the Requirements for a Computer
Aided Design System," Collected Papers of the Session
on Computer Aided Design, Spring Joint Computer Con-ference, Cobo Hall, Detroit, May 23, 1963, 14 pages.
Fawcett, Edwin B., "Six Years of Operational Numerical
Weather Prediction," Journal of Applied Meteorology,
vol. 1, no, 3, Sept. 1962, pp. 318 - 332.
Grisoff, S.F. "The M.I.T. Time Sharing System, A Preliminary
Report, IBM memorandum, April 16, 1962.
Licklider, J.C.R., "Man-Computer Symbiosis," I.R.E. Transaotions on Human Factors in Electronics, vol. HFE, March
1960, pp. 4
-
10.
Licklider, J.C.R., and Clark, W., "On-Line Man-Computer
Communication," Proc. of the Spring Joint Computer
Conference, San Francisco, Cal., vol. 21, May 1 - 3,
1962, pp. 113
Loewe,
-
128.
R.T., Sisson, R.L.
Generated Displays,
pp. 185
-
and Horowitz, P., "Computer
Proo. of the I.R.E., Jan. 1961,
195.
Reference Manual, IBM 7040 and 7044 Data Processing Systems,
I.B.M. Corporation, 1961.
Sutherland, I*E., "Sketohpad, A Man-M4achine Graphical
Communication System," PhD Thesis, M.I.T. Dept. of
Electrical Engineering, January 1963.