Time Lapse Photography of Clouds

V. J. Schaefer

The equipment and procedures used in preparing more than 15,240 m of 16-mm time lapse movies of at-mospheric clouds is described. Such photographic records are of great value in establishing a dynamiccloud census of a specific area. Operational techniques, the support diagrams, and the optimum timeintervals in use for different types of records are presented.

Introduction

Time lapse photography is a powerful geophysicaltool. Many spectacular results have been achievedduring the past few years, ranging from the diurnalcloud motions on planet earth, as taken by the APTSatellite, to the growth of columnar frost emerging frommoist, cold soil.

In the field of cloud photography the preparation of aseries of 16-mm reels showing all types of clouds in timelapse was prepared during the period 1953-1958 undersponsorship of the Munitalp Foundation.' This pioneereffort resulted in the assembly of more than 15,240 m ofexcellent time lapse footage taken in many parts ofthe world. Ten-camera units were dispersed to suchplaces as Germany, Sweden, England, Japan, Antarc-tica, Labrador, Hawaii, Hong Kong, Kenya, as well asFlorida, New Mexico, Arizona, Wyoming, California,Colorado, Montana, Idaho, Washington, Connecticut,and New York.

Since the time lapse camera units needed to be op-erated under a wide variety of climatic conditions andby persons ranging from scientists and technicians toranchers and housewives, it was essential that a rugged,simple, long-lived, foolproof, and relatively inexpensivecontrol unit and camera be assembled. Since it alsohad to be transported to many parts of the world, theentire unit was packed in a fiberboard container alongwith power supply and an adequate film supply.

The camera used was a Model 200 Bell and Howell 16-mm magazine type of camera. This was equipped witha shutter control which exposed a single frame that thuscould be actuated with a solenoid counter. A type DW68 General Electric exposure meter was part of the basicequipment, aswas a 17-mm,f/2.7 lens and viewfinder. Asimple Linhof Report Miodel tripod equipped with a

The author is with the Atmospheric Sciences Research Center,State University of New York, Albany, New York 12203.

Received 15 March 1970.

Graig model tilthead and a stenographer's notebookwith black crayon for use as title board completed theassembly of equipment. The time lapse control (seeFig. 1) was designed for me by Dr. John Bellamy Tay-lor, a retired General Electric Company electricalengineer, whom I interested in this type of photography.As designed, the control was rugged and simple andprovided time intervals ranging from two frames asecond to one in 10 sec. The time interval wasvaried with a 10,000-2 potentiometer, which was part ofthe basic circuit. A No. 5308 Burgess 45-V battery wasgood for more than 250,000 operations (more than 1829m of film).

As assembled and with ten 30-m unexposed filmmagazines including film processing shipping cartons,the complete unit packed in its fiberboard carrying case(which could be shipped by air or rail express) weighed20 lb.

Ordinary Clouds

One really can obtain very little feeling for thedynamic processes of atmospheric clouds without theuse of time lapse photography. At the outset thephotographer faces the dilemma of what time intervalshould be used. If two or three frames a second are used(contrasted to 16-20 frames/sec, as used in silent orsound film photography), there is still the chance thatthe cloud motions will be slow and the result not muchbetter than the normal motion picture. This is espe-cially true for stratus, cirrus, fog, and smog formations.If, on the other hand, a long interval, such as 6-10 sec, isused, some of the most interesting formative details,especially of the cumulus and wave cloud types, may bemissed.

After a considerable amount of experimentation, atime interval of one frame every 2 see was adopted andused for all general cloud photography during theMunitalp program. Since there are forty frames in0.34 m of 16-mm film, a time lapse interval of 2 seecaptures a 20-min cloud sequence on 4.5 m of film. Longexperience during the Munitalp activities with all types

August 1970 / Vol. 9, No. 8 / APPLIED OPTICS 1817

Fig. 1. Electrical diagram. 1-45-V B #5308 Burgess, 2-Switch A-H&H X 3-A 250 V, 3- 50-V, 500-F Beaver capacitor#5050 BRH Cornell Electric, 4-Relay 5000 , 28000 turns Q41E.D.C.P., Clare Co., Chicago, 5-Potentiometer Mallory M1OMPX, 6-Socket, 7-Plug, 8-Solenoid Counter Mercury

MlEA-N5-6D, Chicago Production Inst. Co.

of cloud sequences showed the 2-sec interval to be anexcellent compromise.

Most clouds have formative cycles lasting from 10-20min. If the cloud develops into a giant formation, alonger sequence should of course be made, continuinguntil the growth and dissipation cycle is completed.Under ordinary operation the Model 200 camera whichwas used will drive about 4.8 m of film with one windingof the spring drive. It is good practice, however, to re-wind this mechanism every 7 or 8 min. This is easilyachieved by winding with short twists between the 2-secexposure sequences. It is also important to note thegeneral motion of cloud patterns so that the subjectselected tends to move across or away from the framedview. If the main subject of developing interestreaches the edge of the viewfinder, the camera azimuthand elevation should be altered in small, but uniform,movements, not more than a degree per exposure. Thiswill provide a smooth and logical reorientation of thesubject as photographed.

These recommendations imply that the time lapsecamera operating at 2-sec intervals should be attendedthroughout the camera operation. This is an essentialand extremely important feature in the preparation ofgood sequential time lapse records. To obtain goodsequences that will provide an excellent cloud clima-tology does not require more than an hour or two ofclose attention for each cloud type available in an area.A good collection for a given locality will thus consist ofabout ten 122-m reels of cumulus (2 reels), stratus (1reel), cirrus (2 reels), fog (1 reel), pollution (1 reel),optical effects (1 reel), jet stream clouds (1 reel), andfrontal storms (1 reel). The preparation of 1220 m ofreally good sequences will require the exposure of about1524 m of film. This represents one hundred 15.24-mmagazines requiring about fifty 2-h days of cloudphotography a year over a period of three years.

Three-Dimensional Views of Cloud Systems

An excellent picture of the spatial distribution ofclouds over the earth can be obtained from an airplane2

by mounting the time lapse camera at right angles to theflight path. If possible, the camera should be locatedopposite the sun. The angle of the camera should pro-vide that about a sixth of the top part of the picture isabove the horizon.

A cloud sequence taken in this manner provides amarvelous sense of the three-dimensional array of acloud system, since those near the plane appear to moveby at a much greater velocity than those in the distance.It is also feasible to take sequential frames for fairlygood three-dimensional viewing.3

Lenses for Time Lapse Photography

After a considerable amount of experimentation a 17-mm, f/2.7 Wollensak Raptar camera lens was selected.It was fitted with an ultraviolet filter, which also servedto protect the nonreflective coating. For special studiesa 25-mm, f/3.5 and a zoom lens have been utilized.

In one series of experiments a large transparent 25.5-cm glass sphere filled with alcohol was utilized for moni-toring general cloud systems. This is a very effectivemethod for obtaining a very inexpensive 1000 view ofthe sky and the surrounding countryside. Since rela-tive and detailed cloud motions are of less importancethan the general pattern, a time interval of one frameevery 2 min was utilized using a 2-min timing switch forthis purpose. It was this assembly mounted on top ofmy house that provided the photographic evidence ofthe formative stages of the devastating Worcestertornado. 4

Climatic Studies in Time Lapse

A few experimental runs have been made to determinethe usefulness of the time lapse technique for the prep-aration of a climate record. A 15-min time intervalwas chosen so that, in a 10-h day, each day is repre-sented by 0.61 m of film. This amount of footage isadequate to provide an excellent record of the cloudtypes (or lack of clouds) and the other climatic featuresof a particular region.

Predawn, After Sunset, and AfterDark Time Lapse

By simply rotating the circular shutter of the Bell andHowell Model 200 camera by a half turn, it is feasibleto use the camera for long exposures. Thus byusing the 2-sec interval as the exposure period and thelens diaphragm as light control, it is possible to obtaingood footage for nearly an hour before sunrise and aftersunset. A series of such sequences were obtained for mefrom the summit of Mauna Loa on the island of Hawaiiby Dr. Nakaya of the University of Hokkaido. Theseshowed some extremely interesting clouds and opticaleffects.

The same camera was also used to obtain an excellentrecord of the lightning distribution pattern of nocturnalthunderstorms. By holding the lens open until a

1818 APPLIED OPTICS / Vol. 9, No. 8 / August 1970

lightning flash occurred and then immediately shiftingto the next unexposed frame, a vivid record of thelightning occurrences was obtained. Since strikesrarely occur more often than once a second (once in 10sec is the more common interval) and persist in a lo-calized area for 20 min or so, it is quite feasible tomonitor the storm using the simple expedient of justoperating the single exposure trigger. In fact, in anemergency it is possibile to take regular time lapse usingthis method if you have sufficient patience!

References1. V. J. Schaefer, Weatherwise 6, 3 (1953).

2. V. J. Schaefer and W. M. Taylor, Bull. Amer. Meteorol. Soc.38, 206 (1957).

3. V. J. Schaefer, Forest Control Notes 20, 80 (1959).

4. V. J. Schaefer and R. E. Falconer, Bull. Amer. Meteorol. Soc.35, 437 (1954).

Meetings Calendar continued from pge 1816

24-28 Interpretation of Infrared Spectra course, Fisk Inst.N. Fuson, Fisk Inst., Box 8, Fisk U., Nashville,Tenn. 37203

24-28 Ultraviolet and Fluorescence Spectroscopy course,Fisk Inst. N. Fuson, Fisk Inst., Box 8, Fisk U.,Nashville, Tenn. 37203

24-28 3rd Int. Liquid Crystal Conf., Berlin G. H. Brown,Kent State U., Kent, Ohio 44240

24-Sept. 4 Principles of Optical Communication course, MITE. V. Hoversten, Dept. of Elec. Eng., MIT, Cam-bridge, Mass. 02139

30-Sept. 2 Preparation and Properties of Electronic and Mag-netic Materials for Computers, Statler-HiltonHotel, NYC F. V. Williams, Monsanto Co., 800'N. Lindbergh Blvd., St. Louis, Mo. 63166

30-Sept. 6 Internat. Federation of Societies for Electron Micros-copy, 7th Internat. Congr. of Electron Microscopy,Grenoble G. Dupouy, Lab. d'Opt. Electronique duCNRS, Toulouse, France

31-Sept. 4 Dynamics of Molecular Collisions Conf., ORNLE. Greene, Brown U., Providence, R.I. 02912

31-Sept. 4 Gordon Res. Conf. on Lasers in Medicine and Biology,Kimball Union Acad., Meriden, N.H. A. M.Cruickshank, U. of R.I., Kingston, R.I. 02881

31-Sept. 5 6th Internat. Assoc. for Analog Computation Cong.,Mvlunich J. Heinhold, Technische Hochschule, 2Arcisstr. 21, Munich, Germany

September

4-10 IUPAP 12th Interilat. Conf. on Low TemperaturePhysics, Kyoto Inst. for Solid State Phys., U. ofTokyo, 7-21-1, Roppongi, Minato-ku, Tokyo, Japan

7-10 6th Int. Quantum Electronics Conf., Kyoto H. C.Wolfe, AIP, 335 E. 45th St., New York, N.Y. 10017

7-11 2nd Internat. CODATA Conf., St. Andrews, Scot-land N. H. Robinson, Roy. Soc., 6 Carlton HouseTern., London S.W. 1, England

8-12 Molecular Spectroscopy Symp., OSU K. N. Rao,Phys. Dept., OSU, 174 W. 18 St., Columbus, Ohio43210

13-18 IES Nat. Tech. Conf., Vancouver, Can. P. C. Ring-gold, 345 E. 47th St., New York, N.Y. 10017

14-15 Symp. on Image Quality Evaluation, RIT, Rochester,N.Y. R. P. Cook, Polaroid Corp., 730 Main St.,Cambridge, Mass. 02139

14-16 Electronic Spectroscopy, Oxford IPPS, 47 BelgraveSq., London, S.W. 1, England

14-18 Science and Technology of Information Display,tutorial seminar, PIB, Farmingdale H. Warren,PIB, L.I. Grand Ctr., Rte. 110, Farmingdale, L.I.,N.Y. 11735

14-18 SPIE 15th Ann. Tech. Symp. and Exhiborama, Ana-heim H. F. Sander, SPIE, 216 Avenida del Norte,Redondo Beach, Calif. 90277

14-18 4th Czechoslovak Spectroscopic Conf. E. Plsko, Dontechnicy SVTS, Zilina-Hliny, post. priec. D-28,Czechoslovakia

14-19 Transmission Electron Microscopy course, UCLAP.O. Box 24902, U. Ext., UCLA, Los Angeles, Calif.90024

14-25 Spectroscopic Techniques in Organic Chemistrycourse, UCLA P.O. Box 24902, U. E-xt., UCLA,Los Angeles, Calif. 90024

15-18 Conf. on Gas Discharges, London IEE, Savoy Pl.,London, W.C. 2, England

17-18 Low Light Level Imaging Systems, tutorial seminar,Airport Marina, Los Angeles SPSE, 1330 Mass.Ave. N.W., Washington, D.C. 20005

21-25 Applications of Glasses, Glass-Ceramics, and Amor-phous Films in Electronics course, UCLA P.O. Box24901, U. Ext., UCLA, Los Angeles, Calif. 90024

21-26 Scanning Electron Microscopy course, UCLA P.O.Box 24902, U. Ext., UCLA, Los Angeles, Calif.90024

22-24 Electro-Optical Systems Design Conf., N.Y. Coli-seum, NYC R. E. Kinville, ISCM, 222 W. Adans,Chicago, Ill. 60606

27-Oct. 1 ASTM, St. Louis, Mo. ASTM, 1916 Race St., Phila,Pa. 19103

28 Symp. on the Teaching of Optics, Diplomat Hotel,Hollywood, Fla. J. A. Sanderson, OSA, 2100 Pa.Ave., N.W., Wash., D.C. 20037

28-30 10th Conf. on Thermal Conductivity, Boston R. P.Tye, Dynatech R/D Co., 17 Tudor St., Cambridge,Mass. 02139

29-Oct. 2 Optical Society of America, 55th Ann. Mtg., DiplomatHotel, Miami, Fla. J. W. Quinn, OSA, 2100 Pa.Ave., N.W., Wash., D.C. 20037

30-Oct. 3 Amer. Roentgen Ray Soc., Miami Beach, Fla. T. F.Leigh, Emory U. Clinic, Atlanta, Ga. 30322

Fall

? Experimental Methods for Investigating the ChemicalBond in Solids, Aachen Ges. Deut. Chem., Geschafts-stelie, 6000 Frankfurt (M), Postfach 119075, Germany

continued on page 1880

August 1970 / Vol. 9, No. 8 / APPLIED OPTICS 1819