MESOMETEOROLOGY PROJECT - - - RESEARCH PAPERS l. • Report on the Chicago of March 4, 1961 - Rodger A. Brown and Tetsuya Fujita

2. • Index to the NSSP Surface Network - Tetsuya Fujita

3. • Outline of a Technique for Precise Re ctif.cation of Satellite Cloud Photographs - Tetsuya Fujita

4. • Horizontal Structure of Mountain Winds - Henry A. Brown

5. • An Investigation of Developmental Processes of the Wake Depression Through Excess Pressure Analysis of Nocturnal Showers - Joseph L. Goldman

6. • Precipitation in the 1960 Flagsta!f Mesometeorological Network - Keruteth A. Styber

7. •• On a Method of Single- and Dual-Image Photogrammetry of Panoramic Aerial Photographs - Tetsuya Fuj ita

8. A Review of Researches on Analytical Mesometeorology - ·Tetsuy.a Fujita

9. • Meteorological Interpretations of Convective Nephsystems Appearing In T IROS Cloud Photographs - Tetsuya Fujita, Toshimitsu Ushijima, William A. Hass, and George T. Dellert, Jr.

10. Study of the Development of Prefrontal Squall-Systems Using NSSP Network Data - Joseph L. Goldman

11. Analysis of Selected Aircraft Data from NSSP Operation, 1962 - Tetsuya Fujita

12. Study of a Long Condensation Trail Photographed by TIROS I - Toshimitsu Ushijima 13. A Technique for Precise Analysis of Satellite Data; Volume I - Photogrammetry (PUblished as MSL Report No. 14) - Tetsuya Fujita

14. Investigation of a Summer Jet Stream Using TIROS and Aerologlcal Data - Kozo Ninomiya 15. Outline of a Theory and Examples for Precise Analysis of Satellite Radiation Data - Tetsuya Fujita

16. Preliminary Result of Analysis of the Cumulonimbus Cloud of Apr il 21, 1961 - Tetsuya Fujita and James Arnold

17. A Technique for Precise Analysis of Satellite Photographs - Tetsuya Fujita

18. • Evaluation of Limb Darkening from TIROS III Radiation Data • S. H. H. Larsen, Tetsuya Fujita, and W. L. Fletcher

19. Synoptic Interpretation of TIROS III Measurements of Infrared Radiation - Firut Pedersen and Tetsuya Fujita

20. . TIROS III Measurements of Terrestrial Radiation and Reflected and Scattered Solar Radiation - S. H. H. Larsen, Tetsuya Fujita, and W. L. Fletcher

21. On the Low-level Structure of a Squall Line - Henry A. Brown

22. . Thunderstorms and the Low-level Jet - William D. Bonner

23. . The Mesoanalysis of an Organized Convective System - Henry A. Brown

24. Preliminary Radar and Photogrammetric Study of the Illinois Tornadoes of April 17 and 22 , 1963 -Joseph L . Goldman and Tetsuya Fujita

25. Use of TIROS Pictures for Studies of the Internal Structure of Tropical Storms - Tetsuya Fujita with Rectified Pictures from TIROS I Orbit 125, R/0 128 - Toshimitsu Ushijima

26. An Experiment in the Determination of Geostrophic and lsallobaric Winds from NSSP Pressure Data - William Bonner

27. Proposed Mechanism of Hook Echo Formation - Tetsuya Fujita with a Preliminary Mesosynoptic Analysis of Tornado Case of May 26, 1963 - Tetsuya Fujita and Robbi Stuhrner

28 . The Decaying Stage of Hurricane Aruta of July 1961 as Portrayed by TIROS Cloud Photographs and Infrared Radiation from the Top of the Storm - Tetsuya Fujita and James Arnold 29. A Technique for Precise Analysis of Satellite Data, Volume II - Radiation Analysis, Section 6. Fixed-Position Scaruting - Tetsuya Fujita

30. Evaluation of Errors In the Gr aphical Rectification of Satellite Photographs - Tetsuya Fujita

31. Tables of Scan Nadir and Hor izontal Angles - William 0 . Boruter

32. A Simplified Grid Technique for Determining Scan Lines Generated by the TIROS Scanning Radiometer - James E. Arnold

33. A Study of Cumulus Clouds over the Flagstaff Research Network with the Use of U-2 Photographs - Dorothy L. Bradbury aro Tetsuya Fujita

34. The Scaruting Printer and Its Application to Detailed Analysis of Satellite Radiation Data - Tetsuya Fujita

35. Synoptic Study of Cold Air Outbreak over the Mediterranean using Satellite Photographs and Radiation Data - Aasmund Rabbe and Tetsuya Fujita

36. Accurate Calibration of Doppler Winds for their use in the Computation of Mesoscale Wind F ields - Tetsuya Fuj ita

37. Proposed Operation of lntrumented Aircraft for Resear ch on Moisture Fronts and Wake Depressions - Tetsuya Fujita and Dorothy L . Bradbury

38. Statistical aro Kinematical Properties of the Low-level Jet Stream - William D. Borute r

39 . The Illinois Tornadoes of 17 and 22 April 1963 - Joseph L. Goldman

40. Resolution of the Nimbus High Resolution Infrared Fadiometer - Tetsuya Fujita and William R. Sandeen

41. On the Determination of the Exchange Coefficients in Convective Clouds - Rodger A. Brown

Out Of Print •• To be published (Continued on back cover) IN- AND OUTFLOW FIELD OF HURRICANE DEBBIE AS REVEALED BY ECHO AND CLOUD VELOCITIES FROM AIRBORNE RADAR ANO ATS-Ill PICTURES

T. T. Fuji ta Department of Geophysical Sciences University of Chicago Chicago, Illinois

and P. G. Black National Hurricane Research Laboratory Atlantic Oceanographic and Meteorological Laboratories ·ESSA Research Laboratories Miami, Florida

1. INTRODUCTION done extensive work on the calculation of echo ve­ locities within Hurricane Edna of 1954, Connie, In connection with the evaluation of past and Diane and lone of 1955, Audrey of 1957, Daisy and future attempts to modify hurricanes, it is neces­ Helene of 1958, Debra of 1959 and Donna of 1960. sary to determine kinematic properties of the hur­ Watanabe (1963) has computed spawinds in ricane circulation. During the 1969 hurricane Nancy of 1961 from a ground based radar on Okinawa . seeding experiment, Gentry (1970) found significant Fujita, et al (1967) using two radars located along reductions in Doppler win.d speed along the -wall the Pacific Coast of Japan computed echo velocities of Hurricane Debbie. Due to the fact that airborne for Typhoon Bess: Doppler winds are measured only along the flight track at the aircraft altitude, it is always de­ Echo-velocity computations from airborne radar sirable to develop methods of wind velocity deter­ pictures are more complicated than those from land mination over the entire area of a hurricane that based radar pictures. Over JO years ago Fujita is being seeded by airplanes . (1959) applied his echo-shifting technique to the computati·on of echo velocities inside Hurricane Explored in this paper are airborne radar pho­ Carrie of September 15, 1957 . Fig. 1 shows 27 echo tographs taken at 10 to 30 second intervals and velocities obtained by placing the position of the geostationary satellite photographs taken at 20 aircraft in each radar picture at the corresponding minute intervals . The time-lapse film-loop tech­ aircraft position given by Doppler nav igation system. nique developed by Fujita is used to trace the echo As Jong as the Doppler fix is accurate, the echo and cloud velocities. Ten minute average echo motion should represent the ground velocity of velocities an·d two hour average cloud ve Joe it i es echoes precisely. Any error in the aircraft posi­ were computed. tion, however, is included in the final echo veloc­ ity because the aircraft motion is eliminated only By combining the echo and cloud velocities com­ by positioning each radar picture at the Doppler puted at approximately the same times it was pos­ position of the aircraft. sible for the first time to obtain a nearly instan­ taneous analysis of the low level and high level ~----·- flow fields for a hurricane over water. As more data become available, it is hoped that s imilar 32N analyses can be made at successive times to enable the time evolution of the flow fields to be deter­ mined and tested for changes due to seeding.

2. COMPUTATlbN OF ECHO VELOCITY FROM AIRBORNE RADAR PICTURES

Due to the · large areal coverage by ai r borne radar pictures, it is extremely useful to determine echo velocities from these pictures. Although echo velocities do not always represen~· the motion of the atmosphere inside which these echoes are im­ bedded, marked changes in echo velocities in rela­ tion to modification attempts .will reveal the affected areas as well as the extent of modifica­ tion.

Land based radar pictures have been used by Fig. 1. Ground velocity of radar echoes within several investigators to determine echo velocities Hurricane Carrie of September 15, 1957. Echo motion inside hurricanes . Ligda (1955) was the first to was computed by placing successive scope pictures do this for the hurricane of 23-28 August, 1949. at the aircraft positions fixed by Doppler radar In his work he coined the term "spawinds", which (Fuji ta 1959) . he used in reference to the velocity of isolated convective eel ls. Senn {1960a, 1960b , 1963) has Jordan (1960), using a different method com- 353 puted the motion of distinct precipitation features velocities with echo motion and aircraft-measured around the eye wall of Hurricane Daisy of 1958. wind in order to learn the motion field covering His technique of computing the echo velocities rel­ the entire regions of a hurricane. ative to the storm center is incorporated into the technique in this paper. 4. COMPOS I TE HURRICANE ECHOES FROM AI RBORNE RADAR PICTURES 3. COMPUTATION OF CLOUD VELOCITIES FROM GEO­ STATIONARY SATELLITE PICTURES The horizontal dimensions of a Debbie-class hurricane are so large that the entire region of Since ATS-I was launched over the equator in the storm can not be covered by a s ingle airborne the Pacific, a number of meteorologists started radar picture. If one desi res to see radar echoes computing cloud velocities from successive ATS pic­ within the entire hurricane area, a series of air­ tures taken 12 to 30 minutes apart. One advantage borne PPI pictures mus t be put together into a of using satellite pictures in computing cloud composite picture. motion is that the traceable clouds extend far be­ yond the region of precipitation echoes in the cen­ Shown in Fig . 3 is a PPI scope picture taken tral region of a hurricane. simultaneously with the ATS-II I picture of Fig. 2. The picture was taken on board Fury J, a U. S. Air Presented in Fig. 2 are the spiral cloud bands Force WB-47 aircraft flying at 39,000 ft. The ra­ of Hurricane Debbie of August 20, 1969 . These dar was the APS-64, a 3.~ cm radar with a peak cloud bands were obtained by enhancing electronic­ power of 40 kw and a csc beam width of 1. 5°. ally the digital signal. They correspond extremely well with the area of radar echoes. Two degree grid lines are superimposed upon the picture to give the storm's position as well as her horizontal dimensions.

- I , ll""' ):6. .t :'. ' I · ~ ~

Fig . 2. An enhanced ATS-Ill picture showing Hurri­ cane Debbie at 1630 GHT August 20, 1969, when the central pressure was 950 mb, the lowest during her 'Fig. 3. A radar picture of Debbie taken at 1630 enti re life. Thi s hurricane was being seeded when GMT, t he time of the ATS -I l l picture. this picture was taken. The plane was flying toward the northwest and Although it is not feasible to distinguish was located approximately 75 n. mi. to the north levels of cloud motion by simply examining cloud northeast of the eye. It will be found in the cells in successive pictures, a time-lapse film picture that the tail attenuation prohibits appear­ produced out of a number of pictures' clearly indi­ ance of echoes to the rear of the aircraft. A cates two-layer motions: high cloud velocities and circular sea clutter is seen around the aircraft low cloud velocities. Thus, we comp uted these cloud position. In view of these characteristics of air­ velocities separately with a degree of accuracy borne PPI pictures, we found that a pie- or more which turned out to be better than 3 kt. correctly a boomerang-shaped area from each of s uc­ cessive pictures must be cut out to produce a com­ There are three di stinct areas of cloud velocity posite radar picture. computation . The first area is given by the white area of enhanced clouds, where practically no mo­ Figure 4 was made by putting together 14 pic­ tion was computed due to very quick changes in en­ tures from Fury J radar taken between 1615 and 1720 hanced cloud cells. The second area consists of GMT at 5 minute intervals. Afte r a composite pic­ outflowing cirrus with s treak patterns superimposed. ture was made, aircraft heading lines were painted Over 50 velocities related to hurricane outflow to avoid confusion with wind vectors which a re were computed in this area. The third area extends superimposed upon this composite picture. outward from the hurricane cirrus shield. Host of the cellular clouds in this area appear to be low There are two groups of wind symbols, the one clouds. plotted along Fury J flight track is obtained from Doppler winds measured while flying at 39,000 ft. It is, therefore, necessary to supplement cloud The second group represents the displacement vectors 354 68"1>· ... ~· - •& •1£ ~ ECHO VELOCIT IES RELATIVE TO ~ ~ ~ A- STORM CENTER A '61$-171'l GMT ~ "'oo "ff :JP- ""°"'' 20., 1'69 "f> ~ 2J J'...... 0 .

Fig. 5. Echo velocities relative to the center of Fig . 4. A composite radar picture covering the en­ Hurricane Debbie . The length of each velocity tire precipitation areas within Hurricane Debbie. vector represents the echo displacemen t during 10- min. periods, 1616-1626, 1625-1635, 1640-1650, and of high clouds computed from a series of 16 ATS-II I 1702-1712 GMT. pictures s tarted at 1437, 1450, 1503, 1516 , 1529, 1542, 1557 , 1610, 1623, 1648 , 1701, 1714, 1727 , The result of the computation , shown in Fig. 5, 1739, 1752, and 1805 GMT on August 20, 1969. If reveals a systematic motion of radar echoes around we assume that the motion of these high clouds rep­ the hurricane center. A quick examination reveals resents the flow patterns near the 39,000 ft . level , that the crossing angles as well as the echo veloc­ these aircraft winds combined wi th these cloud ities are not axiall y symme t ric. In order to pro­ velocities represent an outflow f ield from the top duce scatter diagrams of these values as a function of Hurricane Debbie. of four sectors, crossing angl es and echo speeds were plotted in Fig. 6 which show the distribution When the outflow field exp ressed by wi nd sym­ in t he left, right, front and rear sectors. Four bol s and radar echoes are examined together , i t is sectors were defined by drawing two 45° lines rel­ seen that t he crossing ang le of outflow air is very ative to t he motion vector of t he hurricane center. small over the region of the inner as Although the distribution of echo speeds in all defined by Fujita, et al (1967). As the distance sectors does not show significant differences, increases, the crossing angles become larger in crossing angles of echoes in left and f ront sectors absolute value. At the same time, t he echo pattern are on the average negative. Especiall y in the changes from a stratified to a cellular appearance. left sector t he crossing angle reaches less than -20°, indicating that echoes in this sector are 5. ECHO VELOC ITIES RELATIV E TO THE HU RR ICAN E CENTER moving out from the hurricane center.

In order t o compute the relative velocities of The echo veloclty profiles are in good agree­ the radar echoes about the storm center, airborne ment with the mean echo ve locity data computed by pi ctures from Fury J were printed at 30 second in­ Senn, et al (1960a, 1960b) and 'Senn (1963) for tervals for four ten-minute segments . nine s torms, although the storm quadrants are de­ fined somewhat differently. However, our radial Th is time period was chosen so as to be less profiles of crossing angle are somewhat different than ave rage echo life time, which is on the o rde r than the nine storm average. Our data indicate a of fifteen to forty minutes , but long enough to very small crossi ng angle within 50 miles of the ass ure a reasonable degree of accuracy in deter­ storm center increasing to a maximum at a radius of mini ng the echo trajectory lengths. about 100 n. mi . The ave rage data indicate a max­ imum crossing angle at about 25 n. mi., decreasing It was necessary to take special care in t he outward. Furthermore, our data indicate that the pr inting of each picture to assure that faint re ­ region . ~f outward moving echoes is mai nly in the gions we re bu rn t in so as to be c learl y visible, left and front quadrants whereas the average data and to assure t hat t he size of each picture was indicate that this region is mainl y in the left­ i dentical. The printed pictures were then re­ rear quadrant and in both t he left-rear and left­ photographed on movie f i Im so ·that the hurricane front quadrants at small radii. center and orientation was f ixed. A loop showing slow forward echo motion and rapid backward motion Perhaps these differences can be explained, at was then constructed and projected on the Fuji t a least at radii greater than 75 n. mi., by an envi­ loop machine. Trajectories of discrete echoes ronmental flow that is different on the average in re lat ive to the s torm center were then traced and the Gulf and Atlantic Coastal areas, where the conve r ted to velocities. storms studied by Senn were located , than over the

355 •20' CROSSING ANGLE OF ECHOES

- 20'

+2

-;:••;::==:.::•:.'.::~':;·:~· ;:===::·i;= • ~f"'•-tlr-·,.:r.=1 \-.~.,;,.•.-. --:-7. INWARO + 1 ..• •.. • • ·~ .. • • • • • OUTWARO

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1: :\ Fur y F Fig. 7. The period required for an echo to com­ I.~.. ,. • IOOO ft wind . . } '"' plete a rotation around the Debbie center. The • '.: d inner eye rotates once every 1.1 to 1. 5 hours. :··~ Since these rotation periods are rather close to RE AR --::::::::::::: each other, we may approximate that the atmosphere

•00 inside the eyewall of the outer eye is in a state CENTER 100 Nouh<:ol Milts of sol id rotation . Fig. 6. The crossing angle and the relative speed of radar echoes are presented in Fig . 5. It is 6. IN- . ANO OUTFLOW FIELD AS DETERMINED BY RADAR, seen that the average echo motion is inward in the SATELLITE, AIRCRAFT AND SYNOPTIC DATA right and the rear quadrants. Echo speeds do not show appreciable variation from one quadrant to Fig . 8 shows the detailed inflow field for a the next. radius of up to 600 n. mi. from Hurricane Debbie at about 15Z on August 20 , 1969 . The cloud motions Hid-Atlantic north of Puerto Rico , where Debbie indicated are that of cumulus or towering cumulus was located. The interaction between the storm clouds and are shown to be in good agreement with circulation and the environment, would necessarily surface ship reports over the ocean and 1,000 ft . produce different resultant circulations and hence, winds over island areas. The cirrus shield over different echo trajectories in each storm quadrant . the storm precluded computing low cloud motions within 200 n. mi . of the storm center. It may be In order to determine the rate of rotation .of possible to do this in the future using the elec­ echoes around the center , the rotation period of tronic enhancing technique presently being worked each echo was computed from the angular velocity out by Fuj ita. of each individual echo. As shown in F-ig . 7, ro­ tation periods of echoes around the inner and outer In the case of Debbie good agreement was found eye walls were computed to be between 1. 1 and 1. 9 between the echo velocities and the 1,000 ft . winds hours. Since the average l ife of traceable echoes measured by Navy aircraft . Use of the echo veloci­ in the central region does not exceed twenty min­ ties then allows a complete analysis of the inflow utes, it would be very rare to find echoes making layer to be made. The double eye structure is in­ complete revolutions around the center. The ro­ dicated by the radar echoes in the figure . tation period illustrated in the figure indicates that the time required for a single echo at a given Fig. 9 shows the detailed outflow field for the distance from the center to make a complete revo­ same time period as Fig. 8. The cirrus cloud mo­ lution at its present angular velocity is that tions are supplemented by 200 mb and 300 mb radio­ indicated in the. figure. sonde data as well as 200 mb and 300 mb aircraft reports for regions outside the storm. Aga in it Fury J aircraft spent one hour 20 minutes to is difficult to compute cirrus cloud motions near complete each flight around the storm center. the storm center because the cirrus clouds are too This rotational rate of the aircraft is very close diffuse. In this region aircraft data from Fury I to that of the radar echoes around the outer eye at 31 , 000 ft . and Fury J at 39,000 ft . were used. wal l. Since both rotation ~ates are so close, a Therefore, high level aircraft flights are highly specific echo seen from the aircraft toward the valuable and necessary for a complete picture of center of the eye will appear always toward the the outflow wind field to be constructed. storm center.

356 HURRICANE DEBBIE August 20, 1969

~ V(L(IC.ITT Ol lOW tu:luOS. ~ ...... WltllOAT llOO I ., '"-" ,,_..aa .-0 AT 11001 . '"""- YlLOC•T'r OJI lCM()(t - J ~ HlltT f rU&HT 1000 f1 ....0

Fig. 8. Pattern of low-level flow around the eye of Hurricane Debbie . Five independent sources of data were used in constructing the flow pattern. They are (ll velocities of low clouds from ATS-Ill pictures betwe~n 1437 and 1623 GMT, (2) surface winds at 1200 GHT, (3) 1000-ft winds from 1200 GMT rawin observa­ tions, (4) 1000-ft Doppler winds reported by Fury F flight , and (S) ground velocit ies of echoes from Fury J fl ight around the eye between 1616 and 1712 GMT .

HURRICANE DEBBI E August 20, 1969

Fig. 9. High-level flow as determined by fi ve independent data sources.. They are (1) 39,000 ft . Doppler winds from Fury J f l ight , (2 ) 31 , 300-ft Doppl e r winds from Fury I f l ight, (3) 200 and 300 mb winds from aircraft reported between 2000 and 2100 GMT, (4 ) 200 and 300 mb rawin winds at 1200 GHT, and (5) c i rrus velocities from ATS-I II pictures between 1437 and 1623 GMT . 357 The analysis shows a region of cyclonic outflow of August 23-28, 1949, Tech. Note No . 3, M.l.T., to a radius of 150 n. mi. to the north and east, 41 pp. and 100 n. mi. to the west and south. Beyond that, an easterly jet appears to the southwest of the Mcintyre, H.D . , 1956 : Radar study of the motion storm. A sharp shear line to the east-southeast of small precipitation areas in Hurricanes Carol of the storm marks the boundary between the outflow and Edna, Cambr idge, Hass., M.l.T. Tech. Note #3 and a mesoscale further to the south. pp 30-34. Strong convergence and descend ing motion must be present here. Simpson, R.H., A.L. Sugg, and Steff, 1970: The season of 1969. Hon. Wea. ]. SUMMARY AND RECOMMENDATIONS ~. 98, 293-306. Airborne radar and ATS-I II satellite pictures Senn, H.V., 1960a : The mean motion of radar echoes have been used together with aircraft and synoptic in the complete hurricane, Proc. 8th Wea. Rad. wind data to produce a complete and detailed anal­ Conf. Apri 1 11-14, 1960, 427-434. ysis of the inflow and outflow fields in Hurricane Debbie on August 20, 1969. Radar echo velocities Senn, H.V., H.W. Hiser and R. D. Nelson, 1960b: have been computed using Fujita's time-lapse film­ Studies of the evolution and motion of radar loop technique and radial profiles constructed for echoes from hurricanes , Final Report, U.S. four quadrants of the storm. Their spatial distri­ Weather Bureau, Rept. No. 8944-1, August, 1960. bution has been plotted and used as an indication of the low level flow field within 150 n. mi . of Senn, H. V., 1963 : Radar precipitation echo motion the storm center. Low cloud velocities have been in Hurricane Donna, Proc. 3rd Tech . Conf . on computed using ATS-I II film loops and compared with Hurr. and Trop. Meteor., June 6-12, 1963. ship reports. Watanabe, K., 1963 : Vertical wind distribution The outflow field was constructed using high and weather echo (in the case of the typhoon), level aircraft wind data and cirrus cloud motions Proc. Tenth Wea. Rad. Conf., April 22-25, 1963, computed from ATS-I II film loops. 222-225. In the future, it is hoped to be able to com­ pute echo ve locities at several different times for the purpose of determining the change with time of the echo velocity profiles for the various quad­ rants of the storm. It is suggest~d that this would be a more meaningful evaluation of the effects of hurricane seeding on the storm as a whole than aircraft wind profiles at one level . In addition, by evaluating changes in the inflow and outflow fields hour by hour, made possible with the use of echo and cloud velocities, a more complete evalua­ tion of the effects of seeding on storm structure could be made. Changes in low level convergence and high level divergence could be calculated as wel l as changes in storm kinetic energy and angu­ lar momentum. ACKNOW LEDGEMENTS

The research performed at the University of Ch i cago was sponsored by ESSA under grant E-22-69- ]0{G) and NASA under NGR-14-001-008. REFERENCES

Fujita, T., 1959: A computation method of veloc­ ity of individual echoes inside hurri canes. Final Report Cwb 9530 pp.].

Fuji ta, T. T., lzawa, K. Watanabe, and I. Imai, 1967 : A model of accompan ied by inner and outer rainban ds. J. of App . Meteor. ~. 3-19. Gentry, R.C . , 1970: Hurri cane Debbie Modification Experiments, August, 1968. Science, .!§.!!_, 473- 475. Jordan, C. L. , 1960: Spawinds for the eye wall of Hurricane Daisy of 1958, Proceedings of the Eighth Weather Radar Conference, April 11-14, 1960, 219-226.

Ligda, M.G.H., 1955 : Analysis of motion of small precipitation areas and bands in the hurricane

358 MESOMETEOROLOGY PROJECT - - - RESEARCH PAPERS (Continued from front cover) 42. .A Study of Factors Contributing to Dissipation of Energy in a Developing Cumulonimbus - Rodger A. Brown and Tetsuya Fujita 43. A Program for Com put er Gridding of Satellite Photographs for Mesoscale Research - William D. Bonner 44. Comparison of Grassland Surface Temperatures Measured by TIROS VII and Airborne Radiometers under Clear Sky and Cirriform Cloud Conditions - Ronald M. Reap 45. Death Valley Temperature Analysis Utilizing Nim bus I Infrared Data and Ground-Based Measurements - Ronald M. Reap and Tets uya Fujita 46. On the "Thunderstorm- High Controversy" - Rodger A. Brown 47. Application of Precise Fujita Method on Nimbus I Photo Gridding - Lt. Cmd. Ruben Nasta 48. A Proposed Method of Estimating Cloud- top Temperature, Cloud Cover, and Emissivity and Whiteness of Clouds from Short- and Long- wave Radiation Data Obtained by TIROS Scanning Radiometers -T. Fujita and H. Grandoso 49. Aerial Survey of the Palm Sunday Tornadoes of April 11, 1965 -Tetsuya Fujita 50. Early Stage of Tornado Development as Revealed by Satellite Photographs - Tetsuya Fujita 51. Features and Motions of Radar Echoes on Palm Sunday, 1965 - D. L. Bradbury and T. Fujita 52. Stability and Differential Advection Associated with Tornado Development - Tetsuya Fujita and Dorothy L. Bradbury 53. Estimated Wind Speeds of the Palm Sunday Tornadoes - Tetsuya Fujita 54. On the Determination of Exchange Coefficients: Part ll - Rotating and Nonrotating Convective Currents - Rodger A. Brown 55. Satellite Meteorological Study of Evaporation and Cloud Formation over the Western Pacific under the Influence of the Winter Monsoon - K. Tsuchiya and T. Fujita 56. A Proposed Mechanis m of Snowstorm Mesojet over Japan under the Influence of the Winter Monsoon - T. Fujita and K. Tsuchiya 57. Some Effects of. Lake Michigan upon Squall Lines and Summertime Convection - Walter A. Lyons 58. Angular Dependence of Reflection from Stratiform Clouds as Measured by TIROS IV Scanning Radiometers - A. Rabbe 59. Use of Wet-beam Doppler Winds in the Determination of the Vertical Velocity of Raindrops inside Hurricane Rainbands - T. Fujita, P. Black and A. Loesch 60. A Model of Typhoons Accompanied by Inner and Outer Rainbands - Tetsuya Fujita, Tatsuo lzawa., Kazuo Watanabe and Ichi ro Imai 61. Three-Dimensional Growth Characteristics of an Orographic Thunder storm System • Rodger A. Brown 62. Split of a Thunderstorm into Anticyclonic and Cyclonic Storms and their Motion as Dete rmined from Numerical Model Experiments Tetsuya Fujita and Hector Grandoso 63. Preliminary Investigation of Periphera l Subsidence Associated with Hurricane Outflow - Ronald M. Reap 64. The Time Olange of Cloud Features in , 1961 , from the Easterly Wave Stage to Hurricane Dissipation - James E. Arnold 65. Easterly Wave Activity over Africa and in the Atlantic with a Note on the lntertropical Convergence Zone during Early July 1961 - James E. Arnold 66. Mesoscale Motions in Oceanic Stratus as Revealed by Satellite Data - Walter A. Lyons and Tetsuya Fujita 67. Mesoscale Aspects of Orographic Influences on Flow and Precipitation Patterns • Tetsuya Fujita 68. A Mesometeorological Study of a Subtropical ·Hidetoshi Arakawa, Kazuo Watanabe, Kiyoshi Tsuchiya and Tetsuya Fujita 69. Estimation of Tornado Wind Speed from Characteristic Ground Marks - Tetsuya Fujita, Dorothy L. Bradbury and Peter G. Black 70. Computation of Height and Velocity of Clouds from Dual, Whole-Sky, Time· Lapse Picture Sequences • Dorothy L. Bradbury and Tetsuya Fujita 71. A Study of Mesoscale Cloud Motions Computed from ATS-I and Terrestrial Photographs • Tetsuya Fujita, Dorothy L. Bradbury, Clifford Murino and Louis Hull 72. Aerial Measurement of Radiation Temperatures over Mt. Fuji and Tokyo Areas and Their Applicati on to the Determination of Ground­ and Water-Surface Temperatures - Tetsuya Fujita, Gisela Baralt and Kiyoshi Tsuchiya 73. Angular Dependence of Reflected Solar Radiation from Sahara Measured by TIROS VII in a Torquing Maneuver • Rene Mendez. 74. The Control of Summertime Cumuli and Thunderstorms by Lake Michigan During Non-Lake Breeze Conditions • Walter A. Lyons and John W. Wilson 75. Heavy Snow in the =.:hicago Area as Revealed by Satellite Pictures • James Bunting and Donna Lamb 76. A Model of Typhoons with Outflow and Subsidence Layers - Tatsuo lzawa

• out of print (continued on outside back cover) SATELLITE AND MESOMETEOROLOGY RESEARCH PROJECT --- PAPERS (Continued from inside back cover)

77. Yaw Corrections for Accurate Gridding of Nimbus HRIR Data - Roland A. Ma,dden 78. Formation and Structure of Equatorial Caused by Large-Scale Cross Equatorial Flows Determined by ATS I Photographs - Tetsuya T . Fujita and Kazuo Watanabe and Tatsuo Izawa · 79. Determination of Mass Outflow from a Thunderstorm Complex Using ATS III Pictures - T. T. Fujita and D. L. Bradbury 80. Development of a Dry Line as Shown by ATS Cloud Photography and Verified by Radar and Conventional Aerological Data - Dorothy L. Bradbury 81. Dynamical Analysis of Outflow from Tornado-Producing Thunderstorms as Revealed by ATS III Pictures - K. Ninomiya 82. Computation of Cloud Heights From Shadow Positions through Single Image Photogrammetry of Apollo Pictures - T. T. Fujita 83. Aircraft, Spacecraft, Satellite and Radar Observations of Hurricane Gladys, 1968- R. Cecil Gentry,- Tetsuya T . Fujita and Robert C. Sheets 84. Basic Problems on Cloud Identification Related to the Design of SMS-GOES Spin Scan Radiometers - Tetsuya Theodore Fujita 85. Mesoscale Modification of Synoptic Situations over the Area of Thunderstorms' Development as Revealed by ATS III and Aerological Data - K. Ninomiya

86. Palm Sunday Tornadoes of April 11, 1965 - T. T. Fujita, Dorothy L. Bradbury, and C. F. Van Thullenar. (Reprint from Mon. Wea. Rev., 98, 29-69, 1970) 87. Patterns of Equivalent Blackbody Temperature and Reflectance of Model Clouds Computed by Changing Radiometer' s Field of View - Jaime J. Tecson

88. Lubbock Tornadoes of 11 May 1970 - Tetsuya Theodore Fujita

89. Estimate of Areal Probability of Tornadoes from Inflationary Reporting of Their Frequencies - Tetsuya T. Fujita

90. Application of ATS III Photographs for Determination of Dust and Cloud Velocities Over Northern Tropical Atlantic - Tetsuya T. Fujita

91. A Proposed Characterization of Tornadoes and Hurricanes by Area and Intensity - Tetsuya T . Fujita

92. Estimate of Maximum Wind Speeds of Tornadoes in Three Northwestern States - T. Theodore Fujita