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This is the first report of the study prepared to provide generalized typhoon specificationsthat are consistent geographically and meteorologically for use in planning, evaluating andestablishing typhoon design criteria for typhoon protection works. The Standard ProjectTyphoon, which is an~ilogous to the Standard Project Hurricane in the United States, isdefined and its indices are derived based on analysis of past typhoons in this first report.

The Second Miyako Jima Typhoon (the typhoon 6618) struck Okinawa area inSeptember, 1966 with a force as severe as never experienced and took the worst courseto Miyakojima islands. The structural damage caused by this typhoon was also theseverest one. Although the most houses destroyed were wooden structures, the rateof damaged houses was around 50%. This is the report on that damage investigatedan Miyakojima and Ishigakijima directly after the typhoon.

Natural wind is not an uniform flow of air and the wind pressure against a structureis different partially at the same moment. The strong wind pressure distributions andvariations are discussed on some records of typhoons.

The problem of finding the length and the duration of a peak gust seems to be importantfor the wind-proof design of structures. It is assumed here that the scale of peak gust isequal to its wind run, and the relation between the scale of peak gust and the maximumwind speed is derived from the experimental relation between the gust factor and the gustduration time, which was obtained by one of the authors before. From the result, we proposethe design wind speeds corresponding to the sizes of structures.

In this paper, the outlines of the analog data analyser system to estimate mean value andstandard deviations of wind speed and wind direction measured by a two dimentional sonic ane-mometer are described. The results obtained by this analog system agree well with those by ausual digital method for mean value and standard deviation of wind speed and mean of winddirection within relative error of 5%, and for standard deviation of wind direction within 20%.

Wave forecasting is one of the most important problems in coastal engineering at present.The problem of forecasting storm waves in deep water is, however, somewhat handicappedby lack of adequate data for storm winds and waves and by lag of the development of mechan-ical procedures of forecasting for moving fetches and variable wind vectors.In this paper, the graphical approach by Wilson in 1955 for moving fetches and variablewind vectors is discusse~l, and a modified new graphical approach is proposed.Both approaches are applied to the analysis of deep-water wind waves generated by Ise-Bay Typhoon.

Severe wind storm caused by the Second Miyakojima Typhoon (6618 Coins) overSakijima Islands, Okinawa is studied in this paper after the results of the expedition tothis area. The maximum wind speed of 60.8 in/s and maximum peak gust of 85.3 in/swere observed at Miyakojima IsI. Wind was so strong because the typhoon passed justnear the island and the maximum wind zone passed over it and strong wind lasted solong because the movement of the typhoon was as slow as 10km/b. During thepassage of the typhoon quite clear periodical changes of weather parameter such asatmospheric pressure, wind, rainfall and so on are seen at Miyakojima Isl. The periodof them was about 50 minutes.

Rainfall on the wall of the building in the storm is studied. Rain water on the wall is forcedinto the inside room by wind pressure and causes disaster. Observation on the real buiding wallwas made for about one year. The results show that the ratio of rainfall on the wall to the horizontalrasnfall increases with wind velocity component normal to the wall. The proportional constantis nearly equal to the converse of the mean fall velocity of rain droplets.

1964年9月24日から25日にかけて日本西部を通過した台風20号Wildaは上陸時の中心気圧約940mbで, 日本全体として見ても平均10年に一度ぐらいの割合でしか襲って来ないような比較的強いものであった。この台風の通過に伴って各地では強い風が吹いたが, 中でも四国の宇和島では最大瞬間風速72m/secという大きな値が記録された。一方このような台風の強さや大きな風速の割には被害が少なかった。これら2つの事柄はこの台風の特色として注目すべきことである。著者らは台風の通過後直ちにこの台風の調査に着手し, 代表的な例として台風の一般的性質を調べると同時に上に述べた特色について特に重点をおいて考察を進めた。この台風は九州から斜めに四国と中国を横断して行ったので, 陸上を通過した距離が比較的長く, 地上観測の結果に基づいて解析を行ない得る時間が長いこと, またこの台風が特に顕著な前線を伴わなかったことはともにこの台風を日本を襲う台風の代表的なものとして解析を行なうことの意味を認めさせる事柄であった。以下はその解析の結果である。, Wind storm caused by Typhoon Wilds (6420) which passed over Japan on 24 and 25 Sept.1964 is studied. The typhoon central pressure on the coast of Kyusbu was about 940 mb.The observed maximum wind speed distribution is analysed in comparison with the computedmaximum gradient wind speed distribution and with the distribution of wind disasters. Theexistence of a small disturbance in the typhoon is proposed as the explanation of the extraordin-ary large peak gust speed of 72 in/sec observed at Uwajima.

本研究の目的は雨滴あるいは海面より舞上った水滴が空中に混在している場合・暴風の機械的破壊作用がそれを含まない場合に比して増大するかどうかということを再検討することにある。暴風雨の中に立てば顔に当る雨滴は我々に痛みを感ぜしめるし, また窓ガラスを打つ雨滴は非常に激しい音を立てる。しかし, その強さが我々が構造物を設計したりする時に考慮しなければならないほどの破壊作用を有するものかどうかということについてはあまり詳しく調べてられいなかったのが実情である。, The effects of rain or Water drops on storm damages are studied. The increase ofmean air density from rain water contained in the air is negligibly small and wind forceexerted on the structure does not increase even in heavy rain. However, the momentumof each droplet is estimated to be large enough to destroy a small part of structures, such as coating surface.

Three dimensional wind components at 1Gm from the ground in typhoon winds are studiedby the use of a propeller anemometer and the new all-weather type bivane, whose free periodis about 15/V sec and damping ratio is 0.15, at Shionomisaki Wind Observatory of Kyoto Univ.The data used in this study was odtained on Aug. 2~, 1963 when typhoon 6311 was passingover the southern ocean of Shionomisaki. The mean wind speed over the sampling duration(6 mm) was 18.3 in/sec. The vertical fluctuating components are smaller than longitudinal ones, and decrease more rapidly with averaging time than those. The ratio is about 20-'3l~%for a few seconds averaged wind speed, but it becomes nearly 10% for 20 or 30sec. Andthe correlation coefficient between longitudinal and vertical components is about 07.

The author reported the outline features of the coastal disasters hy the Ise-baytyphoon, which attacked on the 26th of September in 1959, at the annual meeting ofour Institute, Kyoto University.At this meeting, the author explained mainly the destruction phenomena of thecoastal structures by the colour film. Afterwards, the author has investigatedsome other problems, I.e. the properties of the flood waves travelling up the riverand the phenomena of the abnormal high water in this bay. So, the author presentssome opinions about the reconstruction planning and points several important andnecessary subjects to be studied, experienced by this typhoon.

It is well known that the correction factor "n" must be inevitably used in estimating a fre-quency spectrum of surface wave pattern from a record of pressure-type wave gauge. Therefore, frequency spectrum of this factor, which has not been understood well, is studied by analysingsome simultaneous observation records of capasitance-type and pressure-type wave gauges atthe Shirahama Oceanographic Tower Station in Tanabe Bay. Values of this factor "n" obtainedfrom the cross spectrum analysis are 1.13 at 0.1 c/s, 1.39 at 0.3 c/s, and 1.60 at 0.5 c/s and agreewell with Seiwell's and Folsom's observed results. Corrected power spectra obtained from under-water pressure records at the Tower Station using our present correction factor "n" show an equi-librium range of wind wave spectrum characterized byf-5 law.

Turbulent structure of storm gusts in the typhoon was studied using several high responseanemometers set on the masts which are on the line perpendicular to the wind direction. The resultshows that correlations of wind pressure fluctuations decrease rapidly with distance.

台風7220は1972年9月16目夕方, 和歌山県串本町潮岬西方に上陸し, 紀伊半島を通り抜けた。この時, 潮岬においては, はっきりした台風眼通過現象が見られた。この際, 京大防災研究所潮岬風力実験所で台風眼通過時前後の風速の早送り記録を得ることができたので, これを解析し, 台風中心附近の風の特性を調べてみた。この解析においては台風のeyewaHの近くの最大風速域の通過前後の強風の盤質と共に従来調べられたことのない台風眼内の風の性質についても調べることができた。, Characteristics of wind speed fluctuation of Typhoon 7220 were analyzed using the windspeed records at Shionomisaki where the typhoon eye passed. Characteristics of wind turbulenceat high wind speed before and after the pass of the typhoon eye resemble each other and spectralpeak is found at about 300 m in the wave length. Near the center of the typhoon eye, wind speedis as low as 10 m/s. However the intensity of turbulence and spectral peak wave length are almostthe same as those in the high wind cases.

Maximum wind speed distribution of Typhoon 7010, which passed over theJapanese Islands inthe morning of Aug. 21, 1970, was analyzed using the wind records and the results of the winddisaster survey. The central pressure of the typhoon at the time of landing was about 960 mb, that is as low as the value corresponding to the occurrence probability of 1/5 per year. The radiousof the maximum wind zone was about 60 km and which is nearly equal to the radius of the eyewall observed by the radar.

Observations of the horizontal distribution of the number concentration of giant sea-saltparticles near the ground surface were carried out in the strong wind conditions at several stationslocated from the coast to the inland near Ogata, Niigata Prefecture, on Jan. 24, Dec. 13, and Dec.14, 1970.The wind from the sea ranged from 10 to 18 m/sec in speed in the lowest several hundredmeters layer. The observation showed that the particle number concentration near the grounddecreased with distance from the coast, as expected from our theory.The impaction-sedimentation ratio, γ, estimated from our present observation, is about 10 forthe wind of 10 m/sec, and about 13 for 16 m/sec.However, the impaction factor, λ, obtained from our observation, is rather smaller than butnearly the same order with that written in the previous report on the observations of the horizontaland vertical distributions for the weak wind.The particle number concentration observed at the coast is compared with data observed byToba et al. at the sea surface. The concentration at the coast for the variable wind speed is alsodiscussed.

Tatsumaki, thunderstorm and small whirl wind are known as local severe storm in Japan.They occur very rarely and their scale is smaller and the amount of money of damage is lessexpensive than typhoons'. But sometimes they cause severe damage to structures. We must takethe wind effects of such local severe storms into consideration in the design of wind resistantstructures. We have not sufficient knowledge about them. Only way to understand them is toexplore and analyze the damages. We had the chance to explore the damage of severe storm atHikone City and here report it.

In the evening of Dec. 7 th, 1969 a Tatsumaki caused severe damage in the city of Toyohashi, situated on the coast of Ise Bay in the central part of the Japanese main island. About 70 personswere killed or wounded, more than 100 houses were damaged. Moreover, the Tokaido and NewTokaido Lines of JNR and highway Route 1 connecting Tokyo and Osaka were stopped for a longtime, and therefore indirect social damage extended throughout in the main part of Japan. Theauthors have surveyed the characteristics of the Tatsumaki and the damage to structures and re-ported the results in this paper. The characteristics of this Tataumaki obtained by the survey maybe considered to be a first approximation of Japanese Tatsumakis to be applied to the design ofwind resistant structures.

The damage distributions of houses by the typhoon of September, 1951, or theSecond Muroto Typhoon, were explored to study the relations between the local damagerates and the maximum wind velocities, comparing with the case of Isewan Typhoon in1959, that was reported before. Also the influence of site to the damage is discussed.

The small scale disturbances, which meight cause strong winds and wind disasters, are studied. Tatsumaki is the small scale weather phenomenon which causes most severewind in Japan. Statistical features of Tatsumakis, which were observed during pastten years are studied and compared with tornadoes in the United States.

A power-spectrum analysis of horizontal wind speed is made over a wide range fromabout 107 cps to 2. 5 x 10-1 cps by piecing together various portions of the spectrum.There appear to be three major eddy energy peaks in the spectrum; one peak occurs ata period of 4 days, second peak occurs at a period about 1 day and the third one occursnear a period of 1 mm.Between the later two peaks, there is a broad spectral gap. The power spectraldensity decreases in proportion to the -5/3th power of frequency between 10-5 cps (theperiod is about 1 day) and 10-4 cps (the period is about 3 hours) as well as in the fre-quency range higher than 10-1 cps.

The characteristics of typhoon 7123 (Trix) were analysed in her decaying stage during thepassage over the Japan Islands from 30th to 31st of August 1971. The velocity of the typhoonmovement was nearly consistent with that of the upper current at 500 mb or 700 mb level. Detail-ed analysis shows that, when the typhoon center was over land, the typhoon was filling morerapidly and moved more slowly than the case over the sea. When the typhoon was passingover the mountain range, the isobaric pattern of the central part was deformed.

The role of warm anticyclone over Tibetan Plateau in the outbreak and maintainanceof the summer monsoon of Southeast Asia is outlined and, taking annual rainfall at PhoomPenh in Cambodia as an indicater of the summer monsoon, the close correlation of I.ts secularvariation and that of general circulation is revealed, specially in connection with solar activityof double sunspot period. It is suggested that the variations of double sunspot period and relatedperiods in the general circulation are effected through the warm anticyclone over Tibetan Plateau-a suggestion which leads to the possibility of the artificial control of climate in future.

Typhoon Nancy (6118) called Second Muroto Typhoon passed over the Japan Islands, remaining remarkable records of high wind and low pressure on Sept. 16, 1961. First, the positions of the typhoon center after its landing are studied from several points ofview. Definitions of the typhoon center employed in this study are 1) the geometricalcenter of the pressure distribution, 2) the center determined by the minimum pressuredistribution and its occurrence time, 3) the geometrical center of the wind system and4) the geometrical center of the rader echo. The results determined by available datacoincide each other within their ranges of error in determination which are fairly large.Second, distribution of maximum wind speed is studied. The axis of maximum wind zoneruns about 20 km east of the path of the typhoon center. And the other characteristicfeature of the high wind distribution of this typhoon is existence of anothor high windzone along the cost line of Japan Sea, which is caused by the cold front stimulated bytyphoon movement. Lastly, topographic effect on high wind is studied by use of theelectric power line damage distribution.

In many developed countries there has been remarkable increase in the numbers of people who arethreatened each year by typhoons and hurricanes. This is not because of population growth so much asthe increasing affluence which allows people to relocate in warm coastal areas where they can take advantageof a warmer climate and greater recreational opportunities throughout the year. This poses many chal-lenging problems in limiting the potential for disaster from severe coastal storms, especially from typhoonsor hurricanes. With the increasing congestion of property and lives-at-risk when a typhoon strikes, the system and procedures for protection of property and safe-guarding lives which served well in the pastmay fail in the future. It is therefore necessary to examine the options within reach to resolve these prob-lems. In the United States there has been many efforts to define and evaluate various options including (1)improving the timeliness of warnings: (2) more exact predictions of the character and scope of coastalplain flooding from storms surges: (3) better public communication of the growth hour-by-hour of risksfrom an approaching hurricane: (4) a means of reducing the number of people who must be evacuatedinland to safe shelters: and (5) the engineering design of structures resistant to high winds and stormsurges. We shall discuss some of the findings, but first lets examine briefly the factors which are complicat-ing the warning and preparedness programs as they currently exist.