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Storm runoff and sediment discharge during the typhoon 200514 (Nabi) weremonitored in three forested basins (WS1: 6.6 ha, WS2: 9.2 ha, WS3: 8.2 ha) at theSarukawa Experimental Watershed located in Mivazaki Prefecture, southwesternJapan. Dormant geology in the area is chaotic beds of mudstone and sandstone withinthe Shimanto Belt (an accretionary prism). The total amount of precipitationassociated with the typhoon storm event was 1,156 mm. Although the maximum 1-hrprecipitation was 40.5 mm/hr and not exceptionally higher than average annual record, high and intense rainfall (precipitation >23 mm/hr) continued 19 hours.During the storm event, the greatest peak and total catchment runoff was observedin WS1 and WS3 and direct storm runoff coefficient became 83 and 98% respectively.Sediment discharge volumes measured by deposits behind weir ponds of WS1, WS2and WS3 were 2.5, 7.3 and 1.9 m3/ha, respectively. Several slope failures occurredon hillslopes and zero-order hollows in WS2. Hence, the greatest sediment dischargeobserved at the weir of WS2 potentially associated with remobilization of depositedmaterial within the channels and riparian zones, because most of sediment due toslope failures deposited on the foot of hillslopes. Continuous monitoring of runoff andsediment discharge will help to understand the spatial and temporal variations ofsediment supplied, deposit and transport in forested watersheds.

台風0418号が通過した際に，厳島神社周辺では地形性の強風が発生し各種被害が起きた。また，過去にも同じようなコースを台風が進むときに，同様な被害を受けたことが報告されている。本報では，このような地形性の強風の実態を解明するために，数値シミュレーションにより台風通過時の厳島神社周辺における強風場を再現した。その際，メソスケールの気象場を解析できるPSU/NCAR MM5，および，LESを用いた狭域スケールの非定常・非線形風況シミュレータRIAM-COMPACTを用いた。計算結果は実測値や被害の調査結果と比較し，精度や境界条件の与え方等，計算を行う際の問題点について検討を行った。また，計算結果から求めた最大風速分布は，建物や人的被害の分布と良く対応しており，強風被害予測の可能性を示した。, The strong wind fields around Miyajima in Hiroshima Bay were simulated numerically during Typhoon Songda in 2004. The PSU/MM5 model was used for the calculation of meso-scale regions. The strong wind that passed over the sea and blew into the Hiroshima Bay was simulated. The predicted wind fields were examined comparing with the observed records and the field investigation of damage to the human and buildings. The calculated maximum wind speed map was well correlated to the distribution of damage rate by strong wind in Hiroshima Prefecture. Unsteady wind fields were also computed by Large Eddy Simulation in the fine region around Miyajima. The local wind characteristics caused by the topography around Itsukushima Shrine were investigated. The down flow along the valley to the south of the shrine was simulated in the neutral atmospheric condition. The local wind flows around the shrine were discussed.

2004年（平成16年）10月20日に，大阪市付近に上陸した台風23号により由良川沿川の四市一町（福知山市・舞鶴市・綾部市・宮津市・大江町）は，浸水家屋約1700戸，浸水面積2600haに達する大きな被害を受けた。この台風23号は福知山上流域で流域平均2日雨量276mmの降雨をもたらし，福知山水位観測所では，昭和28年に福知山市内で浸水家屋数約3800戸に達する大災害をもたらした台風13号に次ぐ水位が観測された。本研究では，こうした大規模洪水が物理的な背景にもとづいた分布型降雨流出モデルで適切に再現できるかを検討している。ここではまず2004年洪水を分布型流出モデルにより再現した。次に，2004年洪水を再現可能なモデルが過去の小中規模洪水を適切に再現するかを検討した。その結果、同じモデルパラメータの値を用いて，同地域においては中小洪水から計画規模に匹敵するような大洪水まで概ね良好に再現できることがわかった。, This paper analyzes the Yuragawa river flood by Typhoon No.23 on 19-22 October 2004 which brought the large number of casualties and loss of asset especially at the downstream region of the Yuragawa catchment. First, the discharge-hydrograph at Fukuchiyama during the flood is reproduced by a distributed rainfall-runoff model. The simulated discharge-hydrograph after the parameter adjustment shows a good fit with the observed discharge-hydrograph. Afterwards, the model with the same parameter is applied to two past-medium-size floods, which also exhibit the good performance of the model. From these applications, it is clarified that the physically-based distributed rainfall-runoff model has a high potential to reproduce floods of any size in the catchment.

2004年には観測史上最多の10個の台風がわが国に上陸し，各地で多大な被害をもたらした。2004年6月21日には，西日本に襲来した台風0406号の強風により滋賀県近江八幡市でホテルの屋根が飛散し，新幹線の架線に掛かって7時間にわたって新幹線の運行を停止する事故が発生した。飛散した屋根の重量は7 トンもあり，甚大な二次災害を発生させる恐れもあった。本稿は，現地調査結果に基づいてこの被害の原因について述べたものである。, Typhoon 0406 attacked Kinki area, Japan, in June 21, 2004. A covered metal roof on a hotel was blown off from the roof by severe wind, and flew to neighboring JR Shinkansen railway track. The roof had the size of 9m by 41m and the weight of 7 ton. JR Shinkansen railway service was suspended during 7 hours. The scattering wind is estimated about 13.5m/s to 20m/s that is less than the design wind speed.

平成16 年7 月25 日に発生した台風10 号に伴って, 徳島県南部地域では7 月30 日から8 月2 日までの4日間で連続降雨量が2, 000mm を超過する記録的な豪雨が発生した。この豪雨により，徳島県木沢村の大用知, 加州, 阿津江及び釜ケ谷地区で大規模な斜面崩壊が発生した。現地調査, 計測を行った結果, これらの斜面崩壊が高速長距離運動となったと考えられる。また, 阿津江地区の崩壊により崩壊地の背後に再滑動を始めた大規模な地すべりが生じたことが判明された。さらに, リングせん断試験機を用い, 阿津江と釜ケ谷崩壊地から採取した試料に対して降雨による斜面崩壊の再現実験を実施した。その結果, 地下水位が降雨により一定の値まで上昇することによって, 崩壊が発生し, その後せん断に伴って水圧が急速に増加し, せん断抵抗が低い値まで低下したことが分かった。, During Typhoon Namtheun, heavy rainstorm fell on Shikoku area, and triggered numerous landslides in Nakagawa basin of Tokushima Prefecture, Japan in August 1, 2004. Among them four large landslides were triggered in Kisawa village, causing great damage to properties and leading the missing of two persons. Preliminary investigation on them revealed that these landslides experienced rapid long runout movement. Ring shear tests on the samples from different landslides showed that shear resistance could be reduced greatly due to the build-up of high excess pore-water pressure after the shear failure was triggered by the increase in ground water table during the rain.

2004年は合計10個の台風が日本に上陸し，全国各地に甚大な被害をもたらした．その10個目の台風となった23号（TOKAGE）の接近，および活動を活発化させた前線の影響を受けて，由良川流域では流域平均雨量が274mmに達する大雨となり，福知山盆地および下流域において浸水被害が発生した．本報は，災害発生直後より行われた現地調査・資料収集の結果を取りまとめたものである．今回の洪水は，昭和28年台風13号による洪水に次ぐ規模のものであり，過去の水害を凌ぐ急激な水位上昇を伴ったことが確認された。, In October, 2004, heavy rainfall occurred in the western part of Japan by Typhoon 0423(TOKAGE), which was a record 10th typhoon to hit Japan in 2004, and it caused enormous flood damage. This paper describes the outline of flood disaster in the Yura River basin based on field survey. The Yura River basin is prone to suffer flood damage. The flood in 2004 had the second-highest scale in the past several decades and brought serious flooding in the basin. Further， record water level rising was observed in several points along the Yura River.

2004年9月7日に広島県の厳島神社を襲った台風18号による被害について，現地調査を行い，厳島神社および周辺の被害や強風に関する各種データを集めた．それらの資料をもとに，当時の気象状況および被害の実態について明らかにした．厳島神社では本社拝殿，西回廊，客神社祓殿などの檜皮屋根のめくれ，能舞台の軒瓦の飛散などが強風による被害であった．また，回廊や平舞台，高舞台，火焼前，左楽房などが高潮と波によって被害を受けた．さらに，神社南側に延びる谷筋に沿って吹き降りる強風が被害状況や目撃証言などにより確認された．, Typhoon 0418 struck Miyajima Island, in the prefecture of Hiroshima, Japan, on September 7, 2004. There was a maximum peak gust of 60.2m/s which was the strongest wind ever recorded by theHiroshima Local Meteorological Observatory. Itsukushima Shrine, a designated world heritage site onMiyajima Island, suffered various kinds of damage. We conducted a field investigation immediatelyfollowing the typhoon. The wind environment and the damage to the shrine as well as to the surroundingarea were investigated and will be described in this report.

南アジアにおいて発生する竜巻等の突発的メソ気象擾乱発生に関わる環境場の特徴について調べた。これら突発的なメソ気象擾乱の多くをもたらすとされる組織化した積乱雲（マルチセルやスーパーセル）の発生と発達に重要な大気の熱的安定度と風の鉛直シアーに注目し，これらをパラメーター化して定量的に評価し，その時間的・空間的分布を調べた。その結果，プレモンスーン期バングラデシュ付近で熱的不安定度と風の鉛直シアーが共に顕著に増大することが示され，積乱雲が組織化してより発達したものになりやすい環境場であることが示された。, The environmental characteristics related to the outbreak of meso-scale meteorological disturbances such as tornado are investigated. The thermodynamic instability and vertical shear which are important for the occurrence of an organized cumulonimbus cloud (multicell and supercell) that often causes sever meso-scale disturbances are noticed and the spatial and temporal distribution of them in the South Asia is quantitatively investigated. It is shown that the thermodynamic instability and vertical shear are considerably increasing in and around Bangladesh during the pre-monsoon season. This indicates that the organized cumulonimbus cloud tends to occur in and around Bangladesh during pre-monsoon season. This result is consistent with the climatological fact that severe meso-scale disturbances (tornado, hail, gust and so on) concentrate in Bangladesh and adjoining north east India.

台風通過時の気圧データには, しばしば台風の中心とは異なる場所で気圧が急低下するPressure dipが観測される。この現象の研究例は, 過去にいくつかの事例解析があるもののその発生や維持メカニズムは未だ解明されていない。著者らは過去に日本に上陸, 接近した台風についてPressure dipを検出し, 多くのPressure dipを解析して普遍的な性質を見出した。そしてその性質から, Pressure dipが内部重力波が伝播したために地上で発生した現象であるという考察を示唆した。, A Pressure dip is small pressure depression, often observed as a meso-scale phenomenon in a typhoon internal system.Its mechanism and the details of structure have not been clarified at present.In this paper, the several Pressure dips are detected and investigate to draw its general view.We tried to explain the Pressure dips in the point of the propagation of the internal gravity wave.

1999年9月24日に九州地方を縦断した台風9918号は, 熊本県鹿島村で最大瞬間風速83m/sを記録するなど, 各地で記録を更新する強風が吹き, 八代海沿岸地域で高潮による死者12人を含む甚大な人的・建物・鉄塔・農林被害をもたらした, 本報では現地調査および航空機による空からの被害調査を行い, 建物の被害状況や航空機からの映像によるシート率の分布を求め, 建物被害率との関係を検討した, また, 建物被害率と気圧場から推定した風速との関係も求めた., The damage of buildings and houses by Typhoon 9918 along Yatsusiro Sea was studied. The damage rate of buildings and houses was obtained.The sheet rate was also calculated by the aerial photos. The relation of these values was examined.The relation between the damage rate and the maximum gust wind speed was also evaluated.

1999年9月24日に九州を襲った台風9918号は, 海面水温28℃以上の高水温域を通過してきたこともあり, 最盛期の強い勢力を維持して熊本県北部に上陸した。このため, 熊本県不知火町松合地区で高潮が発生し, 12名の死者を出すなど強風により大きい被害を残した。そこで, この台風について, 気圧場の客観解析を行って, 気圧分布の特徴について検討した。また, 気圧分布から傾度風風速を計算し, 海上風風速を推算した。その結果, 海上風の最大風速半径は40㎞程度と小さく, このため八代海が最大風速域に当たり, !時間以上にわたって30ms‐1を超える強風が吹いていたと考えられる。一方, 台風9918号とほぼ同じコースを通過して上陸した台風9612号の解析結果によると, 最大風速半径が100㎞を超え, 八代海では強い風が吹いていなかった。このことは, 台風による強風災害においては, コースや最大風速だけでなく, 最大風速半径も重要塗要素であることを意味している。, Typhoon 9918 (Bart) hitting the Kyushu District on Sept. 24 in 1999 with veiy strong intensity caused storm surge at Matsuai-area of Shiranui in Kumamoto Prefecture and 12 people died. We analyzed the pressure pattern by the objective method and estimated the sea surface wind from the gradient wind. The estimated wind distribution indicates that the strong wind exceeding 30 m s-1 occurred over one hour in the Yatsushiro Sea.Typhoon 9612 (Kirk) made landfall after passing a similar course as Typhoon 9918 on Aug.14 in 1996, but the estimated sea surface wind in the Yatsushiro Sea is 20 m s-1 or so. This relatively weakwind may have its cause in the large eye exceeding 100 km in diameter. The analyzed result indicates that radius of the maximum wind speed is an important parameter in wind disaster occurrence by a severe typhoon.

[ABSTRACT] In remote sensing, the correction of satellite data for atmospheric turbulence is an important problem. In this paper, the degrees of spatial coherence of the light that has passed in an atmospheric turbulence chamber are measured. Water vapor are selected as a factors of turbulence. Water vapor is adjusted by changing the humidity from 49% to 95%. The measurement results show that the degree of coherence degrades with the increase of turbulence. The results obtained by this experiment have verified theoretical ones.

1998年9月22目に紀伊半島に上陸した台風9807号は, 中心の後面で吹き返しの風が強く, 気温の下降を伴った。強風による被害が最も顕著であった奈良では突風率が3を超え, 乱れの大きい風が吹いた。次に, この台風と過去に類似のコースを通過した3個の台風について, 気象要素の時間的変化の特徴を比較した結果, 台風後面の吹き返しの方がとくに強いとは限らなかった。また, 気温は, いずれの台風でも中心後面で下降しているが, その傾向は台風によって異なっていた。最後に, 著者が開発した台風気圧場客観解析法を適用して, 10分間間隔で気圧場の解析を試み, 強い風が記録された気象官署6地点について地表風を算出して, 実測地表風と比較した。その結果, 風向については, ほぼ一致した。一方, 風速については, 京都, 大阪および奈良ではほぼ一致しているが, 上野と和歌山における台風中心後面の強風は過小評価となった。, Typhoon 9807 (VICKI) having hit the Kinki District on Sept. 22 in 1998 caused severe disasters by high wind. The high wind appeared in the rear side of the typhoon eye with abrupt air temperature falling.Time change of the meteorological elements are compared with those of the three typhoons 6118 (NANCY, the second Muroto Typhoon), 7916 (OWEN) and 8917 (ROGER) having taken courses similar to Typhoon 9807. In these three typhoons, high winds were also recorded in the rear side of typhoon eyes at some weather stations. The course of typhoon pressure centers determined by the objective analysis in the ten-minutes interval indicates meandering in 15 km width and shifting on the left-hand side of the course determined by Japan Meteorological Agency (JMA). At seven weather stations of JMA, the basic surface winds are computed from a radial pressure profile approximated by the Schloemer's formula, and speed and direction of the surface wind are estimated after correction based on statistics for typhoons having hit in the past years. The estimated wind direction coincides with the observed one. However, at Ueno and Wakayama weather stations, the wind speed in the rear of the eye shows an under estimation.

近畿地方と中部地方にある消防本部の気象観測網を中心して台墨9807号の気象状況を調べた。近畿地方で瞬間風速が50m/secを超える強風域が4ヶ所あり, その発生時刻は最低気圧とほぼ同時の場合と約1時間後の場合に分かれた。合成レーダ図との比較により, 後者の強風は台風の背後にできる降雨帯の周辺で発生し, その風向は台風の回転方向と台風の中心に向かう法線方向に分かれた。その他, 気温, 湿度, 降雨量, 気圧についてこの台風の地上での詳細な気象状況が明らかになった。このように, 台風の地上での気象情報の収集には消防署の細かい気象観測網は大変有用であることが分かった。, Meteorological elements on the Typhoon 9807(Vicki) were investigated using the weather observation network at fire stations in the Kinki and Chubu districts. There were 4 areas in Wakayama, Nara and Mie, where the max instantaneous wind velocities exceeded 50m/sec. In Tanabe City in Wakayama the max instantaneous wind velocity was measured almost simultaneously with the min atmospheric pressure. In the other areas the max instantaneous wind velocity was measured almost one-hour after the min atmospheric pressure occurred. The latter strong winds were expected to be related with a rain band behind the Typhoon 9807.

台風9807号による建物の強風被害調査を行い, 建物の被害分布, 近畿圏の主な歴史的建造物の被害の概要を明らかにした。とくに, 建物の被害が多かった奈良盆地における市町村別の建物強風被害について, 被害把握に対する航空写真の有効性と問題点について検討を行った。その結果, 世帯ごとに求めた建物被害率と航空写真から求めた建物の被害率との間には市街地において良い相関があり, 建物強風災害の把握に有効であることがわかった。, Strong wind damages to buildings and houses by Typhoon 9807 were investigated. The damage rate was obtained from public reports and field investigation. The rate of buildings and houses covered with the sheet shielding from the rain, here we call "sheet rate", was counted by the aerial photos. These two damage rates have a good correlation in the urban area in Nara Basin.

本稿は, 1998年9月下旬に近畿地方を中心に, 東海, 北陸, 東北地方におよぶ広範囲に被害をもたらした台風7号の奈良盆地周辺の被害状況を, 上空撮影, 現地調査, アンケート調査により明らかにするとともに, 海岸から離れた内陸部で発生した強風の特性を, 地形が強風に及ぼす影響に焦点を当て, 考察するものである.アンケート調査および気象官署の観測データをもとに, 奈良盆地周辺の強風域と風向の時間変化が明らかになり, さらに台風周辺の気流を模擬した風洞実験により, 地表面付近の流れが谷の走向や山地の位置によって複雑に歪められることが明かとなった。, Strong wind disaster in Kansai area due to Typhoon 9807 in September, 1998 was investigated by taking pictures from airplane, field survey and questionnaire.Mechanism of strong wind with the influence of topography is also discussed by flow visualization of air flow over 3 dimensional topographic model in the specially designed typhoon wind tunnel.

気象庁の平均風速の測定が風車型風向風速計に変更された1975年以降1994年までの20年間に日本本土に上陸した22個の顕著台風について気圧場から算出した基本地表風を基準として, 各気象官署の実測風のとの間の関係を調べた。その結果基本地表風と実測風の間の風向偏角と風速比は, 地点により, また風向により大きく変化していた。この変化の顕著な地点について検討したところ, その変化はほぼ地形と対応していた。また, この結果を解析対象外の台風9612号に適用して地表風を推算したところ, 中心付近の各地点において風向および風速ともに計算値は実測値とほぼ一致した。, typhoon; pressure profile; gradient wind; basic surface wind; Harmonic analysis

1955-1994年に日本本土に上陸した51個の台風について, Schloemer(1954)の気圧分布式を用いて, 以前に著者たちが行った気圧場の解析よりも精度を高めて解析をやり直した。その結果を利用して, 傾度風風速を算出し, super-gradientの補正を行って, 基本地表風速を求めた。近畿地方の気象官署のうちの6地点について, 基本地表風速と実測風速の比の値と傾度風の風上方向の数値化した地形との関係を調べた。その結果, 京都, 彦根, 和歌山では, よい対応を示したが, 神戸, 大阪, 奈良では, 対応が悪かった。また, 和歌山の風速比について, 風向方向に伴う地形の影響の差を除去した残差には, 1975年以降の値について有意な減少が見られた。, The radial pressure profiles of 51 severe typhoons making landfall for the period of 1955-1994 were approximated by the formula presented by Schloemer (1954). The gradient wind was computed from the analyzed pressure pattern, and the basic surface wind was estimated after a super-gradient correction. The ratio of the observed surface wind speed to the basic surface wind speed has a good correlation to a numerized topography in the upwind direction in Kyoto, Hikone and Wakayama. However, in Kobe, Osaka and Nara, this relation is not good. In Wakayama, the residuals of the wind speed ratio from the distribution represented as sum of the Fourier Series have a significant decrease after 1975, when the anemometer for the 10-minute mean wind speed measurement changed.

京都大学防災研究所暴風雨災害部門において文部省科学研究費自然災害特別研究などの補助を得て約30年間にわたって行ってきた台風とその風災害に関する研究の成果に基づいて、台風の風災害を予測する方策をまとめた結果である。台風の進路予報については気象庁を中心に大規模な研究が行われてきたが、それに伴う災害予測までを行う手段についての研究は従来行われていなかった。台風をモデル化しその進路その他パラメータの性質を明らかとし、それを利用して実際の台風が南方洋上にある間にその台風によって生じるであろう災害を定量的に予測する手法を提案するものである。, A new scheme for the prediction of typhoon wind damages in Japanese main islands is proposed. A model typhoon profile was reduced from the results of objective analysis of past severe typhoons hitting Japanese Islands. The surface wind speed is estimated from the gradient wind balancing to the moving circular pressure pattern. Combining these knowledges and the damages to surface wind speed relationship, the new scheme to predict typhoon wind damages was formulated.

To consider aeroelastic instabilities of prismatic high-rise buildings in strong winds, I.e., vortex induced oscillation or galloping, unsteady aerodynamic forces must be investigated as the external forces acting on building. From this point of view, wind tunnel experiments were performed to obtain information of the fluctuating pressure on side face of buildings, which are subjected to the forced harmonic oscillation with a fundamental linear mode in a boundary layer. In the previous paper we presented about the case of the oscillating square prism. This paper presents the characteristics of fluctuating pressures of other two type rectangular prisms. One type prism has the depth-breadth ratio equal to 2 which is the model of flow reattachment. Other type prism has the depth-breadth ratio equal to 0.5 which is the model of perfect separation. And the comparison of 3type prism (spuare and 2type rectangular prism) is discribed.

Along with the recent progress in earthquake engineering, a bulk of technical information is now available pertaining to seismic resistant design, analysis, construction and retrofit of buildings and lifeline physical systems. At the same time, well developed methods are in place to evaluate the system's seismic performance not just from physical but also from functional points of view. This paper presents a quantitative method of evaluating the lifeline seismic performance analysis for water and electric power systems utilizing Geographic Information Systems. Taking new damage models and system redundancy into consideration, the performance degradation due to earthquake is clearly characterized visually. In addition, lifeline system interactions which have been observed under earthquake conditions are evaluated quantitatively.It indicates that designing effective retrofitting and/or restoration strategy, the interaction effect should be taken into account.

The 1995 Hyogo-ken Nanbu Earthquake have adopted the seismic intensity of JMA(Japan Meteorological Agency) scale 7 since The 1948 Fukui Earthquake. Although the response spectrum is one of tools to grasp the basic reasons of structural damage we could not calculate it in the severely damaged area by this earthquake because observed records of ground motions were not enough near source region. Therefore, we calculated theoretical acceleration response spectra at the ground surface in the region near the earthquake source based on the spectral moment method. To estimate earthquake motion on the ground surface the theoretical formula of earthquake motion at base rock level was derived. The amplification effect of the ground was introduced by using the multiple reflection theory. Theoretically estimated response spectra were modified by the response spectra calculated using observed earthquake motions.

The characteristics of the disturbances near the equatorial tropopause were examined. Particularly, the amplification mechanism of the Kelvin wave and its relation with the basic state were carefully investigated. Most of the disturbances with period larger than several days have maximum amplitude near the tropopause. The amplitude near the tropopause is at most two times larger than 200 hPa. It can be explained by 1) density decrease with heoght 2) weak dissipation in the upper troposphere 3) wind shear near the tropopause and 4) N increase with height. However, remarkable amplification of Kelvin wave with period larger than 20 days in specific year, season (sometimes its amplitude is larger than 20 ms-1) cannot be fully explained in that way.In about ten years (1983-1993), such remarkable amplifications were observed several times, mainly in the northern winter and spring. It is suggested that the longitudinal change of the basic zonal wind can make effect in such amplification; amplification appears in the region where the basic easterly becomes stronger as we go to the east.

To consider aeroelastic instabilities of prismatic high-rise buildings in strong winds, I. E., vortex induced oscillation or galloping, unsteady aerodynamic forces must be investigated as the external forces acting on building. From this point of view, wind tunnel experiments were performed to obtain information of the fluctuating pressure on side face of buildings, which are subjected to the forced harmonic oscillation with a fundamental linear mode in a boundary layer. This paper presents the characteristics of fluctuating pressures on the side face of the oscillating square prism. The phase angle between fluctuating pressure and the displacement of the prism appeared positive value near the resonant velocity. The total work done by unsteady aerodynamic pressures suddenly jumped up from negative to positive near the resonant velocity. Mainly, the pressure on the lower part of building contribute to the immediate change of the work.

Spatial distribution of wind and turbulence characteristics over the mountainous region are investigated. Field observations of wind by propeller anemometers were made along the test power transmission line (Tsuruga Test Line) near the ridge. In this area, northerly and southerly wind direction is dominant due to east-west direction of the ridge line.Therefore, analysis was made for the cases of the north wind and the south wind.However, in the cases of the southerly wind, strongest wind cases at the top of the No. 3 tower among other observing points are seen a little easterly deviated wind case. These cases can be classified into a different group of data from other southerly wind cases.Different spatial distributions of wind characteristics were found among these groups. The difference between the north wind and the south wind may be attributed to the local topography, because the ridge line is located a little south of the test line. It is considered that slight deviation of wind direction over this area made the difference between two groups of the south wind due to the topography. In relation to the turbulence intensity, integral scale of the turbulence for the north wind is larger than that for the south wind.

Rainfall characteristics over the HEIFE area in the Northwestern China are investigated as an example of rainfall it the midlatitude arid area. Especially, its relations to the synoptic weather conditions are focused on. Results show that the rainfall within HEIFE area is mainly caused by the wave disturbances over polar front. Rainfall amount observed at the surface is revealed to be related linearly to the elevations of each station and decreased to 100 mm/year at the bottom of Hexi Corridor, 70% of which is occupied by desert.The possibility of rainfall is considered to be determined by the upper air conditions.During the summer, rainfall is sufficiently expected from the standpoint of water content and stability. But because of high lifting condensation level and mean downward air motion over the desert, rainfall is only possible when the large scale external forces like wave disturbances over polar front exist on this region. Meanwhile in winter, water content is quite small and stability shows nearly neutral.

In 1993 and 1994, we had two earthquakes in Hokkaido island, Japan. Both earthquakes accompanied with tsunamis. From our field study, radio communication of tsunami warning systems and issue of evacuation are inadequate in almost every local area due to lack of the information facilities transmitted to individual residents and misunderstanding on tsunami behavior by local government. We have sequential events in the process of the communication in which every event may introduces and enlarges the disaster damages.In order to mitigate the human damages due to immediate coming tsunamis or well-prepared tsunamis after earthquake, it is necessary to arrange tsunami evacuation manuals in every local areas. In the case of gigantic tsunami in densely populated area, disaster management is very important to mitigate human and property damage. Numerical simulation technique is very useful to give practical information about the tsunami behavior such as the highest tsunami and the shortest arrival time. In emergency management, humanware management and commandware one are also very important as well as hard and software management at the moment of disaster occurrence.

Velocity and turbulence measurements for flows in compound meandering channels of three different sinuosities (s) were undertaken in a relatively small scale laboratory flume.A 2 component fibre optic cable laser Doppler anemometer (FLDA) was employed for the measurements. Information on 3 dimensional structure of the flows in the channels were obtained. Growth and decay processes of secondary flow along the meandering channels were also clarified.It is of particular interest that secondary flow structures in the meandering channel of s=1.37 are totally different between before and after inundation. An area producing strong shearing is observed at around the bankfull level in the crossover region for overbank flows. These unique phenomena are introduced by horizontal interaction between the main channel flow and the flood plain flow at that level. Consequently, despite their geometrical similarities, dominant mechanism for compound meandering flow is dissimilar to that for straight compound flow.

The sea-level pressure profile in Typhoon 9313 (YANCY) hitting on the Japanese Islands on September 2-4 in 1993 was analyzed by the use of the Schloemer's equation through the objective method. At the time of passing through at the Kume Island in the Nansei Islands, the radius of maximum wind was 22km with coincidence to the area with strong echoes on the radar image, and it increased to 59km at landfall on the South Kyushu. The filling rate after landfall was smaller than that estimated from the Matano's theory. At landfall on the Japanese Main Islands, the pressure gradient at the radius of the maximum wind was larger than that of Typhoon 9119 (MIREILLE).However, owing to relatively small translation speed, the maximum wind speed was almost equal to that in Typhoon 9119. At stations inside the maximum wind radius, the surface wind speed got close to the gradient wind speed and sometimes exceeded it.

The three eastward-moving disturbances localized near the tropopause was investigated with using IMA (Japan Meteorological Agency) global analysis data during November 1992-February 1993.These events are considered to be the equatorial trapped internal Kelvin waves with upward energy propagation.These waves have large amplitude only in the several ten longitudes around the western Pacific.The wave form is far from sinusoidal.Changing to the westerly and warming is much more rapid than changing to the easterly and cooling.

The statistics of Tatsumakis occurred in Japan are investigated for 32 years from 1961 to 1992. The total number of the occurrence of Tatsumakis for 32 years is 538 and the yearly average is 16.8. The largest probability of the occurrence in each prefecture in a year is Okinawa and the value is 7.49. The relative frequency of the cause of the occurrence of Tatsumakiis as follows; 24.3% for typhoons, 39.0% for fronts, 17.8% for lows and 18.8% for others. The 60% of Tatsumaki occur between July and October. The Tatsmakis associated with typhoons occur in the field near the coast line of the Pacific ocean.The yearly average of damages is as follows; 0.4 for the died, 23.5 for the injured, 27.6 for the completely destroyed houses, 329.8 for the partially damaged houses. The average of the damaged area is 119m for the width and 3.2km for the length.

The monthly mean data of sea surface temperature (SST) of COADS (Comprehensive Ocean-At-mospheric Data Set) was analyzed in relation with tropical cyclone activity in the Northwest Pacific in the period from 1951 to 1985.The original data of SST for mesh of two degree latitude and longitude interval is smoothed over five meshes to incooperate the scale of a tropical cyclone.The probability of tropical storm genesis shows the maximum value over the sea area with SST of 28.0-30.0℃.In the region with SST lower than 28.0℃, the probability decreases sharply with decreasing of SST. And in the region higher than 30.0℃ the probability also decreases.The interannual variation of the sea area with SST in 29.0-30.0℃ is distinct. The annual total area with SST of 29.0-30.0℃ decrease in 1965, 72, 75, 76, and 82 distinctively.In these years except for 1975, El Nino Event occurred in the Eastern Equatorial Pacific, and it is considered that the event caused to reduce the area with SST in 29.0-30.0℃.In these years, the area with SST in 28.0-29.0℃ increases conversely.Therefore, the total area of 28.O-29.0ｰC does not change significantly, and tropical storm genesis does not change largely even El Nino year.The annual number of tropical strom genesis in the area under study changes with the area with SST in 28.0-30.0℃, with the correlation coefficient of 0.57.The deepening rate of central pressure increases with SST in the latitudal belts except for 6-8ﾟN.The deepening of central pressure is distinct between 130ﾟE and 160ﾟE, where SST is higher than the other longitudal zones.

The typhoon 9119 has left the new largest peak gust speed records at many stations compared to the largest wind speed records.Some researchers pointed out special feature of large turbulence of this typhoon.However, it is necessary to consider recent changes of characteristics of anemometers.In this paper, the response of the propeller anemometer is studied using the observed data at Tsuruga test power-line.Propeller anemometers can not respond to wind fluctuations with short duration (less than around 1 sec). Recent improvement of the dynamic response of the anemometer has resulted in larger peak gust speed.If large deviations from the wind direction happens from overshooting of wind vane of the propeller anemometer, the averaged wind speed by the propeller anemometer may be underestimated.As the result, apparent larger gust factor may be obtamed.

Severe storm of Typhoon 9119 (MIREILLE) caused damages to about 680 thousand houses over the Japanese Islands11.The distribution of the surface wind speed of this typhoon was estimated from the objectively analyzed pressure pattern2), in consideration of the characteristics of a radial wind distribution and the surface roughness.The estimated wind speeds represent well the surface wind speeds observed at the weather stations.The damage rate of houses is not clearly related with the maximum estimated wind speed, but the frequency of loss occurrences of houses, F1, is related closely with the maximum wind speed, Vs, with the correlation coefficient of 0.71.F1increases in proportion to the 5.5th power of Vs and the relation between them is represented as F1=3.9 x 10-4 Vs55, where F1 and Vs are measured in % and msー1, respectively.The result obtained in this study will be applied to simulate the house damage distribution by severe thyohoons in a succeeding study.

A series of numerical experiments is performed on two-dimensional turbulence on a rotating sphere of several rotation rate, with an attention to the pattern of flow field. In the non-rotating case, isolated coherent vortices emerge in the course of time development similarly to the planar two-dimensional turbulence.As the rotation rate increases, however, the temporal evolution of the flow field changes drastically and there appears an easterly circumpolar vortex in high latitudes. The flow field is then anisotropic at all the latitudes and elongated in the longitudinal direction.

Just after the second world war, typhoon 4516 which landed on Makurazaki, Kyusyu island in 17 September 1945 with the atmospheric pressure of 916.4mb generated severe damages in Hiroshima. The nationwide loss of lives due to the typhoon was 3128 and a two thirds of the dead was counted in Hiroshima.The factors which enlarged the damages in Hiroshima are 1) a lack of proper meteorological observation systems, 2) delay of debris and flood control works and 3) A-bombed wide area. They were all influenced by the war which declined disaster prevention potential. Due to the war, the government cut down the budget of land development and draft of civil engineers made the public works discontinuous and discontent.

Around noon of June 27, 1991, strong gust (Jinpu) accompanied by down draft in the thunderstorm was observed in the eastern part of Okayama City. 18 successive electric poles were blown down.This gust was observed systematically in the southern part of Okayama Prefecture. And the peak gust speed of this Jinpu was estimated to be about 50 m/s. The electric pole failure may be explained by this wind speed when we consider non-stationary effect of the gust.

In the present paper, we assume the swirling motion of tatsumaki as the Rankine vortex moving with a constant velocity and analyze the unsteady horizontal flow at any point in the tatsumaki path.The inertial force on bodies due to the action of unstady/ accelerating flow is obtained by using the velocity potential for inviscid flow. The inertial force and the drag which is dependent on the square of the fluid velocity may be combined with the Morison's equation, which constitutes the total fluid force.The results are discussed and examined, comparing to the steady-state wind loadings with a constant velocity.

For the severe Typhoon 9019 (FLO) having made landfall on the Kii Peninsula at 20:00 JST, Sept. 19, 1990, the radial pressure profile is represented by the Schloemer's formula with an objective analysis method. Data in the typhoon center region is interpolated by a time-space conversion, and a time series of pressure pattern was obtained with the ten-minute interval by the analysis. As the wind balancing to the analyzed pressure pattern, the gradient wind speed, Vgr is computed. The ratio, Rv of the observed surface wind speed to Vgr is investigated in relation to topography, and it is shown that Rv increases inside of the eye wall.On a day before the landfall, when the typhoon passed near the Tanegashima Island with the central pressure of 920 mb, a developed rainband passed over this island. In the frontal zone of the rainband, horizontal convergence of 1.0×10-3s-1 s1 is evaluated, and in the rear horizontal divergence of 6.9×10-4ｓ-1 is seen.

This work concerns to a part of study on typhoon-induced storm surge as one of the important factors at considering the coastal hazards and related protection works. Main interest is concentrated to the problem on a nonlinear effect in the shallow waters of the coastal and shelf zones at passage of a typhoon. In order to find dynamical mechanism of the nonlinear effect, a simple theoretical model is introduced first. The result suggests that there are various possible patterns of the sea level variations as the nonlinear effect, even after eliminating the predicted astronomical tides and the reversed barometric effect. As an example of the recent storm surges, a case of the typhoon 9119 is introduced with a notice about the observed variations in relation to the patterns of the theoretical model. With the dynamical understanding of the storm surge, a more advanced prediction and protection works could be expected in practice referring to the observations and numerical simulations.

Typhoon 9119 (MIREILLE) making landfall at 1600 JST, Sept. 27, 1991 caused high wind disaster through Kyushu and Tohoku Districts. Characteristic features of this typhoon is investigated by pressure and wind analyses.Every ten-minute interval after landfall, pressure pattern is represented with the Schloemer's formula by the objective analysis method. In this analysis, we interporated the pressure data in the near center region of the typhoon by the time-space conversion, and the gradient wind is computed based on the computed pressure pattern.The gradient wind grew more intense after landfall and the intense wind region exceeding 50 ms-1 passed through the mountain part of Oita Prefecture and Hiroshima Bay, where the severe disasters by high wind were caused.About 2.5 hours after passing of the typhoon center, a pressure-dip with the maximum drop of 7.5 mb was observed through the northern part of Kyushu District and the western part of Chugoku District, and the life time of the dip exceeded 7.5 hours. At passing of the pressure-dip, peak gust of 20-40 ms-1 is observed, and it is considered that the investigation of this phenomenon is also important for a high wind disaster prevention work.

At the midnight on 29 April 1991, a cyclone accompanied with storm surges hit the southeast area of Bangladesh. Unfortunately, the the maximum anomaly of the storm surges simultaneously occurred at the spring high tide. The highest tidal level observed in Chittagong was 7.875 m above MSL, therefore every coastal dike was overflowed by the storm surges and flooding occurred at the coastal lowland and islands. The number of the dead was more than 130, 000, which was the fifth worst storm surge disasters in the world since the 13 th century. After the 1970 storm surge disasters which generated severe damages in the central of Bangladesh, construction of cyclone shelter and Cyclone Prepardness Programme (CPP) have been promoted to reduce the disaster victims. Nevertheless, these projects are not enough to be effective at the southeast area. Through the field survey, the characteristics of the storm surges in Bengal bay and spatial distribution of human and property damages and prepardness of countermeasures are analyzed.

The Typhoon 9019 landed at Kii Peninsula on 19 th September 1990. The high wind blew in these districts and the peak gust of 59.5 m/s was observed at Shionomisaki, which is the highest wind in the history of meteorological observation at Shionomisaki weather office. Damages to houses caused by the typhoon were investigated statistically. The rate of damage is too small, compared with those of the several typhoons in the past, especially the Isewan typhoon.The Tatsumakis during the passage of the typhoon are also reported.

A nonlinear shoaling model in frequency domain dervied from the variable depth Korteweg-de Vries (KdV) equation, equivalent to the 'consistent shoaling model' by Freilich and Guza (1984), was used to predict spectral changes of 1-D random waves.A random wave experiment with Pierson-Moskowitz spectrum was done to get detailed data of wave transformation over a uniform slope.The model overestimated the observations even in the region where there, were no wave breaking.In order to make the agreement between the predictions and experimental observations well, the frequency domain KdV shoaling model was modified to represent the dispersion relation and shoaling of linear component waves. As a result, the agreement between the predictions and observations in the shoaling region became better.An energy dissipation term must be included in the modified frequency domain KdV model to apply to the breaking region.

Urban areas developing over inclined land near the base of mountains have sometimes been damaged severely by flood hazard with water and sediment overflowing from river channels.For the purpose of the prevention and mitigation of this damage, recent flood damage of river channels was researched to find out its essential aspects.Revetments destruction, one of its main aspects, have been studied by continuing fundamental experiments.Damage of revetments model can be determined by two factors, current velocity and bank slope.One of the other characteristic features is conveyance and deposition of floating wood by flood water.Mode and concentration of transport of floating wood were discussed qualitatively, on their geometry relative to river channel dimensions, and on take-in process by peak flows, respectively. An experimental facility was designed to investigate the mechanism of this flood damage, while an optical triangulation system with a laser electronic theodolite of motor-driven was newly developed for the measurement of the experiments.

Characteristics of local strong wind in Amarube area were studied from the results of a wind survey for three years in this area. The topography of this area is a deep gorge flowing out to Japan Sea crossing a small mountain range parallel to the coastal line. Wind direction in the gorge is forced towards the parallel to the center line form the general wind. Wind coming into the gorge straightly parallel to the center line from the sea is strengthen by the topography. The wind flowing into the gorge with a little angle from the center line shows large intentity of turbulence. And power spectrum of wind in such a case shows wide energy peak.

Tropical wave disturbances which later developed into tropical storms over the equatorialPacific were analyzed using the satellite wind data and the rawin sonde wind data in July andSeptember, 1980. There were 10 tropical storms during these two months in the western Pacificand 5 of them were analyzed from the initial wave disturbances. Four out of five tropical stormswere developed from the easterly wave disturbances, which traveled with easterly wave along1ON from 150W in the eastern Pacific. There often existed the Mid Pacific Trough around160W, 30N. With the westward movement of easterly wave disturbances, the upper cold lowswere cut off from the Mid Pacific Trough and moved westward along 20N. These tropicalstorms in the western Pacific and in the eastern Pacific around 110W were both developed intotropical storms when they encountered the ascending motion area of the zonal circulation cells.

A simplified theoretical model is introduced in order to study storm surgeinduced by typhoon on the coast facing the western North Pacific. One of the aimsin this study is to find any storm surge which acts as if it were a forced Kelvinwave apparently. The other one of the aims is to know what difference can beexpected at the sea level variations as storm surge induced by a typhoonaproaching to the coasts facing western and eastern oceans. In order to help ourunderstanding, two cases of the typhoon 8506 and 8719 observed around theShirahama Oceanographic Tower and significant rises of the sea level at Shirahamain the period of July to September 1989 are also introduced to interprete some partof them as the considering typhoon-induced storm surges or a forced Kelvin waves.

[ABSTRACT] Both cyclonic and anti-cyclonic eddies formation are a common occurrence in the lee of the Island of Hawaii due to disruption of the trade winds between Maui and Hawaii to the north and the Kilauea volcano to the south. Recently, these eddies have been successfully tracked using GOES satellite imagery of sea surface temperature (SST). During an eddy spin up in March 1999, an increase in SeaWiFS surface chlorophyll was associated with cooler SSTs as recorded by GOES. Estimates of primary production inside and outside of the eddy were computed using a full-spectral depth-dependant primary production model with the satellite chlorophyll as input. New production was also estimated using field data from a similar eddy sampled in a previous year. New production increased 10-fold inside the eddy, while total primary production simply doubles and surface chlorophyll was only 2.5 times the outside values. It appears that eddies off the Big Island may contribute substantially to local new production rates, and that ocean color can be successfully used to track and calculate production due to these eddies.