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This manuscript summarizes my research history. My carrier started in 1981 as a research scientist at the Japan Atomic Energy Research Institute, where I was engaged in the research on the atmospheric dispersion of radioactive effluents. I moved to the Disaster Prevention Research Institute of Kyoto University in 1994. My major mission was the research of meteorological hazards such as typhoon, heavy rain and severe storms. In addition to the mission, I was involved in various researches in the related fields. Among them much of my times were devoted to the field observation of energy exchange between atmosphere and land surface. This field research inevitably guided me to the research on the satellite data analysis. It was also exciting to study environmental public health issues with a professor at the department of medicine in Kyoto University.

We have investigated the quality of track forecast for Typhoon Hagibis 2019 using ensemble forecast data from four major operational numerical weather forecast centers, ECMWF, NCEP, UKMO, and JMA. From six to four days before the landfall, the JMA forecast was the best among other centers, but the error increased sharply three days before the landfall. Compared to the forecast from 0000 UTC 9 October, the typhoon drifted westward about two days before the landfall in the forecast from 1200 UTC 9 October. Consistent with the westward track error, there was a northwestward bias of the environmental winds. The sensitivity analysis at the verification time close to the landfall indicates a large sensitivity to a low pressure disturbance located to the south of the typhoon.

This report shows the field observation results conducted in the summer of 2018. The intensive field observation has been carried out for two and a half months (from August to November) at the observation tower of Shirahama Oceanographic Observatory. During the observation, three typhoons (No.20, 21, 24) approached the Kii peninsula, and the typhoon Jebi (No.21) and the typhoon Trami (No.24) brought sever wind and wave conditions. The observed maximum significant wave height and maximum instantaneous wind velocity are 11.09m by No.24 and 55.79m/s by No.21, respectively. High wave conditions caused significant damage to measurement devices on the observation tower which are installed for wave observation at the level of 10m high from mean sea level. Fortunately, wave data measured by ADCP (Acoustic Doppler Current Profiler) has a good agreement with wave data by measurement devices on the observation tower, and there is no major problem in data collection during high wave and strong wind conditions.

Results of meteorological observations in summer and autumn seasons of 2018 on the 55-m tall meteorological tower and the field of the Observation and Analysis System for Local Unusual Weather in the Ujigawa Open Laboratory are presented. The Ujigawa Open Laboratory is located in the suburbs of Kyoto City. In summer of 2018, an unusual event of heavy rainfall occurred and high temperatures were recorded. On 5 and 6 July 2018, total rainfall of 286 mm was measured. In autumn of 2018, strong wind events were induced by the Typhoon Jebi (Typhoon No. 21) and the Typhoon Trami (Typhoon No. 24). The maximum wind speeds of 48.8 m s⁻¹ and 30.6 m s⁻¹ were recorded at the height of 24 m by the respective typhoons.

Q-vector analysis is conducted for the Baiu frontogenesis leading to the Heavy Rainfall Event in July 2018. The formulation of the Q-vector is reviewed, and a simple interpretation of the Q-vector is presented for a mid-latitude cyclone in the Northern Hemisphere. Q-vector divergence (convergence) is collocated with northerly (southerly) winds. Our Q-vector analysis indicates that the Baiu frontogenesis occurred in a Q-vector convergence zone in western Japan to the south of the northerly winds of Typhoon Prapiroon.

Typhoon Jebi made landfall over Kinki region on September 4, 2018 bringing with it strong winds and storm surge in along Osaka Bay. This is a comprehensive study carried out on the disaster caused by the typhoon. The study examined and surveyed the characteristics of strong winds, spatial distribution of gusts, lightning strikes, rainfall and damages to various structures. It also reports the outline of the meteorological features of the typhoon.

As the seismic isolation buildings become taller, the fatigue assessment of seismic isolation dampers against wind force have been necessary. In this paper shows fundamental studies on establishment of maintenance planning method in high rise seismic isolated building considering replacement of seismic isolation dampers.

This paper shows some results of intensive field observation carried out in the summer of 2016. The vertical profiles of currents and water temperature measured as well as wave and wind conditions, and salinity observations carried out at the observation tower of Shirahama Oceanographic Observatory. In the summer in 2016, one typhoon (TC16, MALAKAS) approached close to the observation site, and the high wave and strong wind conditions more than 40m/s captured during the observation. Under the high wave and strong wind condition, ADCP (Acoustic Doppler Current Profiler) measured high echo intensities for several hours, and this result indicates that strong mixing occurs. Water temperature variation at 30m deep has opposite phase to the fluctuation of salinity. This result means that low temperature and high salinity water approaches to the observation site. It is also found in water temperature distributions in November that some influences of the warm and cool water mass exist.

Factors causing diversity of operation forecast tracks for Typhoon Yagi 2013 are examined in forecast experiments using ECMWF OpenIFS. The models at three different horizontal resolutions were run from the initial conditions at 12 UTC 9 June prepared from the ECMWF analysis. The finest resolution model predicts northeastward migration and intensity closest to the operational ECMWF forecast, while the coarser models show erroneous westward bias and underdevelopment. Our experimental results suggest that the difference in the track may be attributable to the representation of the trough along the Baiu frontal zone through the change in the steering flow.

Field survey on the flood and sediment disaster which was happen in Tokachi and Tokoro River Basins in Hokkaido in 2016 is performed and the characteristics of the disaster is discussed focusing on levee break phenomena and disasters around bridges. Population density around rivers is low in Hokkaido. Hence, river width between right and left levees is very wide, even though flood discharge is small. As a result, long bridges over rivers from right levee to left one have not been constructed. On the other hand, short bridges over only main channel and connecting roads between levee and bridge are constructed. The connecting roads between levee and bridge decrease the river cross-section and increases the flood risk. Furthermore, land elevation on the floodplain tends to be lower than the river bed elevation in Hokkaido. As a result, the levee breaks without inundation phenomena was happen in Satsunai River. Additionally, flood water tends to return to rivers soon due to the high elevation of floodplain.

This paper shows some results of a field observation carried out in the summer of 2015. The vertical profiles of currents and water temperature have been measured as well as wave and wind conditions, and salinity observations have been carried out at the observation tower of Shirahama Oceanographic Observatory. In the summer in 2015, no typhoon approached around the observation site, and the high wave and strong wind conditions have not been captured during the observation. Several short-term rainfalls due to front and low pressure occurred, and it is reported that local areas in Shirahama town and neighboring towns suffered some damages with windblasts from late August to early September. It is found in the observation results of water temperature that the temporal variations of water temperature have a period of 3 to 6 days in the deeper layers like 20m deep and 30m deep. The cyclical fluctuation of water temperature at 30m deep has opposite phase to the fluctuation of salinity. This result means that low temperature and high salinity water approaches to the observation site periodically and that some influences of the water mass of the open sea exist.

The dissipation/development trend of tropical cyclones (TCs) approaching to the south coast of Japan Islands was investigated. Among 203 cases from 1979 to 2013, 23 cases (11%) developed more than 7.5 hPa and 66 cases (33%) dissipated more than 7.5hPa during their migration after crossing a southern reference latitude (27°N). For the developed case Typhoon Roke (T1115) and the dissipated case Typhoon Jelawat (T1217) atmospheric and oceanic environment along their tracks were closely analyzed. Roke passed over the Kuroshio region, when it began to develop, where the warm current (≥ 26℃) was thick and the tropical cyclone heat potential (TCHP) was high. Decrease of sea surface temperature (SST) caused by passage of Roke was low over the Kuroshio Current. It was considered that the thick warm layer suppressed the typhoon’s self-induced ocean cooling over the Kuroshio Current, which in turn brought about a favorable condition for intensification of typhoon. Jelawat rapidly dissipated though the oceanic condition was not unfavorable for development. According to the cyclone phase space (CPS) analysis, it was shown that Jelawat had already started its extratropical transition when it passed over the reference latitude, 27°N, as the upper westerly shifted southward.

This paper shows some results of a field observation carried out in the summer of 2014. The vertical profiles of currents and water temperature have been measured as well as wave and wind conditions, and salinity and dissolved oxygen level observations have been carried out at the observation tower of Shirahama Oceanographic Observatory. In the summer in 2014, a total of 4 typhoons (No.11, No.12, No.18 and No.19) approached to the Kii peninsula, and the high wave and strong wind conditons due to 2 typhoons (No.18 and No.19) have been captured during the observation. When the typhoons passed around the observation site, the high wave and strong wind occurred. However, the observation data of 2014 doesn't have clear shift of water temperature and salinity like the one by the typhoon No.18 in 2013. On the other hand, it is repeatedly found in the observed data that the reduction of water temperature and the increase of salinity happened simultaneously. This result indicates that the water temperature and the salinity around the observation site have some influence of the water mass of the open sea.

This paper shows some results of a field observation carried out in the summer of 2013. The vertical profiles of currents and water temperature have been measured as well as wave and wind conditions, and salinity and dissolved oxygen level observations have been carried out at the observation tower of Shirahama Oceanographic Observatory. During the observation, one typhoon (No.18, MAN-YI) approached to the Kii peninsula. When the typhoon passed around the observation site, the vertical mixing develops well, and water temperature at all measurement points show almost uniform distributions. It is also found during the typhoon passing that coastal upwelling through the Ekman transport happened clearly due to continuous southward wind. An EOF analysis decomposes the water temperature variation during the typhoon passing into 1) the increase and decease of water temperature and 2) the magnitude of the temperature difference in the vertical direction.

This paper shows some results of intensive field observations carried out in the summer seasons in 2012. The intensive field observations have been conducted at the observation tower of Shirahama Oceanographic Observatory (SOO), DPRI, Kyoto University. One of the aims of the observations is field data measurements to comprehend the vertical mixing process due to wind and wind wave. During the observations, one typhoon (TC17, Jelawat) hit the Kii peninsula and passed along the southern coast of Japan. In the observation, the vertical profiles of currents and water temperature have been measured as well as wind and wave conditions. The main results are as follows: Strong wind and high wave conditions have occurred when the typhoon hit the observation site. The water temperature felt down a few hours later the typhoons come close to the observation site. The observed results underline the needs for the continuous observation activities and multidimensional data analysis.

The severity of meteorological disasters spawned by typhoons critically depends on not only the intensity but also the track of typhoons. A slight change of the track of typhoons would induce a large difference in the intensity and spatial distribution of heavy rainfall and high winds. The present study explores the influences of typhoon tracks on the representations of heavy rainfall and high winds in numerical simulations of typhoon-induced events with the use of a regional meteorological model. The analyses are focused on high-impact typhoons over the Kanto Plain. A nesting capability is used to resolve convective storms embedded in typhoons at the 1-km horizontal grid spacing. A large variability in the representations of heavy rainfall and high winds is demonstrated.

Typhoons often reintensify after their transition to extratropical cyclones. In order to analyze the evolution of cyclone structure during reintensification, the typhoons which rapidly reintensified after extratropical transition were examined in view of describing the cyclone phase space (CPS) a recently developed tool to analyze cyclone structure. We found two different patterns of the cyclone evolution after extratropical transition in the CPS. One is characterized by strong cold-core structure (cold-core), and the other by warm-core structure without experiencing strong cold-core structure (warm-seclusion). The cold-core first showed strong cold-core structure, but eventually transformed to warm-core structure. Thus, the difference of two patterns can be said to be the transformation period from extratropical transition to warm-core structure, and is suggested to be related with the trough.

伊勢湾台風による強風被害調査をはじめとして，過去50年以上にわたって京都大学防災研究所で行われた強風被害調査を概観し，強風被害の実態と変遷を調べるとともに，強風被害から明らかにされた教訓を，構造物の耐風設計との関連において検討した。また，竜巻などの小規模擾乱による強風被害と台風による強風被害を比較し，小規模擾乱における耐風対策について検討した。また，強風による人的被害を防ぐための心得を示した。, The investigations of damage induced by strong wind like typhoon, tornado and other local severe storms which have been carried out by the wind research group in DPRI since 1960's, are reviewed in the paper. A lot of lessons can be extracted from the investigation to improve wind resistant design of houses and buildings. Most vulnerable part of houses to wind is a roof and claddings. As more than half of damage of window and doors are induced by flying debris, it is very important to protect wind glasses from the flying debris by shutter or other measure e.g. use of laminated glass. Most of accident to peoples happens outdoor, so it is safe for us to stay in a house and a building when typhoon or tornado is approaching. Ten lessons and seven directions to be safe in strong wind are given in the paper.

白浜海象観測所では，毎年夏期に台風接近時の気象・海象データ計測を目的とした集中観測を実施している．2011年の夏期集中観測は8/11-11/8の間実施され，観測塔による波高，潮位，海水温計測に加えて，ADCPによる流速分布計測，水深30mまで計測範囲を拡張した海水温計測が実施された．観測期間中，台風12号および台風15号が紀伊半島付近を通過した．観測塔近くでADCPにより計測された流速分布は，風の変化(特に南北方向)に対応した変化を示した．台風最接近時にはADCP設置地点(水深約9.2m)付近まで鉛直混合が発達していることが確認された．また，台風接近時の観測塔付近の波浪状況や水温の鉛直分布が異なる様子が計測されたほか，河川水位の上昇に対応した表層水温の低下も観測された．, This paper shows some results of a field observation carried out in the summer of 2011. The field observation have been conducted for three months (from August to October) at the observation tower of Shirahama Oceanographic Observatory. During the observation, two typhoons (No.12 and No.15) hit the Kii peninsula, and the current and temperature profiles have been measured under the storm conditions as well as wave and wind conditions. Under the storm conditions, the current and temperature profiles show uniform distributions in the vertical direction, and this means that vertical mixing develop well in the surface layer. After typhoon passed, water temperature decreased in 04 Sep. 2011. Electric conductivity also dropped down at the same time. It is expected that flood water from the river would flow into the Tanabe bay and reached to the observation area.

台風の発生過程における初期渦形成過程について, Top-Down仮説とBottom-Up仮説のどちらが実際の過程をよく説明するのか検証した。そのためにメソ気象モデルを用いて2001年18号台風Franciscoを再現した。再現されたFranciscoは現実より約3度北で8時間早く発生した。発生前には中層に約100kmスケールのメソ対流渦, 下層に複数の約50kmスケールの渦が存在した。これらの渦が接近したあとに, 多数の対流スケールの渦が発生し, 併合することで初期渦が形成された。メソ対流渦と下層渦の領域で渦度の鉛直プロファイルを調べると, メソ対流渦の領域では時間経過とともに渦度が中層から下層へ広がり, 逆に下層渦領域では渦度が下層から上層へ広がった。従って再現された初期渦形成過程では, 注目するスケールを変えることでTop-DownとBottom-Upの両方のプロセスが見られた。, The initial vortex organization (IVO) in the early phase of the tropical cyclogenesis is a matter of interest in current study. Two hypotheses for the process of IVO associated with MCVs are proposed. One is Top-Down, and the other is Bottom-Up. These hypotheses, however, have not been confirmed enough. Therefore, we investigate the IVO process in the Typhoon Francisco (2001) case by using numerical simulation, and which process is seen in two hypotheses. The simulated Francisco is organized at nearly the same time and location. In simulated TCG process, one MCV, several low-level cyclonic vortices (LLVs), and small-scale vortices (SSVs) are seen. SSVs are being merged gradually from 00 UTC 16 to 00 UTC 17. The merged vortex has monolithic PV area with many convective clouds. The vortex got intensity, and becomes tropical storm later. To investigate development of MCV and LLVs, we investigate vertical profile of PV at the MCV and LLVs areas. PV in MCV area extends from mid-level to low-level. On the other hand, PV in LLVs extends from low-level to mid-level. Therefore, the temporal evolution of vorticity in MCV area seems Top-Down, but that in LLVs area seems Bottom-Up.

1980年10月13日に宮崎平野上で発生した竜巻について，領域気候モデルPSU/NCAR MM5を用いて再現実験を行った。モデルの初期値に用いたデータの解像度が粗いにも関わらず，竜巻の引き金となったと考えられるメソサイクロンの再現に成功した。また，地形や海陸間の粗度長差が竜巻発生に与える影響を調べるために感度実験を行った。その結果，宮崎平野の北西に位置する九州山地が竜巻の元となるメソサイクロンを発生しやすい環境を作っている可能性が示唆された。海陸間の粗度長差については，3次元モデル内でのメソサイクロン発生に対する影響については確認できなかった。, On 13 October 1980, Typhoon 8019 spawned five tornadoes in Miyazaki Plain. In this study, we attempted to simulate the mesocyclone that have generated these tornadoes by using regional climate community model PSU/NCAR MM5. The spatial resolution of initial input data was very coarse, however, the MM5 simulation successfully reproduced mesocyclone that might have triggerd off tornadoes. The results of high-resolution simulation indicated that Kyushu-mountainous district induced the low-level strong horizontal convergence line and it amplified the vertical vorticity on Miyazaki plain. By contrast, differences of roughness length between ocean and land didn't have significant influence on vortical strengthening and generation of mesocyclones in 3dimensional model.

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.