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Field observation of wind fields has been carried out by using a doppler lidar and meteorological radars. Characteristics of fluctuational wind under cumulus convection and the growth of boundary layer including not only the effect of ground friction caused by surface roughness but also the effect of gust caused by up/down draft was examined and clarified. Some observed cases with the down flow under cumulus during passages of cold front were examined. The wind fields were simulated by large eddy simulation with canopy model, cloud physics model and boundary condition from simulated wind field by meteorological model WRF. The simulated wind fields consist with the observation. The wind speed near the ground increases with the down flow under the cumulus convection.

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.

Our research group is developing a platform to evaluate the strong wind risk of buildings. A data-base of configuration of building was made by field survey at some real cities. Residential or no-residential house, number of stories, configuration of roof, material of claddings and material of roof were chosen as elements of wind resistant characteristics. The method to extract the elements from the database constructed by the field survey was examined by relating to the numerical database of building configuration on GIS system. The procedure of extraction was proposed for some elements of wind resistant characteristics, i.e. residential house, number of stories, configuration of roof, material of claddings and material of roof.

Observations of the turbulence in the atmospheric surface layer have been made using sonic anemometer-thermometers on a meteorological tower (55-m tall) of the Observation and Analysis System for Local Unusual Weather in the Ujigawa Open Laboratory. This place is located in the suburbs of Kyoto and surrounded by low buildings and roads. In the winter and early spring of 2012-2013, turbulence data were measured at two levels (40 and 25 m) on the tower. For a preliminary examination, turbulence characteristics under near-neutral conditions are presented. Large-scale turbulence structures are sometimes identified from the wavelet variance spectra for the streamwise velocity components.

本研究では, ISO規格(ISO 16932)に規定された建物開口部におけるガラスの耐衝撃破壊性能評価方法に従って衝撃試験を行うことのできる試験装置を作成し, 種々の板ガラスを試験体として用いた衝撃試験を行い, 耐衝撃破壊性能を明らかにした。得られた結果をまとめると, 今回試験体として用いた普通フロートガラス(厚さ5, 6, 8, 10, 12mm), 強化ガラス(厚さ5, 6, 8, 10mm), 網入りガラス(厚さ6.8, 10mm)は, ISO規格に従う判定に不合格であった。合わせガラス(中間膜の厚さ30, 60, 90milの３種類とガラス厚さ3, 5mmの２種類の組み合わせ)ではISO規格に従う加撃体Ａ, Ｂ, Ｃによる, フィルム貼りガラス(フィルム厚さ50, 100, 350, 450μmの４種類とガラス厚さ5, 6mmの2種類の組み合わせ)では加撃体Ａ, Ｂによる衝撃試験に合格した。, Impact resistant test of glazing was carried out based on ISO 16932. An air-cannon, that is a missile-propulsion device, for the impact resistant test of cladding against windborne debris was manufactured. A series of tests of various kinds of glasses was carried out to investigate the performance of impact resistant and the characteristics of failure. The performance of sheet glasses, such as float, tempered, wired, laminated and filmed glasses was evaluated by the specification of ISO16932.

In this study, the large-scale temperature rise in the Japanese Islands was taken up. The daily values of AMeDAS in 2004 were used for data. Large-scale temperature rise was defined as the case when the deviation from the normal of the daily maximum temperature is 10℃ or more. First of all, the region and the season of large-scale temperature rise were clarified. Then, the generation was analyzed. The results are as follows.1) Large-scale temperature rise occurs mainly in the Sea of Japan coast from San-in to Tohoku. A lot of generations are also seen in Pacific coast and the Okhotsk coast from Kanto to Hokkaido. Many appear in spring.2) Large-scale temperature rise starts from West Japan, and shifts to East Japan. Moreover, it starts from the inland, and shifts to the coast. Before and after the generation of a large-scale temperature rise, the anticyclone advances toward the east around Japanese Islands. When the Japanese Islands are covered with the anticyclone, warm air is formed in the inland. The warm air is carried to the leeward coast by the southerly wind on the west side of the anticyclone. This wind blocks the invasion of a cool sea breeze, and promotes the temperature rise.

地表付近で吹く強風は時々大きな災害をもたらすことがある。この局地的な風の構造を空間的に把握するためには、現地観測を行ってその性質を調べる必要がある。ここでは、超音波風速計を多点に配置した観測に基づく結果を報告する。風向方向の風速変動の空間交換係数は距離とともに減少し、約200m程度で相関は無くなる。乱渦の2次元水平構造は、縦横比が5:3の長円を示す。間欠的に発生する突風は風速の急速な増加と同時に、運動量の大きな鉛直下向きの輸送を伴っていて、上空からの強風の下降を示唆している。, The structure of the spatial structure of the high winds were investigated based on the results of the intensive observation near the ground. Several sonic anemometers were installed in the horizontal line. Spatial correlation is evaluated up to 200m along wind direcion and the shape of the tubelent eddy was similar toi the ellipse with the ration of stream wise and lateral ratio of 5 to 3. The gust shows the sudden increase of wind speed and the downward transport of the vertical momentum was detected simultaneously in short duration.

It is known that the wind damage spreading of residential houses is more strongly affected by gust speeds rather than maximum wind speeds. Furthermore, the age and the structure of buildings influence outbreaks of wind damage. The authors proposed the method to estimate residential damage rate associated with typhoon by considering wind-resistant performance of houses and strong winds. The residential damage rate has been better estimated using modified wind speeds associated with building structure distributions in municipalities. Residential damage rate due to strong winds might be able to estimate better considering performances of houses such as roof form, exterior material and maintenance. Considerable affecters to estimate residential damage rate more correctly should be established.

2006年には台風や竜巻，突風による建物強風被害が多発した。とくに，9月の台風13号では八重山諸島や九州において多くの建物が強風被害を受けた。また，同台風は多くの竜巻や突風を伴い，延岡市の竜巻では3名の死者を出し，ＪＲ日豊本線の特急"にちりん"が脱線した。本報では，これら台風0613号による建物の強風被害を中心に，その特徴を検証し，防災・減災の観点から建物の耐風性能を高めることが必要であることを明らかにした。具体的な対策としては，1：屋根葺き材，屋上の設置物等の飛散を防ぐこと。2：雨戸や格子，耐風性能の高いガラスを用いるなど，飛散物に対する防備を高めること。また，3：軽量建物用の耐風設計を整備することが至急の課題であること。等である。, We had many strong wind disasters caused by typhoon, tornados and down bursts in 2006. Typhoon 0613 in September struck Yaeyama Islands, Japan, and significant damage to buildings and houses occurred. In Kyusyu, there was many damage to houses and buildings especially in Nagasaki, Saga and Hukuoka prefectures. This typhoon also brought a number of strong winds and a tornado that struck Nobeoka city in Myazaki prefectures. Three persons were dead and a train was derailed. This paper focuses on the characteristics of the damage to buildings and houses caused by strong wind of Typhoon 0613 and examined effective measures from the viewpoint of preventing and mitigating these disasters. To prevent the claddings and openings from the flying missiles is important to reduce the strong wind damage. The shutters and the wind resistant glasses are effective. To decrease the number of missile is also essential. The damage caused by lightweight houses is notable in urban area.

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.

本報告は，異常気象を引き起こす原因の解明と，それによってもたらされる災害の実態について述べたもので3部からなっている。第1部では，気象庁現業の数値天気予報モデルを用いて，熱帯大気中の季節内振動のアンサンブル予報に適した摂動を生成するように，成長モード育成法の改良を行った結果について述べている。得られた初期摂動は，位相速度が約30 m/sで東進する，対流とは結合しない，東西波数1のKelvin 波と良く似た空間構造を持っていることが示された。摂動の成長率は，中高緯度における傾圧不安定にくらべ大変小さいことがわかった。第2部では，強風特性を明らかにし，強風による被害予測の用に供するために，2004年の台風18号を解析対象として，厳島神社周辺の複雑な地形上における台風通過時強風の再現を数値計算により試みた結果について述べている。地形を再現できる程度の詳細な解析領域を使用した．計算には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。第3部では，2005年からデータの取得可能となったFY2Cの衛星画像データの精度を，MTSATのデータと比較することによって検証するとともに，FY2Cデータの補正方法を検討した結果について述べた。, This paper describes the analysis of various phenomena related with anomalous weather and its hazards, which consists of three parts. The first part describes a new method for obtaining initial perturbations appropriate to the ensemble forecast of the intraseasonal variability in the tropics, which was developed using the operational numerical weather forecast system of the Japan Meteorological Agency. The obtained initial perturbations have spatial structure similar to eastward propagating dry Kelvin wave with phase speed of 30 m/s. The second part shows a numerical method to simulate strong wind fields over complex topography during typhoon. For investigating the strong wind characteristics and predicting wind hazards. The PSU/MM5 and LES were used for the calculation of meso and micro-scale unsteady wind fields. The last part describes the results of the analyses using FY”C data for the research and prediction of Japanese abnormal weather, especially in Baiu season, which came into official operation in May, 2005 and observes a wide area of Monsoon Asia extending from Saudi Arabia to Japan from 104E, just above Singapore.

12, KJ00003639175, P, 課題

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.