2004年の台風による高波は, 35年に及ぶ我が国の沿岸波浪観測史を通じて特筆されるものであった. 本土上陸台風数が10個に及び, その中でも, 台風0416号, 0418号および0423号は, 全国沿岸に顕著な高波災害をもたらした. 本稿は, これらの台風に伴う異常波に焦点を絞って, 全国沿岸で得られた波浪観測記録をとりまとめたものである. 室戸岬沖GPSブイ (水深100m) および室津港沖波浪計 (水深27m) が観測した有義波高14.21mおよび13.55mという値は, 全観測地点を通じても既往最大値であった. ナウファス最北観測点である留萌でも, 1970年以来の既往最大有義波高が観測された.

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This study first investigated the possibility that sands can serve as tracer particles in PIV (particle image velocimetry). Then we conducted hydraulic model tests on a movable bed for investigating migration velocities of suspended sediments associated with breakers. We further carried out numerical simulation using a κ-ε model to determine the correlation between the migration velocities of sands and the numerically-simulated velocity fields and vortex structures under the waves. We found that the sedimentation speed of silica sands derived from the PIV method is comparable to the sedimentation speed of sediments calculated by Rubey's formula, confirming that silica sands can serve as tracer particles in the PIV method. We also found that the migration velocities of sediments become faster than the water particle velocities where the water under wave motions moves in the same direction as the sedimentation direction of sands, thereby reinforcing one another; on the other hand, the migration velocities of sediments become slower than the water particle velocities where the water under wave motions moves in the direction opposed to the sedimentation direction of sands, thereby interfering destructively.

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A desastrous earthquake occurred in southern Chile at 22 th, 19 : 11 (GMT), May, 1960, the center of which was located by the Coast and Geodetic Survey, U. S. A. at 38° S, 73 1/2 W. Its magnitude is determined as 8.75 by the Matsushiro Observatory. The shock was felt by persons as far distance as 1000 km. to the north in Chile.
The earthquake and accompanying tsunamis killed 909 of Chilean people and damaged the cities of Concepcion, Valdivia, Puerto Montt, Ancudo etc. It caused crustal deformation along the Chilean coast between 37° to 42° S in latitude. The region around Lebu, Isla Mocha in the north and that around Isla Guafo in the south were upheaved about one meter, while the region between these two subsided about two meters at most. The tsunami originated along and, off the coast of subsided area where big waves assaulted three times with the hight of as large as 10 m and the last one was the highest, while the northern coast than Lebu was visited by far weak tsunami attaining only 1-2 meters in height.
It travelled over the Pacific to Hawaii killing 61 persons at Hilo, and to Japan killing 119 persons.
The energy of the tsunami was estimated as the order of 2 × 10²³ erg. It is about the same quantity with that of the Kamchatka Earthquake of 1952. One of the reason why it brought such a large damage to Japan is that the tsunami wave which once diverged itself from the origin again converged near Japan owing to the spherical surface of the globe.
The first phase of the tsunami reached along the coast of Iapan 22 hours later than the occurrence of the earthquake. But the arrival of the largest delayed 1-2 hours more. Its height (double amplitude) attained 5 meters at Hachinohe. It destroyed heavily these villages as Kiritappu in Hokkaido, Ofunato and Shizugawa in Tohoku District, and Ago Bay in Kinki District.

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本研究では, 可視化水理実験を行って砕波形式の相違による浮遊砂の移動速度を考究した. また, k-ε乱流モデルによる砕波の数値計算を実施して, 波内部の流速場と浮遊砂の移動速度を関連づけて検討した. その結果, 浮遊した砂の移動速度には, 波動運動に伴う流れが支配的であることが判明した. すなわち, S-P砕波では波動運動による流れと砂粒の沈降速度が同方向のときは, 両者が互いに強めあって砂の移動速度は水粒子速度より速くなるのに対し, 波動運動による流れと砂粒の沈降速度が逆方向ときは, 互いに弱め合って砂の移動速度は水粒子速度よりも遅くなる傾向を示した. Plunging砕波では, S-P砕波のように波動運動による流れと砂粒の沈降速度が弱めあう現象は顕著ではなかった.

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An influence due to non-spherical oceanic aerosol particles containing bubbles on estimation of the top of the atmosphere(ToA) radiance is clarified together with an influence due to relative humidity(RH). It is found that the difference of ToA radiance between the phase function of Maritime and Henyey-Greenstein with the same size distribution and refractive index is 0.5% for RH of 76% while that for RH of 99% is 1.3%. It is also found that the influences due to bubbles in oceanic aerosol particles and due to non-spherical parameter on ToA radiance are within arange of 0.3%. Meanwhile, influence due to RH on ToA radiance ranges from0.3 to 0.6%when the RH is changed from76% to 99%.

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日本における水表面での気体輸送に関する最新の研究成果を取りまとめ, この分野の研究の現状を報告した. また, これまで行われた「水表面での気体輸送に関する国際シンポジウム」で発表された論文を分類し, 国際的な研究の動向を明らかにした.

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