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黒潮表層水の収束発散に関する研究 (2)
https://fra.repo.nii.ac.jp/records/2003378
https://fra.repo.nii.ac.jp/records/2003378387eacf4-1855-4ff0-ad39-f703bd95c5a1
| Item type | 紀要論文 / Departmental Bulletin Paper(1) | |||||
|---|---|---|---|---|---|---|
| 公開日 | 2024-04-25 | |||||
| タイトル | ||||||
| タイトル | 黒潮表層水の収束発散に関する研究 (2) | |||||
| 言語 | ja | |||||
| タイトル | ||||||
| タイトル | A STUDY ON CONVERGENCE AND DIVERGENCE IN SURFACE LAYER OF THE KUROSHIO – II DIRECT MEASUREMENT OF CONVERGENCE AND DIVERGENCE AT THE TOP AND BOTTOM OF SURFACE MIXED LAYER | |||||
| 言語 | en | |||||
| 言語 | ||||||
| 言語 | jpn | |||||
| 資源タイプ | ||||||
| 資源タイプ識別子 | http://purl.org/coar/resource_type/c_6501 | |||||
| 資源タイプ | departmental bulletin paper | |||||
| アクセス権 | ||||||
| アクセス権 | metadata only access | |||||
| アクセス権URI | http://purl.org/coar/access_right/c_14cb | |||||
| その他（別言語等）のタイトル | ||||||
| その他のタイトル | 表層混合層の上部と下部における収束発散の実測 | |||||
| 言語 | ja | |||||
| 著者 |
川合, 英夫
× 川合, 英夫× 坂本, 久雄 |
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| 抄録 | ||||||
| 内容記述タイプ | Abstract | |||||
| 内容記述 | In a previous paper (KAWAI et al., 1969), an interpretation that horizontal convergence or divergence at the top of surface mixed layer be mostly compensated by horizontal convergence or divergence. at the bottom of the layer and that there be two systems of helical motion facing each other, forming a convergence zone centered at a distance of a few nautical miles inshore of the current maximum was given upon results of direct measurement of the convergence or divergence at the surface with four current drogues. On use of three kinds of current drogues, direct measurements of horizontal convergence and divergence at the top and bottom of surface mixed layer were made aboard two research vessels, the Soyo Maru and the Shyn'yo Maru, and an airplane in the seas off the Nichinan Coast, Kyushu and off Shikoku in August, 1968. In Fig. 1 described are the three kinds of current drogue systems: the surface drogue system with a radar target at the top of an iron pipe and a big corner drogue, working also as a ballast, at the bottom at depths between two and three m, the subsurface drogue system only different from the former in suspending the same corner drogue from the bottom of the pipe by a rope at a depth of 30 m, near to the depth of the bottom of surface mixed layer and the colored air-photo rafts with a wooden cross beneath the sea surface. At the beginning of the measurement, the four surface drogues were launched at four apexes of a square with sides 1/4 or 1/8 nautical miles long. Successively, the four subsurface drogues were launched in the vicinity of each of the surface drogues. Before the arrival of the airplane on the survey spot, the four air-photo rafts were launched in the vicinity of each of the surface or subsurface drogues. The surface and subsurface drogues were recovered except for cases of dropping, but all of the air-photo rafts were expended. Analyzing photographs of blips of the surface and subsurface drogues on the radar scope and color photographs of the air-photo rafts taken aboard the airplane at a height of 4500 feet, the area S of quadrilateral made by each kind of drogues was calculated on the basis of eq. (2) in the previous paper. The horizontal divergence Q was calculated from time change in S on the basis of eq. (1) on page 24. Before, during and after the drogue measurement, BT lowering and GEK fix were made at the locations shown in Fig. 2 to obtain current and temperature fields forming the background to the convergence and divergence. Hydrographic conditions off the Nichinan Coast, Kyushu during August 19-20, 1968 and off Shikoku during August 23-24 are shown in Figs. 3 and 4. According to Table 1 showing location and velocity at the axis of the Kuroshio main and branch streams, the position of the axis of the branch stream off the Nichinan Coast fluctuated very much, but that of the main stream off Shikoku did not. Figs. 5 and 6 show temperature profiles and GEK currents off the Nichinan Coast and off Shikoku and the location of current drogues at about the time of launch and recovery. The drogue measurements were made four times; measurements I and II off the Nichinan Coast and measurements III and IV off Shikoku. Results of analysis of these measurements are shown in Figs. 7-10. In measurement III in the vicinity of the axis of the Kuroshio main stream well-defined and stable, the air-photo rafts showed a marked convergence, the surface drogues a convergence weaker than the former, and the subsurface drogues a divergence or a faint convergence. Measure- ment IV showed a tendency similar to measurement III, but did not exhibit such a pronounced contrast in convergence and divergence between different kinds of drogues as observed in measurement III. This may be attributed to the difference in the launch position between measurements III and IV. The launch position in measurement III corresponded to the zone of strong convergence, observed in 1967, at the surface at a distance of a few nautical miles inshore of the current maximum, while the launch position in measurement IV was located in the vicinity of the current maximum. Trajectories of drogues in measurements III and IV (Y and Z in Fig. 2, Lower) showed a confluence in the same manner as observed in the measurements in 1967. The confluence is, however, not necessarily accompanied by the horizontal convergence. In measurements I and II, it was difficult to determine what kind of characteristic band the trajectories of drogues corresponded to because of indefiniteness and fluctuation of the axis of the Kuroshio branch stream. Correlations between distributions of surface phytoplankton (Figs. 11 and 12) and horizontal convergence and divergence are indefinite in general, but distribution of Cyanophyceae off Shikoku (Fig. 12) may be explained as follows. The habitat optimum for Cyanophyceae may be surface water of the warm core in the Kuroshio. The surface water has a weak component of velocity toward the convergence zone centered at a few nautical miles inshore of the current maximum, and it sinks in the vicinity of the zone. Cyanophyceae does not sink and drifts downstream with the maximum concentration on 'the side of warm water of the zone. The results of the drogue measurement in 1968 does not contradict with the interpretations given upon the measurement in 1967, but some indefiniteness remained here needs further careful measurements on the basis of a more elaborated plan. With the difference in convergence and divergence between depths of surface mixed layer, the fact that fish larvae, hatched out from eggs floating at the surface, sink into a subsurface depth seems to result in an effective fertilization in the convergence zone at the sea surface and an avoidance of starvation by keeping its density of population sparse at a subsurface depth. | |||||
| 言語 | en | |||||
| bibliographic_information |
ja : 南西海区水産研究所研究報告 en : Bulletin of the Nansei Regional Fisheries Research Laboratory 巻 2, p. 19-38, ページ数 20, 発行日 1969-11 |
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| 出版者 | ||||||
| 出版者 | 南西海区水産研究所 | |||||
| 言語 | ja | |||||
| 出版者 | ||||||
| 出版者 | Nansei Regional Fisheries Research Laboratory | |||||
| 言語 | en | |||||
| item_10002_source_id_9 | ||||||
| 収録物識別子タイプ | PISSN | |||||
| 収録物識別子 | 0388-841X | |||||
| item_10002_source_id_11 | ||||||
| 収録物識別子タイプ | NCID | |||||
| 収録物識別子 | AN00181988 | |||||
| 情報源 | ||||||
| 識別子タイプ | Local | |||||
| 関連識別子 | nnf_k_2_19 | |||||
| 関連サイト | ||||||
| 識別子タイプ | URI | |||||
| 関連識別子 | https://agriknowledge.affrc.go.jp/RN/2010841382 | |||||
| 言語 | ja | |||||
| 関連名称 | 日本農学文献記事索引(agriknowledge) | |||||
