| 研究実績の概要 |
The results from my multi-view satellite approach (ATSSG, Along-Track Stereo Sun Glitter technique) and from dual satellite comparisons have now been obtained. They yield surface current mapping and drift motion determinations for large pieces of floating debris that originated from the general the vicinity of the Fukushima Daiichi nuclear power station. These results have been carefully analysed and interpreted in relation to the well-defined changes in surface roughness that take place in the close vicinity of the debris field. I found that on 14 March 2011, some three days after the tsunami, a well-defined anomaly in the drift speed of debris lying some three quarters along the elongated debris trail developed. I have interpreted this speed anomaly in terms of a surface-roughness related restructuring of the wind, of the type first investigated systematically in laboratory work by Mitsuyasu and co-workers in the early 1980’s. If my interpretation of the anomaly is correct, it would represent the first time that this phenomenon has been observed on the open ocean. The implications for oceanography are wide since slicks, which create smooth zones of low surface roughness, are largely ubiquitous on the ocean surface. The near surface marine wind should then be highly structured and broken down into filaments where the wind is ducted and enhanced, due to the surface roughness damping introduced by the slick. This research has now come to a critical final stage in which I am searching for valid interpretations for the data and for the wider implications of my findings.
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