SURFACE CURRENT MAPPING IN COASTAL ZONES USING HIGH SPATIAL RESOLUTION SATELLITE DATA

2014 Fiscal Year Research-status Report

• Project/Area Number: 25610140
• Research Institution: Kyoto University
• Principal Investigator: ジョン マシューズ 京都大学, 国際高等教育院, 教授 (70649152)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: Wind restructuring / Mitsuyasu effect / stereo-satelite / atssg technique / surface currents / marine debris / Tohoku tsunami

Outline of Annual Research Achievements

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.

Current Status of Research Progress

2: Research has progressed on the whole more than it was originally planned.

Reason

The analysis phase described last year is largely finished and I am now writing up the results in the form of 1 (or 2?) scientific papers.

Strategy for Future Research Activity

As the research grant finishes this year, I am now in the final phase of bringing the results together, interpreting them and eventually producing scientific papers based on these results.

Causes of Carryover

Because the analysis phase finished on schedule, there has been no need to buy further satellite images.

Expenditure Plan for Carryover Budget

Conference travel finance will be required and further satellite images and analysis will be purchased as required.