Observation of Nearshore Plankton Blooms by Ground-Based Synthetic Aperture Radar

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Project title

Code/計畫編號

MOST105-2611-M019-016

Translated Name/計畫中文名

應用陸基合成孔徑雷達於近岸浮游生物群聚之觀測

Project Coordinator/計畫主持人

Tzong-Dar Wu

Funding Organization/主管機關

National Science and Technology Council

Department/Unit

Department of Electrical Engineering

Website

https://www.grb.gov.tw/search/planDetail?id=11880300

Year

2016

Start date/計畫起

01-08-2016

Expected Completion/計畫迄

01-07-2017

Bugetid/研究經費

785千元

ResearchField/研究領域

海洋科學

由於合成孔徑雷達可以在夜晚及各種天氣條件下操作，因此它成為海洋遙測應用的重要工具。其中一種應用即是偵測近岸浮游生物群聚及觀測它們的群聚特徵，因為通常這種群聚會導致海面上形成一層薄膜。雷達回波會帶回一些海表面的狀態資訊，而海表面的狀態受到波浪、波紋、或是類似浮游生物或油污所產生的物質的影響。波浪與波紋導致粗糙的海表面，而浮游生物的聚集使得海表面累積了表面介質，導致原本粗糙的海表面受到阻尼(dampening)效應的影響，表面變得光滑，造成雷達回波降低而使得雷達影像呈現暗色。以往相關的研究通常是使用衛載光學式感測器搭配衛載(satellite-based)合成孔徑雷達，有些研究是衛載合成孔徑雷達搭配空載(airborne)光學式感測器。而本計劃將使用陸基合成孔徑雷達來偵測及觀測近岸海面浮游生物。由於陸基雷達具有高解析力的特性，預期對浮游生物的分布將有較準確的觀測資訊。此外由於浮游生物會隨著海流而漂移，本計劃亦將針對不同季節期間，浮游生物的動態群聚分布以及動態面積大小進行觀測與調查。本計劃中另一個目標是希望建立一個基於電波散射理論模式的粗糙度參數反演方法，用以估算出海表面的粗糙度。預期此一工具能改善全偏極合成孔徑雷達資料的解讀，並能以合成孔徑雷達影像重建出海表面的粗糙度分布。 Synthetic aperture radar (SAR) has been a powerful tool for the applications of remote sensing to ocean science, since microwave radars are able to be operated regardless of sunlight and weather conditions. One of the important topics is the detection and characterization of nearshore plankton blooms forming sea surface film. Radar echo returns information about water surface conditions affected by waves, ripples, and materials such as plankton and oil pollution. The plankton distribution is related to the occurrence of low backscatter patterns in SAR imagery since the surface roughness is damped by the accumulation of biological surfactants released by the plankton blooms. Previous studies commonly use the satellite-based SAR and optical sensors jointly. Some studies take advantage of combined aircraft surveillance data and satellite SAR data. In this project, we will use the ground-based SAR system to detect and observe the nearshore plankton blooms. Because of the property of high spatial-resolution, compared to satellite-based SAR, the ground-based SAR is expected to provide more accurate distribution of plankton blooms. In addition, since plankton typically flow with ocean currents, the observation in this project will also include the dynamic area-size and dynamic distribution in different seasons. Another scope of this project is to formulate and solve the inverse problem of the roughness of the ocean surface based on an analytical EM model, the Integral Equation Model, which is chosen for the modeling of the surface scattering mechanism. This model-based method is anticipated to serve as important tools for improving interpretation of polarimetric ground-based SAR data; moreover, for reconstructing roughness characteristics of sea surface from SAR images.

Keyword(s)

陸基合成孔徑雷達
近岸浮游生物
電波散射理論模式
ground-based synthetic aperture radar
nearshore plankton blooms
wave scattering theoretical model

DSpace CRIS

Observation of Nearshore Plankton Blooms by Ground-Based Synthetic Aperture Radar

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