遙測技術應用於台灣東部卑南溪河口懸浮沉積物之監測

近年來光學衛星被廣泛用來做大面積的環境監測，其中懸浮沉積物濃度（SSC）變化為眾多監測項目中相當重要的目標之一，在光學影像中懸浮沉積物的濃度越高，通常可以反映出越高的光譜反射率。有鑑於複雜的環境變因，前人研究大多由衛星影像獲取水體反射率，配合水樣採集的濃度紀錄，建立區域性的預測模型。卑南溪位於台灣東南部，發源於中央山脈，豐沛的颱風降雨與陡峭短促的河道，造就卑南溪成為台灣重要的沉積物輸出河。本研究彙整2005年至2014年，由官方公告的懸浮沉積物濃度監測紀錄，從中篩選符合實測日期的81幅衛星影像，再建立各波段光譜反射率與濃度的關係。在未經過大氣輻射校正前，近紅外光光譜反射率有優於其他波段的線性關係（R^2=0.5461）；引進暗體辨識法（DOS）進行大氣輻射校正後，其結果有更顯著的線性關係（R^2=0.7151）。為驗證此預測模型提升懸浮沉積物濃度監控頻率的成效，本研究後段另外以2011年為例，整合預測結果與全年的水文資料來分析濃度變化的控制因素。

關鍵字

懸浮沉積物濃度；卑南溪；光學衛星影像；大氣輻射校正

並列摘要

Suspended sediment concentration (SSC) is an important indicator of sediment output. Recently, some SSC predictions had been carried out by using optical satellites imagery in different areas. In general, the more suspension sediment in water can directly reflect the higher reflectance of solar radiation. Therefore, most studies developed unique relationships by relating field measurements of SSC to reflectance data from satellite imagery. In this study, we focus on the Pinan River estuary which is born from the largest river in eastern Taiwan. In order to identify an appropriate SSC-reflectance model, we combined our optical satellite images with the field data from 2005 to 2014. Actually, the near infrared band can represent better linear regression result (R^2=0.5461) than other wavelengths. And, there are several noises affect our results, including the depth of river, solar reflection, clouds. In order to improve the results, we used Dark-Object Subtraction (DOS) to remove the background water reflectance. In the final part, while getting a better result (R^2=0.7151) of predictive model, we used it to resupply the SSC data in 2011, and discussed the characteristics of sediments output with heavy rainfall events.

並列關鍵字

Pinan River Estuary ； Optical Satellite Imagery ； Suspended Sediment Concentration ； Dark-Object Subtraction

國際替代計量

遙測技術應用於台灣東部卑南溪河口懸浮沉積物之監測

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