地面光譜資料與SPOT影像應用於水質定量推估研究

Water Quality Estimation Using Spectroradiometer and SPOT Data

蕭國鑫(Kuo-Hsing Hsiao) ； 吳啓南(Chi-Nan Wu) ； 廖子毅(Tzu-Yi Liao)

《航測及遙測學刊》 10卷2期 (2005/06) Pp. 169-182

https://doi.org/10.6574/JPRS.2005.10(2).4

摘要

SE-590地面光譜輻射儀(Spectroradiometer)於接近同一時刻，量測德基水庫水體與標準白板的光譜輻射強度(radiance)，換算為反射率後，再與水質檢測之葉綠素A、懸浮固體與透明度等參數施行多元迴歸分析(multiple regression)。另亦以德基水庫為例，利用同一天獲取的SPOT影像、SE-590高光譜資料模擬SPOT三個波段的光譜輻射值，再分別與各水質參數進行迴歸分析及評估迴歸統計資訊；結果顯示SE-590資料定量推估葉綠素A、懸浮固體與透明度水質的標準差為0.57μg/l、0.2mg/l及0.17m，SPOT資料推估之標準差為1.03μg/l、0.51mg/l及0.32m，SE-590資料模擬SPOT三個波段推估水質的標準差為1.77μg/l、0.49mg/l及0.37m。另以遙測多光譜影像之紅／綠及紅／近紅外光段比值法，定性分析水體中的葉綠素相對濃度分布，並確定比值愈小，葉綠素相對含量愈高。

關鍵字

遙測 ； 光譜輻射儀 ； 水質 ； 營養狀態

並列摘要

A field spectroradiometer was used to measure the spectral reflectance of water body. The reflectance was calculated as the ratio of surface water radiance to the standard whiteboard radiance nearly measured at the same time. Water samples were taken simultaneously for determining their chlorophyll-a, suspended solid and transparency. The relationships between those water quality parameters and spectral reflectance were analyzed using stepwise multiple regression to derive optimal prediction models. The multiple regression was also applied to the SE-590 simulated SPOT bands. The SPOT image of the same day was also analyzed using the same method to compare the statistical results.
It shows that the multiple regression models using the SE-590 reflectance data can get the best water quality prediction results. The evaluated RMS error of chlorophyll-a, suspended solid and transparency of water quality parameters are 0.57μg/l, 0.2mg/l and 0.17m, respectively and the RMS errors are 1.03μg/l, 0.51mg/l and 0.32m for SPOT data, respectively. The SE-590 simulated SPOT three bands data obtained the worst results because the RMS errors are 1.77μg/l, 0.49mg/l and 0.37m. Further, The band ratio of red/green and red/NIR were used to detect the chlorophyll-a relative distribution qualitatively, and assures that the ratio is less, the chlorophyll-a is abundant in TEKEE reservoir.

並列關鍵字

Remote sensing ； Spectroradiometer ； Water quality ； Trophic state