以SBAS-InSAR技術量測水庫集水區邊坡沖蝕變化

Monitoring Soil Erosion Changes on Slopes Through SBAS-InSAR Technology

謝渝棋(Yu-Chi Hsieh) ； 蕭宇伸(Yu-Shen Hsiao) ； 卓宥瑄(Yu-Hsuan Cho)

《中華水土保持學報》 53卷1期 (2022/03) Pp. 35-42

https://doi.org/10.29417/JCSWC.202203_53(1).0004

摘要

本研究採用合成孔徑雷達干涉（Interferometric Synthetic Aperture Radar, InSAR）技術中的短基線差分干涉法（Small Baseline Subset InSAR, SBAS-InSAR），推估石門水庫集水區範圍於2015年之土壤年沖蝕速率，進而估計本集水區沖蝕量體。研究資料選用Sentinel-1衛星影像共20幅。SBAS-InSAR計算得之年沖蝕速率將與沖蝕針監測成果驗證，而SBAS-InSAR計算得之沖蝕量體則與土壤流失公式計算結果相互比較。本研究結果如下：（1）採用上升軌道與至少12幅Sentinel-1衛星影像計算能有較好的成果；（2）未考慮濾波時，在資料處理階段張力係數值選用0.25且不使用區塊平均法，有較佳之SBAS-InSAR成果，與沖蝕針監測成果相比，兩者相關係數值在自然邊坡達到0.56，整治邊坡則達0.51；（3）考慮濾波處理時，8公里之高斯濾波半徑能有較佳SBAS-InSAR成果，與沖蝕針監測成果相比，兩者相關係數值在自然邊坡達到0.67，整治邊坡則達到0.57；（4）SBAS-InSAR與土壤流失公式計算得之沖蝕量體，兩者有趨勢大致相同。

關鍵字

SBAS-InSAR ； 石門水庫 ； 土壤沖蝕

並列摘要

We use small baseline subset interferometric synthetic aperture radar InSAR (SBAS-InSAR) to estimate the annual soil erosion rate in the catchment area of Shihmen Reservoir in 2015 and then estimate the soil erosion volume of this catchment area. The study data are 20 Sentinel-1 satellite images. The annual soil erosion rates derived from the SBAS-InSAR are validated using those derived from erosion pins. The soil erosion volumes estimated using SBAS-InSAR are compared with those estimated using the universal soil loss equation (USLE). The results reveal that more accurate estimations of the annual soil erosion rate are achieved when at least 12 satellite images of the ascending orbits are employed. When filtering is not considered, the tension coefficient is 0.25 and block averaging is not used during data processing; this achieves better SBAS-InSAR results. Compared with erosion pin monitoring results, the correlation coefficient is 0.56 for natural slopes and 0.51 for remedial slopes. When considering filtering processing, an approximately 8-km Gaussian filter radius achieves the optimal SBAS-InSAR results; compared with erosion pin monitoring results, the correlation coefficient is 0.67 for natural slopes and 0.57 for remedial slopes. Finally, soil erosion volumes estimated using SBAS-InSAR and USLE display similar trends.

並列關鍵字

SBAS-InSAR ； Shihmen Reservoir ； soil erosion

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