International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences
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Volume XLII-3/W11
Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLII-3/W11, 67–72, 2020
https://doi.org/10.5194/isprs-archives-XLII-3-W11-67-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XLII-3/W11, 67–72, 2020
https://doi.org/10.5194/isprs-archives-XLII-3-W11-67-2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

  14 Feb 2020

14 Feb 2020

OPTMIZATION OF BIO-OPTICAL MODEL PARAMETERS FOR TURBID LAKE WATER QUALITY ESTIMATION USING LANDSAT 8 AND WASI-2D

A. Manuel1,2, A. C. Blanco1,2, A. M. Tamondong1,2, R. Jalbuena1,2, O. Cabrera3, and P. Gege4 A. Manuel et al.
  • 1Department of Geodetic Engineering, University of the Philippines Diliman, Philippines
  • 2Training Center for Applied Geodesy and Photogrammetry, University of the Philippines Diliman, Quezon City, Philippines
  • 3Institute of Environmental Science and Meteorology, University of the Philippines Diliman, Philippines
  • 4German Aerospace Center (DLR), Remote Sensing Technology Institute, 82234 Weßling, Germany

Keywords: remote sensing, inland water, chl-a, bio-optical modeling, inversion

Abstract. Laguna Lake, the Philippines’ largest freshwater lake, has always been historically, economically, and ecologically significant to the people living near it. However, as it lies at the center of urban development in Metro Manila, it suffers from water quality degradation. Water quality sampling by current field methods is not enough to assess the spatial and temporal variations of water quality in the lake. Regular water quality monitoring is advised, and remote sensing addresses the need for a synchronized and frequent observation and provides an efficient way to obtain bio-optical water quality parameters. Optimization of bio-optical models is done as local parameters change regionally and seasonally, thus requiring calibration. Field spectral measurements and in-situ water quality data taken during simultaneous satellite overpass were used to calibrate the bio-optical modelling tool WASI-2D to get estimates of chlorophyll-a concentration from the corresponding Landsat-8 images. The initial output values for chlorophyll-a concentration, which ranges from 10–40 μg/L, has an RMSE of up to 10 μg/L when compared with in situ data. Further refinements in the initial and constant parameters of the model resulted in an improved chlorophyll-a concentration retrieval from the Landsat-8 images. The outputs provided a chlorophyll-a concentration range from 5–12 μg/L, well within the usual range of measured values in the lake, with an RMSE of 2.28 μg/L compared to in situ data.