TY - JOUR
T1 - Development of WTI and turbidity estimation model using SMA - Application to Kushiro Mire, eastern Hokkaido, Japan
AU - Kameyama, Satoshi
AU - Yamagata, Yoshiki
AU - Nakamura, Futoshi
AU - Kaneko, Masami
N1 - Funding Information:
The authors thank Dr. Masayuki Tamura and Hiroyuki Oguma at the National Institute of Environmental Science for providing the Field Spec spectrometer used in this study. Dr. Touru Araya, Professor of Hokkaido University, Faculty of Agriculture, provided useful advice on the research design. Stefan Hotes, a student in the Department of Environmental Science in Hokkaido University, gave us comprehensive knowledge on wetland vegetation and its dynamics. Saiha Jennifer Sung, a staff of a Japanese Conservation Organization (EnVision), provided helpful suggestions for the manuscript. The funding for this work was provided by Grant-in-Aid for Scientific Research (07456065,10460059) from the Ministry of Education, Science and Culture.
PY - 2001
Y1 - 2001
N2 - A new water-turbidity index (WTI) based on multispectral images was developed and tested at Kushiro Mire, eastern Hokkaido, Japan. An algorithm for turbidity estimation was developed and applied to Landsat TM images to monitor the turbid water on the mire surface during the snow-melting season. We used spectral mixture analysis (SMA) to produce a turbidity estimation model. The SMA "unmixes" a mixed pixel determining the fractions due to each spectral end member. In this study, we used four end members (1, alder; 2, reed; 3, high-concentration turbid water (485 ppm); 4, low-concentration turbid water (10 ppm) measured in the test site. The WTI was determined by the following equation: WTI = amax/(amax+ amin) where amax is abundance of high-concentration turbid water and amin is abundance of low-concentration turbid water. The end-member spectra of alder and reed were measured in the laboratory using specimens collected at the test site. The spectrum of turbid water was measured at the test sites. The relative abundance of each end member was estimated based on this spectral information using SMA. The same formula was applied to Landsat TM images. Then we applied the WTI equation to the end-member images to obtain a WTI map. In the mire wetland region, turbid water spreads under alder trees and reed grasses. To verify our turbidity estimation method based on WTI under these conditions, we constructed a small experimental wetland consisting of mixed stands of alder and reed. WTI was calculated from the mixed spectrum of this "artificial wetland" and the regression curve for the relation between WTI and the actual turbidity was determined (R2=.91). Finally, this regression equation was used to derive a turbidity map from the WTI image.
AB - A new water-turbidity index (WTI) based on multispectral images was developed and tested at Kushiro Mire, eastern Hokkaido, Japan. An algorithm for turbidity estimation was developed and applied to Landsat TM images to monitor the turbid water on the mire surface during the snow-melting season. We used spectral mixture analysis (SMA) to produce a turbidity estimation model. The SMA "unmixes" a mixed pixel determining the fractions due to each spectral end member. In this study, we used four end members (1, alder; 2, reed; 3, high-concentration turbid water (485 ppm); 4, low-concentration turbid water (10 ppm) measured in the test site. The WTI was determined by the following equation: WTI = amax/(amax+ amin) where amax is abundance of high-concentration turbid water and amin is abundance of low-concentration turbid water. The end-member spectra of alder and reed were measured in the laboratory using specimens collected at the test site. The spectrum of turbid water was measured at the test sites. The relative abundance of each end member was estimated based on this spectral information using SMA. The same formula was applied to Landsat TM images. Then we applied the WTI equation to the end-member images to obtain a WTI map. In the mire wetland region, turbid water spreads under alder trees and reed grasses. To verify our turbidity estimation method based on WTI under these conditions, we constructed a small experimental wetland consisting of mixed stands of alder and reed. WTI was calculated from the mixed spectrum of this "artificial wetland" and the regression curve for the relation between WTI and the actual turbidity was determined (R2=.91). Finally, this regression equation was used to derive a turbidity map from the WTI image.
KW - Kushiro Mire
KW - Spectral mixture analysis
KW - Turbidity estimation
KW - Water-turbidity index
KW - Wetland management
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U2 - 10.1016/S0034-4257(01)00189-4
DO - 10.1016/S0034-4257(01)00189-4
M3 - Article
AN - SCOPUS:0034924935
VL - 77
SP - 1
EP - 9
JO - Remote Sensing of Environment
JF - Remote Sensing of Environment
SN - 0034-4257
IS - 1
ER -