TAILIEUCHUNG - Developing algorithm for estimating chlorophyll-a concentration in the Thac Ba Reservoir surface water using Landsat 8 Imagery

This study aims at developing a regional algorithm to quantify chlorophyll-a concentration (Chla) in the Thac Ba Reservoir surface-water using Landsat 8 imagery basing on in-situ data of Chla and above-water reflectance taken in both dry and rainy seasons 2018. In situ datasets obtained from 30 water sampling sites show a strong correlation (R2=) with the reflectance ratio of two Landsat 8 (L8) bands, the green band (band 3: B3) versus the red band (band 4: B4), B3 / B4, by an exponential equation. | Vietnam Journal of Earth Sciences 41 1 10-20 Doi 0866-7187 41 1 13542 VAST Vietnam Academy of Science and Technology Vietnam Journal of Earth Sciences http jse Developing algorithm for estimating chlorophyll-a concentration in the Thac Ba Reservoir surface water using Landsat 8 Imagery Pham Quang Vinh1 2 Nguyen Thi Thu Ha3 Nguyen Thanh Binh1 Nguyen Ngoe Thang1 La Thi Oanh4 Nguyen Thien Phuong Thao4 1 Institute of Geography VAST 2Faculty of Geography Graduate University of Science and Technology 3Faculty of Geology VNU University of Science 4Sea and Island Research Center VNU University of Science Received 13 September 2018 Received in revised form 11 November 2018 Accepted 9 January 2019 ABSTRACT This study aims at developing a regional algorithm to quantify chlorophyll-a concentration Chia in the Thac Ba Reservoir surface-water using Landsat 8 imagery basing on in-situ data of Chia and above-water reflectance taken in both dry and rainy seasons 2018. In situ datasets obtained from 30 water sampling sites show a strong correlation R2 with the reflectance ratio of two Landsat 8 L8 bands the green band band 3 B3 versus the red band band 4 B4 B3 B4 by an exponential equation. The algorithm for estimating Chia using this ratio was well-matched up the validation using multiple-dates in-situ datasets R2 RMSE 5 and was then applied to L8 images level 2 acquired in both dry and rainy seasons to understand the spatiotemporal distribution of Chia over the reservofr. Obtained maps of Chia present clearly two trends 1 Chia in the reservoir water in the dry season averaged at mg m3 is relatively lower than those in the rainy season averaged at mg m3 2 In both seasons Chia increased from water area in front of the Chay River mouth to the center of the reservoir. The algorithm and method outlined in this study could be applied to monitoring Chi in other inland waters having similar features as the Thac Ba Reservofr water. .

• Địa Lý
• Vietnam journal of earth sciences
• Developing algorithm for estimating chlorophyll a concentration
• The Thac Ba Reservoir surface water using Landsat 8 Imagery
• Estimating chlorophyll a concentration
• Landsat 8 Imagery
• Quantify chlorophyll a concentration
• General characteristics of rare earth
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