Monitoring water quality in a hypereutrophic reservoir using Landsat ETM+ and OLI sensors: how transferable are the water quality algorithms?
The launch of the Landsat 8 in February 2013 extended the life of the Landsat program to over 40 years, increasing the value of using Landsat to monitor long-term changes in the water quality of small lakes and reservoirs, particularly in poorly monitored freshwater systems. Landsat-based water quality hindcasting often incorporate several Landsat sensors in an effort to increase the temporal range of observations; yet the transferability of water quality algorithms across sensors remains poorly examined. In this study, several empirical algorithms were developed to quantify chlorophyll-a, total suspended matter (TSM), and Secchi disk depth (SDD) from surface reflectance measured by Landsat 7 ETM+ and Landsat 8 OLI sensors. Sensor-specific multiple linear regression models were developed by correlating in situ water quality measurements collected from a semi-arid eutrophic reservoir with band ratios from Landsat ETM+ and OLI sensors, along with ancillary data (water temperature and seasonality) representing ecological patterns in algae growth. Overall, ETM+-based models outperformed (adjusted R2 chlorophyll-a = 0.70, TSM = 0.81, SDD = 0.81) their OLI counterparts (adjusted R2 chlorophyll-a = 0.50, TSM = 0.58, SDD = 0.63). Inter-sensor differences were most apparent for algorithms utilizing the Blue spectral band. The inclusion of water temperature and seasonality improved the power of TSM and SDD models.
['Deutsch|Eliza S|ES|', 'Alameddine|Ibrahim|I|http://orcid.org/0000-0002-8974-1985', 'El-Fadel|Mutasem|M|']
D000465:Algorithms D002734:Chlorophyll D000077194:Chlorophyll A D004784:Environmental Monitoring D005068:Eutrophication D005618:Fresh Water D007861:Lebanon D010865:Pilot Projects D012044:Regression Analysis D058998:Remote Sensing Technology D012621:Seasons D014876:Water Pollution D060753:Water Quality
OLI Chlorophyll-a TSM SDD ETM + Landsat-7 Landsat-8 Qaraoun reservoir Type-II waters