Remote sensing of nutrients in a subtropical African reservoir: testing utility of Landsat 8 |
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| Authors: | Mhosisi Masocha Chipo Mungenge Tamuka Nhiwatiwa |
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| Institution: | 1. Faculty of Science, Department of Geography &2. Environmental Science, University of Zimbabwe, Harare, Zimbabwe;3. Faculty of Science, Department of Biological Sciences, University of Zimbabwe, Harare, Zimbabwe |
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| Abstract: | Remote sensing is useful for water quality assessments but current remote sensing applications favour parameters that are easy to detect such as chlorophyll-a. An assessment of the utility of Landsat 8 for detecting nutrients was conducted in Mazvikadei reservoir in Zimbabwe. The main objective was to determine whether nutrients often overlooked by remote sensing and yet are the main determinants of water quality can be remotely sensed. Sampling targeted ammonia, nitrates and reactive phosphorus from May to October 2015. In situ nutrient concentrations were regressed against reflectance derived from Landsat 8 imagery. Strong negative relationships were found between ammonia and the near-infrared band in July (R2 = 0.80, p < 0.05) as well as between nitrates and the blue band (R2 = 0.67, p < 0.05) in June. Overall, the results suggest that the cool dry season is the optimum time to use Landsat 8 for monitoring nutrients in tropical lakes. |
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| Keywords: | Ammonia lake monitoring nitrates reactive phosphorus water quality |
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