| Full text | |
| Author(s): |
Evlyn Márcia Leão de Moraes Novo
[1]
;
Luciana de Resende Londe
[2]
;
Claudio Barbosa
[3]
;
Carlos A. S. de Araujo
[4]
;
Camilo Daleles Rennó
[5]
Total Authors: 5
|
| Affiliation: | [1] Instituto Nacional de Pesquisas Espaciais - Brasil
[2] Centro Nacional de Monitoramento e Alertas de Desastres Naturais - Brasil
[3] Instituto Nacional de Pesquisas Espaciais - Brasil
[4] Instituto Nacional de Pesquisas Espaciais - Brasil
[5] Instituto Nacional de Pesquisas Espaciais - Brasil
Total Affiliations: 5
|
| Document type: | Journal article |
| Source: | Rev. Ambient. Água; v. 8, n. 3, p. 65-82, 2013-12-00. |
| Abstract | |
This work proposes a trophic state index based on the remote sensing retrieval of chlorophyll-α concentration. For that, in situ Bidirectional Reflectance Factor (BRF) data acquired in the Ibitinga reservoir were resampled to match Landsat/TM spectral simulated bands (TM_sim bands) and used to run linear correlation with concurrent measurements of chlorophyll-α concentration. Monte Carlo simulation was then applied to select the most suitable model relating chlorophyll-α concentration and simulated TM/Landsat reflectance. TM4_sim/TM3_sim ratio provided the best model with a R² value of 0.78. The model was then inverted to create a look-up-table (LUT) relating TM4_sim/TM3_sim ratio intervals to chlorophyll-α concentration trophic state classes covering the entire range measured in the reservoir. Atmospheric corrected Landsat TM images converted to surface reflectance were then used to generate a TM4/TM3 ratio image. The ratio image frequency distribution encompassed the range of TM4_sim/TM3_sim ratio indicating agreement between in situ and satellite data and supporting the use of satellite data to map chlorophyll-α concentration trophic state distribution in the reservoir. Based on that, the LUT was applied to a Landsat/TM ratio image to map the spatial distribution of chlorophyll-α trophic state classes in Ibitinga reservoir. Despite the stochastic selection of TM4_sim/TM3_sim ratio as the best input variable for modeling the chlorophyll-α concentration, it has a physical basis: high concentration of phytoplankton increases the reflectance in the near-infrared (TM4) and decreases the reflectance in the red (TM3). The band ratio, therefore, enhances the relationship between chlorophyll-α concentration and remotely sensed reflectance. (AU) | |
| FAPESP's process: | 08/56252-0 - Environmental and socioeconomic impacts associated with the production and consumption of sugarcane ethanol in south central Brazil |
| Grantee: | Evlyn Márcia Leão de Moraes Novo |
| Support Opportunities: | Program for Research on Bioenergy (BIOEN) - Thematic Grants |
| FAPESP's process: | 04/15901-4 - Comportamento espectral de fitoplancton de aguas interiores do brasil. |
| Grantee: | Evlyn Márcia Leão de Moraes Novo |
| Support Opportunities: | Regular Research Grants |