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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Performance Analysis of MODIS 500-m Spatial Resolution Products for Estimating Chlorophyll-a Concentrations in Oligo-to Meso-Trophic Waters Case Study: Itumbiara Reservoir, Brazil

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Author(s):
Ogashawara, Igor [1] ; Alcantara, Enner H. [2] ; Curtarelli, Marcelo P. [1] ; Adami, Marcos [3] ; Nascimento, Renata F. F. [4] ; Souza, Arley F. [5] ; Stech, Jose L. [1] ; Kampel, Milton [1]
Total Authors: 8
Affiliation:
[1] Natl Inst Space Res INPE, Remote Sensing Div, BR-1758 Sao Jose Dos Campos, SP - Brazil
[2] State Univ Sao Paulo, Cartog Engn Dept, BR-19060900 Prudente, SP - Brazil
[3] Natl Inst Space Res INPE, Reg Ctr Amazon, BR-2651 Belem, PA - Brazil
[4] Geopixel Solucoes Geotecnol, BR-12245902 Sao Jose Dos Campos, SP - Brazil
[5] ETEP Fac, BR-12242800 Sao Jose Dos Campos, SP - Brazil
Total Affiliations: 5
Document type: Journal article
Source: REMOTE SENSING; v. 6, n. 2, p. 1634-1653, FEB 2014.
Web of Science Citations: 8
Abstract

Monitoring chlorophyll-a (chl-a) concentrations is important for the management of water quality, because it is a good indicator of the eutrophication level in an aquatic system. Thus, our main purpose was to develop an alternative technique to monitor chl-a in time and space through remote sensing techniques. However, one of the limitations of remote sensing is the resolution. To achieve a high temporal resolution and medium space resolution, we used the Moderate Resolution Imaging Spectroradiometer (MODIS) 500-m reflectance product, MOD09GA, and limnological parameters from the Itumbiara Reservoir. With these data, an empirical (O14a) and semi-empirical (O14b) algorithm were developed. Algorithms were cross-calibrated and validated using three datasets: one for each campaign and a third consisting of a combination of the two individual campaigns. Algorithm O14a produced the best validation with a root mean square error (RMSE) of 30.4%, whereas O14b produced an RMSE of 32.41% using the mixed dataset calibration. O14a was applied to MOD09GA to build a time series for the reservoir for the year of 2009. The time-series analysis revealed that there were occurrences of algal blooms in the summer that were likely related to the additional input of nutrients caused by rainfall runoff. During the winter, however, the few observed algal blooms events were related to periods of atmospheric meteorological variations that represented an enhanced external influence on the processes of mixing and stratification of the water column. Finally, the use of remote sensing techniques can be an important tool for policy makers, environmental managers and the scientific community with which to monitor water quality. (AU)

FAPESP's process: 07/08103-2 - Study of circulation, water quality and land use in the Itumbiara Reservoir hydrographic basin
Grantee:José Luiz Stech
Support Opportunities: Regular Research Grants