Mapping of diffuse attenuation coefficient in optically complex waters of amazon floodplain lakes

Author(s)

Maciel, Daniel Andrade ^[1] ; Faria Barbosa, Claudio Clemente ^[2] ; Leao de Moraes Novo, Evlyn Marcia ^[2] ; Cherukuru, Nagur ^[3] ; Martins, Vitor Souza ^[4] ; Flores Junior, Rogerio ^[2] ; Jorge, Daniel Schaffer ^[5] ; Sander de Carvalho, Lino Augusto ^[6] ; Carlos, Felipe Menino ^[7]

Affiliation

^[1] Natl Inst Space Res INPE, Grad Div, Remote Sensing Program, BR-12227010 Sao Jose Dos Campos, SP - Brazil

^[2] Natl Inst Space Res INPE, Earth Observat & Geoinformat Div, BR-12227010 Sao Jose Dos Campos, SP - Brazil

^[3] CSIRO Oceans & Atmosphere, Canberra, ACT - Australia

^[4] Michigan State Univ, Ctr Global Change & Earth Observat, E Lansing, MI 48824 - USA

^[5] Univ Littoral Cote dOpale, Univ Lille, UMR 8187, CNRS, LOG Lab Oceanol & Geosci, F-62930 Wimereux - France

^[6] Fed Univ Rio de Janeiro UFRJ, Dept Meteorol, BR-21941916 Rio De Janeiro - Brazil

^[7] Natl Inst Space Res INPE, Grad Div, Comp Sci Program, BR-12227010 Sao Jose Dos Campos, SP - Brazil

• Document type: Journal article
• Source: ISPRS JOURNAL OF PHOTOGRAMMETRY AND REMOTE SENSING; v. 170, p. 72-87, DEC 2020.
• Web of Science Citations: 0

Abstract

The modeling of underwater light field is essential for the understanding of biogeochemical processes, such as photosynthesis, carbon fluxes, and sediment transports in inland waters. Water-column light attenuation can be quantified by the diffuse attenuation coefficient of the downwelling irradiance (K-d) using semi-analytical algorithms (SAA). However, the accuracy of these algorithms is currently limited in highly turbid environments, such as Amazon Floodplains, due to the SAA parametrization steps. In this study, we assessed an SAA approach for K-d retrieval using a sizeable (n = 239) and diverse dataset (e.g., K-d (490) ranging from almost 0 to up to 30 m(-1) with mean values of 5.75 +/- 3.94 m(-1)) in Amazon freshwater ecosystem. The main framework of this study consists of i) re-parametrization of a quasi-analytical algorithm using regional in-situ inherent optical properties (IOPs) and ii) application and validation of SAA for K-d retrieval using in-situ and Sentinel-2/MSI (n = 49) derived from Remote Sensing Reflectance (R-IS). Overall, the performance of the calibrated SAA was satisfactory for both in-situ and satellite R-rs. The validation results with in-situ data achieved a Mean Absolute Percentage Error (MAPE) lower than 22%, Correlation Coefficient (R) > 0.80, Root Mean Square Error (RMSE) lower than 1.7 m(-1) and bias between 0.73 and 1.34 for simulated visible bands of Sentinel-2/MSI (490, 560 and 660 nm) (VIS). The results using MSI imagery were similar to those of in-situ, with R > 0.9, MAPE < 20%, RMSE < 1.25 m(-1), and bias between 0.98 and 1.10 for VIS bands, which illustrate the viability of this methodology for K-d mapping in Amazon Floodplain Lakes. Therefore, this study demonstrates a successful application of satellite remote sensing data for the spatialization of the K-d in the optically complex waters of Amazon Basin, which is essential for the ecological management of the Amazon Floodplain Lakes. (AU)

• FAPESP's process: 14/23903-9 - Bio-optical spatio-temporal characterization and development of analytical algorithms for the systematic monitoring of water masses circulating on the floodplain of medium and lower Amazon
• Grantee: Cláudio Clemente Faria Barbosa
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/12083-1 - Balancing biodiversity conservation with development in Amazon wetlands - bonds
• Grantee: Evlyn Márcia Leão de Moraes Novo
• Support Opportunities: Regular Research Grants