POSTER SESSION 4
10:30–12:30, Thursday, September 17
Poster Session | 1 | 2 | 3 | 4 | Schedule at a Glance
ABSTRACT 1245 | POSTER 4
FROM IN SITU TO SATELLITE: EVALUATING THE TRANSFERABILITY OF BIO-OPTICAL RELATIONSHIPS FOR IOP RETRIEVAL IN TROPICAL COASTAL WATERS
Retrieval of inherent optical properties (IOPs) from satellite data remains a challenge in optically complex coastal waters. This study evaluates the transferability of bio-optical relationships for estimating IOPs using five reflectance representations: in situ hyperspectral Rrs, in situ Rrs resampled to PRISMA and Sentinel-2 (S2) band configurations, and Rrs extracted direclty from PRISMA and S2 satellite imagery. Rrs and phytoplankton absorption, non-algal particle absorption, colored dissolved organic matter absorption (aCDOM), and chlorophyll-a (Chl-a), were collected in the Costa dos Corais Environmental Protection Area, Alagoas, Brazil, in December 2022. For each Rrs source, an independent full-spectral search identified the optimal single-band and band-ratio predictors for each IOP, allowing each source to achieve its best possible retrieval performance. Band-ratio models consistently outperformed single-band approaches, with aCDOM improving from R²=0.481 (single band at 727 nm) to R²=0.965 using Rrs(625)/Rrs(585). Results reveal a two-stage degradation in IOP retrieval performance: spectral resampling of in situ Rrs leads to moderate accuracy loss, whereas extracting Rrs from satellite imagery causes a sharp accuracy decline. aCDOM degraded from R²=0.965 to 0.102 and 0.066, and Chl-a from R²=0.884 to 0.747 and 0.062, for in situ, PRISMA and S2 imagery, respectively. Cross-validation confirmed robust in situ relationships for aCDOM (R²_cv = 0.929) and Chl-a (R²_cv = 0.807). These findings suggest that the primary limitation in IOP retrieval is not spectral resolution, but the degradation of satellite-derived reflectance and spatial heterogeneity at the pixel scale, highlighting the critical role of atmospheric correction in coastal waters.
Thais Andrade Galvao de Medeiros, National Institute For Space Research (INPE), Brazil, [email protected], https://orcid.org/0000-0002-5583-4788
Julia Caon Araujo, Federal University of Rio de Janeiro, [email protected], https://orcid.org/0000-0003-3492-3658
José Carlos Sícoli Seoane, Federal University of Rio de Janeiro, [email protected], https://orcid.org/0000-0001-7728-3764
Milton Kampel, National Institute For Space Research (INPE), [email protected], https://orcid.org/0000-0002-0011-2083
Vittorio Brando, Consiglio Nazionale delle Ricerche, [email protected], https://orcid.org/0000-0002-2193-5695
Maria Laura Zoffoli, Consiglio Nazionale delle Ricerche, [email protected], https://orcid.org/0000-0003-1892-0051
Poster Session | 1 | 2 | 3 | 4 | Schedule at a Glance
