ENVISAT MERIS Regional Mapped Inland Waters (ILW) Data, version 5.0

ILW delivers Rayleigh-corrected surface reflectance (ρs, unitless) and the Cyanobacteria Index (CI_cyano, unitless). The data target for MERIS and OLCI are 15,450 CONUS waterbodies (≥1 full-resolution 300 m OLCI pixel), >2,300 larger resolvable lakes (≥3 pixels), and 5,874 resolvable lakes in Alaska—created in collaboration with the CyAN program to reduce user processing and provide a standardized resource for inland-water algorithm development, validation, and trend analysis.

PACE OCI ILW targets 117 CONUS lakes (≥3 pixels) and lakes across Alaska. Geophysical variables in this suite include: - CI_cyano – Cyanobacteria Index, cyanobacteria only (Wynne & Stumpf algorithm, 2013) (sr⁻¹) - flags_habs – Harmful Algal Bloom flags (unitless / bitmask) - rhos_λ – Surface reflectance at wavelength λ (dimensionless)