Global Daily Satellite-Derived Lake Surface Water Quality Dataset (2002-2022)

This repository hosts a standardized, accessible dataset of concurrent daily water quality statistics for 5,551 lakes worldwide from 2002 to 2022. Derived from the European Space Agency's Lakes Climate Change Initiative (ESA Lakes_cci) v2.1 and intersected with HydroLAKES v1.0 polygon boundaries, the dataset provides lake-wide statistics (minimum, maximum, mean, standard deviation, valid pixel count, spatial coverage ratio) for three water quality parameters: chlorophyll-a (Chl-a, mg m⁻³), lake surface water temperature (LSWT, °C), and turbidity (NTU). Records are temporally harmonized to retain only days on which all three parameters are simultaneously valid. A multi-tiered QA/QC flagging scheme is included to identify spatial inhomogeneities and temporal anomalies. Repository contents: hylak_id_description.csv — 47-column summary metadata file (central coordinates, country, Köppen-Geiger climate zone, valid observation counts, and long-term monthly/year-round means) for all 5,551 lakes. hylak_id.zip — 5,551 individual CSV files (one per lake, named {hylak_id}.csv), each containing the 22-column daily time series with QA/QC flags. code.zip — Python (v3.10) scripts used for data extraction, spatial masking, zonal statistics, harmonization, and QA/QC flagging. Full methodology, variable definitions, and validation are described in the companion paper (DOI to be added after publication).