The GRQA contains the CSV files for processed observation data (*_GRQA.csv) along with corresponding metadata (observation site information, etc) for 42 different water quality parameters.

In addition to the observation data, ZIP files containing additional metadata, figures and GRQA source datasets are provided.

The GRQA_meta.zip file contains the following files:
List of parameter codes in GRQA used for looping over during parallel processing (GRQA_param_codes.txt)
Potential duplicate observation sites per parameter (*_dup_obs.csv)
Basic statistics of GRQA observation time series per parameter (GRQA_param_stats.csv)

An overview of all 42 parameters in the form of statistical figures is given in the data catalog document (GRQA_data_catalog.pdf).

The figures shown in the data catalog are also included in the file GRQA_figures.zip for each parameter:
Map of spatial distribution of observation sites per source dataset (*_spatial_dist.png)
Map of monthly availability of time series per site (*_availability.png)
Map of monthly continuity of time series per site (*_continuity.png)
Map of median observation values per site (*_median.png)
Temporal distribution plot of observations per source dataset (*_temporal_hist.png)
Histogram of observation values per source dataset (*_hist.png)
Box plot of observation values per source dataset (*_box.png)

Additional grid plots (GRQA_*_grid.png) of each of the aforementioned seven plot types showing DO, DOC, TP and TSS were created to be included in the scientific paper describing GRQA.

In addition, the file GRQA_source_data.zip containing the five source datasets (CESI, GEMSTAT, GLORICH, WATERBASE and WQP) along with metadata and statistics collected from both raw and processed data is given.

The raw/meta folder in each of the source data subfolders contains the following files:
Lookup tables used for harmonizing the parameters and units (*_code_map.csv, WQP_code_map.txt)
Unit files for sources with multiple units per parameter (*_units.csv)
Remark code lookup for GLORICH (GLORICH_remark_codes.csv)
US state codes used for downloading WQP temperature data (fips_state.csv)

The processed/meta folder in each of the source_data subfolders contains the following files:
Number of missing values in source file columns (*_missing_values.csv)
Source file size and row count information (*_file_info.csv)
Observation data statistics per parameter before harmonization (*_raw_stats.csv)
Observation data statistics per parameter after harmonization (*_processed_stats.csv)
Duplicate site IDs in source data (*_dup_sites.csv)

Scripts used for the creation of GRQA are found on Zenodo at https://doi.org/10.5281/zenodo.5082147