Hawaii 1990-2019 gridded monthly rainfall mm

This dataset contains gridded monthly rainfall from 1990 to 2019 at 250 m resolution for seven of the eight main Hawaiian Islands (18.849°N, 154.668°W to 22.269°N, 159.816°W; the island of Ni‘ihau is excluded due to lack of data). The gridded data use a World Geographic Coordinate System 1984 (WGS84) and are stored as individual GeoTIFF files for each month-year, as indicated by the GeoTIFF file name. Contained in the dataset is a statewide complete 30-year partially gap filled monthly rainfall dataset for all stations for the entire date range with station names, ID and location. Also included are month year statewide files for rainfall kriging input files which contain station rainfall, station rainfall transformations, station transformed anomaly, and denotation of inclusion in per county kriging process, statewide gridded rainfall, statewide standard error, statewide gridded rainfall anomaly, statewide gridded rainfall anomaly standard errors, and statewide meta-data that contain per county as well as statewide cross validation statistics, station counts, and readable data quality statement. Monthly rainfall grids were created using an optimized geostatistical kriging approach to interpolate relative rainfall anomalies which are then combined with long-term means to develop the climatologically aided gridded estimates. Optimization of the kriging algorithm consists of: 1) determining an offset (constant) to use when log-transforming data; 2) quality controlling data prior to interpolation; 3) using machine learning to detect erroneous maps; and 4) identifying the most appropriate parametrization scheme for fitting the model used in the interpolation. At present, the data are available from 1990 to 2019, but datasets will be updated as new gridded monthly rainfall data become available. Rainfall products and error metrics are also available by county and can be accessed online for easy download through the Hawaiʻi Data Climate Portal available at http://www.hawaii.edu/climate-data-portal.