NASA Earth eXchange Hawai'i downscaled climate projections CMIP6 (NEX-HIDCP-CMIP6) dataset

Hawai'i's complex topography, pronounced microclimates, and geographic isolation make coarse-scale global climate model output inadequate for local planning, and high-resolution climate projections tailored to the state have until now been lacking. To address this gap, we introduce the NASA Earth eXchange Hawai'i Downscaled Climate Projections CMIP6 (NEX-HIDCP-CMIP6), a new archive of downscaled historical and future climate projections based on output from Phase 6 of the Coupled Model Intercomparison Project (CMIP6) over the State of Hawai'i. The dataset covers the years 1950-2100 and includes three variables (maximum temperature, minimum temperature, and precipitation) from five CMIP6 experiments (the historical experiment and the four Tier 1 scenarios: SSP1.2-6, SSP2.4-5, SSP3.7-0, and SSP5.8-5) as available from thirty CMIP6 models. The downscaled products are provided at 250-meter horizontal resolution and daily temporal resolution and were generated using the daily Bias Correction Spatial Disaggregation (BCSD) method against previously published 250-meter gridded observations from the Hawai'i Climate Data Portal. Technical validation confirms that the downscaled fields reproduce the expected geographic distribution of temperature and precipitation, with ensemble-mean precipitation generally within ±2% of the gridded observations and temperature means within 0.04 °C. NEX-HIDCP-CMIP6 complements two other NEX products, NEX-GDDP-CMIP6 and NEX-DCP30-CMIP6, fills a critical geographic gap in downscaled climate products for the United States, and is freely available through the NASA Advanced Supercomputing Data Portal.