Frequency characteristics of soil moisture, evapotranspiration, and climatic water deficit for Kauaʻi for historical and future drought conditions, and 2020 land cover

This shapefile represents the frequency characteristics of soil moisture, evapotranspiration, and climatic water deficit for Kauaʻi, Hawaiʻi for four water-budget scenarios. The four scenarios include (1) historical non-drought rainfall and 2020 land cover, (2) historical drought rainfall and 2020 land cover, (3) future non-drought rainfall and 2020 land cover, and (4) future drought rainfall and 2020 land cover. Historical non-drought rainfall is monthly rainfall during 1990–97 and 2003–06 from Frazier and others (2016). Historical drought rainfall is monthly rainfall during 1998–2002 and 2007–12 from Frazier and others (2016). Future non-drought rainfall is monthly rainfall during 1990–97 and 2003–06 from Frazier and others (2016) adjusted for a Representative Concentration Pathway 8.5 2071–99 (RCP8.5 2071–99) projection from Elison Timm and others (2015). Future drought rainfall is monthly rainfall during 1998–2002 and 2007–12 from Frazier and others (2016) adjusted for a RCP8.5 2071–99 projection from Elison Timm and others (2015). Monthly rainfall for historical and future non-drought conditions was disaggregated into daily values using daily rainfall during 1990–97 and 2003–06 from Longman and others (2019). Monthly rainfall for historical and future drought conditions was disaggregated into daily values using daily rainfall during 1998–2002 and 2007–12 from Longman and others (2019). A 2020 land-cover map developed by Kāne and others (2024a, 2024b) was used to define the land-cover conditions and the model subareas. 
Monthly time series estimates of soil moisture, evapotranspiration, and climatic water deficit for each model subarea were computed for each scenario using a water-budget model developed by Oki (2022). Monthly time series estimates of soil moisture, evapotranspiration, and climatic water deficit were used to compute the relative frequency for each model subarea for selected moisture-stress levels, where relative frequency describes the decimal fraction of months that soil moisture or evapotranspiration is less than or equal to (or climatic water deficit is greater than or equal to) the selected moisture-stress levels. A value of 0.074 was selected as the moisture-stress level for monthly mean soil moisture, expressed as a fraction of available water capacity. A value of 0.96 inches was selected as the moisture-stress level for monthly evapotranspiration. Climatic water deficit is defined as the evaporative demand that exceeds available water and is calculated as the difference between potential evapotranspiration and evapotranspiration. A value of 0.77 was selected for monthly climatic water deficit, expressed as a fraction of potential evapotranspiration. 
The shapefile attribute information associated with each subarea present an estimate of the relative frequency of soil moisture, evapotranspiration, and climatic water deficit for each drought scenario, and select geographic and land-cover attributes. Brief descriptions of the relative frequencies and other attributes are included in this metadata file. Refer to Mair and others (2024) for further details of the methods and sources used to select the moisture-stress levels and determine the relative frequencies of soil moisture, evapotranspiration, and climatic water deficit, and characterize the other attributes.

Tags: climatic-water-deficit, cloud-water-interception, droughts, effects-of-climate-change, evaporation, fires, kauai, land-use-and-land-cover, pacific-islands, soil-moisture, state-of-hawaii, transpiration, usgs-648904bcd34ef77fcafe4481, water-budget, water-budget-model, water-cycle
Organization: Department of the Interior