- Drought represents an import part of natural hydrologic cycles that govern the rate and transportation of water on global and regional scales. (Trenberth, et al. 2015) Agriculturally, drought represents a threat to crop production and can endanger political and economic stability through the loss of resources and the threat of famine. (Sternberg, 2012) Ecosystem observations also indicate drought has a significant impact on biodiversity and productivity both of large-scale fauna and microbial communities. (Eisenhauer, et al., 2011) As the impacts of global climate change include an increased rate and severity of drought the need to gain a better understanding of drought mechanisms and patterns have also increased. This paper utilizes data from the National Center for Atmospheric Research’s (NCAR) self-calibrated Palmer Drought Severity Index (scPDSI), the University of Utah’s waterisotopes.org, and NASA’s Tropospheric Emission Spectrometer (TES) to investigate the impact of adding stable water isotopes to drought prediction models. Model accuracy is reported as the root-mean-squared-error (RMSE), and the impact of stable water isotopes are reported as percent improvement. The analysis included linear, support-vector, ridge, and least absolute shrinkage and selection operator regression across multiple years in three distinct hydrologic regimes: atmospheric water vapor, precipitation, and surface water (lakes, rivers, and streams). Stable water isotopes were shown to be useful at improving drought prediction, especially at a time lag of +1 month, and when the isotopes were collected from surface water. The level of improvement varied greatly, with some models showing that it actually made it worse, but overall indicated that using stable water isotopes may assist in addressing the complexity of trying to predict drought. Future research needs to address the lack of geographically diverse stable water isotope data in precipitation and surface water and should seek to compare scPDSI values on a smaller scale that can better take into account the impact of internal dynamics within a region of interest.
- Key Words: Drought, stable water isotopes, PDSI