The University of Arizona

Evaluating Existing and Developing New Drought Indices Using Modeled Soil Moisture Time Series | CLIMAS

Evaluating Existing and Developing New Drought Indices Using Modeled Soil Moisture Time Series

Evaluating Existing and Developing New Drought Indices Using Modeled Soil Moisture Time Series

CLIMAS Lead:  

Stakeholders across the Southwest have struggled to utilize existing drought indices because of their failure to capture the unique seasonality and complex hydroclimate of the region. Soil moisture is a key drought indicator that is not well represented in existing drought indices, and deficits in soil moisture are difficult to measure directly, as there are few existing monitoring sites and even fewer historical time series to analyze. To understand the relative roles of changing precipitation and temperature regimes on soil moisture, we will model historical time series of soil moisture at numerous stations across Arizona and New Mexico using a soil water model (HYDRUS 1-D). These time series will be integrated into an analysis of the role of hydroclimatic variability and temperature in controlling drought intensity and frequency in the semi-arid climate of the Southwest, and  compared with traditional drought monitoring indices to identify strengths and weaknesses for capturing soil moisture, and to establish drought monitoring best practices.

Central Question: What are the relative roles of changing precipitation regimes and temperatures in the historical variability of soil moisture in Arizona and New Mexico and what drought indices best capture this variability?