Abstract ID: 224
Interseasonal terrestrial-atmospheric drivers of flash drought over Europe
Lead Author: Daniel Mesheske
Department of Civil Engineering and Environmental Science – University of Oklahoma, United States of America
Keywords: Flash Drought, Drought Prediction, Soil Moisture, Evaporation, Climate Change
Abstract: Anthropogenic climate change is expected to increase the frequency and intensity of climactic extremes across Europe. With rising temperatures, the impacts of a severe or prolonged agricultural drought could yield devastating financial costs. As such, indicators that predict future flash drought could mitigate risk and damage. Currently, climate prediction models are showing moderate success with droughts at a shorter temporal scale but, seasonal to sub-seasonal prediction skill is less accurate. Lack of precipitation is often used as the main driving factor of drought development; however, rapid drought development is often a combination of many atmospheric and surface state variables. This study explores the seasonal and inter-seasonal relationships between atmospheric and land surface variables using linear regression and correlation analysis. Data from MERRA-2, between 1980 and 2020, were used for temperature, ET, PET, and soil moisture. ET and PET were used to derive the Standardized Evaporative Stress Ratio (SESR), which is a metric that incorporates several near-surface state variables to represent evaporative stress on the environment. It is shown through regression modeling that higher mean temperatures lead to increased evaporative stress and reduced root zone soil moisture throughout much of Europe during spring, summer, and fall. Correlation values yielded a strong negative relationship consistent with the known characteristics between temperature, evaporative stress, and soil moisture. Further, lag-regression analysis between subsequent seasons demonstrated strong negative correlations for mean temperature and mean SESR ratio for both a spring-summer and summer-fall seasonal lag across much of the European continent. In addition, many of these correlations show statistical significance above 90%. A similar relationship between root zone soil moisture with temperature and SESR also yielded correlation at elevated levels of statistical significance across the continent. Finally, examination of 3 major European flash drought events shows regional high temperature anomalies in the preceding season. These findings indicate that springtime temperature may be a critical precursor to growing season flash drought development.
Jeff Basara (School of Meteorology, Department of Civil Engineering and Environmental Science – University of Oklahoma)
Jordan Christian (School of Meteorology – University of Oklahoma)