Soil moisture and ecosystem vegetation health effects on drought severity

Droughts are expected to become more severe due to climate disturbances, posing a serious risk to ecosystems. Therefore, quantifying the drought severity and the resilience of soil moisture and vegetation greening is essential for studying whether the local ecosystem is approaching an alternative state that may be dangerous for agriculture.

This study aimed to explore the interactions among vegetation, soil moisture, and drought severity to identify the sensitivity of grid cells to drought under maximum cumulative water deficit critical thresholds and the influence of adaptation factors.

Drought severity and climate disturbance in a local ecosystem were quantified using dynamically adjusted thresholds, a composite drought index, and a dimensionless index based on water-use efficiency.

Moderate and severe drought events were observed using only the drought index. However, these identified events differed across grid cells using the leaf area index representing vegetation health and soil moisture thresholds, suggesting less coverage of drought-affected areas. A substantially reduced drought severity event using adaptation factors showed that local climate and adaptation could significantly change these events.

These findings provide new insights into vegetation greening and soil moisture resilience in various regions under drought conditions. The adaptation factor approach significantly reduced the severity of drought tipping events, indicating that local climate and adaptation may affect drought tipping events.