Flash drought events in Noah-MP model

This study investigates the ability of the Noah-MP model to simulate flash drought events, which are characterized by their rapid onset and severe impacts. Understanding flash droughts is critical due to their significant socio-economic and environmental consequences. The Noah-MP offline model is utilized due to its efficiency and robust representation of land surface processes. The model is driven by hourly ERA5 Reanalysis data from 1980 to 2020, covering the contiguous United States (CONUS). To measure flash drought events, the flash drought intensity index (FDII), which accounts for both the rapid intensity and severity of flash droughts, is applied. Additionally, experiments are conducted with and without dynamic vegetation to assess its impact on the simulation of flash drought events. Given that the occurrence and strength of flash droughts can vary depending on the drought monitoring datasets employed, we compare a variety of drought indices—including the Standardized Precipitation-Evapotranspiration Index (SPEI), the Evaporative Stress Index (ESI), and the Evaporative Demand Drought Index (EDDI)—to ensure a comprehensive assessment. This comparative analysis aims to elucidate the strengths and limitations of the model in replicating various aspects of flash drought dynamics. Our findings will contribute to a better understanding of the capabilities of the Noah-MP model in simulating flash droughts, ultimately aiding in the development of more accurate physical processes within the Noah-MP model.