Work

Flash Drought Characteristics Based on Three Identification Methods in the North China Plain, China

Year: 2026

Type: article

Abstract: Flash drought (FD) is a rapid onset and intense drought threatening ecology, the economy, and agriculture. The North China Plain (NCP) suffers from frequent droughts and limited water resources. This study proposed a new FD identification method, termed the mean-scaled evaporative stress ratio (MESR), to identify FD events in the NCP from 1981 to 2022. This method applied an improved standardized evaporative stress ratio (SESR) framework to identify FD by atmospheric evaporative demand. Combining root-zone soil moisture (RZSM), SESR, and MESR, FD spatiotemporal characteristics were explored from agricultural and land–atmosphere perspectives. A percentile-based FD hotspot indicator integrating FD characteristics was introduced to identify FD hotspots. The threshold sensitivity for FD identification was evaluated across different FD methods. Results show that FD frequency is high in the north-central NCP and low in the southern NCP. The onset and recovery stages, total duration, and severity all increase with RZSM-based FD intensity grades. However, FDs based on SESR and MESR have shorter onset stages but longer recovery stages as the FD intensity grade increases. By the joint influence of climate factors and human activities, FD characteristics show a decreasing trend temporally and spatially. Two FD hotspots with frequent, severe, and intense FDs are in the northeastern and southwestern NCP. Furthermore, FD frequency is significantly influenced by thresholds, and RZSM-based FD frequency decreases with increasing soil depth. Besides, compared to thresholds on decreasing indices, thresholds about pentads are sensitive to FD identification. This study improves the understanding of FD in the NCP, providing valuable insights for regional FD adaptation. Significance Statement Flash drought (FD) can harm the terrestrial ecosystem and cause great economic and agricultural losses. This study proposed a new FD identification method, termed the mean-scaled evaporative stress ratio (MESR), based on the standardized evaporative stress ratio (SESR), which utilizes the identification criteria similar to the SESR-based FD identification method but applies multiple probability density functions (PDFs) for MESR fitting and variable thresholds for MESR-based FD identification. The FD events in the North China Plain (NCP) from 1981 to 2022 were characterized using root-zone soil moisture (RZSM), SESR, and MESR from agricultural and land–atmosphere perspectives. A percentile-based FD hotspot indicator integrating FD characteristics was introduced in this study to determine FD hotspots in the NCP. The impact of thresholds on FD identification was quantified, and the thresholds display a great influence on FD frequency. This study provides valuable insights into the understanding of FD in the NCP.

Source: Journal of Climate

DOI: 10.1175/jcli-d-25-0314.1

Authors: Siyao Zhang, Keke Zhou, Jianzhu Li, Ting Zhang, Ping Feng

Institutions: Tianjin University, Ministry of Water Resources of the People's Republic of China

Language: English

Topic: Hydrology and Drought Analysis

Subfield: Global and Planetary Change

Field: Environmental Science

Domain: Physical Sciences

SDGs: Climate action, Clean water and sanitation, Zero hunger

Open Access status: bronze

Funder: National Natural Science Foundation of China