Zhang et al. (2025) Concurrent occurrence of droughts and floods between the upper Hanjiang river and Northern North China at multi-temporal scales: an association with Arctic Oscillation

Identification

• Journal: Climate Dynamics
• Year: 2025
• Date: 2025-12-19
• Authors: Xiaodan Zhang, Guoyu Ren, Yuda Yang
• DOI: 10.1007/s00382-025-08006-x

Research Groups

• College of Geography and Planning, Chengdu University of Technology, China
• Center for Chinese Historical Geographical Studies, Fudan University, China
• Department of Atmospheric Science, School of Environmental Studies, China University of Geosciences, China
• National Climate Center, China Meteorological Administration, China

Short Summary

This study investigates the teleconnection between the warm-season Arctic Oscillation (AO) and concurrent drought and flood (DF) occurrences in the Upper Hanjiang River (UH) and Northern North China (NNC) from 1650 to 1975. It finds that DF in both regions largely varies in the same direction as the AO, with the AO serving as a significant predictor for DF, particularly on multi-decadal scales.

Objective

• To analyze the teleconnection between the warm-season Arctic Oscillation (AO) and drought and flood (DF) variability in the Upper Hanjiang River (UH) and Northern North China (NNC) at multi-temporal scales (inter-annual, inter-decadal, multi-decadal) from 1650 to 1975.

Study Configuration

• Spatial Scale: Upper Hanjiang River (UH) basin (95,200 km²) and Northern North China (NNC), including specific sites like Hanzhong, Ankang, Yunxi (UH) and Beijing, Tangshan, Tianjin, Baoding, Shijiazhuang, Cangzhou (NNC).
• Temporal Scale: 1650 to 1975, examining inter-annual (3–6 years), inter-decadal (around 12 years), and multi-decadal (around 20–30 years) scales.

Methodology and Data

• Models used:
  • Sliding average method (low-pass filter)
  • One-dimensional linear regression analysis
  • Empirical Orthogonal Function (EOF) analysis
  • Ensemble Empirical Mode Decomposition (EEMD)
  • Granger Causality Test (GCT)
  • Mann-Kendall (M-K) test
• Data sources:
  • Drought and Flood Grade (DFG) series (1650–1975) for UH and NNC: Reconstructed from historical records (local chronicles, Qing Dynasty archives, diaries, newspapers, magazines) and instrumental precipitation data (1951–1975) from the China National Surface Meteorological Station Homogenized Precipitation Data Set (V1.0).
  • Warm season (April–September) Arctic Oscillation (AO) index (1650–1975): Reconstructed from tree-ring chronologies (D’Arrigo et al. 2003).

Main Results

• Drought and flood (DF) variations in both the Upper Hanjiang River (UH) and Northern North China (NNC) largely changed in the same direction as the Arctic Oscillation (AO) for most of the 1650–1975 study period. An increasing/decreasing AO index correlated with a higher propensity for drought/flood in both regions.
• The frequency of extreme and severe drought events in the UH significantly increased with a rising AO index, while severe flood events showed a decreasing trend. NNC exhibited a tendency for severe drought events only on the 30-year scale and was more prone to severe flood events during periods of relatively low AO values.
• The teleconnection between AO and DF in UH and NNC exhibited phase shifts (positive/negative correlations) over time, influencing the correlation between DF in the two areas.
• Both AO and DF in UH and NNC share common cyclical variations: inter-annual cycles (approximately 3–6 years), inter-decadal cycles (approximately 12 years), and multi-decadal cycles (approximately 20–30 years).
• Granger Causality Tests revealed that the AO is a significant predictor of DF in both the UH and NNC, primarily on the multi-decadal scale.
• Abrupt increases/decreases in the AO index made the UH more prone to drought/flood, respectively, on both inter-decadal and multi-decadal scales. NNC showed a weaker response but was more likely to experience drought with abrupt AO increases on the inter-annual scale.

Contributions

• Deepens the scientific understanding of common atmospheric factors (specifically AO) driving concurrent drought and flood occurrences in the Upper Hanjiang River and Northern North China, which are critical areas for the South-to-North Water Diversion project.
• Enriches historical climate research by utilizing long-term (1650–1975) reconstructed climate series, addressing the limitations of studies often restricted to the instrumental period.
• Provides a scientific basis for improving drought and flood prediction accuracy and informing water resource management strategies in the study regions, particularly for disaster prevention and mitigation.
• Investigates the influence of AO on multi-decadal scale drought and flood variability in China, a less-explored area due to data scarcity.

Funding

• National Key Research and Development Program of China (No.2018YFA0605603)
• National Social Science Foundation of China Major Projects (No.22&ZD223)

Citation

@article{Zhang2025Concurrent,
  author = {Zhang, Xiaodan and Ren, Guoyu and Yang, Yuda},
  title = {Concurrent occurrence of droughts and floods between the upper Hanjiang river and Northern North China at multi-temporal scales: an association with Arctic Oscillation},
  journal = {Climate Dynamics},
  year = {2025},
  doi = {10.1007/s00382-025-08006-x},
  url = {https://doi.org/10.1007/s00382-025-08006-x}
}