Sun et al. (2025) Enhanced spring precipitation in central Asia induced by ENSO under global warming

Identification

• Journal: Climate Dynamics
• Year: 2025
• Date: 2025-12-19
• Authors: Lin Sun, Yanting Zhang, Xiao‐Tong Zheng
• DOI: 10.1007/s00382-025-07990-4

Research Groups

• State Key Laboratory of Physical Oceanography, Ocean University of China, Qingdao, China
• College of Oceanic and Atmospheric Sciences, Ocean University of China, Qingdao, China
• Laboratory for Ocean Dynamics and Climate, Qingdao Marine Science and Technology Center, Qingdao, China

Short Summary

This study investigates how El Niño–Southern Oscillation (ENSO) modulates spring precipitation in Central Asia (CA) under global warming, finding a significant increase in spring precipitation, particularly over southwestern CA, primarily driven by intensified horizontal moisture advection due to enhanced ENSO-related meridional circulation anomalies and an amplified North Atlantic teleconnection.

Objective

• To investigate how ENSO-induced spring hydroclimatic anomalies over Central Asia (CA) will respond to global warming.
• To determine whether thermodynamic or dynamic processes play the dominant role in the changes of ENSO-induced spring precipitation anomalies over CA under global warming, and to identify the associated physical mechanisms.

Study Configuration

• Spatial Scale: Central Asia (CA) (35°–55°N, 50°–90°E), with a focus on the southern/southwestern region (35°–45°N, 60°–80°E). North Atlantic (25°–47.5°N, 80°–5°W) as a teleconnection source region.
• Temporal Scale:
  • Observational/Reanalysis: 1960–2021
  • Historical simulations: 1950–1999
  • Future simulations: 2045–2094 (under SSP5–8.5 high-emission scenario)
  • Season: Spring (February–May, FMAM)

Methodology and Data

• Models used:
  • Community Earth System Model Large Ensemble (CESM-LE; 35 ensemble members)
  • Coupled Model Intercomparison Project Phase 6 (CMIP6; 28 models)
  • Atmospheric Model Intercomparison Project (AMIP; 11 atmospheric general circulation models)
  • AMIP-future4K (AMIP with an additional non-uniform 4 K warming on SST)
• Data sources:
  • Japanese 55-year Reanalysis (JRA-55) for monthly precipitation.
  • Extended Reconstructed Sea Surface Temperature version 5 (ERSSTv5) for SST.
  • NOAA Climate Prediction Center for Niño 3.4 index.

Main Results

• Spring precipitation in Central Asia (CA) is projected to significantly increase during ENSO decay springs under high-emission scenarios (SSP5-8.5), particularly over southwestern CA.
• The increase in precipitation is greater than that of evapotranspiration, leading to a net moisture gain in spring and an enhanced wetting trend.
• Moisture budget analysis reveals that the enhanced spring precipitation is primarily driven by intensified horizontal moisture advection (specifically, changes in ENSO-related circulation anomalies acting on background humidity), with the meridional component playing the most dominant role.
• ENSO induces a positive precipitation anomaly over the North Atlantic (NA) in spring, which is projected to intensify under global warming.
• This enhanced NA precipitation acts as a wave source, exciting Rossby wave trains that propagate eastward along the subtropical westerly jet, triggering atmospheric circulation responses across the Eurasian midlatitudes.
• These circulation responses are characterized by an anticyclonic anomaly over CA and a cyclonic anomaly over North Africa, which collectively strengthen southwesterly moisture transport into CA.
• The coupling between ENSO and the North Atlantic Precipitation Index (NAPI) is significantly enhanced under global warming, with the ensemble mean correlation increasing from approximately 0.7 to 0.9.

Contributions

• Advances understanding of future Central Asian hydroclimatic changes by systematically investigating the modulation of spring precipitation by ENSO under global warming.
• Emphasizes the critical role of enhanced ENSO-induced horizontal moisture transport, particularly the meridional component, in shaping future CA precipitation.
• Clarifies the underlying physical mechanisms, highlighting the amplification of a tropical–midlatitude teleconnection pathway originating from an intensified North Atlantic wave source under warming.
• Provides insights relevant for future climate adaptation and water resource management in Central Asia.

Funding

• National Natural Science Foundation of China (42305037, 42475026)
• Natural Science Foundation of Shandong (ZR2022QD139)

Citation

@article{Sun2025Enhanced,
  author = {Sun, Lin and Zhang, Yanting and Zheng, Xiao‐Tong},
  title = {Enhanced spring precipitation in central Asia induced by ENSO under global warming},
  journal = {Climate Dynamics},
  year = {2025},
  doi = {10.1007/s00382-025-07990-4},
  url = {https://doi.org/10.1007/s00382-025-07990-4}
}