Nikta et al. (2026) Lagged global relationships between teleconnection indices and hydrological drought: a continental-scale analysis using ERA5-Land runoff data

Identification

• Journal: Journal of Hydrology
• Year: 2026
• Date: 2026-08-18
• Authors: Mohammad Mahdi Nikta, Ahmad Sharafati, Alireza Hadian, Siyamak Doroudi, Reza Farzad, Yusef Kheyruri, Zaher Mundher Yaseen‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬
• DOI: 10.1016/j.jhydrol.2026.136257

Research Groups

• Department of Civil Engineering, SR.C., Islamic Azad University, Tehran, Iran
• New Era and Development in Civil Engineering Research Group, Scientific Research Center, Al-Ayen Iraqi University (AUIQ), Nasiriyah, Iraq
• Department of Civil Engineering, Sharif University of Technology, Tehran, Iran
• Civil and Environmental Engineering Department, King Fahd University of Petroleum & Minerals, Dhahran, Saudi Arabia

Short Summary

This study evaluates the lagged correlation between five teleconnection indices and hydrological drought globally to identify optimal lag times for early drought detection. It finds that optimal lags are generally shorter at continental scales than at the global scale.

Objective

• To investigate the relationship and determine the optimal lag time (ranging from 0 to 12 months) between five teleconnection indices and the Standardized Runoff Index (SRI) on both global and continental scales.

Study Configuration

• Spatial Scale: Global and continental scale, utilizing a spatial resolution of 9 km.
• Temporal Scale: 1980 to 2024.

Methodology and Data

• Models used: Pearson correlation coefficient, Standardized Runoff Index (SRI), and probability density analysis.
• Data sources: ERA5-Land runoff dataset and five teleconnection indices.

Main Results

• Optimal lag times for the response of hydrological drought to teleconnection indices are shorter when analyzed at a continental scale compared to a global scale.
• Strong and meaningful correlations between SRI and specific teleconnection indices were identified across various global regions at these optimal lags.
• The study successfully identified the leading teleconnection index for each continent by determining the index with the strongest correlation at its respective optimal lag.

Contributions

• Provides a comprehensive continental-scale mapping of the lagged influence of teleconnection indices on hydrological drought, offering a basis for proactive water resource management and early warning systems.

Funding

• Not specified in the provided text.

Citation

@article{Nikta2026Lagged,
  author = {Nikta, Mohammad Mahdi and Sharafati, Ahmad and Hadian, Alireza and Doroudi, Siyamak and Farzad, Reza and Kheyruri, Yusef and Yaseen‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬‬, Zaher Mundher},
  title = {Lagged global relationships between teleconnection indices and hydrological drought: a continental-scale analysis using ERA5-Land runoff data},
  journal = {Journal of Hydrology},
  year = {2026},
  doi = {10.1016/j.jhydrol.2026.136257},
  url = {https://doi.org/10.1016/j.jhydrol.2026.136257}
}