Pradhan et al. (2026) Imprints of terrestrial water fluxes on tropospheric stable water isotopes revealed by satellite observations and complex network analysis

Identification

Journal: Journal of Hydrology
Year: 2026
Date: 2026-02-05
Authors: Rohit Pradhan, Raghavendra Pratap Singh, Nimisha Singh, Shard Chander, Praveen K. Gupta, Mihir Kumar Dash
DOI: 10.1016/j.jhydrol.2026.135087

Research Groups

Centre for Ocean, River, Atmosphere and Land Sciences, Indian Institute of Technology Kharagpur, Kharagpur, India
Earth and Planetary Sciences and Applications Area, Space Applications Centre (ISRO), Ahmedabad, India
Indian Institute of Remote Sensing, ISRO, Dehradun, India

Short Summary

This study investigates the relationship between the isotopic composition of atmospheric water vapor (δD) and the surface water balance (evapotranspiration minus precipitation, ET-P) using satellite observations and model data. It reveals strong positive correlations and complex network teleconnections, demonstrating the utility of water vapor isotopes for climate network analysis and model evaluation.

Objective

To investigate the relationship between the isotopic composition of atmospheric water vapor (δD) and the surface water balance (ET-P) using satellite-observed and model-based datasets.
To demonstrate the utility of water vapor isotopes in constructing climate networks and offer a novel diagnostic tool for evaluating the performance of isotope-enabled climate and hydrological models.

Study Configuration

Spatial Scale: Global, with a focus on tropical forested regions (Amazon, Congo Basin, Southeast Asia), equatorial Pacific, eastern Indian Ocean, and Northeast India.
Temporal Scale: 31-year period.

Methodology and Data

Models used: isoGSM (isotope-enabled Global Spectral Model) in both nudged and free-running configurations.
Data sources: Satellite observations (AIRS - Atmospheric Infrared Sounder) for atmospheric water vapor isotopic composition (δD), and model-based data (isoGSM) for δD and surface water balance (ET-P). Complex network analysis using time-lagged correlations.

Main Results

Strong positive correlations (r > 0.7) were found between δD and ET–P over tropical forested regions, including the Amazon, Congo Basin, and Southeast Asia.
Nudged isoGSM showed superior overall performance compared to free-running isoGSM, while AIRS satellite data was more effective in the tropics.
A complex network constructed from time-lagged correlations between ET–P and δD over 31 years identified nearly 1.4 million significant links (p < 0.001).
The network revealed both short- and long-range teleconnections, characterized by a bimodal distribution of link lengths and dominant zero-lag interactions.
High node connectivity was concentrated over the equatorial Pacific, eastern Indian Ocean, and tropical forests, indicating the intertwined roles of vegetation and large-scale ocean–atmosphere dynamics.
Regional case studies in the Amazon, Congo, and Northeast India highlighted distinct teleconnection patterns influenced by sea surface temperature (SST) anomalies, Walker circulation, and moisture recycling.

Contributions

Provides novel insights into the imprints of terrestrial water fluxes on tropospheric stable water isotopes using satellite observations and complex network analysis.
Demonstrates the utility of water vapor isotopes for constructing climate networks, offering a new approach to understand hydrological teleconnections.
Introduces a novel diagnostic tool for evaluating the performance of isotope-enabled climate and hydrological models.

Funding

Not available in the provided text.

Citation

@article{Pradhan2026Imprints,
  author = {Pradhan, Rohit and Singh, Raghavendra Pratap and Singh, Nimisha and Chander, Shard and Gupta, Praveen K. and Dash, Mihir Kumar},
  title = {Imprints of terrestrial water fluxes on tropospheric stable water isotopes revealed by satellite observations and complex network analysis},
  journal = {Journal of Hydrology},
  year = {2026},
  doi = {10.1016/j.jhydrol.2026.135087},
  url = {https://doi.org/10.1016/j.jhydrol.2026.135087}
}

Original Source: https://doi.org/10.1016/j.jhydrol.2026.135087