Yang et al. (2026) Quantitative assessment impact of anthropogenic heat flux on global urban evapotranspiration retrieval at multiple temporal scales

Identification

• Journal: Journal of Hydrology
• Year: 2026
• Date: 2026-03-04
• Authors: Zi Yang, Xin Pan, Hongjun Zhu, Fanggang Li, Xiangjin Meng, Rufat Guluzade, Yuanbo Liu, Suyi Liu, Wen He, Zhenwei Wang, Yingbao Yang
• DOI: 10.1016/j.jhydrol.2026.135246

Research Groups

• College of Geography and Remote Sensing, Hohai University, Nanjing, China
• Jiangsu Key Laboratory of Soil and Water Processes in Watershed, Hohai University, Nanjing, China
• School of Earth Sciences and Engineering, Hohai University, Nanjing, China
• State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China
• Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing, China

Short Summary

This study quantified the global impact of anthropogenic heat flux (AHF) on urban evapotranspiration (ET) estimation by comparing remote sensing-derived ET with and without AHF across 668 cities worldwide. It found that neglecting AHF leads to significant ET underestimation, particularly in cold regions and megacities, with discrepancies peaking in summer.

Objective

• To quantify the global impact of anthropogenic heat flux (AHF) on urban evapotranspiration (ET) retrieval accuracy at multiple temporal scales.
• To identify the conditions under which AHF should be considered in urban ET estimation.
• To demonstrate how incorporating AHF improves ET retrieval accuracy and strengthens the assessment of urban water and energy budgets.

Study Configuration

• Spatial Scale: Global, covering 668 cities worldwide, with specific analyses for cold regions, Europe, megacities, arid zones, and compact high-rise/mid-rise building districts.
• Temporal Scale: Annual and seasonal (summer, winter).

Methodology and Data

• Models used: Remote sensing-derived ET models, modified to include and exclude anthropogenic heat flux (AHF) in the surface energy balance equation.
• Data sources: Remote sensing data.

Main Results

• On an annual scale, neglecting AHF resulted in significant ET underestimation:
  • Absolute (relative) differences: 2.23 W/m² (7.9%) in cold regions.
  • Absolute (relative) differences: 2.56 W/m² (9.8%) in Europe.
  • Absolute (relative) differences: 2.81 W/m² (11.0%) in megacities.
  • In cold-region megacities, relative differences reached 16.0%, approximately 1.8 times higher than in medium-sized cities in arid zones.
  • In compact high-rise and mid-rise building districts, differences increased to 9.70 W/m² (32.7%).
• Seasonally, the discrepancy peaked in summer (3.95 W/m²), nearly four times that in winter.
  • During summer, cold-region megacities exhibited the largest differences (mean 8.49 W/m²).
  • Maximum values in summer reached up to 20.80 W/m² in compact high-rise and mid-rise building districts.

Contributions

• Provides the first global-scale quantitative evidence identifying the specific conditions under which anthropogenic heat flux (AHF) should be considered in urban evapotranspiration (ET) estimation.
• Demonstrates that the incorporation of AHF significantly improves the accuracy of ET retrieval in urban environments.
• Enhances the robustness of urban water and energy budget assessments by accounting for AHF.

Funding

Not specified in the provided text.

Citation

@article{Yang2026Quantitative,
  author = {Yang, Zi and Pan, Xin and Zhu, Hongjun and Li, Fanggang and Meng, Xiangjin and Guluzade, Rufat and Liu, Yuanbo and Liu, Suyi and He, Wen and Wang, Zhenwei and Yang, Yingbao},
  title = {Quantitative assessment impact of anthropogenic heat flux on global urban evapotranspiration retrieval at multiple temporal scales},
  journal = {Journal of Hydrology},
  year = {2026},
  doi = {10.1016/j.jhydrol.2026.135246},
  url = {https://doi.org/10.1016/j.jhydrol.2026.135246}
}