Sang et al. (2026) Analysis of intraday urban thermal anisotropy and downward shortwave radiation through UAV experiment and coupled model

Identification

• Journal: International Journal of Applied Earth Observation and Geoinformation
• Year: 2026
• Date: 2026-09-22
• Authors: Xinguang Sang, Xiaobo Luo, Yidong Peng, Panpan Zhu
• DOI: 10.1016/j.jag.2026.105582

Research Groups

• School of Intelligent Engineering, Chongqing Electric Power College, China
• College of Artificial Intelligence, Chongqing University of Posts and Telecommunications, China
• Key Laboratory of Tourism Multisource Data Perception and Decision, Ministry of Culture and Tourism, China

Short Summary

This study presents a novel framework for analyzing urban thermal anisotropy (UTA) by integrating UAV data with coupled modeling. The framework exhibits robustness in simulating UTA at a scale of 0.4 × 0.4 km2.

Objective

• Investigate the diurnal relationship between downward shortwave radiation (DSWR) and urban thermal anisotropy (UTA)
• Evaluate the angular effects of instantaneous observations on UTA

Study Configuration

• Spatial Scale: 0.4 × 0.4 km2 area in Chongqing, China
• Temporal Scale: Hourly resolution from 08:30 to 18:35 local time

Methodology and Data

• Models used: GRay model, AU3SM model, and IRT measurements
• Data sources: UAV-based TIR data, satellite sampling references, and ground temperature measurements

Main Results

• UTA variation follows a regular pattern with maximum near the solar direction above the slope
• DBT intensity peaks around 14:00, after which both the hotspot magnitude and overall values decline
• DSWR increases rapidly to a peak around 12:10, remains relatively stable during midday, and then declines sharply after 14:00

Contributions

• The framework provides essential reference data for angular normalization of thermal radiation
• It enhances the Urban Digital Twin by providing terrain-corrected radiation data via the GRay-AU3SM-IRT

Funding

• National Natural Science Foundation of China under Grant 42571451 and 62576061
• Science and Technology Research Program of Chongqing Municipal Education Commission under Grant KJQN202500635 and KJQN202500646
• General Program of Chongqing Municipal Natural Science Foundation under Grant CSTB2025NSCQ-GPX1259

Citation

@article{Sang2026Analysis,
  author = {Sang, Xinguang and Luo, Xiaobo and Peng, Yidong and Zhu, Panpan},
  title = {Analysis of intraday urban thermal anisotropy and downward shortwave radiation through UAV experiment and coupled model},
  journal = {International Journal of Applied Earth Observation and Geoinformation},
  year = {2026},
  doi = {10.1016/j.jag.2026.105582},
  url = {https://doi.org/10.1016/j.jag.2026.105582}
}