Men et al. (2026) The global response patterns of diurnal temperature range to soil moisture under different climatic backgrounds

Identification

• Journal: Climate Dynamics
• Year: 2026
• Date: 2026-04-01
• Authors: Jingyu Men, Xi Chen, Kang Jiang, Pengshuai Bi, Na Huang, Riping Gao, Changlin Wu, Fangxiao Zhang, Zhanrui Huang, Enze Gao, Yijia Yao, Zhihua Pan
• DOI: 10.1007/s00382-026-08131-1

Research Groups

• College of Resources and Environmental Sciences, China Agricultural University, Beijing, China
• CMA-CAU Joint Laboratory of Agriculture Addressing Climate Change, Beijing, China
• School of Geography and Tourism, Qufu Normal University, Rizhao, China

Short Summary

This study investigates the global response patterns of diurnal temperature range (DTR) to soil moisture (SM) variations across different climatic backgrounds from 1980 to 2022, revealing a significant, often nonlinear, negative correlation where DTR is more sensitive to SM changes under low SM conditions.

Objective

• To examine global response patterns of diurnal temperature range (DTR) to soil moisture (SM) across different climatic backgrounds.
• To analyze the temporal and spatial patterns of SM and DTR and investigate the characteristic responses of DTR to SM variations.
• To provide scientific insights for revealing the influence mechanism of SM on DTR.

Study Configuration

• Spatial Scale: Global land areas (excluding Antarctica).
• Temporal Scale: 1980 to 2022 (43 years).

Methodology and Data

• Models used: Theil-Sen trend analysis, Mann-Kendall test, Pearson correlation analysis, piecewise linear function with dynamic optimization (for nonlinear SM-DTR relationship), surface energy balance principle.
• Data sources:
  • ERA5-Land reanalysis (hourly and monthly: 0-7 cm soil moisture, evaporation, surface latent heat flux, surface sensible heat flux, surface net solar radiation, surface shortwave radiation, surface thermal radiation, 2-meter air temperature for Tmax, Tmin, DTR).
  • ERA5 reanalysis (monthly: specific humidity, total cloud cover).
  • International Soil Moisture Network (ISMN) (in-situ observations for SM validation, 0-10 cm layer).
  • Global Land Cover-SHARE dataset (land cover, 30 arc seconds spatial resolution).
  • GIMMS-3G+ (Version 1.2) NDVI (twice-monthly, 0.0833° spatial resolution).
  • GEBCO_2022 Grid (Digital Elevation Model, 15 arc seconds spatial resolution).

Main Results

• From 1980 to 2022, global land average DTR increased by 0.026 °C per decade (p < 0.01) over 56.65% of global land areas, while global average SM decreased by 0.0025 m³/m³ per decade (p < 0.01) in 77.58% of areas.
• Global mean DTR and SM exhibited a significant negative correlation (R = -0.77, p < 0.01), with 77.58% of regions showing a negative correlation (99.43% significant at p < 0.05).
• The negative correlation between DTR and SM is notably nonlinear; DTR shows greater sensitivity to SM changes under low SM conditions (e.g., SM < 0.120 m³/m³ in southern North America, SM < 0.112 m³/m³ in Western Asia).
• Four distinct response patterns were identified based on SM and DTR trends:
  • SD1 (SM↑, DTR↑): Approximately 3.9% of global land, mainly high-latitude. Increased SM leads to reduced surface albedo (due to snow/permafrost melt) boosting shortwave radiation and Tmax, while nighttime temperatures below 0 °C weaken Tmin insulation, resulting in increased DTR.
  • SD2 (SM↑, DTR↓): Approximately 18.5% of global land (e.g., Indian subcontinent, southern Africa). Enhanced latent heat flux suppresses daytime warming, and higher specific humidity slows nighttime cooling, leading to reduced DTR.
  • SD3 (SM↓, DTR↑): Approximately 53.8% of global land (widespread, excluding deserts/high-latitudes). Decreasing SM limits evaporation, reduces latent heat flux, and increases sensible heat flux, causing DTR to increase, especially in dry, hot areas.
  • SD4 (SM↓, DTR↓): Approximately 23.8% of global land (e.g., northern Africa deserts, northern North America). Despite decreasing SM, these regions maintain relatively high SM levels and are energy-limited. Increased radiative input enhances latent heat flux, suppressing daytime warming and slowing nighttime cooling, leading to decreased DTR.
• The recent increase in DTR (since approximately 1991) is primarily due to Tmax increasing persistently faster than Tmin.

Contributions

• Provides a comprehensive global-scale analysis of the spatiotemporal response patterns of DTR to SM, addressing the previously underexplored global articulation of this relationship.
• Identifies and quantifies the significant nonlinear relationship between DTR and SM, demonstrating DTR's greater sensitivity under low SM conditions and linking it to water-limited vs. energy-limited surface energy balance regimes.
• Categorizes global land areas into four distinct SM-DTR trend patterns, offering detailed mechanistic explanations for each, including the counterintuitive DTR increases in some high-latitude SM-increasing regions and DTR decreases in some SM-declining regions.
• Highlights the underestimated impact of SM changes on DTR trends, providing a new perspective on the driving mechanisms of DTR changes beyond cloud cover.
• Emphasizes the increasing importance of SM in modulating global DTR under future climate change scenarios, particularly given projected increases in soil moisture drought conditions.

Funding

• National Key Research and Development Program of China (No. 2023YFF0805703)
• National Natural Science Foundation of China (No. 42271268)

Citation

@article{Men2026global,
  author = {Men, Jingyu and Chen, Xi and Jiang, Kang and Bi, Pengshuai and Huang, Na and Gao, Riping and Wu, Changlin and Zhang, Fangxiao and Huang, Zhanrui and Gao, Enze and Yao, Yijia and Pan, Zhihua},
  title = {The global response patterns of diurnal temperature range to soil moisture under different climatic backgrounds},
  journal = {Climate Dynamics},
  year = {2026},
  doi = {10.1007/s00382-026-08131-1},
  url = {https://doi.org/10.1007/s00382-026-08131-1}
}