Recently, Eos, the science news magazine of the American Geophysical Union (AGU), featured the paper "Interannual Variations in the Day-to-Day Temperature Variability in the Northern Hemisphere and Possible Causalities" by Academician Congbin Fu's team from the School of Atmospheric Sciences as an Editor's Highlight (Eos.org: https://eos.org/editor-highlights/drivers-of-day-to-day-temperature-swings-across-continents). It is reported that less than 2% of AGU journal papers are selected for coverage in this column.
Day-to-day temperature variability has a profound impact on human health, ecosystem stability, and socioeconomic activities, drawing significant attention. However, previous research has mainly focused on how global warming affects its long-term trends and extreme intensity. In this study, instead, focuses on how it fluctuates from year to year (i.e., interannual variability) and the underlying physical mechanisms. Using observational data, reanalysis datasets, and CMIP6 multi-model simulations from 1961 to 2014, the study identified large-scale dominant modes in Eurasia and North America. These modes exhibit significant seasonal differences: the winter dominant mode explains approximately 40%–45% of the total variance, while the summer mode explains 18%–22%, indicating that the interannual variation of day-to-day temperature variability has clear spatial structures and seasonal dependencies. Further diagnostic analysis reveals that this variability is primarily controlled by the north-south movement of cold and warm air masses. The drivers governing this process shift markedly with the seasons. In winter, day-to-day temperature variability is mainly regulated by large-scale atmospheric circulation patterns, including the Arctic Oscillation, El Niño–Southern Oscillation, and the Pacific–North American teleconnection. These circulation anomalies enhance cold air southward intrusions and warm air northward transport by altering the temperature gradient and storm track activity over mid-to-high latitudes, thereby amplifying day-to-day temperature fluctuations. In summer, the influence of large-scale circulation weakens significantly, and local land-atmosphere feedback processes become more prominent, with the snow-albedo-temperature positive feedback mechanism playing a dominant role. These physical processes collectively reshape the regional temperature gradient and effectively modulate the frequency, intensity, and atmospheric circulation systems of storm activity. Evaluations based on the Coupled Model Intercomparison Project Phase 6 (CMIP6) multi-model ensemble show that current climate models can reasonably reproduce the observed major spatial modes and their relationships with circulation anomalies, with higher confidence in winter simulations and larger uncertainties in summer.
Overall, this study provides new insights into understanding the interannual variation mechanisms of day-to-day temperature variability, complementing previous studies focusing on long-term trends and extreme intensity, and offers a scientific basis for improving climate risk predictions and adaptation strategies.
The paper was published on March 2, 2025, in the Nature-index journal JGR-Atmospheres. Academician Congbin Fu is the corresponding author, and Assistant Professor Qi Liu is the first author. This research was supported by the National Key Research and Development Program of China (2023YFF0805503), the Jiangsu Collaborative Innovation Center for Climate Change, and the Frontiers Science Center for Critical Earth Material Cycles at Nanjing University.
Paper Information:
Liu, Q., Fu, C. (2026). Interannual variations in the day-to-day temperature variability in the northern hemisphere and possible causalities. Journal of Geophysical Research: Atmospheres, 131, e2025JD045754. https://doi.org/10.1029/2025JD045754
Eos News Coverage:
https://eos.org/editor-highlights/drivers-of-day-to-day-temperature-swings-across-continents