Surface solar radiation and day-to-day temperature variability in China during 1961–2022: evidence from the dimming–brightening transition

Abstract

Climate change affects natural and human systems not only through changes in mean temperature but also through rapid temperature fluctuations between consecutive days. Using homogenized daily mean and maximum temperature observations and reconstructed surface solar radiation at 1759 matched stations in China during 1961–2022, we evaluated the seasonal cycles, probability distributions, and long-term trends of day-to-day temperature variability (DTD and DTDMAX). The regression adjustment was applied to extract the fitted component of temperature anomalies that is statistically correlated with simultaneous radiation anomalies. The results show that, both of DTD and DTDMAX exhibited higher values in winter and spring than in summer and autumn, and the radiation-associated differences were stronger for DTDMAX. The distributions shifted leftward after regression adjusted for most river basins, with substantially larger distributional contrasts for DTDMAX than for DTD. The annual DTD and DTDMAX in most regions showed an interdecadal transition, which is highly consistent with ‘global dimming and brightening’. The increasing trends in DTD and DTDMAX during 1991–2022 were weaker in the regression adjusted series than in the original series, indicating that part of their long-term increase was statistically associated with contemporaneous solar radiation. The slope changed from 0.015 to −0.004 °C/10a for DTD, and from 0.049 to 0.001 °C/10a for DTDMAX in the Yangtze River Basin. After removing linear trends and controlling for annual precipitation, positive correlations with day-to-day radiation variability occurred in 81.28% of grid cells for DTD and 89.60% for DTDMAX. The results show that short-term thermal variability is associated with surface radiation variability, particularly for daily maximum temperature. These findings advance our understanding of short-term temperature variability across China, with meaningful implications for the climate related impacts and environmental risk under a warming climate.