Fig. 3: Diurnal cycles of change.

Diurnal changes (for perturbations of black carbon BC, carbon dioxide CO2 and sulfate SO4) in (a–c) temperature up to 760 hPa, (d–f) Richardson number Ri up to 760 hPa and (g–i) near-surface BC concentrations and planetary boundary layer height (PBLH), in the China (CHI) region for the winter season. In (g–i) star symbols indicate hours for which changes are statistically significant by Student’s t test.