1625 / 2019-08-23 11:50:46

Variability in individual particle structure and mixing states between the glacier–snowpack and atmosphere in the northeastern Tibetan Plateau

15、冰冻圈科学 > 专题5：冰冻圈大气污染的来源、迁移转化过程和影响

Aerosols affect the earth's temperature and climate by altering the radiative properties of the atmosphere. Changes in the composition, morphology structure and mixing states of aerosol components will cause significant changes in radiative forcing in the atmosphere. This work focused on the physicochemical properties of light-absorbing particles (LAPs) and their variability through deposition process from the atmosphere to the glacier/snowpack interface based on large-range observation in northeast Tibetan Plateau, and laboratory transmission electron microscope (TEM) and energy dispersive X-ray spectrometer (EDX) measurements. The results showed that LAPs particle structures changed markedly in the snowpack compared to those in the atmosphere due to black carbon (BC)/organic matter (OM) particle aging and salt-coating condition changes. Considerably more aged BC and OM particles were observed in the glacier and snowpack surfaces than in the atmosphere, as the concentration of aged BC and OM varied in all locations by 4%-16% and 12%-25% in the atmosphere, respectively, whereas they varied by 25%-36% and 36%-48%, respectively, in the glacier/snowpack surface. Similarly, the salt-coated particle ratio of LAPs in the snowpack is lower than in the atmosphere. Albedo change contribution in the Miaoergou, Yuzhufeng and Qiyi Glaciers is evaluated using the SNICAR model for glacier surface distributed impurities. Due to the salt-coating state change, the snow albedo decreased by 16.7%-33.9% compared to that in the atmosphere. Such great change may cause more strongly enhanced radiative heating than previously thought, suggesting that the warming effect from particle structure and mixing change of glacier/snowpack LAPs may have markedly affected the climate on a global scale in terms of direct forcing in the Cryosphere.