Assessment of the combined radiative effects of black carbon in the atmosphere and snowpack in the Northern Hemisphere constrained by surface observations

Abstract

In this study, the total radiative effect of black carbon (BC) in both the atmosphere and seasonal snowpack across the snow-covered area has been investigated over the Northern Hemisphere. Our results show that the annual total BC radiative effect over the snow-covered area at the top of the atmosphere varies widely from 0.93 W m⁻² in Greenland to 5.97 W m⁻² on the Tibetan Plateau, corresponding to contributions of snowpack BC of 10% and 70%, respectively. This highlights the important contribution of BC in snow to the assessment of the total BC radiative effect. In addition, we observed that the annual total BC radiative effect at the snow surface was generally positive, implying a dominant role of surface warming due to snowpack BC, especially in the Tibetan Plateau, where the annual total BC surface radiative effect can reach up to 4.17 W m⁻², indicating that BC exerts a significant influence on the snowmelt and glacier mass balance in this high-elevation region.