Mineral Dust Instantaneous Radiative Forcing in the Arctic

Mineral dust sources at high and low latitudes contribute to atmospheric dust loads and dust deposition in the Arctic. With dust load estimates from Groot Zwaaftink et al. (2016, https://doi. org/10.1002/2016JD025482), we quantify the mineral dust instantaneous radiative forcing (IRF) in the Arctic for the year 2012. The annual-mean top of the atmosphere IRF is 0.225 W/m(2), with the largest contributions from dust transported from Asia south of 60 degrees N and Africa. High-latitude (>60 degrees N) dust sources contribute about 39% to top of the atmosphere IRF and have a larger impact (1 to 2 orders of magnitude) on IRF per emitted kilogram of dust than low-latitude sources. Mineral dust deposited on snow accounts for nearly all of the bottom of the atmosphere IRF of 0.135 W/m(2). More than half of the bottom of the atmosphere IRF is caused by dust from high-latitude sources, indicating substantial regional climate impacts rarely accounted for in current climate models. Plain Language Summary Mineral dust sources at high and low latitudes contribute to atmospheric dust loads and dust deposition in the Arctic. We quantify the annual-mean radiative forcing (RF) in the Arctic to be 0.225 W/m(2) at the top of the atmosphere. The largest contributions are from dust transported from Asia south of 60 degrees N and Africa. High-latitude (>60 degrees N) dust sources contribute about 39% to top of the atmosphere RF and have a larger (1 to 2 orders of magnitude) impact on RF per emitted kilogram of dust. Mineral dust deposited on snow accounts for nearly all of the bottom of the atmosphere RF of 0.135 W/m(2). More than half of the bottom of the atmosphere RF is caused by dust from high-latitude sources, indicating substantial regional climate impacts rarely accounted for in current climate models.