Influence of Dust on Climate during the late Palaeozoic ice age

Dust in the atmosphere affects climate by directly absorbing and scattering solar radiation. In present days, most of dust is emitted from dry regions over North Africa and Arabian Peninsula. It has been shown that it impact on global mean surface temperature, African monsoon, the number of tropical cyclones over the Atlantic Ocean, ENSO variability and the strength of Atlantic meridional ocean circulation (AMOC). The climate of late Paleozoic ice age bears some similarity to late Cenozoic climate. However, late Paleozoic ice age was a period of continental convergence and supercontinents formation. On different continental configurations, the area of dry regions may vary considerably, so that dust emissions and atmospheric dust loading changed accordingly. As  expected, the impact of dust on climate during this period was also very different from that of present days. In this work, we use the fully coupled global climate model CESM1.2.2 to examine the influence of dust on climate during late Palaeozoic ice age. Dust aerosols simulated by bulk aerosol model alter atmospheric radiation through scattering and absorbing both shortwave and longwave radiation. Results show that during late Palaeozoic ice age, sources of dust were mainly distributed on the western continent in the subtropics. The total amount of the atmospheric dust loading was less than that of present days due to the smaller subtropical continental area. Such dust induced a significant cooling of surface temperature at low latitudes by altering radiation. Dust falling on southern hemisphere continents covered by ice and snow caused a rising of surface temperature.