Dust Radiative Effects on Climate by Glaciating Mixed‐Phase Clouds

• Published in: Geophysical research letters Vol. 46; no. 11; pp. 6128 - 6137
• Main Authors: Shi, Yang, Liu, Xiaohong
• Format: Journal Article
• Language: English
• Published: Washington John Wiley & Sons, Inc 16.06.2019; American Geophysical Union (AGU)
• Subjects: Atmospheric models; Atmospheric particulates; Climate; Climate effects; Climate models; Cloud formation; Cloud water; Clouds; Computer simulation; Cooling; Cooling effects; Crystals; Dust; dust indirect effects; Dust storms; Earth; Energy budget; Energy policy; Federal agencies; Freezing; Global climate; Global climate models; Ice; Ice crystal formation; Ice crystals; Ice formation; Ice nucleation; mixed‐phase clouds; Northern Hemisphere; Nucleation; Phase transitions; Radiative forcing; Northern Hemisphere; Arctic region
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2019GL082504

Mineral dust plays an important role in the primary formation of ice crystals in mixed‐phase clouds by acting as ice nucleating particles (INPs). It can influence the cloud phase transition and radiative forcing of mixed‐phase clouds, both of which are crucial to global energy budget and climate. In this study, we investigate the dust indirect effects on mixed‐phase clouds through heterogeneous ice nucleation with the U.S. Department of Energy (DOE) Energy Exascale Earth System Model (E3SM). Dust and INP concentrations simulated from two versions of E3SM with three ice nucleation parameterizations were evaluated against observations in the Northern Hemisphere. Constrained by these observations, E3SM shows that dust INPs induce a global mean net cloud radiative effect of 0.05 to 0.26 W/m2 with the predominant warming appearing in the Northern Hemisphere midlatitudes. However, a cooling effect is found in the Arctic due to reduced longwave cloud forcing. Plain Language Summary Mineral dust is one of the most important ice nucleating particles in the atmosphere. In other words, it can initiate ice crystal formation in cold clouds. This process has large impacts on cloud liquid and ice content and cloud radiative forcing, which are crucial to global energy budget and climate. In this study, we investigate the dust indirect effects on mixed‐phase clouds through the freezing of cloud water using global climate models. Dust and ice nucleating particle concentrations from model simulations were evaluated against observations focusing on the Northern Hemisphere. Constrained by these observations, the model results indicate that dust induces a global mean net warming cloud effect. The warming is found predominantly in the Northern Hemisphere midlatitudes, whereas a cooling effect is found in the Arctic. Key Points Dust indirect effects on mixed‐phase clouds by acting as ice nucleating particles are investigated with global climate models Dust induces a global mean net warming cloud radiative effect The dust warming effect is located predominantly in the Northern Hemisphere midlatitudes, while a cooling effect is found in the Arctic