Abstract

Abstract. A discrepancy of up to 5 orders of magnitude between ice crystal and ice nucleating particle (INP) number concentrations was found in the measurements, indicating the potentially important role of secondary ice production (SIP) in the clouds. However, the interactions between primary and SIP processes and their relative importance remain unexplored. In this study, we implemented five different ice nucleation schemes as well as physical representations of SIP processes (i.e., droplet shattering during rain freezing, ice-ice collisional break-up, and rime splintering) in the Community Earth System Model version 2 (CESM2). We ran CESM2 in the single column mode for model comparisons with the DOE Atmospheric Radiation Measurement (ARM) Mixed-Phase Arctic Cloud Experiment (M-PACE) observations. We found that the model experiments with aerosol-aware ice nucleation schemes and SIP processes yield the best simulation results for the M-PACE single-layer mixed-phase clouds. We further investigated the relative importance of ice nucleation and SIP to ice number and cloud phase as well as interactions between ice nucleation and SIP in the M-PACE single-layer mixed-phase clouds. Our results show that SIP contributes 80 % to the total ice formation and transforms ∼30 % of pure liquid-phase clouds simulated in the model experiments without considering SIP into mixed-phase clouds. The SIP is not only a result of ice crystals produced from ice nucleation, but also competes with the ice nucleation by reducing the number concentrations of cloud droplets and cloud-borne dust INPs. Conversely, strong ice nucleation also suppresses SIP by glaciating mixed-phase clouds and thereby reducing the amount of precipitation particles (rain and graupel).

Highlights

  • Ice crystals significantly impact microphysical and radiative properties of mixed-phase clouds (Korolev and Isaac, 2003; Korolev et al, 2017; Morrison et al, 2012), which further impact the earth’s energy budgets

  • In the secondary ice production (SIP) experiments with the classical nucleation theory (CNT), N12, and D15 ice nucleation schemes, simulated ice water path (IWP) is increased from 5 to 10 g m−2 and liquid water path (LWP) is decreased from 156 to 97 g m−2 averaged over the MixedPhase Arctic Cloud Experiment (M-PACE) period after considering the SIP

  • The B53, B53_SIP, M92, and M92_SIP produce the largest IWP (∼ 12 g m−2 averaged over the M-PACE period), followed by CNT_SIP, N12_SIP, and D15_SIP (∼ 10 g m−2 averaged over the MPACE period)

Read more

Summary

Introduction

Ice crystals significantly impact microphysical and radiative properties of mixed-phase clouds (Korolev and Isaac, 2003; Korolev et al, 2017; Morrison et al, 2012), which further impact the earth’s energy budgets. Dust is generally considered as the most effective INPs for heterogeneous ice nucleation at temperatures below about −15 ◦C (Hoose et al, 2008; Atkinson et al, 2013; Kanji et al, 2017). SIP processes generate additional ice crystals, often involving the primary ice. Several SIP mechanisms have been suggested: rime splintering, known as the Hallett– Mossop (HM) process, droplet shattering during rain freezing (FR), ice-ice collisional break-up (IIC), and fragmentation during the sublimation of an ice bridge (Field et al, 2017; Korolev et al, 2020). Other microphysical processes, such as rain formation, ice growth, and ice sedimentation are important for mixed-phase cloud properties (Mülmenstädt et al, 2021; Tan and Storelvmo, 2016). Regarding ice-related microphysical processes in mixed-phase clouds, some processes, including riming, accretion, and the Wegener–Bergeron–Findeisen (WBF) process can increase the ice mass mixing ratios while others have no effect on ice Published by Copernicus Publications on behalf of the European Geosciences Union

Objectives
Results
Conclusion

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.