The effect of secondary ice production parameterization on the
simulation of a cold frontal rainband

Sullivan, Sylvia; Barthlott, Christian; Crosier, Jonathan; Nenes, Athanasios; Hoose, Corinna

doi:10.5194/acp-2018-502

Cited by 4 publications

(6 citation statements)

References 38 publications

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“…The latter two studies created the basis for a mechanistic description of BR (e.g., Phillips et al, 2017a;Sullivan et al, 2018a;Sotiropoulou et al, 2020). Parameterizations of BR have recently been implemented in small-scale (Fridlind et al, 2007;Phillips et al, 2017a, b;Sotiropoulou et al, 2020Sotiropoulou et al, , 2021bSullivan et al, 2018a;Yano and Phillips, 2011;Yano et al, 2016), mesoscale (Hoarau et al, 2018;Sullivan et al, 2018b;Qu et al, 2020;Sotiropoulou et al, 2021a;Dedekind et al, 2021), and global climate models (Zhao and Liu, 2021a), each with their own approach towards BR description.…”

Section: Introductionmentioning

confidence: 99%

Secondary ice production processes in wintertime alpine mixed-phase clouds

Georgakaki¹,

Sotiropoulou

Vignon

et al. 2022

Atmos. Chem. Phys.

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Abstract. Observations of orographic mixed-phase clouds (MPCs) have long shown that measured ice crystal number concentrations (ICNCs) can exceed the concentration of ice nucleating particles by orders of magnitude. Additionally, model simulations of alpine clouds are frequently found to underestimate the amount of ice compared with observations. Surface-based blowing snow, hoar frost, and secondary ice production processes have been suggested as potential causes, but their relative importance and persistence remains highly uncertain. Here we study ice production mechanisms in wintertime orographic MPCs observed during the Cloud and Aerosol Characterization Experiment (CLACE) 2014 campaign at the Jungfraujoch site in the Swiss Alps with the Weather Research and Forecasting model (WRF). Simulations suggest that droplet shattering is not a significant source of ice crystals at this specific location, but breakups upon collisions between ice particles are quite active, elevating the predicted ICNCs by up to 3 orders of magnitude, which is consistent with observations. The initiation of the ice–ice collisional breakup mechanism is primarily associated with the occurrence of seeder–feeder events from higher precipitating cloud layers. The enhanced aggregation of snowflakes is found to drive secondary ice formation in the simulated clouds, the role of which is strengthened when the large hydrometeors interact with the primary ice crystals formed in the feeder cloud. Including a constant source of cloud ice crystals from blowing snow, through the action of the breakup mechanism, can episodically enhance ICNCs. Increases in secondary ice fragment generation can be counterbalanced by enhanced orographic precipitation, which seems to prevent explosive multiplication and cloud dissipation. These findings highlight the importance of secondary ice and seeding mechanisms – primarily falling ice from above and, to a lesser degree, blowing ice from the surface – which frequently enhance primary ice and determine the phase state and properties of MPCs.

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Section: Introductionmentioning

confidence: 99%

Secondary ice production processes in wintertime alpine mixed-phase clouds

Georgakaki¹,

Sotiropoulou

Vignon

et al. 2022

Atmos. Chem. Phys.

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“…In this temperature range, some biological aerosols originating from soil, plants, and the ocean are found to be efficient ice-nucleating particles that can trigger ice nucleation above −10 • C (10-13). However, these efficient ice-nucleating particles are rare, suggesting that secondary ice production (SIP) is important (14).…”

mentioning

confidence: 99%

New insights into ice multiplication using remote-sensing observations of slightly supercooled mixed-phase clouds in the Arctic

Luke

Yang

Kollias

et al. 2021

Proc. Natl. Acad. Sci. U.S.A.

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Secondary ice production (SIP) can significantly enhance ice particle number concentrations in mixed-phase clouds, resulting in a substantial impact on ice mass flux and evolution of cold cloud systems. SIP is especially important at temperatures warmer than −10 ○C, for which primary ice nucleation lacks a significant number of efficient ice nucleating particles. However, determining the climatological significance of SIP has proved difficult using existing observational methods. Here we quantify the long-term occurrence of secondary ice events and their multiplication factors in slightly supercooled clouds using a multisensor, remote-sensing technique applied to 6 y of ground-based radar measurements in the Arctic. Further, we assess the potential contribution of the underlying mechanisms of rime splintering and freezing fragmentation. Our results show that the occurrence frequency of secondary ice events averages to <10% over the entire period. Although infrequent, the events can have a significant impact in a local region when they do occur, with up to a 1,000-fold enhancement in ice number concentration. We show that freezing fragmentation, which appears to be enhanced by updrafts, is more efficient for SIP than the better-known rime-splintering process. Our field observations are consistent with laboratory findings while shedding light on the phenomenon and its contributing factors in a natural environment. This study provides critical insights needed to advance parameterization of SIP in numerical simulations and to design future laboratory experiments.

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“…Several numerical studies investigated the roles of different SIP mechanisms in ice particle production in different types of clouds in different regions (Phillips et al, 2017a(Phillips et al, , 2018Sullivan et al, 2018a;Fu et al, 2019;Sotiropoulou et al, 2020Sotiropoulou et al, , 2021. Phillips et al (2017a) indicated that the average ice number concentration at temperatures between ∼ 0 and −30 • C increased by 1 to 2 orders of magnitude with the inclusion of fragmentation in iceice collisions in a cloud-resolving model simulating a multicellular convective storm observed over the US high plains during the Severe Thunderstorm Electrification and Precip-itation Study (STEPS).…”

Section: Introductionmentioning

confidence: 99%

Microphysical processes producing high ice water contents (HIWCs) in tropical convective clouds during the HAIC-HIWC field campaign: dominant role of secondary ice production

Huang

McFarquhar

et al. 2022

Atmos. Chem. Phys.

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Abstract. High ice water content (HIWC) regions in tropical deep convective clouds, composed of high concentrations of small ice crystals, were not reproduced by Weather Research and Forecasting (WRF) model simulations at 1 km horizontal grid spacing using four different bulk microphysics schemes (i.e., the WRF single‐moment 6‐class microphysics scheme (WSM6), the Morrison scheme and the Predicted Particle Properties (P3) scheme with one- and two-ice options) for conditions encountered during the High Altitude Ice Crystals (HAIC) and HIWC experiment. Instead, overestimates of radar reflectivity and underestimates of ice number concentrations were realized. To explore formation mechanisms for large numbers of small ice crystals in tropical convection, a series of quasi-idealized WRF simulations varying the model resolution, aerosol profile, and representation of secondary ice production (SIP) processes are conducted based on an observed radiosonde released at Cayenne during the HAIC-HIWC field campaign. The P3 two-ice category configuration, which has two “free” ice categories to represent all ice-phase hydrometeors, is used. Regardless of the horizontal grid spacing or aerosol profile used, without including SIP processes the model produces total ice number concentrations about 2 orders of magnitude less than observed at −10 ∘C and about an order of magnitude less than observed at −30 ∘C but slightly overestimates the total ice number concentrations at −45 ∘C. Three simulations including one of three SIP mechanisms separately (i.e., the Hallett–Mossop mechanism, fragmentation during ice–ice collisions, and shattering of freezing droplets) also do not replicate observed HIWCs, with the results of the simulation including shattering of freezing droplets most closely resembling the observations. The simulation including all three SIP processes produces HIWC regions at all temperature levels, remarkably consistent with the observations in terms of ice number concentrations and radar reflectivity, which is not replicated using the original P3 two-ice category configuration. This simulation shows that primary ice production plays a key role in generating HIWC regions at temperatures <-40 ∘C, shattering of freezing droplets dominates ice particle production in HIWC regions at temperatures between −15 and 0 ∘C during the early stage of convection, and fragmentation during ice–ice collisions dominates at temperatures between −15 and 0 ∘C during the later stage of convection and at temperatures between −40 and −20 ∘C over the whole convection period. This study confirms the dominant role of SIP processes in the formation of numerous small crystals in HIWC regions.

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The effect of secondary ice production parameterization on the simulation of a cold frontal rainband

Cited by 4 publications

References 38 publications

Secondary ice production processes in wintertime alpine mixed-phase clouds

Secondary ice production processes in wintertime alpine mixed-phase clouds

New insights into ice multiplication using remote-sensing observations of slightly supercooled mixed-phase clouds in the Arctic

Microphysical processes producing high ice water contents (HIWCs) in tropical convective clouds during the HAIC-HIWC field campaign: dominant role of secondary ice production

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