The relative impact of cloud condensation nuclei 
and ice nucleating particle concentrations on phase-partitioning in Arctic Mixed-Phase Stratocumulus Clouds

Solomon, Amy; Boer, Gijs de; Creamean, Jessie M.; McComiskey, Allison; Shupe, Matthew D.; Maahn, Maximilian; Cox, Christopher

doi:10.5194/acp-2018-714

Cited by 8 publications

(12 citation statements)

References 34 publications

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“…However, in neither regime does a perturbation of 10 INP L −1 glaciate the cloud and we still find a mixed-phase regime to be present after 20 h. This finding is consistent with other studies investigating cloud glaciation under INP perturbations (e.g. Solomon et al, 2018).…”

Section: Response To Inp Perturbationssupporting

confidence: 93%

“…crystal growth by deposition increases the total IWC ( Fig. S1), which agrees well with results from Solomon et al (2018). The relative importance of crystal growth by deposition versus immersion freezing in the most perturbed/unperturbed simulation is shown in Fig.…”

Section: Response To Ccn Perturbationssupporting

confidence: 85%

“…of a few CCN from above. This vertical distribution of N drop with a maximum at cloud top in combination with a pronounced in-cloud minimum, as also been simulated by Solomon et al (2018) and therefore does not seem to be unique to our model or setup. Partly compensating for the lower N drop , cloud droplets are 17% (ocean_control) and 47% (ice_control) larger in our simulations as compared to observations (Table 2).…”

Section: Evaluation Of Background Statesupporting

confidence: 74%

“…The absence of a long-term response in cloud properties to soluble aerosol perturbations ranging from 100-1000 cm −3 in magnitude is attributed to the efficient transport of aerosols out of the boundary layer. The accumulation of aerosols above the cloud has also been seen in independent WRF simulations of a different case recently published by Solomon et al (2018). Therefore this mechanism has been seen across models and cases and deserves further investigation.…”

Section: Consistent Response Independent Of Perturbation Injection Pementioning

confidence: 54%

“…Yet the system efficiently returns to an organized cloud structure in a quasi-stationary state after some hours, which is insensitive to the background aerosol concentration. Turbulent mixing of aerosols out of the polluted regions could potentially also dilute the aerosol concentration and decrease the long-term aerosol response, as shown by Berner et al (2015) in large eddy simulations (LES) of ship tracks in the Monterey Bay, or recently by Solomon et al (2018) for MPCs over Oliktok Point, Alaska.…”

Section: Introductionmentioning

confidence: 99%

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Relaxation times of Arctic mixed-phase clouds to short-term aerosol perturbations under different surface forcings

Eirund

Possner

Lohmann

2018

Preprint

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Abstract. The formation and persistence of low lying mixed-phase clouds (MPCs) in the Arctic depends on a multitude of processes, such as surface conditions, the environmental state, air mass advection and the ambient aerosol concentration. In this study, we focus on the relative importance of different aerosol perturbations (cloud condensation nuclei and ice nucleating particles; CCN and INP, respectively) on MPC properties in the central Arctic. To address this topic, we performed high resolution large eddy simulations (LES) using the COSMO model and designed a case study for the Aerosol-Cloud Coupling and Climate Interactions in the Arctic (ACCACIA) campaign in March 2013. Motivated by ongoing sea ice retreat, we additionally contrast the simulated MPC that formed over an open ocean surface and a sea ice surface. We find that surface conditions highly impact cloud dynamics: over sea ice, a rather homogeneous, optically thin, mixed-phase stratus cloud forms. In contrast, the MPC over the open ocean has a stratocumulus-like cloud structure. With cumuli feeding moisture into the stratus layer, the cloud features a higher liquid (LWC) and ice water content (IWC) and has a lifted cloud base compared to the cloud over sea ice. Furthermore, we analyzed the aerosol impact on these two dynamically different regimes. Perturbations in the INP concentration increase the IWC and decrease the LWC consistently in both regimes. The cloud microphysical response to potential CCN perturbations occurs faster in the stratocumulus regime over the ocean, where the increased moisture flux favors rapid cloud droplet formation and growth, leading to an increase in LWC following the aerosol injection. In addition, the IWC increases through increased immersion freezing and subsequent growth by deposition. Over sea ice, the maximum response is delayed by a factor of 2.5 compared to open ocean surface. However, independent of the cloud regime and aerosol perturbation, the cloud regains its original state after at most 12&#8201;h for an aerosol perturbation of 1000&#8201;cm&#8722;3. Cloud microphysical and macrophysical peoperties relax to their unperturbed range, and any aerosol perturbation is efficiently buffered. A substantial fraction of the aerosol is transported out of the boundary layer into the capping inversion, where the supersaturation is insufficient for aerosol activation. Our results are robust across different temperature ranges and insensitive to the aerosol injection period. Based on these results we postulate an efficient aerosol processing and transport mechanism that appears to inhibit any long-term aerosol impact on Arctic MPC properties.

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Section: Response To Inp Perturbationssupporting

confidence: 93%

Section: Response To Ccn Perturbationssupporting

confidence: 85%

Section: Evaluation Of Background Statesupporting

confidence: 74%

Section: Consistent Response Independent Of Perturbation Injection Pementioning

confidence: 54%

Section: Introductionmentioning

confidence: 99%

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Relaxation times of Arctic mixed-phase clouds to short-term aerosol perturbations under different surface forcings

Eirund

Possner

Lohmann

2018

Preprint

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Ice Nucleating Particles Carried From Below a Phytoplankton Bloom to the Arctic Atmosphere

Creamean

Cross

Pickart

et al. 2019

Geophysical Research Letters

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As Arctic temperatures rise at twice the global rate, sea ice is diminishing more quickly than models can predict. Processes that dictate Arctic cloud formation and impacts on the atmospheric energy budget are poorly understood, yet crucial for evaluating the rapidly changing Arctic. In parallel, warmer temperatures afford conditions favorable for productivity of microorganisms that can effectively serve as ice nucleating particles (INPs). Yet the sources of marine biologically derived INPs remain largely unknown due to limited observations. Here we show, for the first time, how biologically derived INPs were likely transported hundreds of kilometers from deep Bering Strait waters and upwelled to the Arctic Ocean surface to become airborne, a process dependent upon a summertime phytoplankton bloom, bacterial respiration, ocean dynamics, and wind‐driven mixing. Given projected enhancement in marine productivity, combined oceanic and atmospheric transport mechanisms may play a crucial role in provision of INPs from blooms to the Arctic atmosphere.

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Wintertime Airborne Measurements of Ice Nucleating Particles in the High Arctic: A Hint to a Marine, Biogenic Source for Ice Nucleating Particles

Hartmann

Adachi

Eppers

et al. 2020

Geophysical Research Letters

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Ice nucleating particles (INPs) affect the radiative properties of cold clouds. Knowledge concerning their concentration above ground level and their potential sources is scarce. Here we present the first highly temperature resolved ice nucleation spectra of airborne samples from an aircraft campaign during late winter in 2018. Most INP spectra featured low concentration levels (<3 · 10−4 L−1 at −15°C). However, we also found INP concentrations of up to 1.8·10−2 L−1 at −15°C and freezing onsets as high as −7.5°C for samples mainly from the marine boundary layer. Shape and onset temperature of the ice nucleation spectra of those samples as well as heat sensitivity hint at biogenic INP. Colocated measurements additionally indicate a local marine influence rather than long‐range transport. Our results suggest that even in late winter above 80°N a local marine source for biogenic INP, which can efficiently nucleate ice at high temperatures, is present.

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The relative impact of cloud condensation nuclei and ice nucleating particle concentrations on phase-partitioning in Arctic Mixed-Phase Stratocumulus Clouds

Cited by 8 publications

References 34 publications

Relaxation times of Arctic mixed-phase clouds to short-term aerosol perturbations under different surface forcings

Relaxation times of Arctic mixed-phase clouds to short-term aerosol perturbations under different surface forcings

Ice Nucleating Particles Carried From Below a Phytoplankton Bloom to the Arctic Atmosphere

Wintertime Airborne Measurements of Ice Nucleating Particles in the High Arctic: A Hint to a Marine, Biogenic Source for Ice Nucleating Particles

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