Development of the DRoplet Ice Nuclei Counter Zurich (DRINCZ): validation and application to field-collected snow samples

David, Robert O.; Cascajo-Castresana, María; Brennan, Killian P.; Rösch, Michael; Els, Nora; Werz, Julia; Weichlinger, Vera; Boynton, Lin S.; Bogler, Sophie; Borduas-Dedekind, Nadine; Marcolli, Claudia; Kanji, Zamin A.

doi:10.5194/amt-12-6865-2019

Cited by 38 publications

(69 citation statements)

References 71 publications

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“…The DRoplet Ice Nuclei Counter Zurich (DRINCZ) is a custom-built instrument that enables the quantification of heterogeneous ice nucleation through immersion freezing (David et al, 2019 well by taking the temperature at the time the image was taken and the instant when 60% of greatest change in light intensity occurred.…”

Section: Ice Nucleation Setupmentioning

confidence: 99%

“…The background was corrected following (Vali, 1971(Vali, , 2019, where the nucleus concentration, Nuc(T), of the background is subtracted from that of the sample and then inverted to reconstruct the corrected FF following Eq. (7) (David et al, 2019).…”

Section: Ice Nucleation Setupmentioning

confidence: 99%

“…To probe the impact of photochemistry on ice nucleation, the field-collected DOM and SRFA were measured in our homebuilt DRoplet Ice Nuclei Counter Zurich (DRINCZ) (David et al, 2019). We report median freezing temperature (T50) values which corresponds to the temperature at which 50% of the wells filled with a DOM solution froze (Figure 2(a)).…”

Section: Photochemistry Affects the Ice Nucleating Ability Of Dommentioning

confidence: 99%

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Photomineralization mechanism changes the ability of dissolved organic matter to activate cloud droplets and to nucleate ice crystals

Borduas-Dedekind¹,

Ossola²,

David³

et al. 2019

Preprint

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Abstract. An organic aerosol particle has a lifetime of approximately one week in the atmosphere during which it will be exposed to sunlight. Yet, the effect of photochemistry on the propensity of organic matter to participate in the initial cloud-forming steps is difficult to predict. In this study, we quantify on a molecular scale the effect of photochemical exposure of naturally occurring dissolved organic matter (DOM) and of a fulvic acid standard on its ability to form mixed-phase clouds, by acting as cloud condensation nuclei (CCN) and by acting as ice nucleating particles (INPs). We find that photochemical processing, equivalent to 4.6 days in the atmosphere, of DOM increases its ability to form cloud droplets by up to a factor of 2.5 but decreases its ability to form ice crystals at a loss rate of &#8722;0.04&#176;CT50 h&#8722;1 of sunlight at ground level. In other words, the ice nucleation activity of photooxidized DOM can require up to 4 degrees colder temperatures for 50&#8201;% of the droplets to activate as ice crystals under immersion freezing conditions. This temperature change could impact the ratio of ice to water droplets within a mixed phase cloud by delaying the onset of glaciation and by increasing the supercooled liquid fraction of the cloud, thereby modifying the radiative properties and the lifetime of the cloud. Concurrently, a photomineralization mechanism was quantified by monitoring the loss of organic carbon and the simultaneous production of organic acids, such as formic, acetic, oxalic and pyruvic acids, CO and CO2. This mechanism explains and predicts the observed increase in CCN and decrease in INP efficiencies. Indeed, we show that photochemical processing can be a dominant atmospheric aging process, impacting CCN and INP efficiencies and concentrations. Photomineralization can thus alter the aerosol-cloud radiative effects of organic matter by modifying the supercooled liquid water-to-ice crystal ratio in mixed-phase clouds with implications for cloud lifetime, precipitation patterns and the hydrological cycle.

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Section: Ice Nucleation Setupmentioning

confidence: 99%

Section: Ice Nucleation Setupmentioning

confidence: 99%

Section: Photochemistry Affects the Ice Nucleating Ability Of Dommentioning

confidence: 99%

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Photomineralization mechanism changes the ability of dissolved organic matter to activate cloud droplets and to nucleate ice crystals

Borduas-Dedekind¹,

Ossola²,

David³

et al. 2019

Preprint

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“…When an INP is immersed in a cloud droplet, freezing occurs on the INP's surface through heterogeneous nucleation when the temperature falls below the threshold value for activation. This immersion freezing mechanism is considered to be the most common pathway to cloud glaciation (de Boer et al, 2010;Westbrook and Illingworth, 2013). Alternatively, cloud droplets may freeze while they come in contact with an INP (contact freezing) or while an INP activates to a cloud droplet (condensation freezing) (Murray et al, 2012;Vali et al, 2015;Kanji et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Protein aggregates nucleate ice: the example of apoferritin

et al. 2020

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Abstract. Biological material has gained increasing attention recently as a source of ice-nucleating particles that may account for cloud glaciation at moderate supercooling. While the ice-nucleation (IN) ability of some bacteria can be related to membrane-bound proteins with epitaxial fit to ice, little is known about the IN-active entities present in biological material in general. To elucidate the potential of proteins and viruses to contribute to the IN activity of biological material, we performed bulk freezing experiments with the newly developed drop freezing assay DRoplet Ice Nuclei Counter Zurich (DRINCZ), which allows the simultaneous cooling of 96 sample aliquots in a chilled ethanol bath. We performed a screening of common proteins, namely the iron storage protein ferritin and its iron-free counterpart apoferritin, the milk protein casein, the egg protein ovalbumin, two hydrophobins, and a yeast ice-binding protein, all of which revealed IN activity with active site densities > 0.1 mg−1 at −10 ∘C. The tobacco mosaic virus, a plant virus based on helically assembled proteins, also proved to be IN active with active site densities increasing from 100 mg−1 at −14 ∘C to 10 000 mg−1 at −20 ∘C. Among the screened proteins, the IN activity of horse spleen ferritin and apoferritin, which form cages of 24 co-assembled protein subunits, proved to be outstanding with active site densities > 10 mg−1 at −5 ∘C. Investigation of the pH dependence and heat resistance of the apoferritin sample confirmed the proteinaceous nature of its IN-active entities but excluded the correctly folded cage monomer as the IN-active species. A dilution series of apoferritin in water revealed two distinct freezing ranges, an upper one from −4 to −11 ∘C and a lower one from −11 to −21 ∘C. Dynamic light scattering measurements related the upper freezing range to ice-nucleating sites residing on aggregates and the lower freezing range to sites located on misfolded cage monomers or oligomers. The sites proved to persist during several freeze–thaw cycles performed with the same sample aliquots. Based on these results, IN activity seems to be a common feature of diverse proteins, irrespective of their function, but arising only rarely, most probably through defective folding or aggregation to structures that are IN active.

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“…The DRoplet Ice Nuclei Counter Zurich (DRINCZ) technique used in this study, as well as the data 15 processing and analysis are described in-depth by David et al (2019). Additional details on the immersion freezing experimental details and on the frozen fraction (FF) analysis and can also be found in the supplemental information.…”

Section: Immersion Freezing Experiments and Data Analysis With Drinczmentioning

confidence: 99%

Ice nucleating particles measured in Swiss alpine snow samples are spatially, temporarily and chemically heterogeneous

Brennan

David

Borduas-Dedekind

2019

Preprint

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Ice nucleating particles (INPs) produce ice from supercooled water droplets through heterogeneous 10 freezing in the atmosphere. Since the concentration of ice crystals affects the radiative properties of clouds as well as precipitation, constraining the liquid water to ice ratio could help reduce aerosol-cloud interaction uncertainties. INPs have been collected at the Jungfraujoch research station (at 3500 m a.s.l.) in central Switzerland; yet spatially diverse data on INP occurrence in the Swiss Alps are scarce and remain uncharacterized. We address this scarcity through our Swiss Alpine snow sample study which 15 took place during the winter of 2018. We collected a total of 88 fallen snow samples across the Alps at different locations, altitudes, terrains, times since last snowfall and depths. The INP concentrations were measured using the homebuilt DRoplet Ice Nuclei Counter Zurich (DRINCZ) and were then compared to spatial, meteorological and physiochemical parameters. We also extend an alternative way of displaying frozen fraction (FF) versus temperature data through visualizing freezing temperatures as a 20boxplot to field collected samples. This plotting method displays the freezing temperature in one dimension, instead of the former two dimensions of FF vs temperature, allowing a condensed display of freezing temperature measurements. In the collected snow samples, large variability in INP occurrence was found, even for samples collected 10 m apart on a plain and 1 m apart in depth. Furthermore, undiluted samples had INP concentrations ranging between 1 and 100 INP ml -1 of snow water over a 25 temperature range of −5 to −19 C. From this field-collected data set, we parameterize the INP concentrations per milliliter of meltwater as a function of temperature with the following equation * ( ) = − . − . , comparing well with previously reported precipitation data presented in Petters and Wright, 2015. 30 When assuming a cloud water content of 0.4 g m -3 and a critical INP concentration for glaciation of 10 m -3 , the majority of the snow precipitated from clouds with glaciation temperatures between −5 and −20 °C. Based on the observed variability in INP concentrations, we conclude that studies conducted at the high-altitude research station Jungfraujoch are representative for INP measurements in the Swiss Alps. Furthermore, the INP concentration precipitation estimates allow us to extrapolate the 35 concentrations to a cloud frozen fraction. Indeed, this approach for estimating the liquid water to ice ratio in mixed phase clouds compares well with aircraft measurements, ground-based lidar and satellite retrievals of cloud frozen fractions. In all, the generated parameterization for INP concentrations in meltwater could help estimate cloud glaciation temperatures.

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Development of the DRoplet Ice Nuclei Counter Zurich (DRINCZ): validation and application to field-collected snow samples

Cited by 38 publications

References 71 publications

Photomineralization mechanism changes the ability of dissolved organic matter to activate cloud droplets and to nucleate ice crystals

Photomineralization mechanism changes the ability of dissolved organic matter to activate cloud droplets and to nucleate ice crystals

Protein aggregates nucleate ice: the example of apoferritin

Ice nucleating particles measured in Swiss alpine snow samples are spatially, temporarily and chemically heterogeneous

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