scholarly journals Ice nucleation and its effect on the atmospheric transport of fungal spores from the classes <i>Agaricomycetes</i>, <i>Ustilaginomycetes</i>, and <i>Eurotiomycetes</i>

2014 ◽  
Vol 14 (4) ◽  
pp. 5013-5059 ◽  
Author(s):  
D. I. Haga ◽  
S. M. Burrows ◽  
R. Iannone ◽  
M. J. Wheeler ◽  
R. Mason ◽  
...  
Keyword(s):  
Transport Model ◽  
Atmospheric Transport ◽  
Fungal Spores ◽  
Ice Nucleation ◽  
Mixed Phase ◽  
Cumulative Number ◽  
Near Surface ◽  
Ice Nuclei ◽  
Wide Range ◽  
Mixed Phase Clouds

Abstract. Ice nucleation on fungal spores may affect the frequency and properties of ice and mixed-phase clouds. We studied the ice nucleation properties of 12 different species of fungal spores chosen from three classes: Agaricomycetes, Ustilaginomycetes, and Eurotiomycetes. Agaricomycetes include many types of mushroom species and are cosmopolitan. Ustilaginomycetes are agricultural pathogens and have caused widespread damage to crops. Eurotiomycetes are found on all types of decaying material and include important human allergens. We focused on these classes since they are thought to be abundant in the atmosphere and because there is very little information on the ice nucleation ability of these classes of spores in the literature. All of the fungal spores investigated were found to cause freezing of water droplets at temperatures warmer than homogeneous freezing. The cumulative number of ice nuclei per spore was 0.001 at temperatures between −19 °C and −29 °C, 0.01 between −25.5 °C and −31 °C, and 0.1 between −26 °C and −36 °C. On average, the order of ice nucleating ability for these spores is Ustilaginomycetes > Agaricomycetes &amp;simeq; Eurotiomycetes. We show that at temperatures below −20 °C, all of the fungal spores studied here are less efficient ice nuclei compared to Asian mineral dust on a per surface area basis. We used our new freezing results together with data in the literature to compare the freezing temperatures of spores from the phyla Basidiomycota and Ascomycota, which together make up 98% of known fungal species found on Earth. The data show that within both phyla (Ascomycota and Basidiomycota) there is a wide range of freezing properties, and also that the variation within a phylum is greater than the variation between the average freezing properties of the phyla. Using a global chemistry–climate transport model, we investigated whether ice nucleation on the studied spores, followed by precipitation, can influence the atmospheric transport and global distributions of these spores in the atmosphere. Simulations show that inclusion of ice nucleation scavenging of these fungal spores in mixed-phase clouds can decrease the annual mean concentrations of fungal spores in near-surface air over the oceans and polar regions and decrease annual mean mixing ratios in the upper troposphere.

scholarly journals Ice nucleation by fungal spores from the classes <i>Agaricomycetes</i>, <i>Ustilaginomycetes</i>, and <i>Eurotiomycetes</i>, and the effect on the atmospheric transport of these spores

2014 ◽  
Vol 14 (16) ◽  
pp. 8611-8630 ◽  
Author(s):  
D. I. Haga ◽  
S. M. Burrows ◽  
R. Iannone ◽  
M. J. Wheeler ◽  
R. H. Mason ◽  
...  
Keyword(s):  
Transport Model ◽  
Atmospheric Transport ◽  
Fungal Spores ◽  
Ice Nucleation ◽  
Polar Regions ◽  
Cumulative Number ◽  
Mushroom Species ◽  
Near Surface ◽  
Ice Nuclei ◽  
Wide Range

Abstract. We studied the ice nucleation properties of 12 different species of fungal spores chosen from three classes: Agaricomycetes, Ustilaginomycetes, and Eurotiomycetes. Agaricomycetes include many types of mushroom species and are widely distributed over the globe. Ustilaginomycetes are agricultural pathogens and have caused widespread damage to crops. Eurotiomycetes are found on all types of decaying material and include important human allergens. We focused on these classes because they are thought to be abundant in the atmosphere and because there is very little information on the ice nucleation ability of these classes of spores in the literature. All of the fungal spores investigated contained some fraction of spores that serve as ice nuclei at temperatures warmer than homogeneous freezing. The cumulative number of ice nuclei per spore was 0.001 at temperatures between −19 °C and −29 °C, 0.01 between −25.5 °C and −31 °C, and 0.1 between −26 °C and −31.5 °C. On average, the order of ice nucleating ability for these spores is Ustilaginomycetes > Agaricomycetes ≃ Eurotiomycetes. The freezing data also suggests that, at temperatures ranging from −20 °C to −25 °C, all of the fungal spores studied here are less efficient ice nuclei compared to Asian mineral dust on a per surface area basis. We used our new freezing results together with data in the literature to compare the freezing temperatures of spores from the phyla Basidiomycota and Ascomycota, which together make up 98% of known fungal species found on Earth. The data show that within both phyla (Ascomycota and Basidiomycota), there is a wide range of freezing properties, and also that the variation within a phylum is greater than the variation between the average freezing properties of the phyla. Using a global chemistry–climate transport model, we investigated whether ice nucleation on the studied spores, followed by precipitation, can influence the transport and global distributions of these spores in the atmosphere. Simulations suggest that inclusion of ice nucleation scavenging of these fungal spores in mixed-phase clouds can decrease the annual mean concentrations of fungal spores in near-surface air over the oceans and polar regions, and decrease annual mean concentrations in the upper troposphere.

Towards a molecular-based parameterization of the ice nucleation activity of biological macromolecules and its implications for aerosol-cloud interactions

2021 ◽  
Author(s):  
Minghui Zhang ◽  
Amina Khaled ◽  
Pierre Amato ◽  
Anne-Marie Delort ◽  
Barbara Ervens
Keyword(s):  
Fungal Spores ◽  
Chemical Properties ◽  
Active Surface ◽  
Ice Nucleation ◽  
Mixed Phase ◽  
Biological Macromolecules ◽  
Cloud Properties ◽  
Nucleation Activity ◽  
Mixed Phase Clouds ◽  
Ice Nucleation Activity

&lt;p&gt;Primary biological aerosol particles (PBAPs) play an important role in mixed-phase clouds as they nucleate ice even at temperatures of T &gt; -10 &amp;#176;C. Current parameterizations of PBAP ice nucleation are based on ice nucleation active surface site (INAS) densities that are derived from freezing experiments. However, only a small fraction of the PBAP surface is responsible for their ice nucleation activity, such as proteins of bacteria cells, fungal spores, pollen polysaccharides and other (unidentified) macromolecules. Based on literature data, we refine the INAS density parameterizations by further parameters:&lt;/p&gt;&lt;p&gt;1) We demonstrate that the ice nucleation activity of such individual macromolecules is much higher than that of PBAPs. It can be shown that INAS of PBAPs can be scaled by the surface fraction of these ice-nucleating molecules.&lt;/p&gt;&lt;p&gt;2) Previous studies suggested that ice nucleation activity tends to be higher for larger macromolecules and their aggregates. We show that these trends hold true for various groups of macromolecules that comprise PBAPs.&lt;/p&gt;&lt;p&gt;Based on these trends, we suggest a more refined parameterization for ice-nucleating macromolecules in different types of PBAPs and even for different species of bacteria, fungi, and pollen. This new parameterization can be considered a step towards a molecular-based approach to predict the ice nucleation activity of the macromolecules in PBAPs based on their biological and chemical properties.&lt;/p&gt;&lt;p&gt;We implement both the traditional INAS parameterization for complete PBAPs and our parameterization for individual molecules in an adiabatic cloud parcel model. The extent will be discussed to which the two parameterizations result in different cloud properties of mixed-phase clouds.&lt;/p&gt;

scholarly journals Possible roles of ice nucleation mode and ice nuclei depletion in the extended lifetime of Arctic mixed-phase clouds

2005 ◽  
Vol 32 (18) ◽  
pp. n/a-n/a ◽  
Author(s):  
Hugh Morrison ◽  
Matthew D. Shupe ◽  
James O. Pinto ◽  
Judith A. Curry
Keyword(s):  
Ice Nucleation ◽  
Mixed Phase ◽  
Nucleation Mode ◽  
Ice Nuclei ◽  
Mixed Phase Clouds

scholarly journals The potential influence of Asian and African mineral dust on ice, mixed-phase and liquid water clouds

2010 ◽  
Vol 10 (18) ◽  
pp. 8649-8667 ◽  
Author(s):  
A. Wiacek ◽  
T. Peter ◽  
U. Lohmann
Keyword(s):  
Liquid Water ◽  
Mineral Dust ◽  
Dust Emission ◽  
Ice Nucleation ◽  
Transport Processes ◽  
Mixed Phase ◽  
Ice Clouds ◽  
Cloud Processing ◽  
Ice Nuclei ◽  
Mixed Phase Clouds

Abstract. This modelling study explores the availability of mineral dust particles as ice nuclei for interactions with ice, mixed-phase and liquid water clouds, also tracking the particles' history of cloud-processing. We performed 61 320 one-week forward trajectory calculations originating near the surface of major dust emitting regions in Africa and Asia using high-resolution meteorological analysis fields for the year 2007. Dust-bearing trajectories were assumed to be those coinciding with known dust emission seasons, without explicitly modelling dust emission and deposition processes. We found that dust emissions from Asian deserts lead to a higher potential for interactions with high ice clouds, despite being the climatologically much smaller dust emission source. This is due to Asian regions experiencing significantly more ascent than African regions, with strongest ascent in the Asian Taklimakan desert at ~25%, ~40% and 10% of trajectories ascending to 300 hPa in spring, summer and fall, respectively. The specific humidity at each trajectory's starting point was transported in a Lagrangian manner and relative humidities with respect to water and ice were calculated in 6-h steps downstream, allowing us to estimate the formation of liquid, mixed-phase and ice clouds. Downstream of the investigated dust sources, practically none of the simulated air parcels reached conditions of homogeneous ice nucleation (T≲−40 °C) along trajectories that have not experienced water saturation first. By far the largest fraction of cloud forming trajectories entered conditions of mixed-phase clouds, where mineral dust will potentially exert the biggest influence. The majority of trajectories also passed through atmospheric regions supersaturated with respect to ice but subsaturated with respect to water, where so-called "warm ice clouds" (T≳−40 °C) theoretically may form prior to supercooled water or mixed-phase clouds. The importance of "warm ice clouds" and the general influence of dust in the mixed-phase cloud region are highly uncertain due to both a considerable scatter in recent laboratory data from ice nucleation experiments, which we briefly review in this work, and due to uncertainties in sub-grid scale vertical transport processes unresolved by the present trajectory analysis. For "classical" cirrus-forming temperatures (T≲−40 °C), our results show that only mineral dust ice nuclei that underwent mixed-phase cloud-processing, most likely acquiring coatings of organic or inorganic material, are likely to be relevant. While the potential paucity of deposition ice nuclei shown in this work dimishes the possibility of deposition nucleation, the absence of liquid water droplets at T≲−40 °C makes the less explored contact freezing mechanism (involving droplet collisions with bare ice nuclei) highly inefficient. These factors together indicate the necessity of further systematic studies of immersion mode ice nucleation on mineral dust suspended in atmospherically relevant coatings.

scholarly journals The effects of hygroscopicity of fossil fuel combustion aerosols on mixed-phase clouds

2012 ◽  
Vol 12 (8) ◽  
pp. 19987-20006
Author(s):  
Y. Yun ◽  
J. E. Penner ◽  
O. Popovicheva
Keyword(s):  
Fossil Fuel ◽  
Laboratory Data ◽  
Ice Nucleation ◽  
Mixed Phase ◽  
Liquid Water Path ◽  
Anthropogenic Forcing ◽  
Soot Particles ◽  
Cloud Forcing ◽  
Ice Nuclei ◽  
Mixed Phase Clouds

Abstract. Fossil fuel black carbon and organic matter (ffBC/OM) are often emitted together with sulfate, which coats the surface of these particles and changes their hygroscopicity. Observational studies show that the hygroscopicity of soot particles can modulate their ice nucleation ability. To address this, we implemented a scheme that uses 3 levels of soot hygroscopicity (hydrophobic, hydrophilic and hygroscopic) and used laboratory data to specify their ice nuclei abilities. The new scheme results in significant changes to anthropogenic forcing in mixed-phase clouds. The net forcing in off-line studies varies from 0.111 to 1.059 W m−2 depending on the ice nucleation capability of hygroscopic soot particles. The total anthropogenic cloud forcing and whole-sky forcing with the new scheme is 0.06 W m−2 and −2.45 W m−2, respectively, but could be more positive if hygroscopic soot particles are allowed to nucleate ice particles. The change in liquid water path dominates the anthropogenic forcing in mixed-phase clouds.

scholarly journals Twin-plate Ice Nucleation Assay (TINA) with infrared detection for high-throughput droplet freezing experiments with biological ice nuclei in laboratory and field samples

2018 ◽  
Vol 11 (11) ◽  
pp. 6327-6337 ◽  
Author(s):  
Anna T. Kunert ◽  
Mark Lamneck ◽  
Frank Helleis ◽  
Ulrich Pöschl ◽  
Mira L. Pöhlker ◽  
...  
Keyword(s):  
Pseudomonas Syringae ◽  
High Throughput ◽  
Atmospheric Aerosols ◽  
Cooling System ◽  
Infrared Detector ◽  
Ice Nucleation ◽  
Cumulative Number ◽  
Ice Nuclei ◽  
Wide Range ◽  
Field Samples

Abstract. For efficient analysis and characterization of biological ice nuclei under immersion freezing conditions, we developed the Twin-plate Ice Nucleation Assay (TINA) for high-throughput droplet freezing experiments, in which the temperature profile and freezing of each droplet is tracked by an infrared detector. In the fully automated setup, a couple of independently cooled aluminum blocks carrying two 96-well plates and two 384-well plates, respectively, are available to study ice nucleation and freezing events simultaneously in hundreds of microliter-range droplets (0.1–40 µL). A cooling system with two refrigerant circulation loops is used for high-precision temperature control (uncertainty <0.2 K), enabling measurements over a wide range of temperatures (∼ 272–233 K) at variable cooling rates (up to 10 K min−1). The TINA instrument was tested and characterized in experiments with bacterial and fungal ice nuclei (IN) from Pseudomonas syringae (Snomax®) and Mortierella alpina, exhibiting freezing curves in good agreement with literature data. Moreover, TINA was applied to investigate the influence of chemical processing on the activity of biological IN, in particular the effects of oxidation and nitration reactions. Upon exposure of Snomax® to O3 and NO2, the cumulative number of IN active at 270–266 K decreased by more than 1 order of magnitude. Furthermore, TINA was used to study aqueous extracts of atmospheric aerosols, simultaneously investigating a multitude of samples that were pre-treated in different ways to distinguish different kinds of IN. For example, heat treatment and filtration indicated that most biological IN were larger than 5 µm. The results confirm that TINA is suitable for high-throughput experiments and efficient analysis of biological IN in laboratory and field samples.

scholarly journals Modelling mixed-phase clouds with large-eddy model UCLALES-SALSA

2020 ◽  
Author(s):  
Jaakko Ahola ◽  
Hannele Korhonen ◽  
Juha Tonttila ◽  
Sami Romakkaniemi ◽  
Harri Kokkola ◽  
...  
Keyword(s):  
Liquid Layer ◽  
Cloud Model ◽  
Ice Nucleation ◽  
Mixed Phase ◽  
Ice Nuclei ◽  
Active Particles ◽  
Large Eddy ◽  
Ice Microphysics ◽  
Intercomparison Study ◽  
Mixed Phase Clouds

&lt;p&gt;We have extended the large-eddy model UCLALES-SALSA (Tonttila et al., 2017) to include formation of ice and mixed-phase clouds. The model has exceptionally detailed aerosol description for both aerosol number and chemical composition. We confirmed the accuracy of newly implemented ice microphysics with a comparison to a previous mixed-phase cloud model intercomparison study.&lt;/p&gt;&lt;p&gt;In a further simulation the model captured the typical layered structure of Arctic mixed-phase clouds: a liquid layer near cloud top and ice within and below the liquid layer. The simulation also demonstrated how larger droplets froze first. Moreover, the simulation showed realistic freezing rates of droplets within the vertical cloud structure. These characteristics were possible to capture with a heterogeneous ice nucleation scheme, where also ice nucleating particles (INP) are prognosed. Here, dust containing particles acted as INPs.&lt;/p&gt;&lt;p&gt;The prognostic simulation showed the importance of the self-adjustment of ice nucleation active particles. This is in good agreement with an observational study where resilient mixed-phase clouds are seen together with relatively high ice nuclei concentrations.&lt;/p&gt;&lt;p&gt;The implemented detailed sectional ice microphysics with prognostic aerosols is essentially important in reproducing the characteristics of mixed-phase clouds. The manuscript of this study is submitted for publication.&lt;/p&gt;

scholarly journals Condensed-phase biogenic–anthropogenic interactions with implications for cold cloud formation

2017 ◽  
Vol 200 ◽  
pp. 165-194 ◽  
Author(s):  
Joseph C. Charnawskas ◽  
Peter A. Alpert ◽  
Andrew T. Lambe ◽  
Thomas Berkemeier ◽  
Rachel E. O’Brien ◽  
...  
Keyword(s):  
Freezing Temperature ◽  
Organic Aerosol ◽  
Ice Nucleation ◽  
Mixed Phase ◽  
Cloud Formation ◽  
Fossil Fuel Combustion ◽  
Soot Particles ◽  
Ice Nuclei ◽  
Deliquescence Relative Humidity ◽  
Homogeneous Freezing

Anthropogenic and biogenic gas emissions contribute to the formation of secondary organic aerosol (SOA). When present, soot particles from fossil fuel combustion can acquire a coating of SOA. We investigate SOA–soot biogenic–anthropogenic interactions and their impact on ice nucleation in relation to the particles’ organic phase state. SOA particles were generated from the OH oxidation of naphthalene, α-pinene, longifolene, or isoprene, with or without the presence of sulfate or soot particles. Corresponding particle glass transition (Tg) and full deliquescence relative humidity (FDRH) were estimated using a numerical diffusion model. Longifolene SOA particles are solid-like and all biogenic SOA sulfate mixtures exhibit a core–shell configuration (i.e.a sulfate-rich core coated with SOA). Biogenic SOA with or without sulfate formed ice at conditions expected for homogeneous ice nucleation, in agreement with respectiveTgand FDRH. α-pinene SOA coated soot particles nucleated ice above the homogeneous freezing temperature with soot acting as ice nuclei (IN). At lower temperatures the α-pinene SOA coating can be semisolid, inducing ice nucleation. Naphthalene SOA coated soot particles acted as ice nuclei above and below the homogeneous freezing limit, which can be explained by the presence of a highly viscous SOA phase. Our results suggest that biogenic SOA does not play a significant role in mixed-phase cloud formation and the presence of sulfate renders this even less likely. However, anthropogenic SOA may have an enhancing effect on cloud glaciation under mixed-phase and cirrus cloud conditions compared to biogenic SOA that dominate during pre-industrial times or in pristine areas.

scholarly journals The effects of hygroscopicity on ice nucleation of fossil fuel combustion aerosols in mixed-phase clouds

2013 ◽  
Vol 13 (8) ◽  
pp. 4339-4348 ◽  
Author(s):  
Y. Yun ◽  
J. E. Penner ◽  
O. Popovicheva
Keyword(s):  
Fossil Fuel ◽  
Laboratory Data ◽  
Ice Nucleation ◽  
Mixed Phase ◽  
Liquid Water Path ◽  
Anthropogenic Forcing ◽  
Soot Particles ◽  
Model Studies ◽  
Ability To Act ◽  
Mixed Phase Clouds

Abstract. Fossil fuel black carbon and organic matter (ffBC/OM) are often emitted together with sulfate, which coats the surface of these particles and changes their hygroscopicity. Observational studies at cirrus temperatures (≈−40 °C) show that the hygroscopicity of soot particles can modulate their ice nucleation ability. Here, we implement a scheme for 3 categories of soot (hydrophobic, hydrophilic and hygroscopic) on the basis of laboratory data and specify their ability to act as ice nuclei at mixed-phase temperatures by extrapolating the observations using a published deposition/condensation/immersion freezing parameterization. The new scheme results in significant changes to anthropogenic forcing in mixed-phase clouds. The net forcing in our offline model studies varies from 0.111 to 1.059 W m−2 depending on the ice nucleation capability of hygroscopic soot particles. The total anthropogenic cloud forcing and whole-sky forcing with the new scheme are 0.06 W m−2 and −2.45 W m−2, respectively, but could be more positive (by about 1.17 W m−2) if hygroscopic soot particles are allowed to nucleate ice particles. The change in liquid water path dominates the anthropogenic forcing in mixed-phase clouds.

scholarly journals Effects of Wegener-Bergeron-Findeisen Process on Global Black Carbon Distribution

2016 ◽  
Author(s):  
Ling Qi ◽  
Qinbin Li ◽  
Cenlin He ◽  
Xin Wang ◽  
Jianping Huang
Keyword(s):  
Transport Model ◽  
Liquid Water Content ◽  
Mixed Phase ◽  
The Arctic ◽  
Deposition Flux ◽  
Chemical Transport Model ◽  
Washout Ratio ◽  
Lower Temperature ◽  
Mixed Phase Clouds ◽  
Scavenging Efficiency

Abstract. We systematically investigate the effects of Wegener-Bergeron-Findeisen (WBF) on BC scavenging efficiency, surface BCair, deposition flux, concentration in snow (BCsnow, ng g−1), and washout ratio using a global 3D chemical transport model (GEOS-Chem). We differentiate riming- versus WBF-dominated in-cloud scavenging based on liquid water content (LWC) and temperature. Specifically, we relate WBF to either temperature or ice mass fraction (IMF) in mixed-phase clouds. We find that at Jungfraujoch, Switzerland and Abisko, Sweden, where WBF dominates, the discrepancies of simulated BC scavenging efficiency and washout ratio are significantly reduced (from a factor of 3 to 10 % and from a factor of 4–5 to a factor of two). However, at Zeppelin, Norway, where riming dominates, simulation of BC scavenging efficiency, BCair, and washout ratio become worse (relative to observations) when WBF is included. There is thus an urgent need for extensive observations to distinguish and characterize riming- versus WBF-dominated aerosol scavenging in mixed-phase clouds and the associated BC scavenging efficiency. We find the reduction resulting from WBF to global BC scavenging efficiency varies substantially, from 8 % in the tropics to 76 % in the Arctic. The resulting annual mean BCair increases by up to 156 % at high altitudes and at northern high latitudes because of lower temperature and higher IMF. Overall, WBF halves the model-observation discrepancy (from −65 % to −30 %) of BCair across North America, Europe, China and the Arctic. Globally WBF increases BC burden from 0.22 to 0.29–0.35 mg m−2 yr−1, which partially explains the gap between observed and previous model simulated BC burdens over land. In addition, WBF significantly increases BC lifetime from 5.7 days to ~8 days. Additionally, WBF results in a significant redistribution of BC deposition in source and remote regions. Specifically, it lowers BC wet deposition (by 37–63 % at northern mid-latitudes and by 21–29 % in the Arctic) while increases dry deposition (by 3–16 % at mid-latitudes and by 81–159 % in the Arctic). The resulting total BC deposition is lower at mid-latitudes (by 12–34 %) but higher in the Arctic (by 2–29 %). We find that WBF decreases BCsnow at mid-latitudes (by ~15 %) but increases it in the Arctic (by 26 %) while improving model comparisons with observations. In addition, WBF dramatically reduces the model-observation discrepancy of washout ratios in winter (from a factor of 16 to 4). The remaining discrepancies in BCair, BCsnow and BC washout ratios suggest that in-cloud removal in mixed-phased clouds is likely still excessive over land.

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