The ice nucleating ability of pollen

Diehl, K.; Quick, C. R.; Matthias‐Maser, Sabine; Mitra, Subir K.; Jaenicke, R.

doi:10.1016/s0169-8095(01)00091-6

Cited by 178 publications

(70 citation statements)

References 32 publications

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“…Although several PBAPs have been identified as potential CCN (Ariya et al, 2009;Sun & Ariya, 2006), the exact contribution of PBAP to CCN numbers is yet to be constrained. Specifically among these different categories of PBAP, anemophilous or wind-driven pollen has been identified as a potential natural source of CCN (Griffiths et al, 2012), ice nucleating particles (Diehl et al, 2001), and giant CCN (Pope, 2010). While pollen grains may not contribute substantially to global CCN concentrations at ambient concentrations of 10-10 3 grains per cubic meter (Despres et al, 2012), there is growing evidence that regional counts may be higher (10 4 grains per cubic meter) and pollen grains may be transported farther than previously thought (Williams & Després, 2017).…”

Section: Citationmentioning

confidence: 99%

Pollen Rupture and Its Impact on Precipitation in Clean Continental Conditions

Wozniak¹,

Solmon

Steiner

2018

Geophysical Research Letters

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Pollen grains emitted from vegetation can rupture, releasing subpollen particles (SPPs) as fine atmospheric particulates. Previous laboratory research demonstrates potential for SPPs as efficient cloud condensation nuclei (CCN). We develop the first model of atmospheric pollen grain rupture and implement the mechanism in regional climate model simulations over spring pollen season in the United States with a CCN‐dependent moisture scheme. The source of SPPs (surface or in‐atmosphere) depends on region and sometimes season, due to the distribution of relative humidity and rain. Simulated concentrations of SPPs are approximately 1–10 or 1–1,000 cm−3, depending on the number of SPPs produced per pollen grain (nspg). Lower nspg (103) produces a negligible effect on precipitation, but high nspg (106) in clean continental CCN background concentrations (100 CCN per cubic centimeter) shows that SPPs suppress average seasonal precipitation by 32% and shift rates from heavy to light while increasing dry days. This effect is smaller (2% reduction) for polluted air.

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Section: Citationmentioning

confidence: 99%

Pollen Rupture and Its Impact on Precipitation in Clean Continental Conditions

Wozniak¹,

Solmon

Steiner

2018

Geophysical Research Letters

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“…Biological ice nuclei (cells of microorganisms such as bacteria [91], pollen [92,93], or biogenic particles produced from organic matter [94,95]) have the potential to initiate heterogeneous ice nucleation in clouds and create precipitation. Moreover, they likely are the most abundant atmospheric ice nuclei covering nucleation temperatures between −2 • C and −10 • C [3], a temperature range critical for secondary ice formation [96].…”

Section: Identifying and Quantifying Contributions Of Biological Ice mentioning

confidence: 99%

“…Question 4.1 addresses our need to explore and discover the range of diversity of biological ice nuclei in natural environments [2]. Most of the previous reports of biological ice nuclei have focused on culturable microbes (e.g., Pseudomonas syringae and Fusarium avenaceum) (e.g., [91,105]) or ubiquitous components of plant matter, such as pollen grains from common tree species [92] or decaying leaf litter [115]. Understudied are the unculturable microbial ice nucleators, biogenic macromolecules serving as ice nuclei [94,116,117], microorganisms in harsh environments producing ice nuclei, and potential biogenic compounds produced by ice-nucleating plankton [24,95,[118][119][120].…”

Section: Identifying and Quantifying Contributions Of Biological Ice mentioning

confidence: 99%

Perspectives on the Future of Ice Nucleation Research: Research Needs and Unanswered Questions Identified from Two International Workshops

et al. 2017

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There has been increasing interest in ice nucleation research in the last decade. To identify important gaps in our knowledge of ice nucleation processes and their impacts, two international workshops on ice nucleation were held in Vienna, Austria in 2015 and 2016. Experts from these workshops identified the following research needs: (1) uncovering the molecular identity of active sites for ice nucleation; (2) the importance of modeling for the understanding of heterogeneous ice nucleation; (3) identifying and quantifying contributions of biological ice nuclei from natural and managed environments; (4) examining the role of aging in ice nuclei; (5) conducting targeted sampling campaigns in clouds; and (6) designing lab and field experiments to increase our understanding of

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“…Its importance for precipitation on the regional scale has been suggested in a number of studies (Pöschl et al, 2010;Prenni et al, 2013;Huffman et al, 2013;Hader et al, 2014). Birch pollen is one of the most efficient pollen species at nucleating ice as high as 264 K (Diehl et al, 2001(Diehl et al, , 2002von Blohn et al, 2005;Pummer et al, 2012Augustin et al, 2013). Pummer et al (2012) have shown that macromolecules on or within pollen grains are responsible for the ice nucleation activity.…”

Section: Introductionmentioning

confidence: 99%

Refreeze experiments with water droplets containing different types of ice nuclei interpreted by classical nucleation theory

et al. 2017

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Abstract. Homogeneous nucleation of ice in supercooled water droplets is a stochastic process. In its classical description, the growth of the ice phase requires the emergence of a critical embryo from random fluctuations of water molecules between the water bulk and ice-like clusters, which is associated with overcoming an energy barrier. For heterogeneous ice nucleation on ice-nucleating surfaces both stochastic and deterministic descriptions are in use. Deterministic (singular) descriptions are often favored because the temperature dependence of ice nucleation on a substrate usually dominates the stochastic time dependence, and the ease of representation facilitates the incorporation in climate models. Conversely, classical nucleation theory (CNT) describes heterogeneous ice nucleation as a stochastic process with a reduced energy barrier for the formation of a critical embryo in the presence of an ice-nucleating surface. The energy reduction is conveniently parameterized in terms of a contact angle α between the ice phase immersed in liquid water and the heterogeneous surface. This study investigates various ice-nucleating agents in immersion mode by subjecting them to repeated freezing cycles to elucidate and discriminate the time and temperature dependences of heterogeneous ice nucleation. Freezing rates determined from such refreeze experiments are presented for Hoggar Mountain dust, birch pollen washing water, Arizona test dust (ATD), and also nonadecanol coatings. For the analysis of the experimental data with CNT, we assumed the same active site to be always responsible for freezing. Three different CNT-based parameterizations were used to describe rate coefficients for heterogeneous ice nucleation as a function of temperature, all leading to very similar results: for Hoggar Mountain dust, ATD, and larger nonadecanol-coated water droplets, the experimentally determined increase in freezing rate with decreasing temperature is too shallow to be described properly by CNT using the contact angle α as the only fit parameter. Conversely, birch pollen washing water and small nonadecanol-coated water droplets show temperature dependencies of freezing rates steeper than predicted by all three CNT parameterizations. Good agreement of observations and calculations can be obtained when a pre-factor β is introduced to the rate coefficient as a second fit parameter. Thus, the following microphysical picture emerges: heterogeneous freezing occurs at ice-nucleating sites that need a minimum (critical) surface area to host embryos of critical size to grow into a crystal. Fits based on CNT suggest that the critical active site area is in the range of 10-50 nm 2 , with the exact value depending on sample, temperature, and CNT-based parameterization. Two fitting parameters are needed to characterize individual active sites. The contact angle α lowers the energy barrier that has to be overcome to form the critical embryo at the site compared to the homogeneous case where the critical embryo develops in the volume of water....

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The ice nucleating ability of pollen

Cited by 178 publications

References 32 publications

Pollen Rupture and Its Impact on Precipitation in Clean Continental Conditions

Pollen Rupture and Its Impact on Precipitation in Clean Continental Conditions

Perspectives on the Future of Ice Nucleation Research: Research Needs and Unanswered Questions Identified from Two International Workshops

Refreeze experiments with water droplets containing different types of ice nuclei interpreted by classical nucleation theory

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