The retention of ammonia and sulfur dioxide during riming of ice particles and dendritic snow flakes: laboratory experiments in the Mainz vertical wind tunnel

Blohn, N. von; Diehl, K.; Nölscher, A. C.; Jost, A.; Mitra, Subir K.; Borrmann, Stephan

doi:10.1007/s10874-013-9261-x

Cited by 10 publications

(10 citation statements)

References 31 publications

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“…Other simulations are also conducted for a total of 6, 8, 10, or 12 ammonia molecules in the supercooled water droplets, respectively. All MD simulations demonstrate that the surface air-water layer can accommodate 94-100% ammonia molecules, a feature consistent with several laboratory measurements (31,32). In other words, in realistic atmospheric situations (such as winter stable cloud condition) where the ammonia concentrations are orders of magnitude lower than those used in the MD simulation, the ammonia molecules trapped in the surface air-water layer of the ice particles cannot be easily evaporated under nonconvective conditions.…”

Section: Significancesupporting

confidence: 84%

“…These studies show that the direct measurement of retention efficiency can be affected by other factors in the laboratory and/or ambient environment, including temperature, strength of dissociation, wet/ dry ice cloud growth conditions, riming intensity, concentrations, drop sizes, air speeds, ventilation, etc. (13,31,32,37,38). Indeed, for NH 3 , the retention coefficients reported in the literature fall within wide ranges, such as <0.01 (39), 0.29-1 (31), and 1 (32).…”

Section: Significancementioning

confidence: 89%

“…During the upward movements driven by deep convection, the liquid droplets of clouds are first supercooled and then frozen in the UTLS before they precipitate with atmospheric downdrafts. During this process of liquid-to-ice conversion, some gases in the liquid cloud droplets might be trapped inside the ice particles, but other trace gases might be released into the atmosphere upon freezing; the relative amount of the gas that is retained in this conversion process is characterized by the retention coefficient of that gas (31). Past studies have derived the retention coefficients of different gas species through several laboratory experiments, aircraft measurements, and theoretical calculations but showed controversial results.…”

Section: Significancementioning

confidence: 99%

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A molecular perspective for global modeling of upper atmospheric NH ₃ from freezing clouds

Zhu

Francisco

et al. 2018

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

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Ammonia plays a key role in the neutralization of atmospheric acids such as sulfate and nitrates. A few in situ observations have supported the theory that gas-phase NH concentrations should decrease sharply with altitude and be extremely low in the upper troposphere and lower stratosphere (UTLS). This theory, however, seems inconsistent with recent satellite measurements and is also not supported by the aircraft data showing highly or fully neutralized sulfate aerosol particles by ammonium in the UTLS in many parts of the world. Here we reveal the contributions of deep convective clouds to NH in the UTLS by using integrated cross-scale modeling, which includes molecular dynamic simulations, a global chemistry transport model, and satellite and aircraft measurements. We show that the NH dissolved in liquid cloud droplets is prone to being released into the UTLS upon freezing during deep convection. Because NH emission is not regulated in most countries and its future increase is likely persistent from agricultural growth and the warmer climate, the effect of NH on composition and phase of aerosol particles in the UTLS can be significant, which in turn can affect cirrus cloud formation, radiation, and the budgets of NOx and O.

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Section: Significancesupporting

confidence: 84%

Section: Significancementioning

confidence: 89%

Section: Significancementioning

confidence: 99%

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A molecular perspective for global modeling of upper atmospheric NH ₃ from freezing clouds

Zhu

Francisco

et al. 2018

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

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“…As one hypothesis, NH 3 dissolved in cloud droplets could be released in the upper atmosphere upon freezing during deep convection (C. Ge et al, 2018). In addition to previous laboratory experiments on the retention coefficient of ammonia during riming of ice crystals (von Blohn et al, 2013), the AIDA chamber could be used to determine the retention efficiency of NH 3 in a simulated deep convective cloud system to test the hypothesis above.…”

Section: Discussionmentioning

confidence: 99%

Solid Ammonium Nitrate Aerosols as Efficient Ice Nucleating Particles at Cirrus Temperatures

et al. 2020

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Recent satellite observations and high-altitude aircraft measurements have demonstrated the presence of solid ammonium nitrate particles in the Asian monsoon upper troposphere. Most likely, these particles are formed by a heterogeneous crystallization mechanism, given that efflorescence is strongly inhibited for pure ammonium nitrate solution droplets. Crystallization can be induced by the presence of ammonium sulfate, which more easily crystallizes and serves as a heterogeneous nucleus for the crystallization of ammonium nitrate. In the present study, we have investigated this crystallization pathway for different amounts of ammonium sulfate admixed to ammonium nitrate solution droplets and measured the heterogeneous ice nucleation ability of the crystallized particles at cirrus temperatures in a cloud chamber and with a continuous flow diffusion chamber. We found that an admixture of only 0.6 mol% of ammonium sulfate was sufficient to induce the crystallization of ammonium nitrate at 223 K and 22% RH w . These almost pure, crystalline ammonium nitrate particles showed the same temperature-dependent ice nucleation behavior as observed for other inorganic salts like ammonium sulfate and sodium chloride. At temperatures above 230 K, the crystalline ammonium nitrate particles first deliquesced and nucleated ice homogeneously at ice saturation ratios between about 1.45 and 1.50. Below 230 K, heterogeneous ice nucleation was observed to start at an ice saturation ratio as low as 1.13. The deduced ice nucleation active surface site densities were in the range from 10 10 -10 11 m −2 at ice saturation ratios between 1.2 and 1.4, thus similar in magnitude to those of desert dust particles.

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“…This translated into shorter sampling times while condensing more materiali nto as maller sample volume (1-3 mL). Good retention of nitric acid and ammonia vapors in ice has been demonstrated, previously [14],a nd the potentialf or shorter sampling times was worthwhile. The water impinging method was investigated as an alternative approach in determining the optimal methodf or AN vapor collection and ultimately, quantitation.…”

Section: Collection Efficiencymentioning

confidence: 76%

Volatile Emissions of Ammonium Nitrate under Flowing Conditions

Steinkamp

Giordano

Collins

et al. 2015

Propellants Explo Pyrotec

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1IntroductionThe physical properties of low-volatility military explosives, e.g.,T NT and RDX, have been well characterized,g uiding trace explosives detection efforts worldwide. Due to their simple accessibility and formidable potency,t he explosives comprising improvisede xplosive devices (IEDs) have garnered significant attention in recent years. While the physical properties for some of these explosives, including TATP, are generally well understood, others, such as ammonium nitrate (AN), are not as well characterized.Extensived ata regardingA Na erosols formed in the atmosphere exists as scientists have studied the presence of ammonia and nitric acid in the atmosphere, stemming from multiple anthropogenic sources [1].A tmosphericd ata collected in variousr egions of California [2-5] as well as Japan [6] show thata mmonium nitratea erosol concentrations are in the low to mid mgm À3 range and vary considerably within geographical regions.E ven in regions where relatively low levels are found, it is reasonable to expect, at am inimum, low parts per billion by volume (ppbv) of ammonia and nitric acid as background contamination [4]. Clearly,d etecting an AN-based IED will always be frustrated by the presence of ammonium nitrate aerosols in equilibrium with ammonia and nitric acid vapors.F urthermore, when attempting to generate aq uantitative level of AN vapor in the laboratory,avery careful characterization of the backgroundl evels of ammonia and nitric acid is necessary.

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The retention of ammonia and sulfur dioxide during riming of ice particles and dendritic snow flakes: laboratory experiments in the Mainz vertical wind tunnel

Cited by 10 publications

References 31 publications

A molecular perspective for global modeling of upper atmospheric NH ₃ from freezing clouds

A molecular perspective for global modeling of upper atmospheric NH ₃ from freezing clouds

Solid Ammonium Nitrate Aerosols as Efficient Ice Nucleating Particles at Cirrus Temperatures

Volatile Emissions of Ammonium Nitrate under Flowing Conditions

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The retention of ammonia and sulfur dioxide during riming of ice particles and dendritic snow flakes: laboratory experiments in the Mainz vertical wind tunnel

Cited by 10 publications

References 31 publications

A molecular perspective for global modeling of upper atmospheric NH 3 from freezing clouds

A molecular perspective for global modeling of upper atmospheric NH 3 from freezing clouds

Solid Ammonium Nitrate Aerosols as Efficient Ice Nucleating Particles at Cirrus Temperatures

Volatile Emissions of Ammonium Nitrate under Flowing Conditions

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A molecular perspective for global modeling of upper atmospheric NH ₃ from freezing clouds

A molecular perspective for global modeling of upper atmospheric NH ₃ from freezing clouds