Atmospheric ice nucleators active ≥ −12 °C can be quantified on PM&amp;lt;sub&amp;gt;10&amp;lt;/sub&amp;gt; filters

Conen, Franz; Henne, Stephan; Morris, Cindy E.; Alewell, Christine

doi:10.5194/amt-5-321-2012

Cited by 71 publications

(79 citation statements)

References 37 publications

(33 reference statements)

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“…These INPs are not considered in this study. However, it is interesting to note that the parameterised dust INP concentrations agree well with the Joly et al (2014) data at 260 K. Most of the data from Conen et al (2012) was also taken at temperatures warmer that 260 K, indicating that dust can nucleate ice at temperatures warmer than the Niemand et al (2012) parameterisation. Nevertheless, the concentrations are the same as the parameterisation at 260 K.…”

Section: Discussionsupporting

confidence: 69%

“…These observations were typically for only a few weeks at a time, so climatological time series of ice nuclei are not yet available. Observations presented in several recent studies (Chou et al, 2011;Conen et al, 2012;Joly et al, 2014;Klein et al, 2010) will be used to make a statistical comparison with the results presented here. DeMott et al (2010) provide a best-fit function to a number of observations from outside Europe, which is used here as an additional evaluation tool.…”

Section: Discussionmentioning

confidence: 99%

“…The ice nucleating ability of many aerosols has been experimentally determined through both field (e.g. Cozic et al, 2008;Conen et al, 2012;Joly et al, 2014) and laboratory studies Murray et al, 2012). Mineral dust has been identified as a major contributor to atmospheric ice nucleation at temperatures relevant for mixed phase and cirrus clouds (Heintzenberg et al, 1996;DeMott et al, 2003;Atkinson et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

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Seasonal variability of Saharan desert dust and ice nucleating particles over Europe

et al. 2015

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Abstract. Dust aerosols are thought to be the main contributor to atmospheric ice nucleation. While there are case studies supporting this, a climatological sense of the importance of dust to atmospheric ice nucleating particle (INP) concentrations and its seasonal variability over Europe is lacking. Here, we use a mesoscale model to estimate Saharan dust concentrations over Europe in 2008. There are large differences in median dust concentrations between seasons, with the highest concentrations and highest variability in the lower to mid-troposphere. Laboratory-based ice nucleation parameterisations are applied to these simulated dust number concentrations to calculate the potential INP resulting from immersion freezing and deposition nucleation on these dust particles. The potential INP concentrations increase exponentially with height due to decreasing temperatures in the lower and mid-troposphere. When the ice-activated fraction increases sufficiently, INP concentrations follow the dust particle concentrations. The potential INP profiles exhibit similarly large differences between seasons, with the highest concentrations in spring (median potential immersion INP concentrations nearly 10 5 m −3 , median potential deposition INP concentrations at 120 % relative humidity with respect to ice over 10 5 m −3 ), about an order of magnitude larger than those in summer. Using these results, a best-fit function is provided to estimate the potential INPs for use in limited-area models, which is representative of the normal background INP concentrations over Europe. A statistical evaluation of the results against field and laboratory measurements indicates that the INP concentrations are in close agreement with observations.

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Section: Discussionsupporting

confidence: 69%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Seasonal variability of Saharan desert dust and ice nucleating particles over Europe

et al. 2015

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“…Instruments developed to explore ice nucleation for different formation pathways and to measure the concentration of atmospheric INPs fall into two broad categories: offline measurements of aerosol particles collected on filters (e.g., Bigg, 1967;Klein et al, 2010;Conen et al, 2012) or in suspensions (e.g., Hader et al, 2014), which operate on hourly to daily timescales, and online measurements, which are capable of real-time detection of INP concentration with a higher temporal resolution from seconds to minutes. The portable online instruments report INP concentrations for both groundbased (e.g., DeMott et al, 2010;Chou et al, 2011;Garcia et al, 2012;Tobo et al, 2013) and airborne measurements (Rogers et al, 2001a;DeMott et al, 2003aDeMott et al, , b, 2010.…”

mentioning

confidence: 99%

Leipzig Ice Nucleation chamber Comparison (LINC): intercomparison of four online ice nucleation counters

et al. 2017

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Abstract. Ice crystal formation in atmospheric clouds has a strong effect on precipitation, cloud lifetime, cloud radiative properties, and thus the global energy budget. Primary ice formation above 235 K is initiated by nucleation on seed aerosol particles called ice-nucleating particles (INPs). Instruments that measure the ice-nucleating potential of aerosol particles in the atmosphere need to be able to accurately quantify ambient INP concentrations. In the last decade several instruments have been developed to investigate the icenucleating properties of aerosol particles and to measure ambient INP concentrations. Therefore, there is a need for intercomparisons to ensure instrument differences are not interpreted as scientific findings.In this study, we intercompare the results from parallel measurements using four online ice nucleation chambers. Seven different aerosol types are tested including untreated and acid-treated mineral dusts (microcline, which is a K-feldspar, and kaolinite), as well as birch pollen washing waters. Experiments exploring heterogeneous ice nucleation above and below water saturation are performed to cover the whole range of atmospherically relevant thermodynamic conditions that can be investigated with the intercompared chambers. The Leipzig Aerosol Cloud Interaction Simulator (LACIS) and the Portable Immersion Mode Cooling chAmber coupled to the Portable Ice Nucleation Chamber (PIMCA-PINC) performed measurements in the immersion freezing mode. Additionally, two continuous-flow diffusion chambers (CFDCs) PINC and the Spectrometer for Ice Nuclei (SPIN) are used to perform measurements below and just above water saturation, nominally presenting deposition nucleation and condensation freezing.The results of LACIS and PIMCA-PINC agree well over the whole range of measured frozen fractions (FFs) and temperature. In general PINC and SPIN compare well and the observed differences are explained by the ice crystal growth and different residence times in the chamber. To study the mechanisms responsible for the ice nucleation in the four instruments, the FF (from LACIS and PIMCA-PINC) and the activated fraction, AF (from PINC and SPIN), are compared. Measured FFs are on the order of a factor of 3 higher than AFs, but are not consistent for all aerosol types and temperatures investigated. It is shown that measurements from CFDCs cannot be assumed to produce the same results as those instruments exclusively measuring immersion freezing. Instead, the need to apply a scaling factor to CFDCs operating above water saturation has to be considered to allow comparison with immersion freezing devices. Our results provide further awareness of factors such as the importance of dispersion methods and the quality of particle size selection for intercomparing online INP counters.

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“…Each punch was immersed in Milli-Q water (0.1 mL) in a tube (1.5 mL, Eppendorf Safe-Lock), cooled from −4 to −12 • C (0.3 • C min −1 ) in a cold bath (Lauda, model RC6). The number of frozen tubes were counted every 1 • C temperature step to calculate the number concentration of INPs in sampled air (Conen et al, 2012). The punches from 10 filters in each size fraction were tested a second time after they had been immersed for 10 min in a water bath at 90 • C. We also tested 24 field blanks the same way.…”

Section: Analysis Of Ice-nucleating Particlesmentioning

confidence: 99%

Rainfall drives atmospheric ice-nucleating particles in the coastal climate of southern Norway

et al. 2017

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Atmospheric ice nucleators active ≥ −12 °C can be quantified on PM<sub>10</sub> filters

Cited by 71 publications

References 37 publications

Seasonal variability of Saharan desert dust and ice nucleating particles over Europe

Seasonal variability of Saharan desert dust and ice nucleating particles over Europe

Leipzig Ice Nucleation chamber Comparison (LINC): intercomparison of four online ice nucleation counters

Rainfall drives atmospheric ice-nucleating particles in the coastal climate of southern Norway

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