Integrating laboratory and field data to quantify the immersion freezing ice nucleation activity of mineral dust particles

DeMott, Paul J.; Prenni, A. J.; McMeeking, G. R.; Sullivan, R. C.; Petters, M. D.; Tobo, Yutaka; Niemand, M.; Möhler, Ottmar; Snider, Jefferson R.; Wang, Zhien; Kreidenweis, Sonia M.

doi:10.5194/acp-15-393-2015

Cited by 355 publications

(533 citation statements)

References 51 publications

(72 reference statements)

Supporting

Mentioning

502

Contrasting

Unclassified

Order By: Relevance

“…The use of 105 % RH w in the CFDC has been shown to underestimate INP activity for natural dusts by up to a factor of 3, but is a necessary compromise. Comparably, the CSU-CFDC results agreed well with the AIDA measurements within a factor of 3 in n s ,geo estimation (AIDA n s > CSU-CFDC n s ; DeMott et al, 2015). All the CFDC measurements were conducted with 500 nm mobility diameter size-selected particles, as discussed in the supplementary methods.…”

Section: Csu-cfdcsupporting

confidence: 60%

“…As demonstrated in DeMott et al (2015), higher RH w values were required for full expression of immersion freezing in CSU-CFDC. The use of 105 % RH w in the CFDC has been shown to underestimate INP activity for natural dusts by up to a factor of 3, but is a necessary compromise.…”

Section: Csu-cfdcmentioning

confidence: 99%

“…Likewise, AIDA results indicated slightly higher n s values than CSU-CFDC's results. The lower n s of CSU-CFDC may be a consequence of underestimation of N ice , possibly due to its constrained RH w (at 105 %) and/or the disturbance of aerosol lamina between two plates in a CFDC (DeMott et al, 2015).…”

Section: Imca-zincmentioning

confidence: 99%

See 2 more Smart Citations

A comprehensive laboratory study on the immersion freezing behavior of illite NX particles: a comparison of 17 ice nucleation measurement techniques

et al. 2015

Self Cite

View full text Add to dashboard Cite

Abstract. Immersion freezing is the most relevant heterogeneous ice nucleation mechanism through which ice crystals are formed in mixed-phase clouds. In recent years, an increasing number of laboratory experiments utilizing a variety of instruments have examined immersion freezing activity of atmospherically relevant ice-nucleating particles. However, an intercomparison of these laboratory results is a difficult task because investigators have used different ice nucleation (IN) measurement methods to produce these results. A remaining challenge is to explore the sensitivity and accuracy of these techniques and to understand how the IN results are potentially influenced or biased by experimental parameters associated with these techniques.Within the framework of INUIT (Ice Nuclei Research Unit), we distributed an illite-rich sample (illite NX) as a representative surrogate for atmospheric mineral dust particles to investigators to perform immersion freezing experiments using different IN measurement methods and to obtain Published by Copernicus Publications on behalf of the European Geosciences Union. N. Hiranuma et al.: A comparison of 17 IN measurement techniquesIN data as a function of particle concentration, temperature (T ), cooling rate and nucleation time. A total of 17 measurement methods were involved in the data intercomparison. Experiments with seven instruments started with the test sample pre-suspended in water before cooling, while 10 other instruments employed water vapor condensation onto drydispersed particles followed by immersion freezing. The resulting comprehensive immersion freezing data set was evaluated using the ice nucleation active surface-site density, n s , to develop a representative n s (T ) spectrum that spans a wide temperature range (−37 • C < T < −11 • C) and covers 9 orders of magnitude in n s .In general, the 17 immersion freezing measurement techniques deviate, within a range of about 8 • C in terms of temperature, by 3 orders of magnitude with respect to n s . In addition, we show evidence that the immersion freezing efficiency expressed in n s of illite NX particles is relatively independent of droplet size, particle mass in suspension, particle size and cooling rate during freezing. A strong temperature dependence and weak time and size dependence of the immersion freezing efficiency of illite-rich clay mineral particles enabled the n s parameterization solely as a function of temperature. We also characterized the n s (T ) spectra and identified a section with a steep slope between −20 and −27 • C, where a large fraction of active sites of our test dust may trigger immersion freezing. This slope was followed by a region with a gentler slope at temperatures below −27 • C. While the agreement between different instruments was reasonable below ∼ −27 • C, there seemed to be a different trend in the temperature-dependent ice nucleation activity from the suspension and dry-dispersed particle measurements for this mineral dust, in particular at higher temperatures. For instance,...

show abstract

Section: Csu-cfdcsupporting

confidence: 60%

Section: Csu-cfdcmentioning

confidence: 99%

See 1 more Smart Citation

A comprehensive laboratory study on the immersion freezing behavior of illite NX particles: a comparison of 17 ice nucleation measurement techniques

et al. 2015

Self Cite

View full text Add to dashboard Cite

show abstract

“…heterogenous ice formation is presently in the focus of atmospheric research Murray et al, 2012;Hoose and Möhler, 2012;Atkinson et al, 2013;Phillips et al, 2013;DeMott et al, 2015;Kiselev et al, 2017).…”

mentioning

confidence: 99%

Profiling of Saharan dust from the Caribbean to western Africa – Part 1: Layering structures and optical properties from shipborne polarization/Raman lidar observations

et al. 2017

View full text Add to dashboard Cite

Abstract. We present final and quality-assured results of multiwavelength polarization/Raman lidar observations of the Saharan air layer (SAL) over the tropical Atlantic. Observations were performed aboard the German research vessel R/V Meteor during the 1-month transatlantic cruise from Guadeloupe to Cabo Verde over 4500 km from 61.5 to 20 • W at 14-15 • N in April-May 2013. First results of the shipborne lidar measurements, conducted in the framework of SALTRACE (Saharan Aerosol Long-range Transport and Aerosol-Cloud Interaction Experiment), were reported by Kanitz et al. (2014). Here, we present four observational cases representing key stages of the SAL evolution between Africa and the Caribbean in detail in terms of layering structures and optical properties of the mixture of predominantly dust and aged smoke in the SAL. We discuss to what extent the lidar results confirm the validity of the SAL conceptual model which describes the dust long-range transport and removal processes over the tropical Atlantic. Our observations of a clean marine aerosol layer (MAL, layer from the surface to the SAL base) confirm the conceptual model and suggest that the removal of dust from the MAL, below the SAL, is very efficient. However, the removal of dust from the SAL assumed in the conceptual model to be caused by gravitational settling in combination with large-scale subsidence is weaker than expected. To explain the observed homogenous (heightindependent) dust optical properties from the SAL base to the SAL top, from the African coast to the Caribbean, we have to assume that the particle sedimentation strength is reduced and dust vertical mixing and upward transport mechanisms must be active in the SAL. Based on lidar observations on 20 nights at different longitudes in May 2013, we found, on average, MAL and SAL layer mean values (at 532 nm) of the extinction-to-backscatter ratio (lidar ratio) of 17±5 sr (MAL) and 43 ± 8 sr (SAL), of the particle linear depolarization ratio of 0.025 ± 0.015 (MAL) and 0.19 ± 0.09 (SAL), and of the particle extinction coefficient of 67 ± 45 Mm −1 (MAL) and 68 ± 37 Mm −1 (SAL). The 532 nm optical depth of the lofted SAL was found to be, on average, 0.15 ± 0.13 during the ship cruise. The comparably low values of the SAL mean lidar ratio and depolarization ratio (compared to typical pure dust values of 50-60 sr and 0.3, respectively) in combination with backward trajectories indicate a smoke contribution to light extinction of the order of 20 % during May 2013, at the end of the burning season in central-western Africa.

show abstract

“…The CFDC has been described previously in detail (DeMott et al, 2015;Rogers et al, 2001). Briefly, the CFDC consists of two, vertically mounted concentric copper columns that have been chemically treated to be wettable by liquid water.…”

Section: Continuous Flow Diffusion Chamber 30mentioning

confidence: 99%

Use of the Single Particle Soot Photometer (SP2) as a pre-filter for ice nucleation measurements: Effect of particle mixing state and determination of SP2 conditions to fully vaporize refractory black carbon

Schill¹,

DeMott²,

Levin³

et al. 2017

Preprint

Self Cite

View full text Add to dashboard Cite

Abstract. Ice nucleation is a fundamental atmospheric process that impacts precipitation, cloud lifetimes, and climate. Challenges remain to identify and quantify the compositions and sources of ice nucleating particles (INPs). Assessment of the role of black 10 carbon (BC) as an INP is particularly important due to its anthropogenic sources and abundance at upper tropospheric cloud levels.The role of BC as an INP, however, is unclear. This is, in part, driven by a lack of techniques that directly determine the contribution of refractory BC (rBC) to INP concentrations. One previously developed technique to measure this contribution uses the Single Particle Soot Photometer (SP2) as a pre-filter to an online ice nucleating particle counter. In this technique, rBC particles are selectively heated to their vaporization temperature in the SP2 cavity by a 1064-nm laser. From previous work, however, it is 15 unclear under what SP2 conditions, if any, that the original rBC particles were fully vaporized. Furthermore, previous work also left questions about the effect of the SP2 laser on the ice nucleating properties of several INP proxies and their mixtures with rBC.To answer these questions, we sampled the exhaust of an SP2 with a Scanning Mobility Particle Sizer and a Continuous Flow Diffusion Chamber. Using Aquadag® as an rBC proxy, the effect of several SP2 instrument parameters on the size distribution and physical properties of particles in rBC SP2 exhaust were explored. We found that a high SP2 laser fluence [930 20 nW/(220-nm PSL)] is required to fully vaporize a ~0.76 fg rBC particle. We also found that the exhaust particle size distribution is minimally affected by the SP2 sheath-to-sample ratio; the size of the original rBC particle, however, greatly influences the size distribution of the SP2 exhaust. The effect of the SP2 laser on the ice nucleation efficiency of Snomax®, NX-illite, and Suwannee River Fulvic Acid was studied; these particles acted as proxies for biological, illite-rich mineral dust, and brown carbon INPs, respectively. The original size distribution and ice nucleation efficiency of all non-rBC proxies were unaffected by the SP2 laser. 25 Furthermore, the ice nucleation efficiencies of all proxies were not affected when externally mixed with rBC. These proxies, however, always show a reduction in ice nucleating ability when internally mixed with rBC. We end this work with recommendations for users who wish to use the SP2 as a prefilter to remove large rBC particles from an aerosol stream.

show abstract

Integrating laboratory and field data to quantify the immersion freezing ice nucleation activity of mineral dust particles

Cited by 355 publications

References 51 publications

A comprehensive laboratory study on the immersion freezing behavior of illite NX particles: a comparison of 17 ice nucleation measurement techniques

A comprehensive laboratory study on the immersion freezing behavior of illite NX particles: a comparison of 17 ice nucleation measurement techniques

Profiling of Saharan dust from the Caribbean to western Africa – Part 1: Layering structures and optical properties from shipborne polarization/Raman lidar observations

Use of the Single Particle Soot Photometer (SP2) as a pre-filter for ice nucleation measurements: Effect of particle mixing state and determination of SP2 conditions to fully vaporize refractory black carbon

Contact Info

Product

Resources

About