In-Situ observation of New Particle Formation in the upper troposphere/lower 
stratosphere of the Asian Monsoon Anticyclone

Weigel, Ralf; Mahnke, Christoph; Baumgartner, Manuel; Dragoneas, Antonis; Vogel, Bärbel; Ploeger, Felix; Viciani, Silvia; D’Amato, Francesco; Bucci, Silvia; Legras, Bernard; Luo, B. P.; Borrmann, Stephan

doi:10.5194/acp-2020-1158

Cited by 2 publications

(18 citation statements)

References 97 publications

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“…Due to the detector's signal-to-noise-ratio and counting statistics, the given quantity and durations of too short events bear significant uncertainties. In Weigel et al (2020a). They (ibid.)…”

Section: Terminology and Notationsmentioning

confidence: 99%

“…based on the principle definition used by Weigel et al (2011). Further details concerning the corrections applied to the measured COPAS data, which were obtained throughout StratoClim 2017, are provided by Weigel et al (2020a), where the empirical parameters of 0.8 and 1.2 are introduced.…”

Section: Terminology and Notationsmentioning

confidence: 99%

“…a few hours only, cf. Weigel et al 2020a), an intense NPF event could still be in process when observed, or it had been completed very recently, i.e. 1-2 hours prior to the detection.…”

Section: Terminology and Notationsmentioning

confidence: 99%

“…the grey points in Figure 6a), coincide with the mixing ratios n6 reaching up to several thousands of mg -1 . It is not deducible from COPAS measurements how the enriched particle densities (n6 and coagulation of particles from the ultrafine size range (Weigel et al, 2020a), or whether the particle enrichment is due to larger particles that were entered with the overshooting.…”

Section: Npf In the Iwc-t Parameter Spacementioning

confidence: 99%

“…de Reus et al (2001); Clarke and Kapustin (2002); Weigelt et al (2009); Andreae et al (2018)). The relationship between NPF and ice clouds is discussed in this study, whilst the immediate connection of NPF and deep convective events is addressed in Weigel et al (2020a).…”

Section: Introductionmentioning

confidence: 99%

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New particle formation inside ice clouds: In-situ observations in the tropical tropopause layer of the 2017 Asian Monsoon Anticyclone

Weigel

Mahnke

Baumgartner

et al. 2021

Preprint

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Abstract. From 27 July to 10 August 2017 the airborne StratoClim mission took place in Kathmandu, Nepal where eight mission flights were conducted with the M-55 Geophysica up to altitudes of 20 km. New Particle Formation (NPF) was identified by the abundant presence of ultrafine aerosols, with particle diameters dp smaller than 15 nm, which were in-situ detected by means of condensation nuclei counting techniques. NPF fields in clear-skies as well as in the presence of cloud ice particles (dp > 3 µm) were encountered at upper troposphere/lowermost stratosphere (UT/LS) levels and within the Asian Monsoon Anticyclone (AMA). NPF-generated ultrafine particles in elevated concentrations (Nuf) were frequently found together with cloud ice (in number concentrations Nice of up to 3 cm−3) at heights between ~ 11 km and 16 km. From a total measurement time of ~ 22.5 hours above 10 km altitude, in-cloud NPF was in sum detected over ~ 1.3 hours (~ 50 % of all NPF records throughout StratoClim). Maximum Nuf of up to ~ 11000 cm−3 were detected coincidently with intermediate ice particle concentrations Nice of 0.05–0.1 cm−3 at comparatively moderate carbon monoxide (CO) contents of ~ 90–100 nmol mol−1. Neither under clear-sky nor during in-cloud NPF do the highest Nuf concentrations correlate with the highest CO mixing ratios, suggesting that an elevated pollutant load is not a prerequisite for NPF. Under clear-air conditions, NPF with elevated Nuf (> 8000 cm−3) occurred slightly less often than within clouds. In the presence of cloud ice, NPF with Nuf between 1500–4000 cm−3 were observed about twice as often as under clear air conditions. When ice water contents exceeded 1000 µmol mol−1 in very cold air ( 5000 mg−1) were rarely observed (~ 6 % of in-cloud NPF data). For specifying the constraining mechanisms for NPF possibly imposed by the microphysical properties of the cloud elements, the integral radius (IR) of the ice cloud population was identified as the most practicable indicator. Neither of both, the number of ice particles or the free distance between the ice particles, is clearly related to the NPF-rate detected. The results of a numerical simulation indicates how the IR affects the supersaturation of a condensable vapour, such as sulphuric acid, and that IR determines the effective limitation of NPF rates due to cloud ice.

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Section: Terminology and Notationsmentioning

confidence: 99%

Section: Terminology and Notationsmentioning

confidence: 99%

“…a few hours only, cf. Weigel et al 2020a), an intense NPF event could still be in process when observed, or it had been completed very recently, i.e. 1-2 hours prior to the detection.…”

Section: Terminology and Notationsmentioning

confidence: 99%

Section: Npf In the Iwc-t Parameter Spacementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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New particle formation inside ice clouds: In-situ observations in the tropical tropopause layer of the 2017 Asian Monsoon Anticyclone

Weigel

Mahnke

Baumgartner

et al. 2021

Preprint

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The ATAL within the 2017 Asian Monsoon Anticyclone: Microphysical aerosol properties derived from aircraft-borne in situ measurements

Mahnke¹,

Weigel²,

Cairo³

et al. 2021

Preprint

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Abstract. The Asian summer monsoon is an effective pathway for aerosol particles and precursor substances from the planetary boundary layer over Central, South, and East Asia into the upper troposphere and lower stratosphere. An enhancement of aerosol particles within the Asian monsoon anticyclone (AMA) has been observed by satellites, called the Asian Tropopause Aerosol Layer (ATAL). In this paper we discuss airborne in situ and remote sensing observations of aerosol microphysical properties conducted during the 2017 StratoClim field campaign within the region of the Asian monsoon anticyclone. The aerosol particle measurements aboard the high-altitude research aircraft M55 Geophysica (reached a maximum altitude of about 20.5 km) were conducted by a modified Ultra High Sensitivity Aerosol Spectrometer Airborne (UHSAS-A; particle diameter detection range from 65 nm to 1 µm), the COndensation PArticle counting System (COPAS, for detecting total aerosol densities of submicrometer sized particles), and the Cloud and Aerosol Spectrometer with Detection of POLarization (NIXE-CAS-DPOL). In the COPAS and UHSAS-A vertical particle mixing ratio profiles, the ATAL is evident as a distinct layer between 15 km (≈ 370 K) and 18.5 km altitude (≈ 420 K potential temperature). Within the ATAL, the maximum detected particle mixing ratios (from the median profiles) were 700 mg−1 for diameters between 65 nm to 1 µm (UHSAS-A) and higher than 2500 mg−1 for diameters larger than 10 nm (COPAS). These values are up to two times higher than previously found at similar altitudes in other tropical locations. The difference between the particle mixing ratio profiles measured by the UHSAS-A and the COPAS indicate that the region below the ATAL at potential temperatures from 350 to 370 K is influenced by the fresh nucleation of aerosol particles (diameter

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In-Situ observation of New Particle Formation in the upper troposphere/lower stratosphere of the Asian Monsoon Anticyclone

Cited by 2 publications

References 97 publications

New particle formation inside ice clouds: In-situ observations in the tropical tropopause layer of the 2017 Asian Monsoon Anticyclone

New particle formation inside ice clouds: In-situ observations in the tropical tropopause layer of the 2017 Asian Monsoon Anticyclone

The ATAL within the 2017 Asian Monsoon Anticyclone: Microphysical aerosol properties derived from aircraft-borne in situ measurements

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