Wildfire smoke, Arctic haze, and aerosol effects on mixed-phase and cirrus clouds over the North Pole region during MOSAiC: an introduction

Engelmann, Ronny; Ansmann, Albert; Ohneiser, Kevin; Griesche, Hannes; Radenz, Martin; Hofer, Julian; Althausen, Dietrich; Dahlke, Sandro; Maturilli, Marion; Veselovskii, Igor; Jiménez, Cristofer; Wiesen, Robert; Baars, Holger; Bühl, Johannes; Gebauer, Henriette; Haarig, Moritz; Seifert, Patric; Wandinger, Ulla; Macke, Andreas

doi:10.5194/acp-21-13397-2021

Cited by 48 publications

(71 citation statements)

References 127 publications

(196 reference statements)

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“…During the 1-year MOSAiC expedition the multiwavelength polarization Raman lidar Polly (POrtabLe Lidar sYstem; Engelmann et al, 2016) was continuously operated on board the Polarstern. An overview of the Polarstern lidar instrument and all retrievable aerosol products is given by Engelmann et al (2021). Continuous, automated measurements of aerosol and cloud profiles up to stratospheric heights were collected from 26 September 2019 to 2 October 2020.…”

Section: Mosaic Lidar Data Analysismentioning

confidence: 99%

“…vanced multiwavelength polarization Raman lidar was operated on board the German icebreaker Polarstern (Knust, 2017), which served as the main MOSAiC platform for advanced remote sensing studies of the atmosphere. The ice breaker was trapped in the ice from October 2019 to May 2020 and drifted through the Arctic Ocean at latitudes mainly between 85 and 88.5 • N for 7.5 months, continuously monitoring aerosol and cloud layers in the central Arctic up to 30 km height (Engelmann et al, 2021). MOSAiC was the largest Arctic field campaign ever conducted.…”

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confidence: 99%

“…This smoke-containing layer was present over the North Pole range throughout the winter half-year until the polar vortex, the strongest of the last 40 years (Lawrence et al, 2020), and began to collapse in late April 2020. The occurrence of a persistent aerosol layer with clear wildfire smoke signatures over the entire winter half-year (2019-2020) is one of the outstanding events observed during the MOSAiC expedition (Engelmann et al, 2021). The following question arose: what was the source for this strong UTLS perturbation?…”

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confidence: 99%

“…6. An introduction to our entire MOSAiC measurement programme and our research goals is provided by Engelmann et al (2021).…”

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confidence: 99%

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The unexpected smoke layer in the High Arctic winter stratosphere during MOSAiC 2019–2020

et al. 2021

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Abstract. During the 1-year MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) expedition, the German icebreaker Polarstern drifted through Arctic Ocean ice from October 2019 to May 2020, mainly at latitudes between 85 and 88.5∘ N. A multiwavelength polarization Raman lidar was operated on board the research vessel and continuously monitored aerosol and cloud layers up to a height of 30 km. During our mission, we expected to observe a thin residual volcanic aerosol layer in the stratosphere, originating from the Raikoke volcanic eruption in June 2019, with an aerosol optical thickness (AOT) of 0.005–0.01 at 500 nm over the North Pole area during the winter season. However, the highlight of our measurements was the detection of a persistent, 10 km deep aerosol layer in the upper troposphere and lower stratosphere (UTLS), from about 7–8 to 17–18 km height, with clear and unambiguous wildfire smoke signatures up to 12 km and an order of magnitude higher AOT of around 0.1 in the autumn of 2019. Case studies are presented to explain the specific optical fingerprints of aged wildfire smoke in detail. The pronounced aerosol layer was present throughout the winter half-year until the strong polar vortex began to collapse in late April 2020. We hypothesize that the detected smoke originated from extraordinarily intense and long-lasting wildfires in central and eastern Siberia in July and August 2019 and may have reached the tropopause layer by the self-lifting process. In this article, we summarize the main findings of our 7-month smoke observations and characterize the aerosol in terms of geometrical, optical, and microphysical properties. The UTLS AOT at 532 nm ranged from 0.05–0.12 in October–November 2019 and 0.03–0.06 during the main winter season. The Raikoke aerosol fraction was estimated to always be lower than 15 %. We assume that the volcanic aerosol was above the smoke layer (above 13 km height). As an unambiguous sign of the dominance of smoke in the main aerosol layer from 7–13 km height, the particle extinction-to-backscatter ratio (lidar ratio) at 355 nm was found to be much lower than at 532 nm, with mean values of 55 and 85 sr, respectively. The 355–532 nm Ångström exponent of around 0.65 also clearly indicated the presence of smoke aerosol. For the first time, we show a distinct view of the aerosol layering features in the High Arctic from the surface up to 30 km height during the winter half-year. Finally, we provide a vertically resolved view on the late winter and early spring conditions regarding ozone depletion, smoke occurrence, and polar stratospheric cloud formation. The latter will largely stimulate research on a potential impact of the unexpected stratospheric aerosol perturbation on the record-breaking ozone depletion in the Arctic in spring 2020.

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Section: Mosaic Lidar Data Analysismentioning

confidence: 99%

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confidence: 99%

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confidence: 99%

“…6. An introduction to our entire MOSAiC measurement programme and our research goals is provided by Engelmann et al (2021).…”

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confidence: 99%

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The unexpected smoke layer in the High Arctic winter stratosphere during MOSAiC 2019–2020

et al. 2021

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“…Later on, Baars et al (2019) reported 6 months of observations (from August 2017 to January 2018) of such wildfire smoke aerosols during the episode with a network of 28 EARLINET ground-based lidars in Europe, showing the aerosol properties and the evolution of the smoke layer during the long-range transport. Recently, wildfire smoke layers were measured over the North Pole with a lidar aboard the icebreaker Polarstern during the MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) expedition (Engelmann et al, 2021;Ohneiser et al, 2021). However, the spatial resolution remains sparse, as advanced lidars are expensive.…”

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Mass concentration estimates of long-range-transported Canadian biomass burning aerosols from a multi-wavelength Raman polarization lidar and a ceilometer in Finland

et al. 2021

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Abstract. A quantitative comparison study for Raman lidar and ceilometer observations, and for model simulations of mass concentration estimates of smoke particles is presented. Layers of biomass burning aerosol particles were observed in the lower troposphere, at 2 to 5 km height on 4 to 6 June 2019, over Kuopio, Finland. These long-range-transported smoke particles originated from a Canadian wildfire event. The most pronounced smoke plume detected on 5 June was intensively investigated. Optical properties were retrieved from the multi-wavelength Raman polarization lidar PollyXT. Particle linear depolarization ratios (PDRs) of this plume were measured to be 0.08±0.02 at 355 nm and 0.05±0.01 at 532 nm, suggesting the presence of partly coated soot particles or particles that have mixed with a small amount of dust or other non-spherical aerosol type. The layer-mean PDR at 355 nm (532 nm) decreased during the day from ∼ 0.11 (0.06) in the morning to ∼ 0.05 (0.04) in the evening; this decrease with time could be linked to the particle aging and related changes in the smoke particle shape properties. Lidar ratios were derived as 47±5 sr at 355 nm and 71±5 sr at 532 nm. A complete ceilometer data processing for a Vaisala CL51 ceilometer is presented from a sensor-provided attenuated backscatter coefficient to particle mass concentration (including the water vapor correction for high latitude for the first time). Aerosol backscatter coefficients (BSCs) were measured at four wavelengths (355, 532, 1064 nm from PollyXT and 910 nm from CL51). Two methods, based on a combined lidar and sun-photometer approach, are applied for mass concentration estimations from both PollyXT and the ceilometer CL51 observations. In the first method, no. 1, we used converted BSCs at 532 nm (from measured BSCs) by corresponding measured backscatter-related Ångström exponents, whereas in the second method, no. 2, we used measured BSCs at each wavelength independently. A difference of ∼ 12 % or ∼ 36 % was found between PollyXT and CL51 estimated mass concentrations using method no. 1 or no. 2, showing the potential of mass concentration estimates from a ceilometer. Ceilometer estimations have an uncertainty of ∼ 50 % in the mass retrieval, but the potential of the data lies in the great spatial coverage of these instruments. The mass retrievals were compared with the Modern-Era Retrospective analysis for Research and Applications, version 2 (MERRA-2) meteorological and aerosol reanalysis. The inclusion of dust (as indicated by MERRA-2 data) in the retrieved mass concentration is negligible considering the uncertainties, which also shows that ceilometer observations for mass retrievals can be used even without exact knowledge of the composition of the smoke-dominated aerosol plume in the troposphere.

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Investigating the Presence of Biomass Burning Events at Ny-Ålesund: Optical and Chemical Insights from Summer-Fall 2019

Pulimeno,

Bruschi,

Feltracco

et al. 2024

Atmospheric Environment

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Wildfire smoke, Arctic haze, and aerosol effects on mixed-phase and cirrus clouds over the North Pole region during MOSAiC: an introduction

Cited by 48 publications

References 127 publications

The unexpected smoke layer in the High Arctic winter stratosphere during MOSAiC 2019–2020

The unexpected smoke layer in the High Arctic winter stratosphere during MOSAiC 2019–2020

Mass concentration estimates of long-range-transported Canadian biomass burning aerosols from a multi-wavelength Raman polarization lidar and a ceilometer in Finland

Investigating the Presence of Biomass Burning Events at Ny-Ålesund: Optical and Chemical Insights from Summer-Fall 2019

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