Tropospheric and stratospheric wildfire smoke profiling with lidar: mass, surface area, CCN, and INP retrieval

Ansmann, Albert; Ohneiser, Kevin; Mamouri, Rodanthi-Elisavet; Knopf, Daniel A.; Veselovskii, Igor; Baars, Holger; Engelmann, Ronny; Foth, Andreas; Jiménez, Cristofer; Seifert, Patric; Barja, Boris

doi:10.5194/acp-21-9779-2021

Cited by 55 publications

(91 citation statements)

References 129 publications

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“…The retrieval of aerosol microphysical properties such as particle volume, mass, and surface area concentration and estimates of cloud-relevant properties such as CCNC and INPC is performed by means of the POLIPHON (Polarization Lidar Photometer Networking) approach Ansmann, 2016, 2017;Marinou et al, 2019;Ansmann et al, 2019Ansmann et al, , 2021. Lidar input data sets are the height profiles of the 532 nm backscatter coefficient and the PLDR.…”

Section: Lidar Productsmentioning

confidence: 99%

“…6a) were on the order of 10 Mm −1 in October, around 4-5 Mm −1 during the main winter months, and mostly ≤ 3 Mm −1 at the end of the lifetime of the smoke layer. From the measured layer mean extinction coefficients, mass concentrations of the smoke particles were derived (Ansmann et al, 2021) and ranged from 0.4-2 µg m −3 during the autumn and winter months. Note that AOT values for a clean stratosphere are around 0.001-0.002 (Sakai et al, 2016;Baars et al, 2019), and minimum extinction coefficients are of the order of 0.1-0.2 Mm −1 .…”

Section: Wildfire Smoke Layer In the Utls Regimementioning

confidence: 99%

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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

et al. 2021

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Abstract. An advanced multiwavelength polarization Raman lidar was operated aboard the icebreaker Polarstern during the MOSAiC (Multidisciplinary drifting Observatory for the Study of Arctic Climate) expedition to continuously monitor aerosol and cloud layers in the central Arctic up to 30 km height. The expedition lasted from September 2019 to October 2020 and measurements were mostly taken between 85 and 88.5∘ N. The lidar was integrated into a complex remote-sensing infrastructure aboard the Polarstern. In this article, novel lidar techniques, innovative concepts to study aerosol–cloud interaction in the Arctic, and unique MOSAiC findings will be presented. The highlight of the lidar measurements was the detection of a 10 km deep wildfire smoke layer over the North Pole region between 7–8 km and 17–18 km height with an aerosol optical thickness (AOT) at 532 nm of around 0.1 (in October–November 2019) and 0.05 from December to March. The dual-wavelength Raman lidar technique allowed us to unambiguously identify smoke as the dominating aerosol type in the aerosol layer in the upper troposphere and lower stratosphere (UTLS). An additional contribution to the 532 nm AOT by volcanic sulfate aerosol (Raikoke eruption) was estimated to always be lower than 15 %. The optical and microphysical properties of the UTLS smoke layer are presented in an accompanying paper (Ohneiser et al., 2021). This smoke event offered the unique opportunity to study the influence of organic aerosol particles (serving as ice-nucleating particles, INPs) on cirrus formation in the upper troposphere. An example of a closure study is presented to explain our concept of investigating aerosol–cloud interaction in this field. The smoke particles were obviously able to control the evolution of the cirrus system and caused low ice crystal number concentration. After the discussion of two typical Arctic haze events, we present a case study of the evolution of a long-lasting mixed-phase cloud layer embedded in Arctic haze in the free troposphere. The recently introduced dual-field-of-view polarization lidar technique was applied, for the first time, to mixed-phase cloud observations in order to determine the microphysical properties of the water droplets. The mixed-phase cloud closure experiment (based on combined lidar and radar observations) indicated that the observed aerosol levels controlled the number concentrations of nucleated droplets and ice crystals.

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Section: Lidar Productsmentioning

confidence: 99%

Section: Wildfire Smoke Layer In the Utls Regimementioning

confidence: 99%

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

et al. 2021

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“…where δ m (= 0.004 for our lidar system) is the molecular depolarization ratio that is related to the specification of the narrowband filters in the receiving unit of the lidar system (Behrendt and Nakamura, 2002). The relative uncertainty for δ p is generally on the order of 5 %-10 % (Mamouri et al, 2013).…”

Section: Polarization Lidarmentioning

confidence: 99%

Retrievals of dust-related particle mass and ice-nucleating particle concentration profiles with ground-based polarization lidar and sun photometer over a megacity in central China

Zhang

Liu

et al. 2021

Atmos. Meas. Tech.

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Abstract. The POLIPHON (polarization lidar photometer networking) method is a powerful pathway to retrieve the height profiles of dust-related particle mass and ice-nucleating particle (INP) concentrations. The conversion factors fitted from the sun photometer observation data are the major part of the POLIPHON computations, which can convert the polarization-lidar-derived dust extinction coefficients into dust-related particle mass and INP concentrations. For the central Chinese megacity of Wuhan (30.5∘ N, 114.4∘ E), located at the downstream area several thousands of kilometers far away from the source regions of Asian dust, dust particles always mix with other aerosols from local emissions. Therefore, very few dust case data sets can be available when using the column-integrated Ångström exponent (for 440–870 nm) <0.3 and aerosol optical depth (at 532 nm) >0.1 recorded by a sun photometer as the filtering criteria. Instead, we present another dust case data set screening scheme that applies the simultaneous polarization lidar observation to verify the occurrence of dust. Based on the 33 dust-intrusion days identified during 2011–2013, the extinction-to-volume (cv,d) and extinction-to-large particle (with radius >250 nm) number concentration (c250,d) conversion factors are determined to be (0.52±0.12)×10-12Mmm3m-3 and 0.19±0.05 Mm cm−3, respectively. The c250,d for Wuhan is 27 % larger than that observed at Lanzhou SACOL (36.0∘ N, 104.1∘ E), a site closer to the Gobi Desert, and tends to be closer to those observed in North Africa and the Middle East, indicating dust aerosols from these two sources are also possibly involved in the dust events observed over Wuhan. As a comparison, the conversion factor c290,c of 0.11±0.02Mmcm-3 for continental aerosol is much smaller than c250,d, indicating that there is no significant influence of urban aerosols on the retrievals of dust-related conversion factor over Wuhan. The conversion factors are applied in a dust event in Wuhan to reveal the typical dust-related immersion-mode INP concentration over East Asian cities. The proposed dust case data set screening scheme may potentially be extended to the other polluted city sites that are more influenced by mixed dust.

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“…Otherwise, the Klett-Fernald method (Fernald, 1984;Klett, 1981) is applied using the elastic signals to retrieve the backscatter coefficients. The relative uncertainties are in the range of 5 %-10 % for backscatter coefficients and depolarization ratios at 355 and 532 nm (Ansmann et al, 1992;Baars et al, 2012). The backscatter coefficient retrieval at 1064 nm may be possible with a relative uncertainty of 15 % using only an elastic signal by assuming a proper lidar ratio.…”

Section: Polly Xt Lidarmentioning

confidence: 99%

“…Adam et al (2020) present a methodology for analyzing the biomass burning events recorded in the EARLINET database and provide a literature review of lidar-derived intensive parameters of biomass burning aerosols (46 reference values from 39 cited papers), including fresh and aged ones. Lidar observations showed that biomass burning aerosols are medium-to highly absorbing particles with an almost spherical shape and small particle size, producing medium to high lidar ratios, low depolarization ratios, and high Ångström exponents (Alados-Arboledas et al, 2011;Amiridis et al, 2009;Baars et al, 2012;Müller et al, 2007;Murayama et al, 2004;Nepomuceno Pereira et al, 2014).…”

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confidence: 99%

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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Tropospheric and stratospheric wildfire smoke profiling with lidar: mass, surface area, CCN, and INP retrieval

Cited by 55 publications

References 129 publications

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

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

Retrievals of dust-related particle mass and ice-nucleating particle concentration profiles with ground-based polarization lidar and sun photometer over a megacity in central China

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

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