First Results from the German Cal/Val Activities for Aeolus

Baars, Holger; Geiß, Alexander; Wandinger, Ulla; Herzog, A. D.; Engelmann, Ronny; Bühl, Johannes; Radenz, Martin; Seifert, Patric; Ansmann, Albert; Martin, Anne; Leinweber, Ronny; Lehmann, Volker; Weißmann, Martin; Cress, Alexander; Filioglou, Maria; Komppula, Mika; Reitebuch, Oliver

doi:10.1051/epjconf/202023701008

Cited by 15 publications

(16 citation statements)

References 3 publications

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“…As one part of these activities, the regular participation of TROPOS on RV Polarstern (Knust, 2017) cruises within the OCEANET project (Macke et al, 2010;Kanitz et al, 2013;Rittmeister et al, 2017;Bohlmann et al, 2018) offered the unique opportunity to perform ground-based validation above the Atlantic Ocean, a region for which only limited observational data are available. The RV Polarstern cruise PS116 from Bremerhaven, Germany, to Cape Town, Republic of South Africa, took place from 10 November 2018 to 11 December 2018 (Hanfland and König, 2019), shortly after the launch of the satellite.…”

Section: Introductionmentioning

confidence: 99%

Validation of Aeolus wind products above the Atlantic Ocean

et al. 2020

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Abstract. In August 2018, the first Doppler wind lidar in space called Atmospheric Laser Doppler Instrument (ALADIN) was launched on board the satellite Aeolus by the European Space Agency (ESA). Aeolus measures profiles of one horizontal wind component (i.e., mainly the west–east direction) in the troposphere and lower stratosphere on a global basis. Furthermore, profiles of aerosol and cloud properties can be retrieved via the high spectral resolution lidar (HSRL) technique. The Aeolus mission is supposed to improve the quality of weather forecasts and the understanding of atmospheric processes. We used the opportunity to perform a unique validation of the wind products of Aeolus by utilizing the RV Polarstern cruise PS116 from Bremerhaven to Cape Town in November/December 2018. Due to concerted course modifications, six direct intersections with the Aeolus ground track could be achieved in the Atlantic Ocean west of the African continent. For the validation of the Aeolus wind products, we launched additional radiosondes and used the EARLINET/ACTRIS lidar PollyXT for atmospheric scene analysis. The six analyzed cases prove that Aeolus is able to measure horizontal wind speeds in the nearly west–east direction. Good agreements with the radiosonde observations could be achieved for both Aeolus wind products – the winds observed in clean atmospheric regions called Rayleigh winds and the winds obtained in cloud layers called Mie winds (according to the responsible scattering regime). Systematic and statistical errors of the Rayleigh winds were less than 1.5 and 3.3 m s−1, respectively, when compared to radiosonde values averaged to the vertical resolution of Aeolus. For the Mie winds, a systematic and random error of about 1 m s−1 was obtained from the six comparisons in different climate zones. However, it is also shown that the coarse vertical resolution of 2 km in the upper troposphere, which was set in this early mission phase 2 months after launch, led to an underestimation of the maximum wind speed in the jet stream regions. In summary, promising first results of the first wind lidar space mission are shown and prove the concept of Aeolus for global wind observations.

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Section: Introductionmentioning

confidence: 99%

Validation of Aeolus wind products above the Atlantic Ocean

et al. 2020

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“…The stratospheric aerosol perturbation was roughly a factor of 10 higher in terms of extinction and mass concentration over New Zealand on 1 January 2020 than over Punta Arenas as observed with lidar on 9 January 2020, about 8 days later (not shown here) (Ohneiser et al, 2020). The background extinction level of a clean stratosphere is around 0.1 Mm −1 at 532 nm (Sakai et al, 2016;Baars et al, 2019;Taha et al, 2020). Again, INP concentrations were high enough to significantly influence cirrus formation.…”

Section: Fresh Smoke Over Canada and New Zealand Observed With Calipsmentioning

confidence: 49%

“…Such a high aerosol pollution level of 15 µg m −3 at heights from 20-26 km height has never been observed in the stratosphere before, even not after major volcanic eruptions (Trickl et al, 2013;Sakai et al, 2016). Stratospheric background levels are of the order of 0.01 µg m −3 (Baars et al, 2019;Taha et al, 2020).…”

Section: Aged Smoke Over Punta Arenasmentioning

confidence: 89%

“…The POLIPHON method is well validated in a variety of field activities (Mamali al., 2018;Düsing et al, 2018;Marinou et al, 2019;Haarig et al, 2019;Genz et al, 2011) and applied in numerous studies (Cordoba-Jabonero et al, 2018;Georgoulias et al, 2020;Marinou et al, 2019;Ansmann et al, 2019b;Baars et al, 2019;Costa-Surós et al, 2020;Hofer et al, 2020). In the following, we briefly summarize the different parts of the data analysis with special focus on wildfire smoke.…”

Section: Poliphon Method: Smoke Retrievalmentioning

confidence: 99%

“…Record-breaking injections of Canadian and Australian wildfire smoke into the upper troposphere and lower stratosphere (UTLS) in 2017 and 2020 caused strong perturbations of stratospheric aerosol conditions in the northern and southern hemisphere. The smoke reached heights up to 23 km (Canadian smoke, 2017) (Hu et al, 2019;Baars et al, 2019;Torres et al, 2020) and more than 30 km (Australian smoke, 2020) (Ohneiser et al, 2020;Kablick et al, 2020;Khaykin et al, 2020), spread over large parts of the stratosphere, and remained detectable for 6-12 months. Smoke particles influence climate conditions by strong absorption of solar radiation, by acting as cloud condensation nuclei (CCN) and ice nucleating particles (INP) in cloud evolution processes (e.g., cirrus, polar stratospheric clouds), and by facilitating heterogeneous chemical processes due to the aerosol distribution.…”

Section: Introductionmentioning

confidence: 99%

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

Ansmann¹,

Ohneiser²,

Mamouri³

et al. 2020

Preprint

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Abstract. We present retrievals of tropospheric and stratospheric height profiles of particle mass, volume, and surface area concentrations in the case of wildfire smoke layers as well as estimates of smoke-related cloud condensation nucleus (CCN) and ice-nucleating particle (INP) concentrations from single-wavelength backscatter lidar measurements at ground and in space. A central role in the data analysis play conversion factors to convert the measured optical into microphysical properties. The set of needed conversion parameters for wildfire smoke are derived from AERONET observations of major smoke events caused by record-breaking wildfires in western Canada in August 2017 and southeastern Australia in January–February 2020. The new smoke analysis scheme is applied to stratospheric CALIPSO observations of fresh smoke plumes over northern Canada in 2017 and New Zealand in January 2020 and to ground-based lidar observation in southern Chile in aged Australian smoke layers in January 2020. These case studies show the potential of spaceborne and ground-based lidars to document large-scale and long-lasting wildfire smoke events in large detail and thus to provide valuable information for climate-, cloud-, and air chemistry modeling efforts performed to investigate the role of wildfire smoke in the atmospheric system.

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Californian Wildfire Smoke Over Europe: A First Example of the Aerosol Observing Capabilities of Aeolus Compared to Ground‐Based Lidar

Baars

Radenz

Floutsi

et al. 2021

Geophysical Research Letters

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In September 2020, extremely strong wildfires in the western United States of America (i.e., mainly in California) produced large amounts of smoke, which was lifted into the free troposphere. These biomass-burning-aerosol (BBA) layers were transported from the US west coast towards central Europe within 3-4 days turning the sky milky and receiving high media attention. The present study characterises this pronounced smoke plume above Leipzig, Germany, using a ground-based multiwavelength-Raman-polarization lidar and the aerosol/cloud product of ESA's wind lidar mission Aeolus. An exceptional high smoke-AOT > 0.4 was measured, yielding to a mean mass concentration of 8 µg m −3 .The 355 nm lidar ratio was moderate at around 40-50 sr. The Aeolus-derived backscatter, extinction and lidar ratio profiles agree well with the observations of the ground-based lidar PollyXT considering the fact that Aeolus aerosol and cloud products are still preliminary and subject to ongoing algorithm improvements.

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First Results from the German Cal/Val Activities for Aeolus

Cited by 15 publications

References 3 publications

Validation of Aeolus wind products above the Atlantic Ocean

Validation of Aeolus wind products above the Atlantic Ocean

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

Californian Wildfire Smoke Over Europe: A First Example of the Aerosol Observing Capabilities of Aeolus Compared to Ground‐Based Lidar

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