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Book ; Online ; Thesis: Microscopic and spectroscopic analysis of biogenic aerosols

Pöhlker, Christopher

2013

Author's details	Christopher Pöhlker
Language	English
Size	Online-Ressource
Publisher	Universitätsbibliothek Mainz
Publishing place	Mainz
Document type	Book ; Online ; Thesis
Thesis / German Habilitation thesis	Univ., Diss.--Mainz, 2013
Database	Former special subject collection: coastal and deep sea fishing

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Book ; Online ; Thesis: Microscopic and spectroscopic analysis of biogenic aerosols

Pöhlker, Christopher [Verfasser]

2013

Author's details	Christopher Pöhlker
Keywords	Geowissenschaften ; Earth Sciences
Subject code	sg550
Language	English
Publisher	Universitätsbibliothek Mainz
Publishing place	Mainz
Document type	Book ; Online ; Thesis
Database	Digital theses on the web

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Article ; Online: Process-evaluation of forest aerosol-cloud-climate feedback shows clear evidence from observations and large uncertainty in models.

Nature communications

2024 Volume 15, Issue 1, Page(s) 969

Abstract: Natural aerosol feedbacks are expected to become more important in the future, as anthropogenic aerosol emissions decrease due to air quality policy. One such feedback is initiated by the increase in biogenic volatile organic compound (BVOC) emissions ... ...

Abstract	Natural aerosol feedbacks are expected to become more important in the future, as anthropogenic aerosol emissions decrease due to air quality policy. One such feedback is initiated by the increase in biogenic volatile organic compound (BVOC) emissions with higher temperatures, leading to higher secondary organic aerosol (SOA) production and a cooling of the surface via impacts on cloud radiative properties. Motivated by the considerable spread in feedback strength in Earth System Models (ESMs), we here use two long-term observational datasets from boreal and tropical forests, together with satellite data, for a process-based evaluation of the BVOC-aerosol-cloud feedback in four ESMs. The model evaluation shows that the weakest modelled feedback estimates can likely be excluded, but highlights compensating errors making it difficult to draw conclusions of the strongest estimates. Overall, the method of evaluating along process chains shows promise in pin-pointing sources of uncertainty and constraining modelled aerosol feedbacks.
Language	English
Publishing date	2024-02-07
Publishing country	England
Document type	Journal Article
ZDB-ID	2553671-0
ISSN	2041-1723 ; 2041-1723
ISSN (online)	2041-1723
ISSN	2041-1723
DOI	10.1038/s41467-024-45001-y
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Article: Intercomparison of Planetary Boundary Layer Heights Using Remote Sensing Retrievals and ERA5 Reanalysis over Central Amazonia

Dias-Júnior, Cléo Quaresma / Carneiro, Rayonil Gomes / Fisch, Gilberto / D’Oliveira, Flávio Augusto F. / Sörgel, Matthias / Botía, Santiago / Machado, Luiz Augusto T. / Wolff, Stefan / Santos, Rosa Maria N. dos / Pöhlker, Christopher

Remote Sensing. 2022 Sept. 13, v. 14, no. 18

2022

Abstract: The atmospheric boundary layer height (zi) is a key parameter in the vertical transport of mass, energy, moisture, and chemical species between the surface and the free atmosphere. There is a lack of long-term and continuous observations of zi, however, ... ...

Abstract	The atmospheric boundary layer height (zi) is a key parameter in the vertical transport of mass, energy, moisture, and chemical species between the surface and the free atmosphere. There is a lack of long-term and continuous observations of zi, however, particularly for remote regions, such as the Amazon forest. Reanalysis products, such as ERA5, can fill this gap by providing temporally and spatially resolved information on zi. In this work, we evaluate the ERA5 estimates of zi (zi-ERA5) for two locations in the Amazon and corrected them by means of ceilometer, radiosondes, and SODAR measurements (zi-experimental). The experimental data were obtained at the remote Amazon Tall Tower Observatory (ATTO) with its pristine tropical forest cover and the T3 site downwind of the city of Manaus with a mixture of forest (63%), pasture (17%), and rivers (20%). We focus on the rather typical year 2014 and the El Niño year 2015. The comparison of the experimental vs. ERA5 zi data yielded the following results: (i) zi-ERA5 underestimates zi-experimental daytime at the T3 site for both years 2014 (30%, underestimate) and 2015 (15%, underestimate); (ii) zi-ERA5 overestimates zi-experimental daytime at ATTO site (12%, overestimate); (iii) during nighttime, no significant correlation between the zi-experimental and zi-ERA5 was observed. Based on these findings, we propose a correction for the daytime zi-ERA5, for both sites and for both years, which yields a better agreement between experimental and ERA5 data. These results and corrections are relevant for studies at ATTO and the T3 site and can likely also be applied at further locations in the Amazon.
Keywords	El Nino ; chemical species ; energy ; pastures ; sodar ; tropical forests ; troposphere ; Amazonia
Language	English
Dates of publication	2022-0913
Publishing place	Multidisciplinary Digital Publishing Institute
Document type	Article
ZDB-ID	2513863-7
ISSN	2072-4292
ISSN	2072-4292
DOI	10.3390/rs14184561
Database	NAL-Catalogue (AGRICOLA)

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Book ; Online: Vertically resolved aerosol variability at the Amazon Tall Tower Observatory under wet season conditions

Franco, Marco A. / Valiati, Rafael / Holanda, Bruna A. / Meller, Bruno B. / Kremper, Leslie A. / Rizzo, Luciana V. / Carbone, Samara / Morais, Fernando G. / Nascimento, Janaína P. / Andreae, Meinrat O. / Cecchini, Micael A. / Machado, Luiz A. T. / Ponczek, Milena / Pöschl, Ulrich / Walter, David / Pöhlker, Christopher / Artaxo, Paulo

eISSN:

2024

Abstract: The wet season atmosphere in the central Amazon resembles natural conditions with minimal anthropogenic influence, making it one of the rare pre-industrial-like continental areas worldwide. Previous long-term studies have analyzed the properties and ... ...

Abstract	The wet season atmosphere in the central Amazon resembles natural conditions with minimal anthropogenic influence, making it one of the rare pre-industrial-like continental areas worldwide. Previous long-term studies have analyzed the properties and sources of the natural Amazonian background aerosol. However, the vertical profile of the planetary boundary layer (PBL) has not been assessed systematically. Since 2017, such a profile assessment has been possible with the 325 m high tower at the Amazon Tall Tower Observatory (ATTO), located in a largely untouched primary forest in central Amazonia. This study investigates the variability of submicrometer aerosol concentration, size distribution, and optical properties at 60 and 325 m height in the Amazon PBL. The results show significant differences in aerosol volumes and scattering coefficients in the vertical gradient. The aerosol population was well-mixed throughout the boundary layer during the daytime but became separated upon stratification during nighttime. We also found a significant difference in the spectral dependence of the scattering coefficients between the two heights. The analysis of rainfall and related downdrafts revealed changes in the aerosol populations before and after rain events, with absorption and scattering coefficients decreasing as optically active particles are removed by wet deposition. The recovery of absorption and scattering coefficients is faster at 325 m than at 60 m. Convective events were concomitant with rapid increases in the concentration of sub-50 nm particles, likely associated with downdrafts. We found that the aerosol population near the canopy had a significantly higher mass scattering efficiency than at 325 m. It was also observed a clear spectral dependence, with values for λ = 450, 525 and 635 nm of 7.74±0.12, 5.49±0.11and 4.15±0.11 m 2 g −1 , respectively, at 60 m, while at 325 m, the values were 5.26±0.06, 3.76±0.05 and 2.46±0.04 m 2 g −1 , respectively. The equivalent aerosol refractive index results, which were ...
Subject code	333
Language	English
Publishing date	2024-01-09
Publishing country	de
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Book ; Online: The export of African mineral dust across the Atlantic and its impact over the Amazon Basin

Wang, Xurong / Wang, Qiaoqiao / Prass, Maria / Pöhlker, Christopher / Moran-Zuloaga, Daniel / Artaxo, Paulo / Gu, Jianwei / Yang, Ning / Yang, Xiajie / Tao, Jiangchuan / Hong, Juan / Ma, Nan / Cheng, Yafang / Su, Hang / Andreae, Meinrat O.

eISSN: 1680-7324

2023

Abstract: The Amazon Basin is frequently influenced by transatlantic transport of African dust plumes during its wet season (January–April), which not only interrupts the near-pristine atmospheric condition in that season, but also provides nutrient inputs to the ... ...

Abstract	The Amazon Basin is frequently influenced by transatlantic transport of African dust plumes during its wet season (January–April), which not only interrupts the near-pristine atmospheric condition in that season, but also provides nutrient inputs to the Amazon rainforest upon deposition. In this study, we use the chemical transport model GEOS-Chem to investigate the impact of the export of African mineral dust to the Amazon Basin during the period of 2013–2017, constrained by multiple datasets obtained from the AErosol RObotic NETwork (AERONET), MODIS, as well as the Cayenne site and the Amazon Tall Tower Observatory (ATTO) site in the Amazon Basin. With an optimized particle mass size distribution (PMSD) of dust aerosols, the model captures observed aerosol optical depth (AOD) well in terms of both the mean value and the decline rate of the logarithm of AOD over the Atlantic Ocean along the transport path (AOaTP), implying consistency with the observed export efficiency of African dust along the transatlantic transport. With an annual emission of 0.73±0.12 Pg yr −1 , African dust entering the Amazon Basin during the wet season accounts for 40±4.5 % (up to 70 %) of surface aerosol mass concentrations over the basin. Observed dust peaks over the Amazon Basin are generally associated with relatively higher African dust emissions (including the Sahara and the Sahel) and longer lifetimes of dust along the transatlantic transport, i.e., higher export efficiency of African dust across the Atlantic Ocean. The frequency of dust events during the wet season is around 18 % when averaged over the Amazon Basin, with maxima of over 60 % at the northeastern coast. During the dust events, AOD over most of the Amazon Basin is dominated by dust. Based on dust deposition, we further estimate annual inputs of 52±8.7 , 0.97±0.16 , and 21±3.6 mg m −2 yr −1 for iron, phosphorus, and magnesium, respectively, into the Amazon rainforest, which may to some extent compensate for the hydrologic losses of nutrients in the forest ecosystem.
Subject code	333 ; 551
Language	English
Publishing date	2023-09-07
Publishing country	de
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Book ; Online: Dataset

Unfer, Gabriela R. / Machado, Luiz A.T. / Albrecht, Rachel / Cecchini, Micael / Harder, Hartwig / Kremper, Leslie Ann / Magina, Flavio C. / Pöhlker, Mira / Vila-Guerau de Arellano, Jordi / Williams, Earle / Wolff, Stefan / Pöhlker, Christopher

"The Role of the Atmospheric Electric Field and Downdrafts in the Surface Ozone Concentration in the Amazon"

2023

Abstract: The dataset used to generate plots for the manuscript "The Role of the Atmospheric Electric Field and Downdrafts in the Surface Ozone Concentration in the Amazon." It contains data of the electric field, downdrafts, ozone, GLM events, and ultrafine ... ...

Abstract	The dataset used to generate plots for the manuscript "The Role of the Atmospheric Electric Field and Downdrafts in the Surface Ozone Concentration in the Amazon." It contains data of the electric field, downdrafts, ozone, GLM events, and ultrafine particle concentration. All files are in CSV format.
Keywords	downdrafts ; electric field ; lightning ; ozone
Publisher	Leibniz Institute for Tropospheric Research
Publishing country	nl
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article ; Online: Global organic and inorganic aerosol hygroscopicity and its effect on radiative forcing.

Pöhlker, Mira L / Pöhlker, Christopher / Quaas, Johannes / Mülmenstädt, Johannes / Pozzer, Andrea / Andreae, Meinrat O / Artaxo, Paulo / Block, Karoline / Coe, Hugh / Ervens, Barbara / Gallimore, Peter / Gaston, Cassandra J / Gunthe, Sachin S / Henning, Silvia / Herrmann, Hartmut / Krüger, Ovid O / McFiggans, Gordon / Poulain, Laurent / Raj, Subha S /

Reyes-Villegas, Ernesto / Royer, Haley M / Walter, David / Wang, Yuan / Pöschl, Ulrich

Nature communications

2023 Volume 14, Issue 1, Page(s) 6139

Abstract: The climate effects of atmospheric aerosol particles serving as cloud condensation nuclei (CCN) depend on chemical composition and hygroscopicity, which are highly variable on spatial and temporal scales. Here we present global CCN measurements, covering ...

Abstract	The climate effects of atmospheric aerosol particles serving as cloud condensation nuclei (CCN) depend on chemical composition and hygroscopicity, which are highly variable on spatial and temporal scales. Here we present global CCN measurements, covering diverse environments from pristine to highly polluted conditions. We show that the effective aerosol hygroscopicity, κ, can be derived accurately from the fine aerosol mass fractions of organic particulate matter (ϵ
Language	English
Publishing date	2023-10-02
Publishing country	England
Document type	Journal Article
ZDB-ID	2553671-0
ISSN	2041-1723 ; 2041-1723
ISSN (online)	2041-1723
ISSN	2041-1723
DOI	10.1038/s41467-023-41695-8
Database	MEDical Literature Analysis and Retrieval System OnLINE

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Book ; Online: Varying chiral ratio of Pinic acid enantiomers above the Amazon rainforest

Leppla, Denis / Zannoni, Nora / Kremper, Leslie / Williams, Jonathan / Pöhlker, Christopher / Sá, Marta / Solci, Maria Christina / Hoffmann, Thorsten

eISSN: 1680-7324

2021

Abstract: Chiral chemodiversity plays a crucial role in biochemical processes such as insect and plant communication. However, the vast majority of organic aerosol studies do not distinguish between enantiomeric compounds in the particle phase. Here we report ... ...

Abstract	Chiral chemodiversity plays a crucial role in biochemical processes such as insect and plant communication. However, the vast majority of organic aerosol studies do not distinguish between enantiomeric compounds in the particle phase. Here we report chirally specified measurements of secondary organic aerosol (SOA) at the Amazon Tall Tower Observatory (ATTO) at different altitudes during three measurement campaigns at different seasons. Analysis of filter samples by liquid chromatography coupled to mass spectrometry (LC-MS) has shown that the chiral ratio of pinic acid (C 9 H 14 O 4 ) varies with increasing height above the canopy. A similar trend was recently observed for the gas-phase precursor α-pinene, but more pronounced. Nevertheless, the measurements indicate that neither the oxidation of (+/−)-α-pinene nor the incorporation of the products into the particulate phase proceeds with stereo preference and that the chiral information of the precursor molecule is merely transferred to the low-volatility product. The observation of the weaker height gradient of the present enantiomers in the particle phase at the observation site can be explained by the significant differences in the atmospheric lifetimes of reactant and product. Therefore, it is suggested that the chiral ratio of pinic acid is mainly determined by large-scale emission processes of the two precursors, while meteorological, chemical, or physicochemical processes do not play a particular role. Characteristic emissions of the chiral aerosol precursors from different forest ecosystems, in some cases even with contributions from forest related fauna, could thus provide large-scale information on the different contributions to biogenic secondary aerosols via the analytics of the chiral particle-bound degradation products.
Subject code	660 ; 539
Language	English
Publishing date	2021-03-08
Publishing country	de
Document type	Book ; Online
Database	BASE - Bielefeld Academic Search Engine (life sciences selection)

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Article: X-ray Microspectroscopy and Ptychography on Nanoscale Structures in Rock Varnish

Förster, Jan-David / Bykova, Iuliia / Macholdt, Dorothea S. / Jochum, Klaus Peter / Kappl, Michael / Kilcoyne, A. L. David / Müller, Maren / Sorowka, Antje / Weber, Bettina / Weigand, Markus / Schütz, Gisela / Andreae, Meinrat O. / Pöhlker, Christopher

Journal of physical chemistry. 2021 Oct. 06, v. 125, no. 41

2021

Abstract: X-ray microspectroscopy is a powerful analytical method in geoscientific and environmental research as it provides a unique combination of nanoscale imaging with high spectroscopic sensitivity at relatively low beam-related sample damage. In this study, “ ...

Abstract	X-ray microspectroscopy is a powerful analytical method in geoscientific and environmental research as it provides a unique combination of nanoscale imaging with high spectroscopic sensitivity at relatively low beam-related sample damage. In this study, “classical” scanning transmission soft X-ray microscopy (STXM) with X-ray absorption spectroscopy and the recently established soft X-ray ptychography are applied to the analysis of selected rock varnish samples from urban and arid desert environments. X-ray ptychography enhances the spatial resolution relative to STXM by up to 1 order of magnitude. With its high chemical sensitivity, it can resolve nanoscale differences in valence states of the key varnish elements manganese (Mn) and iron. Our results emphasize the complex nanoarchitecture of rock varnish as well as the diverse mineralogy of the Mn oxy–hydroxide matrix and its embedded dust grains. In contrast to the fast-growing urban varnish, the slow-growing arid desert varnish revealed a remarkable nanoscale stratification of alternating Mn valence states, providing hints on the layer-wise and still enigmatic growth process.
Keywords	X-radiation ; X-ray absorption spectroscopy ; dust ; iron ; manganese ; microscopy ; mineralogy ; physical chemistry
Language	English
Dates of publication	2021-1006
Size	p. 22684-22697.
Publishing place	American Chemical Society
Document type	Article
ISSN	1932-7455
DOI	10.1021/acs.jpcc.1c03600
Database	NAL-Catalogue (AGRICOLA)

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