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1. Atmospheric and Surface Processes, and Feedback Mechanisms Determining Arctic Amplification: A Review of First Results and Prospects of the (AC)3 Project

Author

Wendisch, M., Brückner, M., Crewell, Susanne, Ehrlich, A., Notholt, J., Lüpkes, C., Macke, A., Burrows, J. P., Rinke, A., Quaas, J., Maturilli, M., Schemann, V., Shupe, M. D., Akansu, E. F., Barrientos-Velasco, C., Bärfuss, K., Blechschmidt, A.-M., Block, K., Bougoudis, I., Bozem, H., Böckmann, C., Bracher, A., Bresson, H., Bretschneider, L., Buschmann, M., Chechin, D. G., Chylik, J., Dahlke, S., Deneke, H., Dethloff, K., Donth, T., Dorn, W., Dupuy, R., Ebell, K., Egerer, U., Engelmann, R., Eppers, O., Gerdes, R., Gierens, R., Gorodetskaya, I. V., Gottschalk, M., Griesche, H., Gryanik, V. M., Handorf, D., Harm-Altstädter, B., Hartmann, J., Hartmann, M., Heinold, B., Herber, A., Herrmann, H., Heygster, G., Höschel, I., Hofmann, Z., Hölemann, J., Hünerbein, A., Jafariserajehlou, S., Jäkel, E., Jacobi, C., Janout, M., Jansen, F., Jourdan, O., Jurányi, Z., Kalesse-Los, H., Kanzow, T., Käthner, R., Kliesch, L. L., Klingebiel, M., Knudsen, E. M., Kovács, T., Körtke, W., Krampe, D., Kretzschmar, J., Kreyling, D., Kulla, B., Kunkel, D., Lampert, A., Lauer, M., Lelli, L., von Lerber, A., Linke, O., Löhnert, U., Lonardi, M., Losa, S. N., Losch, M., Maahn, M., Mech, M., Mei, L., Mertes, S., Metzner, E., Mewes, D., Michaelis, J., Mioche, G., Moser, Manuel, Nakoudi, K., Neggers, R., Neuber, R., Nomokonova, T., Oelker, J., Papakonstantinou-Presvelou, I., Pätzold, F., Pefanis, V., Pohl, C., van Pinxteren, M., Radovan, A., Rhein, M., Rex, Markus, Richter, A., Risse, N., Ritter, C., Rostosky, P., Rozanov, V. V., Ruiz Donoso, E., Saavedra-Garfias, P., Salzmann, M., Schacht, J., Schäfer, M., Schneider, J., Schnierstein, N., Seifert, P., Seo, S., Siebert, H., Soppa, M. A., Spreen, G., Stachlewska, I. S., Stapf, J., Stratmann, F., Tegen, I., Viceto, C., Voigt, Christiane, Vountas, M., Walbröl, A., Walter, M., Wehner, B., Wex, H., Willmes, S., Zanatta, M., Zeppenfeld, S., Laboratoire de Météorologie Physique (LaMP), and Institut national des sciences de l'Univers (INSU - CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS)

Subjects
Atmospheric Science, [SDU]Sciences of the Universe [physics], clouds, Arctic amplification
Abstract

Mechanisms behind the phenomenon of Arctic amplification are widely discussed. To contribute to this debate, the (AC)3 project was established in 2016 (www.ac3-tr.de/). It comprises modeling and data analysis efforts as well as observational elements. The project has assembled a wealth of ground-based, airborne, shipborne, and satellite data of physical, chemical, and meteorological properties of the Arctic atmosphere, cryosphere, and upper ocean that are available for the Arctic climate research community. Short-term changes and indications of long-term trends in Arctic climate parameters have been detected using existing and new data. For example, a distinct atmospheric moistening, an increase of regional storm activities, an amplified winter warming in the Svalbard and North Pole regions, and a decrease of sea ice thickness in the Fram Strait and of snow depth on sea ice have been identified. A positive trend of tropospheric bromine monoxide (BrO) column densities during polar spring was verified. Local marine/biogenic sources for cloud condensation nuclei and ice nucleating particles were found. Atmospheric–ocean and radiative transfer models were advanced by applying new parameterizations of surface albedo, cloud droplet activation, convective plumes and related processes over leads, and turbulent transfer coefficients for stable surface layers. Four modes of the surface radiative energy budget were explored and reproduced by simulations. To advance the future synthesis of the results, cross-cutting activities are being developed aiming to answer key questions in four focus areas: lapse rate feedback, surface processes, Arctic mixed-phase clouds, and airmass transport and transformation.

Published
2023

2. Atmospheric and Surface Processes, and Feedback Mechanisms Determining Arctic Amplification: A Review of First Results and Prospects of the (AC)3 Project

Author

Wendisch, M, Brückner, M, Crewell, S, Ehrlich, A, Notholt, J, Lüpkes, C, Macke, A, Burrows, JP, Rinke, A, Quaas, J, Maturilli, M, Schemann, V, Shupe, MD, Akansu, EF, Barrientos-Velasco, C, Bärfuss, K, Blechschmidt, A-M, Block, K, Bougoudis, I, Bozem, H, Böckmann, C, Bracher, A, Bresson, H, Bretschneider, L, Buschmann, M, Chechin, DG, Chylik, J, Dahlke, S, Deneke, H, Dethloff, K, Donth, T, Dorn, W, Dupuy, R, Ebell, K, Egerer, U, Engelmann, R, Eppers, O, Gerdes, R, Gierens, R, Gorodetskaya, IV, Gottschalk, M, Griesche, H, Gryanik, VM, Handorf, D, Harm-Altstädter, B, Hartmann, J, Hartmann, M, Heinold, B, Herber, A, Herrmann, H, Heygster, G, Höschel, I, Hofmann, Z, Hölemann, J, Hünerbein, A, Jafariserajehlou, S, Jäkel, E, Jacobi, C, Janout, M, Jansen, F, Jourdan, O, Jurányi, Z, Kalesse-Los, H, Kanzow, T, Käthner, R, Kliesch, LL, Klingebiel, M, Knudsen, EM, Kovács, T, Körtke, W, Krampe, D, Kretzschmar, J, Kreyling, D, Kulla, B, Kunkel, D, Lampert, A, Lauer, M, Lelli, L, von Lerber, A, Linke, O, Löhnert, U, Lonardi, M, Losa, SN, Losch, M, Maahn, M, Mech, M, Mei, L, Mertes, S, Metzner, E, Mewes, D, Michaelis, J, Mioche, G, Moser, M, Nakoudi, K, Neggers, R, Neuber, R, Nomokonova, T, Oelker, J, Papakonstantinou-Presvelou, I, Pätzold, F, Pefanis, V, Pohl, C, van Pinxteren, M, Radovan, A, Rhein, M, Rex, M, Richter, A, Risse, N, Ritter, C, Rostosky, P, Rozanov, VV, Donoso, E Ruiz, Saavedra Garfias, P, Salzmann, M, Schacht, J, Schäfer, M, Schneider, J, Schnierstein, N, Seifert, P, Seo, S, Siebert, H, Soppa, MA, Spreen, G, Stachlewska, IS, Stapf, J, Stratmann, F, Tegen, I, Viceto, C, Voigt, C, Vountas, M, Walbröl, A, Walter, M, Wehner, B, Wex, H, Willmes, S, Zanatta, M, Zeppenfeld, S, Wendisch, M, Brückner, M, Crewell, S, Ehrlich, A, Notholt, J, Lüpkes, C, Macke, A, Burrows, JP, Rinke, A, Quaas, J, Maturilli, M, Schemann, V, Shupe, MD, Akansu, EF, Barrientos-Velasco, C, Bärfuss, K, Blechschmidt, A-M, Block, K, Bougoudis, I, Bozem, H, Böckmann, C, Bracher, A, Bresson, H, Bretschneider, L, Buschmann, M, Chechin, DG, Chylik, J, Dahlke, S, Deneke, H, Dethloff, K, Donth, T, Dorn, W, Dupuy, R, Ebell, K, Egerer, U, Engelmann, R, Eppers, O, Gerdes, R, Gierens, R, Gorodetskaya, IV, Gottschalk, M, Griesche, H, Gryanik, VM, Handorf, D, Harm-Altstädter, B, Hartmann, J, Hartmann, M, Heinold, B, Herber, A, Herrmann, H, Heygster, G, Höschel, I, Hofmann, Z, Hölemann, J, Hünerbein, A, Jafariserajehlou, S, Jäkel, E, Jacobi, C, Janout, M, Jansen, F, Jourdan, O, Jurányi, Z, Kalesse-Los, H, Kanzow, T, Käthner, R, Kliesch, LL, Klingebiel, M, Knudsen, EM, Kovács, T, Körtke, W, Krampe, D, Kretzschmar, J, Kreyling, D, Kulla, B, Kunkel, D, Lampert, A, Lauer, M, Lelli, L, von Lerber, A, Linke, O, Löhnert, U, Lonardi, M, Losa, SN, Losch, M, Maahn, M, Mech, M, Mei, L, Mertes, S, Metzner, E, Mewes, D, Michaelis, J, Mioche, G, Moser, M, Nakoudi, K, Neggers, R, Neuber, R, Nomokonova, T, Oelker, J, Papakonstantinou-Presvelou, I, Pätzold, F, Pefanis, V, Pohl, C, van Pinxteren, M, Radovan, A, Rhein, M, Rex, M, Richter, A, Risse, N, Ritter, C, Rostosky, P, Rozanov, VV, Donoso, E Ruiz, Saavedra Garfias, P, Salzmann, M, Schacht, J, Schäfer, M, Schneider, J, Schnierstein, N, Seifert, P, Seo, S, Siebert, H, Soppa, MA, Spreen, G, Stachlewska, IS, Stapf, J, Stratmann, F, Tegen, I, Viceto, C, Voigt, C, Vountas, M, Walbröl, A, Walter, M, Wehner, B, Wex, H, Willmes, S, Zanatta, M, and Zeppenfeld, S

Abstract

Mechanisms behind the phenomenon of Arctic amplification are widely discussed. To contribute to this debate, the (AC)3 project was established in 2016 (www.ac3-tr.de/). It comprises modeling and data analysis efforts as well as observational elements. The project has assembled a wealth of ground-based, airborne, shipborne, and satellite data of physical, chemical, and meteorological properties of the Arctic atmosphere, cryosphere, and upper ocean that are available for the Arctic climate research community. Short-term changes and indications of long-term trends in Arctic climate parameters have been detected using existing and new data. For example, a distinct atmospheric moistening, an increase of regional storm activities, an amplified winter warming in the Svalbard and North Pole regions, and a decrease of sea ice thickness in the Fram Strait and of snow depth on sea ice have been identified. A positive trend of tropospheric bromine monoxide (BrO) column densities during polar spring was verified. Local marine/biogenic sources for cloud condensation nuclei and ice nucleating particles were found. Atmospheric–ocean and radiative transfer models were advanced by applying new parameterizations of surface albedo, cloud droplet activation, convective plumes and related processes over leads, and turbulent transfer coefficients for stable surface layers. Four modes of the surface radiative energy budget were explored and reproduced by simulations. To advance the future synthesis of the results, cross-cutting activities are being developed aiming to answer key questions in four focus areas: lapse rate feedback, surface processes, Arctic mixed-phase clouds, and airmass transport and transformation.

Published
2023

3. Temperature dependence of precipitating ice particle number concentrations of Arctic mixed-phase clouds observed by continuous ground-based measurements

Author

Koike, M., Saito, T., Tobo, Y., Ebell, K., Moteki, N., Ohata, S., Mori, T., Yoshida, A., Adachi, K., Baumgardner, D., Ong, C., and Hashino, T.

Abstract

Arctic low level clouds are considered to play a significant role in the Arctic climate system. In this study, we examined a temperature dependence of precipitating ice particle number concentrations of Arctic mixed-phase clouds observed by continuous ground-based in situ measurements. Precipitating particles were measured using an optical disdrometer (MPS, DMT Inc.) at Mt. Zeppelin Observatory in Ny-Alesund (78.9N, 11.9E), Svalbard between years of 2016 and 2020. Based on ground-based cloud radar and lidar observations, we selected a single layer mixed-phase cloud whose cloud-top height was less than 2.5 km. For the ice nucleating particles number concentration (NINP), we adopted typical number concentrations observed at Mt. Zeppelin. Because NINP depends on temperature, we used the value corresponding to the cloud-top temperature. As a result, number concentration fluxes of precipitation particles (Fice) tended to increase with decreasing temperature below approximately -15°C and they agreed with FINP within one order of magnitude. On the other hand, at temperatures above -10°C, Fice was several orders of magnitude higher than FINP. In this paper, we discuss possible reasons for these temperature dependences of Fice., The 28th IUGG General Assembly (IUGG2023) (Berlin 2023)

Published
2023
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4. JOYCE : Jülich Observatory for Cloud Evolution

Author

Löhnert, U., Schween, J. H., Acquistapace, C., Ebell, K., Maahn, M., Barrera-Verdejo, M., Hirsikko, A., Bohn, B., Knaps, A., O’Connor, E., Simmer, C., Wahner, A., and Crewell, S.

Published
2015

5. The Ny-Ålesund Aerosol Cloud Experiment (NASCENT) Overview and First Results

Author

Pasquier, JT, David, RO, Freitas, G, Gierens, R, Gramlich, Y, Haslett, S, Li, G, Schäfer, B, Siegel, K, Wieder, J, Adachi, K, Belosi, F, Carlsen, T, Decesari, S, Ebell, K, Gilardoni, S, Gysel-Beer, M, Henneberger, J, Inoue, J, Kanji, ZA, Koike, M, Kondo, Y, Krejci, R, Lohmann, U, Maturilli, M, Mazzolla, M, Modini, R, Mohr, C, Motos, G, Nenes, A, Nicosia, A, Ohata, S, Paglione, M, Park, S, Pileci, RE, Ramelli, F, Rinaldi, M, Ritter, C, Sato, K, Storelvmo, T, Tobo, Y, Traversi, R, Viola, A, and Zieger, P

Subjects
Atmospheric Science, Atmosphere, Arctic, Cloud microphysics, Cloud radiative effects, Aerosols, Aerosol-cloud interactions, Aerosol-cloud interaction
Abstract

The Arctic is warming at more than twice the rate of the global average. This warming is influenced by clouds, which modulate the solar and terrestrial radiative fluxes and, thus, determine the surface energy budget. However, the interactions among clouds, aerosols, and radiative fluxes in the Arctic are still poorly understood. To address these uncertainties, the Ny-Ålesund Aerosol Cloud Experiment (NASCENT) study was conducted from September 2019 to August 2020 in Ny-Ålesund, Svalbard. The campaign’s primary goal was to elucidate the life cycle of aerosols in the Arctic and to determine how they modulate cloud properties throughout the year. In situ and remote sensing observations were taken on the ground at sea level, at a mountaintop station, and with a tethered balloon system. An overview of the meteorological and the main aerosol seasonality encountered during the NASCENT year is introduced, followed by a presentation of first scientific highlights. In particular, we present new findings on aerosol physicochemical and molecular properties. Further, the role of cloud droplet activation and ice crystal nucleation in the formation and persistence of mixed-phase clouds, and the occurrence of secondary ice processes, are discussed and compared to the representation of cloud processes within the regional Weather Research and Forecasting Model. The paper concludes with research questions that are to be addressed in upcoming NASCENT publications.

Published
2022

6. Overview of the MOSAiC expedition : Atmosphere

Author

Shupe, M. D., Rex, M., Blomquist, B., G. Persson, P. O., Schmale, J., Uttal, T., Althausen, D., Angot, H., Archer, S., Bariteau, L., Beck, I., Bilberry, J., Bucci, S., Buck, C., Boyer, M., Brasseur, Z., Brooks, I. M., Calmer, R., Cassano, J., Castro, V., Chu, D., Costa, D., Cox, C. J., Creamean, J., Crewell, S., Dahlke, S., Damm, E., de Boer, G., Deckelmann, H., Dethloff, K., Dütsch, M., Ebell, K., Ehrlich, A., Ellis, J., Engelmann, R., Fong, A. A., Frey, M. M., Gallagher, M. R., Ganzeveld, L., Gradinger, R., Graeser, J., Greenamyer, V., Griesche, H., Griffiths, S., Hamilton, J., Heinemann, G., Helmig, D., Herber, A., Heuzé, C., Hofer, J., Houchens, T., Howard, D., Inoue, J., Jacobi, H. -W, Jaiser, R., Jokinen, T., Jourdan, O., Jozef, G., King, W., Kirchgaessner, A., Klingebiel, M., Krassovski, M., Krumpen, T., Lampert, A., Landing, W., Laurila, T., Lawrence, D., Lonardi, M., Loose, B., Lüpkes, C., Maahn, M., Macke, A., Maslowski, W., Marsay, C., Maturilli, M., Mech, M., Morris, S., Moser, M., Nicolaus, M., Ortega, P., Osborn, J., Pätzold, F., Perovich, D. K., Petäjä, T., Pilz, C., Pirazzini, R., Posman, K., Powers, H., Pratt, K. A., Preußer, A., Quéléver, L., Radenz, M., Rabe, B., Rinke, A., Sachs, T., Schulz, A., Siebert, H., Silva, T., Solomon, A., Sommerfeld, A., Spreen, G., Stephens, M., Stohl, A., Svensson, Gunilla, Uin, J., Viegas, J., Voigt, C., von der Gathen, P., Wehner, B., Welker, J. M., Wendisch, M., Werner, M., Xie, Z., Yue, F., Shupe, M. D., Rex, M., Blomquist, B., G. Persson, P. O., Schmale, J., Uttal, T., Althausen, D., Angot, H., Archer, S., Bariteau, L., Beck, I., Bilberry, J., Bucci, S., Buck, C., Boyer, M., Brasseur, Z., Brooks, I. M., Calmer, R., Cassano, J., Castro, V., Chu, D., Costa, D., Cox, C. J., Creamean, J., Crewell, S., Dahlke, S., Damm, E., de Boer, G., Deckelmann, H., Dethloff, K., Dütsch, M., Ebell, K., Ehrlich, A., Ellis, J., Engelmann, R., Fong, A. A., Frey, M. M., Gallagher, M. R., Ganzeveld, L., Gradinger, R., Graeser, J., Greenamyer, V., Griesche, H., Griffiths, S., Hamilton, J., Heinemann, G., Helmig, D., Herber, A., Heuzé, C., Hofer, J., Houchens, T., Howard, D., Inoue, J., Jacobi, H. -W, Jaiser, R., Jokinen, T., Jourdan, O., Jozef, G., King, W., Kirchgaessner, A., Klingebiel, M., Krassovski, M., Krumpen, T., Lampert, A., Landing, W., Laurila, T., Lawrence, D., Lonardi, M., Loose, B., Lüpkes, C., Maahn, M., Macke, A., Maslowski, W., Marsay, C., Maturilli, M., Mech, M., Morris, S., Moser, M., Nicolaus, M., Ortega, P., Osborn, J., Pätzold, F., Perovich, D. K., Petäjä, T., Pilz, C., Pirazzini, R., Posman, K., Powers, H., Pratt, K. A., Preußer, A., Quéléver, L., Radenz, M., Rabe, B., Rinke, A., Sachs, T., Schulz, A., Siebert, H., Silva, T., Solomon, A., Sommerfeld, A., Spreen, G., Stephens, M., Stohl, A., Svensson, Gunilla, Uin, J., Viegas, J., Voigt, C., von der Gathen, P., Wehner, B., Welker, J. M., Wendisch, M., Werner, M., Xie, Z., and Yue, F.

Abstract

With the Arctic rapidly changing, the needs to observe, understand, and model the changes are essential. To support these needs, an annual cycle of observations of atmospheric properties, processes, and interactions were made while drifting with the sea ice across the central Arctic during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition from October 2019 to September 2020. An international team designed and implemented the comprehensive program to document and characterize all aspects of the Arctic atmospheric system in unprecedented detail, using a variety of approaches, and across multiple scales. These measurements were coordinated with other observational teams to explore crosscutting and coupled interactions with the Arctic Ocean, sea ice, and ecosystem through a variety of physical and biogeochemical processes. This overview outlines the breadth and complexity of the atmospheric research program, which was organized into 4 subgroups: atmospheric state, clouds and precipitation, gases and aerosols, and energy budgets. Atmospheric variability over the annual cycle revealed important influences from a persistent large-scale winter circulation pattern, leading to some storms with pressure and winds that were outside the interquartile range of past conditions suggested by long-term reanalysis. Similarly, the MOSAiC location was warmer and wetter in summer than the reanalysis climatology, in part due to its close proximity to the sea ice edge. The comprehensiveness of the observational program for characterizing and analyzing atmospheric phenomena is demonstrated via a winter case study examining air mass transitions and a summer case study examining vertical atmospheric evolution. Overall, the MOSAiC atmospheric program successfully met its objectives and was the most comprehensive atmospheric measurement program to date conducted over the Arctic sea ice. The obtained data will support a broad range of coupled-system s

Published
2022
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7. The Ny-Ålesund Aerosol Cloud Experiment (NASCENT) : Overview and First Results

Author

Pasquier, J. T., David, R. O., Freitas, Gabriel, Gierens, R., Gramlich, Yvette, Haslett, Sophie, Li, G., Schäfer, B., Siegel, Karolina, Wieder, J., Adachi, K., Belosi, F., Carlsen, T., Decesari, S., Ebell, K., Gilardoni, S., Gysel-Beer, M., Henneberger, J., Inoue, J., Kanji, Z. A., Koike, M., Kondo, Y., Krejci, Radovan, Lohmann, U., Maturilli, M., Mazzolla, M., Modini, R., Mohr, Claudia, Motos, G., Nenes, A., Nicosia, A., Ohata, S., Paglione, M., Park, S., Pileci, R. E., Ramelli, F., Rinaldi, M., Ritter, C., Sato, K., Storelvmo, T., Tobo, Y., Traversi, R., Viola, A., Zieger, Paul, Pasquier, J. T., David, R. O., Freitas, Gabriel, Gierens, R., Gramlich, Yvette, Haslett, Sophie, Li, G., Schäfer, B., Siegel, Karolina, Wieder, J., Adachi, K., Belosi, F., Carlsen, T., Decesari, S., Ebell, K., Gilardoni, S., Gysel-Beer, M., Henneberger, J., Inoue, J., Kanji, Z. A., Koike, M., Kondo, Y., Krejci, Radovan, Lohmann, U., Maturilli, M., Mazzolla, M., Modini, R., Mohr, Claudia, Motos, G., Nenes, A., Nicosia, A., Ohata, S., Paglione, M., Park, S., Pileci, R. E., Ramelli, F., Rinaldi, M., Ritter, C., Sato, K., Storelvmo, T., Tobo, Y., Traversi, R., Viola, A., and Zieger, Paul

Abstract

The Arctic is warming at more than twice the rate of the global average. This warming is influenced by clouds, which modulate the solar and terrestrial radiative fluxes and, thus, determine the surface energy budget. However, the interactions among clouds, aerosols, and radiative fluxes in the Arctic are still poorly understood. To address these uncertainties, the Ny-Ålesund Aerosol Cloud Experiment (NASCENT) study was conducted from September 2019 to August 2020 in Ny-Ålesund, Svalbard. The campaign’s primary goal was to elucidate the life cycle of aerosols in the Arctic and to determine how they modulate cloud properties throughout the year. In situ and remote sensing observations were taken on the ground at sea level, at a mountaintop station, and with a tethered balloon system. An overview of the meteorological and the main aerosol seasonality encountered during the NASCENT year is introduced, followed by a presentation of first scientific highlights. In particular, we present new findings on aerosol physicochemical and molecular properties. Further, the role of cloud droplet activation and ice crystal nucleation in the formation and persistence of mixed-phase clouds, and the occurrence of secondary ice processes, are discussed and compared to the representation of cloud processes within the regional Weather Research and Forecasting Model. The paper concludes with research questions that are to be addressed in upcoming NASCENT publications.

Published
2022
Full Text
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8. Overview of the MOSAiC expedition:atmosphere

Author

Shupe, M. D. (Matthew D.), Rex, M. (Markus), Blomquist, B. (Byron), Persson, P. O. (P. Ola G.), Schmale, J. (Julia), Uttal, T. (Taneil), Althausen, D. (Dietrich), Angot, H. (Helene), Archer, S. (Stephen), Bariteau, L. (Ludovic), Beck, I. (Ivo), Bilberry, J. (John), Bucci, S. (Silvia), Buck, C. (Clifton), Boyer, M. (Matt), Brasseur, Z. (Zoe), Brooks, I. M. (Ian M.), Calmer, R. (Radiance), Cassano, J. (John), Castro, V. (Vagner), Chu, D. (David), Costa, D. (David), Cox, C. J. (Christopher J.), Creamean, J. (Jessie), Crewell, S. (Susanne), Dahlke, S. (Sandro), Damm, E. (Ellen), de Boer, G. (Gijs), Deckelmann, H. (Holger), Dethloff, K. (Klaus), Duetsch, M. (Marina), Ebell, K. (Kerstin), Ehrlich, A. (Andre), Ellis, J. (Jody), Engelmann, R. (Ronny), Fong, A. A. (Allison A.), Frey, M. M. (Markus M.), Gallagher, M. R. (Michael R.), Ganzeveld, L. (Laurens), Gradinger, R. (Rolf), Graeser, J. (Juergen), Greenamyer, V. (Vernon), Griesche, H. (Hannes), Griffiths, S. (Steele), Hamilton, J. (Jonathan), Heinemann, G. (Guenther), Helmig, D. (Detlev), Herber, A. (Andreas), Heuze, C. (Celine), Hofer, J. (Julian), Houchens, T. (Todd), Howard, D. (Dean), Inoue, J. (Jun), Jacobi, H.-W. (Hans-Werner), Jaiser, R. (Ralf), Jokinen, T. (Tuija), Jourdan, O. (Olivier), Jozef, G. (Gina), King, W. (Wessley), Kirchgaessner, A. (Amelie), Klingebiel, M. (Marcus), Krassovski, M. (Misha), Krumpen, T. (Thomas), Lampert, A. (Astrid), Landing, W. (William), Laurila, T. (Tiia), Lawrence, D. (Dale), Lonardi, M. (Michael), Loose, B. (Brice), Luepkes, C. (Christof), Maahn, M. (Maximilian), Macke, A. (Andreas), Maslowski, W. (Wieslaw), Marsay, C. (Christopher), Maturilli, M. (Marion), Mech, M. (Mario), Morris, S. (Sara), Moser, M. (Manuel), Nicolaus, M. (Marcel), Ortega, P. (Paul), Osborn, J. (Jackson), Paetzold, F. (Falk), Perovich, D. K. (Donald K.), Petäjä, T. (Tuukka), Pilz, C. (Christian), Pirazzini, R. (Roberta), Posman, K. (Kevin), Powers, H. (Heath), Pratt, K. A. (Kerri A.), Preusser, A. (Andreas), Quelever, L. (Lauriane), Radenz, M. (Martin), Rabe, B. (Benjamin), Rinke, A. (Annette), Sachs, T. (Torsten), Schulz, A. (Alexander), Siebert, H. (Holger), Silva, T. (Tercio), Solomon, A. (Amy), Sommerfeld, A. (Anja), Spreen, G. (Gunnar), Stephens, M. (Mark), Stohl, A. (Andreas), Svensson, G. (Gunilla), Uin, J. (Janek), Viegas, J. (Juarez), Voigt, C. (Christiane), von der Gathen, P. (Peter), Wehner, B. (Birgit), Welker, J. M. (Jeffrey M.), Wendisch, M. (Manfred), Werner, M. (Martin), Xie, Z. (ZhouQing), Yue, F. (Fange), Shupe, M. D. (Matthew D.), Rex, M. (Markus), Blomquist, B. (Byron), Persson, P. O. (P. Ola G.), Schmale, J. (Julia), Uttal, T. (Taneil), Althausen, D. (Dietrich), Angot, H. (Helene), Archer, S. (Stephen), Bariteau, L. (Ludovic), Beck, I. (Ivo), Bilberry, J. (John), Bucci, S. (Silvia), Buck, C. (Clifton), Boyer, M. (Matt), Brasseur, Z. (Zoe), Brooks, I. M. (Ian M.), Calmer, R. (Radiance), Cassano, J. (John), Castro, V. (Vagner), Chu, D. (David), Costa, D. (David), Cox, C. J. (Christopher J.), Creamean, J. (Jessie), Crewell, S. (Susanne), Dahlke, S. (Sandro), Damm, E. (Ellen), de Boer, G. (Gijs), Deckelmann, H. (Holger), Dethloff, K. (Klaus), Duetsch, M. (Marina), Ebell, K. (Kerstin), Ehrlich, A. (Andre), Ellis, J. (Jody), Engelmann, R. (Ronny), Fong, A. A. (Allison A.), Frey, M. M. (Markus M.), Gallagher, M. R. (Michael R.), Ganzeveld, L. (Laurens), Gradinger, R. (Rolf), Graeser, J. (Juergen), Greenamyer, V. (Vernon), Griesche, H. (Hannes), Griffiths, S. (Steele), Hamilton, J. (Jonathan), Heinemann, G. (Guenther), Helmig, D. (Detlev), Herber, A. (Andreas), Heuze, C. (Celine), Hofer, J. (Julian), Houchens, T. (Todd), Howard, D. (Dean), Inoue, J. (Jun), Jacobi, H.-W. (Hans-Werner), Jaiser, R. (Ralf), Jokinen, T. (Tuija), Jourdan, O. (Olivier), Jozef, G. (Gina), King, W. (Wessley), Kirchgaessner, A. (Amelie), Klingebiel, M. (Marcus), Krassovski, M. (Misha), Krumpen, T. (Thomas), Lampert, A. (Astrid), Landing, W. (William), Laurila, T. (Tiia), Lawrence, D. (Dale), Lonardi, M. (Michael), Loose, B. (Brice), Luepkes, C. (Christof), Maahn, M. (Maximilian), Macke, A. (Andreas), Maslowski, W. (Wieslaw), Marsay, C. (Christopher), Maturilli, M. (Marion), Mech, M. (Mario), Morris, S. (Sara), Moser, M. (Manuel), Nicolaus, M. (Marcel), Ortega, P. (Paul), Osborn, J. (Jackson), Paetzold, F. (Falk), Perovich, D. K. (Donald K.), Petäjä, T. (Tuukka), Pilz, C. (Christian), Pirazzini, R. (Roberta), Posman, K. (Kevin), Powers, H. (Heath), Pratt, K. A. (Kerri A.), Preusser, A. (Andreas), Quelever, L. (Lauriane), Radenz, M. (Martin), Rabe, B. (Benjamin), Rinke, A. (Annette), Sachs, T. (Torsten), Schulz, A. (Alexander), Siebert, H. (Holger), Silva, T. (Tercio), Solomon, A. (Amy), Sommerfeld, A. (Anja), Spreen, G. (Gunnar), Stephens, M. (Mark), Stohl, A. (Andreas), Svensson, G. (Gunilla), Uin, J. (Janek), Viegas, J. (Juarez), Voigt, C. (Christiane), von der Gathen, P. (Peter), Wehner, B. (Birgit), Welker, J. M. (Jeffrey M.), Wendisch, M. (Manfred), Werner, M. (Martin), Xie, Z. (ZhouQing), and Yue, F. (Fange)

Abstract

With the Arctic rapidly changing, the needs to observe, understand, and model the changes are essential. To support these needs, an annual cycle of observations of atmospheric properties, processes, and interactions were made while drifting with the sea ice across the central Arctic during the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) expedition from October 2019 to September 2020. An international team designed and implemented the comprehensive program to document and characterize all aspects of the Arctic atmospheric system in unprecedented detail, using a variety of approaches, and across multiple scales. These measurements were coordinated with other observational teams to explore crosscutting and coupled interactions with the Arctic Ocean, sea ice, and ecosystem through a variety of physical and biogeochemical processes. This overview outlines the breadth and complexity of the atmospheric research program, which was organized into 4 subgroups: atmospheric state, clouds and precipitation, gases and aerosols, and energy budgets. Atmospheric variability over the annual cycle revealed important influences from a persistent large-scale winter circulation pattern, leading to some storms with pressure and winds that were outside the interquartile range of past conditions suggested by long-term reanalysis. Similarly, the MOSAiC location was warmer and wetter in summer than the reanalysis climatology, in part due to its close proximity to the sea ice edge. The comprehensiveness of the observational program for characterizing and analyzing atmospheric phenomena is demonstrated via a winter case study examining air mass transitions and a summer case study examining vertical atmospheric evolution. Overall, the MOSAiC atmospheric program successfully met its objectives and was the most comprehensive atmospheric measurement program to date conducted over the Arctic sea ice. The obtained data will support a broad range of coupled

Published
2022

10. Plans for a HALO campaign within (AC)3

Author

Wendisch, M., Brückner, Marlen, Crewell, S., Notholt, Justus, Burrows, J. P., Dethloff, Klaus, Ebell, K., Ehrlich, André, Lüpkes, Christof, Macke, Andreas, Quaas, J., Rinke, Annette, Tegen, I., Neggers, Roel, Herber, Andreas, Rex, Markus, Wendisch, M., Brückner, Marlen, Crewell, S., Notholt, Justus, Burrows, J. P., Dethloff, Klaus, Ebell, K., Ehrlich, André, Lüpkes, Christof, Macke, Andreas, Quaas, J., Rinke, Annette, Tegen, I., Neggers, Roel, Herber, Andreas, and Rex, Markus

Published
2017

11. Plans for a HALO campaign within (AC)³

Author

Wendisch, Manfred, Brückner, Marlen, Crewell, S., Notholt, Justus, Burrows, J. P., Dethloff, Klaus, Ebell, K., Ehrlich, André, Lüpkes, Christof, Macke, Andreas, Quaas, J., Rinke, Annette, Tegen, I., Neggers, Roel, Herber, Andreas, Rex, Markus, Wendisch, Manfred, Brückner, Marlen, Crewell, S., Notholt, Justus, Burrows, J. P., Dethloff, Klaus, Ebell, K., Ehrlich, André, Lüpkes, Christof, Macke, Andreas, Quaas, J., Rinke, Annette, Tegen, I., Neggers, Roel, Herber, Andreas, and Rex, Markus

Published
2017

12. Understanding Causes and Effects of Rapid Warming in the Arctic

Author

Wendisch, Manfred, Brückner, Marlen, Burrows, J. P., Crewell, S., Dethloff, Klaus, Ebell, K., Lüpkes, Christof, Macke, Andreas, Notholt, Justus, Quaas, J., Rinke, Annette, Tegen, I., Wendisch, Manfred, Brückner, Marlen, Burrows, J. P., Crewell, S., Dethloff, Klaus, Ebell, K., Lüpkes, Christof, Macke, Andreas, Notholt, Justus, Quaas, J., Rinke, Annette, and Tegen, I.

Published
2017

16. JOYCE Julich Observatory for Cloud Evolution

Author

Loehnert, U., Schween, J. H., Acquistapace, C., Ebell, K., Maahn, M., Barrera-Verdejo, M., Hirsikko, A., Bohn, B., Knaps, A., O'Connor, E., Simmer, C., Wahner, A., Crewell, S., Loehnert, U., Schween, J. H., Acquistapace, C., Ebell, K., Maahn, M., Barrera-Verdejo, M., Hirsikko, A., Bohn, B., Knaps, A., O'Connor, E., Simmer, C., Wahner, A., and Crewell, S.

Abstract

The Julich Observatory for Cloud Evolution (JOYCE), located at Forschungszentrum Julich in the most western part of Germany, is a recently established platform for cloud research. The main objective of JOYCE is to provide observations, which improve our understanding of the cloudy boundary layer in a midlatitude environment. Continuous and temporally highly resolved measurements that are specifically suited to characterize the diurnal cycle of water vapor, stability, and turbulence in the lower troposphere are performed with a special focus on atmosphere-surface interaction. In addition, instruments are set up to measure the micro- and macrophysical properties of clouds in detail and how they interact with different boundary layer processes and the large-scale synoptic situation. For this, JOYCE is equipped with an array of state-of-the-art active and passive remote sensing and in situ instruments, which are briefly described in this scientific overview. As an example, a 24-h time series of the evolution of a typical cumulus cloud-topped boundary layer is analyzed with respect to stability, turbulence, and cloud properties. Additionally, we present longer-term statistics, which can be used to elucidate the diurnal cycle of water vapor, drizzle formation through autoconversion, and warm versus cold rain precipitation formation. Both case studies and long-term observations are important for improving the representation of clouds in climate and numerical weather prediction models.

Published
2015

21. The Ny-angstrom lesund Aerosol Cloud Experiment (NASCENT): Overview and First Results

Author

Pasquier, J. T., David, R. O., Freitas, G., Gierens, R., Gramlich, Y., Haslett, S., Li, G., Schaefer, B., Siegel, K., Wieder, J., Adachi, K., Belosi, F., Carlsen, T., Decesari, S., Ebell, K., Gilardoni, S., Gysel-Beer, M., Henneberger, J., Inoue, J., Kanji, Z. A., Koike, M., Kondo, Y., Krejci, R., Lohmann, U., Maturilli, M., Mazzolla, M., Modini, R., Mohr, C., Motos, G., Nenes, A., Nicosia, A., Ohata, S., Paglione, M., Park, S., Pileci, R. E., Ramelli, F., Rinaldi, M., Ritter, C., Sato, K., Storelvmo, T., Tobo, Y., Traversi, R., Viola, A., and Zieger, P.

Subjects
sea-ice, arctic amplification, microphysical properties, part ii, cloud microphysics, ice-nucleating particles, aerosol-cloud interaction, zeppelin mountain, stratiform clouds, cloud radiative effects, atmosphere, arctic, mixed-phase clouds, environmental-conditions, chemical-composition, aerosols
Abstract

The Arctic is warming at more than twice the rate of the global average. This warming is influenced by clouds, which modulate the solar and terrestrial radiative fluxes and, thus, determine the surface energy budget. However, the interactions among clouds, aerosols, and radiative fluxes in the Arctic are still poorly understood. To address these uncertainties, the Ny-angstrom lesund Aerosol Cloud Experiment (NASCENT) study was conducted from September 2019 to August 2020 in Ny-angstrom lesund, Svalbard. The campaign's primary goal was to elucidate the life cycle of aerosols in the Arctic and to determine how they modulate cloud properties throughout the year. In situ and remote sensing observations were taken on the ground at sea level, at a mountaintop station, and with a tethered balloon system. An overview of the meteorological and the main aerosol seasonality encountered during the NASCENT year is introduced, followed by a presentation of first scientific highlights. In particular, we present new findings on aerosol physicochemical and molecular properties. Further, the role of cloud droplet activation and ice crystal nucleation in the formation and persistence of mixed-phase clouds, and the occurrence of secondary ice processes, are discussed and compared to the representation of cloud processes within the regional Weather Research and Forecasting Model. The paper concludes with research questions that are to be addressed in upcoming NASCENT publications.

23. Atmospheric temperature, water vapour and liquid water path from two microwave radiometers during MOSAiC.

Author

Walbröl A, Crewell S, Engelmann R, Orlandi E, Griesche H, Radenz M, Hofer J, Althausen D, Maturilli M, and Ebell K

Abstract

The microwave radiometers HATPRO (Humidity and Temperature Profiler) and MiRAC-P (Microwave Radiometer for Arctic Clouds - Passive) continuously measured radiation emitted from the atmosphere throughout the Multidisciplinary drifting Observatory for the Study of the Arctic Climate (MOSAiC) expedition on board the research vessel Polarstern. From the measured brightness temperatures, we have retrieved atmospheric variables using statistical methods in a temporal resolution of 1 s covering October 2019 to October 2020. The integrated water vapour (IWV) is derived individually from both radiometers. In addition, we present the liquid water path (LWP), temperature and absolute humidity profiles from HATPRO. To prove the quality and to estimate uncertainty, the data sets are compared to radiosonde measurements from Polarstern. The comparison shows an extremely good agreement for IWV, with standard deviations of 0.08-0.19 kg m -2 (0.39-1.47 kg m -2 ) in dry (moist) situations. The derived profiles of temperature and humidity denote uncertainties of 0.7-1.8 K and 0.6-0.45 gm -3 in 0-2 km altitude., (© 2022. The Author(s).)

Published
2022
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24. Diverting CERT-mediated ceramide transport to mitochondria triggers Bax-dependent apoptosis.

Author

Jain A, Beutel O, Ebell K, Korneev S, and Holthuis JC

Subjects
Biocatalysis, Biological Transport, Endoplasmic Reticulum metabolism, HeLa Cells, Humans, Protein Binding, Protein Transport, Vesicular Transport Proteins metabolism, bcl-2 Homologous Antagonist-Killer Protein metabolism, Apoptosis, Ceramides metabolism, Mitochondria metabolism, Protein Serine-Threonine Kinases metabolism, bcl-2-Associated X Protein metabolism
Abstract

A deregulation of ceramide biosynthesis in the endoplasmic reticulum (ER) is frequently linked to induction of mitochondrial apoptosis. Although in vitro studies suggest that ceramides might initiate cell death by acting directly on mitochondria, their actual contribution to the apoptotic response in living cells is unclear. Here, we have analyzed the consequences of targeting the biosynthetic flow of ceramides to mitochondria using a ceramide transfer protein (encoded by COL4A3BP) equipped with an OMM anchor, mitoCERT. Cells expressing mitoCERT import ceramides into mitochondria and undergo Bax-dependent apoptosis. Apoptosis induction by mitoCERT was abolished through (i) removal of its ceramide transfer domain, (ii) disruption of its interaction with VAMP-associated proteins (VAPs) in the ER, (iii) addition of antagonistic CERT inhibitor HPA12, (iv) blocking de novo ceramide synthesis and (v) targeting of a bacterial ceramidase to mitochondria. Our data provide the first demonstration that translocation of ER ceramides to mitochondria specifically commits cells to death and establish mitoCERT as a valuable new tool to unravel the molecular principles underlying ceramide-mediated apoptosis., (© 2017. Published by The Company of Biologists Ltd.)

Published
2017
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25. Separating mitochondrial protein assembly and endoplasmic reticulum tethering by selective coupling of Mdm10.

Author

Ellenrieder L, Opaliński Ł, Becker L, Krüger V, Mirus O, Straub SP, Ebell K, Flinner N, Stiller SB, Guiard B, Meisinger C, Wiedemann N, Schleiff E, Wagner R, Pfanner N, and Becker T

Subjects
Membrane Proteins chemistry, Mitochondria metabolism, Mitochondrial Membrane Transport Proteins metabolism, Mitochondrial Membranes metabolism, Mitochondrial Proteins chemistry, Models, Biological, Protein Binding, Protein Interaction Domains and Motifs, Protein Structure, Secondary, Saccharomyces cerevisiae Proteins chemistry, Endoplasmic Reticulum metabolism, Membrane Proteins metabolism, Mitochondrial Proteins metabolism, Saccharomyces cerevisiae metabolism, Saccharomyces cerevisiae Proteins metabolism
Abstract

The endoplasmic reticulum-mitochondria encounter structure (ERMES) connects the mitochondrial outer membrane with the ER. Multiple functions have been linked to ERMES, including maintenance of mitochondrial morphology, protein assembly and phospholipid homeostasis. Since the mitochondrial distribution and morphology protein Mdm10 is present in both ERMES and the mitochondrial sorting and assembly machinery (SAM), it is unknown how the ERMES functions are connected on a molecular level. Here we report that conserved surface areas on opposite sides of the Mdm10 β-barrel interact with SAM and ERMES, respectively. We generated point mutants to separate protein assembly (SAM) from morphology and phospholipid homeostasis (ERMES). Our study reveals that the β-barrel channel of Mdm10 serves different functions. Mdm10 promotes the biogenesis of α-helical and β-barrel proteins at SAM and functions as integral membrane anchor of ERMES, demonstrating that SAM-mediated protein assembly is distinct from ER-mitochondria contact sites.

Published
2016
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26. Homogeneous time-resolved G protein-coupled receptor-ligand binding assay based on fluorescence cross-correlation spectroscopy.

Author

Antoine T, Ott D, Ebell K, Hansen K, Henry L, Becker F, and Hannus S

Subjects
Antibodies, Monoclonal chemistry, Binding Sites drug effects, Cells, Cultured, HEK293 Cells, Humans, Kinetics, Ligands, Peptides chemistry, Receptors, G-Protein-Coupled chemistry, Small Molecule Libraries chemistry, Spectrometry, Fluorescence, Time Factors, Antibodies, Monoclonal metabolism, Fluorescent Dyes chemistry, Peptides pharmacology, Receptors, G-Protein-Coupled antagonists & inhibitors, Small Molecule Libraries pharmacology
Abstract

G protein-coupled receptors (GPCRs) mediate many important physiological functions and are considered as one of the most successful therapeutic target classes for a wide spectrum of diseases. Drug discovery projects generally benefit from a broad range of experimental approaches for screening compound libraries and for the characterization of binding modes of drug candidates. Owing to the difficulties in solubilizing and purifying GPCRs, assay formats have been so far mainly limited to cell-based functional assays and radioligand binding assays. In this study, we used fluorescence cross-correlation spectroscopy (FCCS) to analyze the interaction of detergent-solubilized receptors to various types of GPCR ligands: endogenous peptides, small molecules, and a large surrogate antagonist represented by a blocking monoclonal antibody. Our work demonstrates the suitability of the homogeneous and time-resolved FCCS assay format for a robust, high-throughput determination of receptor-ligand binding affinities and kinetic rate constants for various therapeutically relevant GPCRs., (Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.)

Published
2016
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