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157 results on '"Siebesma, A. Pier"'

1. Clouds dissipate quickly during solar eclipses as the land surface cools

Author

Trees, Victor J. H., de Roode, Stephan R., Wiltink, Job I., Meirink, Jan Fokke, Wang, Ping, Stammes, Piet, and Siebesma, A. Pier

Subjects
Physics - Atmospheric and Oceanic Physics, Astrophysics - Earth and Planetary Astrophysics, Astrophysics - Solar and Stellar Astrophysics, Physics - Geophysics
Abstract

Clouds affected by solar eclipses could influence the reflection of sunlight back into space and might change local precipitation patterns. Satellite cloud retrievals have so far not taken into account the lunar shadow, hindering a reliable spaceborne assessment of the eclipse-induced cloud evolution. Here we use satellite cloud measurements during three solar eclipses between 2005 and 2016 that have been corrected for the partial lunar shadow together with large-eddy simulations to analyze the eclipse-induced cloud evolution. Our corrected data reveal that, over cooling land surfaces, shallow cumulus clouds start to disappear at very small solar obscurations. Our simulations explain that the cloud response was delayed and was initiated at even smaller solar obscurations. We demonstrate that neglecting the disappearance of clouds during a solar eclipse could lead to a considerable overestimation of the eclipse-related reduction of net incoming solar radiation. These findings should spur cloud model simulations of the direct consequences of sunlight-intercepting geoengineering proposals, for which our results serve as a unique benchmark.

Published
2024
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2. Shallow Cumulus Cloud Fields Are Optically Thicker When They Are More Clustered

Author

Alinaghi, Pouriya, Janssens, Martin, Choudhury, Goutam, Goren, Tom, Siebesma, A. Pier, and Glassmeier, Franziska

Subjects
Physics - Atmospheric and Oceanic Physics
Abstract

Shallow trade cumuli over subtropical oceans are a persistent source of uncertainty in climate projections. Mesoscale organization of trade cumulus clouds has been shown to influence their cloud radiative effect (CRE) through cloud cover. We investigate whether organization can explain CRE variability independently of cloud cover variability. By analyzing satellite observations and high-resolution simulations, we show that increased clustering leads to geometrically thicker clouds with larger domain-averaged liquid water paths, smaller cloud droplets, and consequently, larger cloud optical depths. The relationships between these variables are shaped by the mixture of deep cloud cores and shallower interstitial clouds or anvils that characterize cloud organization. Eliminating cloud cover effects, more clustered clouds reflect up to 20 W/m$^2$ more instantaneous shortwave radiation back to space.

Published
2023

3. Non-precipitating shallow cumulus convection is intrinsically unstable to length-scale growth

Author

Janssens, Martin, de Arellano, Jordi Vilà-Guerau, van Heerwaarden, Chiel C., de Roode, Stephan R., Siebesma, A. Pier, and Glassmeier, Franziska

Subjects
Physics - Atmospheric and Oceanic Physics
Abstract

Condensation in cumulus clouds plays a key role in structuring the mean, non-precipitating trade-wind boundary layer. Here, we summarise how this role also explains the spontaneous growth of mesoscale ($>O(10)$ km) fluctuations in clouds and moisture around the mean state in a minimal-physics, large-eddy simulation of the undisturbed period during BOMEX on a large ($O(100)$ km) domain. Small, spatial anomalies in latent heating in cumulus clouds, which form on top of small moisture fluctuations, give rise to circulations that transport moisture, but not heat, from dry to moist regions, and thus reinforce the latent heating anomaly. We frame this positive feedback as a linear instability in mesoscale moisture fluctuations, whose time-scale depends only on i) a vertical velocity scale and ii) the mean environment's vertical structure. In our minimal-physics setting, we show both ingredients are provided by the shallow cumulus convection itself: It is intrinsically unstable to length scale growth. The upshot is that energy released by clouds at kilometre scales may play a more profound and direct role in shaping the mesoscale trade-wind environment than is generally appreciated, motivating further research into the mechanism's relevance.

Published
2022
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6. Open boundary conditions for atmospheric large-eddy simulations and their implementation in DALES4.4.

Author

Liqui Lung, Franciscus, Jakob, Christian, Siebesma, A. Pier, and Jansson, Fredrik

Subjects
WEATHER, TURBULENCE, LARGE eddy simulation models, EDDIES
Abstract

Open boundary conditions were developed for atmospheric large-eddy simulation (LES) models and implemented into the Dutch Atmospheric Large-Eddy Simulation model. The implementation was tested in a "Big Brother"-like setup, in which the simulation with open boundary conditions was forced by an identical control simulation with periodic boundary conditions. The results show that the open boundary implementation has minimal influence on the solution. Both the mean state and the turbulent structures are close to the control simulation, and disturbances at the in- and outflow boundaries are negligible. To emulate a setup in which the LES is coupled to a coarser model, the influence of coarse boundary input was tested by smoothing the output of the periodic control simulation both temporally and spatially before feeding it as input to the simulation with open boundary conditions. When smoothing is applied over larger spatial and longer temporal scales, disturbances start to form at the inflow boundary and an area exists where turbulence needs to develop. Adding synthetic turbulence to the smoothed input reduces the size of this area and the magnitude of the disturbances. [ABSTRACT FROM AUTHOR]

Published
2024
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7. Cancellation of cloud shadow effects in the absorbing aerosol index retrieval algorithm of TROPOMI.

Author

Trees, Victor J. H., Wang, Ping, Stammes, Piet, Tilstra, Lieuwe G., Donovan, David P., and Siebesma, A. Pier

Subjects
BIG data, AEROSOLS, ALGORITHMS, ALBEDO, RADIATIVE transfer, AIR quality, PHASE-shifting interferometry
Abstract

Cloud shadows can be detected in the radiance measurements of the TROPOMI instrument on board the Sentinel-5P satellite due to its high spatial resolution, and could possibly affect its air quality products. The cloud shadow induced signatures are, however, not always apparent and may depend on various cloud and scene parameters. Hence, the quantification of the cloud shadow impact requires the analysis of large data sets. Here we use the cloud shadow detection algorithm DARCLOS to detect cloud shadow pixels in the TROPOMI absorbing aerosol index (AAI) product over Europe during 8 months. For every shadow pixel, we automatically select cloud- and shadow-free neighbour pixels, in order to estimate the cloud shadow induced signature. In addition, we simulate the measured cloud shadow impact on the AAI with our newly developed 3D radiative transfer algorithm MONKI. Both the measurements and simulations show that the average cloud shadow impact on the AAI is close to zero (0.06 and 0.16, respectively). However, the top-of-atmosphere reflectance ratio between 340 and 380 nm, which is used to compute the AAI, is significantly increased in 95 % of the shadow pixels. So, cloud shadows are bluer than surrounding non-shadow pixels. Our simulations explain that the traditional AAI formula intrinsically already corrects for this cloud shadow effect, via the lower retrieved scene albedo. This cancellation of cloud shadow signatures is not always perfect, sometimes yielding second order low and high biases in the AAI which we also successfully reproduce with our simulations. We show that the magnitude of those second order cloud shadow effects depends on various cloud parameters which are difficult to determine for the shadows measured with TROPOMI. We conclude that a potential cloud shadow correction strategy for the TROPOMI AAI would therefore be complicated if not unnecessary. [ABSTRACT FROM AUTHOR]

Published
2024
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12. EUREC 4 A

Author

Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Stevens, Bjorn, Bony, Sandrine, Farrell, David, Ament, Felix, Blyth, Alan, Fairall, Christopher, Karstensen, Johannes, Quinn, Patricia K., Speich, Sabrina, Acquistapace, Claudia, Aemisegger, Franziska, Albright, Anna Lea, Bellenger, Hugo, Bodenschatz, Eberhard, Caesar, Kathy-Ann, Chewitt-Lucas, Rebecca, de Boer, Gijs, Delanoë, Julien, Denby, Leif, Ewald, Florian, Fildier, Benjamin, Forde, Marvin, George, Geet, Gross, Silke, Hagen, Martin, Hausold, Andrea, Heywood, Karen J., Hirsch, Lutz, Jacob, Marek, Jansen, Friedhelm, Kinne, Stefan, Klocke, Daniel, Kölling, Tobias, Konow, Heike, Lothon, Marie, Mohr, Wiebke, Naumann, Ann Kristin, Nuijens, Louise, Olivier, Léa, Pincus, Robert, Pöhlker, Mira, Reverdin, Gilles, Roberts, Gregory, Schnitt, Sabrina, Schulz, Hauke, Siebesma, A. Pier, Stephan, Claudia Christine, Sullivan, Peter, Touzé-Peiffer, Ludovic, Vial, Jessica, Vogel, Raphaela, Zuidema, Paquita, Alexander, Nicola, Alves, Lyndon, Arixi, Sophian, Asmath, Hamish, Bagheri, Gholamhossein, Baier, Katharina, Bailey, Adriana, Baranowski, Dariusz, Baron, Alexandre, Barrau, Sébastien, Barrett, Paul A., Batier, Frédéric, Behrendt, Andreas, Bendinger, Arne, Beucher, Florent, Bigorre, Sebastien, Blades, Edmund, Blossey, Peter, Bock, Olivier, Böing, Steven, Bosser, Pierre, Bourras, Denis, Bouruet-Aubertot, Pascale, Bower, Keith, Branellec, Pierre, Branger, Hubert, Brennek, Michal, Brewer, Alan, Brilouet, Pierre-Etienne, Brügmann, Björn, Buehler, Stefan A., Burke, Elmo, Burton, Ralph, Calmer, Radiance, Canonici, Jean-Christophe, Carton, Xavier, Cato Jr., Gregory, Charles, Jude Andre, Chazette, Patrick, Chen, Yanxu, Chilinski, Michal T., Choularton, Thomas, Chuang, Patrick, Clarke, Shamal, Coe, Hugh, Cornet, Céline, Coutris, Pierre, Couvreux, Fleur, Crewell, Susanne, Cronin, Timothy, Cui, Zhiqiang, Cuypers, Yannis, Daley, Alton, Damerell, Gillian M., Dauhut, Thibaut, Deneke, Hartwig, Desbios, Jean-Philippe, Dörner, Steffen, Donner, Sebastian, Douet, Vincent, Drushka, Kyla, Dütsch, Marina, Ehrlich, André, Emanuel, Kerry, Emmanouilidis, Alexandros, Etienne, Jean-Claude, Etienne-Leblanc, Sheryl, Faure, Ghislain, Feingold, Graham, Ferrero, Luca, Fix, Andreas, Flamant, Cyrille, Flatau, Piotr Jacek, Foltz, Gregory R., Forster, Linda, Furtuna, Iulian, Gadian, Alan, Galewsky, Joseph, Gallagher, Martin, Gallimore, Peter, Gaston, Cassandra, Gentemann, Chelle, Geyskens, Nicolas, Giez, Andreas, Gollop, John, Gouirand, Isabelle, Gourbeyre, Christophe, de Graaf, Dörte, de Groot, Geiske E., Grosz, Robert, Güttler, Johannes, Gutleben, Manuel, Hall, Kashawn, Harris, George, Helfer, Kevin C., Henze, Dean, Herbert, Calvert, Holanda, Bruna, Ibanez-Landeta, Antonio, Intrieri, Janet, Iyer, Suneil, Julien, Fabrice, Kalesse, Heike, Kazil, Jan, Kellman, Alexander, Kidane, Abiel T., Kirchner, Ulrike, Klingebiel, Marcus, Körner, Mareike, Kremper, Leslie Ann, Kretzschmar, Jan, Krüger, Ovid, Kumala, Wojciech, Kurz, Armin, L'Hégaret, Pierre, Labaste, Matthieu, Lachlan-Cope, Tom, Laing, Arlene, Landschützer, Peter, Lang, Theresa, Lange, Diego, Lange, Ingo, Laplace, Clément, Lavik, Gauke, Laxenaire, Rémi, Le Bihan, Caroline, Leandro, Mason, Lefevre, Nathalie, Lena, Marius, Lenschow, Donald, Li, Qiang, Lloyd, Gary, Los, Sebastian, Losi, Niccolò, Lovell, Oscar, Luneau, Christopher, Makuch, Przemyslaw, Malinowski, Szymon, Manta, Gaston, Marinou, Eleni, Marsden, Nicholas, Masson, Sebastien, Maury, Nicolas, Mayer, Bernhard, Mayers-Als, Margarette, Mazel, Christophe, McGeary, Wayne, McWilliams, James C., Mech, Mario, Mehlmann, Melina, Meroni, Agostino Niyonkuru, Mieslinger, Theresa, Minikin, Andreas, Minnett, Peter, Möller, Gregor, Morfa Avalos, Yanmichel, Muller, Caroline, Musat, Ionela, Napoli, Anna, Neuberger, Almuth, Noisel, Christophe, Noone, David, Nordsiek, Freja, Nowak, Jakub L., Oswald, Lothar, Parker, Douglas J., Peck, Carolyn, Person, Renaud, Philippi, Miriam, Plueddemann, Albert, Pöhlker, Christopher, Pörtge, Veronika, Pöschl, Ulrich, Pologne, Lawrence, Posyniak, Michał, Prange, Marc, Quiñones Meléndez, Estefanía, Radtke, Jule, Ramage, Karim, Reimann, Jens, Renault, Lionel, Reus, Klaus, Reyes, Ashford, Ribbe, Joachim, Ringel, Maximilian, Ritschel, Markus, Rocha, Cesar B., Rochetin, Nicolas, Röttenbacher, Johannes, Rollo, Callum, Royer, Haley, Sadoulet, Pauline, Saffin, Leo, Sandiford, Sanola, Sandu, Irina, Schäfer, Michael, Schemann, Vera, Schirmacher, Imke, Schlenczek, Oliver, Schmidt, Jerome, Schröder, Marcel, Schwarzenboeck, Alfons, Sealy, Andrea, Senff, Christoph J., Serikov, Ilya, Shohan, Samkeyat, Siddle, Elizabeth, Smirnov, Alexander, Späth, Florian, Spooner, Branden, Stolla, M. Katharina, Szkółka, Wojciech, de Szoeke, Simon P., Tarot, Stéphane, Tetoni, Eleni, Thompson, Elizabeth, Thomson, Jim, Tomassini, Lorenzo, Totems, Julien, Ubele, Alma Anna, Villiger, Leonie, von Arx, Jan, Wagner, Thomas, Walther, Andi, Webber, Ben, Wendisch, Manfred, Whitehall, Shanice, Wiltshire, Anton, Wing, Allison A., Wirth, Martin, Wiskandt, Jonathan, Wolf, Kevin, Worbes, Ludwig, Wright, Ethan, Wulfmeyer, Volker, Young, Shanea, Zhang, Chidong, Zhang, Dongxiao, Ziemen, Florian, Zinner, Tobias, Zöger, Martin, Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences, Stevens, Bjorn, Bony, Sandrine, Farrell, David, Ament, Felix, Blyth, Alan, Fairall, Christopher, Karstensen, Johannes, Quinn, Patricia K., Speich, Sabrina, Acquistapace, Claudia, Aemisegger, Franziska, Albright, Anna Lea, Bellenger, Hugo, Bodenschatz, Eberhard, Caesar, Kathy-Ann, Chewitt-Lucas, Rebecca, de Boer, Gijs, Delanoë, Julien, Denby, Leif, Ewald, Florian, Fildier, Benjamin, Forde, Marvin, George, Geet, Gross, Silke, Hagen, Martin, Hausold, Andrea, Heywood, Karen J., Hirsch, Lutz, Jacob, Marek, Jansen, Friedhelm, Kinne, Stefan, Klocke, Daniel, Kölling, Tobias, Konow, Heike, Lothon, Marie, Mohr, Wiebke, Naumann, Ann Kristin, Nuijens, Louise, Olivier, Léa, Pincus, Robert, Pöhlker, Mira, Reverdin, Gilles, Roberts, Gregory, Schnitt, Sabrina, Schulz, Hauke, Siebesma, A. Pier, Stephan, Claudia Christine, Sullivan, Peter, Touzé-Peiffer, Ludovic, Vial, Jessica, Vogel, Raphaela, Zuidema, Paquita, Alexander, Nicola, Alves, Lyndon, Arixi, Sophian, Asmath, Hamish, Bagheri, Gholamhossein, Baier, Katharina, Bailey, Adriana, Baranowski, Dariusz, Baron, Alexandre, Barrau, Sébastien, Barrett, Paul A., Batier, Frédéric, Behrendt, Andreas, Bendinger, Arne, Beucher, Florent, Bigorre, Sebastien, Blades, Edmund, Blossey, Peter, Bock, Olivier, Böing, Steven, Bosser, Pierre, Bourras, Denis, Bouruet-Aubertot, Pascale, Bower, Keith, Branellec, Pierre, Branger, Hubert, Brennek, Michal, Brewer, Alan, Brilouet, Pierre-Etienne, Brügmann, Björn, Buehler, Stefan A., Burke, Elmo, Burton, Ralph, Calmer, Radiance, Canonici, Jean-Christophe, Carton, Xavier, Cato Jr., Gregory, Charles, Jude Andre, Chazette, Patrick, Chen, Yanxu, Chilinski, Michal T., Choularton, Thomas, Chuang, Patrick, Clarke, Shamal, Coe, Hugh, Cornet, Céline, Coutris, Pierre, Couvreux, Fleur, Crewell, Susanne, Cronin, Timothy, Cui, Zhiqiang, Cuypers, Yannis, Daley, Alton, Damerell, Gillian M., Dauhut, Thibaut, Deneke, Hartwig, Desbios, Jean-Philippe, Dörner, Steffen, Donner, Sebastian, Douet, Vincent, Drushka, Kyla, Dütsch, Marina, Ehrlich, André, Emanuel, Kerry, Emmanouilidis, Alexandros, Etienne, Jean-Claude, Etienne-Leblanc, Sheryl, Faure, Ghislain, Feingold, Graham, Ferrero, Luca, Fix, Andreas, Flamant, Cyrille, Flatau, Piotr Jacek, Foltz, Gregory R., Forster, Linda, Furtuna, Iulian, Gadian, Alan, Galewsky, Joseph, Gallagher, Martin, Gallimore, Peter, Gaston, Cassandra, Gentemann, Chelle, Geyskens, Nicolas, Giez, Andreas, Gollop, John, Gouirand, Isabelle, Gourbeyre, Christophe, de Graaf, Dörte, de Groot, Geiske E., Grosz, Robert, Güttler, Johannes, Gutleben, Manuel, Hall, Kashawn, Harris, George, Helfer, Kevin C., Henze, Dean, Herbert, Calvert, Holanda, Bruna, Ibanez-Landeta, Antonio, Intrieri, Janet, Iyer, Suneil, Julien, Fabrice, Kalesse, Heike, Kazil, Jan, Kellman, Alexander, Kidane, Abiel T., Kirchner, Ulrike, Klingebiel, Marcus, Körner, Mareike, Kremper, Leslie Ann, Kretzschmar, Jan, Krüger, Ovid, Kumala, Wojciech, Kurz, Armin, L'Hégaret, Pierre, Labaste, Matthieu, Lachlan-Cope, Tom, Laing, Arlene, Landschützer, Peter, Lang, Theresa, Lange, Diego, Lange, Ingo, Laplace, Clément, Lavik, Gauke, Laxenaire, Rémi, Le Bihan, Caroline, Leandro, Mason, Lefevre, Nathalie, Lena, Marius, Lenschow, Donald, Li, Qiang, Lloyd, Gary, Los, Sebastian, Losi, Niccolò, Lovell, Oscar, Luneau, Christopher, Makuch, Przemyslaw, Malinowski, Szymon, Manta, Gaston, Marinou, Eleni, Marsden, Nicholas, Masson, Sebastien, Maury, Nicolas, Mayer, Bernhard, Mayers-Als, Margarette, Mazel, Christophe, McGeary, Wayne, McWilliams, James C., Mech, Mario, Mehlmann, Melina, Meroni, Agostino Niyonkuru, Mieslinger, Theresa, Minikin, Andreas, Minnett, Peter, Möller, Gregor, Morfa Avalos, Yanmichel, Muller, Caroline, Musat, Ionela, Napoli, Anna, Neuberger, Almuth, Noisel, Christophe, Noone, David, Nordsiek, Freja, Nowak, Jakub L., Oswald, Lothar, Parker, Douglas J., Peck, Carolyn, Person, Renaud, Philippi, Miriam, Plueddemann, Albert, Pöhlker, Christopher, Pörtge, Veronika, Pöschl, Ulrich, Pologne, Lawrence, Posyniak, Michał, Prange, Marc, Quiñones Meléndez, Estefanía, Radtke, Jule, Ramage, Karim, Reimann, Jens, Renault, Lionel, Reus, Klaus, Reyes, Ashford, Ribbe, Joachim, Ringel, Maximilian, Ritschel, Markus, Rocha, Cesar B., Rochetin, Nicolas, Röttenbacher, Johannes, Rollo, Callum, Royer, Haley, Sadoulet, Pauline, Saffin, Leo, Sandiford, Sanola, Sandu, Irina, Schäfer, Michael, Schemann, Vera, Schirmacher, Imke, Schlenczek, Oliver, Schmidt, Jerome, Schröder, Marcel, Schwarzenboeck, Alfons, Sealy, Andrea, Senff, Christoph J., Serikov, Ilya, Shohan, Samkeyat, Siddle, Elizabeth, Smirnov, Alexander, Späth, Florian, Spooner, Branden, Stolla, M. Katharina, Szkółka, Wojciech, de Szoeke, Simon P., Tarot, Stéphane, Tetoni, Eleni, Thompson, Elizabeth, Thomson, Jim, Tomassini, Lorenzo, Totems, Julien, Ubele, Alma Anna, Villiger, Leonie, von Arx, Jan, Wagner, Thomas, Walther, Andi, Webber, Ben, Wendisch, Manfred, Whitehall, Shanice, Wiltshire, Anton, Wing, Allison A., Wirth, Martin, Wiskandt, Jonathan, Wolf, Kevin, Worbes, Ludwig, Wright, Ethan, Wulfmeyer, Volker, Young, Shanea, Zhang, Chidong, Zhang, Dongxiao, Ziemen, Florian, Zinner, Tobias, and Zöger, Martin

Abstract

Abstract. The science guiding the EUREC4A campaign and its measurements is presented. EUREC4A comprised roughly 5 weeks of measurements in the downstream winter trades of the North Atlantic – eastward and southeastward of Barbados. Through its ability to characterize processes operating across a wide range of scales, EUREC4A marked a turning point in our ability to observationally study factors influencing clouds in the trades, how they will respond to warming, and their link to other components of the earth system, such as upper-ocean processes or the life cycle of particulate matter. This characterization was made possible by thousands (2500) of sondes distributed to measure circulations on meso- (200 km) and larger (500 km) scales, roughly 400 h of flight time by four heavily instrumented research aircraft; four global-class research vessels; an advanced ground-based cloud observatory; scores of autonomous observing platforms operating in the upper ocean (nearly 10 000 profiles), lower atmosphere (continuous profiling), and along the air–sea interface; a network of water stable isotopologue measurements; targeted tasking of satellite remote sensing; and modeling with a new generation of weather and climate models. In addition to providing an outline of the novel measurements and their composition into a unified and coordinated campaign, the six distinct scientific facets that EUREC4A explored – from North Brazil Current rings to turbulence-induced clustering of cloud droplets and its influence on warm-rain formation – are presented along with an overview of EUREC4A's outreach activities, environmental impact, and guidelines for scientific practice. Track data for all platforms are standardized and accessible at https://doi.org/10.25326/165 (Stevens, 2021), and a film documenting the campaign is provided as a video supplement.

Published
2023

13. Open Boundary Conditions for Atmospheric Large Eddy Simulations and the Implementation in DALES4.4.

Author

Liqui Lung, Franciscus, Jakob, Christian, Siebesma, A. Pier, and Jansson, Fredrik

Subjects
WEATHER, TURBULENCE
Abstract

Open boundary conditions were developed for atmospheric large eddy simulation (LES) models and implemented into the Dutch Atmospheric Large Eddy simulation model. The implementation was tested in a "Big Brother"-like setup, in which the simulation with open boundary conditions was forced by an identical control simulation with periodic boundary conditions. The results show that the open boundary implementation has minimal influence on the solution. Both the mean 5 state and the turbulent structures are close to the control simulation and disturbances at the in- and outflow boundaries are negligible. To emulate a setup in which the LES is coupled to a coarser model, the influence of coarse boundary input was tested by smoothing the output of the periodic control simulation both temporally and spatially before feeding it as input to the simulation with open boundary conditions. The results show that when the ratio between input and model resolution increases, disturbances start to form at the inflow boundary and an area exists where turbulence needs to develop. Adding synthetic 10 turbulence to the smoothed input reduces the size of this area and the magnitude of the disturbances. [ABSTRACT FROM AUTHOR]

Published
2023
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15. Turbulent Transport in the Gray Zone: A Large Eddy Model Intercomparison Study of the CONSTRAIN Cold Air Outbreak Case

Author

Roode, Stephan R. de, Frederikse, Thomas, Siebesma, A. Pier, Ackerman, Andrew S, Chylik, Jan, Field, Paul R, Fricke, Jens, Gryschka, Micha, Hill, Adrian, Honnert, Rachel, Krueger, Steve K, Lac, Christine, Lesage, Andrew T, and Tomassini, Lorenzo

Subjects
Meteorology And Climatology
Abstract

To quantify the turbulent transport at gray zone length scales between 1 and 10 km the Lagrangian evolution of the CONSTRAIN cold air outbreak (CAO) case was simulated with seven large eddy models. The case is characterized by rather large latent and sensible heat fluxes, and a rapid deepening rate of the boundary layer. In some models the entrainment velocity exceeds 4 cm/s. A significant fraction of this growth is attributed to a strong longwave radiative cooling of the inversion layer. The evolution and the timing of the breakup of the stratocumulus cloud deck differ significantly among the models. Sensitivity experiments demonstrate that a decrease in the prescribed cloud droplet number concentration, and the inclusion of ice microphysics, both act to speed up the thinning of the stratocumulus by enhancing the production of precipitation. In all models the formation of mesoscale fluctuations is clearly evident in the cloud fields but also in the horizontal wind velocity. Resolved vertical fluxes remain important for scales up to 10 km. The simulation results show that the resolved vertical velocity variance gradually diminishes with a coarsening of the horizontal mesh, but the total vertical fluxes of heat, moisture, and momentum are only weakly affected. This is a promising result as it demonstrates the potential use of a mesh size dependent turbulent length scale for convective boundary layers at gray zone model resolutions.

Published
2019
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20. Representing cloud mesoscale variability in superparameterized climate models

Author

Jansson, F.R. (Fredrik), Oord, G. (Gijs) van den, Pelupessy, F.I. (Inti), Chertova, M. (Maria), Grönqvist, J.H. (Johanna), Siebesma, A.P. (Pier), Crommelin, D.T. (Daan), Jansson, F.R. (Fredrik), Oord, G. (Gijs) van den, Pelupessy, F.I. (Inti), Chertova, M. (Maria), Grönqvist, J.H. (Johanna), Siebesma, A.P. (Pier), and Crommelin, D.T. (Daan)

Abstract

In atmospheric modeling, superparameterization (SP) has gained popularity as a technique to improve cloud and convection representations in large-scale models by coupling them locally to cloud-resolving models. We show how the different representations of cloud water in the local and the global models in SP lead to a suppression of cloud advection and ultimately to a systematic underrepresentation of the cloud amount in the large-scale model. We demonstrate this phenomenon in a regional SP experiment with the global model OpenIFS coupled to the local model Dutch Atmospheric Large Eddy Simulation, as well as in an idealized setup, where the large-scale model is replaced by a simple advection scheme. As a starting point for mitigating the problem of suppressed cloud advection, we propose a scheme where the spatial variability of the local model's total water content is enhanced in order to match the global model's cloud condensate amount. The proposed scheme enhances the cloud condensate amount in the test cases, however a large discrepancy remains, caused by rapid dissipation of the clouds added by the proposed scheme.

Published
2022
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21. DALES - Dutch Atmospheric Large Eddy Simulation

Author

Arabas, S. (Sylwester), Axelsen, S. (Simon), Attema, J. (Jisk), Beets, C., Boeing, S.J., Bruine, M. (Marco) de, Chylik, J. (Jan), Cuijpers, H. (Hans), Dussen, J. (Johan) van der, Heerwaarden, C.C. (Chiel) van, Heus, T. (Thijs), Jansson, F.R. (Fredrik), Jonker, H.J.J. (Harm), Moene, A. (Arnold), Ouwersloot, H. (Huug), Oord, G. (Gijs) van den, Roode, S.R. (Stephan) de, Neggers, R. (Roel), Pedruzo, X. (Xabier), Siebesma, A.P. (Pier), Sikma, M. (Martin), Stratum, B. (Bart) van, Vila, J. (Jordi), Zanten, M. (Margreet) van, Arabas, S. (Sylwester), Axelsen, S. (Simon), Attema, J. (Jisk), Beets, C., Boeing, S.J., Bruine, M. (Marco) de, Chylik, J. (Jan), Cuijpers, H. (Hans), Dussen, J. (Johan) van der, Heerwaarden, C.C. (Chiel) van, Heus, T. (Thijs), Jansson, F.R. (Fredrik), Jonker, H.J.J. (Harm), Moene, A. (Arnold), Ouwersloot, H. (Huug), Oord, G. (Gijs) van den, Roode, S.R. (Stephan) de, Neggers, R. (Roel), Pedruzo, X. (Xabier), Siebesma, A.P. (Pier), Sikma, M. (Martin), Stratum, B. (Bart) van, Vila, J. (Jordi), and Zanten, M. (Margreet) van

Abstract

The version of DALES used on Fugaku for the Cloud Botany dataset.

Published
2022

26. EUREC<sup>4</sup>A

Author

Stevens, Bjorn, primary, Bony, Sandrine, additional, Farrell, David, additional, Ament, Felix, additional, Blyth, Alan, additional, Fairall, Christopher, additional, Karstensen, Johannes, additional, Quinn, Patricia K., additional, Speich, Sabrina, additional, Acquistapace, Claudia, additional, Aemisegger, Franziska, additional, Albright, Anna Lea, additional, Bellenger, Hugo, additional, Bodenschatz, Eberhard, additional, Caesar, Kathy-Ann, additional, Chewitt-Lucas, Rebecca, additional, de Boer, Gijs, additional, Delanoë, Julien, additional, Denby, Leif, additional, Ewald, Florian, additional, Fildier, Benjamin, additional, Forde, Marvin, additional, George, Geet, additional, Gross, Silke, additional, Hagen, Martin, additional, Hausold, Andrea, additional, Heywood, Karen J., additional, Hirsch, Lutz, additional, Jacob, Marek, additional, Jansen, Friedhelm, additional, Kinne, Stefan, additional, Klocke, Daniel, additional, Kölling, Tobias, additional, Konow, Heike, additional, Lothon, Marie, additional, Mohr, Wiebke, additional, Naumann, Ann Kristin, additional, Nuijens, Louise, additional, Olivier, Léa, additional, Pincus, Robert, additional, Pöhlker, Mira, additional, Reverdin, Gilles, additional, Roberts, Gregory, additional, Schnitt, Sabrina, additional, Schulz, Hauke, additional, Siebesma, A. Pier, additional, Stephan, Claudia Christine, additional, Sullivan, Peter, additional, Touzé-Peiffer, Ludovic, additional, Vial, Jessica, additional, Vogel, Raphaela, additional, Zuidema, Paquita, additional, Alexander, Nicola, additional, Alves, Lyndon, additional, Arixi, Sophian, additional, Asmath, Hamish, additional, Bagheri, Gholamhossein, additional, Baier, Katharina, additional, Bailey, Adriana, additional, Baranowski, Dariusz, additional, Baron, Alexandre, additional, Barrau, Sébastien, additional, Barrett, Paul A., additional, Batier, Frédéric, additional, Behrendt, Andreas, additional, Bendinger, Arne, additional, Beucher, Florent, additional, Bigorre, Sebastien, additional, Blades, Edmund, additional, Blossey, Peter, additional, Bock, Olivier, additional, Böing, Steven, additional, Bosser, Pierre, additional, Bourras, Denis, additional, Bouruet-Aubertot, Pascale, additional, Bower, Keith, additional, Branellec, Pierre, additional, Branger, Hubert, additional, Brennek, Michal, additional, Brewer, Alan, additional, Brilouet, Pierre-Etienne, additional, Brügmann, Björn, additional, Buehler, Stefan A., additional, Burke, Elmo, additional, Burton, Ralph, additional, Calmer, Radiance, additional, Canonici, Jean-Christophe, additional, Carton, Xavier, additional, Cato Jr., Gregory, additional, Charles, Jude Andre, additional, Chazette, Patrick, additional, Chen, Yanxu, additional, Chilinski, Michal T., additional, Choularton, Thomas, additional, Chuang, Patrick, additional, Clarke, Shamal, additional, Coe, Hugh, additional, Cornet, Céline, additional, Coutris, Pierre, additional, Couvreux, Fleur, additional, Crewell, Susanne, additional, Cronin, Timothy, additional, Cui, Zhiqiang, additional, Cuypers, Yannis, additional, Daley, Alton, additional, Damerell, Gillian M., additional, Dauhut, Thibaut, additional, Deneke, Hartwig, additional, Desbios, Jean-Philippe, additional, Dörner, Steffen, additional, Donner, Sebastian, additional, Douet, Vincent, additional, Drushka, Kyla, additional, Dütsch, Marina, additional, Ehrlich, André, additional, Emanuel, Kerry, additional, Emmanouilidis, Alexandros, additional, Etienne, Jean-Claude, additional, Etienne-Leblanc, Sheryl, additional, Faure, Ghislain, additional, Feingold, Graham, additional, Ferrero, Luca, additional, Fix, Andreas, additional, Flamant, Cyrille, additional, Flatau, Piotr Jacek, additional, Foltz, Gregory R., additional, Forster, Linda, additional, Furtuna, Iulian, additional, Gadian, Alan, additional, Galewsky, Joseph, additional, Gallagher, Martin, additional, Gallimore, Peter, additional, Gaston, Cassandra, additional, Gentemann, Chelle, additional, Geyskens, Nicolas, additional, Giez, Andreas, additional, Gollop, John, additional, Gouirand, Isabelle, additional, Gourbeyre, Christophe, additional, de Graaf, Dörte, additional, de Groot, Geiske E., additional, Grosz, Robert, additional, Güttler, Johannes, additional, Gutleben, Manuel, additional, Hall, Kashawn, additional, Harris, George, additional, Helfer, Kevin C., additional, Henze, Dean, additional, Herbert, Calvert, additional, Holanda, Bruna, additional, Ibanez-Landeta, Antonio, additional, Intrieri, Janet, additional, Iyer, Suneil, additional, Julien, Fabrice, additional, Kalesse, Heike, additional, Kazil, Jan, additional, Kellman, Alexander, additional, Kidane, Abiel T., additional, Kirchner, Ulrike, additional, Klingebiel, Marcus, additional, Körner, Mareike, additional, Kremper, Leslie Ann, additional, Kretzschmar, Jan, additional, Krüger, Ovid, additional, Kumala, Wojciech, additional, Kurz, Armin, additional, L'Hégaret, Pierre, additional, Labaste, Matthieu, additional, Lachlan-Cope, Tom, additional, Laing, Arlene, additional, Landschützer, Peter, additional, Lang, Theresa, additional, Lange, Diego, additional, Lange, Ingo, additional, Laplace, Clément, additional, Lavik, Gauke, additional, Laxenaire, Rémi, additional, Le Bihan, Caroline, additional, Leandro, Mason, additional, Lefevre, Nathalie, additional, Lena, Marius, additional, Lenschow, Donald, additional, Li, Qiang, additional, Lloyd, Gary, additional, Los, Sebastian, additional, Losi, Niccolò, additional, Lovell, Oscar, additional, Luneau, Christopher, additional, Makuch, Przemyslaw, additional, Malinowski, Szymon, additional, Manta, Gaston, additional, Marinou, Eleni, additional, Marsden, Nicholas, additional, Masson, Sebastien, additional, Maury, Nicolas, additional, Mayer, Bernhard, additional, Mayers-Als, Margarette, additional, Mazel, Christophe, additional, McGeary, Wayne, additional, McWilliams, James C., additional, Mech, Mario, additional, Mehlmann, Melina, additional, Meroni, Agostino Niyonkuru, additional, Mieslinger, Theresa, additional, Minikin, Andreas, additional, Minnett, Peter, additional, Möller, Gregor, additional, Morfa Avalos, Yanmichel, additional, Muller, Caroline, additional, Musat, Ionela, additional, Napoli, Anna, additional, Neuberger, Almuth, additional, Noisel, Christophe, additional, Noone, David, additional, Nordsiek, Freja, additional, Nowak, Jakub L., additional, Oswald, Lothar, additional, Parker, Douglas J., additional, Peck, Carolyn, additional, Person, Renaud, additional, Philippi, Miriam, additional, Plueddemann, Albert, additional, Pöhlker, Christopher, additional, Pörtge, Veronika, additional, Pöschl, Ulrich, additional, Pologne, Lawrence, additional, Posyniak, Michał, additional, Prange, Marc, additional, Quiñones Meléndez, Estefanía, additional, Radtke, Jule, additional, Ramage, Karim, additional, Reimann, Jens, additional, Renault, Lionel, additional, Reus, Klaus, additional, Reyes, Ashford, additional, Ribbe, Joachim, additional, Ringel, Maximilian, additional, Ritschel, Markus, additional, Rocha, Cesar B., additional, Rochetin, Nicolas, additional, Röttenbacher, Johannes, additional, Rollo, Callum, additional, Royer, Haley, additional, Sadoulet, Pauline, additional, Saffin, Leo, additional, Sandiford, Sanola, additional, Sandu, Irina, additional, Schäfer, Michael, additional, Schemann, Vera, additional, Schirmacher, Imke, additional, Schlenczek, Oliver, additional, Schmidt, Jerome, additional, Schröder, Marcel, additional, Schwarzenboeck, Alfons, additional, Sealy, Andrea, additional, Senff, Christoph J., additional, Serikov, Ilya, additional, Shohan, Samkeyat, additional, Siddle, Elizabeth, additional, Smirnov, Alexander, additional, Späth, Florian, additional, Spooner, Branden, additional, Stolla, M. Katharina, additional, Szkółka, Wojciech, additional, de Szoeke, Simon P., additional, Tarot, Stéphane, additional, Tetoni, Eleni, additional, Thompson, Elizabeth, additional, Thomson, Jim, additional, Tomassini, Lorenzo, additional, Totems, Julien, additional, Ubele, Alma Anna, additional, Villiger, Leonie, additional, von Arx, Jan, additional, Wagner, Thomas, additional, Walther, Andi, additional, Webber, Ben, additional, Wendisch, Manfred, additional, Whitehall, Shanice, additional, Wiltshire, Anton, additional, Wing, Allison A., additional, Wirth, Martin, additional, Wiskandt, Jonathan, additional, Wolf, Kevin, additional, Worbes, Ludwig, additional, Wright, Ethan, additional, Wulfmeyer, Volker, additional, Young, Shanea, additional, Zhang, Chidong, additional, Zhang, Dongxiao, additional, Ziemen, Florian, additional, Zinner, Tobias, additional, and Zöger, Martin, additional

Published
2021
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27. EUREC4A

Author

Stevens, Bjorn, Bony, Sandrine, Farrell, David, Ament, Felix, Blyth, Alan, Fairall, Christopher, Karstensen, Johannes, Quinn, Patricia K., Speich, Sabrina, Acquistapace, Claudia, Aemisegger, Franziska, Albright, Anna Lea, Bellenger, Hugo, Bodenschatz, Eberhard, Caesar, Kathy-ann, Chewitt-lucas, Rebecca, De Boer, Gijs, Delanoe, Julien, Denby, Leif, Ewald, Florian, Fildier, Benjamin, Forde, Marvin, George, Geet, Gross, Silke, Hagen, Martin, Hausold, Andrea, Heywood, Karen J., Hirsch, Lutz, Jacob, Marek, Jansen, Friedhelm, Kinne, Stefan, Klocke, Daniel, Kolling, Tobias, Konow, Heike, Lothon, Marie, Mohr, Wiebke, Naumann, Ann Kristin, Nuijens, Louise, Olivier, Lea, Pincus, Robert, Pohlker, Mira, Reverdin, Gilles, Roberts, Gregory, Schnitt, Sabrina, Schulz, Hauke, Siebesma, A. Pier, Stephan, Claudia Christine, Sullivan, Peter, Touze-peiffer, Ludovic, Vial, Jessica, Vogel, Raphaela, Zuidema, Paquita, Alexander, Nicola, Alves, Lyndon, Arixi, Sophian, Asmath, Hamish, Bagheri, Gholamhossein, Baier, Katharina, Bailey, Adriana, Baranowski, Dariusz, Baron, Alexandre, Barrau, Sebastien, Barrett, Paul A., Batier, Frederic, Behrendt, Andreas, Bendinger, Arne, Beucher, Florent, Bigorre, Sebastien, Blades, Edmund, Blossey, Peter, Bock, Olivier, Boing, Steven, Bosser, Pierre, Bourras, Denis, Bouruet-aubertot, Pascale, Bower, Keith, Branellec, Pierre, Branger, Hubert, Brennek, Michal, Brewer, Alan, Brilouet, Pierre Etienne, Brugmann, Bjorn, Buehler, Stefan A., Burke, Elmo, Burton, Ralph, Calmer, Radiance, Canonici, Jean-christophe, Carton, Xavier, Cato, Gregory, Jr., Charles, Jude Andre, Chazette, Patrick, Chen, Yanxu, Chilinski, Michal T., Choularton, Thomas, Chuang, Patrick, Clarke, Shamal, Coe, Hugh, Cornet, Celine, Coutris, Pierre, Couvreux, Fleur, Crewell, Susanne, Cronin, Timothy, Cui, Zhiqiang, Cuypers, Yannis, Daley, Alton, Damerell, Gillian M., Dauhut, Thibaut, Deneke, Hartwig, Desbios, Jean-philippe, Dorner, Steffen, Donner, Sebastian, Douet, Vincent, Drushka, Kyla, Dutsch, Marina, Ehrlich, Andre, Emanuel, Kerry, Emmanouilidis, Alexandros, Etienne, Jean-claude, Etienne-leblanc, Sheryl, Faure, Ghislain, Feingold, Graham, Ferrero, Luca, Fix, Andreas, Flamant, Cyrille, Flatau, Piotr Jacek, Foltz, Gregory R., Forster, Linda, Furtuna, Iulian, Gadian, Alan, Galewsky, Joseph, Gallagher, Martin, Gallimore, Peter, Gaston, Cassandra, Gentemann, Chelle, Geyskens, Nicolas, Giez, Andreas, Gollop, John, Gouirand, Isabelle, Gourbeyre, Christophe, De Graaf, Dorte, De Groot, Geiske E., Grosz, Robert, Guttler, Johannes, Gutleben, Manuel, Hall, Kashawn, Harris, George, Helfer, Kevin C., Henze, Dean, Herbert, Calvert, Holanda, Bruna, Ibanez-landeta, Antonio, Intrieri, Janet, Iyer, Suneil, Julien, Fabrice, Kalesse, Heike, Kazil, Jan, Kellman, Alexander, Kidane, Abiel T., Kirchner, Ulrike, Klingebiel, Marcus, Korner, Mareike, Kremper, Leslie Ann, Kretzschmar, Jan, Kruger, Ovid, Kumala, Wojciech, Kurz, Armin, L'Hegaret, Pierre, Labaste, Matthieu, Lachlan-cope, Tom, Laing, Arlene, Landschutzer, Peter, Lang, Theresa, Lange, Diego, Lange, Ingo, Laplace, Clement, Lavik, Gauke, Laxenaire, Remi, Le Bihan, Caroline, Leandro, Mason, Lefevre, Nathalie, Lena, Marius, Lenschow, Donald, Li, Qiang, Lloyd, Gary, Los, Sebastian, Losi, Niccolo, Lovell, Oscar, Luneau, Christopher, Makuch, Przemyslaw, Malinowski, Szymon, Manta, Gaston, Marinou, Eleni, Marsden, Nicholas, Masson, Sebastien, Maury, Nicolas, Mayer, Bernhard, Mayers-als, Margarette, Mazel, Christophe, Mcgeary, Wayne, Mcwilliams, James C., Mech, Mario, Mehlmann, Melina, Meroni, Agostino Niyonkuru, Mieslinger, Theresa, Minikin, Andreas, Minnett, Peter, Moller, Gregor, Avalos, Yanmichel Morfa, Muller, Caroline, Musat, Ionela, Napoli, Anna, Neuberger, Almuth, Noisel, Christophe, Noone, David, Nordsiek, Freja, Nowak, Jakub L., Oswald, Lothar, Parker, Douglas J., Peck, Carolyn, Person, Renaud, Philippi, Miriam, Plueddemann, Albert, Pohlker, Christopher, Portge, Veronika, Poschl, Ulrich, Pologne, Lawrence, Posyniak, Michal, Prange, Marc, Melendez, Estefania Quinones, Radtke, Jule, Ramage, Karim, Reimann, Jens, Renault, Lionel, Reus, Klaus, Reyes, Ashford, Ribbe, Joachim, Ringel, Maximilian, Ritschel, Markus, Rocha, Cesar B., Rochetin, Nicolas, Rottenbacher, Johannes, Rollo, Callum, Royer, Haley, Sadoulet, Pauline, Saffin, Leo, Sandiford, Sanola, Sandu, Irina, Schafer, Michael, Schemann, Vera, Schirmacher, Imke, Schlenczek, Oliver, Schmidt, Jerome, Schroder, Marcel, Schwarzenboeck, Alfons, Sealy, Andrea, Senff, Christoph J., Serikov, Ilya, Shohan, Samkeyat, Siddle, Elizabeth, Smirnov, Alexander, Spath, Florian, Spooner, Branden, Stolla, M. Katharina, Szkolka, Wojciech, De Szoeke, Simon P., Tarot, Stephane, Tetoni, Eleni, Thompson, Elizabeth, Thomson, Jim, Tomassini, Lorenzo, Totems, Julien, Ubele, Alma Anna, Villiger, Leonie, Von Arx, Jan, Wagner, Thomas, Walther, Andi, Webber, Ben, Wendisch, Manfred, Whitehall, Shanice, Wiltshire, Anton, Wing, Allison A., Wirth, Martin, Wiskandt, Jonathan, Wolf, Kevin, Worbes, Ludwig, Wright, Ethan, Wulfmeyer, Volker, Young, Shanea, Zhang, Chidong, Zhang, Dongxiao, Ziemen, Florian, Zinner, Tobias, Zoger, Martin, Stevens, Bjorn, Bony, Sandrine, Farrell, David, Ament, Felix, Blyth, Alan, Fairall, Christopher, Karstensen, Johannes, Quinn, Patricia K., Speich, Sabrina, Acquistapace, Claudia, Aemisegger, Franziska, Albright, Anna Lea, Bellenger, Hugo, Bodenschatz, Eberhard, Caesar, Kathy-ann, Chewitt-lucas, Rebecca, De Boer, Gijs, Delanoe, Julien, Denby, Leif, Ewald, Florian, Fildier, Benjamin, Forde, Marvin, George, Geet, Gross, Silke, Hagen, Martin, Hausold, Andrea, Heywood, Karen J., Hirsch, Lutz, Jacob, Marek, Jansen, Friedhelm, Kinne, Stefan, Klocke, Daniel, Kolling, Tobias, Konow, Heike, Lothon, Marie, Mohr, Wiebke, Naumann, Ann Kristin, Nuijens, Louise, Olivier, Lea, Pincus, Robert, Pohlker, Mira, Reverdin, Gilles, Roberts, Gregory, Schnitt, Sabrina, Schulz, Hauke, Siebesma, A. Pier, Stephan, Claudia Christine, Sullivan, Peter, Touze-peiffer, Ludovic, Vial, Jessica, Vogel, Raphaela, Zuidema, Paquita, Alexander, Nicola, Alves, Lyndon, Arixi, Sophian, Asmath, Hamish, Bagheri, Gholamhossein, Baier, Katharina, Bailey, Adriana, Baranowski, Dariusz, Baron, Alexandre, Barrau, Sebastien, Barrett, Paul A., Batier, Frederic, Behrendt, Andreas, Bendinger, Arne, Beucher, Florent, Bigorre, Sebastien, Blades, Edmund, Blossey, Peter, Bock, Olivier, Boing, Steven, Bosser, Pierre, Bourras, Denis, Bouruet-aubertot, Pascale, Bower, Keith, Branellec, Pierre, Branger, Hubert, Brennek, Michal, Brewer, Alan, Brilouet, Pierre Etienne, Brugmann, Bjorn, Buehler, Stefan A., Burke, Elmo, Burton, Ralph, Calmer, Radiance, Canonici, Jean-christophe, Carton, Xavier, Cato, Gregory, Jr., Charles, Jude Andre, Chazette, Patrick, Chen, Yanxu, Chilinski, Michal T., Choularton, Thomas, Chuang, Patrick, Clarke, Shamal, Coe, Hugh, Cornet, Celine, Coutris, Pierre, Couvreux, Fleur, Crewell, Susanne, Cronin, Timothy, Cui, Zhiqiang, Cuypers, Yannis, Daley, Alton, Damerell, Gillian M., Dauhut, Thibaut, Deneke, Hartwig, Desbios, Jean-philippe, Dorner, Steffen, Donner, Sebastian, Douet, Vincent, Drushka, Kyla, Dutsch, Marina, Ehrlich, Andre, Emanuel, Kerry, Emmanouilidis, Alexandros, Etienne, Jean-claude, Etienne-leblanc, Sheryl, Faure, Ghislain, Feingold, Graham, Ferrero, Luca, Fix, Andreas, Flamant, Cyrille, Flatau, Piotr Jacek, Foltz, Gregory R., Forster, Linda, Furtuna, Iulian, Gadian, Alan, Galewsky, Joseph, Gallagher, Martin, Gallimore, Peter, Gaston, Cassandra, Gentemann, Chelle, Geyskens, Nicolas, Giez, Andreas, Gollop, John, Gouirand, Isabelle, Gourbeyre, Christophe, De Graaf, Dorte, De Groot, Geiske E., Grosz, Robert, Guttler, Johannes, Gutleben, Manuel, Hall, Kashawn, Harris, George, Helfer, Kevin C., Henze, Dean, Herbert, Calvert, Holanda, Bruna, Ibanez-landeta, Antonio, Intrieri, Janet, Iyer, Suneil, Julien, Fabrice, Kalesse, Heike, Kazil, Jan, Kellman, Alexander, Kidane, Abiel T., Kirchner, Ulrike, Klingebiel, Marcus, Korner, Mareike, Kremper, Leslie Ann, Kretzschmar, Jan, Kruger, Ovid, Kumala, Wojciech, Kurz, Armin, L'Hegaret, Pierre, Labaste, Matthieu, Lachlan-cope, Tom, Laing, Arlene, Landschutzer, Peter, Lang, Theresa, Lange, Diego, Lange, Ingo, Laplace, Clement, Lavik, Gauke, Laxenaire, Remi, Le Bihan, Caroline, Leandro, Mason, Lefevre, Nathalie, Lena, Marius, Lenschow, Donald, Li, Qiang, Lloyd, Gary, Los, Sebastian, Losi, Niccolo, Lovell, Oscar, Luneau, Christopher, Makuch, Przemyslaw, Malinowski, Szymon, Manta, Gaston, Marinou, Eleni, Marsden, Nicholas, Masson, Sebastien, Maury, Nicolas, Mayer, Bernhard, Mayers-als, Margarette, Mazel, Christophe, Mcgeary, Wayne, Mcwilliams, James C., Mech, Mario, Mehlmann, Melina, Meroni, Agostino Niyonkuru, Mieslinger, Theresa, Minikin, Andreas, Minnett, Peter, Moller, Gregor, Avalos, Yanmichel Morfa, Muller, Caroline, Musat, Ionela, Napoli, Anna, Neuberger, Almuth, Noisel, Christophe, Noone, David, Nordsiek, Freja, Nowak, Jakub L., Oswald, Lothar, Parker, Douglas J., Peck, Carolyn, Person, Renaud, Philippi, Miriam, Plueddemann, Albert, Pohlker, Christopher, Portge, Veronika, Poschl, Ulrich, Pologne, Lawrence, Posyniak, Michal, Prange, Marc, Melendez, Estefania Quinones, Radtke, Jule, Ramage, Karim, Reimann, Jens, Renault, Lionel, Reus, Klaus, Reyes, Ashford, Ribbe, Joachim, Ringel, Maximilian, Ritschel, Markus, Rocha, Cesar B., Rochetin, Nicolas, Rottenbacher, Johannes, Rollo, Callum, Royer, Haley, Sadoulet, Pauline, Saffin, Leo, Sandiford, Sanola, Sandu, Irina, Schafer, Michael, Schemann, Vera, Schirmacher, Imke, Schlenczek, Oliver, Schmidt, Jerome, Schroder, Marcel, Schwarzenboeck, Alfons, Sealy, Andrea, Senff, Christoph J., Serikov, Ilya, Shohan, Samkeyat, Siddle, Elizabeth, Smirnov, Alexander, Spath, Florian, Spooner, Branden, Stolla, M. Katharina, Szkolka, Wojciech, De Szoeke, Simon P., Tarot, Stephane, Tetoni, Eleni, Thompson, Elizabeth, Thomson, Jim, Tomassini, Lorenzo, Totems, Julien, Ubele, Alma Anna, Villiger, Leonie, Von Arx, Jan, Wagner, Thomas, Walther, Andi, Webber, Ben, Wendisch, Manfred, Whitehall, Shanice, Wiltshire, Anton, Wing, Allison A., Wirth, Martin, Wiskandt, Jonathan, Wolf, Kevin, Worbes, Ludwig, Wright, Ethan, Wulfmeyer, Volker, Young, Shanea, Zhang, Chidong, Zhang, Dongxiao, Ziemen, Florian, Zinner, Tobias, and Zoger, Martin

Abstract

The science guiding the \EURECA campaign and its measurements are presented. \EURECA comprised roughly five weeks of measurements in the downstream winter trades of the North Atlantic — eastward and south-eastward of Barbados. Through its ability to characterize processes operating across a wide range of scales, \EURECA marked a turning point in our ability to observationally study factors influencing clouds in the trades, how they will respond to warming, and their link to other components of the earth system, such as upper-ocean processes or, or the life-cycle of particulate matter. This characterization was made possible by thousands (2500) of sondes distributed to measure circulations on meso (200 km) and larger (500 km) scales, roughly four hundred hours of flight time by four heavily instrumented research aircraft, four global-ocean class research vessels, an advanced ground-based cloud observatory, a flotilla of autonomous or tethered measurement devices operating in the upper ocean (nearly 10000 profiles), lower atmosphere (continuous profiling), and along the air-sea interface, a network of water stable isotopologue measurements, complemented by special programmes of satellite remote sensing and modeling with a new generation of weather/climate models. In addition to providing an outline of the novel measurements and their composition into a unified and coordinated campaign, the six distinct scientific facets that \EURECA explored — from Brazil Ring Current Eddies to turbulence induced clustering of cloud droplets and its influence on warm-rain formation — are presented along with an overview \EURECA’s outreach activities, environmental impact, and guidelines for scientific practice.

Published
2021
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28. Performance optimization and load-balancing modeling for superparametrization by 3D LES

Author

Oord, G. (Gijs) van den, Chertova, M. (Maria), Jansson, F.R. (Fredrik), Pelupessy, F.I. (Inti), Siebesma, A.P. (Pier), Crommelin, D.T. (Daan), Oord, G. (Gijs) van den, Chertova, M. (Maria), Jansson, F.R. (Fredrik), Pelupessy, F.I. (Inti), Siebesma, A.P. (Pier), and Crommelin, D.T. (Daan)

Abstract

In order to eliminate climate uncertainty w.r.t. cloud and convection parametrizations, superpramaterization (SP) [1] has emerged as one of the possible ways forward. We have implemented (regional) superparametrization of the ECMWF weather model OpenIFS [2] by cloud-resolving, three-dimensional large-eddy simulations. This setup, described in [3], contains a two-way coupling between a global meteorological model that resolves large-scale dynamics, with many local instances of the Dutch Atmospheric Large Eddy Simulation (DALES) [4], resolving cloud and boundary layer physics. The model is currently prohibitively expensive to run over climate or even seasonal time scales, and a global SP requires the allocation of millions of cores. In this paper, we study the performance and scaling behavior of the LES models and the coupling code and present our implemented optimizations. We mimic the observed load imbalance with a simple performance model and present strategies to improve hardware utilization in order to assess the feasibility of a world-covering superparametrization. We conclude that (quasi-)dynamical load-balancing can significantly reduce the runtime for such large-scale systems with wide variability in LES time-stepping speeds.

Published
2021
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29. A Python interface to the Dutch Atmospheric Large-Eddy Simulation

Author

Oord, G. (Gijs) van den, Jansson, F.R. (Fredrik), Pelupessy, F.I. (Inti), Chertova, M. (Maria), Grönqvist, J.H. (Johanna), Siebesma, A.P. (Pier), Crommelin, D.T. (Daan), Oord, G. (Gijs) van den, Jansson, F.R. (Fredrik), Pelupessy, F.I. (Inti), Chertova, M. (Maria), Grönqvist, J.H. (Johanna), Siebesma, A.P. (Pier), and Crommelin, D.T. (Daan)

Abstract

We present a Python interface for the Dutch Atmospheric Large Eddy Simulation (DALES), an existing Fortran code for high-resolution, turbulence-resolving simulation of atmospheric physics. The interface is based on an infrastructure for remote and parallel function calls and makes it possible to use and control the DALES weather simulations from a Python context. The interface is designed within the OMUSE framework, and allows the user to set up and control the simulation, apply perturbations and forcings, collect and analyse data in real time without exposing the user to the details of setting up and running the parallel Fortran DALES code. Another significant possibility is coupling the DALES simulation to other models, for example larger scale numerical weather prediction (NWP) models that can supply realistic lateral boundary conditions. Finally, the Python interface to DALES can serve as an educational tool for exploring weather dynamics, which we demonstrate with an example Jupyter notebook.

Published
2020
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34. DARCLOS: a cloud shadow detection algorithm for TROPOMI.

Author

Trees, Victor, Wang, Ping, Stammes, Piet, Tilstra, Lieuwe G., Donovan, David P., and Siebesma, A. Pier

Subjects
SPECTRAL reflectance, SPACE-based radar, TRACE gases, AIR quality, SPATIAL resolution, ALGORITHMS
Abstract

Cloud shadows are observed by the TROPOMI satellite instrument as a result of its high spatial resolution as compared to its predecessor instruments. These shadows contaminate TROPOMI's air quality measurements, because shadows are generally not taken into account in the models that are used for aerosol and trace gas retrievals. If the shadows are to be removed from the data, or if shadows are to be studied, an automatic detection of the shadow pixels is needed. We present the Detection AlgoRithm for CLOud Shadows (DARCLOS) for TROPOMI, which is the first cloud shadow detection algorithm for a spaceborne spectrometer. DARCLOS raises potential cloud shadow flags (PCSFs), and actual cloud shadow flags (ACSFs). The PCSFs indicate the TROPOMI ground pixels that are potentially affected by cloud shadows based on a geometric consideration with safety margins. The ACSFs are a refinement of the PCSFs using spectral reflectance information of the PCSF pixels, and identify the TROPOMI ground pixels that are confidently affected by cloud shadows. We validate DARCLOS with true color images made by the VIIRS instrument on board of Suomi NPP orbiting in close constellation with TROPOMI on board of Sentinel 5-P. We conclude that the PCSF can be used to exclude cloud shadow contamination from TROPOMI data, while the ACSF can be used to select pixels for the scientific analysis of cloud shadow effects. [ABSTRACT FROM AUTHOR]

Published
2021
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35. On the regional superparametrization of OpenIFS by 3D LES models

Author

Jansson, F.R. (Fredrik), Oord, G. (Gijs) van den, Pelupessy, F.I. (Inti), Chertova, M. (Maria), Siebesma, A.P. (Pier), Crommelin, D.T. (Daan), Jansson, F.R. (Fredrik), Oord, G. (Gijs) van den, Pelupessy, F.I. (Inti), Chertova, M. (Maria), Siebesma, A.P. (Pier), and Crommelin, D.T. (Daan)

Published
2019

36. Creating a reusable cross-disciplinary multi-scale and multi-physics framework: From AMUSE to OMUSE and beyond

Author

Pelupessy, F.I. (Inti), Portegies Zwart, S. (Simon), Van Elteren, A. (Arjen), Dijkstra, H.A., Jansson, F.R. (Fredrik), Crommelin, D.T. (Daan), Siebesma, A.P. (Pier), Werkhoven, B.J.C. (Ben) van, Oord, G. (Gijs) van den, Pelupessy, F.I. (Inti), Portegies Zwart, S. (Simon), Van Elteren, A. (Arjen), Dijkstra, H.A., Jansson, F.R. (Fredrik), Crommelin, D.T. (Daan), Siebesma, A.P. (Pier), Werkhoven, B.J.C. (Ben) van, and Oord, G. (Gijs) van den

Abstract

Here, we describe our efforts to create a multi-scale and multi-physics framework that can be retargeted across different disciplines. Currently we have implemented our approach in the astrophysical domain, for which we developed AMUSE (github.com/amusecode/amuse ), and generalized this to the oceanographic and climate sciences, which led to the development of OMUSE (bitbucket.org/omuse ). The objective of this paper is to document the design choices that led to the successful implementation of these frameworks as well as the future challenges in applying this approach to other domains.

Published
2019
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37. Regional superparameterization in a global circulation model using Large Eddy Simulations

Author

Jansson, F.R. (Fredrik), Oord, G. (Gijs) van den, Pelupessy, F.I. (Inti), Grönqvist, J.H. (Johanna), Siebesma, A.P. (Pier), Crommelin, D.T. (Daan), Jansson, F.R. (Fredrik), Oord, G. (Gijs) van den, Pelupessy, F.I. (Inti), Grönqvist, J.H. (Johanna), Siebesma, A.P. (Pier), and Crommelin, D.T. (Daan)

Abstract

As a computationally attractive alternative for global large eddy simulations (LESs), we investigate the possibility of using comprehensive three‐dimensional LESs as a superparameterization that can replace all traditional parameterizations of atmospheric processes that are currently used in global models. We present the technical design for a replacement of the parameterization for clouds, convection, and turbulence of the global atmospheric model of the European Centre for Medium‐Range Weather Forecasts by the Dutch Atmospheric Large Eddy Simulation model. The model coupling consists of bidirectional data exchange between the global model and the high‐resolution LES models embedded within the columns of the global model. Our setup allows for selective superparameterization, that is, for applying superparameterization in local regions selected by the user, while keeping the standard parameterization of the global model intact outside this region. Computationally, this setup can result in major geographic load imbalance, because of the large difference in computational load between superparameterized and nonsuperparameterized model columns. To resolve this issue, we use a modular design where the local and global models are kept as distinct model codes and organize the model coupling such that all the local models run in parallel, separate from the global model. First simulation results, employing this design, demonstrate the potential of our approach.

Published
2019
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38. Turbulent Transport in the Gray Zone: A Large Eddy Model Intercomparison Study of the CONSTRAIN Cold Air Outbreak Case

Author

Roode, Stephan R., Frederikse, Thomas, Siebesma, A. Pier, Ackerman, Andrew S., Chylik, Jan, Field, Paul R., Fricke, Jens, Gryschka, Micha, Hill, Adrian, Honnert, Rachel, Krueger, Steve K., Lac, Christine, Lesage, Andrew T., Tomassini, Lorenzo, Roode, Stephan R., Frederikse, Thomas, Siebesma, A. Pier, Ackerman, Andrew S., Chylik, Jan, Field, Paul R., Fricke, Jens, Gryschka, Micha, Hill, Adrian, Honnert, Rachel, Krueger, Steve K., Lac, Christine, Lesage, Andrew T., and Tomassini, Lorenzo

Published
2019

39. Turbulent transport in the Gray Zone: A large-eddy model intercomparison study of the CONSTRAIN cold air outbreak case.

Author

de Roode, Stephan R., Frederikse, Thomas, Siebesma, A. Pier, Ackerman, Andrew S., Chylik, Jan, Field, Paul R., Fricke, Jens, Gryschka, Micha, Hill, Adrian, Honnert, Rachel, Krueger, Steven K., Lac, Christine, Lesage, Andrew T., Tomassini, Lorenzo, de Roode, Stephan R., Frederikse, Thomas, Siebesma, A. Pier, Ackerman, Andrew S., Chylik, Jan, Field, Paul R., Fricke, Jens, Gryschka, Micha, Hill, Adrian, Honnert, Rachel, Krueger, Steven K., Lac, Christine, Lesage, Andrew T., and Tomassini, Lorenzo

Abstract

To quantify the turbulent transport at gray zone length scales between 1 and 10 km, the Lagrangian evolution of the CONSTRAIN cold air outbreak case was simulated with seven large eddy models. The case is characterized by rather large latent and sensible heat fluxes and a rapid deepening rate of the boundary layer. In some models the entrainment velocity exceeds 4 cm/s. A significant fraction of this growth is attributed to a strong longwave radiative cooling of the inversion layer. The evolution and the timing of the breakup of the stratocumulus cloud deck differ significantly among the models. Sensitivity experiments demonstrate that a decrease in the prescribed cloud droplet number concentration and the inclusion of ice microphysics both act to speed up the thinning of the stratocumulus by enhancing the production of precipitation. In all models the formation of mesoscale fluctuations is clearly evident in the cloud fields and also in the horizontal wind velocity. Resolved vertical fluxes remain important for scales up to 10 km. The simulation results show that the resolved vertical velocity variance gradually diminishes with a coarsening of the horizontal mesh, but the total vertical fluxes of heat, moisture, and momentum are only weakly affected. This is a promising result as it demonstrates the potential use of a mesh size‐dependent turbulent length scale for convective boundary layers at gray zone model resolutions.

Published
2019

45. The Cloud Feedback Model Intercomparison Project (CFMIP) contribution to CMIP6

Author

Webb, Mark J., primary, Andrews, Timothy, additional, Bodas-Salcedo, Alejandro, additional, Bony, Sandrine, additional, Bretherton, Christopher S., additional, Chadwick, Robin, additional, Chepfer, Hélène, additional, Douville, Hervé, additional, Good, Peter, additional, Kay, Jennifer E., additional, Klein, Stephen A., additional, Marchand, Roger, additional, Medeiros, Brian, additional, Siebesma, A. Pier, additional, Skinner, Christopher B., additional, Stevens, Bjorn, additional, Tselioudis, George, additional, Tsushima, Yoko, additional, and Watanabe, Masahiro, additional

Published
2017
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47. Response of Extreme Precipitating Cell Structures to Atmospheric Warming.

Author

Lenderink, Geert, Lochbihler, Kai, and Siebesma, A. Pier

Subjects
TEMPERATURE, METEOROLOGICAL precipitation, CLAUSIUS-Clapeyron relation, HUMIDITY, GLOBAL warming
Abstract

With increasing temperatures, it is likely that precipitation extremes increase as well. While, on larger spatial and longer temporal scales, the amplification of rainfall extremes often follows the Clausius‐Clapeyron relation, it has been shown that local short‐term convective precipitation extremes may well exceed the Clausius‐Clapeyron rate of around 6.5%/K. Most studies on this topic have focused exclusively on the intensity aspect, while only few have examined (with contradictory results) how warmer and moister conditions modulate the spatial characteristics of convective precipitation extremes and how these connect to increased intensities. Here we study this relation by using a large eddy simulation model. We simulate one diurnal cycle of heavy convective precipitation activity based on a realistic observation‐based strongly forced case setup. Systematically perturbed initial conditions of temperature and specific humidity enable an examination of the response of intensities and spatial characteristics of the precipitation field over an 8° dew point temperature range. We find that warmer and moister conditions result in an overall increase of both intensities and spatial extent of individual rain cells. Colder conditions favor the development of many but smaller rain cells. Under warmer conditions, we find a reduced number of individual cells, but their size significantly grows along with an increase of intensities over a large part of a rain cell. Combined, these factors lead to larger and more intense rain cells that can produce up to almost 20% more rain per degree warming and therefore have a large impact. Key Points: Warmer and moister conditions reshape the precipitation field to fewer but larger rain cellsLarger rain cells produce more intense rainRain rates aggregated over a rain cell can increase by up to almost 20% per degree warming [ABSTRACT FROM AUTHOR]

Published
2019
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48. Evaluation of statistical cloud parameterizations

Author

Quaas, Johannes, Siebesma, A. Pier, Universität Leipzig, Brück, Heiner Matthias, Quaas, Johannes, Siebesma, A. Pier, Universität Leipzig, and Brück, Heiner Matthias

Abstract

This work is motivated by the question: how much complexity is appropriate for a cloud parameterization used in general circulation models (GCM). To approach this question, cloud parameterizations across the complexity range are explored using general circulation models and theoretical Monte-Carlo simulations. Their results are compared with high-resolution satellite observations and simulations that resolve the GCM subgrid-scale variability explicitly. A process-orientated evaluation is facilitated by GCM forecast simulations which reproduce the synoptic state. For this purpose novel methods were develop to a) conceptually relate the underlying saturation deficit probability density function (PDF) with its saturated cloudy part, b) analytically compute the vertical integrated liquid water path (LWP) variability, c) diagnose the relevant PDF-moments from cloud parameterizations, d) derive high-resolution LWP from satellite observations and e) deduce the LWP statistics by aggregating the LWP onto boxes equivalent to the GCM grid size. On this basis, this work shows that it is possible to evaluate the sub-grid scale variability of cloud parameterizations in terms of cloud variables. Differences among the PDF types increase with complexity, in particular the more advanced cloud parameterizations can make use of their double Gaussian PDF in conditions, where cumulus convection forms a separate mode with respect to the remainder of the grid-box. Therefore, it is concluded that the difference between unimodal and bimodal PDFs is more important, than the shape within each mode. However, the simulations and their evaluation reveals that the advanced parameterizations do not take full advantage of their abilities and their statistical relationships are broadly similar to less complex PDF shapes, while the results from observations and cloud resolving simulations indicate even more complex distributions. Therefore, this work suggests that the use of less complex PDF shapes mi

Published
2016

49. Evaluation of statistical cloud parameterizations

Author

Siebesma, A. Pier, Universität Leipzig, Brück, Heiner Matthias, Siebesma, A. Pier, Universität Leipzig, and Brück, Heiner Matthias

Abstract

This work is motivated by the question: how much complexity is appropriate for a cloud parameterization used in general circulation models (GCM). To approach this question, cloud parameterizations across the complexity range are explored using general circulation models and theoretical Monte-Carlo simulations. Their results are compared with high-resolution satellite observations and simulations that resolve the GCM subgrid-scale variability explicitly. A process-orientated evaluation is facilitated by GCM forecast simulations which reproduce the synoptic state. For this purpose novel methods were develop to a) conceptually relate the underlying saturation deficit probability density function (PDF) with its saturated cloudy part, b) analytically compute the vertical integrated liquid water path (LWP) variability, c) diagnose the relevant PDF-moments from cloud parameterizations, d) derive high-resolution LWP from satellite observations and e) deduce the LWP statistics by aggregating the LWP onto boxes equivalent to the GCM grid size. On this basis, this work shows that it is possible to evaluate the sub-grid scale variability of cloud parameterizations in terms of cloud variables. Differences among the PDF types increase with complexity, in particular the more advanced cloud parameterizations can make use of their double Gaussian PDF in conditions, where cumulus convection forms a separate mode with respect to the remainder of the grid-box. Therefore, it is concluded that the difference between unimodal and bimodal PDFs is more important, than the shape within each mode. However, the simulations and their evaluation reveals that the advanced parameterizations do not take full advantage of their abilities and their statistical relationships are broadly similar to less complex PDF shapes, while the results from observations and cloud resolving simulations indicate even more complex distributions. Therefore, this work suggests that the use of less complex PDF shapes mi

Published
2016

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