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107 results on '"Canut, Guylaine"'

2. The Pyrenean Platform for Observation of the Atmosphere: Site, long-term dataset and science

Author

Lothon, Marie, primary, Gheusi, François, additional, Lohou, Fabienne, additional, Pont, Véronique, additional, Soula, Serge, additional, Derrien, Solène, additional, Bezombes, Yannick, additional, Leclerc, Emmanuel, additional, Athier, Gilles, additional, Vial, Antoine, additional, Philibert, Alban, additional, Campistron, Bernard, additional, Saïd, Frédérique, additional, Jambert, Corinne, additional, Sonke, Jeroen, additional, Amestoy, Julien, additional, Bargain, Erwan, additional, Bosser, Pierre, additional, Boulanger, Damien, additional, Bret, Guillaume, additional, Bodichon, Renaud, additional, Cabanas, Laurent, additional, Canut, Guylaine, additional, Estrampes, Jean-Bernard, additional, Gardrat, Eric, additional, Gomez Kuri, Zaida, additional, Gueffier, Jérémy, additional, Guesdon, Fabienne, additional, Lopez, Morgan, additional, Masson, Olivier, additional, Meslin, Pierre-Yves, additional, Meyerfeld, Yves, additional, Pascal, Nicolas, additional, Pique, Eric, additional, Ramonet, Michel, additional, Starck, Felix, additional, and Vidal, Romain, additional

Published
2024
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7. Evaluation of the representativity of reference long-term surface flux measurements in an heterogeneous landscape : the Météopole campaign (MOSAI project)

Author

Jomé, Mathilde, primary, Lohou, Fabienne, additional, Lothon, Marie, additional, Canut, Guylaine, additional, Couvreux, Fleur, additional, Brut, Aurore, additional, Derrien, Solène, additional, Maurel, William, additional, Etienne, Jean-Claude, additional, Vial, Antoine, additional, and Garrouste, Olivier, additional

Published
2023
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8. HyMeX-SOP2 : The Field Campaign Dedicated to Dense Water Formation in the Northwestern Mediterranean

Author

Estournel, Claude, Testor, Pierre, Taupier-Letage, Isabelle, Bouin, Marie-Noelle, Coppola, Laurent, Durand, Pierre, Conan, Pascal, Bosse, Anthony, Brilouet, Pierre-Etienne, Beguery, Laurent, Belamari, Sophie, Béranger, Karine, Beuvier, Jonathan, Bourras, Denis, Canut, Guylaine, Doerenbecher, Alexis, de Madron, Xavier Durrieu, D'Ortenzio, Fabrizio, Drobinski, Philippe, Ducrocq, Véronique, Fourrié, Nadia, Giordani, Hervé, Houpert, Loïc, Labatut, Laurent, Brossier, Cindy Lebeaupin, Nuret, Mathieu, Prieur, Louis, Roussot, Odile, Seyfried, Leo, and Somot, Samuel

Published
2016

9. Role of thermodynamic and turbulence processes on the fog life cycle during SOFOF3D experiment

Author

Dione, Cheikh, Haeffelin, Martial, Burnet, Frédéric, Lac, Christine, Canut, Guylaine, Delanoë, Julien, Dupont, Jean-Charles, Jorquera, Susana, Martinet, Pauline, Ribaud, Jean-François, and Toledo, Felipe

Abstract

In this study, we use a synergy of in-situ and remote sensing measurements collected during the Southwest FOGs 3D experiment for processes study (SOFOG3D) field campaign in autumn 2019 and winter 2020, to analyze the thermodynamic and turbulence processes related to fog formation, evolution, and dissipation across southwestern France. Based on a unique dataset with a very high resolution and a fog conceptual model, an analysis of the four heaviest fog episodes (two radiation fogs and two advection-radiation fogs) is conducted. The results show that radiation and advection-radiation fogs form under deep and thin temperature inversion, respectively. For both fog categories, the transition period from stable to adiabatic fog and the fog adiabatic phase are driven by vertical mixing associated with an increase in turbulence in the fog layer due to mechanical production (turbulence kinetic energy (TKE) up to 0.4 m2 s-2 and vertical velocity variance (σw2) up to 0.04 m2 s-2) generated by brisk wind at the supersite (advection). The dissipation time is observed at night for the advection-radiation fog case studies and during the day for the radiation fog case studies. Night-time dissipation is driven by horizontal advection generating mechanical turbulence (TKE at least 0.3 m2 s-2 and σw2 larger than 0.04 m2 s-2). Daytime dissipation is linked to the combination of thermal and mechanical turbulence related respectively to solar heating (near surface sensible heat flux larger than 10 W m-2) and advection. Through a deficit of the fog reservoir of liquid water path, the fog conceptual model estimates the dissipation time at least one hour before the observed dissipation for radiation fog cases. It gives a better estimate of the fog dissipation time for advection-radiation cases. This study also demonstrates the importance of using instrumental synergy (with microwave radiometer, wind lidar, weather station, and cloud radar) and a fog conceptual model to better predict fog characteristics and dissipation time at nowcasting ranges.

Published
2023

10. The surface-boundary layer connection across spatial scales of irrigation-driven thermal heterogeneity: An integrated data and modeling study of the LIAISE field campaign

Author

Global Ecohydrology and Sustainability, Environmental Sciences, Mangan, Mary Rose, Hartogensis, Oscar, Boone, Aaron, Branch, Oliver, Canut, Guylaine, Cuxart, Joan, de Boer, Hugo J., Le Page, Michel, Martínez-Villagrasa, Daniel, Miró, Josep Ramon, Price, Jeremy, Vilà-Guerau de Arellano, Jordi, Global Ecohydrology and Sustainability, Environmental Sciences, Mangan, Mary Rose, Hartogensis, Oscar, Boone, Aaron, Branch, Oliver, Canut, Guylaine, Cuxart, Joan, de Boer, Hugo J., Le Page, Michel, Martínez-Villagrasa, Daniel, Miró, Josep Ramon, Price, Jeremy, and Vilà-Guerau de Arellano, Jordi

Published
2023

12. Using artificial neural network to better evaluate surface turbulent heat fluxes in weather and climate numerical models

Author

Zouzoua, maurin, primary, Bastin, Sophie, additional, Chiriaco, Marjolaine, additional, Lothon, Marie, additional, Lohou, Fabienne, additional, Barthès, Laurent, additional, Mallet, Cécile, additional, Derrien, Solène, additional, Cheruy, Frédérique, additional, Bazile, Eric, additional, Polcher, Jan, additional, Roehrig, Romain, additional, and Canut, Guylaine, additional

Published
2022
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15. Intercomparison of Large-Eddy Simulations of the Antarctic Boundary Layer for Very Stable Stratification

Author

Couvreux, Fleur (author), Bazile, Eric (author), Rodier, Quentin (author), Maronga, Björn (author), Matheou, Georgios (author), Chinita, Maria J. (author), Edwards, John (author), van Stratum, Bart J.H. (author), van Heerwaarden, Chiel C. (author), Huang, Jing (author), Moene, Arnold F. (author), Cheng, Anning (author), Fuka, Vladimir (author), Basu, S. (author), Bou-Zeid, Elie (author), Canut, Guylaine (author), Vignon, Etienne (author), Couvreux, Fleur (author), Bazile, Eric (author), Rodier, Quentin (author), Maronga, Björn (author), Matheou, Georgios (author), Chinita, Maria J. (author), Edwards, John (author), van Stratum, Bart J.H. (author), van Heerwaarden, Chiel C. (author), Huang, Jing (author), Moene, Arnold F. (author), Cheng, Anning (author), Fuka, Vladimir (author), Basu, S. (author), Bou-Zeid, Elie (author), Canut, Guylaine (author), and Vignon, Etienne (author)

Abstract

In polar regions, where the boundary layer is often stably stratified, atmospheric models produce large biases depending on the boundary-layer parametrizations and the parametrization of the exchange of energy at the surface. This model intercomparison focuses on the very stable stratification encountered over the Antarctic Plateau in 2009. Here, we analyze results from 10 large-eddy-simulation (LES) codes for different spatial resolutions over 24 consecutive hours, and compare them with observations acquired at the Concordia Research Station during summer. This is a challenging exercise for such simulations since they need to reproduce both the 300-m-deep convective boundary layer and the very thin stable boundary layer characterized by a strong vertical temperature gradient (10 K difference over the lowest 20 m) when the sun is low over the horizon. A large variability in surface fluxes among the different models is highlighted. The LES models correctly reproduce the convective boundary layer in terms of mean profiles and turbulent characteristics but display more spread during stable conditions, which is largely reduced by increasing the horizontal and vertical resolutions in additional simulations focusing only on the stable period. This highlights the fact that very fine resolution is needed to represent such conditions. Complementary sensitivity studies are conducted regarding the roughness length, the subgrid-scale turbulence closure as well as the resolution and domain size. While we find little dependence on the surface-flux parametrization, the results indicate a pronounced sensitivity to both the roughness length and the turbulence closure., Accepted Author Manuscript, Atmospheric Remote Sensing

Published
2020
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16. The SOuth west FOGs 3D experiment for processes study (SOFOG3D) project

Author

Burnet, Frédéric, primary, Lac, Christine, additional, Martinet, Pauline, additional, Fourrié, Nadia, additional, Haeffelin, Martial, additional, Delanoë, Julien, additional, Price, Jeremy, additional, Barrau, Sébastien, additional, Canut, Guylaine, additional, Cayez, Grégoire, additional, Dabas, Alain, additional, Denjean, Cyrielle, additional, Dupont, Jean-Charles, additional, Honnert, Rachel, additional, Mahfouf, Jean-François, additional, Montmerle, Thibault, additional, Roberts, Greg, additional, Seity, Yann, additional, and Vié, Benoit, additional

Published
2020
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19. Early stage litter decomposition across biomes

Author

Djukic, Ika, Kepfer-Rojas, Sebastian, Schmidt, Inger Kappel, Larsen, Klaus Steenberg, Beier, Claus, Berg, Björn, Verheyen, Kris, Caliman, Adriano, Paquette, Alain, Gutiérrez-Girón, Alba, Humber, Alberto, Valdecantos, Alejandro, Petraglia, Alessandro, Alexander, Heather, Augustaitis, Algirdas, Saillard, Amélie, Fernández, Ana Carolina Ruiz, Sousa, Ana I., Lillebø, Ana I., da Rocha Gripp, Anderson, Francez, André-Jean, Fischer, Andrea, Bohner, Andreas, Malyshev, Andrey, Andrić, Andrijana, Smith, Andy, Stanisci, Angela, Seres, Anikó, Schmidt, Anja, Avila, Anna, Probst, Anne, Ouin, Annie, Khuroo, Anzar A., Verstraeten, Arne, Palabral-Aguilera, Arely N., Stefanski, Artur, Gaxiola, Aurora, Muys, Bart, Bosman, Bernard, Ahrends, Bernd, Parker, Bill, Sattler, Birgit, Yang, Bo, Juráni, Bohdan, Erschbamer, Brigitta, Ortiz, Carmen Eugenia Rodriguez, Christiansen, Casper T., Carol Adair, E., Meredieu, Céline, Mony, Cendrine, Nock, Charles A., Chen, Chi-Ling, Wang, Chiao-Ping, Baum, Christel, Rixen, Christian, Delire, Christine, Piscart, Christophe, Andrews, Christopher, Rebmann, Corinna, Branquinho, Cristina, Polyanskaya, Dana, Delgado, David Fuentes, Wundram, Dirk, Radeideh, Diyaa, Ordóñez-Regil, Eduardo, Crawford, Edward, Preda, Elena, Tropina, Elena, Groner, Elli, Lucot, Eric, Hornung, Erzsébet, Gacia, Esperança, Lévesque, Esther, Benedito, Evanilde, Davydov, Evgeny A., Ampoorter, Evy, Bolzan, Fabio Padilha, Varela, Felipe, Kristöfel, Ferdinand, Maestre, Fernando T., Maunoury-Danger, Florence, Hofhansl, Florian, Kitz, Florian, Sutter, Flurin, Cuesta, Francisco, de Almeida Lobo, Francisco, de Souza, Franco Leandro, Berninger, Frank, Zehetner, Franz, Wohlfahrt, Georg, Vourlitis, George, Carreño-Rocabado, Geovana, Arena, Gina, Pinha, Gisele Daiane, González, Grizelle, Canut, Guylaine, Lee, Hanna, Verbeeck, Hans, Auge, Harald, Pauli, Harald, Nacro, Hassan Bismarck, Bahamonde, Héctor A., Feldhaar, Heike, Jäger, Heinke, Serrano, Helena C., Verheyden, Hélène, Bruelheide, Helge, Meesenburg, Henning, Jungkunst, Hermann, Jactel, Hervé, Shibata, Hideaki, Kurokawa, Hiroko, Rosas, Hugo López, Rojas Villalobos, Hugo L., Yesilonis, Ian, Melece, Inara, Van Halder, Inge, Quirós, Inmaculada García, Makelele, Isaac, Senou, Issaka, Fekete, István, Mihal, Ivan, Ostonen, Ivika, Borovská, Jana, Roales, Javier, Shoqeir, Jawad, Lata, Jean-Christophe, Theurillat, Jean-Paul, Probst, Jean-Luc, Zimmerman, Jess, Vijayanathan, Jeyanny, Tang, Jianwu, Thompson, Jill, Doležal, Jiří, Sanchez-Cabeza, Joan-Albert, Merlet, Joël, Henschel, Joh, Neirynck, Johan, Knops, Johannes, Loehr, John, von Oppen, Jonathan, Þorláksdóttir, Jónína Sigríður, Löffler, Jörg, Cardoso-Mohedano, José-Gilberto, Benito-Alonso, José-Luis, Torezan, Jose Marcelo, Morina, Joseph C., Jiménez, Juan J., Quinde, Juan Dario, Alatalo, Juha, Seeber, Julia, Stadler, Jutta, Kriiska, Kaie, Coulibaly, Kalifa, Fukuzawa, Karibu, Szlavecz, Katalin, Gerhátová, Katarína, Lajtha, Kate, Käppeler, Kathrin, Jennings, Katie A., Tielbörger, Katja, Hoshizaki, Kazuhiko, Green, Ken, Yé, Lambiénou, Pazianoto, Laryssa Helena Ribeiro, Dienstbach, Laura, Williams, Laura, Yahdjian, Laura, Brigham, Laurel M., van den Brink, Liesbeth, Rustad, Lindsey, Zhang, Lipeng, Morillas, Lourdes, Xiankai, Lu, Carneiro, Luciana Silva, Di Martino, Luciano, Villar, Luis, Bader, Maaike Y., Morley, Madison, Lebouvier, Marc, Tomaselli, Marcello, Sternberg, Marcelo, Schaub, Marcus, Santos-Reis, Margarida, Glushkova, Maria, Torres, María Guadalupe Almazán, Giroux, Marie-Andrée, de Graaff, Marie-Anne, Pons, Marie-Noëlle, Bauters, Marijn, Mazón, Marina, Frenzel, Mark, Didion, Markus, Wagner, Markus, Hamid, Maroof, Lopes, Marta L., Apple, Martha, Schädler, Martin, Weih, Martin, Gualmini, Matteo, Vadeboncoeur, Matthew A., Bierbaumer, Michael, Danger, Michael, Liddell, Michael, Mirtl, Michael, Scherer-Lorenzen, Michael, Růžek, Michal, Carbognani, Michele, Di Musciano, Michele, Matsushita, Michinari, Zhiyanski, Miglena, Pușcaș, Mihai, Barna, Milan, Ataka, Mioko, Jiangming, Mo, Alsafran, Mohammed, Carnol, Monique, Barsoum, Nadia, Tokuchi, Naoko, Eisenhauer, Nico, Lecomte, Nicolas, Filippova, Nina, Hölzel, Norbert, Ferlian, Olga, Romero, Oscar, Pinto, Osvaldo B., Peri, Pablo, Weber, Paige, Vittoz, Pascal, Turtureanu, Pavel Dan, Fleischer, Peter, Macreadie, Peter, Haase, Peter, Reich, Peter, Petřík, Petr, Choler, Philippe, Marmonier, Pierre, Muriel, Priscilla, Ponette, Quentin, Guariento, Rafael Dettogni, Canessa, Rafaella, Kiese, Ralf, Hewitt, Rebecca, Rønn, Regin, Adrian, Rita, Kanka, Róbert, Weigel, Robert, Gatti, Roberto Cazzolla, Martins, Rodrigo Lemes, Georges, Romain, Meneses, Rosa Isela, Gavilán, Rosario G., Dasgupta, Sabyasachi, Wittlinger, Sally, Puijalon, Sara, Freda, Sarah, Suzuki, Satoshi, Charles, Sean, Gogo, Sébastien, Drollinger, Simon, Mereu, Simone, Wipf, Sonja, Trevathan-Tackett, Stacey, Löfgren, Stefan, Stoll, Stefan, Trogisch, Stefan, Hoeber, Stefanie, Seitz, Steffen, Glatzel, Stephan, Milton, Sue J., Dousset, Sylvie, Mori, Taiki, Sato, Takanori, Ise, Takeshi, Hishi, Takuo, Kenta, Tanaka, Nakaji, Tatsuro, Michelan, Thaisa Sala, Camboulive, Thierry, Mozdzer, Thomas J., Scholten, Thomas, Spiegelberger, Thomas, Zechmeister, Thomas, Kleinebecker, Till, Hiura, Tsutom, Enoki, Tsutomu, Ursu, Tudor-Mihai, di Cella, Umberto Morra, Hamer, Ute, Klaus, Valentin H., Rêgo, Vanessa Mendes, Di Cecco, Valter, Busch, Verena, Fontana, Veronika, Piscová, Veronika, Carbonell, Victoria, Ochoa, Victoria, Bretagnolle, Vincent, Maire, Vincent, Farjalla, Vinicius, Zhou, Wenjun, Luo, Wentao, McDowell, William H., Hu, Yalin, Utsumi, Yasuhiro, Kominami, Yuji, Zaika, Yulia, Rozhkov, Yury, Kotroczó, Zsolt, Tóth, Zsolt, Djukic, Ika, Kepfer-Rojas, Sebastian, Schmidt, Inger Kappel, Larsen, Klaus Steenberg, Beier, Claus, Berg, Björn, Verheyen, Kris, Caliman, Adriano, Paquette, Alain, Gutiérrez-Girón, Alba, Humber, Alberto, Valdecantos, Alejandro, Petraglia, Alessandro, Alexander, Heather, Augustaitis, Algirdas, Saillard, Amélie, Fernández, Ana Carolina Ruiz, Sousa, Ana I., Lillebø, Ana I., da Rocha Gripp, Anderson, Francez, André-Jean, Fischer, Andrea, Bohner, Andreas, Malyshev, Andrey, Andrić, Andrijana, Smith, Andy, Stanisci, Angela, Seres, Anikó, Schmidt, Anja, Avila, Anna, Probst, Anne, Ouin, Annie, Khuroo, Anzar A., Verstraeten, Arne, Palabral-Aguilera, Arely N., Stefanski, Artur, Gaxiola, Aurora, Muys, Bart, Bosman, Bernard, Ahrends, Bernd, Parker, Bill, Sattler, Birgit, Yang, Bo, Juráni, Bohdan, Erschbamer, Brigitta, Ortiz, Carmen Eugenia Rodriguez, Christiansen, Casper T., Carol Adair, E., Meredieu, Céline, Mony, Cendrine, Nock, Charles A., Chen, Chi-Ling, Wang, Chiao-Ping, Baum, Christel, Rixen, Christian, Delire, Christine, Piscart, Christophe, Andrews, Christopher, Rebmann, Corinna, Branquinho, Cristina, Polyanskaya, Dana, Delgado, David Fuentes, Wundram, Dirk, Radeideh, Diyaa, Ordóñez-Regil, Eduardo, Crawford, Edward, Preda, Elena, Tropina, Elena, Groner, Elli, Lucot, Eric, Hornung, Erzsébet, Gacia, Esperança, Lévesque, Esther, Benedito, Evanilde, Davydov, Evgeny A., Ampoorter, Evy, Bolzan, Fabio Padilha, Varela, Felipe, Kristöfel, Ferdinand, Maestre, Fernando T., Maunoury-Danger, Florence, Hofhansl, Florian, Kitz, Florian, Sutter, Flurin, Cuesta, Francisco, de Almeida Lobo, Francisco, de Souza, Franco Leandro, Berninger, Frank, Zehetner, Franz, Wohlfahrt, Georg, Vourlitis, George, Carreño-Rocabado, Geovana, Arena, Gina, Pinha, Gisele Daiane, González, Grizelle, Canut, Guylaine, Lee, Hanna, Verbeeck, Hans, Auge, Harald, Pauli, Harald, Nacro, Hassan Bismarck, Bahamonde, Héctor A., Feldhaar, Heike, Jäger, Heinke, Serrano, Helena C., Verheyden, Hélène, Bruelheide, Helge, Meesenburg, Henning, Jungkunst, Hermann, Jactel, Hervé, Shibata, Hideaki, Kurokawa, Hiroko, Rosas, Hugo López, Rojas Villalobos, Hugo L., Yesilonis, Ian, Melece, Inara, Van Halder, Inge, Quirós, Inmaculada García, Makelele, Isaac, Senou, Issaka, Fekete, István, Mihal, Ivan, Ostonen, Ivika, Borovská, Jana, Roales, Javier, Shoqeir, Jawad, Lata, Jean-Christophe, Theurillat, Jean-Paul, Probst, Jean-Luc, Zimmerman, Jess, Vijayanathan, Jeyanny, Tang, Jianwu, Thompson, Jill, Doležal, Jiří, Sanchez-Cabeza, Joan-Albert, Merlet, Joël, Henschel, Joh, Neirynck, Johan, Knops, Johannes, Loehr, John, von Oppen, Jonathan, Þorláksdóttir, Jónína Sigríður, Löffler, Jörg, Cardoso-Mohedano, José-Gilberto, Benito-Alonso, José-Luis, Torezan, Jose Marcelo, Morina, Joseph C., Jiménez, Juan J., Quinde, Juan Dario, Alatalo, Juha, Seeber, Julia, Stadler, Jutta, Kriiska, Kaie, Coulibaly, Kalifa, Fukuzawa, Karibu, Szlavecz, Katalin, Gerhátová, Katarína, Lajtha, Kate, Käppeler, Kathrin, Jennings, Katie A., Tielbörger, Katja, Hoshizaki, Kazuhiko, Green, Ken, Yé, Lambiénou, Pazianoto, Laryssa Helena Ribeiro, Dienstbach, Laura, Williams, Laura, Yahdjian, Laura, Brigham, Laurel M., van den Brink, Liesbeth, Rustad, Lindsey, Zhang, Lipeng, Morillas, Lourdes, Xiankai, Lu, Carneiro, Luciana Silva, Di Martino, Luciano, Villar, Luis, Bader, Maaike Y., Morley, Madison, Lebouvier, Marc, Tomaselli, Marcello, Sternberg, Marcelo, Schaub, Marcus, Santos-Reis, Margarida, Glushkova, Maria, Torres, María Guadalupe Almazán, Giroux, Marie-Andrée, de Graaff, Marie-Anne, Pons, Marie-Noëlle, Bauters, Marijn, Mazón, Marina, Frenzel, Mark, Didion, Markus, Wagner, Markus, Hamid, Maroof, Lopes, Marta L., Apple, Martha, Schädler, Martin, Weih, Martin, Gualmini, Matteo, Vadeboncoeur, Matthew A., Bierbaumer, Michael, Danger, Michael, Liddell, Michael, Mirtl, Michael, Scherer-Lorenzen, Michael, Růžek, Michal, Carbognani, Michele, Di Musciano, Michele, Matsushita, Michinari, Zhiyanski, Miglena, Pușcaș, Mihai, Barna, Milan, Ataka, Mioko, Jiangming, Mo, Alsafran, Mohammed, Carnol, Monique, Barsoum, Nadia, Tokuchi, Naoko, Eisenhauer, Nico, Lecomte, Nicolas, Filippova, Nina, Hölzel, Norbert, Ferlian, Olga, Romero, Oscar, Pinto, Osvaldo B., Peri, Pablo, Weber, Paige, Vittoz, Pascal, Turtureanu, Pavel Dan, Fleischer, Peter, Macreadie, Peter, Haase, Peter, Reich, Peter, Petřík, Petr, Choler, Philippe, Marmonier, Pierre, Muriel, Priscilla, Ponette, Quentin, Guariento, Rafael Dettogni, Canessa, Rafaella, Kiese, Ralf, Hewitt, Rebecca, Rønn, Regin, Adrian, Rita, Kanka, Róbert, Weigel, Robert, Gatti, Roberto Cazzolla, Martins, Rodrigo Lemes, Georges, Romain, Meneses, Rosa Isela, Gavilán, Rosario G., Dasgupta, Sabyasachi, Wittlinger, Sally, Puijalon, Sara, Freda, Sarah, Suzuki, Satoshi, Charles, Sean, Gogo, Sébastien, Drollinger, Simon, Mereu, Simone, Wipf, Sonja, Trevathan-Tackett, Stacey, Löfgren, Stefan, Stoll, Stefan, Trogisch, Stefan, Hoeber, Stefanie, Seitz, Steffen, Glatzel, Stephan, Milton, Sue J., Dousset, Sylvie, Mori, Taiki, Sato, Takanori, Ise, Takeshi, Hishi, Takuo, Kenta, Tanaka, Nakaji, Tatsuro, Michelan, Thaisa Sala, Camboulive, Thierry, Mozdzer, Thomas J., Scholten, Thomas, Spiegelberger, Thomas, Zechmeister, Thomas, Kleinebecker, Till, Hiura, Tsutom, Enoki, Tsutomu, Ursu, Tudor-Mihai, di Cella, Umberto Morra, Hamer, Ute, Klaus, Valentin H., Rêgo, Vanessa Mendes, Di Cecco, Valter, Busch, Verena, Fontana, Veronika, Piscová, Veronika, Carbonell, Victoria, Ochoa, Victoria, Bretagnolle, Vincent, Maire, Vincent, Farjalla, Vinicius, Zhou, Wenjun, Luo, Wentao, McDowell, William H., Hu, Yalin, Utsumi, Yasuhiro, Kominami, Yuji, Zaika, Yulia, Rozhkov, Yury, Kotroczó, Zsolt, and Tóth, Zsolt

Abstract

Through litter decomposition enormous amounts of carbon is emitted to the atmosphere. Numerous large-scale decomposition experiments have been conducted focusing on this fundamental soil process in order to understand the controls on the terrestrial carbon transfer to the atmosphere. However, previous studies were mostly based on site-specific litter and methodologies, adding major uncertainty to syntheses, comparisons and meta-analyses across different experiments and sites. In the TeaComposition initiative, the potential litter decomposition is investigated by using standardized substrates (Rooibos and Green tea) for comparison of litter mass loss at 336 sites (ranging from −9 to +26 °C MAT and from 60 to 3113 mm MAP) across different ecosystems. In this study we tested the effect of climate (temperature and moisture), litter type and land-use on early stage decomposition (3 months) across nine biomes. We show that litter quality was the predominant controlling factor in early stage litter decomposition, which explained about 65% of the variability in litter decomposition at a global scale. The effect of climate, on the other hand, was not litter specific and explained <0.5% of the variation for Green tea and 5% for Rooibos tea, and was of significance only under unfavorable decomposition conditions (i.e. xeric versus mesic environments). When the data were aggregated at the biome scale, climate played a significant role on decomposition of both litter types (explaining 64% of the variation for Green tea and 72% for Rooibos tea). No significant effect of land-use on early stage litter decomposition was noted within the temperate biome. Our results indicate that multiple drivers are affecting early stage litter mass loss with litter quality being dominant. In order to be able to quantify the relative importance of the different drivers over time, long-term studies combined with experimental trials are needed.

Published
2018

20. The Passy-2015 field experiment: atmospheric dynamics and air quality in the Arve River Valley

Author

Paci, Alexandre, Staquet, Chantal, Allard, Julie, Barral, Hélène, Canut, Guylaine, Cohard, Jean-Martial, Jaffrezo, Jean-Luc, Martinet, Pauline, Sabatier, Tiphaine, Troude, Florence, Arduini, Gabriele, Burnet, Fréderic, Brun, Christophe, Chemel, Charles, Dabas, Alain, Donier, Jean-Marie, Garrouste, Olivier, Guillot, Rémi, Largeron, Yann, Legain, Dominique, Maurel, William, Tzanos, Diane, Barrau, Sébastien, Barret, Manuel, Barrié, Joël, Belleudy, Anne, Bouhours, Gilles, Bourrianne, Thierry, Chevrier, Florie, Douffet, Thierry, Etcheberry, Jean-Michel, Gustave, Laurent, Mazoyer, Marie, Mercier, Stéphane, Moulin, Eric, Pellan, Yann, Piguet, Bruno, Rodier, Quentin, Zin, Isabella, Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut des Géosciences de l’Environnement (IGE), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut de Recherche pour le Développement (IRD)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire d'aérologie (LAERO), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Centre national de recherches météorologiques (CNRM), Association agréée Surveillance Qualité de l'air (AASQA), Atmo Nord Pas-de-Calais-Air Rhône-Alpes, University of Hertfordshire [Hatfield] (UH), Thales Alenia Space [Cannes], Thales Alenia Space, Air Rhône-Alpes, Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Thales Alenia Space [Toulouse] (TAS), and THALES [France]

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Atmospheric pollution, Vallée de l’Arve, Arve River Valley, [SPI.FLUID]Engineering Sciences [physics]/Reactive fluid environment, [SDE.MCG]Environmental Sciences/Global Changes, Passy-2015, Atmospheric boundary layer, Campagne de mesure, Field experiment, Couche limite atmosphérique, Wintertime stable conditions, Pollution atmosphérique, Conditions stables hivernales
Abstract

International audience; Wintertime anticyclonic conditions, associated with clear sky and cold nights, trigger the formation of persistent layers of stable air over the ground. In an urban area, these persistent layers lead to poor air quality, especially when the terrain is mountainous. This is particularly the case in the Arve River Valley near the city of Passy, located 20 km downstream of Chamonix-Mont-Blanc, where air quality stands among the poorest ones in France.Beyond the monitoring of air quality, as performed by the Auvergne-Rhône-Alpes air quality agency or within the scientific project DECOMBIO led by the Institute for Geosciences and the Environment (IGE), knowledge of the atmospheric dynamics at the valley scale should be gained to understand how pollutants are dispersed. This is the motivation of the Passy project, which started in 2014. It relies on the Passy-2015 field experiment, whereof presentation, along with the discussion of a few results, is the purpose of the present paper. The objective of this field experiment is to document the atmospheric dynamics in the Arve River Valley during wintertime pollution episodes.The work conducted during the Passy project and the analysis of the Passy-2015 field experiment will benefit from a several-year long collaboration among the different partners. The knowledge thus gained will contribute to refine weather forecast and air quality prediction in the Arve River Valley and, more generally, in mountain urban areas under stable conditions. From an operational perspective, our goal is to improve our ability to forecast critical events such as low temperatures, ice and fog formation, pollution events or locations subject to high pollutant concentration.; Les conditions anticycloniques hivernales (ciel clair, nuits froides) conduisent à la formation de couches stables persistantes qui favorisent les épisodes de pollution, particulièrement en terrain montagneux. La vallée de l’Arve est très sensible à ce phénomène, en particulier près de la ville de Passy (Haute-Savoie), située à 20 kilomètres en aval de Chamonix-Mont-Blanc, où la qualité de l’air est l’une des moins bonnes de France.Au-delà du suivi de la qualité de l’air, tel que réalisé par Atmo Auvergne-Rhône-Alpes ou par le projet DECOMBIO piloté par l’Institut des Géosciences et de l’Environnement (IGE), il est primordial d’améliorer la connaissance de la dynamique atmosphérique à l’échelle de la vallée en conditions stables pour mieux comprendre comment, couplée au cycle et à la géographie des émissions, elle pilote la dispersion des polluants. C’est la motivation du projet Passy, initié en 2014. Ce projet s’appuie sur les observations de la campagne Passy-2015, présentées dans cet article avec quelques premiers résultats. L’objectif général de cette campagne est de documenter la dynamique atmosphérique au sein de la vallée de l’Arve lors des épisodes de pollution hivernale.Les travaux menés dans le cadre du projet et de l’analyse des données de la campagne s’inscrivent au sein d’une collaboration sur plusieurs années entre les différents partenaires. Ils contribueront à affiner la prévision du temps et de la qualité de l’air dans ce type de vallée, et plus généralement en conditions stables. Il s’agit en particulier d’améliorer la capacité à prévoir des phénomènes critiques, comme les températures minimales, le verglas, le brouillard, les évènements de pollution ou encore les zones de pollution intense.

Published
2016

21. Early stage litter decomposition across biomes

Author

Djukic, Ika, primary, Kepfer-Rojas, Sebastian, additional, Schmidt, Inger Kappel, additional, Larsen, Klaus Steenberg, additional, Beier, Claus, additional, Berg, Björn, additional, Verheyen, Kris, additional, Caliman, Adriano, additional, Paquette, Alain, additional, Gutiérrez-Girón, Alba, additional, Humber, Alberto, additional, Valdecantos, Alejandro, additional, Petraglia, Alessandro, additional, Alexander, Heather, additional, Augustaitis, Algirdas, additional, Saillard, Amélie, additional, Fernández, Ana Carolina Ruiz, additional, Sousa, Ana I., additional, Lillebø, Ana I., additional, da Rocha Gripp, Anderson, additional, Francez, André-Jean, additional, Fischer, Andrea, additional, Bohner, Andreas, additional, Malyshev, Andrey, additional, Andrić, Andrijana, additional, Smith, Andy, additional, Stanisci, Angela, additional, Seres, Anikó, additional, Schmidt, Anja, additional, Avila, Anna, additional, Probst, Anne, additional, Ouin, Annie, additional, Khuroo, Anzar A., additional, Verstraeten, Arne, additional, Palabral-Aguilera, Arely N., additional, Stefanski, Artur, additional, Gaxiola, Aurora, additional, Muys, Bart, additional, Bosman, Bernard, additional, Ahrends, Bernd, additional, Parker, Bill, additional, Sattler, Birgit, additional, Yang, Bo, additional, Juráni, Bohdan, additional, Erschbamer, Brigitta, additional, Ortiz, Carmen Eugenia Rodriguez, additional, Christiansen, Casper T., additional, Carol Adair, E., additional, Meredieu, Céline, additional, Mony, Cendrine, additional, Nock, Charles A., additional, Chen, Chi-Ling, additional, Wang, Chiao-Ping, additional, Baum, Christel, additional, Rixen, Christian, additional, Delire, Christine, additional, Piscart, Christophe, additional, Andrews, Christopher, additional, Rebmann, Corinna, additional, Branquinho, Cristina, additional, Polyanskaya, Dana, additional, Delgado, David Fuentes, additional, Wundram, Dirk, additional, Radeideh, Diyaa, additional, Ordóñez-Regil, Eduardo, additional, Crawford, Edward, additional, Preda, Elena, additional, Tropina, Elena, additional, Groner, Elli, additional, Lucot, Eric, additional, Hornung, Erzsébet, additional, Gacia, Esperança, additional, Lévesque, Esther, additional, Benedito, Evanilde, additional, Davydov, Evgeny A., additional, Ampoorter, Evy, additional, Bolzan, Fabio Padilha, additional, Varela, Felipe, additional, Kristöfel, Ferdinand, additional, Maestre, Fernando T., additional, Maunoury-Danger, Florence, additional, Hofhansl, Florian, additional, Kitz, Florian, additional, Sutter, Flurin, additional, Cuesta, Francisco, additional, de Almeida Lobo, Francisco, additional, de Souza, Franco Leandro, additional, Berninger, Frank, additional, Zehetner, Franz, additional, Wohlfahrt, Georg, additional, Vourlitis, George, additional, Carreño-Rocabado, Geovana, additional, Arena, Gina, additional, Pinha, Gisele Daiane, additional, González, Grizelle, additional, Canut, Guylaine, additional, Lee, Hanna, additional, Verbeeck, Hans, additional, Auge, Harald, additional, Pauli, Harald, additional, Nacro, Hassan Bismarck, additional, Bahamonde, Héctor A., additional, Feldhaar, Heike, additional, Jäger, Heinke, additional, Serrano, Helena C., additional, Verheyden, Hélène, additional, Bruelheide, Helge, additional, Meesenburg, Henning, additional, Jungkunst, Hermann, additional, Jactel, Hervé, additional, Shibata, Hideaki, additional, Kurokawa, Hiroko, additional, Rosas, Hugo López, additional, Rojas Villalobos, Hugo L., additional, Yesilonis, Ian, additional, Melece, Inara, additional, Van Halder, Inge, additional, Quirós, Inmaculada García, additional, Makelele, Isaac, additional, Senou, Issaka, additional, Fekete, István, additional, Mihal, Ivan, additional, Ostonen, Ivika, additional, Borovská, Jana, additional, Roales, Javier, additional, Shoqeir, Jawad, additional, Lata, Jean-Christophe, additional, Theurillat, Jean-Paul, additional, Probst, Jean-Luc, additional, Zimmerman, Jess, additional, Vijayanathan, Jeyanny, additional, Tang, Jianwu, additional, Thompson, Jill, additional, Doležal, Jiří, additional, Sanchez-Cabeza, Joan-Albert, additional, Merlet, Joël, additional, Henschel, Joh, additional, Neirynck, Johan, additional, Knops, Johannes, additional, Loehr, John, additional, von Oppen, Jonathan, additional, Þorláksdóttir, Jónína Sigríður, additional, Löffler, Jörg, additional, Cardoso-Mohedano, José-Gilberto, additional, Benito-Alonso, José-Luis, additional, Torezan, Jose Marcelo, additional, Morina, Joseph C., additional, Jiménez, Juan J., additional, Quinde, Juan Dario, additional, Alatalo, Juha, additional, Seeber, Julia, additional, Stadler, Jutta, additional, Kriiska, Kaie, additional, Coulibaly, Kalifa, additional, Fukuzawa, Karibu, additional, Szlavecz, Katalin, additional, Gerhátová, Katarína, additional, Lajtha, Kate, additional, Käppeler, Kathrin, additional, Jennings, Katie A., additional, Tielbörger, Katja, additional, Hoshizaki, Kazuhiko, additional, Green, Ken, additional, Yé, Lambiénou, additional, Pazianoto, Laryssa Helena Ribeiro, additional, Dienstbach, Laura, additional, Williams, Laura, additional, Yahdjian, Laura, additional, Brigham, Laurel M., additional, van den Brink, Liesbeth, additional, Rustad, Lindsey, additional, Zhang, Lipeng, additional, Morillas, Lourdes, additional, Xiankai, Lu, additional, Carneiro, Luciana Silva, additional, Di Martino, Luciano, additional, Villar, Luis, additional, Bader, Maaike Y., additional, Morley, Madison, additional, Lebouvier, Marc, additional, Tomaselli, Marcello, additional, Sternberg, Marcelo, additional, Schaub, Marcus, additional, Santos-Reis, Margarida, additional, Glushkova, Maria, additional, Torres, María Guadalupe Almazán, additional, Giroux, Marie-Andrée, additional, de Graaff, Marie-Anne, additional, Pons, Marie-Noëlle, additional, Bauters, Marijn, additional, Mazón, Marina, additional, Frenzel, Mark, additional, Didion, Markus, additional, Wagner, Markus, additional, Hamid, Maroof, additional, Lopes, Marta L., additional, Apple, Martha, additional, Schädler, Martin, additional, Weih, Martin, additional, Gualmini, Matteo, additional, Vadeboncoeur, Matthew A., additional, Bierbaumer, Michael, additional, Danger, Michael, additional, Liddell, Michael, additional, Mirtl, Michael, additional, Scherer-Lorenzen, Michael, additional, Růžek, Michal, additional, Carbognani, Michele, additional, Di Musciano, Michele, additional, Matsushita, Michinari, additional, Zhiyanski, Miglena, additional, Pușcaș, Mihai, additional, Barna, Milan, additional, Ataka, Mioko, additional, Jiangming, Mo, additional, Alsafran, Mohammed, additional, Carnol, Monique, additional, Barsoum, Nadia, additional, Tokuchi, Naoko, additional, Eisenhauer, Nico, additional, Lecomte, Nicolas, additional, Filippova, Nina, additional, Hölzel, Norbert, additional, Ferlian, Olga, additional, Romero, Oscar, additional, Pinto, Osvaldo B., additional, Peri, Pablo, additional, Weber, Paige, additional, Vittoz, Pascal, additional, Turtureanu, Pavel Dan, additional, Fleischer, Peter, additional, Macreadie, Peter, additional, Haase, Peter, additional, Reich, Peter, additional, Petřík, Petr, additional, Choler, Philippe, additional, Marmonier, Pierre, additional, Muriel, Priscilla, additional, Ponette, Quentin, additional, Guariento, Rafael Dettogni, additional, Canessa, Rafaella, additional, Kiese, Ralf, additional, Hewitt, Rebecca, additional, Rønn, Regin, additional, Adrian, Rita, additional, Kanka, Róbert, additional, Weigel, Robert, additional, Gatti, Roberto Cazzolla, additional, Martins, Rodrigo Lemes, additional, Georges, Romain, additional, Meneses, Rosa Isela, additional, Gavilán, Rosario G., additional, Dasgupta, Sabyasachi, additional, Wittlinger, Sally, additional, Puijalon, Sara, additional, Freda, Sarah, additional, Suzuki, Satoshi, additional, Charles, Sean, additional, Gogo, Sébastien, additional, Drollinger, Simon, additional, Mereu, Simone, additional, Wipf, Sonja, additional, Trevathan-Tackett, Stacey, additional, Löfgren, Stefan, additional, Stoll, Stefan, additional, Trogisch, Stefan, additional, Hoeber, Stefanie, additional, Seitz, Steffen, additional, Glatzel, Stephan, additional, Milton, Sue J., additional, Dousset, Sylvie, additional, Mori, Taiki, additional, Sato, Takanori, additional, Ise, Takeshi, additional, Hishi, Takuo, additional, Kenta, Tanaka, additional, Nakaji, Tatsuro, additional, Michelan, Thaisa Sala, additional, Camboulive, Thierry, additional, Mozdzer, Thomas J., additional, Scholten, Thomas, additional, Spiegelberger, Thomas, additional, Zechmeister, Thomas, additional, Kleinebecker, Till, additional, Hiura, Tsutom, additional, Enoki, Tsutomu, additional, Ursu, Tudor-Mihai, additional, di Cella, Umberto Morra, additional, Hamer, Ute, additional, Klaus, Valentin H., additional, Rêgo, Vanessa Mendes, additional, Di Cecco, Valter, additional, Busch, Verena, additional, Fontana, Veronika, additional, Piscová, Veronika, additional, Carbonell, Victoria, additional, Ochoa, Victoria, additional, Bretagnolle, Vincent, additional, Maire, Vincent, additional, Farjalla, Vinicius, additional, Zhou, Wenjun, additional, Luo, Wentao, additional, McDowell, William H., additional, Hu, Yalin, additional, Utsumi, Yasuhiro, additional, Kominami, Yuji, additional, Zaika, Yulia, additional, Rozhkov, Yury, additional, Kotroczó, Zsolt, additional, and Tóth, Zsolt, additional

Published
2018
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23. The Turbulent Structure of the Arctic Summer Boundary Layer During The Arctic Summer Cloud-Ocean Study

Author

Brooks, Ian M., Tjernström, Michael, Persson, P. Ola G., Shupe, Matthew D., Atkinson, Rebecca A., Canut, Guylaine, Birch, Cathryn E., Mauritsen, Thorsten, Sedlar, Joseph, Brooks, Barbara J., Brooks, Ian M., Tjernström, Michael, Persson, P. Ola G., Shupe, Matthew D., Atkinson, Rebecca A., Canut, Guylaine, Birch, Cathryn E., Mauritsen, Thorsten, Sedlar, Joseph, and Brooks, Barbara J.

Abstract

The mostly ice covered Arctic Ocean is dominated by low-level liquid-or mixed-phase clouds. Turbulence within stratocumulus is primarily driven by cloud top cooling that induces convective instability. Using a suite of in situ and remote sensing instruments we characterize turbulent mixing in Arctic stratocumulus, and for the first time we estimate profiles of the gradient Richardson number at relatively high resolution in both time (10 min) and altitude (10 m). It is found that the mixing occurs both within the cloud, as expected, and by wind shear instability near the surface. About 75% of the time these two layers are separated by a stably stratified inversion at 100-200 m altitude. Exceptions are associated with low cloud bases that allow the cloud-driven turbulence to reach the surface. The results imply that turbulent coupling between the surface and the cloud is sporadic or intermittent. Plain Language Summary: The lower atmosphere over the summertime Arctic Ocean often consists of two well-mixed layers-a surface mixed layer and a cloud mixed layer-that are separated by a weak decoupling layer at about 100 to 300 m above the surface. In these cases, the cloud cannot interact directly with the surface. Large-scale forecast and climate models consistently fail to reproduce this observed structure and may thus fail to correctly reproduce the cloud properties and the amount of energy absorbed by or emitted from the surface as solar and infrared radiation. This contributes to errors in reproducing changes in sea ice concentration over time. Here we use measurements made in the central Arctic to study the processes controlling whether or not the cloud is coupled to the surface. The effect of wind at the surface is found not to be a controlling factor. The depth of the cloud mixed layer is critical, but the multiple processes influencing it cannot be separated using the data available here. However, cooling at cloud top by infrared radiation is key, as is the extens

Published
2017
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28. Boundary-layer turbulent processes and mesoscale variability represented by Numerical Weather Prediction models during the BLLAST campaign

Author

Couvreux, Fleur, Bazile, Eric, Canut, Guylaine, Lothon, Marie, Lohou, Fabienne, Guichard, Françoise, Nilsson, Erik, Couvreux, Fleur, Bazile, Eric, Canut, Guylaine, Lothon, Marie, Lohou, Fabienne, Guichard, Françoise, and Nilsson, Erik

Abstract

This study evaluates the ability of three operational models, AROME, ARPEGE and ECMWF, to predict the boundary-layer turbulent processes and mesoscale variability observed during the Boundary Layer Late-Afternoon and Sunset Turbulence (BLLAST) field campaign. AROME is a 2.5 km limited area non-hydrostatic model operated over France, ARPEGE a global model with a 10 km grid-size over France and ECMWF a global model with a 16 km grid-size. We analyze the representation of the vertical profiles of temperature and humidity and the time evolution of near surface atmospheric variables as well as the radiative and turbulent fluxes for a total of 12 24h-long Intensive Observing Periods. Special attention is paid to the evolution of the turbulent kinetic energy that was sampled by a combination of independent instruments. For the first time, this variable, which is a central variable in the turbulence scheme used in AROME and ARPEGE, is evaluated with observations.

Published
2016
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31. A study of local turbulence and anisotropy during the afternoon and evening transition with an unmanned aerial system and mesoscale simulation

Author

Lampert, Astrid, primary, Pätzold, Falk, additional, Jiménez, Maria Antonia, additional, Lobitz, Lennart, additional, Martin, Sabrina, additional, Lohmann, Gerald, additional, Canut, Guylaine, additional, Legain, Dominique, additional, Bange, Jens, additional, Martínez-Villagrasa, Dani, additional, and Cuxart, Joan, additional

Published
2016
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36. La campagne Passy-2015 : dynamique atmosphérique et qualité de l’air dans la vallée de l’Arve

Author

PACI, Alexandre, primary, STAQUET, Chantal, additional, ALLARD, Julie, additional, BARRAL, Hélène, additional, CANUT, Guylaine, additional, COHARD, Jean-Martial, additional, JAFFREZO, Jean-Luc, additional, MARTINET, Pauline, additional, SABATIER, Tiphaine, additional, TROUDE, Florence, additional, ARDUINI, Gabriele, additional, BURNET, Frédéric, additional, BRUN, Christophe, additional, CHEMEL, Charles, additional, DABAS, Alain, additional, DONIER, Jean-Marie, additional, GARROUSTE, Olivier, additional, GUILLOT, Rémi, additional, LARGERON, Yann, additional, LEGAIN, Dominique, additional, MAUREL, William, additional, TZANOS, Diane, additional, BARRAU, Sébastien, additional, BARRET, Manuel, additional, BARRIE, Joël, additional, BELLEUDY, Anne, additional, BOUHOURS, Gilles, additional, BOURRIANNE, Thierry, additional, CHEVRIER, Florie, additional, DOUFFET, Thierry, additional, ETCHEBERRY, Jean-Michel, additional, GUSTAVE, Laurent, additional, MAZOYER, Marie, additional, MERCIER, Stéphane, additional, MOULIN, Éric, additional, PELLAN, Yann, additional, PIGUET, Bruno, additional, RODIER, Quentin, additional, and ZIN, Isabella, additional

Published
2016
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37. TKE decay and budget in the afternoon transition

Author

Nilsson, Erik, Lothon, Marie, Lohou, Fabienne, Darbieu, Clara, Pardyjak, Eric, Couvreux, Fleur, Canut, Guylaine, Mahrt, Larry, Nilsson, Erik, Lothon, Marie, Lohou, Fabienne, Darbieu, Clara, Pardyjak, Eric, Couvreux, Fleur, Canut, Guylaine, and Mahrt, Larry

Published
2015

38. Initiation of daytime local convection in a semi-arid region analysed with high-resolution simulations and AMMA observations

Author

Couvreux, Fleur, Rio, Catherine, Guichard, Francoise, Lothon, Marie, Canut, Guylaine, Bouniol, Dominique, Gounou, Amanda, Météo France, Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Laboratoire d'aérologie (LAERO), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Météo-France Direction Interrégionale Sud-Est (DIRSE), Météo-France, Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]
Abstract

International audience; A modelling case study designed from observations from the African Monsoon Multidisciplinary Analysis (AMMA) is presented and discussed. It aims at investigating the issue of initiation of convection in a semi-arid environment. This case corresponds to the development of local daytime convection mainly controlled by boundary layer characteristics rather than by atmospheric synoptic scales. A high-resolution three-dimensional simulation is presented and extensively evaluated against the numerous observations available for 10 July 2006 from the AMMA campaign. The simulation, run over a domain of 100 × 100 km, is able to represent main boundary layer structures and processes leading to deep convection initiation as well as the formation of density currents. Sensitivity tests point to the key role of the sensible heat flux, the humidity of low to mid levels, the lapse rate at low levels and of a mesoscale ascent to initiate deep convection in those semi-arid conditions, while evaporation of precipitation is shown to play a minor role. This study thus provides a case to investigate the ability of parametrizations to handle the initiation of convection in a semi-arid environment.

Published
2012

39. Intéraction Mousson/Harmattan, échanges de petite échelle

Author

Canut, Guylaine, Laboratoire d'aérologie (LAERO), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Paul Sabatier - Toulouse III, Marie LOTHON & Frédérique SAID, Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées

Subjects
mousson, [PHYS.PHYS]Physics [physics]/Physics [physics], entrainment, turbulence, intrusions sèches, Atmospheric Boundary Layer, Sahelian Boundary Layer, entraînement, dry intrusions, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, LES, monsoon, AMMA, Couche Limite Atmosphérique, Couche Limite Sahélienne
Abstract

Entrainment of dry air from the Harmattan flow inside the moist monsoon flow is a turbulent process. This process is analysed in the context of the AMMA (African Monsoon Multidisciplinary Analysis) campaign experiment, which aimed at better understanding and forecasting the African Monsoon. The atmospheric measurements made by the ATR-42 research aircraft, and large eddy simulations enable us in a complementary way to study the mean and turbulent vertical structure of the sahelian boundary layer, to describe the dry intrusions and their contributions in the turbulent transferts, to quantify the entrainment process, to test the existing parametrizations and to link the entrainment process with the conditions, and with the characteristics of the boundary layer and its interfaces, in particular the windshear between monsoon & Harmattan.; C'est a l'échelle de la turbulence que se produit l'entraînement d'air sec du flux d'Harmattan a l'intérieur du flux humide de Mousson. Ce processus de petite échelle est analysé dans le cadre du programme AMMA (Analyse Multidisciplinaires de la Mousson Africaine) qui vise a mieux renseigner et prévoir la mousson de l'Afrique de l'ouest. Les mesures atmosphériques réalisées par l'avion de recherche français ATR-42 et la modélisation des grands tourbillons (LES) sont complémentaires et permettent de documenter la structure verticale, moyenne et turbulente de la couche limite Sahélienne, de d'écrire les intrusions d'air sec et leur contribution dans les transferts turbulents, de quantifier le processus d'entraînement, de tester les paramétrisations existantes et de les relier aux conditions de grande échelle, et aux caractéristiques de la couche limite et de ses interfaces, notamment du cisaillement de vent Mousson/Harmattan.

Published
2010

40. Mousson/Harmattan interaction, exchanges by small scale

Author

Canut, Guylaine, Laboratoire d'aérologie (LAERO), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Université Paul Sabatier - Toulouse III, and Marie LOTHON & Frédérique SAID

Subjects
mousson, [PHYS.PHYS]Physics [physics]/Physics [physics], entrainment, turbulence, intrusions sèches, Atmospheric Boundary Layer, Sahelian Boundary Layer, entraînement, dry intrusions, [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology, LES, monsoon, AMMA, Couche Limite Atmosphérique, Couche Limite Sahélienne
Abstract

Entrainment of dry air from the Harmattan flow inside the moist monsoon flow is a turbulent process. This process is analysed in the context of the AMMA (African Monsoon Multidisciplinary Analysis) campaign experiment, which aimed at better understanding and forecasting the African Monsoon. The atmospheric measurements made by the ATR-42 research aircraft, and large eddy simulations enable us in a complementary way to study the mean and turbulent vertical structure of the sahelian boundary layer, to describe the dry intrusions and their contributions in the turbulent transferts, to quantify the entrainment process, to test the existing parametrizations and to link the entrainment process with the conditions, and with the characteristics of the boundary layer and its interfaces, in particular the windshear between monsoon & Harmattan.; C'est a l'échelle de la turbulence que se produit l'entraînement d'air sec du flux d'Harmattan a l'intérieur du flux humide de Mousson. Ce processus de petite échelle est analysé dans le cadre du programme AMMA (Analyse Multidisciplinaires de la Mousson Africaine) qui vise a mieux renseigner et prévoir la mousson de l'Afrique de l'ouest. Les mesures atmosphériques réalisées par l'avion de recherche français ATR-42 et la modélisation des grands tourbillons (LES) sont complémentaires et permettent de documenter la structure verticale, moyenne et turbulente de la couche limite Sahélienne, de d'écrire les intrusions d'air sec et leur contribution dans les transferts turbulents, de quantifier le processus d'entraînement, de tester les paramétrisations existantes et de les relier aux conditions de grande échelle, et aux caractéristiques de la couche limite et de ses interfaces, notamment du cisaillement de vent Mousson/Harmattan.

Published
2010

41. Seasonal evolution of boundary-layer turbulence measured by aircraft during the AMMA 2006 Special Observation Period

Author

Saïd, Frédérique, Canut, Guylaine, Durand, Philippe, Lohou, Fabienne, Lothon, Marie, Laboratoire d'aérologie (LAERO), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées

Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], atmospheric turbulent fluxes, entrainment, monsoon, Harmattan, [SDU.STU.ME]Sciences of the Universe [physics]/Earth Sciences/Meteorology
Abstract

International audience; During the African Monsoon Multidisciplinary Analysis (AMMA) field campaign, the ATR research aircraft made observations of fluxes and thermodynamics during three 15-day periods, which allowed the seasonal evolution of the atmospheric boundary-layer (ABL) characteristics to be monitored before and after the monsoon onset. As expected, temperature and humidity showed a contrast between dry warm conditions and moister cooler conditions from one period to the other. Most of the time, the wind blew from the west (northwesterly to southwesterly) in the ABL and from the east in the free troposphere. Following rainfall events occuring in July and August, surface sensible heat flux decreased and evaporation increased while the momentum flux remained large in the entire boundary layer, whatever the period. The aim of this paper is to characterize turbulence in terms of fluxes and length-scales for ABLs that exhibit particular characteristics relative to (i) entrainment at the top, (ii) wind rotation at the interface between the monsoon and the Saharan air layer and (iii) seasonal variability. In spite of the poorer accuracy of the turbulent flux estimations at the top of the ABL, the flux profiles were observed to increase or decrease linearly with altitude which enabled accurate estimates of entrainment flux ratios. It was found that the moisture flux distribution in the ABL was governed by top-down processes during the driest period and a mixture of top-down and bottom-up processes during the monsoon period. Significant differences in turbulence length-scales were also highlighted.

Published
2010

42. Observation of entrainment at the interface between monsoon flow and the Saharan Air Layer

Author

Canut, Guylaine, Lothon, Marie, Saïd, Frédérique, Lohou, Fabienne, Laboratoire d'aérologie (LAERO), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]
Abstract

International audience; During the AMMA experiment, the French ATR aircraft flew in the lower troposphere in south Niger, with instruments that allow fast measurement of wind, temperature and humidity. Stacked legs flown between early June and mid-August into the moist southwesterly monsoon flow and the dry northeasterly flow of the Saharan Air Layer (SAL) above, enable us to study the interaction between the two flows at the turbulence scale and the role of the planetary boundary layer (PBL) in the transfers between them. We describe the fluctuations observed at the top of the PBL and their evolution during the season. Dry tongues approximately 600 m wide and a few kilometres apart, intruding from the overlying SAL down into the PBL, are characteristic of the Sahelian region at that time of year. They are fully part of the entrainment process at the PBL top and responsible for large moisture fluxes in the upper PBL. They also skew the water vapour distribution which in turn impacts the water vapour scales. We evaluate the impact of the entrainment by use of a conditional analysis on combined fluctuations. The dry tongues play the largest role down to two thirds of the PBL depth. We find larger entrainment during early monsoon than during its active phase, and a large variability of the ratio of entrainment buoyancy flux over surface flux.

Published
2010

43. Studying the Boundary Layer Late Afternoon and Sunset Turbulence (BLLAST)

Author

Vilà-Guerau de Arellano, Jordi, Pino González, David, Pardyjak, Erick, Mahrt, Larry, Lohou, Fabienne, Jonker, Harm J. J., Gioli, Beniamino, Gibert, Fabien, Durand, Pierre, Lothon, Marie, Lenschow, Donald, Angevine, Wayne, Bange, Jens, Beare, Robert, Canut, Guylaine, Couvreux, Fleur, Delbarre, Hervé, Universitat Politècnica de Catalunya. Departament de Física Aplicada, and Universitat Politècnica de Catalunya. DF - Dinàmica No Lineal de Fluids

Subjects
Física [Àrees temàtiques de la UPC], Capa límit (Meteorologia), Boundary layer (Meteorology)
Abstract

At the end of the afternoon, when the surface heat fluxes start to sharply decrease, the CBL turns from a convective well-mixed layer to an intermittently turbulent residual layer overlying a stably-stratified boundary layer. This transition raises several observational and modelling issues. Even the definition of the boundary layer during this period is fuzzy, since there is no consensus on what criteria to use and no simple scaling laws to apply. Yet it plays an important role in such diverse atmospheric phenomena as transport and diffusion of trace constituents or wind energy production. This phase of the diurnal cycle remains largely unexplored, partly due to the difficulty of measuring weak and intermittent turbulence, anisotropy, horizontal heterogeneity, and rapid time changes. The Boundary Layer Late Afternoon and Sunset Turbulence (BLLAST) project is gathering about thirty research scientists from the European Union and the United States to work on this issue. A field campaign (BLLAST-FE) is planned for spring or summer 2011 in Europe. BLLAST will utilize these observations, as well as previous datasets, large-eddy and direct numerical simulations, and mesoscale modelling to better understand the processes, suggest new parameterisations, and evaluate forecast models during this transitional period. We will present the issues raised by the late afternoon transition and our strategy to study it.

Published
2010

44. The entrainment process between the Monsoon flow and the Saharan Air Layer in the West African Monsoon system

Author

Canut, Guylaine, Couvreux, Fleur, Lothon, Marie, Pino González, David, Saïd, Frédérique, Universitat Politècnica de Catalunya. Departament de Física Aplicada, and Universitat Politècnica de Catalunya. DF - Dinàmica No Lineal de Fluids

Subjects
Capa límit (Dinàmica de fluids), Física [Àrees temàtiques de la UPC], Boundary layer (Meteorology) -- Sahara, education, Eddies
Published
2010

45. Role of the planetary boundary layer in the interaction between monsoon flux and Harmattan flux in the West African Monsoon system

Author

Canut, Guylaine, Lohou, Fabienne, Saïd, Frédérique, Lothon, Marie, Durand, Pierre, Groupe d'étude de l'atmosphère météorologique (CNRM-GAME), Institut national des sciences de l'Univers (INSU - CNRS)-Météo France-Centre National de la Recherche Scientifique (CNRS), Laboratoire d'aérologie (LAERO), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées

Subjects
[PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]
Published
2007

46. HyMeX-SOP2.

Author

Estournel, Claude, Testor, Pierre, Taupier-Letage, Isabelle, Bouin, Marie-Noelle, Coppola, Laurent, Durand, Pierre, Conan, Pascal, Bosse, Anthony, Brilouet, Pierre-Etienne, Beguery, Laurent, Belamari, Sophie, Béranger, Karine, Beuvier, Jonathan, Bourras, Denis, Canut, Guylaine, Doerenbecher, Alexis, de Madron, Xavier Durrieu, D'Ortenzio, Fabrizio, Drobinski, Philippe, and Ducrocq, Véronique

Subjects
HYDROLOGIC cycle, OCEAN convection, ATMOSPHERIC boundary layer, HEAT losses
Abstract

The HYdrological cycle in the Mediterranean Experiment (HyMeX) Special Observing Period 2 (SOP2, January 27-March 15, 2013) was dedicated to the study of dense water formation in the Gulf of Lion in the northwestern Mediterranean. This paper outlines the deep convection of winter 2012-2013 and the meteorological conditions that produced it. Alternating phases of mixing and restratification are related to periods of high and low heat losses, respectively. High-resolution, realistic, three-dimensional models are essential for assessing the intricacy of buoyancy fluxes, horizontal advection, and convective processes. At the submesoscale, vertical velocities resulting from symmetric instabilities of the density front bounding the convection zone are crucial for ventilating the deep ocean. Finally, concomitant atmospheric and oceanic data extracted from the comprehensive SOP2 data set highlight the rapid, coupled evolution of oceanic and atmospheric boundary layer characteristics during a strong wind event. [ABSTRACT FROM AUTHOR]

Published
2016
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47. Observations and large-eddy simulations of entrainment in the sheared sahelian boundary layer

Author

Universitat Politècnica de Catalunya. Departament de Física Aplicada, Universitat Politècnica de Catalunya. DF - Dinàmica No Lineal de Fluids, Canut, Guylaine, Couvreux, Fleur, Lothon, Marie, Pino González, David, Saïd, Frédérique, Universitat Politècnica de Catalunya. Departament de Física Aplicada, Universitat Politècnica de Catalunya. DF - Dinàmica No Lineal de Fluids, Canut, Guylaine, Couvreux, Fleur, Lothon, Marie, Pino González, David, and Saïd, Frédérique

Abstract

At the top of the planetary boundary layer, the entrainment of air, which incorporates dry and warm air from the free troposphere into the boundary layer, is a key process for exchanges with the free troposphere since it controls the growth of the boundary layer. Here, we focus on the semi-arid boundary layer where the entrainment process is analyzed using aircraft observations collected during the African Monsoon Multidisciplinary Analysis experiment and large-eddy simulations. The role of the entrainment is specifically enhanced in this region where very large gradients at the planetary boundary-layer top can be found due to the presence of the moist, cold monsoon flow on which the dry, warm Harmattan flow is superimposed. A first large-eddy simulation is designed based on aircraft observations of 5 June 2006 during the transition period between dry conditions and the activemonsoon phase. The simulation reproduces the boundary-layer development and dynamics observed on this day. From this specific case, sensitivity tests are carried out to cover a range of conditions observed during seven other flightsmade in the same transition period in order to describe the entrainment processes in detail. The combination of large-eddy simulations and observations allows us to test the parametrization of entrainment in a mixed-layer model with zero-order and first-order approximations for the entrainment zone. The latter representation of the entrainment zone gives a better fit with the conditions encountered in the Sahelian boundary layer during the transition period because large entrainment thicknesses are observed. The sensitivity study also provides an opportunity to highlight the contribution of shear stress and scalar jumps at the top of the boundary layer in the entrainment process, and to test a relevant parametrization published in the recent literature for a mixed-layer model., Peer Reviewed, Preprint

Published
2011

48. Studying the Boundary Layer Late Afternoon nd Sunset Turbulence (BLLAST)

Author

Universitat Politècnica de Catalunya. Departament de Física Aplicada, Universitat Politècnica de Catalunya. DF - Dinàmica No Lineal de Fluids, Pino González, David, Lothon, Marie, Angevine, Wayne M., Bange, Jens, Beare, R.J., Beyrich, Frank, Canut, Guylaine, Couvreux, Fleur, Delbarre, Hervé, Gibert, Fabien, Jonker, Harm J. J., Lenschow, Donald, Lohou, Fabienne, Mahrt, Larry, Pardyjak, Eric, Sorbjan, Zibgniew, Vilà-Guerau de Arellano, Jordi, Universitat Politècnica de Catalunya. Departament de Física Aplicada, Universitat Politècnica de Catalunya. DF - Dinàmica No Lineal de Fluids, Pino González, David, Lothon, Marie, Angevine, Wayne M., Bange, Jens, Beare, R.J., Beyrich, Frank, Canut, Guylaine, Couvreux, Fleur, Delbarre, Hervé, Gibert, Fabien, Jonker, Harm J. J., Lenschow, Donald, Lohou, Fabienne, Mahrt, Larry, Pardyjak, Eric, Sorbjan, Zibgniew, and Vilà-Guerau de Arellano, Jordi

Abstract

At the end of the afternoon, when the surface heat fluxes start to sharply decrease, the CBL turns from a convective well-mixed layer to an intermittently turbulent residual layer overlying a stably-stratified boundary layer. This transition raises several observational and modeling issues. Even the definition of the boundary layer during this period is fuzzy, since there is no consensus on what criteria to use and no simple scaling laws to apply. Yet it plays an important role in such diverse atmospheric phenomena as transport and diffusion of trace constituents or wind energy production. This phase of the diurnal cycle remains largely unexplored, partly due to the difficulty of measuring weak and intermittent turbulence, anisotropy, horizontal heterogeneity, and rapid time changes. The Boundary Layer Late Afternoon and Sunset Turbulence (BLLAST) project is gathering about thirty research scientists from the European Union and the United States to work on this issue. A field campaign (BLLAST-FE) is planned for spring or summer 2011 in Europe. BLLAST will utilize these observations, as well as previous datasets, large-eddy and direct numerical simulations, and mesoscale modeling to better understand the processes, suggest new parameterizations, and evaluate forecast models during this transitional period. We will present the issues raised by the late afternoon transition and our strategy to study it., Peer Reviewed, Postprint (published version)

Published
2010

49. The entrainment process between the Monsoon flow and the Saharan Air Layer in the West African Monsoon system

Author

Universitat Politècnica de Catalunya. Departament de Física Aplicada, Universitat Politècnica de Catalunya. DF - Dinàmica No Lineal de Fluids, Canut, Guylaine, Couvreux, Fleur, Lothon, Marie, Pino González, David, Saïd, Frédérique, Universitat Politècnica de Catalunya. Departament de Física Aplicada, Universitat Politècnica de Catalunya. DF - Dinàmica No Lineal de Fluids, Canut, Guylaine, Couvreux, Fleur, Lothon, Marie, Pino González, David, and Saïd, Frédérique

Abstract

Peer Reviewed, Postprint (published version)

Published
2010

50. Studying the Boundary Layer Late Afternoon and Sunset Turbulence (BLLAST)

Author

Universitat Politècnica de Catalunya. Departament de Física Aplicada, Universitat Politècnica de Catalunya. DF - Dinàmica No Lineal de Fluids, Vilà-Guerau de Arellano, Jordi, Pino González, David, Pardyjak, Erick, Mahrt, Larry, Lohou, Fabienne, Jonker, Harm J. J., Gioli, Beniamino, Gibert, Fabien, Durand, Pierre, Lothon, Marie, Lenschow, Donald, Angevine, Wayne, Bange, Jens, Beare, Robert, Canut, Guylaine, Couvreux, Fleur, Delbarre, Hervé, Universitat Politècnica de Catalunya. Departament de Física Aplicada, Universitat Politècnica de Catalunya. DF - Dinàmica No Lineal de Fluids, Vilà-Guerau de Arellano, Jordi, Pino González, David, Pardyjak, Erick, Mahrt, Larry, Lohou, Fabienne, Jonker, Harm J. J., Gioli, Beniamino, Gibert, Fabien, Durand, Pierre, Lothon, Marie, Lenschow, Donald, Angevine, Wayne, Bange, Jens, Beare, Robert, Canut, Guylaine, Couvreux, Fleur, and Delbarre, Hervé

Abstract

At the end of the afternoon, when the surface heat fluxes start to sharply decrease, the CBL turns from a convective well-mixed layer to an intermittently turbulent residual layer overlying a stably-stratified boundary layer. This transition raises several observational and modelling issues. Even the definition of the boundary layer during this period is fuzzy, since there is no consensus on what criteria to use and no simple scaling laws to apply. Yet it plays an important role in such diverse atmospheric phenomena as transport and diffusion of trace constituents or wind energy production. This phase of the diurnal cycle remains largely unexplored, partly due to the difficulty of measuring weak and intermittent turbulence, anisotropy, horizontal heterogeneity, and rapid time changes. The Boundary Layer Late Afternoon and Sunset Turbulence (BLLAST) project is gathering about thirty research scientists from the European Union and the United States to work on this issue. A field campaign (BLLAST-FE) is planned for spring or summer 2011 in Europe. BLLAST will utilize these observations, as well as previous datasets, large-eddy and direct numerical simulations, and mesoscale modelling to better understand the processes, suggest new parameterisations, and evaluate forecast models during this transitional period. We will present the issues raised by the late afternoon transition and our strategy to study it., Peer Reviewed, Postprint (published version)

Published
2010

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