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Tobias Kremer, Elmar Schömer, Christian Euler, and Michael Riemer

settings have been used for the parameterization schemes: inter alia a turbulent kinetic energy-based turbulence scheme, a shallow-convection scheme with mass-flux closure after Tiedtke (1989) , and a single-moment ice microphysics scheme (including graupel). The parameterization schemes are described in Doms et al. (2011) and more details on the setup of the simulation are given in Euler et al. (2019) . Our simulation domain spans from 22° to 54°N and from 40° to 70°W. Boundary and initial

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Andreas Schäfler, George Craig, Heini Wernli, Philippe Arbogast, James D. Doyle, Ron McTaggart-Cowan, John Methven, Gwendal Rivière, Felix Ament, Maxi Boettcher, Martina Bramberger, Quitterie Cazenave, Richard Cotton, Susanne Crewell, Julien Delanoë, Andreas Dörnbrack, André Ehrlich, Florian Ewald, Andreas Fix, Christian M. Grams, Suzanne L. Gray, Hans Grob, Silke Groß, Martin Hagen, Ben Harvey, Lutz Hirsch, Marek Jacob, Tobias Kölling, Heike Konow, Christian Lemmerz, Oliver Lux, Linus Magnusson, Bernhard Mayer, Mario Mech, Richard Moore, Jacques Pelon, Julian Quinting, Stephan Rahm, Markus Rapp, Marc Rautenhaus, Oliver Reitebuch, Carolyn A. Reynolds, Harald Sodemann, Thomas Spengler, Geraint Vaughan, Manfred Wendisch, Martin Wirth, Benjamin Witschas, Kevin Wolf, and Tobias Zinner

diabatic processes are particularly active as a result of relatively high sea surface temperatures and the intensification of the jet stream as the high latitudes cool. Many of the weather phenomena central to the growth of disturbances on the jet stream and midlatitude predictability are active in fall, such as extratropical cyclones with intense fronts and warm conveyor belts (WCBs), carrying air from the oceanic boundary layer into ridges at the tropopause level. There is also the possibility of

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Christian Barthlott and Corinna Hoose

( Rosenfeld et al. 2008 ). The larger water load at the freezing level results in an additional release of latent heat, leading to an invigoration of convection with additional rainfall. Even in absence of such a thermodynamic invigoration, Fan et al. (2013) found that aerosol’s microphysical effects can lead to a dramatic increase in cloud cover, cloud-top height, and cloud thickness at the mature and dissipation stages by inducing larger amounts of smaller but longer-lasting ice particles in the

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Christian Euler, Michael Riemer, Tobias Kremer, and Elmar Schömer

, and the translation of the TC into a thermodynamic environment that gradually becomes less favorable for tropical development, namely a drier and cooler environment, including decreasing sea surface temperature. The transition from a tropical to an extratropical cyclone is a highly asymmetric process with rapidly changing dynamics. The involved airstreams during ET can therefore be expected to be nontrivial variants of the airstreams of mature TCs and of the conveyor belts of extratropical

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Tobias Selz

the use of a metric like continuous ranked probability score and tests against a calibrated model climate distribution are beyond our computing capacities. We further note that this study refers to instantaneous gridpoint fields and to atmospheric turbulence only. Other Earth system components like the ocean, the stratosphere, the ground, or sea ice can enhance predictability and may lead to skillful predictions beyond the limit estimated here. Such enhancements of predictability can however

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Toward a Systematic Evaluation of Warm Conveyor Belts in Numerical Weather Prediction and Climate Models. Part I: Predictor Selection and Logistic Regression Model

Julian F. Quinting and Christian M. Grams

. Roy. Meteor. Soc. , 137 , 553 – 597 , https://doi.org/10.1002/qj.828 . 10.1002/qj.828 Dreiseitl , S. , and L. Ohno-Machado , 2002 : Logistic regression and artificial neural network classification models: A methodology review . J. Biomed. Inform. , 35 , 352 – 359 , https://doi.org/10.1016/S1532-0464(03)00034-0 . 10.1016/S1532-0464(03)00034-0 Drobot , S. D. , and J. A. Maslanik , 2002 : A practical method for long-range forecasting of ice severity in the Beaufort Sea . Geophys

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Thomas Engel, Andreas H. Fink, Peter Knippertz, Gregor Pante, and Jan Bliefernicht

TRMM radar data (e.g., Gosset et al. 2013 ; Pfeifroth et al. 2016 ). The period used in the present study is 1983–2014. 3. Methods a. Analysis of atmospheric dynamics Both Ouagadougou and Dakar are located in the Sahel, a region stretching between about 12° and 18°N from the Atlantic coast to the Red Sea (see Fig. 1a ). This area is characterized by the transition from the arid conditions of the Sahara with less than 200 mm rainfall per year to a more humid climate equatorward. The West African

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Kevin Bachmann, Christian Keil, George C. Craig, Martin Weissmann, and Christian A. Welzbacher

microphysics scheme accounting for cloud water, rainwater, cloud ice, snow, and graupel ( Lin et al. 1983 ; Reinhardt and Seifert 2006 ); as well as a two-stream radiation scheme ( Ritter and Geleyn 1992 ). The asymptotic vertical mixing length of the boundary layer turbulence scheme is set to 500 m. All idealized experiments are initialized with horizontally homogeneous initial conditions (IC), based on a sounding from Payerne in Switzerland (CH, Radiosonde 06610; Fig. 1 ), observed at 1200 UTC 30 July

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