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Peter Vogel, Peter Knippertz, Andreas H. Fink, Andreas Schlueter, and Tilmann Gneiting

horizon to few days at scales of 100 km ( Judt 2020 ). Third, small-scale physical processes such as cloud microphysics and radiation can relatively easily affect scales large enough to be of interest to predictions through their effects on the vertical profiles of latent (and radiative) heating and thus divergent wind. For example, convective invigoration by increased cloud condensation nuclei ( Rosenfeld et al. 2008 ) and larger or longer-lived anvils ( Fan et al. 2013 ) affect convective

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Stephan Rasp, Tobias Selz, and George C. Craig

flux in any finite region holds to a reasonable degree of approximation. Although the convective cases considered here are much more complex than the radiative–convective equilibrium environment for which the theory was first developed and tested, the additional complexity does not completely alter the behavior. Since it is the variability scaling that relates the amplitude of convective variability to both the convective closure and the model resolution, its use in stochastic parameterization is

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Joël Arnault, Thomas Rummler, Florian Baur, Sebastian Lerch, Sven Wagner, Benjamin Fersch, Zhenyu Zhang, Noah Kerandi, Christian Keil, and Harald Kunstmann

pressure coordinate ( Skamarock and Klemp 2008 ), with 50 vertical levels and a pressure top at 10 hPa. Subgrid processes additionally parameterized are the longwave and shortwave radiative fluxes [ Mlawer et al. (1997) and Dudhia (1989) , respectively], cloud microphysics ( Hong and Lim 2006 ), atmospheric turbulence, and surface heat and moisture fluxes as follows. Fig . 1. (a) Terrain elevation (m MSL) of the 2.8-km-resolution WRF domain. The height scale is given by the colored bar to the right

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Volkmar Wirth, Michael Riemer, Edmund K. M. Chang, and Olivia Martius

conservation of total energy following the 3D flow); is the velocity vector, ω is the pressure vertical velocity, and α is the specific volume. In (3) , the first two terms on the right-hand side represent baroclinic and barotropic conversion, respectively. The third term on the right-hand side also represents an energy transfer between the mean flow and the eddies, but averages out to zero in the time mean. Following Orlanski and Sheldon (1993) , the energy flux can be written as follows: where

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Georgios Fragkoulidis and Volkmar Wirth

given by the ratio of wave activity flux to wave activity density (e.g., Chang 2001b ). To this end, Northern Hemisphere winter climatologies of the 300-hPa wave activity flux M T and density M based on the formulation of Plumb (1986) for transient eddies are presented here for reference. The involved formulation and results for eddies of various frequencies are included in section 7 of the SM ( Fig. S19 ). In accordance with the results of Plumb (1986) , the radiative component of M T in

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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

Weather project ( Jones and Golding 2015 ) and aims to provide the observational foundation to further investigate cloud diabatic processes and radiative transfer in North Atlantic weather systems, which will form the basis for future improvements in the prediction of HIW over Europe. THE ROLE OF DIABATIC PROCESSES. Weather in Europe strongly depends on the life cycles of Rossby waves that propagate along the slowly varying part of the North Atlantic jet stream ( Martius et al. 2010 ). The strong

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

://www.ncdc.noaa.gov/isd ). Without nearby stations, it is often impossible to distinguish erroneous data from real events with centennial return periods. Since the advent of geostationary satellites around the 1980s and subsequently the launch of the Tropical Rainfall Measuring Mission (TRMM) satellite in 1997, daily satellite-based rainfall estimations (SRFEs) have opened new avenues for quality checks of gauge data. However, these SRFEs are based on proxies related to radiative and emissive properties of cloud hydrometeors at

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Marlene Baumgart, Paolo Ghinassi, Volkmar Wirth, Tobias Selz, George C. Craig, and Michael Riemer

service ( Zängl et al. 2015 ). The model was run with a horizontal resolution corresponding to about 40 km. Convection is parameterized using the stochastic Plant–Craig (PC) convection scheme ( Plant and Craig 2008 ). The PC scheme uses a random value of the convective mass flux, which is drawn from a quasi-equilibrium distribution that uses the ensemble mean mass flux given by a standard CAPE closure. For each ensemble member a different seed is used to generate the random draw, resulting in a

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Peter Vogel, Peter Knippertz, Andreas H. Fink, Andreas Schlueter, and Tilmann Gneiting

, even when using the same resolution of 12 km. In the explicit-convection simulation, greater latent and radiative heating to the north weakens the monsoon flow, delays the diurnal cycle, and convective cold pools provide an essential component to the monsoon flux. We suspect that some or all of these effects are misrepresented in global EPS forecasts. The fact that EPS precipitation forecasts are so poor over northern tropical Africa is a strong demonstration of the complexity of the underlying

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Christian Barthlott and Corinna Hoose

and simulating clouds in different environments are needed. The COSMO model uses a rotated latitude–longitude grid with terrain-following hybrid height coordinates. Deep convection is resolved explicitly, while shallow convection is parameterized using a modified Tiedtke mass-flux scheme with moisture-convergence closure ( Tiedtke 1989 ). Shallow convection is nonprecipitating and limited to a cloud depth of 250 hPa. Only temperature and moisture are directly affected by shallow convection (for

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