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

probability distributions allows a point mass for zero precipitation and flexible modeling in positive precipitation accumulations, depending on the specifics of the ensemble forecast at hand. For mathematical details we refer to the original paper by Scheuerer (2014) . Postprocessing techniques rely on statistical parameters that need to be estimated from training data, comprising forecast–observation-pairs from the TRMM pixel at hand and typically from a rolling training period consisting of the n

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

dispersion errors and biases. Statistical postprocessing addresses these deficiencies and realizes the full potential of ensemble forecasts ( Gneiting and Raftery 2005 ). Additionally, it performs implicit downscaling from the model grid resolution to finer resolutions or station locations. The correction of systematic forecast errors is based on (distributional) regression techniques and, depending on the need of the user, several approaches are at hand ( Schefzik et al. 2013 ; Gneiting 2014 ). Hamill

Open access
Stephan Rasp and Sebastian Lerch

the mean value and standard deviation of the 2-m temperature forecasts. 3. Benchmark postprocessing techniques a. Ensemble model output statistics Within the general EMOS framework proposed by Gneiting et al. (2005) , the conditional distribution of the weather variable of interest, , given ensemble predictions , is modeled by a single parametric forecast distribution with parameters : The parameters vary over space and time, and depend on the ensemble predictions through suitable link

Open access
Michael Maier-Gerber, Michael Riemer, Andreas H. Fink, Peter Knippertz, Enrico Di Muzio, and Ron McTaggart-Cowan

this study is split into “cyclone” and “no-cyclone” groups to elucidate dynamic causes limiting predictability of the pre-Chris cyclone’s formation. The group memberships are determined based on similarity between forecast tracks and the analysis track using a dynamic time warping technique (see section 2c for details). This track-based approach for the identification of equivalent cyclones in the forecast members ensures that those are excluded that are of substantially different origin from the

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

Palmer 2011 ). Second, those ensembles require refined initial conditions, which can only be obtained by data assimilation (DA) of spatially dense observations on kilometer scales ( Johnson and Wang 2016 ). And third, novel techniques are necessary to verify the forecasts and assess their skill with observations of high spatial and temporal resolution ( Cintineo and Stensrud 2013 ). Estimates of the forecast horizon of storm-scale features remain rather pessimistic, being on the order of only a few

Free access
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

challenging circumstances in weather situations with reduced predictability (i.e., in situations with large changes between subsequent forecasts). Therefore, NAWDEX combined modern forecasting tools, including ensemble and adjoint-based diagnostics, and new visualization techniques to incorporate forecast uncertainty in the planning process (see the “Forecast products for investigating forecast uncertainty” sidebar). Fig . 2. Tracks of consecutively numbered RFs of (a) HALO (97 flight hours during 13 RFs

Open access
Hilke S. Lentink, Christian M. Grams, Michael Riemer, and Sarah C. Jones

, and R. L. Elsberry , 2000 : Extratropical transition of western North Pacific tropical cyclones: An overview and conceptual model of the transformation stage . Wea. Forecasting , 15 , 373 – 395 , https://doi.org/10.1175/1520-0434(2000)015<0373:ETOWNP>2.0.CO;2 . 10.1175/1520-0434(2000)015<0373:ETOWNP>2.0.CO;2 Kossin , J. P. , and C. S. Velden , 2004 : A pronounced bias in tropical cyclone minimum sea level pressure estimation based on the Dvorak technique . Mon. Wea. Rev. , 132

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Mirjam Hirt, Stephan Rasp, Ulrich Blahak, and George C. Craig

.1175/1520-0493(1997)125<0527:TRDOEM>2.0.CO;2 . 10.1175/1520-0493(1997)125<0527:TRDOEM>2.0.CO;2 Wernli , H. , M. Paulat , M. Hagen , and C. Frei , 2008 : SAL—A novel quality measure for the verification of quantitative precipitation forecasts . Mon. Wea. Rev. , 136 , 4470 – 4487 , https://doi.org/10.1175/2008MWR2415.1 . 10.1175/2008MWR2415.1 Wernli , H. , C. Hofmann , and M. Zimmer , 2009 : Spatial forecast verification methods intercomparison project: Application of the SAL technique . Wea. Forecasting

Free access
Paolo Ghinassi, Georgios Fragkoulidis, and Volkmar Wirth

; Fragkoulidis et al. 2018 ). Furthermore, it has been argued that the existence of RWPs has implications for predictability ( Lee and Held 1993 ; Grazzini and Vitart 2015 ), which is particularly relevant in the case of high-impact weather. The importance of RWPs has motivated the development of various techniques for their identification and analysis. These techniques include the famous Hovmöller diagram ( Hovmöller 1949 ), the analysis of eddy kinetic energy (short EKE; Chang and Orlanski 1993 ), the

Open access
Christian Barthlott and Corinna Hoose

.g., heat bubble, cold pool, mountain) is needed to initiate convection. As was pointed out by Noppel et al. (2010) , such idealized simulations often show different sensitivities of aerosol–cloud interactions than the simulation of real cases. In this paper, we expand this line of investigation by performing convection-resolving simulations of real weather events, but applying a novel technique of systematically modifying temperature profiles of the initial and boundary data. The modified temperature

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