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Juan Fang, Olivier Pauluis, and Fuqing Zhang

) introduces the concept of isentropic analysis for convective motions in which θ e is used to replace the horizontal coordinates. The PM13 technique uses the equivalent potential temperature to replace both horizontal coordinates x and y by sorting air parcels at different altitude z in terms of their θ e . Via averaging the flow properties at a constant value of θ e , a comprehensive description of the convective motions can be achieved in the thermodynamic space θ e – z . Major advantages

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Roger Marchand, Nathaniel Beagley, Sandra E. Thompson, Thomas P. Ackerman, and David M. Schultz

Forecasts (ECMWF) Re-Analysis (ERA-40) data in the Tropics by examining model data as a function of cloud regime. These model shortcomings were not apparent from annually averaged values. In this analysis, we aggregate local-scale properties of clouds according to the synoptic-scale state. Specifically, we examine vertical mean profiles of cloud occurrence obtained from a vertically pointing millimeter-wavelength cloud radar operated by the U.S. Department of Energy (DOE) Atmospheric Radiation

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Derek J. Posselt, Fei He, Jennifer Bukowski, and Jeffrey S. Reid

values of the other parameters, the OAT analysis will not detect this. Morris screening, or Morris one-at-a-time techniques (MOAT; Morris 1991 ; Covey et al. 2013 ) are an extension to OAT perturbation techniques that compute the change in an outcome y for a given change in input x j several times: for multiple values of x j , and for various baseline (or reference) values of the other parameters. As in OAT, the computational cost of MOAT grows linearly with the number of control

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O. Bokhove

can be inferred from their variational or Hamiltonian formulations, and henceforth whether it would lead us to novel solutions. This paper provides the conservative structure, which can form the starting point for the development of conservative numerical integration techniques in atmospheric and oceanic forecasting models. The Eulerian variational principles may form an alternative route for attempting to find conservative discretizations. Consider for example the Eulerian variational principle

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Kyong-Hwan Seo, Hyun-Ju Lee, and Dargan M. W. Frierson

surface temperature over East Asia and the Rossby wave propagation plays a role over North America and eastern Europe. In addition, we demonstrate the occurrence rate of extreme warm/cold events for strong MJO cases. The information gained from this study can be useful for improving the skill of long-term temperature prediction. We show here that the MJO is a predictability source on the intraseasonal time scale for the forecast of strong warm/cold events over these continents. 2. Data and methodology

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Robert F. Rogers, Michael L. Black, Shuyi S. Chen, and Robert A. Black

distribution of latent heat release is quite challenging, however, and improving our understanding and forecasting of intensity and rainfall remains an elusive goal for the operational and research communities. For example, the forecast skill for intensity is only about one-half (one-third) of that for track at 36 h (72 h) forecast time ( DeMaria and Gross 2003 ), while standardized techniques for evaluating tropical cyclone rainfall are only now being developed ( Marchok et al. 2007 ). Continuing

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Silvio Gualdi, Antonio Navarra, and Hans von Storch

recent observational study Hendon and Salby (1994) computed a composite life cycle of the MJO signal present in 11 years (1979–89) of European Centre for Medium-Range Weather Forecasts (ECMWF) and National Meteorological Center (NMC), now the National Centers for Environmental Prediction, analyses. In agreement with the results previously found in the First GARP (Global Atmospheric Research Program) Global Experiment dataset and in the Geophysical Fluid Dynamics Laboratory (GFDL) climate model by

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A. Navarra and K. Miyakoda

general circulation model (GCM) are formulated and applied to a studyof low-frequency atmospheric variability in the extratropics, and long-range forecasting research. A steady linearversion of the anomaly model is treated by a matrix method. This model consists of nine vertical levels, 15wave rhomboidal truncation, primitive equation system, and a fixed basic state, which is three-dimensionallyvariable. The matrix to be handled is extremely large, but can be solved using IQylov's technique. The

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Jeroen Oortwijn

patterns of a set of four Euro-Atlantic regimes. Among these are a blocking (BL) and strong zonal flow (SZF) regime. A striking result is that of all regimes, the BL precursors are most successfully classifiable, whereas the prediction of blocking appears to be difficult. Studies on the predictability of blocking with the European Centre for Medium-Range Weather Forecasts (ECMWF) operational model ( Tibaldi and Molteni 1990 ; Palmer et al. 1990 ; Tibaldi et al. 1994 ) showed that blocking onset is

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Zhanhong Ma

1. Introduction The progress in tropical cyclone (TC) intensity forecast improvement has been slow in recent decades relative to the rate of improvement in TC track prediction, since the intensity change is influenced by multiscale processes, such as large-scale environmental factors, vortex dynamics, and air–sea interactions ( Emanuel et al. 2004 ; Black et al. 2007 ; Elsberry et al. 2007 ; Rogers et al. 2013 ; DeMaria et al. 2014 ; Colomb et al. 2019 ). The sudden intensity change of TCs

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