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Timothy DelSole and Michael K. Tippett

predictable components because trends and other low-frequency fluctuations are highly predictable. The fact that the secular trend is significant prior to 1980 and much smaller after 1980 explains why predictability identified in the training period fails to verify in the assessment period. Indeed, because the trend is substantially reduced in the assessment period, the Mahalanobis signal evaluated in the assessment period is negative. The negative value arises because the linear regression model for this

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Hing Ong and Paul E. Roundy

when β → 0. Table 1. Categories of equatorially confined wave solutions. Development of dynamical cores for atmospheric models usually benefits from research about deterministic initial value problems. For example, numerical benchmarks of baroclinic waves (e.g., Jablonowski and Williamson 2006 ; Ullrich et al. 2014 ) are widely used to test the model performance in the midlatitudes. On the other hand, in the tropics, simply testing the dry dynamics overstratifies the atmosphere, but adding

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Jean-François Vinuesa and Fernando Porté-Agel

or a priori specification, it is evaluated directly from the resolved scales by using a dynamic procedure ( VP05 ). For the scalar covariance, the dynamic procedure is based on the Germano identity ( Germano et al. 1991 ): where ϒ is a resolved covariance that can be determined using the resolved scales and Ξ = − is the subgrid covariance at a test-filter scale (2Δ). Using the similarity model, Ξ can be expressed as where the caret represents a spatial filtering operation applied at scale 4Δ

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Xiaqiong Zhou, Bin Wang, Xuyang Ge, and Tim Li

have not been examined. The primary goals of this study are (a) to investigate whether the thermodynamic structures differ between the concentric eyewall TCs with and without large intensity fluctuation and (b) to investigate whether the secondary eyewalls and associated intensity fluctuation simulated by numerical models are consistent with the observations. 2. Data and methodology The Tropical Rainfall Measuring Mission (TRMM) 2A12 dataset ( Olson et al. 2006 ) is generated from TRMM Microwave

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Adam H. Monahan and John C. Fyfe

1. Introduction The leading principal component analysis (PCA) mode of extratropical zonal-mean zonal wind variability is known as the zonal index (e.g., Lorenz and Hartmann 2001 ). The spatial structure corresponding to this mode [i.e., the empirical orthogonal function (EOF)] is found to be a dipole in observations and in a range of models from randomly forced barotropic β -plane dynamics (e.g., Vallis et al. 2004 ) through dry dynamical cores (e.g., Fyfe and Lorenz 2005 ) to complex

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Samson Hagos, Zhe Feng, Sally McFarlane, and L. Ruby Leung

their comparative relationships to the lifetime of the convective systems. Application of the tracking algorithm, originally designed for satellite observations, onto the cloud systems simulated by a high-resolution regional model allows a thorough evaluation of the model's ability to reproduce the cloud statistics observed by satellite and, more importantly, enables examination of the environmental processes before and during the lifetime of the convective system. 2. Methodology a. Model and

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R. J. Zammett and A. C. Fowler

. Geophys. Res. , 106 , D24 . 33781 – 33788 . Lefebre , F. , X. Fettweis , H. Gallée , J-P. van Ypersele , P. Marbaix , W. Greuell , and P. Calanca , 2005 : Evaluation of a high-resolution regional climate simulation over Greenland. Climate Dyn. , 25 , 99 – 116 . Nappo , C. J. , and K. S. Rao , 1987 : A model study of pure katabatic flows. Tellus , 39A , 61 – 71 . Ockendon , H. , and J. R. Ockendon , 1995 : Viscous Flow . Cambridge University Press, 113 pp

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S. B. Trier, C. A. Davis, and D. A. Ahijevych

cycle over the mountains and the adjacent plains using a model that permitted explicit deep convection. Based on their two-dimensional simulations, they explained the life cycle of warm-season convection in the lee of the mountains and adjacent plains as an outgrowth of the thermally forced west-to-east mountain–plains solenoid (MPS) modified by latent heat release from deep convection. However, earlier case studies (e.g., Wetzel et al. 1983 ) and recent observationally based climatologies (e

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Dehai Luo and Zhe Chen

by Luo (2005) , who found that the topography term is not explicitly included in the forced NLS equation. The absence of LSC topography in the NLS equation derived by Luo (2005) is due to the lack of the higher-order wave–topography interaction in his model. In this paper, we will further extend this theoretical model to include the high order wave–topography interaction to evaluate the different roles of LSC topography and synoptic-scale transients in the blocking formation. It must be

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Masahiro Sugiyama

al. 2008 ). Deep convection, on the other hand, affects the tropospheric humidity budget in various ways. Such an interaction leads to a new kind of dynamical mode called the moisture mode (defined below). Theoretical papers on the moisture mode include Yu and Neelin (1994) , Sobel et al. (2001) , Fuchs and Raymond (2002 , 2005 , 2007) , and Bony and Emanuel (2005) , whereas Sobel and Bretherton (2003) and Grabowski and Moncrieff (2004) , for example, performed modeling studies. The

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