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Giacomo Masato, Brian J. Hoskins, and Tim J. Woollings

between a block and a synoptic ridge purely semantic? The aim of this note is to address this question by comparing observations of blocking with the output from a first-order Markov model, as suggested by Tyrlis and Hoskins (2008a , hereafter TH08a ). Such a model is the simplest possible statistical red noise model, and yet many of the characteristics of transient synoptic-scale eddies can be well modeled by such a process ( Branstator 1995 ; Whitaker and Sardeshmukh 1998 ). If the observed

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Xiouhua Fu, Bin Wang, Duane E. Waliser, and Li Tao

, M. Newman , J. D. Glick , and J. E. Schemm , 2000 : Medium-range forecast errors associated with active episodes of the Madden–Julian oscillation. Mon. Wea. Rev. , 128 , 69 – 86 . Hollingsworth , A. , K. Arpe , M. Tiedtke , M. Capaldo , and H. Savijarvi , 1980 : The performance of a medium-range forecast model in winter—Impact of physical parameterizations. Mon. Wea. Rev. , 108 , 1736 – 1773 . IFRC , 2000 : World Disaster Report: Focus on Recovery . IFRC, 392

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Alvaro Semedo, Øyvind Saetra, Anna Rutgersson, Kimmo K. Kahma, and Heidi Pettersson

wind profile over the ocean, under swell conditions, is no longer logarithmic makes the correct evaluation of the roughness length a cumbersome problem (see Figs. 3 and 7 in Smedman et al. 2003 ). For the model sensitivity tests to roughness length variations, several formulations are used ( Table 1 ). Once again the original profile evaluated with z 0 = 10 −5 m is kept as a reference and is shown as a solid line in Fig. 7 . The profiles corresponding to several roughness lengths from the

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Tempei Hashino and Gregory J. Tripoli

cloud-resolving models (CRMs), particle properties of crystals and aggregates are typically assigned by categories, given the computational cost and the uncertainties associated with a lack of physical understanding. The variability of aggregation processes resulting from particle history or habits is directly related to the number of assumed categories. Thus, this approach is not ideal to study the variability. The simulation of habits and sizes is particularly important in association with the

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George H. Bryan and Richard Rotunno

analytical model of Emanuel (1986 , hereafter E86) . The purpose of this article is to investigate the source of this discrepancy. To this end, we evaluate the underlying assumptions of Emanuel’s potential intensity theory (E-PI; E86 ) using output from numerical model simulations in which steady tropical cyclone intensity greatly exceeds E-PI. The same methodology was undertaken by PM03 . They ultimately concluded that the underlying thermodynamic assumption in E-PI (moist slantwise neutrality) was

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Christopher M. Rozoff, James P. Kossin, Wayne H. Schubert, and Pedro J. Mulero

of the synoptic-scale storm environment. This is not the case, however, and it is fairly typical for storms to strengthen or weaken, sometimes rapidly, without any clear commensurate changes in the storm environment. Although the specific processes involved remain an open question, this behavior is widely believed to result from internal mesoscale processes that can have a profound effect on how storm intensity evolves. This implies that the ability to model and ultimately predict hurricane

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Curt Covey, Aiguo Dai, Dan Marsh, and Richard S. Lindzen

. Stouffer , and K. E. Taylor , 2007 : The WCRP CMIP3 multimodel dataset: A new era in climate change research. Bull. Amer. Meteor. Soc. , 88 , 1383 – 1394 . Pirscher , B. , U. Foelsche , M. Borsche , G. Kirchengast , and Y.-H. Kuo , 2010 : Analysis of migrating diurnal tides detected in FORMOSAT-3/COSMIC temperature data. J. Geophys. Res. , 115 , D14108 . doi:10.1029/2009JD013008 . Randall , D. A. , and Coauthors 2007 : Climate models and their evaluation. Climate

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Gwendal Rivière

–contraction process (called hereafter the barotropic regeneration process) takes place preferentially east of the mountains in a confluent region or north of the subtropical jets. It is worth noting that this process is a transient nonmodal phenomenon that may occur without the presence of barotropic instability, as shown theoretically in simple linear barotropic models by Farrell (1989) and Lee (1995) . The transition from elongation to contraction stages requires a rapid change of the environment in which

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Maurizio Fantini and Piero Malguzzi

light-thermodynamics environment, the argument given above can be modified to show that neutral buoyancy ( T p υ ) f = ( T e υ ) f coincides with the tangent to θ * e contours. Given a numerical model and environmental thermodynamic quantities, the direction of neutral buoyancy can be obtained numerically by letting the model evaluate the parcel virtual temperature T p υ ( p + Δ p ) after a displacement Δ p , and then solving for (Δ x , Δ z ) the following system: In the cases in which we

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Kara J. Sulia, Zachary J. Lebo, Vanessa M. Przybylo, and Carl G. Schmitt

the loss of larger and less pristine ice crystals. The effect of nonspherical ice–ice aggregation is explored herein. Minute intricacies associated with ice growth from vapor deposition were explored through development of the adaptive ice habit model in Harrington et al. (2013a) . This work extends such development to include the effect of nonspherical ice–ice aggregation and is analyzed herein. While a number of investigations of processes affected by the nonspherical growth of ice crystals

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