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K. L. Swanson, T. N. Palmer, and R. Vautard

1. Introduction The generation of more accurate analyzed meteorological fields for numerical weather forecasting is one factor that motivates current research into advanced data assimilation techniques ( Ghil and Malanotte-Rizzoli 1991 ). In general, the ability of any assimilation technique to estimate the state of the atmosphere will depend strongly upon the quality of the observations, as coarse spatial and temporal observational coverage or large random errors in the observations will lead

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Fuqing Zhang, Y. Qiang Sun, Linus Magnusson, Roberto Buizza, Shian-Jiann Lin, Jan-Huey Chen, and Kerry Emanuel

additional predictable forecast lead time. Achieving this additional predictability limit can greatly benefit society by saving lives and property but requires continued coordinated efforts by the entire meteorology community and beyond to design more accurate NWP models performing at refined resolutions, improve and enhance the observing techniques and networks, and make better use of observations with advanced data assimilation and computing techniques. It is possible those two individual local weather

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Greg J. Holland

past time when we know all other cyclone parameters, and then use this value to predict the cyclone motion from present data. The solution technique is then as shown in Table 2. For case study or forecast applications, the model is first "initialized" by determining the effective radius from immediate past data. Then present data are incor porated and the future cyclone motion is forecast using the same effective radius. For "what if?" sci entific applications a standard cyclone is defined at the

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Jan-Huey Chen, Melinda S. Peng, Carolyn A. Reynolds, and Chun-Chieh Wu

with nearby TCs ( Wu et al. 2003 ; Peng and Reynolds 2005 ; Yang et al. 2008 ). In the final stage, they may recurve and transition into an extratropical cyclone or make landfall and dissipate. TC forecast inaccuracy comes both from errors in the numerical weather prediction models and from errors in the analyzed initial conditions. Concerning the latter, the lack of observations over the open-ocean regions where TCs spend most of their lifetime degrades the quality of initial conditions and the

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Eric J. Pitcher

VOL. 34, NO. 1 JOURNAL OF THE ATMOSPHERIC SCIENCES JANUARY 1977Application of Stochastic Dynamic Prediction to Real Data E~c J. P~cm~~National Meteorological Center, National Weather Service, NOAA, Washington, D.C. 20233(Manuscript received 30 March 1976, in revised form 28 September 1976)ABSTRACT The technique of stochastic dynamic prediction proposed by Epstein is applied to atmospheric data

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Lewis Mitchell and Georg A. Gottwald

plethora of different methods to construct stochastic subgrid-scale parameterizations, including phenomenological approaches such as randomization of existing deterministic parameterization schemes (e.g., Buizza et al. 1999 ), energetic backscattering (e.g., Frederiksen and Davies 1997 ; Shutts 2005 ), data-driven techniques such as Markov chains (e.g., Crommelin and Vanden-Eijnden 2008 ), and systematic approaches using stochastic homogenization (e.g., Majda et al. 1999 , 2003 ). The specific

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Åke Johansson, Anthony Barnston, Suranjana Saha, and Huug van den Dool

coupled data assimilation procedure, even though work along these lines is now under way at several institutions around the world. An alternative to using coupled dynamical models is to use empirical methods. Empirical long-range forecasting is an old activity ( Rossby 1941 ; Namias 1953 ) with documented, but rather modest, skill ( Nicholls 1980 ; Nap et al. 1981 ; Livezey 1990 ). Through access to the relatively newly available global datasets, and through the development of new techniques to

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John C. Freeman Jr

thetropical easterlies are often a one-dimensional current with an inversion, the techniques are theoreticallyapplicable to them. The theory admits three types of disturbances oriented normal to the current: a rarefaction wave, a compression wave, and a jump. The mathematical theory is shown to conform with generalpractical and practiced tropical forecasting methods and to agree with specific examples.I1. Preliminary remarksThe easterly waves` of Riehl and Bonnot [14] havebeen located and used for

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Urs Germann, Isztar Zawadzki, and Barry Turner

, in particular at small scales ( Lee and Zawadzki 2005 ). To a first approximation we can neglect these inadequacies and assume that the distribution of radar reflectivity represents the precipitation field. b. Benchmark concept The concept of taking the skill of a forecasting technique, such as persistence of radar precipitation patterns, as a measure of predictability goes back to Lorenz (1973) who said: “Regardless of what may be indicated by theory, a conclusive proof that partial

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Edward J. Harrison and Russell L. Elsberry

meshing technique is described, as well as the method of keeping the fine-meshgrid centered over the region of interest. Forecasts arecompared to those of uniform grid intervals. Themeshing technique is then extended to a two-dimensional (Y-P), ten-level, primitive equation model. The12351236 J O U R N A I. O F T H E A T M O S P H E R I C S C 1 E N C E S VoLvsu; 29analytic initial state sinmlates a small (about threegrid interval) scale

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