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Daniel L. Rudnick, Ganesh Gopalakrishnan, and Bruce D. Cornuelle

of an LCE by separation from the LC happens irregularly every several months, and there can be a number of LCEs in the GoM at one time. Prediction of LCE formation events is central to accurate forecasting of GoM circulation. Cyclonic eddies (CEs), sometimes called Loop Current frontal eddies ( Walker et al. 2009 ), exist on the periphery of the LC and LCE. These CEs are much smaller than the LCE, but they are thought to have a controlling influence on the LCE, including its separation from the

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W. B. Tucker III

fields, the NCC objectiveanalysis fields are a by-product of the complex dataassimilation scheme (McPherson et al., 1979) that isused to update NMC's global prediction model. Thekey difference here is that the interpolation to thespatial grid takes place in the prediction model's terrain-following sigma vertical coordinate system. Under this procedure, the height of an isobaric surfaceis not required. The OI procedure merges a first-guessfield (a previous model forecast) with station or upperair

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John Derber and Anthony Rosati

process. This quality check involved the comparison of the current model solution to the observations. This final procedure will be de scribed in mole detail in the next section along with the rest of the analysis and insertion procedures.4. Data analysis and insertion technique The observed data were inserted into the numericalmodel by applying a correction to the forecast temperature field at every model timestep (every 2 hours).The correction field was created using data from 15days to either

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A. F. Bennett and P. E. Kloeden

discontinuously in the ill-posedcase. However, we agree that for the purposes ofoperational short-range forecasting, ad hoc smoothing techniques such as digital filtering are reasonable. Any interpretations of these forecasts in termsof continuum mechanical phenomena such as frontogenesis or turbulence cascades should be treatedwith caution. Finally, we note that the simple illustrative example in Section 2 describes the time dependenceof an exact solution of the viscous, conducting quasigeostrophic

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Russ E. Davis

principalestimator patterns. Statistical predictors of autumn and winter SLP anomalies, developed on a 20-yeardependent data set, are found to be useful in forecasting a period of I0 other years.1. Introduction In a recent paper (Davis, 1976; hereafter referredto as D1) the relationship between large-scaleanomalies of sea surface temperature (SST) andsea level pressure (SLP) was investigated using as ananalysis tool linear statistical estimators. The objective of that study was determination of how

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Robert C. Landis

form and it willbe used for future quantitative analyses. The presentearly analysis will serve to aid in designing morequantitative techniques. The radio message data takenat the close of the experiment on 28 July 1969 (Fig. 2)indicates that the Amazon water mass is much largerin extent and moves considerably more northwardthan cited by Ryther et al. (1967) and Wust (1964).Although this analysis (Fig. 2) does show the Amazonwater mass as one large tongue, time-series data at thefixed ship positions

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Antonio Espejo, Paula Camus, Iñigo J. Losada, and Fernando J. Méndez

Pacific. Our proposed analysis relies on the directional wave records of two buoys in the eastern NA ( Fig. 1 ) that are the target points for most of the wave energy propagating from west to east in this basin. As these records are not long enough to correctly capture the whole wave climate variability (less than 10 years), we combine clustering techniques looking for recurrent measured wave spectrum types (ST) and circulation types (CT) from the Climate Forecast System Reanalysis (CFSR; Saha et al

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W. C. Thacker

depth is variable. Although the finite-element results are better whencompared with finite-difference results from the same grid, comparable finite-difference results can be obtained using a finer grid at less computational expense.1. Introduction Calculation of nearshore circulation and watersurface elevation as required for forecasting stormsurges in bays and estuaries is made difficult bythe curvature of the shoreline. Finite-element techniques (Taylor and Davis, 1975; King et al., 1975;Wang

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Pierre-Marie Poulain

interpolated at 6-hour intervals using the kriging technique(Pazos 1988; Hansen and Herman 1989). Velocitieswere estimated by centered finite differences of the interpolated positions. All drogued data from February1979 until December 1990 in the eastern 'tropical Pacific were considered. No discrimination based on thedrifter or drogue type was made. Mean Eulerian velocity in a given region and for agiven time interval was generally obtained by averagingall the interpolated velocities within the

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Ole Martin Smedstad and Daniel N. Fox

307is used to infer the lower-layer pressure of a two-layerPE model. Long model simulations were used to derivestatistical relationships between the subthermoclinepressure at each point in the model and the surfacepressure at an array of grid points. This technique hasbeen successfully used to initialize the model withoceanic data and has been shown to significantly improve the forecast skill of the model (Fox et al.1992a,b). Mellor and Ezer (1991) used a technique,in which model fields were used

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