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Hyun Mee Kim and Byoung-Joo Jung

) used in Kim and Jung (2009) . Section 2 describes the experimental framework. The results are presented in section 3 . Section 4 contains a summary and discussion. 2. Experimental framework a. Model and physical processes This study uses the fifth-generation Pennsylvania State University–National Center for Atmospheric Research Mesoscale Model (MM5), together with the MM5 adjoint modeling system ( Zou et al. 1997 ) and a Lanczos algorithm, to calculate SVs. The model domain for this study is

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Hyun Mee Kim and Byoung-Joo Jung

reduced to an ordinary eigenvalue problem by multiplying both sides of (3) with the inverse of the square root of 𝗖. Then a Lanczos-type algorithm (e.g., Ehrendorfer and Errico 1995 ; Kim 2003 ; Kim et al. 2004 ) is used to solve for x′ (0) in (3) . To investigate the effect of different norms on the growth and structure of SVs, dry and moist TE norms were used. The dry TE is defined according to Zou et al. (1997) as where E d is the dry TE in a nonhydrostatic model; u ′, υ ′, and w

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Mark Buehner, P. L. Houtekamer, Cecilien Charette, Herschel L. Mitchell, and Bin He

study are given. Section 3 highlights differences in the two approaches related to the use of a single “deterministic” analysis versus an ensemble of analyses. In section 4 differences in the solution algorithm used for each are considered. Differences due to the application of spatial localization to ensemble background-error covariances are discussed in section 5 . In section 6 differences in the various approaches with respect to the temporal evolution of the background-error covariances

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Matthieu Plu

, the mean distance E j , k between j Δ t hours and k Δ t hours forecasts is given by the formula: where M i , l is the cyclone position in the l Δ t hours model forecast valid at instant i , N j , k is the number of forecasts, and d ( , ) is the distance along the earth’s great circle ( Bengtsson et al. 2005 ). Cyclone positions in the forecasts are computed using a simple and robust tracking algorithm ( appendix A ). The time step Δ t is 12 h. Like in many predictability studies

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Mu Mu, Feifan Zhou, and Hongli Wang

. According to Barkmeijer et al. (2003) , the first singular value σ 1 of 𝗟 satisfies the following (with respect to the norms 𝗖 1 and 𝗖 2 ): Additionally, if v 1 is the first singular vector of 𝗟, then where superscript −1 denotes the inverse of the matrix. In this paper, we will numerically solve the following nonlinear optimization problem to obtain the FSV: where Thus, both CNOP and FSV can be obtained by using the same optimization algorithm to facilitate comparison, and for further

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Sim D. Aberson

time of each mission was used. During the 10 yr, several major upgrades to the quality control algorithm, the tropical cyclone vortex initialization procedure, the data assimilation, and the Global Spectral Model were made. The quality control algorithm involves optimal interpolation and hierarchical decision making to evaluate the observations before input to the analysis ( Woollen 1991 ). Until 2000, the synthetic data procedure ( Lord 1991 ) created observations representative of the tropical

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Peter Black, Lee Harrison, Mark Beaubien, Robert Bluth, Roy Woods, Andrew Penny, Robert W. Smith, and James D. Doyle

filtering. This technology becomes important at high altitudes (>18 km), where line-of-sight transmission pathlengths from aircraft to sonde can be >200 km from WB-57 or DC-8 flights. FEC algorithms such as Viterbi ( Gupta et al. 2010 ) use additional bandwidth to send along specially encoded extra data bits with the data payload. At the telemetry receiver, a mathematical decode algorithm reconstructs the dataset from a corrupted packet using the extra FEC data. The first XDD system tested at CIRPAS had

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Kun-Hsuan Chou, Chun-Chieh Wu, Po-Hsiung Lin, Sim D. Aberson, Martin Weissmann, Florian Harnisch, and Tetsuo Nakazawa

Global Data Assimilation System uses a quality control algorithm, a TC vortex relocation procedure, and the Global Spectral Model. The quality control involves optimal interpolation and hierarchical decision making to evaluate the observations before going into detailed analysis ( Woollen 1991 ). A vortex relocation procedure ( Liu et al. 2000 ) in which TCs in the first guess field are relocated to the analyzed position in each 6-h analysis cycle (as in Kurihara et al. 1995 ) ensures that the

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Sim D. Aberson

reports from the National Hurricane Center (NHC) and the Joint Typhoon Warning Center (JTWC). The environments of three tropical cyclones in the Atlantic and four in the west Pacific were sampled with aircraft 2 ( Fig. 1 ). NHC and JTWC best tracks are used for forecast verification. The GFS version operational during September 2008 was used to assess the dropwindsonde data impact on forecasts. The system consisted of a quality control algorithm, a tropical cyclone vortex initialization procedure, a

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