The authors are grateful to Greg Hakim and two anonymous reviewers for their comments, which helped improve the manuscript. Sharanya Majumdar and Kathryn Sellwood gratefully acknowledge funding by NOAA THORPEX. Daniel Hodyss was sponsored by a postdoctoral fellowship at the University of Miami’s Rosenstiel School of Marine and Atmospheric Science, and the Naval Research Laboratory and the Office of Naval Research under Program Element 0601153N. The authors are also grateful to the National Centers for Environmental Prediction for provision of the ensemble data and supercomputer time, and to Craig Bishop and Istvan Szunyogh for helpful discussions. Carolyn Reynolds and Justin McLay of the Naval Research Laboratory, Monterey, California, provided the NAVDAS estimates of analysis error variance.
Aberson, S. D., 2003: Targeted observations to improve operational tropical cyclone track forecast guidance. Mon. Wea. Rev., 131 , 1613–1628.
Ancell, B., and G. J. Hakim, 2007: Comparing adjoint- and ensemble-sensitivity analysis with applications to observation targeting. Mon. Wea. Rev., 135 , 4117–4134.
Bishop, C. H., B. J. Etherton, and S. J. Majumdar, 2001: Adaptive sampling with the ensemble transform Kalman filter. Part I: Theoretical aspects. Mon. Wea. Rev., 129 , 420–436.
Bishop, C. H., B. J. Etherton, and S. J. Majumdar, 2006: Verification region selection and data assimilation for adaptive sampling. Quart. J. Roy. Meteor. Soc., 132 , 915–933.
Buizza, R., and T. Palmer, 1995: The singular-vector structure of the atmospheric global circulation. J. Atmos. Sci., 52 , 1434–1456.
Buizza, R., D. S. Richardson, and T. N. Palmer, 2003: Benefits of increased resolution in the ECMWF ensemble system and comparison with poor-man’s ensembles. Quart. J. Roy. Meteor. Soc., 129 , 1269–1288.
Buizza, R., C. Cardinali, G. Kelly, and J-N. Thépaut, 2007: The value of targeted observations. Part II: The value of observations taken in singular vectors-based target areas. Quart. J. Roy. Meteor. Soc., 133 , 1817–1832.
Chang, E. K. M., 1993: Downstream development of baroclinic waves as inferred from regression analysis. J. Atmos. Sci., 50 , 2038–2053.
Chang, E. K. M., and I. Orlanski, 1994: On energy flux and group velocity of waves in baroclinic flows. J. Atmos. Sci., 51 , 3823–3828.
Danielson, R. E., J. R. Gyakum, and D. N. Straub, 2004: Downstream baroclinic development among forty-one cold-season eastern North Pacific cyclones. Atmos.–Ocean, 42 , 235–250.
Draxler, R. R., and G. D. Rolph, cited. 2003: HYSPLIT (Hybrid Single-Particle Lagrangian Integrated Trajectory) Model. NOAA/ARL, Silver Spring, MD. [Available online at http://www.arl.noaa.gov/ready/hysplit4.html].
Gelaro, R., T. Rosmond, and R. Daley, 2002: Singular vector calculations with an analysis error variance metric. Mon. Wea. Rev., 130 , 1166–1186.
Hodyss, D., and S. J. Majumdar, 2007: The contamination of “Data Impact” in global models by rapidly growing mesoscale instabilities. Quart. J. Roy. Meteor. Soc., 133 , 1865–1875.
Kelly, G., J-N. Thépaut, R. Buizza, and C. Cardinali, 2007: The value of targeted observations. Part I: Data denial experiments for the Atlantic and the Pacific. Quart. J. Roy. Meteor. Soc., 133 , 1803–1815.
Leutbecher, M., 2003: A reduced rank estimate of forecast error variance changes due to intermittent modifications of the observing network. J. Atmos. Sci., 60 , 729–742.
Lorenz, E. N., and K. A. Emanuel, 1998: Optimal sites for supplementary weather observations: Simulation with a small model. J. Atmos. Sci., 55 , 399–414.
MacDonald, A. E., 2005: A global profiling system for improved weather and climate prediction. Bull. Amer. Meteor. Soc., 86 , 1747–1764.
Magnusson, L., M. Leutbecher, and E. Källén, 2008: Comparison between singular vectors and breeding vectors as initial perturbations for the ECMWF ensemble prediction system. Mon. Wea. Rev., 136 , 4092–4104.
Majumdar, S. J., C. H. Bishop, B. J. Etherton, I. Szunyogh, and Z. Toth, 2001: Can an ensemble transform Kalman filter predict the reduction in forecast error variance produced by targeted observations? Quart. J. Roy. Meteor. Soc., 127 , 2803–2820.
Majumdar, S. J., C. H. Bishop, B. J. Etherton, and Z. Toth, 2002: Adaptive sampling with the ensemble transform Kalman filter. Part II: Field program implementation. Mon. Wea. Rev., 130 , 1356–1369.
Majumdar, S. J., S. D. Aberson, C. H. Bishop, R. Buizza, M. S. Peng, and C. A. Reynolds, 2006: A comparison of adaptive observing guidance for Atlantic tropical cyclones. Mon. Wea. Rev., 134 , 2354–2372.
McLay, J. G., C. H. Bishop, and C. A. Reynolds, 2008: Evaluation of the ensemble transform analysis perturbation scheme at NRL. Mon. Wea. Rev., 136 , 1093–1108.
Meng, Z., and F. Zhang, 2008a: Tests of an ensemble Kalman filter for mesoscale and regional-scale data assimilation. Part III: Comparison with 3DVAR in a real-data case study. Mon. Wea. Rev., 136 , 522–540.
Meng, Z., and F. Zhang, 2008b: Tests of an ensemble Kalman filter for mesoscale and regional-scale data assimilation. Part IV: Comparison with 3DVAR in a month-long experiment. Mon. Wea. Rev., 136 , 3671–3682.
Orlanski, I., and J. Katzfey, 1991: The life cycle of a cyclone wave in the Southern Hemisphere. Part I: Eddy energy budget. J. Atmos. Sci., 48 , 1972–1998.
Orlanski, I., and E. K. M. Chang, 1993: Ageostrophic geopotential fluxes in downstream and upstream development of baroclinic waves. J. Atmos. Sci., 50 , 212–225.
Orlanski, I., and J. P. Sheldon, 1993: A case of downstream baroclinic development over western North America. Mon. Wea. Rev., 121 , 2929–2950.
Palmer, T. N., R. Gelaro, J. Barkmeijer, and R. Buizza, 1998: Singular vectors, metrics, and adaptive observations. J. Atmos. Sci., 55 , 633–653.
Pellerin, G., L. LeFaivre, P. L. Houtekamer, and C. Girard, 2003: Increasing the horizontal resolution of ensemble forecasts at CMC. Nonlinear Processes Geophys., 10 , 463–468.
Petersen, G. N., S. J. Majumdar, and A. J. Thorpe, 2007: The properties of sensitive area predictions based on the ensemble transform Kalman filter (ETKF). Quart. J. Roy. Meteor. Soc., 133 , 697–710.
Rabier, F., and Coauthors, 2008: An update on THORPEX-related research in data assimilation and observing strategies. Nonlinear Processes Geophys., 15 , 81–94.
Reynolds, C. A., and T. E. Rosmond, 2003: Nonlinear growth of singular-vector-based perturbations. Quart. J. Roy. Meteor. Soc., 129 , 3059–3078.
Reynolds, C. A., M. S. Peng, S. J. Majumdar, S. D. Aberson, C. H. Bishop, and R. Buizza, 2007: Interpretation of adaptive observing guidance for Atlantic tropical cyclones. Mon. Wea. Rev., 135 , 4006–4029.
Sellwood, K. J., S. J. Majumdar, B. E. Mapes, and I. Szunyogh, 2008: Predicting the influence of observations on medium-range forecasts of atmospheric flow. Quart. J. Roy. Meteor. Soc., 134 , 2011–2027.
Simmons, A. J., and B. J. Hoskins, 1979: The downstream and upstream development of unstable baroclinic waves. J. Atmos. Sci., 36 , 1239–1254.
Szunyogh, I., Z. Toth, A. V. Zimin, S. J. Majumdar, and A. Persson, 2002: On the propagation of the effect of targeted observations: The 2000 Winter Storm Reconnaissance Program. Mon. Wea. Rev., 130 , 2803–2820.
Szunyogh, I., E. J. Kostelich, G. Gyarmati, E. Kalnay, B. R. Hunt, E. Ott, E. Satterfield, and J. A. Yorke, 2008: A local ensemble transform Kalman filter data assimilation system for the NCEP global model. Tellus, 60 , 113–130.
Torn, R. D., and G. J. Hakim, 2008: Performance characteristics of a pseudo-operational ensemble Kalman filter. Mon. Wea. Rev., 136 , 3947–3963.
Velden, C., and Coauthors, 2005: Recent innovations in deriving tropospheric winds from meteorological satellites. Bull. Amer. Meteor. Soc., 86 , 205–223.
Wei, M., Z. Toth, R. Wobus, and Y. Zhu, 2008: Initial perturbations based on the ensemble transform (ET) technique in the NCEP global operation forecast system. Tellus, 60A , 62–79.
Weissmann, M., R. Busen, A. Dörnbrack, S. Rahm, and O. Reitebuch, 2005: Targeted observations with an airborne wind lidar. J. Atmos. Oceanic Technol., 22 , 1706–1719.
Whitaker, J. S., T. M. Hamill, X. Wei, Y. Song, and Z. Toth, 2008: Ensemble data assimilation with the NCEP Global Forecast System. Mon. Wea. Rev., 136 , 463–482.
Zhang, F., C. Snyder, and R. Rotunno, 2003: Effects of moist convection on mesoscale predictability. J. Atmos. Sci., 60 , 1173–1185.
Zhang, F., A. M. Odins, and J. W. Nielsen-Gammon, 2006: Mesoscale predictability of an extreme warm-season precipitation event. Wea. Forecasting, 21 , 149–166.
Zimin, A. V., I. Szunyogh, D. J. Patil, B. R. Hunt, and E. Ott, 2003: Extracting envelopes of Rossby wave packets. Mon. Wea. Rev., 131 , 1011–1017.