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Ana M. B. Nunes and John O. Roads

challenging problem. A more simplified approach to the precipitation assimilation (PA) in atmospheric models is to nudge latent heat rates. This procedure was used by the National Centers for Environmental Prediction (NCEP) North American Regional Reanalysis (NARR; Mesinger et al. 2006 ) to generate a realistic hydroclimatology. Similarly, Nunes and Cocke (2004) and Nunes and Roads (2005) assimilated precipitation by nudging moisture profiles, mainly because the uncertainties in the humidity fields

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Richard G. Lawford, John Roads, Dennis P. Lettenmaier, and Phillip Arkin

vegetation cover are generally much more important than the initial atmospheric conditions. The contributions of surface conditions such as surface moisture and vegetation vigor provide “memory” in the climate system that can contribute to a system’s predictability. The North American Land Data Assimilation System (NLDAS) is one approach for obtaining better surface conditions for prediction models ( Mitchell et al. 2004 ). This system uses inputs of current weather conditions as well as boundary

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J. Li, X. Gao, and S. Sorooshian

atmospheric column (i.e., convergence). 4. Evaluation of model results The model simulation’s performance was evaluated using the following observation and analysis data: 1) 25-km and daily precipitation analysis data from the National Weather Service ( ); 2) stage-IV multisource (radar mixing with gauge) 4 km × 4 km, hourly precipitation data; 3) North American Regional Reanalysis (NARR) data ( ) with 3-hourly

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Song Yang, S-H. Yoo, R. Yang, K. E. Mitchell, H. van den Dool, and R. W. Higgins

connection between summer monsoons and the preceding snow cover in Asia as well as in North America ( Hahn and Shukla 1976 ; Barnett et al. 1989 ; Meehl 1994 ; Yang et al. 1996 ; Gutzler and Preston 1997 ; Higgins et al. 1998 ; Yang and Lau 1998 ; Hu and Feng 2002 ). Even in the summer season itself, the monthly persistence of surface temperature cannot be well explained without soil–atmosphere interactions ( Huang and Van den Dool 1993 ; Huang et al. 1996 ). Previous studies have also

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Kevin E. Trenberth, Lesley Smith, Taotao Qian, Aiguo Dai, and John Fasullo

, while precipitation has increased at higher latitudes in Europe, northern Asia, North America, and South America ( Dai et al. 2004 ) in part because higher temperatures increase water-holding capacity and more precipitation falls as rain instead of snow ( Trenberth and Shea 2005 ). A longstanding challenge is to provide a reliable estimate of the annual mean global water cycle. Our latest estimate is given in Fig. 1 and, while there are large uncertainties in many of the estimated numbers

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Guoxiong Wu, Yimin Liu, Qiong Zhang, Anmin Duan, Tongmei Wang, Rijin Wan, Xin Liu, Weiping Li, Zaizhi Wang, and Xiaoyun Liang

PRES in North America. It seems that the time-lag heating mechanism could be a necessary but not a sufficient condition for the formation of PRES. As demonstrated in Fig. 7a , before the monsoon onset the TP can generate a dipole-type circulation pattern. The deflected flow brings cold, air from the north and moist, air from the south, which then converge over eastern China. This may contribute to the formation of PRES. To verify this hypothesis, a series of numerical experiments were conducted by

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Xubin Zeng and Aihui Wang

: Aerodynamic and canopy resistance of short-rotation forest in relationship to leaf area index and climate. Bound.-Layer Meteor. , 66 , 265 – 279 . 10.1007/BF00705478 Mitchell, K. , and Coauthors , 2004 : The multi-institution North American Land Data Assimilation System (NLDAS): Utilizing multiple GCIP products and partners in a continental distributed hydrological modeling system. J. Geophys. Res. , 109 . D07S90, doi:10.1029/2003JD003823 . Oleson, K. W. , and Coauthors , 2004 : Technical

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