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M. Segal, M. J. Mitchell, and R. W. Arritt

supportive of the potential for development of local deep convection, as itcontributes to increased surface evaporation. In contrast, the larger increase in the air temperature corn * Current Affiliation: Department of Agronomy, Iowa State University, Ames, Iowa. ** Current Affiliation: National Weather Service, Minneapolis,Minnesota. Corresponding author address.' Moti Segal, Department of Agronomy, Iowa State University, Ames, IA 50011.© 1994 American Meteorological Societypared with SST

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Wouter Greuell, Erik van Meijgaard, Nicolas Clerbaux, and Jan Fokke Meirink

climate models. First, a Regional Climate Model (RCM) forced at the lateral boundaries by observations or pseudoobservations [e.g., the European Centre for Medium-Range Weather Forecasts (ECMWF) reanalyses as in this work] is more suitable for this purpose than a GCM. As a result of such forcing, differences between simulated and observed large-scale dynamics are relatively small. Hence, the largest part of the model–data differences can be ascribed to shortcomings in the physical components of the

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Melanie A. Wetzel and Gary T. Bates

and hence did not allow evaluation oflonger timescale climate parameters. Once the feasibility of nesting the RegCMI in theCCM had been demonstrated, it was necessary to evaluate these simulations over longer time periods. Giorgiand Bates (1989) conducted monthlong simulationsof January 1979 with the model boundary conditionsdriven not by the CCM, but by the European Centrefor Medium-Range Weather Forecasts (ECMWF)analyses of atmospheric observations, so that biasesdue to the regional model

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Yongkang Xue and Jagadish Shukla

from being applied (Glantz 1977).Another plan, which involved planting a forest belt inWest Africa to combat desertification, was proposed byStebbing (1938). He expected this belt to stop thesands from moving southward, break up. the northeasthot dry wind, and encourage moisture retention in thesoil. Before the 1970s, this plan was not considered asa weather and climate modification scheme because amajority of scientists believed that in arid zones afforestation could not have any significant

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Paul E. Roundy, Kyle MacRitchie, Jonas Asuma, and Timothy Melino

1. Introduction Prediction of midlatitude weather at lead times longer than four or five days depends on the geographical distribution and temporal evolution of moist deep convection in the tropics ( Wallace and Gutzler 1981 ; Ferranti et al. 1990 ; Weickmann et al. 1997 ; Mo and Higgins 1998 ; Hendon et al. 2000 ; Higgins et al. 2000 ; Jones and Schemm 2000 ; Nogues-Paegle et al. 2000 ; Mo 2000 ; Branstator 2002 ; Jones et al. 2004a , b ; Weickmann and Berry 2007 ). This dependence

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Jinghua Chen, Xiaoqing Wu, Yan Yin, Qian Huang, and Hui Xiao

), and partly by the U.S. National Science Foundation under Grant ATM-0935263 (Wu). REFERENCES Bao , X. , and F. Zhang , 2013 : Evaluation of NCEP–CFSR, NCEP–NCAR, ERA-Interim, and ERA-40 reanalysis datasets against independent sounding observations over the Tibetan Plateau . J. Climate , 26 , 206 – 214 , doi: 10.1175/JCLI-D-12-00056.1 . 10.1175/JCLI-D-12-00056.1 Berry , E. X. , 1968 : Modification of the warm rain process. Proc. First Conf. on Weather Modification , Albany, NY, Amer

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Andrew Rhines and Peter J. Huybers

overestimated relative to other models and observations ( Pan et al. 2010 ). The wet bias has been traced to an interaction between cooling via cloud radiative forcing and excess diabatic heating. Studies of synoptic activity nevertheless show that the frequency of a given synoptic pattern is well simulated ( Schuenemann and Cassano 2009 ), implying that each weather system type systematically produces too much precipitation and suggesting that the model is suitable for our purposes of exploring relative

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B. C. Hewitson and R. G. Crane

representivity that is likely to be both directionally dependent and conditional on the prevailing weather system. Conceptually, the information content of point data with respect to the magnitude and variance reflects some variable mix of forcing, comprised of local forcing (such as vegetation state or soil moisture) and the larger-scale synoptic forcing (e.g., frontal conditions or convective states). The ratio of the local to synoptic forcing that underlies the measured point data is unknown, and is

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Stanley S. Jacobs and Josefino C. Comiso

the Special Sensor Microwave Imagers (SSMI; 1987–94) of the Defense Meteorological Satellite Program. To fill gaps in these records during the 1970s, we used information derived from National Ice Center (NIC) charts, compiled from visible, thermal infrared, and passive microwave observations ( NOCDA 1985 ). Weatherly et al. (1991) found no systematic difference between NIC and ESMR ice extents, but noted a slight negative bias relative to the SMMR records of Gloersen et al. (1992) . During 6

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T. Jung, M. J. Miller, T. N. Palmer, P. Towers, N. Wedi, D. Achuthavarier, J. M. Adams, E. L. Altshuler, B. A. Cash, J. L. Kinter III, L. Marx, C. Stan, and K. I. Hodges

provided climate scientists from four centers, namely the Center for Ocean–Land–Atmosphere Studies (COLA), the European Centre for Medium-Range Weather Forecasts (ECMWF), the University of Tokyo, and the Japan Agency for Marine–Earth Science and Technology (JAMSTEC), dedicated access for a 6-month period starting on 1 October 2009 to Athena, a 166-teraflop Cray XT4 system located at the National Institute for Computational Sciences (NICS) in Tennessee, hence, the name Project Athena (Kinter et al. 2011

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