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Paquita Zuidema, Chris Fairall, Leslie M. Hartten, Jeffrey E. Hare, and Daniel Wolfe

Marinone (2003) . On a few occasions (13 and 14 July, and 4 August), the net flux was almost at or below zero, indicating high daytime cloud cover. Apparent from the solar flux values, leg 1 was generally cloudier during the day, while leg 2 contained more daytime cloudiness variability, with both more clear and more deeply cloudy conditions. The impact of clouds on the surface energy budget is best indicated by the cloud forcing, or the difference in the observed mean radiative flux from the clear

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Mekonnen Gebremichael, Enrique R. Vivoni, Christopher J. Watts, and Julio C. Rodríguez

semiarid areas, which are generally characterized by low annual rainfall and large interannual variability. The large-scale variability of monsoon rainfall and its relationship to teleconnective, and synoptic- and mesoscale forcing mechanisms has been a focus of many studies (e.g., Douglas et al. 1993 ; Adams and Comrie 1997 ; Higgins and Shi 2001 ). However, work on the submesoscale (<75 km) variability of rainfall is noticeably absent in the literature, mainly due to a paucity of ground

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Chunmei Zhu and Dennis P. Lettenmaier

climatological forcing dataset for land surface models (including precipitation, and daily maximum and minimum temperatures) over Mexico because of quality control problems, as well as discontinuity and unavailability of raw station data. Some datasets that have recently become available help to alleviate this problem though. Recently (in 2005), the Servicio Meteorológico Nacional of Mexico (SMN) released a long-term improved surface station dataset that includes precipitation, and daily maximum and minimum

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

the southwestern United States and northern Mexico, the 2004 NAM results are examined in diagnoses 3–5 above. It is well known that the results of a regional climate model can be affected by many factors, including the selection of the modeling configurations, boundary forcing, initialization data, and methods. One decision that must be made for modeling the 2004 NAM is how frequently the model run should be adjusted (by reinitialization or nudging methods) using observation data assimilations to

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Wanqiu Wang and Pingping Xie

-orbiting National Oceanic and Atmospheric Administration (NOAA) satellites ( May et al. 1998 ). While the weekly OI and daily RTG SST analyses have been applied successfully in monitoring weather/climate and forcing numerical models as boundary conditions for weather/climate simulation and prediction, further desirable improvements in their quantitatively accuracy and time–space resolution are limited largely due to the infrequent sampling of polar-orbiting NOAA satellites and the inability of the AVHRR

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Myong-In Lee, Siegfried D. Schubert, Max J. Suarez, Isaac M. Held, Arun Kumar, Thomas L. Bell, Jae-Kyung E. Schemm, Ngar-Cheung Lau, Jeffrey J. Ploshay, Hyun-Kyung Kim, and Soo-Hyun Yoo

boundary forcing (i.e., orography and land–sea contrast) in global climate models that are typically run at a horizontal resolution of several hundred kilometers, as well as limitations in the parameterization of moist convection ( Dai et al. 1999 ; Zhang 2003 ; Liang et al. 2004 ; Lee et al. 2007 ). While the diurnal cycle of atmospheric convection over the continents is largely controlled by the direct thermodynamic response to insolation and surface heating, there are nevertheless large

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J. Craig Collier and Guang J. Zhang

intensification of an anticyclonic gyre is a major forcing mechanism for the low-level monsoon moisture-laden circulation over western Mexico. And the monsoon is more than just a hydrologic forcing on the climate system. Barlow et al. (1998) show that in the monsoon’s mature phase diabatic heating over northwestern Mexico is as large as 1 K day −1 , which influences continental-scale divergence and vorticity dynamics. Accurately predicting the interannual variability of the monsoon system would aid water

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Timothy J. Lang, David A. Ahijevych, Stephen W. Nesbitt, Richard E. Carbone, Steven A. Rutledge, and Robert Cifelli

, which then force gulf convection later (e.g., Mapes et al. 2003 ). This study will establish the timing, evolution, and propagation of convective systems, thus testing both of these hypotheses. b. Intraseasonal variability of precipitation A major goal of NAME is to better understand regimes associated with intraseasonal variability of convection during July–August in the tier I region and its linkages to precipitation in the southwestern United States, including the influences of surges, jets

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Kingtse C. Mo, Eric Rogers, Wesley Ebisuzaki, R. Wayne Higgins, J. Woollen, and M. L. Carrera

Mesinger et al. (2006) and Shafran et al. (2004) . The RCDAS has the NCEP–Oregon State University–U.S. Air Force–NWS/Hydrologic Research Lab (Noah) land surface model as a subcomponent ( Mitchell et al. 2004 ). The RCDAS assimilates precipitation ( P ) ( Lin et al. 2001 ). The input P data include the Climate Prediction Center (CPC) operational rain gauge precipitation over the United States and Mexico ( Higgins et al. 2000 ) and the CPC Morphing technique (CMORPH) data ( Joyce et al. 2004 ). The

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Christopher J. Watts, Russell L. Scott, Jaime Garatuza-Payan, Julio C. Rodriguez, John H. Prueger, William P. Kustas, and Michael Douglas

than the other components and may be neglected. In this case we may use the energy balance to write If there is closure in the energy balance, the two expressions for EF [Eqs. (6) and (7) ] are exactly equal. In practice, it is common that the energy balance does not close ( Twine et al. 2000 ) so that each expression gives slightly different results. We can see that the EF is normalized ET with respect to differences in net radiation. It is also much less noisy than ET since clouds will tend

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