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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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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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Chunmei Zhu, Tereza Cavazos, and Dennis P. Lettenmaier

affects the variability of monsoon onset and strength. We also confirmed that the monsoon driving force concept based on land–sea temperature contrasts is linked to the monsoon onset in MSa. We found that the most important factor driving the monsoon onset is the thermal contrast between SW and NW Mexico and the adjacent ocean conditions with early (late) monsoons initiated by a stronger (weaker) land–sea thermal contrast. Our analysis suggests that the SST ENSO-related links to the monsoon onset vary

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Wayne Higgins and David Gochis

data, including all soundings at the highest vertical resolution, and all soundings interpolated to 5-hPa levels. Several other NAME value-added data products have been delivered or are forthcoming, including radar composites, NAME atmospheric analyses, merged rain gauge datasets, merged atmospheric sounding composites, multisensor sea surface temperature products, and land surface datasets. Many of these datasets will provide essential initialization, forcing, and validation data for future NAME

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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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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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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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Arthur V. Douglas and Phillip J. Englehart

monsoon season in northern Mexico. Principal investigators and forecasters associated with the field experiment agreed that the synoptic features and event phenomena given in Table 1 would be of primary concern during the decision-making process for calling IOPs. With very detailed measurements of these systems and specific phenomena, NAME expects to develop a better understanding of the various components of the monsoon system, ranging from the diurnal cycle to large-scale forcing. This note

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Katrina Grantz, Balaji Rajagopalan, Martyn Clark, and Edith Zagona

. The resulting delayed and decreased warming of the North American landmass upsets the land–ocean heating contrasts necessary for monsoonal circulation patterns, thus delaying and decreasing the intensity of the NAMS. The relationship between antecedent land conditions and monsoonal precipitation, however, appears to vary spatially and temporally ( Lo and Clark 2002 ; Zhu et al. 2005 ), and the intensity of the monsoon may depend more on large-scale forcings than local antecedent soil moisture

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