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Rob Stoll and Fernando Porté-Agel

surface heterogeneity effects have either focused on the structure of stable internal boundary layers (e.g., Smedman et al. 1997 ; Mahrt et al. 2004 ; Skyllingstad et al. 2005 , 2007 ) or used numerical mesoscale simulations to look at surface heterogeneity in the SBL at scales on the order of 100 km ( Mahrt 1987 ; McCabe and Brown 2007 ). In a related study, Acevedo and Fitzjarrald (2001) used the large-eddy simulation technique to examine the significance of heterogeneous topography on the

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T. Sakazaki and K. Hamilton

. Wang , and S.-P. Xie , 2004 : Effects of the Andes on eastern Pacific climate: A regional atmospheric model study . J. Climate , 17 , 589 – 602 , doi: 10.1175/1520-0442(2004)017<0589:EOTAOE>2.0.CO;2 . 10.1175/1520-0442(2004)017<0589:EOTAOE>2.0.CO;2 Yagai , I. , 1989 : Nonmigrating thermal tides detected in data analysis and a general circulation model simulation . J. Geophys. Res. , 94 , 6341 – 6356 , doi: 10.1029/JD094iD05p06341 . 10.1029/JD094iD05p06341 Zeng , X. , and A

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R. A. Hansell, S. C. Tsay, Q. Ji, N. C. Hsu, M. J. Jeong, S. H. Wang, J. S. Reid, K. N. Liou, and S. C. Ou

important implications for their potential to modulate the heat and moisture surface budgets ( Solomon et al. 2007 ), surface–air exchange processes, and the general circulation of the atmosphere (e.g., Lau et al. 2006 ). It is necessary to understand these regional effects before a comprehensive understanding of its global-scale impact can be achieved. In this paper, the DRE LW of airborne mineral dust during the NASA African Monsoon Multidisciplinary Analysis (NAMMA) 2006 field campaign is

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Anupam Hazra, B. N. Goswami, and Jen-Ping Chen

present study, we propose a hypothesis regarding how invigoration takes place in BFA and not in BNFA in the background of large-scale monsoon environment and demonstrate the veracity of the hypothesis using a series of experiments with a high-resolution regional climate model. The hypothesis is illustrated in the schematic Fig. 1 . We recognize that all breaks are generally dry. However, higher concentration of aerosols make the environment dirty during BFA cases while lesser aerosol concentrations

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Olga Henneberg, Jan Henneberger, and Ulrike Lohmann

microphysics to synoptic forcing contributes to the occurrence of MPCs. In the present study we simulate MPCs in realistic orographic complex terrain in order to account for the complex Alpine orography and we modify the orography to highlight the importance of the distinct orography for the steady occurrence of MPCs at JFJ. 2. Model description and validation a. COSMO simulations Simulations are conducted with the regional weather and climate model Consortium of Small-Scale Modeling (COSMO) using a

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Adam V. Rydbeck, Eric D. Maloney, and Ghassan J. Alaka Jr.

regional model to show that convection is initiated in this region when temperature anomalies associated with westward-propagating gravity waves cool a warm capping layer near 850 hPa, allowing the convective available potential energy of the column to be realized. The gravity waves and attendant convection were found to be strongly dependent on the presence of the Andes Mountains in Colombia. The westward-propagating mesoscale convective systems in the Panama Bight ceased when the mountains were

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Hirohiko Masunaga

possibility that neighboring ridges of the interrupted Kelvin wave as a whole could account for the slow eastward propagation of the MJO. The analysis of Masunaga et al. (2006) , however, is limited to subjective diagnosis based on 10 MJO episodes. In this work, long-term outgoing longwave radiation (OLR) data are analyzed to seek climatological evidence (or its absence) of the Kelvin and ER waves as a driver of MJO propagation. Seasonality and regionality of the MJO, which were outside the scope of

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Jian-Hua Qian, Andrew W. Robertson, and Vincent Moron

pattern (not shown). This result is consistent with previous studies suggesting that the impact of La Niña is usually less significant than that of El Niño ( Hoerling et al. 1997 ; Kumar and Hoerling 1998 ). To demonstrate that the dipole pattern is indeed the result of mountain effects, we compare the control run with a regional model simulation in which the mountains are totally removed and replaced by a flat plain. Figures 6c and 6d are results of the flat-island run during SON and DJF

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S. B. Trier, C. A. Davis, and D. A. Ahijevych

.g., Tuttle and Davis 2006 ) indicate that warm-season nocturnal convection is often confined to narrow (<5°) latitudinal corridors and is strongly influenced by meridionally varying features such as quasi-stationary surface fronts and the nocturnal low-level jet (LLJ). Tuttle and Davis found that corridor events, consisting of a series of mesoscale convective systems (MCSs), typically persist for 2–7 days, and sometimes for more than 10. This longevity underscores their importance to the regional

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Stephen H. Schneider, Warren M. Washington, and Robert M. Chervin

VOL. 35, NO. 12 JOI) RNAL OF THE ATMOSPHERIC SCIENCES DECEMBER 1978Cloudiness as a Climatic Feedback Mechanism: Effects on CloudAmounts of Prescribed Global and Regional Surface Temperature Changes in the NCAR GCMSTEPI-I~N H. SCHNEIDER, WARREN M. WASHINGTON AND ROBERT M. C~ERVINNational Center for Atmospheric Research,' Boulder, CO 80307(Manuscript received 6 June 1978, in final form 29 August 1978)ABSTRACT In a

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