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Junshi Ito, Hiroshige Tsuguchi, Syugo Hayashi, and Hiroshi Niino

cooling was switched off. Although it is generally considered that quasi-stationary QLCSs may be caused by larger-scale forcing such as a mesoscale convective vortex (e.g., Unuma and Takemi 2016 ), such forcing was absent in the KH2017 case. The present study explores the causes of such a QLCS by means of idealized numerical simulations with a simplified configuration. We consider a zonally uniform belt of flat land sandwiched by seas to the north and south. In fact, surface temperature contrasts

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Quanxin Xia, Ching-Long Lin, Ronald Calhoun, and Rob K. Newsom

atmospheric variables to provide some critical information about the ABL dynamics ( Banta et al. 1996 , 2004 ). These measurements, however, scatter in space and time. Integration of the information to provide a more complete picture of the atmospheric state is highly desirable. Thus, if data from active remote sensors is used to drive a numerical prediction model, the model can be used to derive the atmospheric conditions that were necessary to create the observed phenomena. In this way, we achieve a

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Qingfang Jiang, Qing Wang, Shouping Wang, and Saša Gaberšek

1. Introduction Monin–Obukhov similarity theory (MOST) is widely used in numerical weather prediction models to provide lower boundary conditions, and in radio wave propagation models to characterize the atmospheric environment in the marine surface layer. While MOST has been extensively tested with field observations over relatively homogeneous land surfaces (e.g., Businger et al. 1971 ; Dyer 1974 ; Foken and Skeib 1983 ), its validity over ocean remains an open question. The similarity

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Anna Trevisan and Francesco Uboldi

the ocean is sufficient to reduce both the analysis and forecast error to such an extent to make it comparable to the error over land. The success of the experiment is particularly encouraging in view of the fact that we have used a single observation and a single assimilating vector, and one can expect that the error will be further reduced if a larger number of vectors and observations is used. On the other hand, if assimilations are made at relatively short time intervals, the various unstable

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R. A. J. Neggers, P. J. Griewank, and T. Heus

problem. A natural way of characterizing the scale dependence within a cumulus population is the size distribution of a cloud field, which has been scientifically established for many cloud regimes using a large variety of instrumentation (e.g., Plank 1969 ; Raga et al. 1990 ; Benner and Curry 1998 ; Zhao and Di Girolamo 2007 ; Yuan 2011 ) and finescale cloud-resolving simulation (e.g., Neggers et al. 2003 ; Rieck et al. 2014 ; Senf et al. 2018 ). A characteristic feature of the size density

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Roni Avissar and Tatyana Schmidt

the boundary layer. Young (1988) compared the profiles of turbulence statistics obtained from observations and numerical studies in rolling and flat terrain. He found no significant difference between the turbulence structure obtained in a terrain with topographical features on the order of 100 m as compared to a more uniform terrain. Finally, Avissar et al. (1998) used RAMS–LES to simulate the CBL that developed in the First International Satellite Land Surface Climatology Project (ISLSCP

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M. Kanakidou, S. Myriokefalitakis, N. Daskalakis, G. Fanourgakis, A. Nenes, A. R. Baker, K. Tsigaridis, and N. Mihalopoulos

(except for a few locations over the eastern United States, southern India, the Bengal Bay, the Arabian Sea, and southeastern Australia, where significant land-use changes have occurred) and is expected to further increase over densely populated regions ( Fig. 4d ). Large increases have occurred over the heavily industrialized areas of the Northern Hemisphere for all soluble reactive N fractions as depicted in Figs. 4a–c and are projected to occur in the future mainly in Asia ( Figs. 4b–f ), while

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Robert C. Malone, Eric J. Pitcher, Maurice L. Blackmon, Kamal Puri, and William Bourke

possesses a realistic distribution of continents and oceansand realistic, but smoothed, topography. Two simulations with perpetual January and July forcing by climatological sea surface temperatures, sea ice, and insolation were extended to 1200 days, of which the final600 days were used for the results in this study. We find that the stationary waves are well simulated in both seasons in the Northern Hemisphere, wherestrong forcing by orography and !and-sea thermal contrasts exists. However, in the

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Yizhak Feliks

scale height of the atmosphere. This allows us to use the Boussinesq incompressible approximation of the equations of motion. We utilize a two-dimensional numerical model of Feliks (1993) to study the sea and land breeze in a vertical cross section perpendicular to the sea shore, where x < 0 is the sea and x > 0 is the land. We did some modification in the numerical schemes particularly in the horizontal advection terms. a. Model equations The horizontal components of the equations of motion

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Yunyan Zhang and Stephen A. Klein

use convective-regime-oriented composites from long-term observations over land to make a systematic assessment of these transition mechanisms. The Atmospheric Radiation Measurement (ARM; Strokes and Schwatz 1994 ; Ackerman and Stokes 2003 ) Climate Research Facility provides the necessary long-term comprehensive measurements at its Southern Great Plains (SGP) site. However, the coexistence of multiple convection regimes at various temporal and spatial scales complicates the analysis of SGP

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