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Richard L. Temkin and Fred M. Snell

approximation for the visible spectrum, using the appropriate annual averaged solar zenith anglesand the Rodgers emissivity technique for the infrared. Ozone, above the troposphere, is assumed to actonly as an absorber in the visible. In the infrared it is assumed to have a constant hemispherical emissivityat the "tropopause" temperature (212 K). Surface reflectivities in terms of land and ocean are zonally setand land snow and ocean ice lines are calculated to occur at 273 and 263 K at sea level

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David A. Randall, James A. Abeles, and Thomas G. Corsetti

compon.ents, thesurface pressure, the PBL depth, and the groundtemperature and snow depth at land and sea icepo![nts. The governing equations are finite-differenced,using highly conservative schemes (Arakawa andLamb, 1977, 1981; Arakawa and Suarez, 1983). Them~tss flux and pressure gradient vectors are Fourierfiltered to maintain computational Stability near theI APRIL 1985 RANDALL, ABELES AND CORSETTI

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Mirjana Sakradzija and Cathy Hohenegger

form and a characteristic scale. We use LES of shallow cumulus convection based on two measurement campaigns, Rain in Cumulus over the Ocean (RICO) to represent conditions over the ocean and measurements in an Atmospheric Radiative Measurement (ARM) site to represent conditions over land ( section 2 ). We aim to reveal what makes the difference in p ( m ) between these two reference cases and to derive a parameterization for the distribution parameters that applies to oceanic and land conditions

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Patrick C. Taylor

important for understanding climate. Initial interest in the outgoing longwave radiation (OLR) diurnal cycle stemmed from attempts to determine the Earth energy budget from sun-synchronous satellite measurements ( Raschke and Bandeen 1970 ). Raschke and Bandeen (1970) present the first indications of OLR diurnal cycle characteristics using noon-minus-midnight differences, identifying large OLR diurnal cycles over land in desert and convective regions. Short and Wallace (1980) also used day

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Y. Limaitre and P. Brovelli

physicalcharacteristics of the frontal region (baroclinity, groundfriction effects, vertical stability, orientation of the LLJwith respect to the frontal discontinuity) should be developed in the framework of the Mesoscale FrontalDynamics Experiment FRONTS 87 (Browning et al.1986). Relevant data will be used in order to serve asinput for modeling purposes. Acknowledgments. The LANDES-FRONTS 84 experiment is the result of a cooperative work involving several French laboratories. The Etablissementd'Etudes et de

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M. Piper and Julie K. Lundquist

turbulence measurements in the unstable surface layer over land. J. Atmos. Sci , 34 , 515 – 530 . Chapman , D. , and K. A. Browning , 2001 : Measurements of dissipation rate in frontal zones. Quart. J. Roy. Meteor. Soc , 127 , 1939 – 1959 . Comte-Bellot , G. , and S. Corrsin , 1965 : The use of a contraction to improve the isotropy of grid-generated turbulence. J. Fluid Mech , 25 , 657 – 682 . Dhruva , B. , Y. Tsuji , and K. R. Sreenivasan , 1997 : Transverse structure

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A. Khain, N. Cohen, B. Lynn, and A. Pokrovsky

Mission (TRMM) spacecraft is shown in Fig. 4 . One can see that TC circulation penetrates far into the land even when the TC center is located several hundred kilometers from the coastline, which means that TCs approaching the land incoroporate a lot of continental aerosols into their circulation. This assumption will be tested using a numerical model. We will also show that these aerosols can lead to the formation of a narrow ring with a radius of 250–300 km and a high lightning flash density

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Shian-Jiann Lin and Raymond T. Pierrehumbert

pseudospeotral method using rational Chebyshevexpansions in both vertical and mefidional directions. It is concluded that the inslability can be eliminated onlyby the combination of strong Ekman friction with weak large-scale wind shear. Estimates of Ekman frictionbased on a realistic boundary-layer model indicate that such conditions can prevail over land when the boundarylayer is neutrally stratified. For values of Ekman friction appropriate to the open ocean, friction can reduce thegrowth rate of the most

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Jian-Ping Huang and Gerald R. North

, etc.), most climate fluctuations may be modeled as cyclostationary processes since theirproperties are modulated by these cycles. Difficulties in using conventional spectral analysis to explore theseasonal variation of climate fluctuations have indicated the need for some new statistical techniques. It issuggested here that the cyclic spectral analysis be used for interpreting such fluctuations. The technique is adaptedfrom cyclostationarity theory in signal processing. To demonstrate the

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Jean-Christophe Golaz, Vincent E. Larson, and William R. Cotton

1. Introduction In a companion paper ( Golaz et al. 2002 , hereafter Part I), we described a new boundary layer cloud single-column model (SCM). The model represents the subgrid-scale variability of vertical velocity, temperature, and moisture by use of a joint probability density function (PDF). The PDF is selected from a predetermined family for each grid box and time step, thereby allowing the PDF to vary in space and evolve in time. The family of PDFs employed is the three

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