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Richard H. Johnson

cumulus layer above.Recent findings from both aircraft measurements(LeMone and Pennell, 1976) and budget~ studies(Holland and Rasmussen, 1973; Esbensen, 1975; andothers) in the undisturbed trades indicate significantenhancement of the mixed or subcloud layer watervapor fluxes in legions occupied by cumulus cloudsover those in clear areas. During disturbed weatherconditions the effects of cumulus convection on the subcloud layer structure are even more pronounced.Marked stabilization of the lower

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David W. Behringer, Ming Ji, and Ants Leetmaa

s −1 ( Qiao and Weisburg 1997 ). These comparisons suggest that the RA6 surface currents have improved relative to the RA5 analysis. Figure 4 compares average zonal velocity profiles from RA5 and RA6 to measurements at three locations on the equator: 110°W, 140°W, and 165°E. The measurements at 110°W and 140°W were made between January 1991 and December 1994 with mechanical current meters; the measurements at 165°E were made between April 1992 and December 1994 by acoustic Doppler current

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Cornelius Hald, Matthias Zeeman, Patrick Laux, Matthias Mauder, and Harald Kunstmann

prescribed maximum. It has to be noted that the solutions of the presented runs are affected by the dependency on the acoustic and model time step as was presented by Yamaguchi and Feingold (2012) . Both model runs were initialized at 0000 UTC (0200 local time) on their respective dates. Data starting at 6 h after model initialization were deemed usable. Full 3D fields were written every 5 min. The data to be compared with the measurements are taken from profiles at four grid points in a 2 × 2 pattern

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Deborah J. Abbs and Jørgen B. Jensen

) ORGANIZATION OF THE CLOUD FIELDS' TOPOGRAPHIC ANCHORING, ADVECTION, AND TRANSIENT EFFECTS ( i ) Along-wind measurements In the following, measurements from six flight legswill be examined in order to determine if the cloudfields are 1 ) topographically anchored or 2) advectedwith the wind. The individual cloud parcels are obviously being advected along; the question here iswhether large-scale cloud fields remain stationary orwhether they are advected. Measurements from the period ! 451

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Steven E. Koch, Paul B. Dorian, R. Ferrare, S. H. Melfi, William C. Skillman, and D. Whiteman

bore. Thus, pronouncedsurface cooling is not characteristic of bores; in fact,temperature often rises as the result of turbulent downward mixing of warmer air from above the inversionin the case of bores. Previous observational studies of atmospheric gravitycurrents and bores have employed photography, surface synoptic and mesonetwork measurements, instrumented towers, pilot balloons, instrumented aircraft,acoustic sounders, satellite imagery, doppler radar, andaerosol lidars (McAllister 1968

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C. E. Skupniewicz, J. W. Glendening, and R. F. Kamada

the accuracy ofthe measurements. Edinger (1963) presented a complex picture of a sinking, then rising boundary layerout to distances of 60 km from a stratocumulus edge. This paper examines the effects of a cloud-edge transition from stratocumulus to clear sky on boundarylayer height, wind speed, wind direction, and windshear in a coastal environment. Field measurementsobtained during four case studies document commoncharacteristics of the transition. A numerical modelinterprets the features in

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Tammy M. Weckwerth, James W. Wilson, and Roger M. Wakimoto

underestimated. Perhaps with the installation of NOAA'sWind Profiler Demonstration Network, many of whichare equipped with the radio acoustic sounding system782 MONTHLY WEATHER REVIEW VOLUME 124~elative cloud bases and ~,e~,,,,s t ~ ....,,,~ ..~..,,~ >redicted from measurements/ 'X '="'.~ ....... directly beneath them

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J-L. Caccia and J-P. Cammas

Brittany coast. The lee waves induced at low altitudes are subgrid-scale effects that are not taken into account in the ECMWF T106 operational model used here. These lee waves, to which the vertical velocity measurement by VHF-ST radar is sensible, should be the main cause of disagreement between Figs. 17 and 18 below 4-km altitude. This was illustrated by a recent work ( Lott 1995 ) in which its was shown that a subgrid parameterization of the orography (which is not included in the ECMWFT106

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K. L. Echternacht and M. Garstang

AvRrt, 1976 K. L. ECHTERNACHT AND M. GARSTANG 407Changes in the Structure of the Tropical Subcloud Layer from the Undisturbed to Disturbed States K. L. ECHTERNACHT Institute for Acoustical Research, Miami, Fla. 33130 M. G~ST~.NGDepartment of Environmental Sciences, University of Virginia, Charlottesville 22903(Manuscript received 21 June 1975, in revised form 24 November

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Belay Demoz, Cyrille Flamant, Tammy Weckwerth, David Whiteman, Keith Evans, Frédéric Fabry, Paolo Di Girolamo, David Miller, Bart Geerts, William Brown, Geary Schwemmer, Bruce Gentry, Wayne Feltz, and Zhien Wang

layer variables such as moisture, wind, and temperature are important to understanding CI ( Weckwerth et al. 1996 ; Crook 1996 ; Weckwerth 2000 ). This paper focuses on the evolution and variability of the convective-scale moisture and wind in the boundary layer during a dryline event that occurred on 22 May 2002 in the framework of the International H 2 O Project (IHOP_2002). Weckwerth et al. (2004) provide a full discussion of the observational network, measurement strategy, and instruments

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