Search Results

You are looking at 1 - 9 of 9 items for :

  • Boundary currents x
  • Fifth International Symposium on Tropospheric Profiling (ISTP) x
  • All content x
Clear All
Steven E. Koch, Cyrille Flamant, James W. Wilson, Bruce M. Gentry, and Brian D. Jamison

the boundary layer act as strong focusing agents for triggering new convection or, at times, enhancing existing storms. For this reason, low-level convergence boundaries and associated fields of moisture were a focus in IHOP_2002. Of particular interest in the current study are the convergence zones associated with density currents, bores, and solitons ( Doviak and Ge 1984 ; Droegemeier and Wilhelmson 1985 ; Wilson and Schreiber 1986 ; Mueller and Carbone 1987 ; Karyampudi et al. 1995 ; Koch

Full access
Rod Frehlich, Yannick Meillier, and Michael L. Jensen

; Klipp and Mahrt 2004 ; Baas et al. 2006 ). In addition, the separation of the atmospheric variables into a turbulent component and a mean or slowly variable component can be ill posed, especially for statistics such as variances and fluxes for challenging conditions such as stable boundary layers ( Kaimal and Finnigan 1994 ; Mahrt 1998 ; Vickers and Mahrt 2003 ) and larger-scale forcing such as with a density current and a frontal passage ( Piper and Lundquist 2004 ). The standard analysis

Full access
P. C. S. Devara, P. E. Raj, K. K. Dani, G. Pandithurai, M. C. R. Kalapureddy, S. M. Sonbawne, Y. J. Rao, and S. K. Saha

forcing influences the aerosol patterns that are formed because of surface-generated aerosols, especially during the early morning transition from a stable to convective boundary layer and the late evening transition from a convective to a stable boundary layer ( Lenshow et al. 1979 ). Lidars play an important role in these studies because of their capability to make very precise continuous measurements of different aerosol and cloud parameters ( McCormick et al. 1993 ). Detailed knowledge of aerosols

Full access
Daniela Nowak, Dominique Ruffieux, Judith L. Agnew, and Laurent Vuilleumier

FMCW cloud radar. Provided the maximum signal in a profile was higher than a threshold value (indicating the presence of cloud), the height of the maximum radar reflectivity was registered. A second threshold value was specified for determining the cloud top. The height at which the reflectivity decreased below this second threshold value was taken as the cloud top. The current configuration allowed the detection of the upper boundary for one cloud layer only. Human eye observations (“synop”) were

Full access
Ulrich Löhnert, S. Crewell, O. Krasnov, E. O’Connor, and H. Russchenberg

1. Introduction Continuous profiling of the thermodynamic state of the atmosphere is becoming more and more important in support of mesoscale models, which are increasingly employed for numerical weather prediction (NWP). Especially the development of the boundary layer (BL), for example, its diurnal cycle or its influence on the initiation of convection, is crucial for the correct prediction of regional weather scales, including severe events, such as extreme precipitation. In this context the

Full access
Matthias Grzeschik, Hans-Stefan Bauer, Volker Wulfmeyer, Dirk Engelbart, Ulla Wandinger, Ina Mattis, Dietrich Althausen, Ronny Engelmann, Matthias Tesche, and Andrea Riede

forecasting. In this study, we are focusing on the determination of initial fields for mesoscale atmospheric modeling. Here, mathematical problems are indeed still an issue, as pointed out (e.g., in Rosatti et al. 2005 ; Steppeler et al. 2006 ). Furthermore, mesoscale forecasts are highly sensitive to the quality of model physics including land surface exchange ( Cheng and Cotton 2004 ; Trier et al. 2004 ; Holt et al. 2006 ), boundary layer properties ( Bright and Mullen 2002 ; Berg and Zhong 2005

Full access
B. L. Cheong, R. D. Palmer, T-Y. Yu, K-F. Yang, M. W. Hoffman, S. J. Frasier, and F. J. Lopez-Dekker

implemented using CRI with the exact same data, thus, eliminating concerns such as temporal separation and statistical stationarity. In this work, the turbulent eddy profiler (TEP), developed by the University of Massachusetts ( Mead et al. 1998 ), is used. TEP is a unique 915-MHz boundary layer imaging radar with an array of up to 64 independent receivers. Using adaptive array processing, three-dimensional volumetric images can be constructed within the field of view with a temporal resolution of

Full access
Edwin F. Campos, Wayne Hocking, and Frédéric Fabry

stratiform systems) present a much larger variation in the vertical than in the horizontal. Given this, we would expect that our assumption will be compromised only by particular observations, such as those at the boundaries of convective precipitation. Consequently, When applying the method in Fig. 1 , we also used the values in Table 1 for the VHF wind profiler. These values correspond to the McGill VHF radar, operating only in a vertical direction. Further description of this radar is

Full access
V. Bellantone, I. Carofalo, F. De Tomasi, M. R. Perrone, M. Santese, A. M. Tafuro, and A. Turnone

, allows fractional collection of particles on seven quartz filters with 50% effective-cut diameter ( d c ) of 5.7, 2.7, 1.4, 0.65, 0.35, 0.14, and 0.08 μ m, respectively. Morphological, elemental, and chemical analyses by scanning electron microscopy (SEM) and ion chromatography are performed to characterize the particles collected on filters. Ground meteorological parameters (e.g., temperature, relative humidity, wind direction, and wind speed) and the height of the planetary boundary layer (PBL

Full access