Search Results

You are looking at 1 - 10 of 22 items for :

  • Boundary conditions x
  • Review Articles in Monthly Weather Review x
  • All content x
Clear All
William H. Raymond and Arthur Garder

selectivity in the presence of topography. To make the implicit filters competitivewith the traditional recursive formalism, efficient numerical matrix inversion procedures are employed in theapplication of both limited area and cyclic boundary conditions.1. Introduction Filters are used to extract information from a signal.The discrimination process used by filters separates thedesired from the undesired using a built-in frequencydependence. The simplest type of filter is the nonrecursive. The other

Full access
Scott R. Fulton, Paul E. Ciesielski, and Wayne H. Schubert

nonlinear problems and boundary conditions. Multigrid applications, current research, andavailable software are also discussed. CONTENTS1. Introduction2. Classical methods a. Gaussian elimination b. Point iterative methods c. ADI method d. Discussion3. Basic multigrid concepts a. Analysis of relaxation b. A two-grid method c. A multigrid method4. Survey ofmultigrid techniques a. Relaxation schemes b. Grids c. Grid transfers d. Control algorithms 1) Cycling algorithms 2) Full

Full access
Robert Wood

of marine boundary layer cloud droplet number concentration from satellite . J. Geophys. Res. , 112 , D02201 , doi:10.1029/2006JD007547 . Bergman , J. W. , and M. L. Salby , 1996 : Diurnal variations of cloud cover and their relationship to climatological conditions . J. Climate , 9 , 2802 – 2820 . Berner , A. , C. S. Bretherton , and R. Wood , 2011 : Large-eddy simulation of mesoscale dynamics and entrainment around a pocket of open cells observed in VOCALS RF06 . Atmos

Full access
P. L. Houtekamer and Fuqing Zhang

applications in the future, but a lot of work has been accomplished since. At the Canadian Meteorological Centre (CMC), a global EnKF has been used operationally since January 2005 to provide the initial conditions for a global ensemble prediction system ( Houtekamer et al. 2005 ). In this system, observation preprocessing is done by a higher-resolution variational analysis system. At the time of this writing, the global EnKF is also used to provide initial and lateral boundary conditions to a regional

Full access
Tammy M. Weckwerth and David B. Parsons

convection. Wilson and Megenhardt (1997) undertook an extensive examination of these concepts from ∼30 days of radar data during the Convection and Precipitiation/Electrification (CaPE; e.g., Wakimoto and Lew 1993 ) experiment in Florida. The environment they investigated had low values of the vertical wind, and they found it useful to interpret their results in terms of the relative movement of storms and boundaries. Figure 3 shows favorable and unfavorable conditions for convection initiation and

Full access
Robert A. Houze Jr.

-layer stratus/stratocumulus at the top of the boundary layer. Pendergrass and Willoughby (2009) and Willoughby (2009) have shown that variations in hypothesized heating patterns associated with the eyewall and different environmental conditions lead to a variety of variations. The latter paper indicates that transient bursts of heating in the eyewall, for example from embedded buoyant convective towers, might produce significant alterations in the storm structure. The subsidence computed for the eye

Full access
Zhiyong Meng and Fuqing Zhang

applications of the EnKF in global and limited-area models. First, the LAM EnKF needs a proper way to perturb lateral boundary conditions. Second, as a result of the smaller scale of the systems of interest, model error might be more severe since the dynamics and physics of meso- to convective-scale systems are less well understood and thus likely to be more poorly represented in the model. Furthermore, there are more inhomogeneities in the spatial and temporal coverage of observations and more data

Full access
J. R. Garratt

of the windand temperature profiles, both for the _surface layer(Monin-Oboukhov similarity theory) and the remainderof the boundary layer (deficit formulation, e.g., Clarke,1970). Limited applications of Deardorff's parameterization scheme in a general circulation model have utilized values of z0, for land (from Fiedler and Panofsky,1970; see Deardorff, 1972) of 0.2-0.7 m (see Section 4)916 MONTHLy WEATHER REVIEW

Full access
Markus Gross, Hui Wan, Philip J. Rasch, Peter M. Caldwell, David L. Williamson, Daniel Klocke, Christiane Jablonowski, Diana R. Thatcher, Nigel Wood, Mike Cullen, Bob Beare, Martin Willett, Florian Lemarié, Eric Blayo, Sylvie Malardel, Piet Termonia, Almut Gassmann, Peter H. Lauritzen, Hans Johansen, Colin M. Zarzycki, Koichi Sakaguchi, and Ruby Leung

after being initialized from the operational Met Office global model analysis valid at 0000 UTC 18 August 2011. The lateral boundary conditions were provided every time step by a global model that was reinitialized from Met Office operational analyses every 6 h. The data presented here were taken from 0000 UTC 30 August 2011 after the convection-permitting simulation was fully spun up. The grid points are classified as cloudy or dry, depending on the presence or not of cloud condensate: the cloudy

Open access
Daniel Keyser and M. A. Shapiro

known, so that ~ (the response) can bedetermined uniquely provided that boundary conditions are specified and an ellipticity condition, Om O0 (Om'~2 '~ Oy 0.D ~-~--~] = ~P2 ~ 0, (3.13)is satisfied everywhere in the (y, p) domain. The equality within (3.13) can be verified by referring to (2.9)and (2.10) along with (2.6). The condition of positivepotential vorticity ensures that transverse ageostrophiccirculations will arise only in response to the

Full access