Search Results

You are looking at 81 - 90 of 2,076 items for :

  • Mesoscale forecasting x
  • Journal of the Atmospheric Sciences x
  • Refine by Access: Content accessible to me x
Clear All
Thomas Kilpatrick, Niklas Schneider, and Bo Qiu

. Section 3 describes the free-atmosphere response to the SST front, and section 4 describes the MABL response. Section 5 provides a summary and discussion, including a recommendation for an MABL model that is well suited for SST frontal zones. 2. Regional atmospheric model configuration The atmospheric response to an idealized midlatitude SST front is explored here with the nonhydrostatic Weather Research and Forecasting (WRF) Model, version 3.3.1 ( Skamarock et al. 2008 ). WRF has been used to

Full access
M. Oltmanns, F. Straneo, H. Seo, and G. W. K. Moore

1. Introduction Downslope winds in southeast Greenland can reach hurricane intensity, posing a threat to the local population ( Rasmussen 1989 ; Born and Böcher 2000 ; Klein and Heinemann 2002 ; Heinemann and Klein 2002 ; Mernild et al. 2008 ). They are especially pronounced within the valley of Ammassalik, where the flow is funneled by the topography ( Figs. 1 and 5 ). Using the European Centre for Medium-Range Weather Forecasts (ECMWF) interim reanalysis (ERA-I), Oltmanns et al. (2014

Full access
M. A. Kuester, M. J. Alexander, and E. A. Ray

sampling rates. In this paper, regional and local analysis tools are used to investigate wave sources, properties, and behavior in the lower stratosphere above a tropical cyclone environment. Simulations of Humberto are developed using the fifth-generation Pennsylvania State University –National Center for Atmospheric Research (PSU–NCAR) Mesoscale Model (MM5). Humberto was observed in September 2001 during the fourth field campaign in the National Aeronautics and Space Administration’s (NASA

Full access
Yefim L. Kogan and Alexei Belochitski

, employs many bins to discretize drop size distributions (DSDs), which evolve unconstrained according to microphysical processes of condensation/evaporation, coalescence, gravitational sedimentation, etc. The explicit microphysics approach is computationally expensive, but it is also limited to high-resolution models, as the coarse spatial grid of mesoscale and large-scale models does not allow prediction of the local supersaturation needed for calculation of drop condensational growth. The

Full access
Alexander D. Schenkman, Ming Xue, and Alan Shapiro

upright, leading to more intense stretching of low-level vorticity. This result has recently been confirmed in a study by Schenkman et al. (2011a , hereafter S11a) , wherein real-data experiments that more effectively analyzed low-level shear forecasted stronger, longer-lived mesovortices. The dynamical link between mesovortices and tornadoes remains relatively unexplored. To the authors’ knowledge, no study has examined a case with sufficient resolution (either observationally or numerically) to

Full access
M. Virman, M. Bister, V. A. Sinclair, J. Räisänen, and H. Järvinen

1. Introduction The majority of precipitation over tropical oceans is associated with mesoscale convective systems (MCSs; Rickenbach and Rutledge 1998 ), which produce both stratiform and convective precipitation (e.g., Houze 2018 ). The vertical heating profile associated with MCSs over the moistest regions of tropical oceans has been shown to be positive at all altitudes with its maximum in the upper troposphere (e.g., Houze 1982 ). The heating associated with MCSs strongly influences the

Free access
Jannik Wilhelm, T. R. Akylas, Gergely Bölöni, Junhong Wei, Bruno Ribstein, Rupert Klein, and Ulrich Achatz

atmospheric applications is the second (hydrostatic) limit, for which the mesoscale-wave impact is the strongest. For instance, taking ( H m , L m ) = (1, 100) km and f / N * = 10 −2 , from (20) it is then found that ( H w , L w ) = (0.1, 1) km. Notably, this scale estimate is in good agreement with present-day local-area weather-forecast-code mesh distances (see section 1 ). For later reference, Table 1 provides an overview of the scales deduced in this section. It is worth noting that the

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

). The reason for larger flash density in outer bands remains somewhat uncertain”. Note in this connection that simulations of evolution of an idealized hurricane by FL07 —using a mesoscale 2-km-resolution model with a bulk parameterization scheme describing 12 distinct hydrometeor habits ( Straka and Mansell 2005 ) and a lightning scheme ( Mansell et al. 2002 )—showed much more intense convection and lightning within a TC in the ∼50-km-radius central convective zone than in the outer rainbands

Full access
Thomas R. Parish and Larry D. Oolman

Forecasting Nonhydrostatic Mesoscale Model (NAM) for July 2008 are used here to depict the basic structure of the LLJ. Three-hourly output grids are used for each day based on the 0000 UTC forecasts, commencing at 0300 UTC and continuing until 0000 UTC the following day. Inspection of the mean values for July 2008 shows that the NAM is able to simulate the LLJ. As an example, Fig. 1a shows the mean July 2008 LLJ vertical profile at selected times of the day for the grid point corresponding to Enid

Full access
Yuan Wang, Lifeng Zhang, Jun Peng, and Jiping Guan

imply that gravity waves in the mei-yu front system are substantially different from traditional (classical) frontal gravity waves? How will the prominent role of the moisture and diabatic heating in the mei-yu front system affect gravity waves? Both topics are worth exploring and studying. Recently, Peng et al. (2014a , b) constructed an idealized mei-yu front model based on the Weather Research and Forecasting (WRF) Model and used it to study the mesoscale energy spectral characteristics of the

Full access