Search Results

You are looking at 61 - 70 of 7,107 items for :

  • Diabatic heating x
  • All content x
Clear All
Isidoro Orlanski and Silvina Solman

the large-scale atmospheric circulation. For both heavy and light ice cases, the atmospheric response occurs not only in the region of the sea ice but far downstream in the form of a stationary wave train propagating along a great circle, extending the sea ice response from the polar regions to well into the middle latitudes. In this paper we suggest a different mechanism for the enhancement of external waves. We demonstrate that external waves could be destabilized by diabatic heating and, in

Full access
Cameron R. Homeyer, Courtney Schumacher, and Larry J. Hopper Jr.

1. Introduction Atmospheric motions can occur, in part, because of the nonuniformity of diabatic heating processes associated with precipitating cloud systems. This concept is especially relevant in the tropics where variations in the vertical structure of heating play an important role in the large-scale circulation through the generation of potential vorticity anomalies. Houze (1982) observed that the maximum heating (composed of latent, radiative, and eddy sensible components) in

Full access
Xianan Jiang, Duane E. Waliser, William S. Olson, Wei-Kuo Tao, Tristan S. L’Ecuyer, Jui-Lin Li, Baijun Tian, Yuk L. Yung, Adrian M. Tompkins, Stephen E. Lang, and Mircea Grecu

). It is noted that positive heating prevails during most of the 6-month period in the EC models regardless of the MJO phases. In contrast, diabatic cooling is evident in a large portion of troposphere during the undisturbed phases of the MJO, and it is also dominant in the PBL in both of TRMM estimates. This PBL cooling is associated with both radiation and stratiform cloud processes below the melting level as to be shown later. Additionally, the maximum heating centers tend to appear in the middle

Full access
Patrick Ludwig, Joaquim G. Pinto, Simona A. Hoepp, Andreas H. Fink, and Suzanne L. Gray

, the shear at the frontal zone, the weakening of large-scale strain (or stretching deformation) field in the environment of the front, diabatic heating effects due to latent heat release inside clouds, boundary layer processes, and the influence of a local strip of maximum potential vorticity (PV) are mentioned as decisive mechanisms for secondary cyclogenesis. Several studies investigated the influence of the environmental deformation field on frontal wave development. An idealized study by

Full access
Thomas J. Galarneau Jr., Lance F. Bosart, Christopher A. Davis, and Ron McTaggart-Cowan

discussion of MCVs MCVs are warm-core systems (in the middle and lower troposphere) that have been documented to form in the trailing stratiform region of MCSs (e.g., Johnston 1982 ; Zhang and Fritsch 1987 ; Menard and Fritsch 1989 ; Bartels et al. 1997 ; Johnson and Mapes 2001 ). Cyclonic and anticyclonic relative vorticity maxima are characteristically found in middle and upper levels, respectively, in association with a diabatic heating maximum. An anticyclonic, or weakly cyclonic, relative

Full access
Yuki Hayashi and Kaoru Sato

f plane is used (i.e., β effects are neglected), as a Rossby wave–type response is not expected in zonal-mean equations. Linear relaxation terms with the same relaxation factor κ are included in the momentum equations [ (3) and (4) ] and thermodynamic equation [ (6) ]. Three external forcings (zonal forcing X , meridional forcing Y , and diabatic heating ) are given. These equations are translated into their dimensionless forms. Assuming that the horizontal and vertical spatial scales

Open access
Christopher G. Marciano, Gary M. Lackmann, and Walter A. Robinson

-dynamic literature, and has been quantified using potential vorticity (PV) inversion (e.g., Davis and Emanuel 1991 ; Davis 1992 ; Davis et al. 1993 ; Balasubramanian and Yau 1994 ; Stoelinga 1996 ; Huo et al. 1999 ). Latent heat release is crucial to type-C cyclogenesis in which the intensification of the surface cyclone is driven by latent heat release and the formation of an intense low-level diabatic PV anomaly ( Plant et al. 2003 ; Ahmadi-Givi et al. 2004 ). Latent heating has also been shown to be

Full access
Chun-Chieh Wu, Shun-Nan Wu, Ho-Hsuan Wei, and Sergio F. Abarca

important role in the TC structure evolution. Studies based on highly idealized integrations point to the importance of diabatic heating in maintaining a ringlike structure in the TC. Rozoff et al. (2009) used a prescribed annular vorticity source (aimed to mimic the azimuthal-mean component of asymmetric convection in a real TC) in a forced-barotropic nondivergent model to assess the influence of the heating source on the ring structure evolution. The results showed that the presence of a heating

Full access
Zhenhai Zhang and F. Martin Ralph

–500 hPa, which is over 70% stronger than the NO-AR-G cases (~7 K day −1 ) as shown in Figs. 9a and 9b . The stronger latent heating can enhance the vertical motion and the generation of kinetic energy, which was investigated by many previous studies ( Danard 1964 ; Chang et al. 1984 ). The latent heat release can also generate cyclonic diabatic potential vorticity (PV) in the lower troposphere, which is an important factor to enhance ETC intensification in the genesis stage ( Davis and Emanuel 1991

Open access
Kristine F. Haualand and Thomas Spengler

studied in conjunction with latent heating. Investigating both of these diabatic effects in baroclinic life cycle experiments using a primitive equation global spectral model, Gutowski and Jiang (1998) found that surface heat fluxes destabilize the cold sector and stabilize the warm sector, resulting in a shift of convective heating to the cold sector. Consequently, in a follow-up study including constant surface sensible heat fluxes, Jiang and Gutowski (2000) examined the effect of convective

Open access