Search Results

You are looking at 111 - 120 of 9,049 items for :

  • Journal of the Atmospheric Sciences x
  • All content x
Clear All
Chidong Zhang and Peter J. Webster

I APRIL 1992 ZHANG AND WEBSTER 585Laterally Forced Equatorial Perturbations in a Linear Model. Part I: Stationary Transient Forcing CHIDONG ZHANG AND PETER J. WEBSTERDepartment of Meteorology, The Pennsylvania State University, University Park, Pennsylvania(Manuscript received 4 May 1990, in final form I April 1991)ABSTRACT Atmospheric equatorihl perturbations generated by

Full access
Ming-Dah Chou, Pui-King Chan, and Menghua Wang

–aerosol–transport model driven by model simulated/assimilated atmospheric temperature, humidity, and cloud fields. The products include not only the optical thickness but also the single scattering albedo and asymmetry factor, all of which are important for computing the radiative effect of aerosols [or aerosol radiative forcing (ARF)]. The National Aeronautics and Space Administration (NASA) launched the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) satellite on 1 August 1997 to measure global ocean color and to

Full access
J. Davoudi, N. A. McFarlane, and T. Birner

1. Introduction The concept of statistical quasi-equilibrium (QE) of moist convection was first introduced by Arakawa and Schubert (1974) , Arakawa (2004) , and Emanuel (1994) . The quasi-equilibrium hypothesis is based on the assumption that the time scale by which the kinetic energy of moist convection adjusts to changes in the large-scale forcing is small compared to that over which the forcing evolves. Convective quasi-equilibrium postulates that fast removal of buoyancy by moist

Full access
Marta Abalos, William J. Randel, and Encarna Serrano

1. Introduction Tropical upwelling is an important component of the Brewer–Dobson circulation (BDC), strongly influencing temperature and tracer distributions in the tropical lower stratosphere (e.g., Holton et al. 1995 ; Plumb 2002 ; Shepherd 2007 ). The tropical BDC is mainly driven by momentum deposition from large- and small-scale waves, but the relative roles of different forcing regions and their contributions for variability on different time scales are topics of ongoing research (e

Full access
Katherine H. Straub and George N. Kiladis

02 ), but have not addressed the mechanisms by which Kelvin waves might be initially excited. In this paper, we argue that a substantial fraction of convectively coupled Kelvin waves are excited through a distinct forcing from the extratropics. Extratropical forcing has also been suggested to play an important role in initiating lower-frequency MJO events ( Liebmann and Hartmann 1984 ; Hsu et al. 1990 ; Meehl et al. 1996 ; Lin et al. 2000 ; Straus and Lindzen 2000 ). Convectively coupled

Full access
Jin-Yi Yu and Dennis L. Hartmann

3244 JOURNAL OF THE ATMOSPHERIC SCIENCES VOL. 50, NO. 19Zonal Flow Vacillation and Eddy Forcing in a Simple GCM of the Atmosphere JIN-YI -U AND DENNIS L. HARTMANN Department of .4tmospheric Sciences, University of Washington. Seattle, Washington (Manuscript received 4 September 1992, in final form 8 December 1992) Zonal flow vacillation with very long time scales is

Full access
Long Li and Terrence R. Nathan

3412 JOURNAL OF THE ATMOSPHERIC SCIENCES VOL. 51, No. 23The Global Atmospheric Response to Low-Frequency Tropical Forcing: Zonally Averaged Basic States LONG LI AND TERRENCE R. NATHANAtmospheric Science Program, Department of Land, Air and Water Resources, University of California, Davis, California(Manuscript received 5 November 1993, in final form 16 March 1994)ABSTRACT The

Full access
R. Rõõm and A. Männik

at longer scales. For this reason we will test the AEM simultaneously with the EFM. And finally, an object for mutual testing is the HS primitive equation model (HSM), which represents the long-wave asymptote of the AEM. These three filtered models are compared with the ExM. Testing compares the linear response of different models to orographic forcing. First, all model equations are linearized; the wave equations for vertical displacements of material particles are derived. Then, exact

Full access
J. R. Holton, J. H. Beres, and X. Zhou

1. Introduction Thermal forcing by latent heating associated with convective storms is believed to be a major source of small-scale gravity waves. Thermal forcing by latent heating is typically at a maximum in the midtroposphere and varies in the vertical somewhat like a half-sine wave. Studies of the generation of large-scale equatorial wave modes by thermal forcing (e.g., Hayashi 1976 ; Salby and Garcia 1987 ) emphasize that the dominant wave response occurs for waves with vertical

Full access
Jie Song

). Feldstein (2003) found that the composite life cycle (growth and decay) of NAO events in reanalysis data is about 2 weeks. These results indicate that the fundamental physical processes of the NAO should lie in intraseasonal time scales. The NAO is largely an internal variability of the atmosphere ( Hurrell et al. 2003 ). Several studies found that the NAO is accompanied by significant anomalous transient eddy vorticity forcing (EVF), particularly in the upper troposphere (e.g., Jin et al. 2006

Full access