Search Results

You are looking at 31 - 40 of 5,109 items for :

  • Planetary waves x
  • Journal of the Atmospheric Sciences x
  • Refine by Access: All Content x
Clear All
Anne K. Smith

1. Introduction Quasi-stationary planetary-scale waves are a dominant feature of the winter middle atmosphere. The magnitude and variability of these waves in the stratosphere have been characterized from decades of radiosonde and more recently satellite observations. A body of theory, beginning with the classic study of Charney and Drazin (1966) , has been able to explain most features of the observed waves in the stratosphere. A smaller body of satellite observations for the upper mesosphere

Full access
Roland A. Madden

SEPTEMBER 1978 R O L A N D' A. M A D D E N 1605Further Evidence of Traveling Planetary Waves ROLAND A. MADDENNational Center for Atmospheric Research,~ Boulder, CO 80307(Manuscript received 1 March 1978, in final form 1 May 1978)ABSTRACT Evidence of regularly propagating, laige-scale waves is found in a 73-year record of Northern Hemispheresea-level pressure data and in a nine-year record.of upper

Full access
Kevin E. Trenberth and Shyh-Chin Chen

2934 JOURNAL OF THE ATMOSPHERIC SCIENCES VOL. 45, NO. 20Planetary Waves Kinematica!ly Forced by Himalayan Orography KEVlN E. TRENBERTHNational Center for Atmosoheric Research.* Boulder, Colorado SHYH..CHIN CI-~ENScripps Institution of Oceanography, La Jolla, California(Manuscript received 4 December 1987, in final form 13 April 1988) An analysis is made of the planetary-seale response

Full access
Diane Pendlebury and Theodore G. Shepherd

circulation ( Dunkerton 1989 ; Plumb and Eluszkiewicz 1999 ; Semeniuk and Shepherd 2001b ). The applied torque that drives the Brewer–Dobson circulation arises mainly from planetary-scale Rossby waves, which are generated in the troposphere and propagate into the middle atmosphere where they grow in amplitude, break, and dissipate. (The stratospheric circulation is also affected by gravity wave drag, but this is a secondary contribution.) Dissipating planetary waves apply a negative torque, and so

Full access
Carlos F. M. Raupp and Pedro L. Silva Dias

1. Introduction The atmospheric flow is characterized by the existence of low-frequency fluctuations with time scales ranging from 20 to around 100 days ( Madden and Julian 1972 , 1994 ; Hayashi and Golder 1993 ; Ghil and Mo 1991 ). The dominant component of this intraseasonal variability of the atmospheric circulation in the tropics is the 40–50-day Madden–Julian oscillation (MJO), which is characterized in the troposphere by a planetary-scale (wavenumber 1–2) wave envelope having an

Full access
Ping Chen and Walter A. Robinson

15DECEMBER 1992 CHEN AND ROBINSON 2533Propagation of Planetary Waves between the Troposphere and Stratosphere PING CHEN* AND WALTER A. ROBINSONDepartment of Atmospheric Sciences, University of lllinois at Urbana-Champaign, Urbana, Illinois(Manuscript received 30 September 1991, in final form 24 February 1992)ABSTRACT The propagation of planetary waves between the troposphere and

Full access
Thomas Birner and Paul D. Williams

1. Introduction The stratospheric circulation in winter is dominated by a strong cyclonic vortex over the pole. In principle, this polar vortex is driven by radiative cooling due to polar night. However, planetary waves frequently perturb the vortex in terms of both position and strength. For sufficiently strong planetary wave forcing, these disturbances can grow enough to destroy the polar vortex as a well-organized entity. These abrupt transitions are usually associated with a reversal of the

Full access
Jinggao Hu, Rongcai Ren, and Haiming Xu

1. Introduction The large-scale circulation in the extratropical stratosphere cycles between circumpolar westerlies during winter and circumpolar easterlies during summer every year. The winter circumpolar westerlies characterize the life cycle of the stratospheric polar vortex. In winter, planetary waves from the troposphere can penetrate into the stratosphere and perturb the circumpolar westerlies, which are responsible for the recurrent stratospheric sudden warming events (SSWs) ( Matsuno

Full access
Ming Cai and Mankin Mak

15DECEMBER 1990 MING CAI AND MANKIN MAK 2953Symbiotic Relation between Planetary and Synoptic-Scale Waves MING CAI* AND MANKIN MAKDepartment of Atmospheric Sciences, University of lllinois, Urbana, lllinois(Manuscript received 12 February 1990, in final form 13 June 1990) ABSTRACT It is hypothesized that the low-frequency planetary scale waves and the high

Full access
Xun Zhu, Jeng-Hwa Yee, E. R. Talaat, M. Mlynczak, and J. M. Russell III

1. Introduction In the mesosphere and lower thermosphere (MLT), tidal waves and planetary-scale waves are the leading modes of variability and have important global effects on circulation and photochemistry (e.g., Forbes et al. 1993 , 1997 ; Zhu et al. 2000 ). This makes the systematic and comprehensive studies of global change in the MLT from satellite measurements especially valuable. One of the fundamental problems in large-scale atmospheric dynamics is how the background zonal mean and

Full access