Search Results

You are looking at 181 - 190 of 5,095 items for :

  • Planetary waves x
  • Journal of the Atmospheric Sciences x
  • Refine by Access: All Content x
Clear All
Naftali Y. Cohen and Edwin P. Gerber, and Oliver Bühler

Lagrangian-mean velocities for zonal-mean steady disturbances (e.g., Bühler 2009 , chapter 11). Moreover, in the quasigeostrophic (QG) approximation the TEM equations provide a clear causality of the wave–mean flow driving, a point that is emphasized in the “downward control” principle ( Haynes et al. 1991 ). Planetary-scale Rossby waves and small-scale gravity waves are the primary drivers of the circulation in the middle atmosphere, where planetary waves dominate in the stratosphere and gravity waves

Full access
Hamid A. Pahlavan, John M. Wallace, Qiang Fu, and George N. Kiladis

middle stratosphere, with a good representation of planetary waves (e.g., Ern and Preusse 2009a , b ; Kim et al. 2019 ). However, in Pahlavan et al. (2021 , hereafter Part I ), we showed that the forcing due to the resolved SSG waves in ERA-I to be negligible, in particular in the easterly shear zones, consistent with the results of Ern et al. (2014) . Here we revisit the QBO using ERA5, the fifth generation of ECMWF atmospheric reanalyses ( Hersbach et al. 2020 ). The higher spatial resolution

Restricted access
Richard S. Lindzen

1452 JOURNAL OF THE ATMOSPHERIC SCIENCES Vo~.ma~29Equatorial Planetary Waves in Shear: Part H RICHARD S. LnqDZENzDept. of th. Geophysical Sciences, Ths University of Chicago 60637(Manuscript received 12 May 1972, in revised form 10 July 1972)ABSTRACT The general problem of the vertical propagation of equatorial waves through mean fields with verticalshear is solved analytically for all meridional

Full access
Gui-Ying Yang and Brian J. Hoskins

–time diagrams, phase speed is often simply estimated from a slope line on the plot. However, here a more objective way, the Radon transform method, is used. This method can objectively compute the direction of travel of the wave in the longitude–time domain and, thus, its phase speed. The method was first described by Radon (1917) and has been applied in studies of oceanic planetary waves (e.g., Challenor et al. 2001 ) and atmospheric waves ( Yang et al. 2007b ). A brief introduction to this method and an

Full access
Richard S. Lindzen

formulas for the various wave fields are obtained, and the role ofdissipation and the behavior of momentum and energy fluxes are investigated. Results are compared withboth numerical calculations and with observations. From the latter, we are able to estimate the dissipativetime scale in the tropical stratosphere. On the basis of the above findings, the Lindzen-Holton model of the quasi-biennial oscillation is modified.1. Introduction For several years now, long-period (5-12 days),planetary

Full access
Michael J. Kavulich Jr., Istvan Szunyogh, Gyorgyi Gyarmati, and R. John Wilson

s = 60° takes 66.7 Sols, making the Northern Hemisphere winter significantly shorter than the Northern Hemisphere summer. In this paper, we refer to the time of the year by L s but describe the period and the frequency of the waves in Sols. c. The GFDL MGCM The GFDL MGCM has been used in a large number of studies of the Martian atmosphere. These studies have included investigations of tides and planetary waves ( Wilson and Hamilton 1996 ; Hinson and Wilson 2002 ; Wilson 2000 ; Hinson et al

Full access
Malcolm J. King, Matthew C. Wheeler, and Todd P. Lane

affect how these planetary waves propagate near the surface and lead to convergence and divergence that is sufficiently strong to modulate convection, despite the large-scale convergence being small. However, it is worth keeping in mind that the level of total precipitation variance attributable to the 5-day wave is rather low— Fig. 2 shows that over the whole year, the level of 6-hourly precipitation variance directly attributable to the 5-day wave is at most 2 mm 2 day −2 and comprises only over

Full access
Min-Jee Kang, Hye-Yeong Chun, and Byeong-Gwon Song

altitude, which is not the case for WACCM4. In addition, the CGW parameterization in Chun et al. (2011) ( Choi and Chun 2011 ) induces strong westward CGWD in the lower stratosphere at 30°–50°N/S, where strong source-level CGWs exist in association with winter-hemispheric storm-track regions, which is different from the CGW parameterization in WACCM4 ( Beres et al. 2005 ). Recently, Cohen et al. (2014) showed that an increase in GW forcing decreases planetary wave forcing and vice versa, which was

Free access
Pi-Huan Wang, M. P. McCormick, and W. P. Chu

OCTOBER 1983 PI-HUAN WANG, M. P. MCCORMICK AND W. P. CHU2419A Study on the Planetary Wave Transport of Ozone during the Late February 1979Stratospheric Warming Using the SAGE Ozone Observationand Meteorological InformationPI-HUAN WANGInstitute for Atmospheric Optics and Remote Sensing (IFAORS), Hampton, VA 23666 M. P. MCCORMICK AND W. P. CHUNASA Langley Research Center, Hampton, VA 23665(Manuscript received 30 August 1982, in final form 8 June 1983)ABSTRACT Ozone data from

Full access
Charles McLandress, John F. Scinocca, Theodore G. Shepherd, M. Catherine Reader, and Gloria L. Manney

dynamical features of warming events like those in 2006 and 2009—in particular, the elevated stratopause and its subsequent descent. Using the Whole Atmosphere Community Climate Model (WACCM), Limpasuvan et al. (2012) argued that the formation of the elevated stratopause and its initial descent were due to mesospheric planetary wave drag. Hitchcock and Shepherd (2013) used a time-dependent zonally averaged quasigeostrophic model driven by the zonal-mean torques from a free-running version of CMAM to

Full access