scholarly journals Stratospheric Circulation of the Northern Hemisphere Winter during 1989-90.

1992 ◽  
Vol 44 (11) ◽  
pp. 1097-1106 ◽  
Author(s):  
Toshihiko HIROOKA ◽  
Kazuhiko HAYASHI ◽  
Shinichi YAMADA
Keyword(s):  
Northern Hemisphere ◽  
Stratospheric Circulation ◽  
Hemisphere Winter ◽  
Northern Hemisphere Winter

scholarly journals Stationary planetary wave propagation in Northern Hemisphere winter – climatological analysis of the refractive index

2007 ◽  
Vol 7 (1) ◽  
pp. 183-200 ◽  
Author(s):  
Q. Li ◽  
H.-F. Graf ◽  
M. A. Giorgetta
Keyword(s):  
Refractive Index ◽  
Wave Propagation ◽  
Northern Hemisphere ◽  
Planetary Wave ◽  
Planetary Waves ◽  
Mean Flow ◽  
Stratospheric Circulation ◽  
Hemisphere Winter ◽  
Planetary Wave Propagation ◽  
Northern Hemisphere Winter

Abstract. The probability density on a height-meridional plane of negative refractive index squared f(nk2<0) is introduced as a new analysis tool to investigate the climatology of the propagation conditions of stationary planetary waves based on NCEP/NCAR reanalysis data for 44 Northern Hemisphere boreal winters (1958–2002). This analysis addresses the control of the atmospheric state on planetary wave propagation. It is found that not only the variability of atmospheric stability with altitudes, but also the variability with latitudes has significant influence on planetary wave propagation. Eliassen-Palm flux and divergence are also analyzed to investigate the eddy activities and forcing on zonal mean flow. Only the ultra-long planetary waves with zonal wave number 1, 2 and 3 are investigated. In Northern Hemisphere winter the atmosphere shows a large possibility for stationary planetary waves to propagate from the troposphere to the stratosphere. On the other hand, waves induce eddy momentum flux in the subtropical troposphere and eddy heat flux in the subpolar stratosphere. Waves also exert eddy momentum forcing on the mean flow in the troposphere and stratosphere at middle and high latitudes. A similar analysis is also performed for stratospheric strong and weak polar vortex regimes, respectively. Anomalies of stratospheric circulation affect planetary wave propagation and waves also play an important role in constructing and maintaining of interannual variations of stratospheric circulation.

scholarly journals Stationary planetary wave propagation in Northern Hemisphere winter – climatological analysis of the refractive index

2006 ◽  
Vol 6 (5) ◽  
pp. 9033-9067 ◽  
Author(s):  
Q. Li ◽  
H.-F. Graf ◽  
M. A. Giorgetta
Keyword(s):  
Refractive Index ◽  
Wave Propagation ◽  
Northern Hemisphere ◽  
Planetary Wave ◽  
Planetary Waves ◽  
Mean Flow ◽  
Stratospheric Circulation ◽  
Hemisphere Winter ◽  
Planetary Wave Propagation ◽  
Northern Hemisphere Winter

Abstract. The probability density on a height-meridional plane of negative refractive index squared f(nk2<0) is introduced as a new analysis tool to investigate the climatology of the propagation properties of stationary planetary waves based on NCEP/NCAR reanalysis data for 44 Northern Hemisphere boreal winters (1958–2002). This analysis shows the control of the atmospheric state on planetary wave propagation. It is found that not only the variability of atmospheric stability with altitudes, but also the variability with latitudes has significant influence on planetary wave propagation. Eliassen-Palm flux and divergence are also analyzed to investigate the eddy activities and forcing on zonal mean flow. Only the ultra-long planetary waves with zonal wave number 1, 2 and 3 are investigated. In Northern Hemisphere winter the atmosphere shows a large possibility for stationary planetary waves to propagate from the troposphere to the stratosphere. On the other hand, waves induce eddy momentum flux in the subtropical troposphere and eddy heat flux in the subpolar stratosphere. Waves also exert eddy momentum forcing on the mean flow in the troposphere and stratosphere at middle and high latitudes. A similar analysis is also performed for stratospheric strong and weak polar vortex regimes, respectively. Anomalies of stratospheric circulation affect planetary wave propagation and waves also play an important role in constructing and maintaining of interannual variations of stratospheric circulation.

scholarly journals Predictability Changes of Stratospheric Circulations in Northern Hemisphere Winter

2016 ◽  
Vol 94 (1) ◽  
pp. 7-24 ◽  
Author(s):  
Tomoko ICHIMARU ◽  
Shunsuke NOGUCHI ◽  
Toshihiko HIROOKA ◽  
Hitoshi MUKOUGAWA
Keyword(s):  
Northern Hemisphere ◽  
Hemisphere Winter ◽  
Northern Hemisphere Winter

scholarly journals Polar stratospheric cloud observations by MIPAS on ENVISAT: detection method, validation and analysis of the northern hemisphere winter 2002/2003

2005 ◽  
Vol 5 (3) ◽  
pp. 679-692 ◽  
Author(s):  
R. Spang ◽  
J. J. Remedios ◽  
L. J. Kramer ◽  
L. R. Poole ◽  
M. D. Fromm ◽  
...  
Keyword(s):  
Northern Hemisphere ◽  
Detection Method ◽  
Michelson Interferometer ◽  
The Arctic ◽  
Spectral Signature ◽  
Winter Period ◽  
Second Phase ◽  
Good Correspondence ◽  
Hemisphere Winter ◽  
Northern Hemisphere Winter

Abstract. The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) on ENVISAT has made extensive measurements of polar stratospheric clouds (PSCs) in the northern hemisphere winter 2002/2003. A PSC detection method based on a ratio of radiances (the cloud index) has been implemented for MIPAS and is validated in this study with respect to ground-based lidar and space borne occultation measurements. A very good correspondence in PSC sighting and cloud altitude between MIPAS detections and those of other instruments is found for cloud index values of less than four. Comparisons with data from the Stratospheric Aerosol and Gas Experiment (SAGE) III are used to further show that the sensitivity of the MIPAS detection method for this threshold value of cloud index is approximately equivalent to an extinction limit of 10-3km-1 at 1022nm, a wavelength used by solar occultation experiments. The MIPAS cloud index data are subsequently used to examine, for the first time with any technique, the evolution of PSCs throughout the Arctic polar vortex up to a latitude close to 90° north on a near-daily basis. We find that the winter of 2002/2003 is characterised by three phases of very different PSC activity. First, an unusual, extremely cold phase in the first three weeks of December resulted in high PSC occurrence rates. This was followed by a second phase of only moderate PSC activity from 5-13 January, separated from the first phase by a minor warming event. Finally there was a third phase from February to the end of March where only sporadic and mostly weak PSC events took place. The composition of PSCs during the winter period has also been examined, exploiting in particular an infra-red spectral signature which is probably characteristic of NAT. The MIPAS observations show the presence of these particles on a number of occasions in December but very rarely in January. The PSC type differentiation from MIPAS indicates that future comparisons of PSC observations with microphysical and denitrification models might be revealing about aspects of solid particle existence and location.

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