Dynamics of the atmosphere and seismic activity in the Baikal rift zone

We study the troposphere dynamics, temperature regime in the stratosphere, upper atmosphere emission, and seismic activity in the Baikal Rift Zone for winters 2011/2012 and 2012/2013. Variations of the lithospheric, tropospheric, stratospheric and mesosphe- ric characteristics occurred either simultaneously or with a time lag during these periods. We found that the wind speed in the lower atmosphere reached a maximum several days before the seismic activity increase in the region. Then, it de-creased to a minimum at the earthquake instant. The periods of this seismic activity growth coincided with episodes of stratospheric warm-ings and with an increase in the 557.7 nm atmospheric emission in the meso-sphere and the low thermosphere (85–115 km). A pos-sible reason for the correlations may be the increased atmospheric effects on mountains, the formation of vertical flows above mountains, and generation of planetary and gravity waves.

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Propagation of gravity waves and its effects on pseudomomentum flux in a sudden stratospheric warming event

Atmospheric Chemistry and Physics ◽

10.5194/acp-20-7617-2020 ◽

2020 ◽

Vol 20 (12) ◽

pp. 7617-7644

Author(s):

In-Sun Song ◽

Changsup Lee ◽

Hye-Yeong Chun ◽

Jeong-Han Kim ◽

Geonhwa Jee ◽

...

Keyword(s):

Ray Tracing ◽

Gravity Waves ◽

Lower Thermosphere ◽

Upper Atmosphere ◽

Lower Atmosphere ◽

Wave Number ◽

Horizontal Wind ◽

Stratospheric Warming ◽

Sudden Stratospheric Warming ◽

Curvature Effects

Abstract. Effects of realistic propagation of gravity waves (GWs) on distribution of GW pseudomomentum fluxes are explored using a global ray-tracing model for the 2009 sudden stratospheric warming (SSW) event. Four-dimensional (4D; x–z and t) and two-dimensional (2D; z and t) results are compared for various parameterized pseudomomentum fluxes. In ray-tracing equations, refraction due to horizontal wind shear and curvature effects are found important and comparable to one another in magnitude. In the 4D, westward pseudomomentum fluxes are enhanced in the upper troposphere and northern stratosphere due to refraction and curvature effects around fluctuating jet flows. In the northern polar upper mesosphere and lower thermosphere, eastward pseudomomentum fluxes are increased in the 4D. GWs are found to propagate more to the upper atmosphere in the 4D, since horizontal propagation and change in wave numbers due to refraction and curvature effects can make it more possible that GWs elude critical level filtering and saturation in the lower atmosphere. GW focusing effects occur around jet cores, and ray-tube effects appear where the polar stratospheric jets vary substantially in space and time. Enhancement of the structure of zonal wave number 2 in pseudomomentum fluxes in the middle stratosphere begins from the early stage of the SSW evolution. An increase in pseudomomentum fluxes in the upper atmosphere is present even after the onset in the 4D. Significantly enhanced pseudomomentum fluxes, when the polar vortex is disturbed, are related to GWs with small intrinsic group velocity (wave capture), and they would change nonlocally nearby large-scale vortex structures without substantially changing local mean flows.

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Propagation of gravity waves and its effects on pseudomomentum flux in a sudden stratospheric warming event

10.5194/egusphere-egu21-1909 ◽

2021 ◽

Author(s):

In-Sun Song ◽

Changsup Lee ◽

Hye-Yeong Chun ◽

Jeong-Han Kim ◽

Geonhwa Jee ◽

...

Keyword(s):

Ray Tracing ◽

Gravity Waves ◽

Lower Thermosphere ◽

Upper Atmosphere ◽

Lower Atmosphere ◽

Horizontal Wind ◽

Stratospheric Warming ◽

Sudden Stratospheric Warming ◽

Curvature Effects ◽

Zonal Wavenumber

Effects of realistic propagation of gravity waves (GWs) on distribution of GW pseudomomentum fluxes are explored using a global ray-tracing model for the 2009 sudden stratospheric warming (SSW) event. Four-dimensional (4D;&#160;x&#8211;z&#160;and&#160;t) and two-dimensional (2D;&#160;z&#160;and&#160;t) results are compared for various parameterized pseudomomentum fluxes. In ray-tracing equations, refraction due to horizontal wind shear and curvature effects are found important and comparable to one another in magnitude. In the 4D, westward pseudomomentum fluxes are enhanced in the upper troposphere and northern stratosphere due to refraction and curvature effects around fluctuating jet flows. In the northern polar upper mesosphere and lower thermosphere, eastward pseudomomentum fluxes are increased in the 4D. GWs are found to propagate more to the upper atmosphere in the 4D, since horizontal propagation and change in wave numbers due to refraction and curvature effects can make it more possible that GWs elude critical level filtering and saturation in the lower atmosphere. GW focusing effects occur around jet cores, and ray-tube effects appear where the polar stratospheric jets vary substantially in space and time. Enhancement of the structure of zonal wavenumber 2 in pseudomomentum fluxes in the middle stratosphere begins from the early stage of the SSW evolution. An increase in pseudomomentum fluxes in the upper atmosphere is present even after the onset in the 4D. Significantly enhanced pseudomomentum fluxes, when the polar vortex is disturbed, are related to GWs with small intrinsic group velocity (wave capture), and they would change nonlocally nearby large-scale vortex structures without substantially changing local mean flows.

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Error Growth in a Whole Atmosphere Climate Model

Journal of the Atmospheric Sciences ◽

10.1175/2008jas2825.1 ◽

2009 ◽

Vol 66 (1) ◽

pp. 173-186 ◽

Cited By ~ 29

Author(s):

H-L. Liu ◽

F. Sassi ◽

R. R. Garcia

Keyword(s):

Gravity Waves ◽

Growth Rates ◽

Climate Model ◽

Initial Conditions ◽

Lower Thermosphere ◽

Physical Nature ◽

Upper Atmosphere ◽

Lower Atmosphere ◽

Finite Limit ◽

Mesosphere And Lower Thermosphere

Abstract It has been well established that the atmosphere is chaotic by nature and thus has a finite limit of predictability. The chaotic divergence of initial conditions and the predictability are explored here in the context of the whole atmosphere (from the ground to the thermosphere) using the NCAR Whole Atmosphere Community Climate Model (WACCM). From ensemble WACCM simulations, it is found that the early growth of differences in initial conditions is associated with gravity waves and it becomes apparent first in the upper atmosphere and progresses downward. The differences later become more profound on increasingly larger scales, and the growth rates of the differences change in various atmospheric regions and with seasons—corresponding closely with the strength of planetary waves. For example, in December–February the growth rates are largest in the northern and southern mesosphere and lower thermosphere and in the northern stratosphere, while smallest in the southern stratosphere. The growth rates, on the other hand, are not sensitive to the altitude where the small differences are introduced in the initial conditions or the physical nature of the differences. Furthermore, the growth rates in the middle and upper atmosphere are significantly reduced if the lower atmosphere is regularly reinitialized, and the reduction depends on the frequency and the altitude range of the reinitialization.

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Preliminary Dual-Satellite Observations of Atmospheric Gravity Waves in Airglow

Atmosphere ◽

10.3390/atmos10110650 ◽

2019 ◽

Vol 10 (11) ◽

pp. 650

Author(s):

Jia Yue ◽

Septi Perwitasari ◽

Shuang Xu ◽

Yuta Hozumi ◽

Takuji Nakamura ◽

...

Keyword(s):

Gravity Waves ◽

Near Infrared ◽

Infrared Imaging ◽

Numerical Models ◽

Space Station ◽

Upper Atmosphere ◽

Lower Atmosphere ◽

Atmospheric Gravity Waves ◽

Spectral Imager ◽

Atmospheric Gravity

Atmospheric gravity waves (AGWs) are among the important energy and momentum transfer mechanisms from the troposphere to the middle and upper atmosphere. Despite their understood importance in governing the structure and dynamics of these regions, mesospheric AGWs remain poorly measured globally, and largely unconstrained in numerical models. Since late 2011, the Suomi National Polar-orbiting Partnership (NPP) Visible/Infrared Imaging Radiometer Suite (VIIRS) day–night band (DNB) has observed global AGWs near the mesopause by virtue of its sensitivity to weak emissions of the OH* Meinel bands. The wave features, detectable at 0.75 km spatial resolution across its 3000 km imagery swath, are often confused by the upwelling emission of city lights and clouds reflecting downwelling nightglow. The Ionosphere, Mesosphere, upper Atmosphere and Plasmasphere (IMAP)/ Visible and near-Infrared Spectral Imager (VISI) O2 band, an independent measure of the AGW structures in nightglow based on the International Space Station (ISS) during 2012–2015, contains much less noise from the lower atmosphere. However, VISI offers much coarser resolution of 14–16 km and a narrower swath width of 600 km. Here, we present preliminary results of comparisons between VIIRS/DNB and VISI observations of AGWs, focusing on several concentric AGW events excited by the thunderstorms over Eastern Asia in August 2013. The comparisons point toward suggested improvements for future spaceborne airglow sensor designs targeting AGWs.

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TRACES OF HIGH SEISMIC ACTIVITY IN THE UPPERMOST SEDIMENTS OF LAKE BAIKAL, SIBERIA

Geodynamics & Tectonophysics ◽

10.5800/gt-2021-12-3-0538 ◽

2021 ◽

Vol 12 (3) ◽

pp. 544-562

Author(s):

E. G. Vologina ◽

M. Sturm ◽

Ya. B. Radziminovich

Keyword(s):

Lake Baikal ◽

Seismic Activity ◽

Rift Zone ◽

Sediment Cores ◽

Historical Earthquakes ◽

Baikal Rift Zone ◽

Seismic Events ◽

Research Activities ◽

Entire Lake ◽

South Baikal

Sedimentation in Lake Baikal is significantly affected by continuous seismic activity in the Baikal Rift Zone. Our study shows that historical earthquakes, as well as recent seismic events, considerably influenced sedimentation in this deep tectonic basin. Here we present some of the results of extensive international research activities during the period of 1996–2019. To identify traces of seismic events in the uppermost sediments (<1.5 m), short cores were recovered from many coring stations throughout the entire lake. Based on lithological descriptions, measurements of magnetic susceptibility, and concentration of inorganic and organic components, we identified earthquake indicators in the sediment cores. Impacts of historical earthquakes were traced within South Baikal (near the Sharyzhalgai Station and the Station 106-km of the Circum-Baikal railway, hereafter CBR) and Proval Bay (near the Selenga River delta).

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BAYKAL and TRANSBAIKALIA

Zemletriaseniia Severnoi Evrazii [Earthquakes in Northern Eurasia] ◽

10.35540/1818-6254.2019.22.13 ◽

2019 ◽

Cited By ~ 5

Author(s):

Valentina Melnikova ◽

N. Gileva ◽

O. Masalskii

Keyword(s):

Seismic Activity ◽

Rift Zone ◽

Baikal Rift Zone ◽

Strike Slip ◽

Focal Mechanisms ◽

Normal Faults ◽

Seismic Events ◽

High Degree ◽

South Baikal

The seismicity of Pribaikalye and Transbaikalia in 2013 is reviewed. 6706 earthquakes with КР≥5.6 were recorded there during that year. Most of them (92 %) are located in the Baikal rift zone. The high degree of clustering of seismic events is observed in South Baikal and Baikal-Muja areas. The largest earthquake with Mw=4.3 was in the Baikal-Muja area. Focal mechanisms of 47 earthquakes (КР9.6) were determined in 2013. Most of them correspond to normal faults, with strike-slip component contribution in some cases. Overall, the rate of seismic activity observed in Pribaikalye and Transbaikalia in 2013 was low.

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