Investigation of seasonal and interannual variations of internal gravity wave intensity in the thermosphere over Saint Santin

1994 ◽  
Vol 99 (A4) ◽  
pp. 6297 ◽  
Author(s):  
Nikolai M. Gavrilov ◽  
Arthur D. Richmond ◽  
François Bertin ◽  
M. Lafeuille
Keyword(s):  
Gravity Wave ◽  
Internal Gravity Wave ◽  
Wave Intensity ◽  
Interannual Variations ◽  
Seasonal And Interannual Variations

On parametric instabilities of finite-amplitude internal gravity waves

1982 ◽  
Vol 119 ◽  
pp. 367-377 ◽  
Author(s):  
J. Klostermeyer
Keyword(s):  
Gravity Wave ◽  
Internal Gravity Wave ◽  
Maximum Growth ◽  
Numerical Approach ◽  
Internal Gravity Waves ◽  
Resonant Interaction ◽  
Finite Amplitude ◽  
Interaction Diagram ◽  
Parametric Instabilities ◽  
Boussinesq Fluid

The equations describing parametric instabilities of a finite-amplitude internal gravity wave in an inviscid Boussinesq fluid are studied numerically. By improving the numerical approach, discarding the concept of spurious roots and considering the whole range of directions of the Floquet vector, Mied's work is generalized to its full complexity. In the limit of large disturbance wavenumbers, the unstable disturbances propagate in the directions of the two infinite curve segments of the related resonant-interaction diagram. They can therefore be classified into two families which are characterized by special propagation directions. At high wavenumbers the maximum growth rates converge to limits which do not depend on the direction of the Floquet vector. The limits are different for both families; the disturbance waves propagating at the smaller angle to the basic gravity wave grow at the larger rate.

scholarly journals Seasonal and interannual variations of top-of-atmosphere irradiance and cloud cover over polar regions derived from the CERES data set

2006 ◽  
Vol 33 (19) ◽  
Author(s):  
Seiji Kato ◽  
Norman G. Loeb ◽  
Patrick Minnis ◽  
Jennifer A. Francis ◽  
Thomas P. Charlock ◽  
...  
Keyword(s):  
Cloud Cover ◽  
Polar Regions ◽  
Interannual Variations ◽  
Data Set ◽  
Seasonal And Interannual Variations

scholarly journals Interannual dynamics in intensity of mesoscale hydroxyl nightglow variations over Almaty

2018 ◽  
Vol 4 (2) ◽  
pp. 63-68 ◽  
Author(s):  
А. Попов ◽  
A. Popov ◽  
Николай Гаврилов ◽  
Nikolay Gavrilov ◽  
А. Андреев ◽  
...  
Keyword(s):  
Gravity Waves ◽  
Emission Intensity ◽  
Rotational Temperature ◽  
Internal Gravity Waves ◽  
Average Intensity ◽  
Interannual Variations ◽  
Average Temperature ◽  
Monthly Average ◽  
Seasonal And Interannual Variations

The method of digital difference filters is applied to the data analysis of SATI observations of hydroxyl nightglow intensity and rotational temperature at altitudes 85–90 km over Almaty (43°03' N, 76°58' E), Kazakhstan, in 2010–2017. We examine seasonal and interannual variations in monthly average values and standard deviations of variations with periods 0.4–5.4 hrs, which may be associated with internal gravity waves in the mesopause region. The monthly average temperature near the mesopause has a maximum in winter and a minimum in June. The monthly average intensity has an additional maximum in June. Standard deviation of mesoscale rotational temperature variations and characteristics of internal gravity waves are maximum in spring and autumn. The spring maximum of mesoscale OH emission intensity variations is shifted to June. Interannual variations and multi-year trends of OH rotational temperature and emission intensity may differ in detail. This may be connected with seasonal and long-term variations in the complex system of the photochemical processes, which produce the OH nightglow.

scholarly journals Seasonal and interannual variations in the nitrogen cycle in the Arabian Sea

2014 ◽  
Vol 11 (20) ◽  
pp. 5733-5747 ◽  
Author(s):  
T. Rixen ◽  
A. Baum ◽  
B. Gaye ◽  
B. Nagel
Keyword(s):  
Indian Ocean ◽  
Nitrogen Cycle ◽  
Arabian Sea ◽  
Equatorial Indian Ocean ◽  
Global Ocean ◽  
Interannual Variations ◽  
Minimum Zone ◽  
Induced Changes ◽  
Seasonal And Interannual Variations ◽  
Sw Monsoon

Abstract. The Arabian Sea plays an important role in the marine nitrogen cycle because of its pronounced mid-water oxygen minimum zone (OMZ) in which bio-available nitrate (NO3−) is reduced to dinitrogen gas (N2). As the nitrogen cycle can respond fast to climate-induced changes in productivity and circulation, the Arabian Sea sediments are an important palaeoclimatic archive. In order to understand seasonal and interannual variations in the nitrogen cycle, nutrient data were obtained from the literature published prior to 1993, evaluated, and compared with data measured during five expeditions carried out in the framework of the Joint Global Ocean Flux Study (JGOFS) in the Arabian Sea in 1995 and during a research cruise of RV Meteor in 2007. The data comparison showed that the area characterized by a pronounced secondary nitrite maximum (SNM) was by 63% larger in 1995 than a similarly determined estimate based on pre-JGOFS data. This area, referred to as the core of the denitrifying zone, showed strong seasonal and interannual variations driven by the monsoon. During the SW monsoon, the SNM retreated eastward due to the inflow of oxygen-enriched Indian Ocean Central Water (ICW). During the NE monsoon, the SNM expanded westward because of the reversal of the current regime. On an interannual timescale, a weaker SW monsoon decreased the inflow of ICW from the equatorial Indian Ocean and increased the accumulation of denitrification tracers by extending the residence time of water in the SNM. This is supported by palaeoclimatic studies showing an enhanced preservation of accumulative denitrification tracers in marine sediments in conjunction with a weakening of the SW monsoon during the late Holocene.

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