Barotropic-Baroclinic Instability of Mean Zonal Wind During Summer Monsoon

1978 ◽  
pp. 1449-1461
Author(s):  
J. Shukla
Keyword(s):  
Summer Monsoon ◽  
Zonal Wind ◽  
Baroclinic Instability

Stratospheric zonal wind and temperature in relation to summer monsoon rainfall over India

2000 ◽  
Vol 67 (3-4) ◽  
pp. 115-121
Author(s):  
S. D. Bansod ◽  
K. D. Prasad ◽  
S. V. Singh
Keyword(s):  
Summer Monsoon ◽  
Zonal Wind ◽  
Monsoon Rainfall ◽  
Summer Monsoon Rainfall

scholarly journals Quasi-Biennial Oscillation in Stratospheric Zonal Wind and Indian Summer Monsoon

1985 ◽  
Vol 113 (8) ◽  
pp. 1421-1424 ◽  
Author(s):  
B. K. Mukherjee ◽  
K. Indira ◽  
R. S. Reddy ◽  
Bh V. Ramana Murty
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Zonal Wind ◽  
Quasi Biennial Oscillation ◽  
Biennial Oscillation

scholarly journals Meridional Rossby Wave Generation and Propagation in the Maintenance of the Wintertime Tropospheric Double Jet

2016 ◽  
Vol 73 (5) ◽  
pp. 2179-2201 ◽  
Author(s):  
Amanda K. O’Rourke ◽  
Geoffrey K. Vallis
Keyword(s):  
Zonal Wind ◽  
Momentum Flux ◽  
Baroclinic Instability ◽  
Atmospheric Model ◽  
Mean Flow ◽  
Wind Maximum ◽  
Short Waves ◽  
Instability Theory ◽  
Distinct Features ◽  
Two Jets

Abstract The eddy-driven and subtropical jets are two dynamically distinct features of the midlatitude upper-troposphere circulation that are often merged into a single zonal wind maximum. Nonetheless, the potential for a distinct double-jet state in the atmosphere exists, particularly in the winter hemisphere, and presents a unique zonal-mean flow with two waveguides and an interjet region with a weakened potential vorticity gradient upon which Rossby waves may be generated, propagate, reflect, and break. The authors investigate the interaction of two groups of atmospheric waves—those with wavelengths longer and shorter than the deformation radius—within a double-jet mean flow in an idealized atmospheric model. Patterns of eddy momentum flux convergence for long and short waves differ greatly. Short waves behave following classic baroclinic instability theory such that their eddy momentum flux convergence is centered at the eddy-driven jet core. Long waves, on the other hand, reveal strong eddy momentum flux convergence along the poleward flank of the eddy-driven jet and within the interjet region. This pattern is enhanced when two jets are present in the zonal-mean zonal wind.

scholarly journals Effect of latitudinally displaced gravity wave forcing in the lower stratosphere on the polar vortex stability

2019 ◽  
Author(s):  
Nadja Samtleben ◽  
Christoph Jacobi ◽  
Petr Pišoft ◽  
Petr Šácha ◽  
Aleš Kuchař
Keyword(s):  
Refractive Index ◽  
Gravity Wave ◽  
Zonal Wind ◽  
Polar Region ◽  
Middle Atmosphere ◽  
Negative Refractive Index ◽  
Baroclinic Instability ◽  
Polar Vortex ◽  
Circulation Model ◽  
The Impact

Abstract. In order to investigate the impact of a locally confined gravity wave (GW) hotspot, a sensitivity study based on simulations of the middle atmosphere circulation during northern winter was performed with a nonlinear, mechanistic, global circulation model. To this end, for the hotspot region we selected a fixed longitude range in the East Asian region (120° E–170° E) and a latitude range from 22.5° N–52.5° N between 18 km and 30 km, which was then shifted northward in steps of 5°. For the southernmost hotspots, we observe a decreased stationary planetary wave (SPW) 1 activity in the upper stratosphere/lower mesosphere, i.e. less SPWs 1 are propagating upwards. These GW hotspots are leading to a negative refractive index inhibiting SPW propagation at midlatitudes. The decreased SPW 1 activity is connected with an increased zonal mean zonal wind at lower latitudes. This in turn decreases the meridional potential vorticity gradient (qy) from midlatitudes towards the polar region. A reversed qy indicates local baroclinic instability which generates SPWs 1 in the polar region, where we observe a strong positive Eliassen-Palm (EP) divergence. Thus, the EP flux is increasing towards the polar stratosphere (corresponding to enhanced SPW 1 amplitudes) where the SPWs 1 are breaking and the zonal mean zonal wind is decreasing. Thus, the local GW forcing is leading to a displacement of the polar vortex towards lower latitudes. The effect of the local baroclinic instability indicated by the reversed qy also produces SPWs 1 in the lower mesosphere. The effect on the dynamics in the middle atmosphere by GW hotspots which are located northward of 50° N is negligible because the refractive index of the atmosphere is strongly negative in the polar region. Thus, any changes in the SPW activity due to the local GW forcing are quite ineffective.

Study of tropical tropospheric and lower stratospheric zonal wind variability in the context of dry and wet Indian summer monsoon years

2019 ◽  
Vol 53 (5-6) ◽  
pp. 3691-3701
Author(s):  
V. K. Mini ◽  
K. S. Hosalikar ◽  
N. Haridasan ◽  
Kunal Kausik
Keyword(s):  
Summer Monsoon ◽  
Indian Summer Monsoon ◽  
Zonal Wind ◽  
Wind Variability

Baroclinic instability of the zonal wind

1964 ◽  
Vol 2 (1) ◽  
pp. 155 ◽  
Author(s):  
John W. Miles
Keyword(s):  
Zonal Wind ◽  
Baroclinic Instability
Sign in / Sign up

Export Citation Format

Share Document