Is there a quasi-biennial oscillation in tropical deep convection?

1998 ◽  
Vol 25 (3) ◽  
pp. 333-336 ◽  
Author(s):  
Christopher C. Collimore ◽  
Matthew H. Hitchman ◽  
David W. Martin
Keyword(s):  
Deep Convection ◽  
Quasi Biennial Oscillation ◽  
Tropical Deep Convection ◽  
Biennial Oscillation

scholarly journals Effects of tropical deep convection on interannual variability of tropical tropopause layer water vapor

2017 ◽  
Author(s):  
Hao Ye ◽  
Andrew E. Dessler ◽  
Wandi Yu
Keyword(s):  
Water Vapor ◽  
Interannual Variability ◽  
Deep Convection ◽  
Tropospheric Temperature ◽  
Quasi Biennial Oscillation ◽  
Tropical Tropopause Layer ◽  
Tropical Tropopause ◽  
Tropical Deep Convection ◽  
The Impact ◽  
Biennial Oscillation

Abstract. Water vapor interannual variability in the tropical tropopause layer (TTL) is investigated using satellite observations and model simulations. We breakdown the influences of the Brewer-Dobson circulation (BDC), the quasi-biennial oscillation (QBO), and the tropospheric temperature (ΔT) as a function of latitude and longitude using a 2-dimensional multivariable linear regression. This allows us to examine the spatial distribution of the impact on TTL water vapor from these physical processes. In agreement with expectation, we find that the impacts from the BDC and QBO act on TTL water vapor by changing TTL temperature. For ΔT, we find that TTL temperatures alone cannot explain the influence. We hypothesize a moistening role for the evaporation of convective ice from increased deep convection as troposphere warms. Tests with simulations from GEOSCCM and a corresponding trajectory model support this hypothesis.

The Influence of the Quasi-Biennial Oscillation on the Troposphere in Winter in a Hierarchy of Models. Part II: Perpetual Winter WACCM Runs

2011 ◽  
Vol 68 (9) ◽  
pp. 2026-2041 ◽  
Author(s):  
Chaim I. Garfinkel ◽  
Dennis L. Hartmann
Keyword(s):  
Climate Model ◽  
Deep Convection ◽  
Polar Vortex ◽  
Reanalysis Data ◽  
Quasi Biennial Oscillation ◽  
Stratospheric Polar Vortex ◽  
Thermal Wind ◽  
The North ◽  
Tropical Deep Convection ◽  
Biennial Oscillation

Abstract Experiments with the Whole Atmosphere Community Climate Model (WACCM) are used to understand the influence of the stratospheric tropical quasi-biennial oscillation (QBO) in the troposphere. The zonally symmetric circulation in thermal wind balance with the QBO affects high-frequency eddies throughout the extratropical troposphere. The influence of the QBO is strongest and most robust in the North Pacific near the jet exit region, in agreement with observations. Variability of the stratospheric polar vortex does not appear to explain the effect of the QBO in the troposphere in the model, although it does contribute to the response in the North Atlantic. Anomalies in tropical deep convection associated with the QBO appear to damp, rather than drive, the effect of the QBO in the extratropical troposphere. Rather, the crucial mechanism whereby the QBO modulates the extratropical troposphere appears to be the interaction of tropospheric transient waves with the axisymmetric circulation in thermal wind balance with the QBO. The response to QBO winds of realistic amplitude is stronger for perpetual February radiative conditions and sea surface temperatures than perpetual January conditions, consistent with the observed response in reanalysis data, in a coupled seasonal WACCM integration, and in dry model experiments described in Part I.

scholarly journals Correction to “Is there a quasi-biennial oscillation in tropical deep convection?”

2000 ◽  
Vol 27 (21) ◽  
pp. 3491-3491
Author(s):  
Christopher C. Collimore ◽  
Matthew H. Hitchman ◽  
David W. Martin
Keyword(s):  
Deep Convection ◽  
Quasi Biennial Oscillation ◽  
Tropical Deep Convection ◽  
Biennial Oscillation

scholarly journals Tropical Deep Convection Impact on Southern Winter Stationary Waves and Its Modulation by the Quasi-Biennial Oscillation

2019 ◽  
Vol 32 (21) ◽  
pp. 7453-7467 ◽  
Author(s):  
Cristina Peña-Ortiz ◽  
Elisa Manzini ◽  
Marco A. Giorgetta
Keyword(s):  
Model Simulation ◽  
Dominant Role ◽  
Deep Convection ◽  
Polar Vortex ◽  
Stationary Waves ◽  
Quasi Biennial Oscillation ◽  
Tropical Deep Convection ◽  
The Impact ◽  
Biennial Oscillation ◽  
Winter Hemisphere

Abstract The impact of tropical deep convection on southern winter stationary waves and its modulation by the quasi-biennial oscillation (QBO) have been investigated in a long (210 year) climate model simulation and in ERA-Interim reanalysis data for the period 1979–2018. Model results reveal that tropical deep convection over the region of its climatological maximum modulates high-latitude stationary planetary waves in the southern winter hemisphere, corroborating the dominant role of tropical thermal forcing in the generation of these waves. In the tropics, deep convection enhancement leads to wavenumber-1 eddy anomalies that reinforce the climatological Rossby–Kelvin wave couplet. The Rossby wave propagates toward the extratropical southern winter hemisphere and upward through the winter stratosphere reinforcing wavenumber-1 climatological eddies. As a consequence, stronger tropical deep convection is related to greater upward wave propagation and, consequently, to a stronger Brewer–Dobson circulation and a warmer polar winter stratosphere. This linkage between tropical deep convection and the Southern Hemisphere (SH) winter polar vortex is also found in the ERA-Interim reanalysis. Furthermore, model results indicate that the enhancement of deep convection observed during the easterly phase of the QBO (E-QBO) gives rise to a similar modulation of the southern winter extratropical stratosphere, which suggests that the QBO modulation of convection plays a fundamental role in the transmission of the QBO signature to the southern stratosphere during the austral winter, revealing a new pathway for the QBO–SH polar vortex connection. ERA-Interim corroborates a QBO modulation of deep convection; however, the shorter data record does not allow us to assess its possible impact on the SH polar vortex.

Responses of Tropical Deep Convection to the QBO: Cloud-Resolving Simulations

2015 ◽  
Vol 72 (9) ◽  
pp. 3625-3638 ◽  
Author(s):  
Ji Nie ◽  
Adam H. Sobel
Keyword(s):  
Large Scale ◽  
Deep Convection ◽  
Vertical Motion ◽  
Convective Precipitation ◽  
Temperature Perturbation ◽  
Quasi Biennial Oscillation ◽  
Reference Profile ◽  
Budget Analysis ◽  
Tropical Deep Convection ◽  
Sst Anomalies

Abstract Observational studies suggest that the stratospheric quasi-biennial oscillation (QBO) can modulate tropical deep convection. The authors use a cloud-resolving model with a limited domain, representing a convective column in the tropics, to study the mechanisms of this modulation. The large-scale circulation is parameterized using the weak temperature gradient (WTG) approximation, under which the parameterized large-scale vertical motion acts to relax the horizontal-mean temperature toward a specified reference profile. Temperature variations typically seen in easterly and westerly phases are imposed in the upper troposphere and lower stratosphere of this reference profile. The responses of convection are studied over different sea surface temperatures, holding the reference temperature profile fixed. This can be thought of as studying the response of convection to the QBO over different “relative SSTs” and also corresponds to different equilibrium precipitation rates in the control simulation. The equilibrium precipitation rate shows slight increases in response to a QBO easterly phase temperature perturbation over small SST anomalies and strong decreases over large SST anomalies, and vice versa for the QBO westerly phase perturbation. A column moist static energy budget analysis reveals that the QBO modulates the convective precipitation through two pathways: it changes the high-cloud properties and thus the column radiative cooling, and it alters the shape of the large-scale vertical motion and thus the efficiency of energy transport by the large-scale flow. The nonmonotonicity of the precipitation response with respect to relative SST results from the competition of these two effects.

Impacts of mineral dust on ice clouds in tropical deep convection systems

2014 ◽  
Vol 143 ◽  
pp. 64-72 ◽  
Author(s):  
Q.-L. Min ◽  
R. Li ◽  
B. Lin ◽  
E. Joseph ◽  
V. Morris ◽  
...  
Keyword(s):  
Mineral Dust ◽  
Deep Convection ◽  
Ice Clouds ◽  
Tropical Deep Convection
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