scholarly journals Vertical structure and physical processes of the Madden-Julian oscillation: Synthesis and summary

2015 ◽  
Vol 120 (10) ◽  
pp. 4671-4689 ◽  
Author(s):  
Nicholas P. Klingaman ◽  
Xianan Jiang ◽  
Prince K. Xavier ◽  
Jon Petch ◽  
Duane Waliser ◽  
...  
Keyword(s):  
Vertical Structure ◽  
Madden Julian Oscillation ◽  
Physical Processes

scholarly journals Vertical structure and physical processes of the Madden-Julian oscillation: Exploring key model physics in climate simulations

2015 ◽  
Vol 120 (10) ◽  
pp. 4718-4748 ◽  
Author(s):  
Xianan Jiang ◽  
Duane E. Waliser ◽  
Prince K. Xavier ◽  
Jon Petch ◽  
Nicholas P. Klingaman ◽  
...  
Keyword(s):  
Vertical Structure ◽  
Madden Julian Oscillation ◽  
Physical Processes ◽  
Climate Simulations

scholarly journals Vertical structure and physical processes of the Madden-Julian Oscillation: Biases and uncertainties at short range

2015 ◽  
Vol 120 (10) ◽  
pp. 4749-4763 ◽  
Author(s):  
Prince K. Xavier ◽  
Jon C. Petch ◽  
Nicholas P. Klingaman ◽  
Steve J. Woolnough ◽  
Xianan Jiang ◽  
...  
Keyword(s):  
Short Range ◽  
Vertical Structure ◽  
Madden Julian Oscillation ◽  
Physical Processes

scholarly journals Vertical structure and physical processes of the Madden-Julian oscillation: Linking hindcast fidelity to simulated diabatic heating and moistening

2015 ◽  
Vol 120 (10) ◽  
pp. 4690-4717 ◽  
Author(s):  
Nicholas P. Klingaman ◽  
Steven J. Woolnough ◽  
Xianan Jiang ◽  
Duane Waliser ◽  
Prince K. Xavier ◽  
...  
Keyword(s):  
Vertical Structure ◽  
Diabatic Heating ◽  
Madden Julian Oscillation ◽  
Physical Processes

Convective Momentum Transport Associated with the Madden–Julian Oscillation Based on a Reanalysis Dataset

2015 ◽  
Vol 28 (14) ◽  
pp. 5763-5782 ◽  
Author(s):  
Ji-Hyun Oh ◽  
Xianan Jiang ◽  
Duane E. Waliser ◽  
Mitchell W. Moncrieff ◽  
Richard H. Johnson
Keyword(s):  
Vertical Structure ◽  
Vertical Motion ◽  
Momentum Transport ◽  
Minor Role ◽  
Wind Component ◽  
Madden Julian Oscillation ◽  
Subgrid Scale ◽  
Free Atmosphere ◽  
Reanalysis Dataset ◽  
Convective Momentum Transport

Abstract A better understanding of multiscale interactions within the Madden–Julian oscillation (MJO), including momentum exchanges, is critical for improved MJO prediction skill. In this study, convective momentum transport (CMT) associated with the MJO is analyzed based on the NOAA Climate Forecast System Reanalysis (CFSR). A three-layer vertical structure associated with the MJO, as previously suggested in the mesoscale momentum tendency profile based on global cloud-resolving model simulations, is evident in the subgrid-scale momentum tendency from the CFSR. Positive (negative) subgrid-scale momentum tendency anomalies are found near the surface, negative (positive) anomalies are found in the low to midtroposphere, and positive (negative) anomalies in the upper troposphere are found within and to the west (east) of the MJO convection. This tends to damp the MJO circulation in the free atmosphere, while enhancing MJO winds near the surface. In addition, it could also reduce the MJO eastward propagation speed and lead to the backward tilt with height in the observed MJO structure through a secondary circulation near the MJO center. Further analyses illustrate that this three-layer vertical structure in subgrid-scale momentum tendency largely balances the grid-scale momentum transport of the zonal wind component u, mainly through the transport of seasonal mean u by the MJO-scale vertical motion. Synoptic-scale systems, which were previously proposed to be essential for the u-momentum transport of the MJO, however, are found to play a minor role for the total grid-scale momentum tendency. The above momentum tendency structure is also confirmed with the ECMWF analysis for the Year of Tropical Convection (YOTC) that lends confidence to these above results based on the CFSR.

The Tropical Madden–Julian Oscillation and the Global Wind Oscillation

2009 ◽  
Vol 137 (5) ◽  
pp. 1601-1614 ◽  
Author(s):  
Klaus Weickmann ◽  
Edward Berry
Keyword(s):  
Phase Space ◽  
Winter Season ◽  
Oscillatory Behavior ◽  
Madden Julian Oscillation ◽  
Physical Processes ◽  
Similar Frequency ◽  
Planetary Scale ◽  
The Pacific ◽  
The Pacific Ocean

Abstract The global wind oscillation (GWO) is a subseasonal phenomenon encompassing the tropical Madden–Julian oscillation (MJO) and midlatitude processes like meridional momentum transports and mountain torques. A phase space is defined for the GWO following the approach of Wheeler and Hendon for the MJO. In contrast to the oscillatory behavior of the MJO, two red noise processes define the GWO. The red noise spectra have variance at periods that bracket 30–60 or 30–80 days, which are bands used to define the MJO. The correlation between the MJO and GWO is ∼0.5 and cross spectra show well-defined, coherent phase relations in similar frequency bands. However, considerable independent variance exists in the GWO. A basic dynamical distinction occurs in the direction of midlatitude wave energy dispersion, being predominantly meridional during a MJO and zonal during the GWO. This is primarily a winter season feature centered over the Pacific Ocean. A case study during April–May 2007 focuses on the GWO and two ∼30-day duration orbits with extreme anomalies in GWO phase space. The MJO phase space projections for the same time were irregular and, it is argued, partially driven by mountain torques and meridional transports. The case study reveals that multiple physical processes and time scales act to create slowly evolving planetary-scale circulation and tropical convection anomalies.

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