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: 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: 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: 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

scholarly journals Modal Decomposition of the Global Response to Tropical Heating Perturbations Resembling MJO

2019 ◽  
Vol 76 (5) ◽  
pp. 1457-1469 ◽  
Author(s):  
Katarina Kosovelj ◽  
Fred Kucharski ◽  
Franco Molteni ◽  
Nedjeljka Žagar
Keyword(s):  
Normal Mode ◽  
Numerical Experiments ◽  
Short Range ◽  
Kelvin Waves ◽  
Madden Julian Oscillation ◽  
Global Response ◽  
Function Decomposition ◽  
Mode Function ◽  
Response Variance ◽  
Medium Range

Abstract The paper presents four ensembles of numerical experiments that compare the response to monopole and dipole heating perturbations resembling different phases of the Madden–Julian oscillation (MJO). The results quantify the Rossby and inertio-gravity (IG) wave response using the normal-mode function decomposition. The day 3 response is characterized by about 60% variance in the IG modes, with about 85% of it belonging to the Kelvin waves. On day 14, only 10% of the response variance is due to the Kelvin waves. Although the n = 1 Rossby mode is the main contributor to the Rossby variance at all time scales, the n > 1 Rossby modes contribute over 50% of the balanced response to the MJO heating. In the short range, dipole perturbations produce a response with the maximal variance in zonal wavenumbers k = 2–3 whereas in the medium range the response maximizes at k = 1 in all experiments. Furthermore, the medium-range response to the heating perturbation mimicking MJO phase 6 is found also over Europe.

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.

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