scholarly journals Impact of the Northern Hemisphere extratropics on the skill in predicting the Madden Julian Oscillation

2010 ◽  
Vol 37 (23) ◽  
pp. n/a-n/a ◽  
Author(s):  
F. Vitart ◽  
T. Jung
Keyword(s):  
Northern Hemisphere ◽  
Madden Julian Oscillation

scholarly journals Subseasonal midlatitude prediction skill following Quasi-Biennial Oscillation and Madden–Julian Oscillation activity

2020 ◽  
Vol 1 (1) ◽  
pp. 247-259
Author(s):  
Kirsten J. Mayer ◽  
Elizabeth A. Barnes
Keyword(s):  
Northern Hemisphere ◽  
Rossby Waves ◽  
Prediction Skill ◽  
Lead Times ◽  
Madden Julian Oscillation ◽  
Quasi Biennial Oscillation ◽  
Weather Forecasts ◽  
The Pacific ◽  
Environmental Prediction ◽  
Biennial Oscillation

Abstract. The Madden–Julian Oscillation (MJO) is known to force extratropical weather days to weeks following an MJO event through excitation of stationary Rossby waves, also referred to as tropical–extratropical teleconnections. Prior research has demonstrated that this tropically forced midlatitude response leads to increased prediction skill on subseasonal to seasonal (S2S) timescales. Furthermore, the Quasi-Biennial Oscillation (QBO) has been shown to possibly alter these teleconnections through modulation of the MJO itself and the atmospheric basic state upon which the Rossby waves propagate. This implies that the MJO–QBO relationship may affect midlatitude circulation prediction skill on S2S timescales. In this study, we quantify midlatitude circulation sensitivity and prediction skill following active MJOs and QBOs across the Northern Hemisphere on S2S timescales through an examination of the 500 hPa geopotential height field. First, a comparison of the spatial distribution of Northern Hemisphere sensitivity to the MJO during different QBO phases is performed for European Centre for Medium-Range Weather Forecasts (ECMWF) ERA-Interim reanalysis and ECMWF and the National Centers for Environmental Prediction (NCEP) hindcasts. Secondly, differences in prediction skill in ECMWF and NCEP hindcasts are quantified following MJO–QBO activity. In both hindcast systems, we find that regions across the Pacific, North America, and the Atlantic demonstrate an enhanced MJO impact on prediction skill during strong QBO periods with lead times of 1–4 weeks compared to MJO events during neutral QBO periods.

scholarly journals Subseasonal Midlatitude Prediction Skill Following QBO-MJO Activity

2019 ◽  
Author(s):  
Kirsten J. Mayer ◽  
Elizabeth A. Barnes
Keyword(s):  
Spatial Distribution ◽  
North America ◽  
Northern Hemisphere ◽  
Rossby Waves ◽  
Prediction Skill ◽  
Height Field ◽  
Madden Julian Oscillation ◽  
Quasi Biennial Oscillation ◽  
The Pacific ◽  
Biennial Oscillation

Abstract. The Madden-Julian Oscillation (MJO) is known to force extratropical weather days-to-weeks following an MJO event through excitation of stationary Rossby waves, tropical-extratropical teleconnections. Prior research has demonstrated that this tropically forced midlatitude response leads to increased prediction skill on subseasonal to seasonal (S2S) timescales. Furthermore, the Quasi-Biennial Oscillation (QBO) has been shown to possibly alter these teleconnections through modulation of the MJO itself and the atmospheric basic state upon which the Rossby waves propagate. This implies that the MJO-QBO relationship may affect midlatitude circulation prediction skill on S2S timescales. In this study, we quantify midlatitude circulation sensitivity and prediction skill following active MJOs and QBOs across the Northern Hemisphere on S2S timescales through an examination of the 500 hPa geopotential height field. First, a comparison of the spatial distribution of Northern Hemisphere sensitivity to the MJO during different QBO phases is performed for ERA-Interim reanalysis and ECMWF and NCEP hindcasts. Secondly, differences in prediction skill in ECMWF and NCEP hindcasts are quantified following MJO-QBO activity. We find that regions across the Pacific, North America and the Atlantic exhibit increased prediction skill following MJO-QBO activity, but these regions are not always collocated with the locations most sensitive to the MJO under a particular QBO state. Both hindcast systems demonstrate enhanced prediction skill 7–14 days following active MJO events during strong QBO periods compared to MJO events during neutral QBO periods.

scholarly journals The Influence of the Madden–Julian Oscillation on Northern Hemisphere Winter Blocking

2016 ◽  
Vol 29 (12) ◽  
pp. 4597-4616 ◽  
Author(s):  
Stephanie A. Henderson ◽  
Eric D. Maloney ◽  
Elizabeth A. Barnes
Keyword(s):  
Northern Hemisphere ◽  
North Atlantic ◽  
Weather Conditions ◽  
Boreal Winter ◽  
Madden Julian Oscillation ◽  
Central Pacific ◽  
The West ◽  
Rossby Wave Breaking ◽  
The North ◽  
East Pacific

Abstract The persistent and quasi-stationary nature of atmospheric blocking is associated with long-lasting extreme weather conditions that influence much of the Northern Hemisphere during boreal winter. The Madden–Julian oscillation (MJO) has been previously shown to influence important factors for blocking, including Rossby wave breaking and the North Atlantic Oscillation (NAO). However, the extent to which the MJO influences blocking across the Northern Hemisphere is not yet fully understood. Utilizing a two-dimensional blocking index, composites of North Pacific, North Atlantic, and European blocking are generated relative to MJO phase. In the west and central Pacific, all MJO phases demonstrate significant changes in blocking, particularly at high latitudes. A significant decrease in east Pacific and Atlantic blocking occurs following phase 3 of the MJO, characterized by enhanced convection over the tropical East Indian Ocean and suppressed convection in the west Pacific. The opposite-signed MJO heating during phase 7 is followed by a significant increase in east Pacific and Atlantic blocking. A significant decrease in European blocking follows MJO phase 4, with an increase after phase 6. The phase 6 European blocking is hypothesized to result from two preexisting conditions: 1) an anomalous anticyclone over the Atlantic and 2) a preceding negative Pacific–North American (PNA) pattern initialized and influenced by MJO heating.

The Madden–Julian Oscillation and Its Impact on Northern Hemisphere Weather Predictability

2004 ◽  
Vol 132 (6) ◽  
pp. 1462-1471 ◽  
Author(s):  
Charles Jones ◽  
Duane E. Waliser ◽  
K. M. Lau ◽  
W. Stern
Keyword(s):  
Northern Hemisphere ◽  
Madden Julian Oscillation

scholarly journals Effect of Madden–Julian Oscillation Occurrence Frequency on the Interannual Variability of Northern Hemisphere Stratospheric Wave Activity in Winter

2018 ◽  
Vol 31 (13) ◽  
pp. 5031-5049 ◽  
Author(s):  
Feiyang Wang ◽  
Wenshou Tian ◽  
Fei Xie ◽  
Jiankai Zhang ◽  
Yuanyuan Han
Keyword(s):  
Interannual Variability ◽  
Northern Hemisphere ◽  
Wave Train ◽  
Wave Activity ◽  
Occurrence Frequency ◽  
Boreal Winter ◽  
High Latitudes ◽  
Madden Julian Oscillation ◽  
Flux Divergence ◽  
P Flux

This study uses reanalysis datasets and numerical experiments to investigate the influence of the occurrence frequency of the individual phases of the Madden–Julian oscillation (MJO) on the interannual variability of stratospheric wave activity in the middle and high latitudes of the Northern Hemisphere during boreal winter [November–February (NDJF)]. Our analysis reveals that the occurrence frequency of MJO phase 4 in winter is significantly positively correlated with the interannual variability of the Eliassen–Palm (E–P) flux divergence anomalies in the northern extratropical stratosphere; that is, higher (lower) occurrence frequency of MJO phase 4 corresponds to weaker (stronger) upward wave fluxes and increased (decreased) E–P flux divergence anomalies in the middle and upper stratosphere at mid-to-high latitudes, which implies depressed (enhanced) wave activity accompanied by a stronger (weaker) polar vortex in that region. The convection anomalies over the Maritime Continent related to MJO phase 4 excite a Rossby wave train that propagates poleward to middle and high latitudes, and is in antiphase with the climatological stationary waves of wavenumber 1 at middle and high latitudes. As the spatial distribution of the convection anomalies during MJO phase 7 has an almost opposite, but weaker, pattern to that during MJO phase 4, the occurrence frequency of MJO phase 7 has an opposite and weaker effect on the northern extratropical stratosphere to MJO phase 4. However, the other MJO phases (1, 2, 3, 5, 6, and 8) cannot significantly influence the northern extratropical stratosphere because the wave responses in these phases are neither totally in nor out of phase with the background stationary wavenumber 1.

scholarly journals Impact of the Madden–Julian Oscillation on Wintertime Precipitation in Canada

2010 ◽  
Vol 138 (10) ◽  
pp. 3822-3839 ◽  
Author(s):  
Hai Lin ◽  
Gilbert Brunet ◽  
Ruping Mo
Keyword(s):  
Standard Deviation ◽  
Indian Ocean ◽  
Northern Hemisphere ◽  
West Coast ◽  
Intraseasonal Variability ◽  
Tropical Convection ◽  
Western Pacific ◽  
Madden Julian Oscillation ◽  
The West ◽  
Precipitation Anomalies

Abstract Based on the adjusted daily total precipitation data at Canadian stations and the Climate Prediction Center Merged Analysis of Precipitation (CMAP) data during the most recent 30 Northern Hemisphere winters, the connection between the tropical convection of the Madden–Julian oscillation (MJO) and the intraseasonal variability of precipitation in Canada is investigated. The dominant convection patterns associated with the MJO are represented by the two leading modes of the empirical orthogonal function (EOF) analysis that is applied to the pentad outgoing longwave radiation (OLR) in the equatorial Indian Ocean and western Pacific. The first EOF mode is characterized by a single convection center near the Maritime Continent, whereas the second EOF has an east–west dipole structure with enhanced precipitation over the Indian Ocean and reduced convective activity over the tropical western Pacific. Lagged regression analysis reveals significant precipitation anomalies in Canada associated with the tropical convection of the MJO. Above-normal precipitation starts to occur in the west coast of Canada one pentad after a positive EOF2 phase. In the next two pentads, positive precipitation anomalies extend to a large area of south Canada. At the same time, the northeast region experiences reduced precipitation. For strong MJO events when the principal component of EOF2 exceeds its standard deviation, the precipitation anomaly in the west coast of Canada can reach about 20%–30% of its standard deviation of pentad-to-pentad variability. A linearized global primitive equation model is utilized to assess the cause of the intraseasonal variability in the Northern Hemisphere extratropics and its influence on North American weather associated with the tropical heating of the MJO.

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