%0 Journal Article %1 Nishimoto2017Influence %A Nishimoto, Eriko %A Yoden, Shigeo %D 2017 %I American Meteorological Society %J J. Atmos. Sci. %K stratosphere climate dynamics MJO QBO %R 10.1175/jas-d-16-0205.1 %T Influence of the stratospheric Quasi-Biennial Oscillation on the Madden-Julian Oscillation during austral summer %U http://dx.doi.org/10.1175/jas-d-16-0205.1 %X AbstractInfluence of the stratospheric quasi-biennial oscillation (QBO) on the Madden-Julian Oscillation (MJO) and its statistical significance are examined for austral summer (DJF) in the neutral ENSO events during 1979?2013. The amplitude of the OLR-based MJO index (OMI) is typically larger in the easterly phase of the QBO at 50 hPa (E-QBO phase) than in the westerly (W-QBO) phase. Daily composite analyses are performed by focusing on Phase 4 of the OMI, when the active convective system is located over the eastern Indian Ocean through the Maritime Continent. The composite OLR anomaly shows larger negative value and slower eastward-propagation with prolonged period of the active convection in the E-QBO phase than in the W-QBO phase. Statistically significant differences of the MJO activities between the QBO phases also exist with dynamical consistency in the divergence of horizontal wind, the vertical wind, the moisture, the precipitation, and the 100-hPa temperature. A conditional sampling analysis is also performed by focusing on the most active convective region for each day, irrespective of the MJO amplitude and phase. Composite vertical profiles of the conditionally sampled data over the most active convective region reveal lower temperature and static stability around the tropopause in the E-QBO phase than in the W-QBO phase, which indicates more favorable to develop deep convection. This feature is more prominent and extends into lower levels in the upper troposphere over the most active convective region than other tropical regions. Composite longitude-height sections show similar features of the large-scale convective system associated with the MJO, including a vertically propagating Kelvin response.

@article{Nishimoto2017Influence, abstract = {AbstractInfluence of the stratospheric quasi-biennial oscillation (QBO) on the Madden-Julian Oscillation (MJO) and its statistical significance are examined for austral summer (DJF) in the neutral ENSO events during 1979?2013. The amplitude of the OLR-based MJO index (OMI) is typically larger in the easterly phase of the QBO at 50 hPa (E-QBO phase) than in the westerly (W-QBO) phase. Daily composite analyses are performed by focusing on Phase 4 of the OMI, when the active convective system is located over the eastern Indian Ocean through the Maritime Continent. The composite OLR anomaly shows larger negative value and slower eastward-propagation with prolonged period of the active convection in the E-QBO phase than in the W-QBO phase. Statistically significant differences of the MJO activities between the QBO phases also exist with dynamical consistency in the divergence of horizontal wind, the vertical wind, the moisture, the precipitation, and the 100-hPa temperature. A conditional sampling analysis is also performed by focusing on the most active convective region for each day, irrespective of the MJO amplitude and phase. Composite vertical profiles of the conditionally sampled data over the most active convective region reveal lower temperature and static stability around the tropopause in the E-QBO phase than in the W-QBO phase, which indicates more favorable to develop deep convection. This feature is more prominent and extends into lower levels in the upper troposphere over the most active convective region than other tropical regions. Composite longitude-height sections show similar features of the large-scale convective system associated with the MJO, including a vertically propagating Kelvin response.}, added-at = {2018-06-18T21:23:34.000+0200}, author = {Nishimoto, Eriko and Yoden, Shigeo}, biburl = {https://www.bibsonomy.org/bibtex/2b0f813a5578ff60c3683e505ae560050/pbett}, citeulike-article-id = {14251495}, citeulike-linkout-0 = {http://journals.ametsoc.org/doi/abs/10.1175/JAS-D-16-0205.1}, citeulike-linkout-1 = {http://dx.doi.org/10.1175/jas-d-16-0205.1}, day = 12, doi = {10.1175/jas-d-16-0205.1}, interhash = {7a8d501634ff2784b96014c8069eb6ce}, intrahash = {b0f813a5578ff60c3683e505ae560050}, journal = {J. Atmos. Sci.}, keywords = {stratosphere climate dynamics MJO QBO}, month = jan, posted-at = {2017-01-13 12:13:30}, priority = {2}, publisher = {American Meteorological Society}, timestamp = {2018-06-22T18:36:55.000+0200}, title = {Influence of the stratospheric Quasi-Biennial Oscillation on the Madden-Julian Oscillation during austral summer}, url = {http://dx.doi.org/10.1175/jas-d-16-0205.1}, year = 2017 }