On The Relationship between the QBO and Tropical Deep Convection

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Abstract
The height and amount of tropical deep convection are examined for a correlation with the stratospheric quasi-biennial oscillation (QBO). A new 23-yr record of outgoing longwave radiation (OLR) and a corrected 17-yr record of the highly reflective cloud (HRC) index are used as measures of convection. When binned by phase of the QBO, zonal means and maps of OLR and HRC carry a QBO signal. The spatial patterns of the maps highlight the QBO signal of OLR and HRC in typically convective regions. Spectral analysis of zonal mean OLR and HRC near the equator reveals significant peaks at QBO frequencies. Rotated empirical orthogonal function (REOF) analysis is used to determine if ENSO variations of convection are aliased into the observed QBO signals. Some analyses are repeated using the OLR record after ENSO REOF modes have been removed, yielding very similar results compared to the original analyses. It appears that the QBO signal is distinct from the ENSO signal, although the relative brevity of the ... Abstract The height and amount of tropical deep convection are examined for a correlation with the stratospheric quasi-biennial oscillation (QBO). A new 23-yr record of outgoing longwave radiation (OLR) and a corrected 17-yr record of the highly reflective cloud (HRC) index are used as measures of convection. When binned by phase of the QBO, zonal means and maps of OLR and HRC carry a QBO signal. The spatial patterns of the maps highlight the QBO signal of OLR and HRC in typically convective regions. Spectral analysis of zonal mean OLR and HRC near the equator reveals significant peaks at QBO frequencies. Rotated empirical orthogonal function (REOF) analysis is used to determine if ENSO variations of convection are aliased into the observed QBO signals. Some analyses are repeated using the OLR record after ENSO REOF modes have been removed, yielding very similar results compared to the original analyses. It appears that the QBO signal is distinct from the ENSO signal, although the relative brevity of the ...