Abstract
The Quasi-Biennial Oscillation (QBO) dominates the interannual
variability in the tropical lower stratosphere and is characterized by
the descent of alternating easterly and westerly zonal winds. The QBO
impact on tropical clouds and convection has received great attention in
recent years due to its implications for weather and climate. In this
study, a 15-year record of high vertical resolution observations from
CALIPSO are used to document the QBO impact on equatorial (10°S-10°N)
clouds. Observations from radio occultations, the CERES instrument, and
the ERA5 reanalysis are also used to document the QBO impact on
temperature, radiative energy budget, and zonal wind. It is shown that
the QBO impact on zonal mean equatorial cloud fraction has a strong
seasonality. The strongest cloud fraction response to the QBO occurs in
boreal spring and early summer extending down to ~12 km
and results in a significant longwave cloud radiative effect anomaly.
The seasonality of the cloud fraction changes is synchronized with those
of temperature and zonal wind in the tropical upper troposphere.