Jim Angell’s contributions to
understanding the QBO
Jim Angell’s contributions to
understanding the QBO
Jim Angell’s contributions to
understanding the QBO
QBO !
discovery
of QBO
discovery
of QBO
Angell and
Korshover
1962, 1963
Meridional structure of QBO
from Angell and Korshover, 1963
Equatorial QBO derived from
radiosondes and rockets
Baldwin et al., 2001
Schematic of global QBO
Baldwin et al., 2001
Angell and
Korshover (1964)
coin the term
‘Quasi-Biennial
Oscillation’
Naming the QBO was not easy...
kind-of biennial oscillation
almost biennial oscillation
not quite biennial oscillation
somewhat biennial oscillation
quasi-biennial oscillation
50 hPa
temps
note
out-of-phase
between
tropics and
midlats
QBO temperature signal in lower stratosphere
derived from regression with MSU4
Snapshot of temperatures and meridional circulation
associated with the QBO
February
1994
out-of-phase
vertical
structure
note extension
into winter midlats
Equatorial waves
and the QBO
midlats
power
spectra
subtropics
tropics
strong peak at 10-15 days
Idealized wave-mean flow
interaction in QBO
Kelvin waves only propagate
in background easterly winds
Kelvin waves observed during easterly QBO winds
zonal wind
eddy
power
spectra
QBO effects on
‘centers of action’
Surface signal of QBO
Baldwin et al., 2001
Holton-Tan effect
Holton-Tan effect (composited QBO E-W)
observations
1964-1996
SKYHI
simulation
(48 years)
Meridional structure of QBO
from Angell and Korshover, 1963
evidence of
Holton-Tan
effect
Ozone QBO
out of phase
between tropics
and midlats
Column ozone from TOMS
total
interannual
variability
QBO
component
Vertical structure of ozone QBO at equator
2-cell
structure
QBO signal in nitrogen dioxide (NO2)
QBO and
stratospheric
water vapor
stratospheric
water vapor
tropical tropopause
temperature
QBO variations in stratospheric water vapor
from HALOE satellite data, 1991-2003
Deseasonalized
anomalies
Vertical propagation of QBO anomalies
(interannual ‘tape recorder’)
Stratospheric H2O anomalies are consistent
with tropical tropopause temperature changes
HALOE H2O
anomalies
tropical
tropopause
temperature
anomalies
Jim Angell’s contributions span all aspects of the QBO.
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global structure and propagation
ozone
equatorial waves
coupling with troposphere
tropopause and stratospheric H2O
Much of this original research is still relevant today!
QBO
Happy Birthday Jim!