The Sudden Stratospheric Warming Events in the Antarctic in 2024
Geophysical Research Letters,
Год журнала:
2025,
Номер
52(7)
Опубликована: Апрель 2, 2025
Abstract
In
July
and
August
2024,
two
consecutive
stratospheric
sudden
warming
(SSW)
events
(termed
SW07
SW08)
occurred
over
Antarctic,
both
featuring
a
rapid
17°C
temperature
rise
at
10
hPa
significant
polar
vortex
(SPV)
deceleration.
the
earliest
winter
time
of
year
recorded
in
satellite
era
(1979
to
present).
The
study
found
that,
strong
blocking
highs
affected
via
nonlinear
planetary
wave
prior
SW07,
substantial
sea
ice
loss
Antarctic
Ross
Sea
Amundsen
likely
created
favorable
conditions
for
formation
these
highs.
Furthermore,
preconditioning
significantly
amplified
intensity
waves.
A
downward‐propagating
negative
Southern
Annular
Mode
(SAM)
signal
after
supported
highs,
creating
circulation
perturbations
SW08.
addition,
enhanced
ozone
transport
from
low
latitudes
pole
during
SW08
contributed
recovery.
Язык: Английский
Effect of stratospheric temperature perturbation on the onset of Ural blocking events in winter
Quarterly Journal of the Royal Meteorological Society,
Год журнала:
2025,
Номер
unknown
Опубликована: Май 2, 2025
Abstract
The
impact
of
stratospheric
temperature
uncertainty
on
ural
blocking
(UB)
onset
is
investigated
by
utilizing
the
Open
Integrated
Forecasting
System
model.
results
reveal
that
optimal
initial
perturbation
obtained
conditional
nonlinear
(CNOP)
approach
could
obviously
suppress
UB
onset,
leading
to
weakening
or
even
collapse
UB.
This
contains
multiple‐scale
signals
mainly
located
in
upper
stratosphere
and
upstream
sector.
Further
diagnosis
indicates
develops
causes
anomalous
Eliassen–Palm
(E‐P)
flux
propagating
downward
into
troposphere.
planetary
wave
activity
further
contributes
tropospheric
energy
divergence.
Then,
an
enhanced
meridional
gradient
zonal
winds
appear
Ural
its
adjacent
sectors.
Moreover,
sector
dominated
increased
potential
vorticity
gradient.
Eventually,
weakened
during
phase.
different
scales
explored.
Numerical
show
perturbations
at
calculated
via
CNOP
method
clearly
onset.
It
noted
these
have
similar
effects
shows
with
spatial
distributions
tend
evolve
specific
planetary‐scale
perturbations.
above
are
key
factors
explaining
analogous
These
emphasize
notable
role
which
deepens
our
understanding
stratosphere–troposphere
coupling.
contribute
implementation
targeted
observations
improve
predictions.
Язык: Английский
Local wave-activity analysis of atmospheric blocks in the Northern Hemisphere winter
Authorea (Authorea),
Год журнала:
2024,
Номер
unknown
Опубликована: Апрель 29, 2024
Atmospheric
blocking
entails
a
persistent,
anomalous
meandering
of
the
jet
stream
that
disrupts
eastward
migration
transient
eddies
in
midlatitudes.Here
we
analyze
large
number
(and
blocking-like)
events
Northern
Hemisphere
winter
with
ERA5
reanalysis
through
lens
vertically-averaged
wave-activity
budget.By
applying
feature
tracking
algorithm,
large-valued
anomalies
persist
for
4
days
or
longer
at
given
location
are
identified
as
blocks,
and
block-centered
composites
constructed
budget
lifecycle
blocks.The
share
commonly
recognized
features
blocking.The
majority
persistent
occur
clusters
collocated
quasi-stationary
ridge
associated
Atlantic
Pacific
storm
track.Frequency
blocks
is
higher
(lower)
regions
where
'carrying
capacity'
lower
(higher).A
very
low
carrying
capacity
waves
leads
to
population
over
Europe.The
composite
shows
convergence
(divergence)
zonal
flux
dominates
during
onset
(decay)
phase
block,
while
eddy-induced
wind
plays
crucial
role
suppressing
maturation
period.Our
finding
broadly
supports
'traffic
jam'
hypothesis
Nakamura
Huang
common
mechanism
block
formation,
although
there
vast
diversity
actual
manifestation
individual
blocks.
Язык: Английский