On the
QBO-Solar-Relationship
throughout the Year
Karin Labitzke,
Institut für Meteorologie,
Freie Universität Berlin
SORCE-Sedona-Sep-2011.ppt
Today, I want to tell you about the
importance of the QBO and of the Sun
for the understanding of the variability of
the stratosphere in summer and in winter.
2
Vertical meridional
sections of the
standard deviations
of temperatures
(upper panel)
and heights (lower
panel)
JUL
<1.3 K
< 1K
Temp (K)
<1K
for JULY
1948 – 2007; n=59 y
Height
< 40m
(Labitzke and van Loon,
1999)
3
1953
Quasi-Biennial Oscillation
QBO (1953 – 2011)
Time- height section of monthly
mean zonal winds (m/s) at
equatorial stations:
Canton Island (3°S / 172°W)
(Jan 1953 – Aug 1967);
Gan/Maledive Islands (1°S /73°E)
(Sep 1967 – Dec 1975);
Singapore (1°N /104°E)
(since Jan 1976).
Isopleths are at 10 m/s intervals,
westerlies are shaded ;
(updated from Naujokat 1986).
(grey = west; white = east)
4
The Quasi - Biennial Oscillation (1993 – 2011)
QBO-definition for the winter: (50+40hPa in Jan+Feb) / 4;
(Holton and Tan, 1980); grey = west wind, white = east wind
5
Values of the Solar Constant of Radiation (calories)
for the Period 1905 – 1912, (Abbot et al.,1913)
(general understanding at the time: in solar maximum less radiation because
of many spots (dirty) and in minimum more radiation because of clean face6
of the sun)
Percentage UV Radiation Differences
between Solar Maxima and Minima
Solar Maxima:
more UV radiation
more UV = more Ozone
in the stratosphere
7
Data from Lean et al. , 1997
(positively correlated with the
UV part of the solar spectrum)
Monthly mean (blue) and smoothed (red), positively
8
correlated with UV part of the solar spectrum
Today, there is general agreement that
the variable sun is responsible
for a large part of the variability of the
temperatures and winds,observed
especially in the stratosphere over the
tropics and subtropics, in summer,
but the phase of the QBO
must be considered, too.
9
all
Time series of the 10.7 cm solar flux
(red lines);
detrended 30-hPa temperatures
(blue lines) in July, at the grid point
20S/57.5 W, Campo Grande/Brazil
r = correlation coefficients
r = 0.91
east
upper panel = all data, n=43 years;
middle panel = only years
in the east phase of the
QBO, n = 20 years;
west
lower panel = only years in the
west phase of the QBO, n=23 years;
(50+40 hPa)/2 is used for July.
(NCEP/NCAR: 1968-2010)
Labitzke and Kunze, JASTP, 2011)
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HOUSTON /
TEXAS
ALL
30°N /95°W
EAST
r = 0.83
WEST
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Correlations
Differences: solar max-min
30 hPa
ALL
EAST
max=0.93
WEST
JULY:
red:
corr.>0.4
(blue=temp. diff. > 1K)
12
3
Correlations (red = > 0.4)
delta T (°C): solar max –13min
32~km
shading is +/- 1
standard deviation
+ 3.5 K
DELTA T: solar max – solar min
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JULY
Correlations
Temp.Diff. max - min
blue = >1K
r=0.93
AUG
r=0.89
SEP
r=0.83
all are
30hPa
and
QBO/EAST
OCT
r=0.79
red=
corr.>0.4
NCEP/NCAR,
1968-2009,
15
n = 42 years
JUL
33
OCT
16
QBO- east
wind
is weaker in
solar max
because of the
anomalous
westwind;
similarly:
QBO-west
wind is weaker
in solar max
because of the
anomalous east
wind
Maps of 30-hPa height differences (geopot.m) in July
between solar max and solar min.
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EAST
WEST
eastwind
u-diff =
-13 m/s
r = - 0.6
Scatter diagrams of the zonal wind (m/s) over the
equator at (40+50 hPa)/2 in July (absolute values),
against the 10.7 cm solar flux; period: 1953-2010;
left: east phase of the QBO, right: winds in the west
phase. (Data set FU-Berlin, Labitzke et al., 2002)
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Equator
Vertical profiles of the differences between solar max and solar min of
the mean zonal wind (m/s) in July. (Grey shading indicates the range of
+/- 1 standard dev.) Data: NCEP/NCAR re-analyses, 1968-2010.
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So far, I concentrated on the Northern
Summer, because I think that the solar
signal is very clear and convincing during
this time of year.
I am turning now to the Northern Winter.
Here we are dealing with the Arctic Polar
Vortex and with the Major Midwinter
Warmings. They are responsible for the
tele-connections between the Arctic
and the Tropics.
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SO
Cold event
Warm event
QBO Westphase
Eastphase
SUN Solar min
Solar max
cold and strong
(Labitzke and
warm and weak
van Loon, 1987)
cold and strong (Holton and Tan, 1980;
warm and weak Data:1963-1978, n = 16)
like QBO
(Labitzke + van Loon,
opposite to QBO
1987 – 2006)
Different forcings influencing the stratospheric
polar vortex during the northern winters
21
22
Arctic versus Tropics: r= -0.66
CH
P
A
E
E
E
E E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E
E = QBO eastphase
E
E
E
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red = warm event - SO
blue = cold event - SO
all: n = 59
r = 0.19
P
Ch
CH
A
A
l
min
l
max
no correlation
with 11-year
solar cycle
Tropical volcanoes
W: Agung March 1963
E: Chichon March 1982
24
E: Pinatubo June 1991
11
n(all) = 70 winters
Feb 2011: Solar min; QBO = West,
= cold, strong vortex; n = 39
25
+11
+
5 strongest MMWs
in
east min
nodal point
lines:
~ 30S and ~ 55N
in both cases
-8
5 coldest winters
in
west min
90S
90N
Deviations of the zonal mean temperatures (K) in (Jan+Feb)/2
from the long-term mean (1968 through 2002);
(shading larger than 1 (2) standard deviations)
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east/min:
5 strongest
+ 11 K MMWs
-
Composites of
~
~
Temperature
west/max:
Anomalies
5 strongest
MMWs
+8K
(Jan+Feb)/2
~
~
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Conclusion for the Winter
•The QBO and 11-year Sun-Spot Cycle (SSC) explain a
significant portion of the variance of the winter monthly
values of Arctic temperatures, winds, and geopotential
heights.
•The behavior of the Arctic stratosphere is strongly
related to the QBO phase and to the SSC, yet other
factors such as internal variance also play an important
role.
•This emphasizes the probabilistic nature of forecasting
Arctic stratosphere behavior.
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Thank you for your attention
29
Labitzke and van Loon, 1999
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