23 rd ecrs the stratospheric polar vortex as a cause for the temporal variability of solar activity...
TRANSCRIPT
2323rdrd ECRS ECRS
The stratospheric polar vortex The stratospheric polar vortex as a cause for the temporal variability as a cause for the temporal variability of solar activity and galactic cosmic ray of solar activity and galactic cosmic ray
effects effects on the lower atmosphere circulationon the lower atmosphere circulation
S.Veretenenko, M.OgurtsovS.Veretenenko, M.Ogurtsov
Ioffe Physical-Technical Institute, Russian Academy of Ioffe Physical-Technical Institute, Russian Academy of Sciences, St.Petersburg, RussiaSciences, St.Petersburg, Russia
GCR effects on troposphere pressure in GCR effects on troposphere pressure in different epochs the large-scale atmospheric different epochs the large-scale atmospheric
circulationcirculation
0.7
-0.7-0.5
-0.4
0.60.40.4
0.4
-0.5
-0.5
-0.4
-0.5-0.4
-0.4
-0.4
-0.4
0.4
0.3
-160 -120
- 80
- 40
0
40
80
120
160
-80
-60
-40
-20
20
40
60
80
Correlation coefficients between GPH 700 hPa and NM (Climax). Period: 1982-2000
0
0.6 0.
6
-0.6
-0.5
-0.5
0.3
0.4
-0.4
Arctic front, JanuaryArctic front, July
Polar front, January
Polar front, July
Equatorial trough axis, JanuaryEquatorial trough axis, July
-0.6 -0.4 -0.2 0 0.2 0.4 0.6
-0.6-0.5
0.40.4
-0.5
-0.4-0.4
-0.5
-0.4
0.4
0.50.5
0.3
-160 -120
- 80
- 40
0
40
80
120
160
-80
-60
-40
-20
0
20
40
80
Correlation coefficients between GPH 700 hPa and NM (Climax). Period: 1953-1981
60
0.20.
3
0.4
-0.4
-0.5-0.5
0.60.5
Arctic front, January
Arctic front, July
Polar front, January
Polar front, July
Equatorial trough axis, January
Equatorial trough axis, July
-0.6 -0.4 -0.2 0 0.2 0.4 0.6
Epoch of increasing meridional circulation (C type)Epoch of increasing meridional circulation (C type)(1982-2000 гг.)(1982-2000 гг.)
Epoch of decreasing Epoch of decreasing meridional circulation meridional circulation ((C type)C type)(1953-1981 гг.)(1953-1981 гг.)
GCR increase in the minima of the 11-year cycle is accompaniedGCR increase in the minima of the 11-year cycle is accompanied
• Intensification of near-ground Arctic Intensification of near-ground Arctic anticyclonesanticyclones• Intensification of extratropical cyclogenesis Intensification of extratropical cyclogenesis at Polar fronts at Polar fronts • Weakening of the equatorial troughWeakening of the equatorial trough ((tropical cyclogenesistropical cyclogenesis))
• Weakening of near-ground Arctic Weakening of near-ground Arctic anticyclonesanticyclones•Weakening of extratropical cyclogenesis Weakening of extratropical cyclogenesis •Intensification of the equatorial troughIntensification of the equatorial trough
Veretenenko and Ogurtsov, Adv. Space Res., 2012 Veretenenko and Ogurtsov, Adv. Space Res., 2012
Time variation of SA/GCR effects on troposphere Time variation of SA/GCR effects on troposphere pressure pressure
and the evolution of the large-scale atmospheric and the evolution of the large-scale atmospheric circulationcirculation
Time variations of the Time variations of the correlation between correlation between troposphere pressure at troposphere pressure at high/middle latitudes and high/middle latitudes and sunspot numbers reveal a sunspot numbers reveal a pronouncedpronounced ~~60-year 60-year periodicityperiodicity..
Reversals ofReversals of the correlation the correlation sign at high latitudes occurred sign at high latitudes occurred in the in the 18901890ss,, the early the early 1920s1920s, , 1950s1950s and the early and the early 1980s1980s
0 0.04 0.08 0.12 0.16 0.2Frequency, yr -1
0
4
8
12
16
Sp
ectr
al d
ensi
ty
85°N
80°N
75°N
Polar region64
2336
The reversals of the sign of SA/GCR The reversals of the sign of SA/GCR effects coincide with the changes in the effects coincide with the changes in the evolution of the large-scale meridional evolution of the large-scale meridional circulation (the form C according to circulation (the form C according to Vangengeim-Girs classificationVangengeim-Girs classification). ).
1880 1900 1920 1940 1960 1980 2000Ye a rs
-0.8
-0.4
0
0.4
0.8
Co
rre
latio
n c
oe
ffici
en
t
Po lar Vortex
1880 1900 1920 1940 1960 1980 2000
40
80
120
160
W,
da
ys
120
160
200
E,
da
ys
8 0
1 0 0
1 2 0
C,
da
ys
W
E
C
0 0.04 0.08 0.12 0.16 0.2
Fre q u e n cy, yr-1
0
4
8
12
16S
pe
ctra
l po
we
r d
en
sity
63 yrs
25 yrs
(a)
(b) (c) M erid ional fo rm C
Veretenenko and Ogurtsov, Adv. Space Res., 2012Veretenenko and Ogurtsov, Adv. Space Res., 2012
The results obtained show:The results obtained show:
Regional character of SA/GCR effects on troposphere Regional character of SA/GCR effects on troposphere pressure which is determined by peculiarities of baric pressure which is determined by peculiarities of baric systems forming in the regions under study;systems forming in the regions under study;
SA/GCR effects may change the sign depending on the SA/GCR effects may change the sign depending on the time periodtime period;;
The sign of SA/GCR effects seems to be determined by The sign of SA/GCR effects seems to be determined by the evolution of the large-scale meridional circulation;the evolution of the large-scale meridional circulation;
There are long-term variations, with the period being There are long-term variations, with the period being ~60 ~60 years, of the amplitude and sign of SA/GCR effects on years, of the amplitude and sign of SA/GCR effects on troposphere pressure of high and middle latitudes troposphere pressure of high and middle latitudes
The aim of this work The aim of this work is to studyis to study
what processes may influence the evolution of what processes may influence the evolution of the circulation epochs and the sign of SA/GCR the circulation epochs and the sign of SA/GCR
effects on troposphere pressure?effects on troposphere pressure?
Main elements of the large-scale circulation of the Main elements of the large-scale circulation of the atmosphere at middle and high latitudesatmosphere at middle and high latitudes
-160
-120
- 80
- 40
0
40
80
120
160
0
20
40
60
80
GPH 200 hPa. January 2005.
1.08
1.1
1.12
1.14
1.16
1.18
1.2
1.22
1.24
x 104
-160
-120
- 80
- 40
0
40
80
120
160
0
20
40
60
80
Magnitude of temperature gradients (grad/100 km). Layer 1000-500 hPa. January 2005.
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
Polar vortexPolar vortex (cyclonic (cyclonic circulation in the circulation in the middle/upper troposphere middle/upper troposphere and stratosphere at high and stratosphere at high latitudes) latitudes) Planetary frontal zonePlanetary frontal zone (regions of high (regions of high temperature contrasts in the temperature contrasts in the troposphere)troposphere) Extratropical cyclones and Extratropical cyclones and anticyclonesanticyclones
Planetary frontal zone (areas of high Planetary frontal zone (areas of high temperature contrasts in the troposphere )temperature contrasts in the troposphere )
Polar vortex (area of low pressurePolar vortex (area of low pressureIn the upper troposphere)In the upper troposphere)
StratosphereStratosphere
-160
-120
- 80
- 40
0
40
80
120
160
0
20
40
60
80
AIR TEMPERATURE. 20 hPa. January 2005.
-79
-80 -75 -70 -65 -60 -55 -50 -45 -40 -35
1.3706
-160
-120
- 80
- 40
0
40
80
120
160
0
20
40
60
80
TEMPERATURE GRADIENT. 20 hPa. January 2005.
0.7 0.8 0.9 1 1.1 1.2 1.3C C/100 km
Troposphere Troposphere
In the stratosphere the In the stratosphere the polar vortex is seen as a polar vortex is seen as a region of low region of low temperature with temperature with enhanced temperature enhanced temperature gradients on its edges.gradients on its edges.
GCR effects on troposphere pressure GCR effects on troposphere pressure in the high-latitudinal area in the high-latitudinal area
0.70.6
0.60.5
0.40.3
-0.6
-0.5
-0.4-0.7
-0.6-0.5
0.4
0.4
-0.6
-0.5
-0.4
-0.5-0.4
-0.3
0
20
40
60
80
Correlation coefficients between GPH 700 hPa and NM (Climax). Period: 1982-2000
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
1 2 3 4 5 6
0.97
0.98
0.95
0.97
0.97
0.95
0.98
-160
-120
- 80
- 40
0
40
80
120
160
0
20
40
60
80
Confidence levels for R(GPH700,NM) according to Monte-Carlo tests.1982-2000.
0.950.9
0.9
0.9
0.9
0.9
0.9
0.950.97
0.95
0.97 0.970.95
Epoch of increasing meridional Epoch of increasing meridional circulation circulation (1982-2000)(1982-2000)
..
0.9
0.95
0.99
0.95
0.9
-160
-120
- 80
- 40
0
40
80
120
160
0
20
40
60
80
Confidence levels for R(GPH700,NM)according to Monte-Carlo tests. 1953-1981.
0.950.97
0.98
0.9
0.970.98
0.9
0.95
-0.5-0.4
-0.3
0.4
0.4 0.3
0.4
0.3
-0.3
0.3
0.2
0
20
40
60
80
Correlation coefficients between GPH 700 hPa and NM (Climax). Period: 1953-1981
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
1 2 3 4 5 6
Epoch of decreasing meridional Epoch of decreasing meridional circulation circulation (19(195353--19811981))
Most statistically Most statistically significant correlation significant correlation coefficients between coefficients between troposphere pressure and troposphere pressure and GCR are observed: GCR are observed:
InIn the high-latitudinal the high-latitudinal areaarea (independently of the (independently of the time period)time period)
atat Polar frontsPolar fronts ( (Polar Polar frontal zones) at middle frontal zones) at middle latitudes in the periods of latitudes in the periods of increasing meridional increasing meridional circulation.circulation.
0.70.6
0.60.5
0.40.3
-0.6
-0.5
-0.4-0.7
-0.6-0.5
0.4
0.4
-0.6
-0.5
-0.4
-0.5-0.4
-0.3
0
20
40
60
80
Correlation coefficients between GPH 700 hPa and NM (Climax). Period: 1982-2000
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
1 2 3 4 5 6
-0.5-0.4
-0.3
0.40.4 0.3
0.4
0.3
-0.3
0.3
0.2
0
20
40
60
80
Correlation coefficients between GPH 700 hPa and NM (Climax). Period: 1953-1981
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
1 2 3 4 5 6
-160
-120
- 80
- 40
0
40
80
120
160
0
20
40
60
80
AIR TEMPERATURE. 20 hPa. January 2005.
-79
-80 -75 -70 -65 -60 -55 -50 -45 -40 -35
1.3706
-160
-120
- 80
- 40
0
40
80
120
160
0
20
40
60
80
TEMPERATURE GRADIENT. 20 hPa. January 2005.
0.7 0.8 0.9 1 1.1 1.2 1.3C C/100 km
The area of theThe area of the polar polar vortexvortex formationformation is is an area of most an area of most significant significant correlations between correlations between troposphere troposphere pressure and GCR pressure and GCR variations variations independently on the independently on the time period and the time period and the epoch of the large-epoch of the large-scale circulationscale circulation
This suggests a possible contribution of processes taking place in the This suggests a possible contribution of processes taking place in the polar vortex to GCR effects on the lower atmosphere circulationpolar vortex to GCR effects on the lower atmosphere circulation
~~60-year cycle in the climate of the Arctic 60-year cycle in the climate of the Arctic and the polar vortex stateand the polar vortex state
~~60-60-year cycleyear cycle in the Arctic climate in the Arctic climate manifests itself as themanifests itself as the rotation of cold rotation of cold and warm epochsand warm epochs which is closely which is closely related to the polar vortex states:related to the polar vortex states: Strong vortex Strong vortex warm epoch warm epoch Weak vortex Weak vortex cold epochcold epoch
The transitions between warm and The transitions between warm and cold epochs in the Arctic detected on cold epochs in the Arctic detected on the base of sea-level temperatures the base of sea-level temperatures were foundwere found in the early 1920s, 1950s in the early 1920s, 1950s and 1980sand 1980s
Gudkovich et al., Problems of Arctic and AntarcticGudkovich et al., Problems of Arctic and Antarctic, 2009, 2009
Anomalies of mean yearly sea-level temperatures Anomalies of mean yearly sea-level temperatures at latitudes at latitudes 70-8570-85N in the Arctic.N in the Arctic.
The reversals of the sign of SA/GCR effects coincide well with the The reversals of the sign of SA/GCR effects coincide well with the transitions between cold and warm epochs in the Arctic transitions between cold and warm epochs in the Arctic corresponding to the different states of the vortexcorresponding to the different states of the vortex..
Time evolution of SA/GCR effects on troposphere pressure Time evolution of SA/GCR effects on troposphere pressure and the strength of the polar vortex according to NCEP/NCAR and the strength of the polar vortex according to NCEP/NCAR
reanalysis datareanalysis data
1950-1980 – 1950-1980 – the period of a the period of a weakweak vortex. vortex. • Decrease of pressure gradients between middle and Decrease of pressure gradients between middle and high latitudes high latitudes • Increase of stratospheric temperature in the vortex Increase of stratospheric temperature in the vortex area area • Weakening of the C form of meridional circulation.Weakening of the C form of meridional circulation.• Cold epoch in the Arctic.Cold epoch in the Arctic.
1980-2010 – 1980-2010 – the period of a the period of a strongstrong vortex vortex• Increase of pressure gradients between middle and Increase of pressure gradients between middle and high latitudeshigh latitudes• Decrease of stratospheric temperature in the vortex Decrease of stratospheric temperature in the vortex area area • Intensification of the meridional circulation C. Intensification of the meridional circulation C. • Warm epoch in the Arctic. Warm epoch in the Arctic.
The sign reversals of SA/GCR effects The sign reversals of SA/GCR effects in the 1950s and in the 1950s and 19801980s correspond s correspond to the transitions between the different to the transitions between the different vortex states.vortex states.
-0.8
-0.4
0
0.4
0.8
R (SLP, R z)
R (G PH 700, N M )
a)
-30
-20
-10
0
10
20
30
H (40-65 N )Polynom ia l fit
1880 1900 1920 1940 1960 1980 2000Years
- 2
- 1
0
1
2
T (60-90 N )P olynom ia l fit
7 0
8 0
9 0
1 0 0
1 1 0
1 2 0
C
C orrelation coeffic ient
Frequency, days
b)
H , gp.m
c)
Tem perature, K
500 hPa
50 hPad)
Thus, the Thus, the ~60-year variation~60-year variation of the amplitude and sign of of the amplitude and sign of SA/GCR SA/GCR effectseffects on troposphere pressure seems to be closely related to the on troposphere pressure seems to be closely related to the changes of the vortex strengthchanges of the vortex strength and the corresponding and the corresponding changes of changes of the large-scale atmospheric circulationthe large-scale atmospheric circulation
Strong vortex : Strong vortex : GCR increase in the 11-year cycle GCR increase in the 11-year cycle iintensificationntensification of mid-latitudinal cyclones of mid-latitudinal cyclones and polar anticyclonesand polar anticyclones
Weak vortex : Weak vortex : GCR increase in the 11-yr cycleGCR increase in the 11-yr cycle weakeningweakening of of mid-latitudinalmid-latitudinal cyclones and cyclones and polar anticyclonespolar anticyclones
A possible reason for the sign reversals of SA/GCR effects may be A possible reason for the sign reversals of SA/GCR effects may be changes in the troposphere-stratosphere couplingchanges in the troposphere-stratosphere coupling caused by different caused by different conditions for propagation of planetary waves in the periods of a conditions for propagation of planetary waves in the periods of a strong or weak vortexstrong or weak vortex.
The polar vortex state seems to play an important part in The polar vortex state seems to play an important part in the mechanism of solar-atmospheric linksthe mechanism of solar-atmospheric links
-79
0.5
12
37
11
0.5
12
3
711
15
-160
-120
- 80
- 40
0
40
80
120
160
0
20
40
60
80
Temperature. 20 hPa. January 2005.
-80
-75
-70
-65
-60
-55
-50
-45
-40
-35a)
C
The area of the vortex formation is The area of the vortex formation is characterized by characterized by low rigiditieslow rigidities, so , so GCR particles with a broad energy GCR particles with a broad energy range may precipitate here range may precipitate here including the low energy including the low energy component strongly modulated by component strongly modulated by solar activity. Ion production rate in solar activity. Ion production rate in the vortex area is higher compared the vortex area is higher compared with that at middle and low latitudeswith that at middle and low latitudes
The polar vortex location and vertical geomagnetic The polar vortex location and vertical geomagnetic cutoff rigidities (in GV) according to Shea and cutoff rigidities (in GV) according to Shea and Smart (1983).Smart (1983).
-90 -80 -70 -60 -50 -40 -30 -20Tem perature, °Ñ
1000850700
500400
300
200
150
100
70
50
30
20
10
0.4 0.8 1.2 1.6 2 2.4 2.8 3.2 3.6 4Tem perature gradient, °Ñ/100 km
0
5
10
15
20
25
30Tem peratureTem perature gradientIon-pair production ra te
0 10 20 30 40Ion-pair production rate, cm -3s -1
b)Pressure, hPa H eight, km
Monthly averaged fluxes of ionizing Monthly averaged fluxes of ionizing particles over Murmansk region (R =0.6 particles over Murmansk region (R =0.6 GV)GV)
Bazilevskaya et al., Space Sci. Rev, 2008Bazilevskaya et al., Space Sci. Rev, 2008
•The The highest values of ionizationhighest values of ionization due to GCR due to GCR are observed in the are observed in the lower part of the vortexlower part of the vortex (10-15 km) where temperature gradients at the (10-15 km) where temperature gradients at the vortex edges start increasing.vortex edges start increasing.
• The The 11-yr modulation of GCR fluxes11-yr modulation of GCR fluxes is the is the strongest at 20-25 km where the strongest at 20-25 km where the vortex is most vortex is most pronounced. pronounced.
Height dependences of the Arctic air Height dependences of the Arctic air mass characteristics in January 2005 and mass characteristics in January 2005 and the ion-pair production rate in free air at the ion-pair production rate in free air at polar latitudes (polar latitudes (R R = 0-0.6 GV)= 0-0.6 GV) according according to Bazilevskaya et al. (2008).to Bazilevskaya et al. (2008).
The vortex location is favorable for the mechanisms of solar The vortex location is favorable for the mechanisms of solar activity influence on the atmosphere circulation involving activity influence on the atmosphere circulation involving variations of GCR intensity variations of GCR intensity
Possible mechanisms of solar activity influence on the lower Possible mechanisms of solar activity influence on the lower atmosphere circulation may involve changes of the vortex atmosphere circulation may involve changes of the vortex state associated with different agents (e.g., GCR variations, state associated with different agents (e.g., GCR variations, UV fluxes)UV fluxes)
Intensification of the polar vortex in the period when it is Intensification of the polar vortex in the period when it is strong seems to contribute to an increase of temperature strong seems to contribute to an increase of temperature contrasts in tropospheric frontal zones and an intensification contrasts in tropospheric frontal zones and an intensification of extratropical cyclogenesisof extratropical cyclogenesis
Conclusions:Conclusions: The evolution of the stratospheric polar vortex The evolution of the stratospheric polar vortex plays an important plays an important
part in part in the mechanism of solar-climatic linksthe mechanism of solar-climatic links.. The detected The detected long-term oscillations of correlations long-term oscillations of correlations between between
troposphere pressure at middle and high latitudes and SA/GCR troposphere pressure at middle and high latitudes and SA/GCR characteristics seem to be closely related to characteristics seem to be closely related to the changes of the polar the changes of the polar vortex strength. vortex strength.
The vortex strength The vortex strength reveals a roughly reveals a roughly 60-year periodicity 60-year periodicity influencing influencing the large-scale atmospheric circulation and the sign of SA/GCR the large-scale atmospheric circulation and the sign of SA/GCR effects on troposphere pressure.effects on troposphere pressure.
When the vortex is strongWhen the vortex is strong, meridional processes intensify and an , meridional processes intensify and an increase of GCR fluxes results increase of GCR fluxes results in an enhancement of cyclonic in an enhancement of cyclonic activity at middle latitudes and anticyclone formation at polar activity at middle latitudes and anticyclone formation at polar latitudeslatitudes. . When the vortex is weakWhen the vortex is weak, meridional processes weaken , meridional processes weaken and and GCR effects on the development of baric systems GCR effects on the development of baric systems at middle and at middle and high latitudes high latitudes change the signchange the sign. A possible reason for the sign . A possible reason for the sign reversals may be different troposphere-stratosphere coupling during reversals may be different troposphere-stratosphere coupling during the periods of a strong and weak vortex.the periods of a strong and weak vortex.