frequency, persistence, and seasonality of … persistence, and seasonality of atmospheric...
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Frequency, persistence, and seasonality of atmospheric circulation types in European regionsMonika Cahynová (1,2), Radan Huth (1)cahynova@ufa. cas.cz
(1) Institute of Atmospheric Physics, Academy of Sciences of the Czech Republic(2) Faculty of Science, Charles University, Prague
COST733 Final Event, Vienna, 22-24 November 2010
we studied seasonal linear trends in the frequency of CTs in 1957-2002 in all catalogues from cat.1.2, all domainstotal number of CTs > 55,000comparison of objective and subjective cataloguesrelated issues
different number of CTs in individual cataloguesin each catalogue, season, and domain, we were looking for the CTs with trends significant at the 95% leveldifferent overall occurrence of individual CTs – how to compare the resulting trends?thus we calculated the percentage of DAYS occupied by CTs with significant trends in frequency
Frequency of CTs
D00
0
20
40
60
80
100
CK
ME
AN
SC
09C
KM
EA
NS
C18
CK
ME
AN
SC
27E
SLP
C09
ES
LPC
18E
SLP
C27
EZ8
50C
10E
Z850
C20
EZ8
50C
30G
WT
GW
TC10
GW
TC18
GW
TC26
KH
C09
KH
C18
KH
C27
LITA
DV
ELI
TC18
LITT
CLU
ND
LUN
DC
09LU
ND
C18
LUN
DC
27LW
T2LW
T2C
10LW
T2C
18N
NW
NN
WC
09N
NW
C18
NN
WC
27 P27
P27
C08
P27
C16
P27
C27
PC
AC
AP
CA
CA
C09
PC
AC
AC
18P
CA
CA
C27
PC
AX
TRP
CA
XTR
C09
PC
AX
TRC
18P
CA
XTR
KM
PC
AX
TRK
MC
09P
CA
XTR
KM
C18
PE
TIS
CO
PE
TIS
CO
C09
PE
TIS
CO
C18
PE
TIS
CO
C27
SA
ND
RA
SA
ND
RA
C09
SA
ND
RA
C18
SA
ND
RA
C27
SA
ND
RA
SS
AN
DR
AS
C09
SA
ND
RA
SC
18S
AN
DR
AS
C27
TPC
AV
TPC
A07
TPC
AC
09TP
CA
C18
TPC
AC
27W
LKC
733
WLK
C09
WLK
C18
WLK
C28
%
MAM JJA SON DJF
Percentage of days occupied by CTs with significant trend in frequency in selected domains
whole EuropeD07
0
20
40
60
80
100
CK
ME
AN
SC
09C
KM
EA
NS
C18
CK
ME
AN
SC
27E
SLP
C09
ES
LPC
18E
SLP
C27
EZ8
50C
10E
Z850
C20
EZ8
50C
30G
WT
GW
TC10
GW
TC18
GW
TC26
KH
C09
KH
C18
KH
C27
LITA
DV
ELI
TC18
LITT
CLU
ND
LUN
DC
09LU
ND
C18
LUN
DC
27LW
T2C
10LW
T2C
18LW
T2N
NW
NN
WC
09N
NW
C18
NN
WC
27 P27
P27
C08
P27
C16
P27
C27
PC
AC
AP
CA
CA
C09
PC
AC
AC
18P
CA
CA
C27
PC
AX
TRP
CA
XTR
C09
PC
AX
TRC
18P
CA
XTR
KM
PC
AX
TRK
MC
09P
CA
XTR
KM
C18
PE
TIS
CO
PE
TIS
CO
C09
PE
TIS
CO
C18
PE
TIS
CO
C27
SA
ND
RA
SA
ND
RA
C09
SA
ND
RA
C18
SA
ND
RA
C27
SA
ND
RA
SS
AN
DR
AS
C09
SA
ND
RA
SC
18S
AN
DR
AS
C27
TPC
AV
TPC
A07
TPC
AC
09TP
CA
C18
TPC
AC
27W
LKC
733
WLK
C09
WLK
C18
WLK
C28
%
MAM JJA SON DJF
D02
0
20
40
60
80
100
CK
ME
AN
SC
09C
KM
EA
NS
C18
CK
ME
AN
SC
27E
SLP
C09
ES
LPC
18E
SLP
C27
EZ8
50C
10E
Z850
C20
EZ8
50C
30G
WT
GW
TC10
GW
TC18
GW
TC26
KH
C09
KH
C18
KH
C27
LITA
DV
ELI
TC18
LITT
CLU
ND
LUN
DC
09LU
ND
C18
LUN
DC
27LW
T2C
10LW
T2C
18LW
T2N
NW
NN
WC
09N
NW
C18
NN
WC
27 P27
P27
C08
P27
C16
P27
C27
PC
AC
AP
CA
CA
C09
PC
AC
AC
18P
CA
CA
C27
PC
AX
TRP
CA
XTR
C09
PC
AX
TRC
18P
CA
XTR
KM
PC
AX
TRK
MC
09P
CA
XTR
KM
C18
PE
TIS
CO
PE
TIS
CO
C09
PE
TIS
CO
C18
PE
TIS
CO
C27
SA
ND
RA
SA
ND
RA
C09
SA
ND
RA
C18
SA
ND
RA
C27
SA
ND
RA
SS
AN
DR
AS
C09
SA
ND
RA
SC
18S
AN
DR
AS
C27
TPC
AV
TPC
A07
TPC
AC
09TP
CA
C18
TPC
AC
27W
LKC
733
WLK
C09
WLK
C18
WLK
C28
%
MAM JJA SON DJFD11
0
20
40
60
80
100
CK
ME
AN
SC
09C
KM
EA
NS
C18
CK
ME
AN
SC
27E
SLP
C09
ES
LPC
18E
SLP
C27
EZ8
50C
10E
Z850
C20
EZ8
50C
30G
WT
GW
TC10
GW
TC18
GW
TC26
KH
C09
KH
C18
KH
C27
LITA
DV
ELI
TC18
LITT
CLU
ND
LUN
DC
09LU
ND
C18
LUN
DC
27LW
T2C
10LW
T2C
18LW
T2N
NW
NN
WC
09N
NW
C18
NN
WC
27 P27
P27
C08
P27
C16
P27
C27
PC
AC
AP
CA
CA
C09
PC
AC
AC
18P
CA
CA
C27
PC
AX
TRP
CA
XTR
C09
PC
AX
TRC
18P
CA
XTR
KM
PC
AX
TRK
MC
09P
CA
XTR
KM
C18
PE
TIS
CO
PE
TIS
CO
C09
PE
TIS
CO
C18
PE
TIS
CO
C27
SA
ND
RA
SA
ND
RA
C09
SA
ND
RA
C18
SA
ND
RA
C27
SA
ND
RA
SS
AN
DR
AS
C09
SA
ND
RA
SC
18S
AN
DR
AS
C27
TPC
AV
TPC
A07
TPC
AC
09TP
CA
C18
TPC
AC
27W
LKC
733
WLK
C09
WLK
C18
WLK
C28
%
MAM JJA SON DJF
Scandinavia
Central Europe
E Mediterranean
HB
GW
LH
BG
WT
OG
WL
OG
WLS
LPP
EC
ZELY
PE
RR
ET
SC
HU
EE
PP
ZAM
G
Frequency of CTs
Frequency of CTsMagnitude of significant trends in the frequency of CTs in GWTC10(days per season in 1957-2002)
W SW NW C A N NE E SE SD00 -4D01 -6D02 5D03 -5D04D05D06D07D08 5D09 2 -8D10 -3D11D00D01D02D03D04 5D05D06 3D07 -2D08D09 -6D10 -2 -5 9D11
sprin
gsu
mm
er
W SW NW C A N NE E SE SD00D01 -6D02D03D04D05D06D07 -4 4D08 2D09D10D11 5 -7D00 17 -11D01D02 -3D03D04 10D05 -6D06 8 -6D07 16 -4 -7D08 14 -3 -9 -10D09D10 5 -3 -6D11 11 -8
autu
mn
win
ter
Seasonal occurrence and significant trend in occurrence of CTs in 1957-2002 (D07) - DJF
-15
-10
-5
0
5
10
15
20
0 10 20 30 40četnost typu [% dní]
tren
d [d
ny]
Seasonal occurrence and significant trend in occurrence of CTs in 1957-2002 (D07) - SON
-15
-10
-5
0
5
10
15
20
0 10 20 30 40četnost typu [% dní]
tren
d [d
ny]
Seasonal occurrence and significant trend in occurrence of CTs in 1957-2002 (D07) - JJA
-15
-10
-5
0
5
10
15
20
0 10 20 30 40četnost typu [% dní]
tren
d [d
ny]
Seasonal occurrence and significant trend in occurrence of CTs in 1957-2002 (D07) - MAM
-15
-10
-5
0
5
10
15
20
0 10 20 30 40četnost typu [% dní]
tren
d [d
ny]
objektivnísubjektivní
Seasonal frequency vs. magnitude of significant trends in frequency of CTs in Central Europe (D07)Results from all objective and all subjective classifications
spring (MAM) summer (JJA) autumn (SON) winter (DJF)
frequency of CT [% days] frequency of CT [% days] frequency of CT [% days] frequency of CT [% days]
objectivesubjective
Frequency of CTs
Persistence of CTs
persistence = length of sequence of days classified with one CTHess-Brezowsky: sudden increase in persistence in the mid-1980s – is it real or is it just an inhomogeneity?COST733 catalogue version 1.2, domains 00, 02, 04, 07, 09additional: OGWL with a minimum 3-day duration of CTs (…thanks to Paul James)applied statistics:
long-term persistence of individual types and all types combinedtime series of annual persistencelinear trends of persistencecorrelation of time series of persistence between pairs of classifications
Overall trends in persistence - whole year
-1.5-1.0-0.50.00.51.01.52.02.5
CK
ME
AN
SC
09C
KM
EA
NS
C18
CK
ME
AN
SC
27E
SLP
C09
ES
LPC
18E
SLP
C27
GW
TC10
GW
TC18
GW
TC26
KH
C09
KH
C18
KH
C27
LITA
DV
ELI
TC18
LITT
CLU
ND
C09
LUN
DC
18LU
ND
C27
LWT2
C10
LWT2
C18
LWT2
NN
WC
09N
NW
C18
NN
WC
27P
27C
08P
27C
16P
27C
27P
CA
CA
C09
PC
AC
AC
18P
CA
CA
C27
PC
AX
TRC
09P
CA
XTR
C18
PC
AX
TRK
MC
09P
CA
XTR
KM
C18
PE
TIS
CO
C09
PE
TIS
CO
C18
PE
TIS
CO
C27
SA
ND
RA
C09
SA
ND
RA
C18
SA
ND
RA
C27
SA
ND
RA
SC
09S
AN
DR
AS
C18
SA
ND
RA
SC
27TP
CA
C09
TPC
AC
18TP
CA
C27
WLK
C09
WLK
C18
WLK
C28
HB
GW
LH
BG
WT
OG
WLS
LPP
EC
ZELY
PE
RR
ET
SC
HU
EE
PP
ZAM
Glinea
r tre
nd p
er 4
4 ye
ars
[day
s]
D00 D02 D04 D07 D09
Persistence of CTs
Percentage of positive and negative trends in persistence of individual CTs in D00 - whole year
-100
-50
0
50
100
CK
ME
AN
SC
09C
KM
EA
NS
C18
CK
ME
AN
SC
27E
SLP
C09
ES
LPC
18E
SLP
C27
GW
TC10
GW
TC18
GW
TC26
KH
C09
KH
C18
KH
C27
LITA
DV
ELI
TC18
LITT
CLU
ND
C09
LUN
DC
18LU
ND
C27
LWT2
C10
LWT2
C18
LWT2
NN
WC
09N
NW
C18
NN
WC
27P
27C
08P
27C
16P
27C
27P
CA
CA
C09
PC
AC
AC
18P
CA
CA
C27
PC
AX
TRC
09P
CA
XTR
C18
PC
AX
TRK
MC
09P
CA
XTR
KM
C18
PE
TIS
CO
C09
PE
TIS
CO
C18
PE
TIS
CO
C27
SA
ND
RA
C09
SA
ND
RA
C18
SA
ND
RA
C27
SA
ND
RA
SC
09S
AN
DR
AS
C18
SA
ND
RA
SC
27TP
CA
C09
TPC
AC
18TP
CA
C27
WLK
C09
WLK
C18
WLK
C28
HB
GW
LH
BG
WT
OG
WLS
LPP
EC
ZELY
PE
RR
ET
SC
HU
EE
PP
ZAM
G
%
the sudden increase in persistence in the Hess-Brezowsky in the mid-1980 is most probably an inhomogeneityit it caused by vanishing 3-day events
0123456789
1957 1967 1977 1987 1997
[d]
HBGWL HBGWL 10 groupsOGWL-3d+ OGWL-3d+ 10 groupsOGWL OGWL 10 groups
Persistence of CTs
HBGWL Number of situations according to their length
0
10
20
30
40
50
60
70
80
90
1958
1963
1968
1973
1978
1983
1988
1993
1998
3 4
5 6
7 8
9 10
11 12
13 14
15 16
17 19
20 23
OGWL-3d+ Number of situations according to their length
0
10
20
30
40
50
60
70
80
90
100
1948
1953
1958
1963
1968
1973
1978
1983
1988
1993
1998
2003
3 4 5 6 7 8 9 10 11 1213 14 15 16 17 18 19 21 22
1985-86
Do individual classifications share a common long-term pattern of year-to-year changes in persistence?correlation of time series of annual persistence between pairs of classifications
Percentage of significant (95 % level) positive and negative correlations of annual persistence between individual classifications
0
20
40
60
80
100
CK
ME
AN
SC
09C
KM
EA
NS
C18
CK
ME
AN
SC
27E
SLP
C09
ES
LPC
18E
SLP
C27
GW
TC10
GW
TC18
GW
TC26
KH
C09
KH
C18
KH
C27
LITA
DV
ELI
TC18
LITT
CLU
ND
C09
LUN
DC
18LU
ND
C27
LWT2
C10
LWT2
C18
LWT2
NN
WC
09N
NW
C18
NN
WC
27P
27C
08P
27C
16P
27C
27P
CA
CA
C09
PC
AC
AC
18P
CA
CA
C27
PC
AX
TRC
09P
CA
XTR
C18
PC
AX
TRK
MC
09P
CA
XTR
KM
C18
PE
TIS
CO
C09
PE
TIS
CO
C18
PE
TIS
CO
C27
SA
ND
RA
C09
SA
ND
RA
C18
SA
ND
RA
C27
SA
ND
RA
SC
09S
AN
DR
AS
C18
SA
ND
RA
SC
27TP
CA
C09
TPC
AC
18TP
CA
C27
WLK
C09
WLK
C18
WLK
C28
%
D00 +D02 +D04 +D07 +D09 +D00 -D02 -D04 -D07 -D09 -
Persistence of CTs
Persistence vs. temperature anomalies: Kyselý (2007) and Kyselý and Huth (2008) found that persistent CTs are conducive to heat and cold spells, and hypothesized that the increase of persistence could lead to an increased severity of temperature extremesNow that we know that persistence is not rising, should we still be afraid of these extremes?We revisit the topic of warm CTs in summer in Central Europe, comparing the Hess-Brezowsky with its objectivized version OGWL3in the period 1961-2000
Persistence of CTs
Warm CT: mean Tavg anomaly > 1 deg.CTrends in frequency and temperature anomaly of early stages (days 1-5) and late stages (days 6+) of CTsWe found major differences between HBGWL and OGWL3Most of the warm CTs are warmer during their late stagesDifferent individual CTs actas “warm CTs” in differentparts of the study area
Persistence of CTs
Persistence of CTs
-20
-10
0
10
20
LIS
T/S
YLT
SC
HLE
SW
IGR
OS
TOC
K-
HE
LGO
LAN
DS
CH
WE
RIN
HA
MB
UR
G-
BR
EM
EN
NE
UR
UP
PIN
HA
NN
OV
ER
PO
TSD
AM
LIN
DE
NB
ER
GM
AG
DE
BU
RK
AS
SE
LG
OR
LITZ
AA
CH
EN
FIC
HTE
LBE
RH
OF
PR
AH
A-
BA
MB
ER
GW
UR
ZBU
RG
NU
RN
BE
RG
SA
AR
BR
UC
KK
AR
LSR
UH
EA
UG
SB
UR
GW
IEN
HO
HE
NP
EIS
KE
MP
TEN
ZUG
SP
ITZE
INN
SB
RU
CK
GR
AZ
tren
d of
occ
urre
nce
[day
s/40
yea
rs]
warm days 1-5 warm days 6+ warm days all
-20
-10
0
10
20
LIS
T/S
YLT
SC
HLE
SW
IGR
OS
TOC
K-
HE
LGO
LAN
DS
CH
WE
RIN
HA
MB
UR
G-
BR
EM
EN
NE
UR
UP
PIN
HA
NN
OV
ER
PO
TSD
AM
LIN
DE
NB
ER
GM
AG
DE
BU
RK
AS
SE
LG
OR
LITZ
AA
CH
EN
FIC
HTE
LBE
RH
OF
PR
AH
A-
BA
MB
ER
GW
UR
ZBU
RG
NU
RN
BE
RG
SA
AR
BR
UC
KK
AR
LSR
UH
EA
UG
SB
UR
GW
IEN
HO
HE
NP
EIS
KE
MP
TEN
ZUG
SP
ITZE
INN
SB
RU
CK
GR
AZ
tren
d of
occ
urre
nce
[day
s/40
yea
rs]
warm days 1-5 warm days 6+ warm days all
HBGWL OGWL3
Under HBGWL, warming of warm CTs is caused mainly by rising persistenceUnder OGWL3, warming is caused mainly by within-type temperature trends
-3
-2
-1
0
1
2
3
4
LIS
T/S
YLT
SC
HLE
SW
IGR
OS
TOC
K-
HE
LGO
LAN
DS
CH
WE
RIN
HA
MB
UR
G-
BR
EM
EN
NE
UR
UP
PIN
HA
NN
OV
ER
PO
TSD
AM
LIN
DE
NB
ER
GM
AG
DE
BU
RK
AS
SE
LG
OR
LITZ
AA
CH
EN
FIC
HTE
LBE
RH
OF
PR
AH
A-
BA
MB
ER
GW
UR
ZBU
RG
NU
RN
BE
RG
SA
AR
BR
UC
KK
AR
LSR
UH
EA
UG
SB
UR
GW
IEN
HO
HE
NP
EIS
KE
MP
TEN
ZUG
SP
ITZE
INN
SB
RU
CK
GR
AZ
tren
d of
Tav
g an
omal
y [º
C/4
0 ye
ars] warm days 1-5 warm days 6+ warm days all
-3
-2
-1
0
1
2
3
4
LIS
T/S
YLT
SC
HLE
SW
IGR
OS
TOC
K-
HE
LGO
LAN
DS
CH
WE
RIN
HA
MB
UR
G-
BR
EM
EN
NE
UR
UP
PIN
HA
NN
OV
ER
PO
TSD
AM
LIN
DE
NB
ER
GM
AG
DE
BU
RK
AS
SE
LG
OR
LITZ
AA
CH
EN
FIC
HTE
LBE
RH
OF
PR
AH
A-
BA
MB
ER
GW
UR
ZBU
RG
NU
RN
BE
RG
SA
AR
BR
UC
KK
AR
LSR
UH
EA
UG
SB
UR
GW
IEN
HO
HE
NP
EIS
KE
MP
TEN
ZUG
SP
ITZE
INN
SB
RU
CK
GR
AZ
tren
d of
Tav
g an
omal
y [º
C/4
0 ye
ars] warm days 1-5 warm days 6+ warm days all
comparison of classifications according to the seasonal (monthly) relative frequency of CTswe have developed several simple indices of seasonality based on monthly relative frequency of CTsDo individual classifications share a common long-term pattern of year-to-year changes in the seasonal variations of atmospheric circulation?
Seasonality of CTs
LUNDC09
0%
20%
40%
60%
80%
100%
1 2 3 4 5 6 7 8 9 101112
LITADVE
0%
20%
40%
60%
80%
100%
1 2 3 4 5 6 7 8 9 101112
GWTC10
0%
20%
40%
60%
80%
100%
1 2 3 4 5 6 7 8 9 101112
CKMEANSC09
0%
20%
40%
60%
80%
100%
1 2 3 4 5 6 7 8 9 101112
TPCAC09
0%
20%
40%
60%
80%
100%
1 2 3 4 5 6 7 8 9 101112
SANDRAC09
0%
20%
40%
60%
80%
100%
1 2 3 4 5 6 7 8 9 101112
PETISCOC09
0%
20%
40%
60%
80%
100%
1 2 3 4 5 6 7 8 9 101112
P27C08
0%
20%
40%
60%
80%
100%
1 2 3 4 5 6 7 8 9 101112month
rela
tive
freq
uenc
y
maximum seasonality
Seasonality of CTsMaximum index of seasonality
0
20
40
60
80
100
CK
ME
AN
SC
09C
KM
EA
NS
C18
CK
ME
AN
SC
27E
Z850
C10
EZ8
50C
20E
Z850
C30
ES
LPC
09E
SLP
C18
ES
LPC
27G
WTC
10G
WTC
18G
WTC
26K
HC
09K
HC
18K
HC
27LI
TAD
VE
LITC
18LI
TTC
LUN
DC
09LU
ND
C18
LUN
DC
27LW
T2C
10LW
T2C
18LW
T2P
27C
08P
27C
16P
27C
27P
CA
CA
C09
PC
AC
AC
18P
CA
CA
C27
PC
AX
TRC
09P
CA
XTR
C18
PC
AX
TRK
MC
09P
CA
XTR
KM
C18
PE
TIS
CO
C09
PE
TIS
CO
C18
PE
TIS
CO
C27
SA
ND
RA
C09
SA
ND
RA
C18
SA
ND
RA
C27
SA
ND
RA
SC
09S
AN
DR
AS
C18
SA
ND
RA
SC
27TP
CA
C09
TPC
AC
18TP
CA
C27
WLK
C09
WLK
C18
WLK
C28
HB
GW
LH
BG
WT
OG
WL
OG
WLS
LPP
EC
ZELY
PE
RR
ET
SC
HU
EE
PP
ZAM
G
D00D01D02D03D04D05D06D07D08D09D10D11
Month with maximum frequency of type with maximum seasonality
1
2
3
4
5
6
7
8
9
10
11
12
CK
ME
AN
SC
09C
KM
EA
NS
C18
CK
ME
AN
SC
27E
Z850
C10
EZ8
50C
20E
Z850
C30
ES
LPC
09E
SLP
C18
ES
LPC
27G
WTC
10G
WTC
18G
WTC
26K
HC
09K
HC
18K
HC
27LI
TAD
VE
LITC
18LI
TTC
LUN
DC
09LU
ND
C18
LUN
DC
27LW
T2C
10LW
T2C
18LW
T2P
27C
08P
27C
16P
27C
27P
CA
CA
C09
PC
AC
AC
18P
CA
CA
C27
PC
AX
TRC
09P
CA
XTR
C18
PC
AX
TRK
MC
09P
CA
XTR
KM
C18
PE
TIS
CO
C09
PE
TIS
CO
C18
PE
TIS
CO
C27
SA
ND
RA
C09
SA
ND
RA
C18
SA
ND
RA
C27
SA
ND
RA
SC
09S
AN
DR
AS
C18
SA
ND
RA
SC
27TP
CA
C09
TPC
AC
18TP
CA
C27
WLK
C09
WLK
C18
WLK
C28
HB
GW
LH
BG
WT
OG
WL
OG
WLS
LPP
EC
ZELY
PE
RR
ET
SC
HU
EE
PP
ZAM
G
D00D01D02D03D04D05D06D07D08D09D10D11
seasonality of the most seasonal CT
Seasonality of CTsAverage index of seasonality
0
20
40
60
80
100
CK
ME
AN
SC
09C
KM
EA
NS
C18
CK
ME
AN
SC
27E
Z850
C10
EZ8
50C
20E
Z850
C30
ES
LPC
09E
SLP
C18
ES
LPC
27G
WTC
10G
WTC
18G
WTC
26K
HC
09K
HC
18K
HC
27LI
TAD
VE
LITC
18LI
TTC
LUN
DC
09LU
ND
C18
LUN
DC
27LW
T2C
10LW
T2C
18LW
T2P
27C
08P
27C
16P
27C
27P
CA
CA
C09
PC
AC
AC
18P
CA
CA
C27
PC
AX
TRC
09P
CA
XTR
C18
PC
AX
TRK
MC
09P
CA
XTR
KM
C18
PE
TIS
CO
C09
PE
TIS
CO
C18
PE
TIS
CO
C27
SA
ND
RA
C09
SA
ND
RA
C18
SA
ND
RA
C27
SA
ND
RA
SC
09S
AN
DR
AS
C18
SA
ND
RA
SC
27TP
CA
C09
TPC
AC
18TP
CA
C27
WLK
C09
WLK
C18
WLK
C28
HB
GW
LH
BG
WT
OG
WL
OG
WLS
LPP
EC
ZELY
PE
RR
ET
SC
HU
EE
PP
ZAM
G
D00D01D02D03D04D05D06D07D08D09D10D11
Sum of weighted seasonality of all types
0,0
0,2
0,4
0,6
0,8
1,0
CK
ME
AN
SC
09C
KM
EA
NS
C18
CK
ME
AN
SC
27E
Z850
C10
EZ8
50C
20E
Z850
C30
ES
LPC
09E
SLP
C18
ES
LPC
27G
WTC
10G
WTC
18G
WTC
26K
HC
09K
HC
18K
HC
27LI
TAD
VE
LITC
18LI
TTC
LUN
DC
09LU
ND
C18
LUN
DC
27LW
T2C
10LW
T2C
18LW
T2P
27C
08P
27C
16P
27C
27P
CA
CA
C09
PC
AC
AC
18P
CA
CA
C27
PC
AX
TRC
09P
CA
XTR
C18
PC
AX
TRK
MC
09P
CA
XTR
KM
C18
PE
TIS
CO
C09
PE
TIS
CO
C18
PE
TIS
CO
C27
SA
ND
RA
C09
SA
ND
RA
C18
SA
ND
RA
C27
SA
ND
RA
SC
09S
AN
DR
AS
C18
SA
ND
RA
SC
27TP
CA
C09
TPC
AC
18TP
CA
C27
WLK
C09
WLK
C18
WLK
C28
HB
GW
LH
BG
WT
OG
WL
OG
WLS
LPP
EC
ZELY
PE
RR
ET
SC
HU
EE
PP
ZAM
G
D00D01D02D03D04D05D06D07D08D09D10D11
seasonality of each CT is weighted by its overall relative frequency
Seasonality of CTs
Do individual classifications share a common long-term pattern of year-to-year changes in the seasonal variations of atmospheric circulation?correlation of time series of maximum seasonality index between pairs of classifications
Percentage of significant (95 % level) positive and negative correlations of annual maximum seasonality between individual classifications
0
20
40
60
80
100
CK
ME
AN
SC
09C
KM
EA
NS
C18
CK
ME
AN
SC
27E
Z850
C10
EZ8
50C
20E
Z850
C30
ES
LPC
09E
SLP
C18
ES
LPC
27G
WTC
10G
WTC
18G
WTC
26K
HC
09K
HC
18K
HC
27LI
TAD
VE
LITC
18LI
TTC
LUN
DC
09LU
ND
C18
LUN
DC
27LW
T2C
10LW
T2C
18LW
T2P
27C
08P
27C
16P
27C
27P
CA
CA
C09
PC
AC
AC
18P
CA
CA
C27
PC
AX
TRC
09P
CA
XTR
C18
PC
AX
TRK
MC
09P
CA
XTR
KM
C18
PE
TIS
CO
C09
PE
TIS
CO
C18
PE
TIS
CO
C27
SA
ND
RA
C09
SA
ND
RA
C18
SA
ND
RA
C27
SA
ND
RA
SC
09S
AN
DR
AS
C18
SA
ND
RA
SC
27TP
CA
C09
TPC
AC
18TP
CA
C27
WLK
C09
WLK
C18
WLK
C28
%
D00 +D02 +D04 +D07 +D09 +D00 -D02 -D04 -D07 -D09 -
Conclusions
Systematic circulation changes in the ERA-40 period were only found in winter
These reflect the strengthening of the NAO
Persistence of CTs does not bear any systematic trends
The Hess-Brezowsky catalogue is biased in terms of persistence
Long-term variations of persistence and seasonality are not uniform in the individual classifications
References
Cahynová M., Huth R. (2009): Long-term trends in the frequency ofatmospheric circulation types in European regions (poster).EGU General Assembly
Cahynová M., Huth R. (2009): Enhanced lifetime of atmospheric circulationtypes over Europe: fact or fiction? Tellus A 61: 407–416.
Cahynová M., Huth R. (2010): Seasonal variations in the frequency ofatmospheric circulation types in European regions (poster).EGU General Assembly
Cahynová M., Huth R. (2010): The influence of persistence of atmosphericcirculation on temperature anomalies revisited (poster).EGU General Assembly
Cahynová M. (2010): The influence of long-term changes of atmosphericcirculation on observed trends of surface climatic elements in the CzechRepublic and EuropePhD thesis to be defended on December 14, 2010