south american climate dynamics - a general view tércio ambrizzi department of atmospheric sciences...
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SOUTH AMERICAN CLIMATE SOUTH AMERICAN CLIMATE DYNAMICS - A GENERAL VIEWDYNAMICS - A GENERAL VIEW
Tércio AmbrizziDepartment of Atmospheric Sciences
University of São Paulo
1ST IBERO-AMERICAN WORKSHOP ON CLIMATE DYNAMICS, CLIMATE CHANGE AND REGIONAL
CLIMATE MODELINGSão Paulo, Brazil
August 2007
Wind vector at high levels
Water vapor
DJF Main Observed and Simulated Global Teleconnection Patterns
JJA Main Observed and Simulated Global Teleconnection Patterns
TROPICAL CONVECTION AND ROSSBY WAVE GENESIS
Madden e Julian Oscillation and the generation of Rossby Wave
OLR
Wind Vector at 250 hPa
Intraseasonal Variability (MJO)
Composite evolution of 200-hPa velocity potential anomalies associated with MJO events and points of origin of tropical disturbances that developed into hurricanes or typhoons.
Precipitation anomaly
composites over the tropical Brazil associated to MJO
events
(mm)(Souza and Ambrizzi 2006)
Daily Meridional Wind Anomaly (250 hPa)
Rossby waves
Life cycle between 6 and 14+ days
(Average between 40S – 50S)
RAY TRACING - SACZ MODE - NORTH
10/20 days
20/30 days
30/70 days (Ferraz 2004)
OLR and wavenumbers 3, 4 e and 5 for each trajectory
ZCN 30/70DIA -20
200 hPa
850 hPa
ZCN 30/70DIA -18
200 hPa
850 hPa
ZCN 30/70DIA -16
200 hPa
850 hPa
ZCN 30/70DIA -14
200 hPa
850 hPa
ZCN 30/70DIA -12
200 hPa
850 hPa
ZCN 30/70DIA -10
200 hPa
850 hPa
ZCN 30/70DIA -08
200 hPa
850 hPa
ZCN 30/70DIA -06
200 hPa
850 hPa
ZCN 30/70DIA -04
200 hPa
850 hPa
ZCN 30/70DIA -02
200 hPa
850 hPa
ZCN 30/70DIA -01
200 hPa
850 hPa
ZCN 30/70DIA +0
200 hPa
850 hPa
ZCN 30/70DIA +01
200 hPa
850 hPa
ZCN 30/70DAY +02
200 hPa
850 hPa
(Ferraz 2004)
South Atlantic Convergence South Atlantic Convergence Zone Event – 21 a 28/01/1997Zone Event – 21 a 28/01/1997
Courtesy by Leila V. Carvalho
Day 21
Day 24
Day 22
Day 23
South Atlantic Convergence South Atlantic Convergence Zone Event – ContinueZone Event – Continue
Day 25
Day 28
Day 26
Day 27
Conceptual model of the SALLJ physical environment during the wet season (Marengo et al. 2004 - JC)
SALLJEX SALLJEX
Enhanced precipitation gauge network
NOAA/P-3 Missions
PIBALS Radiosondes
EXTREME PRECIPITATION EVENTS AND LLJ
1° Case: EPE + LLJ
2° Case: EPE + LLJ
3° Case: EPE + LLJ
4° Case: LLJ without EPE over the areas A1, A2 or A3
Weykamp (2006)
Divergence and Moisture flux integrated in the vertical
Weykamp (2006)
Some examples of each case for the 1998 summer
GOES 04/02/98 06Z
2
2) 04/02 LLJ (06 e 12Z) + EPE (A2)
GOES 21/02/98 06Z
3
3) 21/01 LLJ (06 e 12Z) + EPE (A3)
GOES 19/02/98 06Z
1) 19/02 LLJ (06Z) + EPE (A1)
1
4) 17/01 LLJ (12Z) without EPE
4
GOES 17/01/98 12Z
Weykamp (2006)
ATMOSPHERIC CIRCULATION SCHEMATIC PICTURES DURING CANONICAL EL NIÑO AND LA NIÑA
CANONICAL EL NIÑO
CANONICAL LA NIÑA
(Ambrizzi et al 2004)
INTER-EL NIÑOS VARIABILITY
I = (Xi - Xi)/i
ENSO episodes and the South American Regional Precipitation
Seasonal Standardized
index for the austral
summer (DJF) and
autumn (MAM)
were calculated for the
precipitation over key-
areas of South
America and the SSTa
over the Niño 1.2, 3,
3.4 and 4(Ambrizzi and Souza, 2003)
El Niño episodes and the South American Regional Precipitation during 1950-1990
(g)
-2,5
-1,5
-0,5
0,5
1,5
2,5
3,5
4,5
Ecuador/P eru
(f)
-2,5-1,5-0,50,51,52,53,54,5
Altiplano
(e)
-2,5-1,5-0,50,51,52,53,54,5
SE South America
(d)
-2,5-1,5-0,50,51,52,53,54,5
SACZ
(c)
-2,5-1,5-0,50,51,52,53,54,5
NE Brazil
(b)
-2,5-1,5-0,50,51,52,53,54,5
E Amazon
(a)
-2
-1
0
1
2
3
4
Niño 1+2 Niño 3 Niño 3+4 Niño 4
Niños SSTa
E Amazon
NE Brazil
SACZ
SE South America
Altiplano
Ecuador Peru
La Niña episodes and the South American Regional Precipitation during 1950-1990
(a)
-2
-1
0
1
2
3
4
Niño 1+2 Niño 3 Niño 3+4 Niño 4
(b)
-2,5-1,5-0,50,51,52,53,54,5
E Amazon
(c)
-2,5-1,5-0,50,51,52,53,54,5
NE Brazil
(d)
-2,5-1,5-0,50,51,52,53,54,5
SACZ
(e)
-2,5-1,5-0,50,51,52,53,54,5
SE South America
(f)
-2,5-1,5-0,50,51,52,53,54,5
Altiplano
(g)
-2,5
-1,5
-0,5
0,5
1,5
2,5
3,5
4,5
Ecuador/P eru
Niñas SSTa
E Amazon
NE Brazil
SACZ
SE South America
Altiplano
Ecuador Peru
SLC – PACIFIC BOXES - DEC - MAY – EL NIÑO
CB
E GSVD
(Coelho, Uvo and Ambrizzi, 2002 – TAC)
SSTa for 4 EL NIÑO EVENTS
El Niño 82/83 El Niño 86/87
El Niño 91/92 El Niño 97/98
Average over 4 events
(Drumond e Ambrizzi, 2003)
OMEGA ANOMALY
(Magaña e Ambrizzi 2005)
DJF ZONAL WIND AT 250 hPa
STREAMFUNCION ANOMALY AND RAY TRACING FOR 4 EL NIÑO EVENTS
Anomaly of Ψ
To identify the leading teleconnection patterns in the atmospheric circulation, Empirical Orthogonal Function (EOF) was applied to the monthly mean 700-hPa height anomalies poleward of 20° latitude for the Southern Hemisphere, for the period 1979 to 2000.
The loading pattern of AAO is defined as the first leading mode from the EOF analysis.
Monthly AAO indices are constructed by projecting the monthly mean 700-hPa height anomalies onto the leading EOF mode. Both time series are normalized by the standard deviation of the monthly index (1979-2000 base period).
DefinitionDefinition
AAO Positive FaseAAO Positive FaseClimate Prediction CenterClimate Prediction Center
Composites of SST and 200 hPa zonal wind (U200LF):Low-Frequency ( Retained Periods: above 365 days)
Negative AAO Phase Positive AAO Phase
U200U200LFLF U200U200LFLF
SSTSSTLFLF SSTSSTLFLF
(Carvalho, Jones, Ambrizzi, 2005 – JC)
Teleconnection Patterns of U200 (Wallace and Gutzler 1981)(The strongest negative correlation with grid points from 90S – 40S )
NEGATIVENEGATIVE
POSITIVEPOSITIVE
DIFFERENCEDIFFERENCE
Equatorward shift of the Subtropical Jet
Weakening Polar Jet
Strengthening of the Polar Jet Poleward shift
subtropical jet
Westerly jets can act as Rossby waveguides for propagation from tropics to midlatitudes
(Carvalho, Jones, Ambrizzi, 2005 – JC)
Precipitation AnomalyPrecipitation Anomaly (NCEP)
Summer Autumn Winter Spring
-3 -2.7-2.4-2.1-1.8-1.5-1.2-0.9-0.6-0.30 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3
-80 -70 -60 -50 -40 -30 -20
-55
-50
-45
-40
-35
-30
-25
-20
-15
AAO (-) Summer
-3 -2.7-2.4-2.1-1.8-1.5-1.2-0.9-0.6-0.30 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3
-80 -70 -60 -50 -40 -30 -20
-55
-50
-45
-40
-35
-30
-25
-20
-15
AAO (-) Autumn
-3 -2.7-2.4-2.1-1.8-1.5-1.2-0.9-0.6-0.30 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3
-80 -70 -60 -50 -40 -30 -20
-55
-50
-45
-40
-35
-30
-25
-20
-15
AAO (-) Winter
-3 -2.7-2.4-2.1-1.8-1.5-1.2-0.9-0.6-0.30 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3
-80 -70 -60 -50 -40 -30 -20
-55
-50
-45
-40
-35
-30
-25
-20
-15
AAO (-) Spring
-3 -2.7-2.4-2.1-1.8-1.5-1.2-0.9-0.6-0.30 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3
-80 -70 -60 -50 -40 -30 -20
-55
-50
-45
-40
-35
-30
-25
-20
-15
AAO (+) Summer
-3 -2.7-2.4-2.1-1.8-1.5-1.2-0.9-0.6-0.30 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3
-80 -70 -60 -50 -40 -30 -20
-55
-50
-45
-40
-35
-30
-25
-20
-15
AAO (+) Autumn
-3 -2.7-2.4-2.1-1.8-1.5-1.2-0.9-0.6-0.30 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3
-80 -70 -60 -50 -40 -30 -20
-55
-50
-45
-40
-35
-30
-25
-20
-15
AAO (+) Winter
-3 -2.7-2.4-2.1-1.8-1.5-1.2-0.9-0.6-0.30 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3
-80 -70 -60 -50 -40 -30 -20
-55
-50
-45
-40
-35
-30
-25
-20
-15
AAO (+) Spring
- AAO - AAO - AAO- AAO
+AAO+AAO+AAO+AAO
(Reboita, Ambrizzi & Rocha 2007)
REOF Precipitation anomalies DJF 1950 to 20014th rotated mode - 6.6% of the total variance
EN
EN EN
EN
LN LN
LNLN
LN LN LN
EN
EN
N N
N
1951/52, 1956/57, 1959/60, 1964/65, 1967/68, 1978/79, 1984/85, 1986/87, 1988/89
1957/58, 1970/71, 1972/73, 1976/77, 1980/81, 1983/84, 1997/98
ZCAS -
7 events
ZCAS +
9 events
Drumond (2005)
SACZ+ SACZ -
Composite of DJF precipitation anomalies (mm.day-1)
Composite of DJF SST anomalies (ºC)
Composite of DJF 200hPa anomalous zonally asymmetric component of stream function (x 106m2/s) anomaliesDrumond (2005)
Low Frequency SST Variability modes related to the South American Monsoon System
DJF SST Modes related to the SACZ -
Drumond (2005)
DJF SST Modes related to the SACZ +
Pm
Tm
Em
Em = Equatorial Mass
Tm = Tropical Mass
Pm = Polar Mass
SEASONAL CYCLONE TRACKS
SUMMER AUTUMN
WINTERSPRING
(Beu and Ambrizzi 2006)
CYCLONES, ANTICYCLONES AND COLD AIR MASS
(Pezza and Ambrizzi 2005)
Day -3
Day -2
Day -1
Day 0
Generalized Frost (+σ)
Phase coincidence
(Muller et al 2005)
The anomalous 250hPa meridional wind component
(ms-1)
(Muller and Ambrizzi 2007)
The anomalous 250hPa meridional wind component (ms-1) 14th day of integration
The importance of the phases coincidence:
Keeping the polar air advection over a large region Provoking an intense decrease in the surface temperature
Basic State +σ
Wind at 250 hPa
BETA
Ks
GF +σ GF -σ
(Muller and Ambrizzi 2007)
SST<0
H L
SST<0SST<0
H L
(Muller e Ambrizzi 2006)
SCHEMATIC CONCEPT OF POSSIBLE SCHEMATIC CONCEPT OF POSSIBLE GENERALIZED FROST MECHANISMGENERALIZED FROST MECHANISM
GRUPO DE ESTUDOS CLIMÁTICOS
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