PRECIPITATION ANOMALIES OVER SOUTH AMERICA IN THE

SUMMER SEASONIN SCENARIOS OF CLIMATE CHANGE

Iracema Fonseca de Albuquerque Cavalcanti

CENTRO DE PREVISÃO DE TEMPO E ESTUDOS CLIMÁTICOS

INSTITUTO NACIONAL DE PESQUISAS ESPACIAIS

COLD AIR OUTBREAKS OVER SOUTHEASTERN SOUTH AMERICA IN THE

WINTER SEASONIN SCENARIOS OF CLIMATE CHANGE

Gabriela Müller Kelen Andrade Iracema FA Cavalcanti

ANOMALOUS PRECIPITATION OVER SOUTH AMERICA

• NATURAL CLIMATE VARIABILITY

• ENSO CONDITIONS (EL NINO / LA NINA)

• TELECONNECTIONS

• INTRASEASONAL OSCILLATION

• BEHAVIOUR OF SYNOPTIC SYSTEMS

• BLOCKING SITUATIONS

• ETC

DROUGHT IN 2005

DROUGHT IN 2000/2001

DROUGHT IN 1997/1998

THE QUESTION IS:WILL THE ANOMALIES CHANGE

IN SCENARIOS OF CLIMATE CHANGE OVER SOUTH AMERICA?

HOW THE INTENSITY OF NATURAL VARIABILITY CAN CHANGE IN THE

FUTURE?

MODELS

CPTEC/COLA AGCM

DJF PRECIPITATIONCMAP/CAMS

Extreme wet years composite Extreme dry years composite

SOUTHEASTERN BRAZIL (50W-40W; 15-25S)

Extreme wet years composite Extreme dry years composite

IPCC-4 MODEL SIMULATIONS

20 CENTURYSRES A2

PRE-INDUSTRIAL

1% CO2 INCREASE

MODELS

HADLEY HADCM3

GFDL

HADGEN

MRI

ECHAM

CANADIAN

Increase from CO2= 286.05 ppm at 1% /year rate to doubling, then constant to year 280. Other gases cte from 1860

1% CO2 EXPERIMENT

20TH CENTURY EXPERIMENT

Considers all anthropogenic forcings during the period of 1860 to 2000 (140 years)

EXPERIMENTS

SRES A2High degree of global economic development (means high concentration of greenhouse gases)

(2000-2100)

Forcings agents representative of 1860 conditions constant. Include all greenhouses gases (280 years)

PRE-INDUSTRIAL EXPERIMENT

PERIODS OF ANALYSIS

• LAST 51 YEARS FROM EACH SIMULATION

• DJF (S.H. SUMMER)

• 20 CENTURY : 1949-1999

• SRES A2: 2048- 2098 OR 2049-2099

20 CENTURY

DJF 1979/1980 TO 1999/2000

GFDL MRI HADCM3

OBSERVED

PRECIPITATION

MODELS SIMULATIONS

HADGEN ECHAM

OBSERVED

PRECIPITATION

CANADIAN

MODELS SIMULATIONS

Difference between two periods in the pre-industrial experiment (year 71 to 280)- (year 11 to 70).

The changes are very small, consistent with the absence of anthropogenic forcings.

PRE-INDUSTRIAL EXPERIMENT GFDL

The impact on precipitation is seen in the region of

South Atlantic Convergence Zone

and Southeastern South America considering the two experiments.

DIFFERENCES BETWEEN 1%CO2 AND PRE-INDUSTRIAL EXPERIMENT GFDL

DIFFERENCES BETWEEN 1%CO2 AND 20th century EXPERIMENTS GFDL

ANNUAL GFDL

GFDL (USA) DIFFERENCES (FUTURE -20TH CENTURY)

DJF1%CO2 SRES A2

HADCM3 (UK)

DIFFERENCES (FUTURE -20TH CENTURY)

1%CO2 SRES A2DJF

GFDL20 CENTURY LAST PERIOD 1% CO2 INCREASE

250 hPa

850 hPa

Difference between SRES A2 and 20th century wind flow

HADLEY.

EXTREME MONTHLY PRECIPITATION ANOMALIES

DJF

• Average of precipitation anomalies over several areas of South America

• 5 extreme years (+ and -)

• 20th century and SRES A2

• Hadley and GFDL

WAmazonia

E

Amazonia

N La Plata

S La Plata

AREAS

AREAS

SE

NE

GFDL

AMAZONIA

WESTERN SECTOR

20th century A2 ANOMALIES RELATED TO THE CLIMATOLOGY OF 20TH CENTURY

PRECIPITATION ANOMALIES

EASTERN SECTOR

GFDL

PRECIPITATION ANOMALIES (AMAZONIA) GFDL

LA PLATA NORTHERN SECTOR

LA PLATA SOUTHERN SECTOR

GFDL

PRECIPITATION ANOMALIES LA PLATA SOUTHERN SECTORGFDL

NORTHEAST BRAZILGFDL

PRECIPITATION ANOMALIES NORTHEAST BRAZIL

SOUTHEAST (50W-40W; 15S-25S)

PRECIPITATION ANOMALIES SOUTHEAST BRAZIL

HADLEY

HADLEY

AMAZONIA WESTERN SECTOR

EASTERN SECTOR

20th century A2 ANOMALIES

NORTHEAST BRAZIL

LA PLATA NORTHERN SECTOR

LA PLATA SOUTHERN SECTOR

SOUTHEAST Brazil

HADLEY

20th century

SRES A2

PRECIPITATION ANOMALY CORRELATIONS AREA 15S-25S; 40W-50W (SOUTHEAST) GFDL

GFDL

HADCM3

HADCM3

EXTREME PRECIPITATION ANOMALIES SOUTHEAST (50W-40W; 15S-25S) 20th century

GFDL HADCM3

GFDL HADCM3

NEGATIVE

ANOMALIES

POSITIVE ANOMALIES

EXTREME PRECIPITATION ANOMALIES SOUTHEAST

(50W-40W; 15S-25S) SRES A2

GFDL HADCM3

COLD AIR OUTBREAKS OVER SOUTH AMERICA

• CNPq colaboration project Argentina, Uruguay, Brazil.

• Objective: Identify frequency and intensity of extreme cold air outbreaks in the present climate and in the future.

• Will the global warming affect the frequency and intensity of the cold air outbreaks?

TEMPERATURE CHANGES (annual)

GFDL

1% CO2 increase

– preindustrial

1% CO2 increase – 20 century

Frequency of cold air over Brazil, Argentina and Uruguay

• Daily data at (925hPa), 850 hPa

• SLP, meridional wind and Temperature

• Average over areas

• 52W-57W; 23S-28S (Brazil)

• 52W-57W; 28S-33S (Uruguay)

• 65-60W; 33-38S (Argentina)

criterium

• Temperature interval (0-2.5c , < 0c)

• Reduction of temperature (5-8c; 8-10c; >10c)

• Increase of SLP and southerly flow at 850hPa

ARGENTINA STATIONS

0

2

4

6

8

10

12

14

16

18

1964 1966 1968 1970 1972 1974 1976 1978 1980 1982 1984 1986 1988 1990

frec NCEP

frec OBS

OBS: TEMP. AT 2m

Reanalysis: 850hPa

TEMP. 850 hPa 0-2.50 c

1960-1990

FUTURE

65-60W

33-38S

ARGENTINA - Categoria 0 - 2,5

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NCEPGFDLHADDiário

ARGENTINA - Categoria 0 - 2,5

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HADDiárioGFDLF

Argentina

ARGENTINA - Categoria < 0

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NCEPGFDLHADDiário

TEMP. 850 hPa < 0 c

1960-1990

65-60W33-38S

FUTURE

ARGENTINA - Categoria < 0

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HADDiário

GFDLF

Argentina

FUTURE

1960-1990

TEMP. 850 hPa

0-2.50 c

52W-57W

23S-28S

BRASIL - Categoria 0 - 2,5

0

1

2

3

4

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8

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NCEPGFDLHADDiário

BRASIL - Categoria 0 - 2,5

0

1

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HADDiário

GFDLF

Brazil

FUTURE

1960-1990

Temp. 850 hPa

<00 c

52W-57W 23S-28S

BRASIL - Categoria < 0

0

1

2

3

4

5

6

7

8

9

10

1960

1961

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NCEPGFDLHADDiário

BRASIL - Categoria 0 - 2,5

0

1

2

3

4

5

6

7

8

9

10

20

80

20

81

20

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HADDiário

GFDLF

Brazil

Next criterium

• Calculate anomalies and analyze the extremes in each area.

• Use SLP and meridional wind to get cases associated with frontal systems.

CONCLUSION

COMMON FEATURES IN THE MODELS

• INCREASE OF PRECIPITATION OVER NORTHWESTERN AND SOUTH/ SOUTHEASTERN SOUTH AMERICA.

• REDUCTION OF PRECIPITATION OVER SOUTHWESTERN SOUTH AMERICA.

• THERE IS AGREEMENT IN CHARACTERISTICS ASSOCIATED WITH EL NINO INFLUENCE IN SOME REGIONS

REGIONS WITH DIFERENT RESULTS IN DIFERENT MODELS

• SUGGEST UNCERTAINTY IN CHARACTERIZING THE FUTURE CLIMATE IN THESE REGIONS.

• AND • THE NEED TO ANALYSE RESULTS OF

OTHER MODELS.

• MULTI-MODEL ENSEMBLE

• Extreme monthly anomalous precipitation intensifies in some regions

• Dipole patterns are reproduced in 20th century and future climate scenario

• Extremes are connected in some areas

Frequency of cold air cases

• Number of cold air outbreaks are better simulated by Hadley model (20th century) in two areas of South America.

• Frequency reduces in SRES A2 scenario

• (still analysing the intensity)

WORK IN PROGRESS

• IDENTIFICATION OF MECHANISMS ASSOCIATED WITH THE CHANGES.

• ANALYSIS OF MODEL PATTERNS ASSOCIATED WITH THE COLD AIR OUTBREAKS

• ANALYSIS OF DAILY PRECIPITATION AND TEMPERATURE DATA TO IDENTIFY EXTREMES

• ANALYSIS OF OTHER IPCC MODELS

ACKNOWLEDGEMENTS

To CNPq for research supportTo CNPq/Prosul project

To international modeling groups for providing their data for analysis, the Program for Climate Model Diagnosis and Intercomparison (PCMDI) for collecting and archiving the model data,   the JSC/CLIVAR Working Group on Coupled Modelling (WGCM) and their   Coupled Model Intercomparison Project (CMIP) and Climate Simulation Panel for organizing the model data analysis activity, and the IPCC WG1 TSU for technical support. The IPCC Data Archive at Lawrence Livermore National Laboratory is supported by the Office of Science, U.S. Department of Energy.