Centro Internacional para la Investigación del Fenómeno de El Niño

I FORO DE PERSPECTIVAS CLIMÁTICAS PARA SUDAMÉRICAGuayaquil - Ecuador, 01 al 04 de Octubre 2012

Seminario - Taller Clima de Sud América

Cambio Climático en SA: Observaciones y Proyecciones

Relator: Dr. René D. Garreaudwww.dgf.uchile.cl/rene

Departamento de GeofísicaUniversidad de Chile

Is the regional cooling of theHumboldt EBUS already taking place?

Over the Pacifc SST trend looks very similar to the PDV patter

2006-1979

Falvey & Garreaud 2007

Is th

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al c

oolin

g of

the

Hum

bold

t EBU

S al

read

y ta

king

pla

ce?

offshore

coast

inland

WestAndes

East Andes

Falvey & Garreaud 2007

Trends in°C/décade (1984 – 2010), from Trends in°C/décade (1984 – 2010), from Reynolds data base (1/4° resolution) Reynolds data base (1/4° resolution) (Gutiérrez et al., RPGA, subm.)(Gutiérrez et al., RPGA, subm.)

Callao

PiscoSan Juan

Ilo

13

14

15

16

17

18

19

pee

rs S

ST

(ºC

)

15

16

17

18

19

20

1950 1960 1970 1980 1990 2000 2010

14

15

16

17

18

19

20

18

19

20

21

22

23

24

Callao (12°S)y =57.8 - 0.021 y -1

p<0.05

Pisco (13.8°S)

San Juan (15.5°S)y = 86.0 - 0.036y-1

p<0.1

Ilo (17°S)y = 47.0 - 0.016 y-1

p<0.05

y = 102.3 - 0.041y-1

p<0.001

Gutiérrez, Bouloubassi, et al., GRL, to be submitted

Is th

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bold

t EBU

S al

read

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pla

ce?

Temperature trends 1979-2006

Falvey & Garreaud 2007

How are the models doing?Not good but no so bad..

T/toff Central Chile

T/tcentral Andes

Multimodel mean Regional warming 1970-2000 (SST*). Also shown in contours SLP* trend

Global mean: +0.2º/dec

TENDENCIA DE LA PRECIPITACION ANUAL - 1950-2000

-200

-150

-100

-50

0

50

100

1503

0

32

33

34

35

37

38

39

40

42

45

53

Latitud Sur

mm

/10

añ

os

Ref.: Quintana, 2004

• Semiarid climate• MAP 30-500 mm• (IA)/MAP 0.3 – 0.5• Strong ENSO Impact• No significant trend

Precipitation Changes….warming, drying south

• Rainy climate• MAP 1000-3000 mm• (IA)/MAP 0.1• Weak ENSO Impact• Significant drying trend

Central Chile (30-35ºS)

Southern Chile (38º-41ºS)

Year

Norm

aliz

ed

rain

fall

Norm

aliz

ed

rain

fall

Evolu

ción d

e las

Pre

cip

itaci

on

es

Tendencias observadas de precipitación: ¿?

Retro-alimentación del sistema climáticocambian la respuesta al incremento del CO2

Ruddiman: Earth’s Climate, Chapter 4

Parte “facil”Calculo radiativo…

Future Climate ScenariosGHG (CO2,…) emissions projections + GCMs

20+ GCMsCMIP3/IPCC AR4

© IPCC 2007: WG1-AR4 (2007)

© IPCC 2007: WG1-AR4 (2007)

© IPCC 2007: WG1-AR4 (2007)

Zonal mean distribution of temperature change (2xC02-Ctr)

© IPCC 2007: WG1-AR4 (2007)

Multimodel average SLP difference betweenA2 (2070-2100) and BL (1970-2000)

Strengthening of the poleward flank of subtropical anticyclones and poleward shift of the midlatitude storm track is very consistent among GCMs

Annual mean

Garreaud & Falvey 2007

Multimodel average SLP and sfc wind difference betweenA2 (2070-2100) and BL (1970-2000)

Over open ocean v in geostrophic balance with SLP.Near the coast v more controlled by along-coast SLP

Annual mean

Garreaud & Falvey 2007

2 month extended upwelling season(earlier onset, later demise)

Stronger southerlies

PRECIS Results

Garreaud & Falvey 2007

Las Cruces

Lavapie

QuikScat data (2000-2006)PRECIS BL (1961-1990)PRECIS A2 (2071-2100)

Frequency of surface meridional wind speed at 33°S 74°W

PRECIS Results

Garreaud & Falvey 2007

More frequent /extended episodes ofstrong southerlies

Less downwellingfavourable wind

PRECIS Results

-1° 0° 1° 2° 3° 4° 5° C

Differences A2(2100-2070) – BL(1960-1990)Obtained with a regional climate model (PRECIS) forced by HadCM3 / A2

-50 0 +50 mm/mes

Temperatura Superficial (SAT) Precipitación (P)

PRECIS-DGF-UCH

Urrutia and Vuille 2009

Diferencia T2m (2100-2070) – (1960-1990)Obtained with a regional climate model (PRECIS) forced by Echam4 / A2

B2-LB A2-LB

Diferencia Pp A2(2100-2070) – BL(1960-1990)Obtained with a regional climate model (PRECIS) forced by Echam4 / A2

dP (mm/año) dP/Pbl (%)

Urrutia and Vuille 2009

Multimodel mean diff. A2-BLin 200 hPa wind, summer

Multimodel mean diff. A2-BLin zonal wind along 70°W

summer

Cambios de Circulación A2- BL

Minvielle and Garreaud 2010

Cambios de Precipitación esperables por cambio de viento

Minvielle and Garreaud 2010

dP (mm) dP/Pbl (%)