Centro Internacional para la Investigación del Fenómeno de El Niño I FORO DE PERSPECTIVAS CLIMÁTICAS PARA SUDAMÉRICA Guayaquil - Ecuador, 01 al 04 de Octubre 2012 Seminario - Taller Clima de Sud América Cambio Climático en SA: Observaciones y Proyecciones Relator: Dr. René D. Garreaud Departamento de Geofísica Universidad de Chile

Is the regional cooling of the Humboldt EBUS already taking place? Over the Pacifc SST trend looks very similar to the PDV patter Falvey & Garreaud 2007

Is the regional cooling of the Humboldt EBUS already taking place? offshore coast inland West Andes East Andes Falvey & Garreaud 2007

Trends in°C/décade (1984 – 2010), from Reynolds data base (1/4° resolution) (Gutiérrez et al., RPGA, subm.) Callao Pisco San Juan Ilo Gutiérrez, Bouloubassi, et al., GRL, to be submitted

Is the regional cooling of the Humboldt EBUS already taking place? Temperature trends Falvey & Garreaud 2007

How are the models doing? Not good but no so bad..  T/  t off Central Chile  T/  t central Andes

Multimodel mean Regional warming (SST*). Also shown in contours SLP* trend Global mean: +0.2º/dec

Ref.: Quintana, 2004 Semiarid climate MAP  mm  (IA)/MAP  0.3 – 0.5 Strong ENSO Impact No significant trend Precipitation Changes….warming, drying south Rainy climate MAP  mm  (IA)/MAP  0.1 Weak ENSO Impact Significant drying trend

Central Chile (30-35ºS) Southern Chile (38º-41ºS) Year Normalized rainfall Evolución de las Precipitaciones

Tendencias observadas de precipitación: ¿?

Retro-alimentación del sistema climático cambian la respuesta al incremento del CO 2 Ruddiman: Earth’s Climate, Chapter 4 Parte “facil” Calculo radiativo…

Future Climate Scenarios GHG (CO2,…) emissions projections + GCMs 20+ GCMs CMIP3/IPCC AR4

© IPCC 2007: WG1-AR4 (2007)

Zonal mean distribution of temperature change (2xC02-Ctr) © IPCC 2007: WG1-AR4 (2007)

Multimodel average SLP difference between A2 ( ) and BL ( ) 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 ( ) and BL ( ) 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 ( ) PRECIS BL ( ) PRECIS A2 ( ) Frequency of surface meridional wind speed at 33°S 74°W PRECIS Results Garreaud & Falvey 2007 More frequent / extended episodes of strong southerlies Less downwelling favourable wind

PRECIS Results

-1° 0° 1° 2° 3° 4° 5° C Differences A2( ) – BL( ) Obtained with a regional climate model (PRECIS) forced by HadCM3 / A mm/mes Temperatura Superficial (SAT) Precipitación (P) PRECIS-DGF-UCH

Urrutia and Vuille 2009 Diferencia T 2m ( ) – ( ) Obtained with a regional climate model (PRECIS) forced by Echam4 / A2 B2-LBA2-LB

Diferencia Pp A2( ) – BL( ) Obtained with a regional climate model (PRECIS) forced by Echam4 / A2 dP (mm/año) dP/Pbl (%) Urrutia and Vuille 2009

Multimodel mean diff. A2-BL in 200 hPa wind, summer Multimodel mean diff. A2-BL in 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 (%)