ANALYSIS OF EXTREME EVENTS VARIABILITY AND QUANTIFICATION OF

ANALYSIS OF EXTREME EVENTS VARIABILITY AND QUANTIFICATION OF MODEL UNCERTAINTIES Matilde Rusticucci, Olga Penalba Assistant Researchers: Mariana Barrucand, María Laura Bettolli Post-Doc: Bárbara Tencer, Madeleine Renom, Ph. D Students: Federico Robledo, Natalia Zazulie, Juan Rivera, Vanesa Pántano, Gustavo Almeira Laboratorio de Extremos Climáticos de Sudamérica Departamento de Ciencias de la Atmósfera y los Océanos- FCEN- Universidad de Buenos Aires / CONICET

October - March Extreme Temperatures ETCCDI Linear trend 1959 -2003 Cold Days MAX TEMP 10 th perc. Warm Days MAX TEMP 90 th perc. April-September Cold Days MAX TEMP 10 th perc. Warm Days MAX TEMP 90 th perc. Barrucand, Ph. D thesis

TEMPORAL VARIABILITY Tucumán November WET CONDITION December Monthly accumulated extreme rainfall greater than 75 th daily percentile. DRY CONDITION Annual Amount of Dry days Index Penalba, Bettolli; Robledo; Rivera; . Pántano Salta

Observed Changes in Return Values of Annual Temperature Extremes over Argentina Matilde Rusticucci And Bárbara Tencer Journal Of Climate Volume 21 HTx 40ºC LTx 6ºC HTn 25ºC LTn -5ºC Spatial distribution of return periods - 1956 -2003

GEV observed (black - - -) ERA -40 (solid black ) and GCMs. GEV 1981 -1999( - - -) 2010 -2040(solid )

Covariability between daily intensity of extreme rainfall (DIER) and Sea Surface Temperature Second mode 17% (Singular Value Descomposition) Austral Spring SON DIER correlation of the second mode

De-trended annual time-series (blue) and smoothed with a 10 -year running mean (red) of indices

Interdecadal changes in the relationship between extreme temperature events in Uruguay and the general atmospheric circulation. Madeleine Renom , Matilde Rusticucci , Marcelo Barreiro accepted in Climate Dynamics, 2011) Summer 1946 -1975 1976 -2005 Cold nights Warm nights 1946 -1975 1976 -2005 Cold days Warm days

Regressions maps of TN 10 onto, for summer. SLPa the negative phase of the SAM is associated with more frequent cold nights 1949 -1975 No relationship at all with the SAM. vector wind at 925 h. Pa. vector wind at 200 h. Pa 1976 -2003

Frost Days Models overestimate 1961 -2000 mean Figure 2: The same as Figure 1 except for FD: number of days where the minimum temperature was below

R 10 1961 -2000 mean Models overestimate Models underestimate Figure 3: The same as Figure 1 except for R 10: number of days where the precipitation was over 10 mm/day.

PART 2: HISTORICAL TRENDS TN 90 R 10 CDD

% TN 90 1965 1970 1975 1980 1985 1990 1995 2000 Days R 10 1965 1970 1975 1980 1985 1990 Days CDD 1995 2000

% TN 90 1965 1970 1975 1980 1985 1990 1995 2000 Days R 10 1965 1970 1975 1980 1985 1990 1995 Days CDD 1960 1965 1970 1975 1980 1985 1990 1995 2000

Daily circulation patterns in Southern South America Observed Circulation Types (CT) and percentage of days corresponding to each group during austral summer. DJF CT 2 26. 8% highest contribution to heavy rainy days in the Pampas (blue square) CT 4 19% highest contribution to dry days in the Pampas (blue square) Daily mean sea level pressure (SLP) fields. 1979 -1999.

Evaluation of the capacity of a set of GCMs to reproduce these atmospheric structures CT 2 26. 8% CT 4 19%

Projected changes at different time horizons of 21 th century Frequency (%) of CTs for summer for NCEP (red diamond), GCMs (circles) and ensemble of GCMs (blue diamond). 20 th Century 2046 -2065 2081 -2099 Anomalies of the frequencies of the CTs with respect to 20 th Century in two horizons.

Future plans: Evaluate the relevance of the decadal Analyze the physical Assess the ability extreme events variability in the occurrence of extreme events processes involved in the occurrence of extreme events of global models to reproduce the observed decadal variability of Contribute to greater understanding and prediction of future climate extremes. Estimate the frequency of extreme events in the coming Matilde Rusticucci, Olga Penalba Assistant Researchers: Mariana Barrucand, María Laura Bettolli Post-Doc: Bárbara Tencer, Madeleine Renom, Ph. D Students: Federico Robledo, Natalia Zazulie, Juan Rivera, Vanesa Pántano, Gustavo Almeira years Laboratorio de Extremos Climáticos de Sudamérica Departamento de Ciencias de la Atmósfera y los Océanos- FCEN- Universidad de Buenos Aires / CONICET