Extremes events and observed regional (South America) trends: A preliminary review Luis J. Mata 1 M.Rusticucci 2, S.Solman 3 J. B. Valdés 4 1 ZEF, University of Bonn, Germany, 2 Departamento de Ciencias de la Atmósfera y los Océanos, Universidad de Buenos Aires, Buenos Aires, Argentina, 3 CIMA (Centro de Investigaciones del Mar y la Atmosfera) and Departamento de Ciencias de la Atmósfera y los Océanos, Universidad de Buenos Aires, Buenos Aires, Argentina, 4 Dept. of Civil Engineering and SAHRA (Sustainability for Semi-Arid Hydrology and Riparian Areas) Center, The University of Arizona, Tucson, Arizona, Contributing author: Olga Penalba, Argentina Zentrum für Entwicklungsforschung [ZEF] ISCC Beijing March 2003

Outline and Objectives In addition to changes in the mean values it is very important to examine trends in extreme events in the perspective of more generally quantities such as annual temperature and precipitation. It should be expected that a linear change in the mean and a change in the variability would generate a non-linear increase in the probability of the extremes (validation) Theory and Observations

The planet averaged an even 14.0 C between The average temperature in 2001 was C the second warmest year on record Global average mean temperature has increased by 0.6± 0.2 ° C since the late 19 th century

Temperature and Precipitation - The increased in temperature is associated with an stronger warming in daily minimum temperatures than maximum (Easterling et al., 1997) - Global precipitation has also increased since the late 19 th century (IPCC, 2001). - Given these increases, it is expected that there would also be increases in extreme events (Mearns et al., 1984)

Figure 3 Trends on extreme temperatures for the period in the province of Mendoza, Argentina. Temperature extremes Source: Matilde Rusticucci, 2002, personal communication Numbers of days below freezing have decreased Positive tendency for the numbers of days above 30 °C

Heavy Precipitation and Floods An increase in heavy precipitationevents should be a primary sign of the climate change that goes together with an increase in greenhouse gases in the atmosphere. An increse concentration of ggh´s in the atmosphere increase infrared radiation, and this global heating at the surface not only act to increase temperatures but also increases evaporation with enhances the atmospheric moisture content (K. Trenberth, 1999) Heavy precipitation is necesary condition for floods

Figure 5. Some global examples of floods occurred during the summer of 2002

LocationDuration (days)Affected Region (sq. km) x 10 3 Damages (USD per sq. km) Argentina & Brazil Brazil Central20, Brazil West22,2ni Chile12166,9190 Ecuador5452,93ni Peru11333,2ni Trinidad150, Uruguay30187,5ni Venezuela11224,913,34 Some floods in South America during 2002 Data source: Dartmouth Flood Observatory LJM, 2003

Figure 4. Rainfall occurred in Venezuela on December 1999 caused over 30,000 deaths and great economic losses. Heavy Precipitation and floods Annual maxima 951mm in 1954 LJM,2002 Source: MARN,2000 cumulative daily

Observations

Mean T 0 An increase in mean and variance imply a nonlinear increase in the probability of extremes ± 1 SD LJM,2002 Threshold New Mean Probability of high extremes Probability of low extremes Theory

Figure 3. Extreme value distributions of maximum flows on Paraná river at Corrientes ( and ) Source: Valdés, 2002 personal communication

Figure 2. A linear increase in the mean and variability imply a non-linear probability of extremes Source: Mata, Workshop of extreme events, Beijing 2002.

Figure 5. Annual precipitation PDF at Corrientes, Argentina Annual rainfall in mm D ensity Mean = mm Mean = mm Source: Olga Penalba, personal comunication 2002 LJM,2003

Trends on annual and seasonal (DJF and JJA) rainfall in Corrientes, Argentina

International Symposium on Climate Change (ISCC) 31 March to 3 April 2003, Beijing; China Thanks ! Xie xie

Figure 1: Combined annual land surface air and sea surface temperature anomalies (°C) 1861 to 2000 relative to 1961 to Two standard error uncertainties are shown as bars on the annual numbers. Global average mean temperature has increased by 0.6± 0.2 ° C since the last century Source: IPCC 2001

Extremes events and observed regional (South America) trends: A preliminary review Luis J. Mata 1 M.Rusticucci 2, S.Solman 3 J. B. Valdés 4 1 Center for Develompment Research, University of Bonn, Germany, 2 Departamento de Ciencias de la Atmósfera y los Océanos, Universidad de Buenos Aires, Buenos Aires, Argentina, 3 CIMA (Centro de Investigaciones del Mar y la Atmosfera) and Departamento de Ciencias de la Atmósfera y los Océanos, Universidad de Buenos Aires, Buenos Aires, Argentina, 4 Dept. of Civil Engineering and SAHRA (Sustainability for Semi-Arid Hydrology and Riparian Areas) Center, The University of Arizona, Tucson, Arizona, ZEF

LocationDuration (days)Affected Region (sq. km) x 10 3 Damages (USD per sq. km) Argentina & Brazil Brazil Central20, Brazil West22,2ni Chile12166,9190 Ecuador5452,93ni Peru11333,2ni Trinidad150, Uruguay30187,5ni Venezuela11224,913,34 Some floods in South America during 2002 Data source: Dartmouth Flood Observatory LJM, 2003