Extremes events and observed regional Extremes events and observed regional (South America) trends: A preliminary (South America) trends: A preliminary review review Luis J. Mata 1 M.Rusticucci 2 , S.Solman 3 J. B. Valdés 4 1 ZEF, University of Bonn , Germany, [email protected]2 Departamento de Ciencias de la Atmósfera y los Océanos, Universidad de Buenos Aires , Buenos Aires, Argentina, [email protected]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, [email protected]4 Dept. of Civil Engineering and SAHRA (Sustainability for Semi-Arid Hydrology and Riparian Areas) Center, The University of Arizona , Tucson, Arizona, [email protected]Zentrum für Entwicklungsforschung [ZEF] ISCC Beijing March 2003
16
Embed
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.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Extremes events and observed regional Extremes events and observed regional (South America) trends: A preliminary review(South America) trends: A preliminary review
Luis J. Mata 1 M.Rusticucci 2, S.Solman 3 J. B. Valdés 4
2 Departamento de Ciencias de la Atmósfera y los Océanos, Universidad de Buenos Aires, Buenos Aires, Argentina, [email protected]
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, [email protected]
4 Dept. of Civil Engineering and SAHRA (Sustainability for Semi-Arid Hydrology and Riparian Areas) Center, The University of Arizona, Tucson, Arizona, [email protected]
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 theperspective of more generally quantities such as annual temperature and precipitation.
It should be expected that a linear change in the meanand a change in the variability would generate a non-linearincrease in the probability of the extremes
(validation) Theory and Observations
The planet averaged an even 14.0 C between 1961-90. The average temperature in 2001 was 14.43 C the second warmest year on record
Global average mean temperature has increased by 0.6± 0.2 ° C since the late 19th 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 19th century (IPCC, 2001).
- Given these increases, it is expected that there would also be increases in extreme events (Mearns et al., 1984)
0
20
40
60
80
100
120
140
160
1960 1965 1970 1975 1980 1985 1990 1995 2000
Years
Nu
mb
er o
f d
ays
per
yea
r
Tmin < 0 C Tmax > 30 Linear (Tmax > 30) Linear (Tmin < 0 C)
Figure 3 Trends on extreme temperatures for the period 1960-2000 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 togetherwith an increase in greenhouse gases in the atmosphere.
An increse concentration of ggh´s in the atmosphere increase infrared radiation, and this global heatingat the surface not only act to increase temperatures but also increases evaporation with enhances theatmospheric moisture content (K. Trenberth, 1999)
Heavy precipitation is necesary condition for floods