extremes events and observed regional (south america) trends: a preliminary review luis j. mata 1...
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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
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]
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
Location (Continent)
Duration(Days)
Affected Region (sq km)
Damage(USD perSq. km)
C. Europe(Europe)
18(August)
252.300 79.270
S. Russia(Asia)
12(June)
224.600 1.945
W. Venezuela(South America)
11(July)
224.900 13,34
NW China(Asia)
10(June)
252.000 1.587
Location (Continent)
Duration(Days)
Affected Region (sq km)
Damage(USD perSq. km)
C. Europe(Europe)
18(August)
252.300 79.270
S. Russia(Asia)
12(June)
224.600 1.945
W. Venezuela(South America)
11(July)
224.900 13,34
NW China(Asia)
10(June)
252.000 1.587
Location (Continent) Location (Continent)
Duration(Days) Duration(Days)
Affected Region (sq km)
Affected Region (sq km)
Damage(USD perSq. km)
Damage(USD perSq. km)
C. Europe(Europe) C. Europe(Europe)
18(August)18(August)
252.300252.300 79.27079.270
S. Russia(Asia)S. Russia(Asia)
12(June)12(June)
224.600224.600 1.9451.945
W. Venezuela(South America)
W. Venezuela(South America)
11(July)11(July)
224.900224.900 13,3413,34
NW China(Asia) NW China(Asia)
10(June)10(June)
252.000252.000 1.5871.587
Source: Darmouth Flood ObservatoryPhoto: C.Stache/AP
DRESDEN
Figure 5. Some global examples of floods occurred during the summer of 2002
Location Duration (days) Affected Region(sq. km) x 103
Damages (USD per sq. km)
Argentina & Brazil
21 424 85.714
Brazil Central 2 0,780 8.974
Brazil West 2 2,2 ni
Chile 12 166,9 190
Ecuador 54 52,93 ni
Peru 11 333,2 ni
Trinidad 15 0, 880 3.750
Uruguay 30 187,5 ni
Venezuela 11 224,9 13,34
Some floods in South America during 2002
Data source: Dartmouth Flood Observatory LJM, 2003
Daily and Cumulative Rainfall
0
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400
600
800
1000
1200
1400
0 2 4 6 8 10 12 14 16 18
Time (days)
Pre
cip
itat
ion
in m
m
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,2002Source: MARN,2000
cumulative
daily
Observations
Mean T0
An increase in mean and variance imply anonlinear increase in the probability of extremes
± 1 SD
LJM,2002
Threshold 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 (1904-1960 and 1961-1997)
Source: Valdés, 2002 personal communication
Mean T0Mean T0Mean T0
LJM,2002
Threshold ThresholdThresholdThreshold ThresholdThreshold
New MeanNew MeanNew Mean
Probability of high extremes
Probability of low extremes
Probability of high extremesProbability of high extremesProbability of high extremes
Probability of low extremesProbability of low extremes
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.
500 1000 1500 2000 2500
0.0000
0.0004
0.0008
0.0012
Figure 5. Annual precipitation PDF at Corrientes, Argentina
Annual rainfall in mm
Density
Mean 1902-1944= 1181.88 mmMean 1945-1999 =1831.00 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)International Symposium on Climate Change (ISCC)
31 March to 3 April 2003, Beijing; China
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