observed changes in climatic variables relevant for agricultural production during 1930-2000 in the...

Observed changes in climatic variables relevant for

agricultural production during 1930-2000 in the Pampas region of Argentina, Brazil and Uruguay

(AIACC Project No. LA27)

Walter E. Baethgen (IRI Columbia University-INIA, Uruguay)

Agustin Gimenez (INIA, Uruguay)

Graciela Magrin (INTA-Argentina)

Maria I. Travasso (INTA-Argentina)

Gilberto Cunha (EMBRAPA, Brasil)

Mauricio Fernandes (EMBRAPA, Brasil)

Objectives

Explore changes in the last 70-100 years observed in climate variables that are relevant for agricultural production

Establish the basis for one of the methods used inour project to create climate change scenarios:project changes observed in the last 70-100 yearsto the next 10-20 years using a weather generator(G. Magrin’s presentation)

MethodsLinear regression of mean trimester rainfall and temperatures for the entire available period (1930 – 2000)Stat significance using parametric and non-parametric (Kendall) tests

Plot slopes using a contouring and surface mapping program (Surfer)to study spatial distribution of changes

Expected Result

Annual mean changes of the trimester means for Rainfall, T Max, T Min in the entire period (1930 - 2000)

Remaining Question:

Were changes uniform throughout the entire period?Time

Methods (2)

Compare rainfall and temperature means for different periods:

10-year periods: 1930-40, 1940-50, …, 1990-2000

20-year periods: 1930-50, 1940-60, …, 1980-2000

30-year periods: 1930-1960 vs 1970-2000

RESULTS

Changes in Rainfall (mm Trimester / year)

Linear regression Analysis


Linear regression Analysis

Significant Slopes(P<0.10)

Summary by Trimester

Winter

Spring

Summer

Comparing two Periods:

1930-1960 vs 1970-2000

Changes in Temperatures

Mean monthly T MaxMean monthly T Min

Regression Analysis

JFM

T Min T Min

MJJ

JFM JJA

T Max T Max

Comparing two Periods:

1930-1960 vs 1970-2000

T Max: 1931-1960 vs 1970-2000(Summer 1931-1960)

T Max: 1931-1960 vs 1970-2000(Summer 1970-2000)

T Min: 1931-1960 vs 1970-2000(Winter 1931-1960)

T Min: 1931-1960 vs 1970-2000(Winter 1970-2000)

T Min: 1931-1960 vs 1970-2000(Summer 1931-1960)

T Min: 1931-1960 vs 1970-2000(Summer 1970-2000)

Relevance for

Agricultural Production:

Frost Regime

Changes in dates of first and last frosts

50

100

150

200

250

300

350

1905 1915 1925 1935 1945 1955 1965 1975 1985 1995 2005

Day of the year

First-UY

Last-UY

First-AR

Last-AR

7 Jun 14 Jun

14 Sep

21 Aug

17 Apr

13 May

20 Oct

18 Sep

UY = EstanzuelaAR = Pergamino

Location Date of First FrostDate of Last Frost Frost Period Days with frost Mean Frost Temp

1930 2000 1930 2000 1930 2000 1930 2000 1930 2000AR-Azul 99 109 314 298 215 189 69 63 -0.7 -0.9

AR-Cordoba 122 140 270 248 148 109 42 23 -0.8 -0.3

AR-Pergamino 107 133 293 261 187 127 49 33 -0.6 -0.2

AR-SRosa 82 114 312 278 231 163 79 52 -1.2 -1.0

AR-TArroyos 119 113 305 300 187 186 53 46 -0.1 -0.4

BR-Pelotas 177 166 218 211 41 45 6 4 0.9 0.7

BR-PFundo 159 152 231 233 72 81 8 8 0.2 0.4

UY-Estanzuela 158 165 257 233 98 68 20 7 0.5 0.9

UY-Mercedes 143 138 261 270 118 133 21 31 0.1 -0.4

UY-Paysandu 136 163 267 241 131 78 27 11 -0.5 0.6

Numbers in bold were obtained from regressions that were significant at the p<0.1 levelAR = Argentina, BR = Brazil, UY = Uruguay

Changes in frost regime estimated with regressions (1930-2000)

Location Date of First FrostDate of Last Frost Frost Period Days with frost Mean Frost Temp

1930 2000 1930 2000 1930 2000 1930 2000 1930 2000AR-Azul 99 109 314 298 215 189 69 63 -0.7 -0.9

AR-Cordoba 122 140 270 248 148 109 42 23 -0.8 -0.3

AR-Pergamino 107 133 293 261 187 127 49 33 -0.6 -0.2

AR-SRosa 82 114 312 278 231 163 79 52 -1.2 -1.0

AR-TArroyos 119 113 305 300 187 186 53 46 -0.1 -0.4

BR-Pelotas 177 166 218 211 41 45 6 4 0.9 0.7

BR-PFundo 159 152 231 233 72 81 8 8 0.2 0.4

UY-Estanzuela 158 165 257 233 98 68 20 7 0.5 0.9

UY-Mercedes 143 138 261 270 118 133 21 31 0.1 -0.4

UY-Paysandu 136 163 267 241 131 78 27 11 -0.5 0.6

Numbers in bold were obtained from regressions that were significant at the p<0.1 levelAR = Argentina, BR = Brazil, UY = Uruguay

Changes in frost regime estimated with regressions (1930-2000)

2000 compared to 1930:•Frost period starts later and ends earlier•Less number of frosts in the frost period•Mean temperature of frosts is higher

Changes in absolute and in mean TMax and TminEstimated with Regressions (1930 – 2000)

Location Max T Max Min T Min Mean T Max Mean T Min

1930 2000 1930 2000 1930 2000 1930 2000AR-Azul 46.0 33.7 -5.5 -6.5 20.4 20.8 7.5 8.1

AR-Cordoba 41.1 37.5 -6.3 -4.3 24.7 23.6 10.0 11.8

AR-Pergamino 38.2 37.3 -5.9 -4.2 22.5 22.7 9.2 10.9

AR-SRosa 41.2 38.3 -8.9 -7.1 22.7 22.4 7.8 9.2

AR-TArroyos 40.2 36.0 -4.2 -4.8 21.3 20.2 8.3 8.8

BR-Pelotas 36.8 36.3 -0.1 -0.3 23.0 22.8 13.1 13.9

BR-PFundo 34.6 34.3 -0.7 -1.2 23.7 23.6 12.9 13.4

UY-Estanzuela 38.9 36.3 -1.6 -0.7 21.9 21.6 10.7 12.1

UY-Mercedes 40.4 37.5 -3.6 -3.5 23.3 24.2 10.9 12.1

UY-Paysandu 39.8 38.3 -4.5 -1.1 24.0 23.9 11.0 12.8

Numbers in bold were obtained from regressions that were significant at the p<0.1 level

AR = Argentina, BR = Brazil, UY = Uruguay

Changes in absolute and in mean TMax and TminEstimated with Regressions (1930 – 2000)

2000 compared to 1930:

Absolute TMax and Mean TMax are lower Absolute TMin and Mean TMin are higher

Location Max T Max Min T Min Mean T Max Mean T Min

1930 2000 1930 2000 1930 2000 1930 2000AR-Azul 46.0 33.7 -5.5 -6.5 20.4 20.8 7.5 8.1

AR-Cordoba 41.1 37.5 -6.3 -4.3 24.7 23.6 10.0 11.8

AR-Pergamino 38.2 37.3 -5.9 -4.2 22.5 22.7 9.2 10.9

AR-SRosa 41.2 38.3 -8.9 -7.1 22.7 22.4 7.8 9.2

AR-TArroyos 40.2 36.0 -4.2 -4.8 21.3 20.2 8.3 8.8

BR-Pelotas 36.8 36.3 -0.1 -0.3 23.0 22.8 13.1 13.9

BR-PFundo 34.6 34.3 -0.7 -1.2 23.7 23.6 12.9 13.4

UY-Estanzuela 38.9 36.3 -1.6 -0.7 21.9 21.6 10.7 12.1

UY-Mercedes 40.4 37.5 -3.6 -3.5 23.3 24.2 10.9 12.1

UY-Paysandu 39.8 38.3 -4.5 -1.1 24.0 23.9 11.0 12.8

Numbers in bold were obtained from regressions that were significant at the p<0.1 level

AR = Argentina, BR = Brazil, UY = Uruguay

Reported Changes in Means

Changes in Variability?

Changes in mean values (DJF)

050

100150200250

300350400450500

UYLE UYMC UYPY BRPF BRPE ARAZ ARPE ARCO ARTA ARSR

Rainfall (mm per trimester)

1930 - 19641965 - 2000

Changes in mean values (MAM)

0

50

100

150

200

250

300

350

400

450



1930 - 19641965 - 2000

Changes in mean values (JJA)

050

100150200250

300350400

450500



1930 - 19641965 - 2000

Changes in mean values (SON)

0

100

200

300

400

500

600



1930 - 19641965 - 2000

Changes in Standard Deviation (DJF)

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

180.0


SD (mm per trimester)

1930 - 19641965 - 2000

Changes in Standard Deviation (MAM)

0.0

20.0

40.0

60.0

80.0

100.0

120.0

140.0

160.0

180.0



1930 - 19641965 - 2000

Changes in Standard Deviation (JJA)

0.020.0

40.060.0

80.0100.0120.0

140.0160.0

180.0200.0



1930 - 19641965 - 2000

Changes in Standard Deviation (SON)

0.020.0

40.060.0

80.0100.0

120.0140.0

160.0180.0

200.0



1930 - 19641965 - 2000

7+, 2-, 1= 3+, 3-, 4=

4+, 4-, 2=

5+, 5=

Conclusions

Increased Rainfall in Spring and SummerBetter for pastures, summer crops but animal / crop diseases? pests?(M. Fernandes’ presentation)

Increased Rainfall Variability in Summer (?)(higher risk)

Decreased Mean T Max (Spring and Summer)

Increased Mean T Min (all year)

Shorter frost period (first – last dates)Less number of days with frost Frosts became less severe (Temp is higher)

Changes in the Coefficient of Variation (DJF)

0.0

10.0

20.0

30.0

40.0

50.0

60.0


CV (%) per trimester

1930 - 19641965 - 2000

Changes in the Coefficient of Variation (MAM)

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0



1930 - 19641965 - 2000

Changes in the Coefficient of Variation (JJA)

0.010.0

20.030.0

40.050.0

60.070.0

80.090.0

100.0



1930 - 19641965 - 2000

Changes in the Coefficient of Variation (SON)

0.0

5.010.0

15.020.0

25.0

30.035.0

40.045.0

50.0



1930 - 19641965 - 2000

observed changes in climatic variables relevant for agricultural production during 1930-2000 in the...

Documents

trimester yearchanges

trimester yearsummary

project changes

year periods

different periods

frost regimeuy

frost periodmean temperature

entire period