In this section, we show that the EGP model based on the truncated Beta distribution can be used to model non-zero precipitation, which corresponds to exceedances above the very low threshold of 0, while maintaining the tail behavior.
The daily summer precipitation (May–October) recorded at the Montréal-Trudeau International Airport meteorological station (Québec, Canada) from 2000 to 2020 are investigated. This dataset can be loaded using the ExtendedExtremes.dataset
provided for this tutorial.
data = ExtendedExtremes.dataset("pcp")
filter!(row -> row.Date>= Date(2000,1,1), data)
filter!(row -> month(row.Date) in 5:10, data)
dropmissing!(data)
first(data,5)
1 -73.75 45.47 MONTREAL/PIERRE ELLIOTT TRUDEAU INTL A 7025250 2000-05-01 1.0 2 -73.75 45.47 MONTREAL/PIERRE ELLIOTT TRUDEAU INTL A 7025250 2000-05-02 0.0 3 -73.75 45.47 MONTREAL/PIERRE ELLIOTT TRUDEAU INTL A 7025250 2000-05-03 0.0 4 -73.75 45.47 MONTREAL/PIERRE ELLIOTT TRUDEAU INTL A 7025250 2000-05-04 0.5 5 -73.75 45.47 MONTREAL/PIERRE ELLIOTT TRUDEAU INTL A 7025250 2000-05-05 0.0
The EGP parameter estimation with maximum likelihood is performed with the fit_mle
function.
u = 0.0
y = data.pcp[data.pcp .> u] .- u;
fd = fit_mle(ExtendedGeneralizedPareto{TBeta}, y)
ExtendedGeneralizedPareto{TBeta{Float64}}(
V: TBeta{Float64}(α=0.03797646874817642)
G: GeneralizedPareto{Float64}(μ=0.0, σ=11.75360977328577, ξ=-0.01981634739270602)
)
Several diagnostic plots for assessing the accuracy of the EGP model fitted to the Montréal data are can be shown with the diagnosticplots
function:
set_default_plot_size(16cm, 16cm)
ExtendedExtremes.diagnosticplots(y, fd)
Return Period
10-5
10-4
10-3
10-2
10-1
100
101
102
103
104
105
106
107
108
109
10-4.0
10-3.5
10-3.0
10-2.5
10-2.0
10-1.5
10-1.0
10-0.5
100.0
100.5
101.0
101.5
102.0
102.5
103.0
103.5
104.0
104.5
105.0
105.5
106.0
106.5
107.0
107.5
108.0
10-5
100
105
1010
10-4.0
10-3.8
10-3.6
10-3.4
10-3.2
10-3.0
10-2.8
10-2.6
10-2.4
10-2.2
10-2.0
10-1.8
10-1.6
10-1.4
10-1.2
10-1.0
10-0.8
10-0.6
10-0.4
10-0.2
100.0
100.2
100.4
100.6
100.8
101.0
101.2
101.4
101.6
101.8
102.0
102.2
102.4
102.6
102.8
103.0
103.2
103.4
103.6
103.8
104.0
104.2
104.4
104.6
104.8
105.0
105.2
105.4
105.6
105.8
106.0
106.2
106.4
106.6
106.8
107.0
107.2
107.4
107.6
107.8
108.0
h,j,k,l,arrows,drag to pan
i,o,+,-,scroll,shift-drag to zoom
r,dbl-click to reset
c for coordinates
? for help
?
-100
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-40
-20
0
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60
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100
120
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180
-80
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-5
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-100
0
100
200
-80
-75
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-65
-60
-55
-50
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-30
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-20
-15
-10
-5
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160
Return Level
Return Level Plot
Data
-200
-150
-100
-50
0
50
100
150
200
250
300
350
-120
-110
-100
-90
-80
-70
-60
-50
-40
-30
-20
-10
0
10
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40
50
60
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100
110
120
130
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150
160
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190
200
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240
-200
0
200
400
-120
-115
-110
-105
-100
-95
-90
-85
-80
-75
-70
-65
-60
-55
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
5
10
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25
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55
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240
h,j,k,l,arrows,drag to pan
i,o,+,-,scroll,shift-drag to zoom
r,dbl-click to reset
c for coordinates
? for help
?
-0.5
-0.4
-0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
-0.4
-0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
-0.5
0.0
0.5
1.0
-0.40
-0.38
-0.36
-0.34
-0.32
-0.30
-0.28
-0.26
-0.24
-0.22
-0.20
-0.18
-0.16
-0.14
-0.12
-0.10
-0.08
-0.06
-0.04
-0.02
0.00
0.02
0.04
0.06
0.08
0.10
0.12
0.14
0.16
0.18
0.20
0.22
0.24
0.26
0.28
0.30
0.32
0.34
0.36
0.38
0.40
0.42
0.44
0.46
0.48
0.50
0.52
0.54
0.56
0.58
0.60
0.62
0.64
0.66
0.68
0.70
0.72
0.74
0.76
0.78
0.80
0.82
Density
Density plot
Model
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-100
0
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-80
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-5
0
5
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125
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145
150
155
160
h,j,k,l,arrows,drag to pan
i,o,+,-,scroll,shift-drag to zoom
r,dbl-click to reset
c for coordinates
? for help
?
-100
-80
-60
-40
-20
0
20
40
60
80
100
120
140
160
180
-80
-75
-70
-65
-60
-55
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
5
10
15
20
25
30
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55
60
65
70
75
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85
90
95
100
105
110
115
120
125
130
135
140
145
150
155
160
-100
0
100
200
-80
-75
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-65
-60
-55
-50
-45
-40
-35
-30
-25
-20
-15
-10
-5
0
5
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155
160
Empirical
Quantile Plot
Model
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
-1.0
-0.9
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2.0
-1
0
1
2
-1.00
-0.95
-0.90
-0.85
-0.80
-0.75
-0.70
-0.65
-0.60
-0.55
-0.50
-0.45
-0.40
-0.35
-0.30
-0.25
-0.20
-0.15
-0.10
-0.05
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
1.05
1.10
1.15
1.20
1.25
1.30
1.35
1.40
1.45
1.50
1.55
1.60
1.65
1.70
1.75
1.80
1.85
1.90
1.95
2.00
h,j,k,l,arrows,drag to pan
i,o,+,-,scroll,shift-drag to zoom
r,dbl-click to reset
c for coordinates
? for help
?
-1.5
-1.0
-0.5
0.0
0.5
1.0
1.5
2.0
2.5
-1.0
-0.9
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2.0
-1
0
1
2
-1.00
-0.95
-0.90
-0.85
-0.80
-0.75
-0.70
-0.65
-0.60
-0.55
-0.50
-0.45
-0.40
-0.35
-0.30
-0.25
-0.20
-0.15
-0.10
-0.05
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.55
0.60
0.65
0.70
0.75
0.80
0.85
0.90
0.95
1.00
1.05
1.10
1.15
1.20
1.25
1.30
1.35
1.40
1.45
1.50
1.55
1.60
1.65
1.70
1.75
1.80
1.85
1.90
1.95
2.00
Empirical
Probability Plot
The diagnostic plots consist in the probability plot (upper left panel), the quantile plot (upper right panel), the density plot (lower left panel) and the return level plot (lower right panel). These plots can be displayed separately using respectively the probplot
, qqplot
, histplot
and returnlevelplot
functions.