Supplement of Earth Syst. Dynam., 11, 793–805, 2020https://doi.org/10.5194/esd-11-793-2020-supplement© Author(s) 2020. This work is distributed underthe Creative Commons Attribution 4.0 License.

Supplement of

Compound warm–dry and cold–wet events over the MediterraneanPaolo De Luca et al.

Correspondence to: Paolo De Luca (p.deluca@vu.nl)

The copyright of individual parts of the supplement might differ from the CC BY 4.0 License.

1 Supplementary DataTo improve the robustness of our results we make use of two additional reanalysis datasets from the European Centre for

Medium-Range Weather Forecasts (ECMWF) over the 1979-2018 period. These are: ERA-Interim with horizontal resolution

of 0.75◦ (Dee et al., 2011) and ERA5 10-member ensemble (0.5◦) (C3S, 2017), hereafter termed "ERA5 ensemble". The

Mediterranean (MED) domain follows the "Full Mediterranean (FMED)" region described in Giorgi and Lionello (2008). For5

ERA-Interim, we use 27.75–48.00 ◦N, 9.75 ◦W–39.00 ◦E, whereas for the ERA5 ensemble we use 28.00–48.00 ◦N, 9.50W–

39.00 ◦E. To study compound events, we compute daily Tmax, Tmin and P, based on 6- and 3-hourly data from ERA5 ensemble

respectively for Tmax (Tmin) and P, and 12-hourly data from ERA-Interim. We also use daily-mean SLP values, computed

by averaging 6-hourly ERA-Interim and ERA5 ensemble data. For ERA5 ensemble, we compute the 10-member ensemble

mean for all the dynamical systems metrics and variables of interest. It is important to note that the dynamical systems metrics10

are first computed on the individual ensemble members and then their values averaged for the trend analyses, whereas for the

composite maps we first compute the composite for each ensemble member and then we average them. Lastly, we also use

ERA5 daily mean convective available potential energy (CAPE, JKg−1) and ERA5 daily snowfall (mm), the former computed

by averaging daily 6-hourly steps and the latter by summing the 1-hourly time-steps as for P. We note that Tmax (Tmin), SLP

and CAPE are obtained from instantaneous values, whereas P and snowfall from forecasted fields.15

2

2 Supplementary Figures

JJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJA ERA−Interim slope=8e−04, p−val

DJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJFDJF ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA5 slope=1e−04, p−val=0.357ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279ERA−Interim slope=1e−04, p−val=0.279

ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258ERA5 ensemble slope=2e−04, p−val=0.258

0.055

0.065

0.075

0.085

0.095

0.105

0.115

0.125

1979 1983 1987 1991 1995 1999 2003 2007 2011 2015Time (years)

α

ERA5 ERA−Interim ERA5 ensemble

Figure S2. As Figure 1a but for winter December-January-February (DJF) and α computed from Tmin and P.

4

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0.10 0.11 0.12 0.13 0.14

300.

530

1.5

302.

5(b) ERA−Interim JJA rho=0.74, p−val=0, R^2=0.59

alpha

tem

p m

ax (K

)

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0.10 0.11 0.12 0.13 0.14 0.15

299.

530

0.5

301.

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(c) ERA5 ensemble JJA rho=0.72, p−val=0, R^2=0.56

alpha

tem

p m

ax (K

)

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0.09 0.10 0.11 0.12 0.13 0.14 0.15

299.

530

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301.

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(a) ERA5 JJA rho=0.79, p−val=0, R^2=0.66

alpha

tem

p m

ax (K

)

Figure S3. Linear regressions and Spearman’s correlation tests between JJA mean Tmax and JJA co-recurrence ratio (α) within the 1979-

2018 period over the MED. (a) ERA5; (b) ERA-Interim; and (c) ERA5 ensemble mean. The Spearman’s rho correlation coefficient, relative

p-value and coefficient of determination (R2) are shown for each reanalysis product.

5

JJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJA ERA5 slope=9e−04, p−val

JJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−onlyJJA Land−only ERA5 slope=0.001, p−val

JJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJA ERA−Interim slope=0.0051, p−val

0

100

200

300

400

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

(a)

0

100

200

300

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

(b)

Months

CD

Es

Cou

nt

ERA−Interim ERA5 ensemble

Figure S7. As Figure 3 but for ERA-Interim (blue) and ERA5 ensemble mean (black).

9

−0.25 0.00 0.25 0.50 0.75 1.00SLP (hPa) Anomaly Means

(a) ERA−Interim JJA

−0.25 0.00 0.25 0.50 0.75 1.00SLP (hPa) Anomaly Means

(b) ERA5 ensemble JJA

−0.5 0.0 0.5 1.0 1.5 2.0Tmax (K) Anomaly Means

(c) ERA−Interim JJA

−0.5 0.0 0.5 1.0 1.5 2.0Tmax (K) Anomaly Means

(d) ERA5 ensemble JJA

−1 0 1 2 3P (mm) Anomaly Means

(e) ERA−Interim JJA

−1 0 1 2 3P (mm) Anomaly Means

(f) ERA5 ensemble JJA

Figure S8. As Figure 4a,c,e but for (a), (c), (e) ERA-Interim and (b), (d), (f) ERA5 ensemble mean.

10

−80 0 80 160 240 320CAPE (JKg−1), Anomaly Means

Figure S9. As Figure 4e but for ERA5 daily mean convective available potential energy (CAPE, JKg−1).

11

−4 −2 0 2 4SLP (hPa) Anomaly Means

(a) ERA−Interim DJF

−4 −2 0 2 4SLP (hPa) Anomaly Means

(b) ERA5 ensemble DJF

−2.0 −1.5 −1.0 −0.5 0.0 0.5 1.0Tmin (K) Anomaly Means

(c) ERA−Interim DJF

−2.0 −1.5 −1.0 −0.5 0.0 0.5 1.0Tmin (K) Anomaly Means

(d) ERA5 ensemble DJF

−2 −1 0 1 2 3 4 5 6 7P (mm) Anomaly Means

(e) ERA−Interim DJF

−2 −1 0 1 2 3 4 5 6 7P (mm) Anomaly Means

(f) ERA5 ensemble DJF

Figure S10. As Figure 4b,d,f but for (a), (c), (e) ERA-Interim and (b), (d), (f) ERA5 ensemble mean.

12

−1 0 1 2 3 4Snowfall (mm) Anomaly Means

Figure S11. As Figure 4f, but for snowfall anomaly means (mm).

13

−1.0 −0.5 0.0 0.5SLP (hPa) Anomaly Means

(a) JJA

−4 −3 −2 −1 0SLP (hPa) Anomaly Means

(b) DJF

−0.5 0.0 0.5 1.0 1.5 2.0 2.5 3.0Tmax (K) Anomaly Means

(c) JJA

−2.0 −1.5 −1.0 −0.5 0.0 0.5 1.0Tmin (K) Anomaly Means

(d) DJF

0 2 4 6 8 10 12 14 16 18 20P (mm) Anomaly Means

(e) JJA

0 4 8 12 16 20P (mm) Anomaly Means

(f) DJF

Figure S12. As Figure 4 but for anomalies > 90th and < 10th quantiles.

14

JJA ERA−Interim

0

50

100

150

−1 0 1 2

Cou

nt

(a)

0.00

0.25

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−1 0 1 2

F(x

)JJA ERA−Interim

0

250

500

750

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Cou

nt

(b)

0.00

0.25

0.50

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1.00

−1 0 1 2 3

F(x

)

JJA ERA5 ensemble

0

100

200

300

−1 0 1 2Tmax (K) Anomaly Means

Cou

nt

(c)

0.00

0.25

0.50

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1.00

−1 0 1 2Tmax (K) Anomaly Means

F(x

)

JJA ERA5 ensemble

0

500

1000

1500

−1 0 1 2 3P (mm) Anomaly Means

Cou

nt(d)

0.00

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0.50

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1.00

−1 0 1 2 3P (mm) Anomaly Means

F(x

)

Figure S13. As Figure 5a-b but for (a)-(b) ERA-Interim (blue) and (c)-(d) ERA5 ensemble mean (black). The anomaly means correspond to

the ones in Figure S8c-f.

15

DJF ERA−Interim

0

30

60

90

−2 −1 0 1

Cou

nt

(a)

0.00

0.25

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−2 −1 0 1

F(x

)DJF ERA−Interim

0

100

200

300

400

−2 0 2 4 6 8

Cou

nt

(b)

0.00

0.25

0.50

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−2 0 2 4 6 8

F(x

)

DJF ERA5 ensemble

0

100

200

300

−2 −1 0 1Tmin (K) Anomaly Means

Cou

nt

(c)

0.00

0.25

0.50

0.75

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−2 −1 0 1Tmin (K) Anomaly Means

F(x

)

DJF ERA5 ensemble

0

250

500

750

1000

−2 0 2 4 6 8P (mm) Anomaly Means

Cou

nt(d)

0.00

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0.50

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1.00

−2 0 2 4 6 8P (mm) Anomaly Means

F(x

)

Figure S14. As Figure 5c-d but for (a)-(b) ERA-Interim (blue) and (c)-(d) ERA5 ensemble mean (black). The anomaly means correspond to

the ones in Figure S10c-f.

16

10 20 30 40 50 60 70JJA Warm−Dry %

(a) ERA−Interim

10 20 30 40 50 60 70JJA Warm−Dry %

(b) ERA5 ensemble

Figure S15. As Figure 6a but for (a) ERA-Interim and (b) ERA5 ensemble mean.

17

10 20 30 40DJF Cold−Wet %

(a) ERA−Interim

10 20 30 40DJF Cold−Wet %

(b) ERA5 ensemble

Figure S16. As Figure 6b but for (a) ERA-Interim and (b) ERA5 ensemble mean.

18

JJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJAJJA ERA5 slope=0.001, p−val

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