Local climate profile

Rodica Tomozeiu, Lucio Botarelli

ARPA –Emilia Romagna

A. Observed : 1951-2010;

B. Future: over the period 2021-2050 and 2071-2099

Season Indices

Winter 10th percentile of Tmin, Frost days

(Tmin<0°), Icing days (Tmax<0°)

Spring 10th percentile of Tmin, 90th percentile of

Tmax Heat wave duration

Summer 90th percentile of Tmax ;Heat wave

duration, Consecutive dry days

Autumn 90th percentile of precipitation, total

amount of precipitation

Periods:

Study area: Bologna

Local climate profile ( vulnerability, risks, opportunities)

Type of analysis:

• evaluation of trends in terms of magnitude and significance;

• analysis of the frequencies of occurrence of extreme events

Climate profile: observed period

Temporal variability of annual anomalies of Tmin and Tmax

Bologna station

-2

-1

0

1

2

3

4

1951 1955 1959 1963 1967 1971 1975 1979 1983 1987 1991 1995 1999 2003 2007

years

T(°

C)

Tmax Tmin

SEASON TREND (°C/DECADE)

TMIN

TREND (°C/DECADE)

TMAX

WINTER (DJF) 0.4* 0.4*

SPRING (MAM) 0.3* 0.2*

SUMMER (JJA) 0.3* 0.3*

Autun (SON) 0.2* 0.3*

YEARLY 0.3* 0.2*

Note: -positive and significant trend in minimum and maximum temperature over the seasons and at annual level; - the increase is more intense during winter and summer seasons

What about extreme of temperature?

Winter temporal variability of frost days- bologna

0

10

20

30

40

50

60

1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010

Years

No

.of

days

Summer Heat waves - Bologna

0

2

4

6

8

10

12

14

1951 1956 1961 1966 1971 1976 1981 1986 1991 1996 2001 2006

years

no

.of

days

Note:

-increasing trend in seasonal heat weaves; the signal is more intense during summer -The signal is more intense after 1990.

Note:

-decreasing trend in Frost days during winter, spring and autumn; the signal is more intense during winter -the signal is more intense after 1990.

increase in the last decade of the maximum number

of consecutive dry days during Summer (1991-2011)

Slighlty decrease in winter, spring and summer precipitation;

Slighlty increase in autumn precipitation

Variability of summer anomalies of precipitation- Bologna

5

Precipitation- variability and changes over the observed period

Temporal varibility of consecutive number of dry days -

Bologna , summer

0

10

20

30

40

50

60

1951 1956 1961 1966 1971 1976 1981 1986 1991 1996 2001 2006

years

no

.of

days

• Global Climate Models (GCM);

• Regional Climate models(RCM)

• Statistical Models (DS)

Climate profile: future period

Scenarios Tools

Future climate scenarios at Bologna constructed with

statistical downscaling

Winter Spring Summer Autumn

Tmin 2021 2050 1.2°C 1.6°C 2.5°C 1.7°C

Tmax 2021 2050 1.5°C 2.1°C 2.5°C 2°C

Tmin 2071-2099 2.8°C 3.7°C 5.5°C 3.4°C

Tmax 2071 2099 3°C 4.1°C 5.5°C 4°C

Climate change projections (EM) of seasonal minimum and maximum temperature at Bologna, over the periods 2021-2050 and 2071-2099.

TEMPERATURE

Probability Density Functions (PDFs) of maximum temperature at

Bologna station during summer season, different periods

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

25 26 27 28 29 30 31 32 33 34 35 36 37 38 39

Tmax (°C)-summer

1961_1990 1980-2009

2021-2050 scenario A1B 2071-2099 scenario A1B

• Decrease in frost and ice days more intense to the end of century

• Increase in heat waves, more intense during summer and to the end of century

Climate change projections of extreme of temperature over 2021-2050 and 2071-2099 with respect to 1961-1990

10

-16

-14

-12

-10

-8

-6

-4

-2

0

DJF MAM SON

chan

ges(

day

s)

EM Tnfd 2021-2050 EM Tnfd 2071-2099

EM Txice 2021-2050 EM Txice 2071-2099

0

2

4

6

8

10

12

DGF MAM GLA SON

HW

D(d

ays)

seasons

clima 1961-1990 hwd_2021-2050 hwd_2071_2099

Frost and ice days Heat waves

Climate change projections of precipitation , over 2021-2050 and 2071-2099 with respect to 1961-1990

a decrease of precipitation over both periods 2021-2050 and 2071-2099, more intense during spring, summer and autumn a possible increase in the maximum number of consecutive dry days , especially during winter spring and summer, and an increase in the summer intense precipitation.

11

-40

-30

-20

-10

0

DGF MAM GLA SON

changes (

%)

seasons

Projected values of changes in mean daily precipitation (%) at Bologna station, outputs of the Ensemble Mean, scenario A1B

2021-2050 2071-2099

Conclusions

•positive and significant trends of seasonal minimum and maximum temperature over the period 1951-2011 (around 0.3°C/decade) have been detected;

•an increase in the heat wave duration , especially during summer, and a decrease in winter frost and ice days has been observed;

• a slightly decrease have been observed for precipitation during winter, spring and summer, while a slightly increase has been noted during autumn.

•a possible increase in the minimum and maximum temperature, around 2°C over the period 2021-2050 with respect to 1961-1990.

• the increase of temperature is more pronounced to the end of the century, and especially during summer , when the anomalies could reach 5.5°C respect to present climate

•a possible increase in the heat wave duration, more intense during summer and to the end of century has been projected

• a reduction of the amount of precipitation has been projected during all seasons, more intense to the end of century and especially during summer season (reduction around 30% ).

Thank you for your kind attention! Rodica Tomozeiu (rtomozeiu@arpa.emr.it) - ARPA- ER Lucio Botarelli (lbotarelli@arpa.emr.it) - ARPA-ER