DATA AND METADATA FOR THE CENTRAL
PART OF THE MEDITERRANEAN BASIN:
LESSONS FROM THE CLIMAGRI PROJECT
Maurizio Maugeri
Istituto di Fisica Generale Applicata – via Celoria 16 – Milano
Istituto di Scienze dell'Atmosfera e del Clima – via Gobetti 101 - Bologna
[email protected]
Tarragona – November 28th, 2007
Italy has a very important role in the development
of meteorological observations
Invention of some of the most important meteorological
instruments (thermometer, barometer).
Establishment of the first network of observations (rete
del Cimento, set up by Galileo’s scholars).
The strong Italian presence in the development of meteorological
observations is also testified by six stations that have been in
operation since the eighteenth century (Bologna, Milan, Rome, Padua,
Palermo and Turin) and other 15 stations where observations started
in the first half of the nineteenth century (Aosta, Florence, Genoa,
Ivrea, Locorotondo, Mantua, Naples, Parma, Pavia, Perugia, Trento,
Trieste, Udine, Urbino and Venice).
As a consequence, a heritage of
data of enormous value has
been accumulated in Italy over
the last three centuries
This heritage has been known for a long time and
many attempts have been made to collect data into a
meteorological archive…..
Cantù V. and Narducci P. (1967) Lunghe serie di osservazioni
meteorologiche. Rivista di Meteorologia Aeronautica, Anno
XXVII, n. 2, 71-79.
Eredia F. (1908) Le precipitazioni atmosferiche in Italia dal 1880 al
1905. In: Annali dell'Ufficio Centrale di Meteorologia. Serie II,
Vol. XXVII, anno 1905, Rome.
Eredia F. (1919) Osservazioni pluviometriche raccolate a tutto l'anno
1915 dal R. Ufficio Centrale di Meteorologia e Geodinamica.
Ministero dei Lavori Pubblici, Rome.
Eredia F. (1925) Osservazioni pluviometriche raccolate nel
quinquennio 1916-1920 dal R. Ufficio Centrale di Meteorologia
e Geodinamica. Ministero dei Lavori Pubblici, Rome.
Mennella C. 1967. Il Clima d'Italia. Napoli: Fratelli Conti Editori, 724
pp.
Millosevich (1882) Sulla distribuzione della pioggia in Italia. In:
Annali dell'Ufficio Centrale di Meteorologia. Serie II, Vol. III,
anno 1881, Rome.
Millosevich (1885) Appendice alla memoria sulla pioggia in Italia. In:
Annali dell'Ufficio Centrale di Meteorologia. Serie II, Vol. V,
anno 1883, Rome.
Narducci, P., 1991: Bibliografia Climatologica Italiana, Consiglio
Nazionale dei Geometri, Roma.
… however, in spite of the huge heritage of data and even if
most records were subjected to some sort of analysis, until a
few years ago only a small fraction of Italian data was
available in computer readable form
Precipitazioni
Stazione
Reggio Calabria
Palermo
Perugia
Torino
Padova
Alessandria
Arezzo
Belluno
Rovigo
L’Aquila
Reggio Emilia
Napoli
Cagliari
Mantova
Sassari
Siracusa
Roma
Pesaro
Bologna
Ferrara
Parma
Piacenza
Pavia
Cuneo
Messina
Livorno
Temperature
Lunghezza serie
Dati mancanti
(%)
Lunghezza serie
Dati mancanti
(%)
1878-1972
1874-1973
1874-1973
1866-1969
1877-1968
1875-1970
1879-1972
1879-1986
1879-1976
1879-1973
1879-1970
1865-1969
1879-1971
1880-1973
1876-1971
1874-1973
1862-1999
1876-1992
1879-1988
1879-1974
1878-1994
1875-1999
1883-1991
1879-1993
1881-1974
1876-1994
19.8
0.7
21.2
10.2
5.0
16.8
17.7
7.7
12.4
8.5
10.8
2.7
4.0
11.5
12.1
12.5
6.2
11.6
10.3
17.9
6.3
6.0
23.8
12.5
12.2
10.3
1878-1972
1876-1973
1876-1973
1870-1969
1877-1968
1878-1970
1879-1972
1879-1966
1879-1966
1879-1973
1879-1970
1870-1969
1879-1971
1880-1973
1876-1971
1878-1973
1870-1999
1876-1992
1879-1988
1879-1974
1878-1994
1878-1999
1870-1979
1879-1993
1881-1974
1870-1994
19.2
0.1
1.3
17.9
4.7
14.7
19.0
6.9
13.0
15.2
23.8
9.3
2.5
11.4
8.8
11.4
0.4
7.8
14.8
16.6
2.5
9.4
26.1
12.4
10.7
11.8
Archivio delle serie secolari UCEA - Anzaldi C., Mirri L. and Trevisan V., 1980: Archivio Storico delle osservazioni
meteorologiche, Pubblicazione CNR AQ/5/27, Roma.
Within this context, a number of projects where set
up in Italy in the last 5 to 10 years to recovery as
much as possible secular meteorological records
The activities can be clustered in two general classes
Projects concerning single stations
High temporal resolution, complete metadata documentation, etc…
Projects concerning national/regional networks
Lower temporal resolution, less metadata, etc…
Projects concerning single stations are particularly
important for the records beginnig in the 18th century
Milan: a 10-year project developed
Padova: as for Milan but activities
by Osservatorio Astronomico di
performed by Istituto di Scienze
Milano-Brera and Milan University
dell'Atmosfera e del Clima – section
allowed to recovery metadata and
of Padova
daily T, P, R records
Palermo: recovery started later on;
Torino: as for Milan and Padova
The activities are performed by Os.
but activities performed by Società
Astronomico. Available: metadata
Meteorologica Italiana
and daily R and T records.
Bologna: as for Milan, Padova and
Roma: as for Milan, Padova and
Torino for the data after 1813. Still Torino for the data after 1862. Only
in progress for the 18th century data monthly data for the 18th century
…there is a lot of still unexploited information…
Cloudiness, sunshine, vapour pressure, wind, etc…
Projects concerning national/regional networks
Second part of the 1990s: the CNR project “Reconstruction of the past
climate in the Mediterranean area” allowed the UCEA secular series
data set to be updated, completed, and revised. In spite of significant
improvements, the new data set had the fundamental limitation of very
poor metadata availability. Moreover, the number of stations was still too
low. So homogenisation could not be performed.
Around 2000 a new research programme was established. It was initially
developed within a national project (CLIMAGRI), then an extension of
the activities was performed within some other projects.
Thanks to the availability of resources from more projects and to
additional results from other projects, the initial goal of homogenising
the existing records was extended and the construction of a completely
new and larger set of data and metadata was also planned.
The new dataset of Italian secular records
Meteorological variables
• Air Temperature (minimum, mean, maximum)
• Precipitation
• Air Pressure
• Cloud Cover
• Other data
Temporal resolution
Daily/Monthly
The new Italian dataset: air temperature
STATION
CODE
LON (º)
LAT (º)
z (m)
ALESSANDRIA
AOSTA
L'AQUILA
AREZZO
BELLUNO
BOLOGNA
BOLZANO
BRÁ
BRIXEN
CAGLIARI
CASTROVILLARI
CATANIA
CHIAVARI
COSENZA
CATANZARO
CUNEO
DOMODOSSOLA
FERRARA
FIRENZE
FOGGIA
FOSSANO
GENOVA
IMPERIA
LIVORNO
LOCARNO
LUGANO
MANTOVA
MESSINA
MILANO
MONTE MARIA
NAPOLI
NIZZA
PADOVA
PALERMO
PARMA
PAVIA
PERUGIA
PESARO
PIACENZA
POTENZA
POLA
REGGIO CALABRIA
REGGIO EMILIA
RIVA TORBOLE
ROVERETO
ROMA
ROVIGO
ROSSANO
SASSARI
SAN BERNARDO
SIRACUSA
TARANTO
TORINO MONCALIERI
TORINO
TORTONA
TRENTO
TRIESTE
TROPEA
UDINE
VALLOMBROSA
VALSINNI
VENEZIA
ALE
AOS
AQU
ARE
BEL
BOL
BOZ
BRA
BRI
CAG
CAR
CAT
CHA
COS
CTA
CUN
DOM
FER
FIR
FOG
FOS
GEN
IMP
LIV
LOC
LUG
MAN
MES
MIL
MMA
NAP
NIZ
PAD
PAL
PAR
PAV
PER
PES
PIA
POT
PUL
RCA
REM
RIV
ROE
ROM
ROV
RSS
SAS
SBE
SIR
TAR
TOM
TOR
TOT
TRE
TRI
TRO
UDI
VAL
VAS
VEN
8.63
7.30
13.40
12.00
12.25
11.25
11.33
7.87
11.65
9.15
16.20
15.11
9.30
16.25
16.58
7.50
8.27
11.50
11.30
15.52
8.38
9.00
8.02
10.25
8.79
8.97
10.75
15.50
9.00
10.49
14.25
7.20
11.75
13.35
10.25
9.25
12.50
13.00
9.75
15.82
13.87
15.65
10.75
10.83
11.05
12.47
11.75
16.62
8.60
7.18
15.28
17.30
7.70
7.75
8.87
11.12
13.75
15.88
13.20
11.00
16.42
12.25
44.92
45.73
42.35
43.45
46.12
44.48
46.50
44.70
46.72
39.20
39.80
37.50
40.30
39.28
38.90
44.40
46.10
44.82
43.80
41.45
44.57
44.40
43.87
43.55
46.17
46.00
45.15
38.20
45.47
46.74
40.88
43.65
45.40
38.10
44.80
45.17
43.10
43.87
45.02
40.63
44.86
38.10
44.70
45.88
45.87
41.90
45.05
39.55
40.72
45.87
37.05
40.45
45.00
45.05
44.88
46.07
45.65
38.67
46.00
43.72
40.15
45.43
98
544
753
274
404
60
272
290
569
55
353
75
5
250
343
536
300
15
51
80
351
21
54
3
379
276
51
54
64
1323
149
4
14
71
57
75
520
11
50
826
30
15
62
70
206
56
9
300
224
2472
23
22
238
275
199
199
11
51
51
955
250
21
Min/Max
(daily)
1854-1985
1879-2003
1879-2003
1879-2003
1814-2003
1879-2003
1925-2002
1901-2003
1925-2002
1924-2002
1879-2003
1879-2003
1889-2003
1901-2003
1833-2003
1870-2001
1828-2003
1881-2003
1763-2003
1870-2003
1774-2003
1876-2003
1878-2003
1870-2002
1876-2003
1871-2003
1878-2003
1924-2002
1878-2002
1879-2003
1862-2003
1879-2003
1925-1997
1876-2003
1878-2003
1901-2003
1753-2003
1924-2002
1872-2003
1924-2002
1900-2002
Min/Max
(monthly)
1854-1985
1891-2003
1869-2003
1876-2003
1875-2003
1814-2003
1879-2003
1925-2002
1901-2003
1925-2002
1924-2002
1879-2003
1865-2003
1878-2003
1901-2003
1833-2003
1875-2003
1865-2001
1935-1997
1901-1997
1828-2003
1881-2003
1763-2003
1865-2003
1774-2003
1876-2003
1872-2003
1865-2002
1865-2003
1871-2003
1871-2003
1924-2002
1878-2002
1866-2003
1862-2003
1879-2003
1925-1997
1874-2003
1878-2003
1901-2003
1865-2003
1753-2003
1883-2003
1924-2002
1803-2003
1872-2003
1924-2002
1900-2002
Mean
(monthly)
1854-1985
1840-2003
1869-2003
1876-2003
1875-2003
1814-2003
1850-2003
1862-1970
1865-2003
1879-2003
1925-2002
1901-2003
1883-2002
1925-2002
1924-2002
1879-2003
1872-1997
1865-2003
1878-2003
1901-2003
1874-1973
1833-2003
1875-2003
1865-2001
1864-1997
1864-1997
1828-2003
1881-2003
1763-2003
1857-2003
1865-2003
1806-2003
1774-2003
1876-2003
1872-2003
1861-2002
1865-2003
1871-2003
1871-2003
1924-2002
1864-2003
1878-2002
1866-2003
1869-2003
1862-2003
1862-2003
1879-2003
1925-1997
1874-2003
1818-1998
1878-2003
1901-2003
1864-2003
1753-2003
1892-1965
1816-2003
1841-2003
1924-2002
1803-2003
1872-2003
1924-2002
1900-2002
The new Italian dataset: air temperature
The new Italian dataset: precipitation
STATION
CODE
LON (º)
LAT (º)
z (m)
ALESSANDRIA
ANDRIA
AOSTA
L'AQUILA
AREZZO
ASTI
BARLETTA
BALMÈ
BARDONECCHIA
BELLUNO
BENEVENTO
BOLOGNA
BORGOMANERO
BOLZANO
BRÁ
BRIXEN
BRINDISI
CASTELLANETA
CAGLIARI
CANOSA
CASALE MONFERRATO
CATANIA
CAVOUR
CENTALLO
CERIGNOLA
CHIVASSO
COSENZA
CRISPIANO
CROTONE
CATANZARO
CUNEO
DOMODOSSOLA
FENESTRELLE
FERRARA
FIRENZE
FOGGIA
FOSSANO
GALATINA
GALLIPOLI
GENOVA
GINOSA
GINOSA SCALO
IMPERIA
IVREA
LATIANO
LECCE
LESINA
LIVORNO
LIZZANO
LOCARNO
LOMBRIASCO
LOCOROTONDO
LUGANO
MANFREDONIA
MAGLIE
MANTOVA
ALE
AND
AOS
AQU
ARE
AST
BAE
BAL
BAR
BEL
BEN
BOL
BOR
BOZ
BRA
BRI
BRN
CAE
CAG
CAO
CAS
CAT
CAV
CEN
CER
CHI
COS
CRI
CRO
CTA
CUN
DOM
FEN
FER
FIR
FOG
FOS
GAL
GAP
GEN
GIN
GIS
IMP
IVR
LAT
LEC
LES
LIV
LIZ
LOC
LOM
LOR
LUG
MAF
MAG
MAN
8.63
16.28
7.30
13.40
12.00
8.20
16.27
7.22
6.70
12.25
14.80
11.25
8.45
11.33
7.87
11.65
17.93
16.93
9.15
15.90
8.50
15.11
7.37
7.60
15.88
7.85
16.25
17.23
17.12
16.58
7.50
8.27
7.06
11.50
11.30
15.52
8.38
18.15
17.98
9.00
16.75
16.75
8.02
7.91
17.72
18.17
15.35
10.25
17.45
8.79
7.65
17.33
8.97
15.92
18.30
10.75
44.92
41.23
45.73
42.35
43.45
44.90
41.33
45.32
45.08
46.12
41.12
44.48
45.70
46.50
44.70
46.72
40.65
40.63
39.20
41.13
45.13
37.50
44.73
44.50
41.27
45.17
39.28
40.60
39.08
38.90
44.40
46.10
45.04
44.82
43.80
41.45
44.57
40.17
40.05
44.40
40.58
40.58
43.87
45.46
40.55
40.35
41.87
43.55
40.38
46.17
44.84
40.75
46.00
41.62
40.12
45.15
98
151
544
753
274
158
20
1432
1340
404
177
60
317
272
290
569
28
245
55
154
113
75
290
417
124
221
250
265
6
343
536
300
1200
15
51
80
351
73
31
21
257
5
54
267
98
78
5
3
67
379
239
420
276
2
77
51
Precipitation
(daily)
1857-1986
1879-2003
1879-2003
1879-2003
1813-2003
1921-2003
1862-2003
1921-2003
1879-2003
1921-2003
1916-2002
1916-2002
1916-2002
1879-2003
1872-1998
1879-2003
1860-2003
1901-2003
1833-2003
1876-2002
1901-2002
1901-2002
1840-2003
Precipitation
(monthly)
1857-1986
1921-1996
1841-2003
1874-2003
1876-2003
1881-1993
1921-1996
1913-2003
1913-2002
1875-2003
1870-1996
1813-2003
1881-1996
1856-2003
1862-2003
1878-2003
1877-2000
1877-1996
1853-2003
1922-1996
1870-2003
1892-2003
1879-1993
1883-1988
1922-1996
1892-1988
1873-2002
1916-1996
1916-2002
1868-2002
1877-2003
1872-1998
1912-1997
1865-2003
1860-2003
1873-2003
1875-1997
1923-1996
1877-1996
1833-2003
1887-1996
1928-1996
1876-2003
1837-2002
1925-1996
1875-2000
1928-1998
1857-2002
1916-1996
1886-2002
1913-1999
1829-1996
1861-2002
1921-1996
1908-1996
1840-2003
STATION
CODE
LON (º)
LAT (º)
z (m)
MASSAFRA
MATERA
MESSINA
METAPONTO
MILANO
MINERVINO LECCESE
MONTE MARIA
MONCALVO
MONDOVI
NAPOLI
NARDÒ
NIZZA
NOVI LIGURE
NOVOLI
NOVARA
OTRANTO
OVADA
PADOVA
PALERMO
PARMA
PAVIA
PERUGIA
PESARO
PIACENZA
POTENZA
PRESICCE
POLA
REGGIO CALABRIA
REGGIO EMILIA
RIVA TORBOLE
ROVERETO
ROMA
ROVIGO
SASSARI
SAN BERNARDO
SILANDRO
SIRACUSA
SAN MARCO
SAN PIETRO
STROPPO
TARANTO
TAVIANO
TORINO MONCALIERI
TORINO
TORTONA
TRENTO
TRIESTE
TROPEA
UDINE
URBINO
VALLOMBROSA
VARALLO
VENEZIA
VICO GARGANICO
VIESTE
MAS
MAT
MES
MET
MIL
MIN
MMA
MOC
MOD
NAP
NAR
NIZ
NOL
NOO
NOV
OTR
OVA
PAD
PAL
PAR
PAV
PER
PES
PIA
POT
PRE
PUL
RCA
REM
RIV
ROE
ROM
ROV
SAS
SBE
SIL
SIR
SMA
SPI
STR
TAR
TAV
TOM
TOR
TOT
TRE
TRI
TRO
UDI
URB
VAL
VAR
VEN
VIC
VIE
17.12
16.62
15.50
16.82
9.00
18.42
10.49
8.25
7.82
14.25
18.02
7.20
8.78
18.05
8.62
18.50
8.65
11.75
13.35
10.25
9.25
12.50
13.00
9.75
15.82
18.27
13.87
15.65
10.75
10.83
11.05
12.47
11.75
8.60
7.18
10.77
15.28
15.62
18.13
7.12
17.30
18.08
7.70
7.75
8.87
11.12
13.75
15.88
13.20
12.62
11.00
8.25
12.25
15.95
16.17
40.58
40.68
38.20
40.37
45.47
40.08
46.74
45.05
44.04
40.88
40.18
43.65
44.78
40.38
45.45
40.13
44.62
45.40
38.10
44.80
45.17
43.10
43.87
45.02
40.63
39.90
44.86
38.10
44.70
45.88
45.87
41.90
45.05
40.72
45.87
46.63
37.05
41.72
40.30
44.50
40.45
39.98
45.00
45.05
44.88
46.07
45.65
38.67
46.00
43.72
43.72
45.82
45.43
41.90
41.88
116
401
54
3
64
98
1323
297
44
149
43
4
186
37
181
52
187
14
71
57
75
520
11
50
826
114
30
15
62
70
206
56
9
224
2472
706
23
560
160
1087
22
61
238
275
199
199
11
51
51
451
955
454
21
450
25
Precipitation
(daily)
1916-2002
1881-2003
1918-2000
1858-2003
1923-2003
1866-2003
1877-2002
1797-2003
1878-2003
1873-2002
1874-2003
1871-2003
1875-2003
1916-2002
1878-2002
1879-2003
1921-2003
1921-2003
1862-2003
1879-2003
1876-2003
1921-1999
1874-2003
1901-2003
1802-2003
1921-2003
1916-2002
1916-2000
1872-2003
1900-2003
-
Precipitation
(monthly)
1881-1997
1916-2002
1866-2003
1918-2000
1764-2003
1926-1996
1858-2003
1889-1988
1866-1995
1821-2003
1923-1996
1865-2002
1880-1979
1924-1996
1875-1996
1879-1996
1913-1996
1750-2002
1797-2003
1833-2003
1812-2002
1811-2003
1866-2003
1872-2003
1879-2002
1877-1996
1864-2002
1877-2002
1867-2003
1869-2003
1864-2003
1782-2003
1878-2003
1876-2003
1864-1997
1921-1999
1869-2003
1921-1998
1923-1996
1913-1996
1877-2003
1885-1996
1864-2003
1802-2003
1873-1998
1864-2003
1841-2003
1916-2002
1803-2003
1850-2000
1872-2003
1871-1995
1836-2003
1922-1998
1921-1998
The new Italian dataset: precipitation
The new Italian dataset: other variables
… the activities are still in progress (e.g. EU project ALP-IMP).
They concern air pressure, cloud cover, humidity and snow…
AIR PRESSURE
(secular records)
TRE
LUG
TRE
GRE
TRI
MIL
TOR
TOM
CLOUD COVER
(secular records)
MIL
PAD VEN
MAN
PIA
TOR
MAN
PIA
FER
PAR
BOL
GEN
FIR
BOL
PES
PES
LIV
LIV
TER
TER
PEC
ROM
ROM
MOV
FOG
FOG
BAI
NAP
SAS
NAP
SAS
LEC
CAR
CAG
LEC
CAR
CAG
TRO
PAL
TRO
MES
RCA
TRA
CAT
HUMIDITY (i.e. dry / wet temperatures)
daily data
2 records
PAL
MES
RCA
CAT
SNOW (HS: snow at ground; HN: fresh snow)
daily / monthly data
About 15 records of northern Italy
1951-2004 PERIOD:
All variables available in digital format
Italian Air Force data-set.
SECULAR RECORDS
DOM ODOSSOLA
TORINO
LUGANO
M ILANO
PADOVA
VENEZIA
TRENTO
TRIESTE
PARM A
PIACENZA
M ANTOVA
BOLOGNA
GENOVA
PESARO
FIRENZE
LIVORNO
TERAM O - ANCONA
ROM A
CAGLIARI - CARLOFORTE
SASSARI
BARI
LECCE
FOGGIA
NAPOLI
M ONTEVERGINE
TROPEA
M ESSINA - REGGIO CALABRIA
PALERM O - TRAPANI
CATANIA
1725
1750
1775
1800
1825
year
1850
1875
1900
1925
1950
The new Italian dataset: metadata
Metadata collection was performed with two main objectives:
i)
to understand the evolution of the Italian meteorological
network
ii) to reconstruct the “history” of all the stations of the data-set.
The research on the history of the single stations was performed both by
analysing a large amount of grey literature and by means of the UCEA archive.
All information was summarized in a card for each data series.
Each card is divided into three parts. In the first part all the information
obtained from the literature is reported. In the second part there are abstracts
from the epistolary correspondence between the stations and the Central Office.
In the third part the sources of the data used to construct the record are
summarized.
For full details; see CLIMAGRI project WEB site (www.climagri.it)
The new Italian dataset:
quality and homogeneity issues
The problem: the real climate signal, that we try
to reconstruct studying long (secular) records of
meteorological data, is generally hidden behind nonclimatic noise caused by station relocation, changes in
instruments, changes in observing times, observers,
and observing regulations, algorithms for the
calculation of means and so on.
 climatic time series should not be used for climate
research without a clear knowledge about the state of
the data in terms of quality and homogeneity.
Quality
 Classification of the institutions (Observatory, high
school, etc…)
 Data sources (hand-written original observations; year
books; pre existing data sets, etc…)
 Time resolution (yearly, monthly, daily, etc…)
 Comparison with other records
Homogeneity
Climate variations
Measuring problems
“Signals” in the records of meteorological data
Measuring problems
Relocations
Instrumental errors (changes of the instruments and/or
recalibrations)
Observation methods
Screenings
Changes in the environment around the station
The problem is not easy to manage
Meteorological series can be tested for homogeneity and
homogenised both by direct and indirect methodologies.
The first approach is based on objective information that
can be extracted from the station history or from some
other sources, the latter uses statistical methods,
generally based on comparison with other series.
Both direct and indirect methodologies have severe limits
Direct methodologies are not easy to use as:
1) it is generally very difficult to recover complete
information on the history of the observations (metadata);
2) even if available, metadata hardly give quantitative
estimates of the inhomogeneities in the measures.
Also indirect methodologies have important deficits:
1) they require some hypothesis about the data (e.g.
homogeneous signals over the same region);
2) inhomogeneities and errors are present in all
meteorological series, and so it is often difficult to decide
where to apply corrections and, when the results are not
clear there is a high risk of applying subjective corrections.
How to overcome the intrinsic limit of
indirect homogenisation methods is, at
present, still an open question.
The possibilities range from
homogenising all suspect periods, to
correcting the series only if the results of
the statistical methods are very clear and
also supported by metadata.
So, at present, an universal approach to
manage the problem is lacking.
Our approach:
1) Collecting as much metadata as possible;
2) Performing a first homogenisation by means of
direct methologies;
3) Performing final homogenisation by means of
indirect methologies
Basic problem: what is to correct?
a) All the periods given by statistical methods
b) Only the periods for which there is evidence in metadata
The problem is open
Our methodology:
Wide use of statistical methods
Critical analysis on the light of metadata
The CLIMAGRI project
Important open question: trends critically depend on
the methods used to homogenise the data
North Italy long-term temperature evolution (filtered curves) in the 18761996 period according to Brunetti et al. (2000) and Boehm et al. (2001).
1.0
Po Valley (Boehm et al., 2001)
NITA (Brunetti et al., 1999)
0.8
0.6
0.4
0.2
0.0
-0.2
-0.4
-0.6
-0.8
1984
1972
1960
1948
1936
1924
1912
1900
1888
1876
-1.0
Adapted from: Brunetti, M., Buffoni, L., Maugeri, M., Nanni, T., 2000: Trends of minimum and maximum daily
temperatures in Italy from 1865 to 1996. Theor. Appl. Climatol., 66, 49-60 and Böhm, R., Auer, I., Brunetti, M.,
Maugeri, M., Nanni, T., Schöner W., 2001: Regional Temperature Variability in the European Alps 1760-1998 from
homogenised instrumental time series. Int. J. Climatol., 21, 1779-1801.
Important open question: trends critically depend on
the methods used to homogenise the data
Long-term evolution of summer temperatures in the 1775-2003 period
according to Auer et al. (2007) and Brunetti et al. (2006).
3.0
2.0
1.0
0.0
-1.0
-2.0
Differences between ALPIMP (South) and NITA temperature anomalies - Summer
1999
1991
1983
1975
1967
1959
1951
1943
1935
1927
1919
1911
1903
1895
1887
1879
1871
1863
1855
1847
1839
1831
1823
1815
1807
1799
1791
1783
1775
-3.0