COST ES0601COST ES0601
Temperature Network 000001Temperature Network 000001
Michele BRUNETTI
IIstituto di stituto di SScienze dell'cienze dell'AAtmosfera e del tmosfera e del CClimalima
CONSIGLIO NAZIONALE DELLE RICERCHECONSIGLIO NAZIONALE DELLE RICERCHE
Via P. Gobetti, 101 – 40129 BOLOGNA
TARRAGONA
9-11 March 2009
CRADDOCK TEST CRADDOCK TEST
iiii TTRRss )/(1
-5
0
5
10
15
0 20 40 60 80 100
-10
-5
0
5
10
0 20 40 60 80 100
-10
-5
0
5
10
0 20 40 60 80 100
-50
0
50
100
150
0 20 40 60 80 100
AB
Where is the in homogeneity? In A or B?
EXAMPLEEXAMPLE
CORRECTIONCORRECTION
SHIFT
0
0.5
1
1.5
2
2.5
3
3.5
4
0 10 20 30 40 50 60 70 80 90 100
1T
1R 2R
2T
To be corrected
ii TestHomog
)11()22( RTRT
)11()22( RTRTTestHomog ii
RATIOQTestHomog ii
)1/1/()2/2( RTRTQ
)1/1()2/2( RTQRT
)1/1/()2/2( RTRTTestHomog ii
SMOOTHINGSMOOTHING
SMOOTHING OF THE CORRECTING FACTORS
0.6
0.8
1.0
1.2
1.4
JAN
MA
R
MA
Y
JUL
SE
P
NO
V
Lyon (FR) 1841-1864
0.6
0.8
1.0
1.2
1.4
JAN
MA
R
MA
Y
JUL
SE
P
NO
V
Venezia (IT) 1837-1866
0.6
0.8
1.0
1.2
1.4
JAN
MA
R
MA
Y
JUL
SE
P
NO
V
Luzern (CH) 1882-1900
0
20
40
60
80
100
120
140
JAN
MA
R
MA
Y
JUL
SE
P
NO
V
Padova (IT) 1841-1850
0
20
40
60
80
100
120
140
JAN
MA
R
MA
Y
JUL
SE
P
NO
V
Rovereto (IT) 1941-1950
0
20
40
60
80
100
120
140
JAN
MA
R
MA
Y
JUL
SE
P
NO
V
Firenze (IT) 1911-1920
TO IMPROVE THE SIGNAL-TO-NOISE RATIO
TO AVOID NOT IDENTIFIED OUTLIERS
AFFECTING THE ANNUAL CYCLE
ORIGINAL
CORRECT WITHOUT SMOOTHING
CORRECT WITHSMOOTHING
Auer et al., 2005, Int. J. Clim., 25, 139-166
EXAMPLEEXAMPLE
1st January 1933: Changes in the observation times
Unsteadiness in the first derivation of the Craddock function
EXAMPLEEXAMPLE
EXAMPLEEXAMPLE
DAILY HOMOGENIZATIONDAILY HOMOGENIZATION
1st January 1933: Changes in the observation times
Unsteadiness in the first derivation of the Craddock function
DAILY HOMOGENIZATIONDAILY HOMOGENIZATION
The correction coefficients were calculated on monthly bases, then they were fitted with a trigonometric function in order to obtain daily corrections without discontinuities from one month to another.
SERIE GIORNALIERESERIE GIORNALIERE
Only the coherent curves were used to calculate the mean mean correcting factor seriescorrecting factor series
DAILY HOMOGENIZATIONDAILY HOMOGENIZATION
TEMP 000001TEMP 000001
TREND (YEAR)TREND (YEAR)
ORI
TREND (WINTER)TREND (WINTER)
ORI
TREND (SUMMER)TREND (SUMMER)
ORI
SOME STATISTICSSOME STATISTICS
25 OUTLIERS 34 BREAKS
BREAK LOCATIONBREAK LOCATION
JANJAN
FEBFEB
MARMAR
APRAPR
MAYMAY
JUNJUN
JULJUL
AUGAUG
SEPSEP
OCTOCT
NOVNOV
DECDEC
YEARYEAR
ANNUAL CYCLEANNUAL CYCLE
HOM-ORIHOM-ORI
TREND (YEAR)TREND (YEAR)
ORI
HOM
TREND (WINTER)TREND (WINTER)
ORI
HOM
TREND (SUMMER)TREND (SUMMER)
ORI
HOM