cost es0601 temperature network 000001 michele brunetti (m.brunetti@isacr.it)

COST ES0601COST ES0601

Temperature Network 000001Temperature Network 000001

Michele BRUNETTI

(m.brunetti@isac.cnr.it)

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