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Homogeneity Analysis on Surrogate Temperature Data, Network No.1 Palma 25-27 January 2010

Homogeneity Analysis on Surrogate Temperature Data, Network No.1 Palma 25-27 January 2010. lars.andresen@met.no. Work tool: ProClimDB by Petr Stepanek. Procedure Network analysis / Length of data period / Distance between stations / Correlations between stations

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Homogeneity Analysis on Surrogate Temperature Data, Network No.1 Palma 25-27 January 2010

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  1. Homogeneity Analysis onSurrogate Temperature Data, Network No.1Palma 25-27 January 2010 lars.andresen@met.no

  2. Work tool: ProClimDB by Petr Stepanek • Procedure • Network analysis / Length of data period / Distance between stations / Correlations between stations • Quality control / Finding reference stations / Detection of outliers / Correction of original data series • Homogeneity analysis / Finding reference stations / Using SNHT method (Automatic AnClim) / Breaks and adjustments • Adjustments of data series

  3. Network No.1 – analysis 1 Length of data series Distance between stations

  4. Network No.2 – analysis 2 Correlations between stations

  5. ProClimDB Settings

  6. Quality control – 1 • Criterions for making reference series • Maximum 6 stations, • Within distance of 200 km • Maximum altitude difference is 800 m • For consecutive 5-year periods with common data and confidence limit = 0.95 • Observation values are standardized to the altitude of candidate by regression • Outliers check on the difference between observation and reference value (0.99)

  7. Quality control - 2

  8. Homogeneity analysis 1 • Criterions for making reference series for detecting breaks • Maximum 5 stations • Correlation with neigbours above 80% • Maximum altitude difference is 800 m • For 40-year periods (10 years overlap) with common data • Distribution of neighbour values is standardized to the AVG and STD of candidate, for each month • Candidate and reference series are used in the homogenization analysis (SNHT method, automatically analysed in AnClim – results transferred to ProClimDB)

  9. Homogeneity analysis 2 • Breaks • 38 breaks in Network No.1 • For station 050 four breaks: • 1941 • 1951 • 1975 • 1984 • No iterations

  10. Homogeneity analysis 3 • Adjustments (station 050 – no iterations) • 1.procedure • Ref.series for breaks, weigthing on distance (1/d) (power of weights = 0.5). • Maximum adjustment:1.3°C • Number of adjustments: 33 for 12 months • 2.procedure • Ref.series based on up to 10 years around break, minimum 4 years from end (or from another break), 5 nearest stations with distance below 200 km, weigthing on distance (power of weights = 0.5). • Maximum adjustment: 1.0°C • Number of adjustments: 28 for 12 months

  11. Homogeneity analysis 4 – station 050 – 1(ref.series as for detect.breaks) JAN FEB MAR APR MAY JUN JUL AUG SEP OCT NOV DEC Notice scale for JUN-SEP

  12. Homogeneity analysis 5 – station 050 -2(ref.series for making adjustm. – for this presentation only) 1975 JAN FEB MAR APR 1941 1985 1951 MAY JUN JUL AUG SEP OCT NOV DEC Notice scale for AUG

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