Homogeneity is important when analyzing climatic long-term time series. This is to ensure that the variability in the time series is not affected by changes such as station relocations, instrumentation changes and changes in the surroundings. The subject of this study is a long-term temperature series from the Norwegian University of Life Sciences at Ås in Southern Norway, located in a rural area about 30 km south of Oslo. Different methods for calculation of monthly mean temperature were studied and new monthly means were calculated before the homogeneity testing was performed. The statistical method used for the testing was the Standard Normal Homogeneity Test (SNHT) by Hans Alexandersson. Five breaks caused by relocations and changes in instrumentation were identified. The seasonal adjustments of the breaks lay between –0.4°C and +0.5°C. Comparison with two other homogenized temperature series in the Oslo fjord region showed similar linear trends, which suggests that the long-term linear temperature trends in the Oslo fjord region are not much affected by spatial climate variation.


homogenization; monthly temperature mean; formula for monthly mean temperature; rural temperature data; long-term climate data; temperature trend; AnClim

Full Text:



ALEXANDERSSON H., 1986, A homogeneity test applied to precipitation data, Int. J. Climatol., 6, 661–675.

ALEXANDERSSON H., 1995, Homogeneity testing, multiple breaks and trends. Proceedings of the Sixth International Meeting on Statistical Climatology, Galway, Ireland, 439–441.

ALEXANDERSSON H., MOBERG A., 1997, Homogenization of Swedish temperature data. Part 1: A homogeneity test for linear trends, Int. J. Climatol., 17, 25–34.

ANDRESEN L., 2011, Homogenization of monthly long-term temperature series of mainland Norway, note No. 02/2011, Norwegian Meteorological Institute.

BIRKELAND B.J., 1935, Mittel und Extreme der Lufttemperatur, Geofysiske Publikasjoner, XIV, No. 1, 153 pp.

DOMONKOS P., 2011, Adapted Caussinis-Mestre Algorithm for Networks of Temperature series (ACMANT), Int. J. Geosci., 2, 293–309.

DOMONKOS P., 2013, Measuring performances of homogenization methods, Időjárás-Quarterly Journal of the Hungarian Meteorological Service, 117, 1, 91–112.

DUCRÉ-ROBITAILLE J., VINCENT L.A., BOULET G., 2003, Comparison of techniques for detection of discontinuities in temperature series, Int. J. Climatol., 23, 1087–1101.

GUIJARRO J., A., 2013, Climatological series shift test comparison on running windows. Időjárás-Quarterly Journal of the Hungarian Meteorological Service, 117, No.1, 35–45.

HEINO R., 1994, Climate in Finland during the period of meteorological observations, Finnish Meteorological Institute Contributions, No. 12, 209 pp.

HØGÅSEN S., 1993, Mean temperature in meteorology, DNMI report No. 40/93 Klima, Norwegian Meteorological Institute.

KÖPPEN W., 1888, Über die Ableitung wahrer Tagesmittel aus den Beobachtungen um 8h a.m., 2h p.m. und 8h p.m., Annalen der Hydrographie un Maritimen Meteorologie, 16, 341–354.

MESTRE O., DOMONKOS P., PICARD F., AUER I., ROBIN S., LEBARBIER E., BÖHM R., AGUILAR E., GUIJARRO J., VERTACHNIK G., KLANCAR M., DUBUISSON B., STEPANEK P., 2013, HOMER: a homogenization software-methods and applications, Időjárás-Quarterly Journal of the Hungarian Meteorological Service, 117, 1, 47–67.

MOBERG A., ALEXANDERSSON H., 1997, Homogenization of Swedish temperature data. Part II: Homogenized gridded air temperature compared with a subset of global gridded air temperature since 1861, Int. J. Climatol., 17, 35–54.

NORDLI Ø., 1997, Homogenitetstesting av norske temperaturseriar II [Homogenity testing of Norwegian temperature series II], DNMI report No. 29/97 Klima, Norwegian Meteorological Institute.

NORDLI Ø., TVEITO O., E., 2008, Calculation of monthly mean temperature by Köppens formula in the Norwegian station network, report No. 18/2008, Norwegian Meteorological Institute.

PETERSON T., C., EASTERLING D., R., KARL T.,R., GROISMAN P., NICHOLLS N., PLUMMER N., TOROK S., AUER I., BOEHM R., GULLET D., VINCENT L., HEINO R., TUOMENVIRTA H., MESTRE O., SZENTIMREY T., SALINGER J., FØRLAND E., J., HANSSEN-BAUER I., ALEXANDERSSON H., JONES P., PARKER D., 1998, Homogeneity adjustments of in situ atmospheric climate data: A review, Int. J. Climatol., 18, 1493–1517.

ŠTĚPÁNEK P., 2008a, AnClim-software for time series analysis: Dept. of Geography, Fac. of Natural Sciences, MU, Brno, Czech Republic, 1.47 MB.

ŠTĚPÁNEK P., 2008b, ProClimDB-software for processing climatological datasets, CHMI, regional office Brno, Czech Republic.

SZENTIMREY T., 2007, Manual of homogenization software MASH v3.02, Hungarian Meteorological Service.

TUOMENVIRTA H., 2002, Homogeneity testing and adjustment of climatic time series in Finland, Geophysica, 38 (1–2), 15–41.

TUOMENVIRTA H., 2001, Homogeneity adjustments of temperature and precipitation series-Finnish and Nordic data, Int. J. Climatol., 21, 495–506.

ISSN 2080-7686 (print)
ISSN 2300-8490 (online)



Partnerzy platformy czasopism