Homogenized and gridded mean temperature data series in Hungary from the mid-19th century

The longest period of meteorological measurements in Hungary is available for the temperature records. A substantial expansion of the number of data series used to homogenize temperatures is currently under way, extending back to the second half of the 19th century. The main motivation of the study is the fact that a long-term database based on high-quality measurements is essential to better understand the regional climate and its changes.

To improve the understanding of climate and its changes requires temporally and spatially representative climate databases. However, measurement conditions change frequently: the relocation of stations, instrument changes, changes in measurement time, changes in environmental conditions can all cause inhomogeneities in the data series, and therefore homogenization is needed.

For homogenization of data series, quality control and filling in the missing values the MASH (Multiple Analysis of Series for Homogenization) procedure (MASHv3.03 software) is used at the Climate Research Department of the HungaroMet Hungarian Meteorological Service. Nowadays, temperature is measured in many more places than, for example, 100-150 years ago, so the homogenization should consist of several steps (i.e. 3 or more MASH systems). For example, we currently use temperature data from 34 stations from 1901 and 55 stations from 1951. These station networks are further extended. Inhomogeneities are estimated using monthly data series. Monthly, seasonal and annual inhomogeneities are harmonized in all MASH systems. Then, we create temporally representative data series using the MASH homogenization procedure.

However, weather stations are not evenly distributed, the station network consists of both densely and sparsely covered subregions. In order to estimate the values of meteorological variables at points where no measurements are available, a spatial interpolation method must be used. Our gridded climate datasets are generated using the MISH (Meteorological Interpolation based on Surface Homogenized Data Basis) method (MISHv1.03 software). The use of the MISH interpolation results in a spatially representative climate database.

In this presentation, the new mean temperature station systems used for homogenization are described together with the most important verification statistics of the homogenization of mean temperature data series, and finally, the gridded spatial means (national averages for Hungary) are analyzed from the mid-19th century to the present.

 

Acknowledgements:

The research presented was carried out within the framework of the Széchenyi Plan Plus program with the support RRF 2.3.1 21 2022 00008 project.