G e o f i z i k a

Drought monitoring in Croatia using the standardized precipitation-evapotranspiration index

2024-06-13T09:50:36+02:00

Several periods of drought in the 21st century have severely affected large parts of Europe and caused considerable economic losses, particularly in the agricultural and energy sectors. While rainfall deficits are one of the main causes of droughts, high temperatures in the summer months exacerbate their development, which can have devastating consequences. This was the case in 2022, when long dry spells were accompanied by several heat waves. In this study, climatological drought monitoring using the Standardized Precipitation Evapotranspiration Index (SPEI) is analyzed with the primary goal of finding the best theoretical distribution for adjusting the water balance (defined as the difference between precipitation and potential evapotranspiration) in Croatia before the index is officially introduced into the operational drought monitoring. Although the SPEI is widely used for drought monitoring, the underlying theoretical distribution of the water balance may differ between regions. The study is based on monthly precipitation amounts and monthly mean values of daily minimum and maximum temperatures observed at 31 main meteorological stations for the period 1961–2022. The analysis is carried out for different time scales, ranging from 1 to 24 months. Among the five distributions considered, a generalized logistic distribution with three parameters (GLO) proves to be the most appropriate. There is general agreement between SPEI and SPI time series, both in terms of sign and intensity. However, in periods with a light to moderate lack of precipitation and high air temperatures, a tendency towards higher drought intensity prevails in the SPEI. A comparative analysis of the 2022 drought in Croatia confirmed the ability of the SPEI to detect a drought earlier than the SPI, which also suggests that a larger area of the country was affected by the drought due to consistent air temperature excesses.

Night sky brightness trends above Zagreb, 2012–2022

2024-01-25T10:48:50+01:00

The night sky brightness at the RGN site (near the centre of Zagreb, Croatia) was monitored from January 2012 to August 2022. The first data set, covering the period 2012 to 2017, has already been analysed and the conclusions were published in Andreić (2018). The main conclusions are repeated here for comparison and completeness. The results of the analysis of the second dataset, covering the period from January 2018 to July 2022, are reported here.

The first data analysis showed that the average night sky brightness did not change significantly from 2012 to 2017, excluding differences due to annual variations in meteorological parameters. The second data set (2018 to 2022) showed a slight decrease in night sky brightness compared to the first data set. The difference is small, about 0.2 mag/arcsec² (mean values). In the second data set, there is a trend toward darker nights in later years that began three or four years ago (around 2019 or 2020). It is attributed to the modernisation of the public lighting network, where old, often very poor lighting fixtures are slowly being replaced by modern LED lighting fixtures, and to the effects of climatic changes leading to warmer winters with more clear nights.

Results of the magnetometer inter-comparisons during the 2nd Cycle of Geomagnetic Information Renewal in the Republic of Croatia

2024-06-19T12:41:02+02:00

Between 2017 and 2021, the 2nd Geomagnetic Information Renewal Cycle was carried out on the Croatian Geomagnetic Repeat Stations Network (CGRSN). On several occasions, before and after the survey at CGRSN, the magnetometers used in the survey were tested at the Lonjsko Polje Geomagnetic Observatory (LON). This paper presents the methods and results of these tests. The results verified the correctness of the used magnetometers and confirmed that their absolute accuracy is within the targeted measurement accuracy at the secular point. Despite the favourable results, a detail analysis revealed the presence of a small magnetic offset. This offset was introduced during the comparison process and did not affect the CGRSN measurements results in any way. In this paper, we share our experience which could be instructive for other observers performing similar work. Further testing is needed to determine the exact direction and magnitude of this systematic offset.

Quo vadis scientia? The tales of recent Croatian publications in geodesy and geophysics

2024-04-04T10:53:15+02:00

Research publications are a key indicator in evaluations of both the careers of scientists and the performance of research institutions and science systems. However, unprecedented changes in publishing have been made in recent decades following the development of solutions that can be helpful in managing publications and the conjoined peer-review process. In that spirit, we performed a comparative study of research articles reported by the Croatian Committee of Geodesy and Geophysics between two 4-year periods, 2019-2022 and 2015-2018, focusing in particular on the changes in journals and publishers between these periods. Apparently, there is a dramatic change in articles between these two periods, directed toward publishers that have much shorter evaluation times, such as MDPI and Frontiers. In almost all subcategories, the percentage of articles in the MDPI increased several times, reaching approximately 65% in hydrology and physical limnology and 30% in geodesy. We argue that these changes are worsening the reliability of science, driven by the national rules that favor the ‘publish or perish’ principle over the quality of research. Furthermore, we propose a way to cope with this problem at the national level, which should include a transition toward reliable publishers and peer-review assessments implemented during research evaluations.