The relationship between four monthly Northern Hemisphere (NH) atmospheric circulation indices, defined as Varimax rotated principal components (VRPC) of monthly average 500 hPa surface geopotential ...heights for the NH, and the Danube River Basin (DRB) monthly precipitation amount anomalies for 26 weather stations and average monthly discharge anomalies for 10 hydrological stations on a major waterway of the DRB was analysed for the period 1961–2010. A weak average correlation was established between the Northern Atlantic Oscillation (NAO), the Eastern Atlantic (EA) and the Scandinavian (SCA) index and the monthly precipitation/discharge anomalies for the DRB, while a more significant average correlation was established for the Eastern Atlantic/Western Russia (EA/WR) index, especially in the winter season. A type of DRB precipitation index, based on principal component analysis (PCA), was used for the classification of DRB monthly precipitation totals and average monthly discharge anomalies into similar space patterns. A mutual relationship between these patterns and the European-Northern Atlantic sea-level composite maps was achieved. The clustering indicated the relationship between synoptic scale spatial features in sea-level pressure anomalies for the European-Northern Atlantic region and the DRB monthly precipitation and discharge anomaly spatial patterns. A statistic of typical pattern frequency of precipitation/discharge anomalies was obtained and discussed.
The study addresses homogeneity testing of annual discharge time series for eight hydrological stations and five annual climate time series for one weather station in the Kupa River Basin, between ...Slovenia and Croatia, and global annual average surface temperature time series for the period 1961-2010. The standard normal homogeneity test (SNHT) was used to detect both abrupt and gradual linear trend homogeneity breaks. The results reveal natural change points at the beginning of the 1980s. Absolute homogeneity testing of average annual weather station-level air pressure, annual precipitation, differences between precipitation totals and potential evapotranspiration and surface runoff from the independent observation time series confirmed an abrupt shift, also at the beginning of the 1980s. The trend of local air temperature for 1985-2000, which partly coincides with global surface temperature trend for 1974-2005, strengthened the river discharge regime shift since the beginning of the 1980s. These results could improve climate variation monitoring and estimation of the impact of climate variation on the environment in the area. Generally, an indication of climate regime change points and an assessment of their duration could provide significant benefits for the society.
Recent global warming and more frequent droughts are causing significant damage to maize production. A reliable estimate of drought intensity and duration is essential for testing maize hybrids to ...drought tolerance. For this purpose, the self-calibrating 10-day palmer drought severity index (scPDSI) and standardized precipitation index (SPI) for 1, 2, 3, 6, 9, 18, 27, and 36 10-day scales were used to estimate the effects of drought on grain yield of 32 maize hybrids evaluated in 2017 and 2018 at eight experimental locations in the Pannonian part of Croatia. Time series of observed 10-day mean air temperature, relative humidity, and precipitation totals for a set of “reference” weather stations of the croatian meteorological and hydrological service (DHMZ) for the period 1981–2018 were used to calculate the scPDSI and SPI indices. According to the 10-day scPDSI and SPI for different time scales, 2018 proved to be a “normal year,” while 2017 experienced a “mild to moderate drought,” which resulted in a 13% reduction in maize grain yield at eight experimental locations compared to 2018. The correlation between grain yield and drought indices for summer months was the highest for the 10-day scPDSI. To some extent, correlations between summer months’ SPI for the 3 10-day time scale and maize grain yield were comparable to the corresponding correlations for the 10-day scPDSI. However, for other SPI time scales considered, the corresponding correlations were weaker and less informative. The dependence of grain yield on scPDSI values was not the same for all hybrids, indicating their different tolerance to drought. The reduction in grain yield due to drought was primarily caused by insufficient grain filling (lower 1000-grain weight) and, to some extent, by a reduction in the number of grains. In this study, application of 10-day scPDSI data proved to be more relevant in detecting effects of drought on agronomic traits than application of SPI data for the most time scales.
A historical review of extreme air temperature analysis in Croatia is presented. Two capital works on the subject were published in the 1970s by the Croatian Meteorological and Hydrological Service ...(DHMZ) and Faculty of Science University of Zagreb (PMF-Zagreb), respectively. The first is a monography on extreme value theory or extreme value analysis (EVA) with an application on more than a century-long time series of annual minima air temperature for Zagreb Grič weather station (Croatia) for the period 1862–1969. It is just a case study, with a lot of instructions regarding how to estimate the generalized extreme value (GEV) distribution parameters. The second is a master’s thesis with an application of the EVA on maxima air temperature time series for 41 weather stations from Croatia for the period 1950–1969. The shortness of the time series of the presented data caused instability in the estimation of GEV distribution parameters in transition areas from continental to maritime climate, but in general, the results are acceptable after a reduction of the 1950–1969 time series data on a ‘normal climate period’ 1910–1969. Both works were pioneering for that time in the South-Eastern Europe scale. A routine application of GEV distribution on the extreme air temperature (both minimum and maximum) for ten representative weather stations from Croatia is represented in Climate atlas of Croatia for the period 1961–1990, published by DHMZ in 2008. Theoretically estimated results fit well with empirical data. A review of long-term “warm” and “cold” indices of extreme air temperature for 41 weather stations from Croatia for the period 1951–2010 is represented in the Sixth National Communication Report of Croatia under the UNFCCC published by the Ministry for Environment and Nature Protection of Croatia (MZOIP) in 2014, showing a positive trend of “warm” and a negative trend of “cold” indices during the period 1951–2010 which tackled the non-stationarity of extreme air temperature time series. That topic of non-stationarity is more extensively considered using the results of a series of scientific papers published in the international journals which conducted a study of extreme air temperature of the wider Western Europe territory, including Croatia and other countries close to Croatia. Some authors of these papers stated that the GEV distribution parameters have to be considered as a function of time rather than fixed in time using covariates like North Atlantic Oscillation (NAO), coherent atmospheric blocking regions, linear trends in data caused by global warming and others covariates. The EVA results, connected with the global climate warming, could contribute to the national Natural Disaster Risk Reduction (NDRR) efforts.
The relatively new sea level satellite altimetry and secular coastal tide gauge data made the reconstruction of sea levels on regional and global scales possible about one century back. Due to better ...estimations of the Earth’s crustal, glacial, tectonic, and other possible motion biases in tide gauge data, some additional improvements can be expected in sea level reconstructions, analysis, and predictions. A more detailed review of published sea level-related results was conducted for the Eastern Adriatic coast, including the operation of the tide gauge network and data processing, crustal movement estimations, and the establishment of a new reference height system in Croatia, based on five tide gauge sea level data. It was shown that sea level variation and trend-related indicators are spatially homogeneous, especially on a sub-Adriatic scale. The regional Adriatic Sea mean sea level rise rate of +2.6 mm/year for the satellite altimetry era (1993–2019) is less than the global mean sea level (GMSL) rise rate of +3.3 mm/year for the period of 1993–2022. Several empirical methods for GMSL projections and expected IPCC (Intergovernmental Panel on Climate Change) assessments until the end of the 21st century are considered.
The Standardized Precipitation Index (SPI) for different time scales of
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months and the monthly Palmer Drought Severity Index (PDSI) were calculated for the ...Zagreb-Grič Observatory, located in North-Western Croatia, for the period 1862–2012. The PDSI exhibits a stronger long-term negative trend than the SPI due to the influence of the global warming, which corresponds with the global scale results published in the 4th IPCC (Intergovernmental Panel on Climate Change) report. The SPI for a 9-month scale was compared with the PDSI for a monthly scale because the correlation between them is the highest in comparison with other SPI time scales. The Chapman percentile classification regarding dryness/wetness severity was used instead of the “originally” proposed classes. Thirty-year moving averages indicate that long-term variation in dryness/wetness severity is more clearly emphasised for the PDSI than for the SPI, showing the last 30-year period to be the driest on record. Autoregressive function analysis indicates that the SPI for a 1-month scale has serialy independent values, while the SPI for the 9-month scale and the monthly PDSI are close to a Markov process. A significant correlation was established between the SPI and PDSI indices and crop damages in Croatia.
U radu se opisuje povijesni razvoj korištenja snage vjetra za plovidbu pomoću jedrenjaka, pumpanje vode i mljevenje žitarica, od antičkih vremena do danas. Tek je u drugoj polovici 19. stoljeća ...sagrađen određeni broj vjetroelektrana u SAD i sjevernoj Europi koje su služile za rasvjetu, no ubrzo su prestale s radom. Poslije naftne krize 1970-ih u SAD započinje izgradnja vjetroelekrana, osobito u Kaliforniji, a zatim je težište te gradnje prešlo u sjevernu i zapadnu Europu, 1990-ih. U Hrvatskoj taj proces intezivnije započinje 2007. godine poslije uređenja odgovarajuće zakonske regulative te usklađivanja propisa s Europskom unijom pa se u današnje vrijeme oko 10 % energije u Hrvatskoj proizvodi korištenjem obnovljivih izvora, većinom od vjetra. Prikazan je postupak procjene energije vjetra na osnovi raspoloživih opažanja vjetra na klimatološkoj postaji Imotski za razdoblje 1996∑2015. Ekstrapolirane su brzine vjetra s referentne razine 10 m na 50 m i 100 m visine korištenjem logaritamskog zakona promjene vjetra visinom te visine hrapavosti 0.4 m za niske objekte u okolišu meteorološke postaje Imotski. Procjena snage vjetra na temelju raspoloživih i izračunatih podataka smatra se preliminarnom procjenom te su raspoloživi rezultati samo orijentacijskoga tipa. Rezultati sugeriraju da postoji potreba za dodatnim mjerenjima u trajanju najmanje dvije godine na visinama između 10 m i 100 m na mikrolokaciji potencijalne vjetroelektrane. Osobito je naglašena komplementarnost upotrebe srednjeg godišnjeg hoda te međugodišnja promjena brzine vjetra za planiranje gospodarenja potencijalnim elektranama na području klimatološke postaje Imotski.
We analyze century‐long daily temperature and precipitation records for stations in Europe west of 60°E. A set of climatic indices derived from the daily series, mainly focusing on extremes, is ...defined. Linear trends in these indices are assessed over the period 1901–2000. Average trends, for 75 stations mostly representing Europe west of 20°E, show a warming for all temperature indices. Winter has, on average, warmed more (∼1.0°C/100 yr) than summer (∼0.8°C), both for daily maximum (TX) and minimum (TN) temperatures. Overall, the warming of TX in winter was stronger in the warm tail than in the cold tail (1.6 and 1.5°C for 98th and 95th, but ∼1.0°C for 2nd, 5th and 10th percentiles). There are, however, large regional differences in temperature trend patterns. For summer, there is a tendency for stronger warming, both for TX and TN, in the warm than in the cold tail only in parts of central Europe. Winter precipitation totals, averaged over 121 European stations north of 40°N, have increased significantly by ∼12% per 100 years. Trends in 90th, 95th and 98th percentiles of daily winter precipitation have been similar. No overall long‐term trend occurred in summer precipitation totals, but there is an overall weak (statistically insignificant and regionally dependent) tendency for summer precipitation to have become slightly more intense but less common. Data inhomogeneities and relative sparseness of station density in many parts of Europe preclude more robust conclusions. It is of importance that new methods are developed for homogenizing daily data.
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