AUTOKORELACIJSKA I KROSKORELACIJSKA ANALIZA PROTOKA UZ UŠĆE KUPE U SAVU

In this paper, an autocorrelation and cross-correlation analysis of the flow of the Kupa and Sava rivers was performed. The analysis was performed at hydrological stations close to the confluence of these two rivers near the city of Sisak, based on data of mean daily flows and daily precipitation. The analysed time period is from 2008 to 2017, with the series being divided into two parts of five years each, from 2008 to 2012 and 2013 to 2017. Daily flow data were measured at the hydrological stations Farkašić on the Kupa River and Crnac on the Sava River, and data on precipitation at the main meteorological station and the automatic meteorological station Sisak. The maximum value of the cross-correlation function between the hydrological stations at the Kupa and Sava rivers is very high, but at a time lag of zero days. The value of the cross-correlation function remains high, up to 0.6 and up to a 4 day lag. The cross-correlation function between precipitation and hydrological data has a very low maximum value.U ovome radu provedena je autokorelacijska i kroskorelacijska analiza toka rijeka Kupe i Save na hidrološkim postajama u blizini ušća Kupe i Save nedaleko od grada Siska, na temelju podataka o srednjim dnevnim protocima i dnevnim količinama oborina. Analizirano je vremensko razdoblje od 2008. do 2017. godine, s tim da su vremenski nizovi podijeljeni u dva dijela po pet godina, od 2008. do 2012. i od 2013. do 2017. Podatci dnevnoga protoka mjereni su na hidrološkim postajama Farkašić na rijeci Kupi i Crnac na rijeci Savi te su uzeti podatci o oborinama na glavnoj meteorološkoj postaji i automatskoj meteorološkoj postaji Sisak. Maksimalna vrijednost kroskorelacijske funkcije između hidroloških postaja na Kupi i Savi vrlo je visoka, ali u vremenskome kašnjenju od nula dana. Vrijednost kroskorelacijske funkcije ostaje visoka do 0,6 i do 4 dana zakašnjenja. Kroskorelacijska funkcija između oborina i hidroloških podataka ima vrlo nisku maksimalnu vrijednost

USPOREDBA SVJETLINE NOĆNOGA NEBA IZNAD ZAGREBA I IZNAD BLISKE RURALNE LOKACIJE ZA RAZDOBLJE OD 2014. DO 2017.

The results of monitoring light pollution near the center of Zagreb at the Faculty of Mining, Geology and Petroleum Engineering (RGN) for the period 2012 - 2017 were presented in a recent article (Andreić, 2018). The question that remained unanswered is how the night sky brightness behaves in the suburbs of Zagreb and in the nearby rural area. This article attempts to give some answers to this question by analyzing data gathered at the rural site of Merenje, located north of Zagreb. The main conclusion drawn is that the night sky brightness at both sites follows very similar patterns for clear sky conditions and is often similar for cloudy conditions, too. For both sites, no significant increase in zenithal night sky brightness was found in the observed period of 2014 - 2017. Thus, at least for the areas north of Zagreb that are in the shadow of Medvednica Mountain, the contribution of the light pollution from Zagreb and its growing outskirts remains unaltered. The main difference is in the level of the night sky brightness, the average for the RGN site being 16.9 mag/ arcsec2 and 18.9 mag/arcsec2 for the Merenje site. Additionally, the cloudy conditions enhance the light pollution of Zagreb a lot more, the difference being about 3.2 mag/arcsec2 for RGN, in contrast to 1.9 mag/arcsec2 for the Merenje site. No measurements exist for areas to the south, so no conclusions can be made for the situation there. Last, but not least, it was found that in cloudy conditions, the stronger light pollution of Zagreb is proportionally more enhanced by the clouds/fog than the smaller levels of light pollution at the Merenje site.Rezultati praćenja svjetlosnoga onečišćenja u blizini središta Zagreba za razdoblje od 2012. do 2017. prikazani su u nedavnome članku (Andreić, 2018). Ostalo je neodgovoreno kako se ponaša svjetlina noćnoga neba u predgrađima Zagreba i u obližnjemu ruralnom području. Ovaj članak pokušava dati odgovor na to pitanje analizom podataka prikupljenih na jednome ruralnom lokalitetu sjeverno od Zagreba. Glavni je zaključak ovoga rada da svjetlina noćnoga neba na obama mjestima ima vrlo slične obrasce u uvjetima vedra neba, a često je slična i pri oblačnome vremenu. Za oba mjesta nije zabilježeno znatno povećanje zenitne svjetline noćnoga neba u razmatranome razdoblju od 2014. do 2017. Jedina razlika postoji u jačini svjetline noćnoga neba, za koju je srednja vrijednost za RGN lokaciju 16,9 mag/arcsec2, odnosno 18,9 mag/arcsec2 za lokaciju Merenje. Tako za područja sjeverno od Zagreba koja su u sjeni planine Medvednice nema znatnoga doprinosa svjetlosnoga onečišćenja iz Zagreba. Ne postoje mjerenja za područja južno od Zagreba, tako da se ne može donijeti zaključak o tamošnjoj situaciji. Na kraju je ustanovljeno da je u oblačnim uvjetima jače svjetlosno onečišćenje Zagreba proporcionalno pojačano oblacima/maglom od manjih razina svjetlosnoga onečišćenja na mjestu Merenje

Regional hydrological analysis of the Kupa karstic basin : doctoral thesis

Regionalna hidrološka analiza provedena je na osnovi podataka s hidrometrijskih profila koji se nalaze na području krškog sliva Kupe. Obrađeni su podaci s 32 hidrološka profila na 20 vodotoka do profila: Kamanje na Kupi, Stative Donje na Dobri, Mrzlo polje na Mrežnici i Veljun na Korani, a ukupna površina obrađenih slivova iznosi oko 5.450 km2. Obrađeni hidrološki podaci su srednji dnevni protoci te srednji, maksimalni i minimalni godišnji protoci. Osim hidroloških podataka, obrađeni su i podaci o dnevnim oborinama prikupljenim na klimatološkim stanicama Parg, Ogulin i Karlovac. Razdoblje obrade je (1981.-2012.), a dobiveni rezultati su uspoređeni s rezultatima ranijih istraživanja u kojima je analizirano razdoblje (1951.-1980). Usporedba trendova srednjih godišnjih protoka, kojom se ujedno opravdava usvojeno razdoblje obrade, pokazala je da je u ranijem razdoblju (1951.-1980.) osam nizova imalo opadajući trend, a 11 nizova rastući, dok je u razdoblju ove obrade (1981.-2012.) 20 nizova imalo opadajući trend a 12 nizova rastući trend. Maksimalni godišnji protoci su u ranijem razdoblju imali sedam nizova opadajućeg trenda a 12 nizova rastućeg trenda, dok je u razdoblju ove obrade 27 nizova imalo opadajući trend a pet nizova rastući trend. Minimalni godišnji protoci u ranijem razdoblju obrade su imali sedam nizova opadajućeg trenda i 12 nizova rastućeg trenda, a u razdoblju ove obrade je 15 nizova imalo opadajući trend, a 17 nizova rastući trend. Analiza homogenosti srednjih, maksimalnih i minimalnih godišnjih protoka razdoblja obrade (1981.-2012.) u odnosu na razdoblje (1951.-1980.) pokazala je da je najviše nehomogenih nizova kod srednjih godišnjih protoka dok je kod maksimalnih i minimalnih godišnjih protoka većina nizova homogena. Nehomogenost nizova srednjih godišnjih protoka potvrđuje pretpostavku o sušnijem razdoblju koje je nastupilo početkom 80-ih godina prošlog stoljeća, i traje sve do danas. U ovoj regionalnoj hidrološkoj analizi izvedeno je 10 dvoparametarskih zakonitosti veza karakterističnih parametara srednjih godišnjih protoka, 72 dvoparametarskih zakonitosti veza karakterističnih parametara maksimalnih godišnjih protoka, zajedno s parametrima maksimalnih protoka i volumena različitih povratnih razdoblja i 10 dvoparametarskih zakonitosti veza karakterističnih parametara minimalnih godišnjih protoka. Definirani su i teorijski hidrogrami 10-, 100- i 1000-godišnjeg povratnog razdoblja duž toka Kupe. Izdvojene su zakonitosti veza koje se mogu preporučiti za primjenu u praksi. Analiza višeparametarskih zakonitosti veza dala je dvije moguće troparametarske zakonitosti, međutim one nisu preporučljive za upotrebu zbog vrlo širokih intervala pouzdanosti, iako imaju visoke vrijednosti koeficijenta korelacije. Spektralna analiza protoka i oborina pokazala je da su se u razdoblju istraživanja (1981.-2012.) ekstremi protoka i oborina pojačali i više istaknuli, ali da se ukupna količina oborine i protoka smanjila u odnosu na ranije razdoblje (1951.-1980.). Ključne riječi: regionalna hidrološka analiza, spektralna analiza, protok, oborina, krš, sliv Kupe.Regional hydrological analysis was conducted using data from the catchments located in the area of karst basin of the Kupa river. The study included data from 32 hydrological profiles on 20 watercourses down to Kamanje on Kupa, Stative Donje on Dobra, Mrzlo polje on Mrežnica and Veljun on Korana profiles. Catchment area to specified profiles is approximately 5450 km2. The processed hydrological data are the average daily flows and the average, maximum and minimum annual flows. In addition to hydrological data, the daily rainfall data collected on climatological stations Parg, Ogulin and Karlovac were processed. The period of analysis is from 1981 to 2012, and the results were compared with the results of previous studies that analyzed the period from 1951 to 1980. The comparison of trends in mean annual flows, which also justifies the chosen period of analysis, has shown that in the earlier period from 1951 to 1980 eight time-sets showed a declining trend, and 11 time-sets showed growing trend, while in the analyzed period from 1981 to 2012, 20 time-sets showed a declining trend, and 12 time-sets showed growing trend. The maximum annual flows in the earlier period consisted of seven time-sets showing a declining trend and 12 time-sets showing the growing trend, while in the period of this analysis 27 time-sets showed a declining trend and five time-sets showed a growing trend. The minimum annual flows in the earlier period analysis consisted of seven time-sets showing a declining trend and 12 time-sets showing the growing trend, and in the period of this analysis, 15 time-sets have shown a declining trend, and 17 time-sets have shown a growing trend. The analysis of homogeneity of average, maximum and minimum annual flow for the 1981 to 2012 period in relation to the 1951 to 1980 period, shows that majority of non-homogeneous time-sets were present with average annual flows, while the majority of time-sets of maximum and minimum annual flows were homogeneous. The homogeneity of average annual flows confirms the assumption of a drier period, which occurred in the early 1980s and continues to this day. In this regional hydrological analysis, the following was conducted: 10 two-parameter models’ relationships of the average annual flow characteristic parameters, 72 two-parameter models’ relationships of the maximum annual flow characteristic parameters, together with the parameters of the maximum flow rate and the volume of different return periods and 10 two-parameter models’ relationships of the minimum annual flow characteristic parameters. Theoretical hydrographs of 10-, 100- and 1000-year return period along the Kupa river flow were defined. Two-parameters’ models that can be used in practice were selected. Although the analysis of multi-parameter relationships produced two possible three-parameter relationships, they are not recommended for use because of the very wide confidence interval, regardless of the correlation coefficient high value. Spectral analysis of the flows and precipitation shows that during the period of analysis from 1981 to 2012, extremes of flows and precipitation were strengthened and more pointed out, but the total amount of precipitation and flows declined, compared to the previous period from 1951 to 1980

Regional hydrological analysis of the Kupa karstic basin : doctoral thesis

Regionalna hidrološka analiza provedena je na osnovi podataka s hidrometrijskih profila koji se nalaze na području krškog sliva Kupe. Obrađeni su podaci s 32 hidrološka profila na 20 vodotoka do profila: Kamanje na Kupi, Stative Donje na Dobri, Mrzlo polje na Mrežnici i Veljun na Korani, a ukupna površina obrađenih slivova iznosi oko 5.450 km2. Obrađeni hidrološki podaci su srednji dnevni protoci te srednji, maksimalni i minimalni godišnji protoci. Osim hidroloških podataka, obrađeni su i podaci o dnevnim oborinama prikupljenim na klimatološkim stanicama Parg, Ogulin i Karlovac. Razdoblje obrade je (1981.-2012.), a dobiveni rezultati su uspoređeni s rezultatima ranijih istraživanja u kojima je analizirano razdoblje (1951.-1980). Usporedba trendova srednjih godišnjih protoka, kojom se ujedno opravdava usvojeno razdoblje obrade, pokazala je da je u ranijem razdoblju (1951.-1980.) osam nizova imalo opadajući trend, a 11 nizova rastući, dok je u razdoblju ove obrade (1981.-2012.) 20 nizova imalo opadajući trend a 12 nizova rastući trend. Maksimalni godišnji protoci su u ranijem razdoblju imali sedam nizova opadajućeg trenda a 12 nizova rastućeg trenda, dok je u razdoblju ove obrade 27 nizova imalo opadajući trend a pet nizova rastući trend. Minimalni godišnji protoci u ranijem razdoblju obrade su imali sedam nizova opadajućeg trenda i 12 nizova rastućeg trenda, a u razdoblju ove obrade je 15 nizova imalo opadajući trend, a 17 nizova rastući trend. Analiza homogenosti srednjih, maksimalnih i minimalnih godišnjih protoka razdoblja obrade (1981.-2012.) u odnosu na razdoblje (1951.-1980.) pokazala je da je najviše nehomogenih nizova kod srednjih godišnjih protoka dok je kod maksimalnih i minimalnih godišnjih protoka većina nizova homogena. Nehomogenost nizova srednjih godišnjih protoka potvrđuje pretpostavku o sušnijem razdoblju koje je nastupilo početkom 80-ih godina prošlog stoljeća, i traje sve do danas. U ovoj regionalnoj hidrološkoj analizi izvedeno je 10 dvoparametarskih zakonitosti veza karakterističnih parametara srednjih godišnjih protoka, 72 dvoparametarskih zakonitosti veza karakterističnih parametara maksimalnih godišnjih protoka, zajedno s parametrima maksimalnih protoka i volumena različitih povratnih razdoblja i 10 dvoparametarskih zakonitosti veza karakterističnih parametara minimalnih godišnjih protoka. Definirani su i teorijski hidrogrami 10-, 100- i 1000-godišnjeg povratnog razdoblja duž toka Kupe. Izdvojene su zakonitosti veza koje se mogu preporučiti za primjenu u praksi. Analiza višeparametarskih zakonitosti veza dala je dvije moguće troparametarske zakonitosti, međutim one nisu preporučljive za upotrebu zbog vrlo širokih intervala pouzdanosti, iako imaju visoke vrijednosti koeficijenta korelacije. Spektralna analiza protoka i oborina pokazala je da su se u razdoblju istraživanja (1981.-2012.) ekstremi protoka i oborina pojačali i više istaknuli, ali da se ukupna količina oborine i protoka smanjila u odnosu na ranije razdoblje (1951.-1980.). Ključne riječi: regionalna hidrološka analiza, spektralna analiza, protok, oborina, krš, sliv Kupe.Regional hydrological analysis was conducted using data from the catchments located in the area of karst basin of the Kupa river. The study included data from 32 hydrological profiles on 20 watercourses down to Kamanje on Kupa, Stative Donje on Dobra, Mrzlo polje on Mrežnica and Veljun on Korana profiles. Catchment area to specified profiles is approximately 5450 km2. The processed hydrological data are the average daily flows and the average, maximum and minimum annual flows. In addition to hydrological data, the daily rainfall data collected on climatological stations Parg, Ogulin and Karlovac were processed. The period of analysis is from 1981 to 2012, and the results were compared with the results of previous studies that analyzed the period from 1951 to 1980. The comparison of trends in mean annual flows, which also justifies the chosen period of analysis, has shown that in the earlier period from 1951 to 1980 eight time-sets showed a declining trend, and 11 time-sets showed growing trend, while in the analyzed period from 1981 to 2012, 20 time-sets showed a declining trend, and 12 time-sets showed growing trend. The maximum annual flows in the earlier period consisted of seven time-sets showing a declining trend and 12 time-sets showing the growing trend, while in the period of this analysis 27 time-sets showed a declining trend and five time-sets showed a growing trend. The minimum annual flows in the earlier period analysis consisted of seven time-sets showing a declining trend and 12 time-sets showing the growing trend, and in the period of this analysis, 15 time-sets have shown a declining trend, and 17 time-sets have shown a growing trend. The analysis of homogeneity of average, maximum and minimum annual flow for the 1981 to 2012 period in relation to the 1951 to 1980 period, shows that majority of non-homogeneous time-sets were present with average annual flows, while the majority of time-sets of maximum and minimum annual flows were homogeneous. The homogeneity of average annual flows confirms the assumption of a drier period, which occurred in the early 1980s and continues to this day. In this regional hydrological analysis, the following was conducted: 10 two-parameter models’ relationships of the average annual flow characteristic parameters, 72 two-parameter models’ relationships of the maximum annual flow characteristic parameters, together with the parameters of the maximum flow rate and the volume of different return periods and 10 two-parameter models’ relationships of the minimum annual flow characteristic parameters. Theoretical hydrographs of 10-, 100- and 1000-year return period along the Kupa river flow were defined. Two-parameters’ models that can be used in practice were selected. Although the analysis of multi-parameter relationships produced two possible three-parameter relationships, they are not recommended for use because of the very wide confidence interval, regardless of the correlation coefficient high value. Spectral analysis of the flows and precipitation shows that during the period of analysis from 1981 to 2012, extremes of flows and precipitation were strengthened and more pointed out, but the total amount of precipitation and flows declined, compared to the previous period from 1951 to 1980

Regional hydrological analysis of the Kupa karstic basin : doctoral thesis

Regionalna hidrološka analiza provedena je na osnovi podataka s hidrometrijskih profila koji se nalaze na području krškog sliva Kupe. Obrađeni su podaci s 32 hidrološka profila na 20 vodotoka do profila: Kamanje na Kupi, Stative Donje na Dobri, Mrzlo polje na Mrežnici i Veljun na Korani, a ukupna površina obrađenih slivova iznosi oko 5.450 km2. Obrađeni hidrološki podaci su srednji dnevni protoci te srednji, maksimalni i minimalni godišnji protoci. Osim hidroloških podataka, obrađeni su i podaci o dnevnim oborinama prikupljenim na klimatološkim stanicama Parg, Ogulin i Karlovac. Razdoblje obrade je (1981.-2012.), a dobiveni rezultati su uspoređeni s rezultatima ranijih istraživanja u kojima je analizirano razdoblje (1951.-1980). Usporedba trendova srednjih godišnjih protoka, kojom se ujedno opravdava usvojeno razdoblje obrade, pokazala je da je u ranijem razdoblju (1951.-1980.) osam nizova imalo opadajući trend, a 11 nizova rastući, dok je u razdoblju ove obrade (1981.-2012.) 20 nizova imalo opadajući trend a 12 nizova rastući trend. Maksimalni godišnji protoci su u ranijem razdoblju imali sedam nizova opadajućeg trenda a 12 nizova rastućeg trenda, dok je u razdoblju ove obrade 27 nizova imalo opadajući trend a pet nizova rastući trend. Minimalni godišnji protoci u ranijem razdoblju obrade su imali sedam nizova opadajućeg trenda i 12 nizova rastućeg trenda, a u razdoblju ove obrade je 15 nizova imalo opadajući trend, a 17 nizova rastući trend. Analiza homogenosti srednjih, maksimalnih i minimalnih godišnjih protoka razdoblja obrade (1981.-2012.) u odnosu na razdoblje (1951.-1980.) pokazala je da je najviše nehomogenih nizova kod srednjih godišnjih protoka dok je kod maksimalnih i minimalnih godišnjih protoka većina nizova homogena. Nehomogenost nizova srednjih godišnjih protoka potvrđuje pretpostavku o sušnijem razdoblju koje je nastupilo početkom 80-ih godina prošlog stoljeća, i traje sve do danas. U ovoj regionalnoj hidrološkoj analizi izvedeno je 10 dvoparametarskih zakonitosti veza karakterističnih parametara srednjih godišnjih protoka, 72 dvoparametarskih zakonitosti veza karakterističnih parametara maksimalnih godišnjih protoka, zajedno s parametrima maksimalnih protoka i volumena različitih povratnih razdoblja i 10 dvoparametarskih zakonitosti veza karakterističnih parametara minimalnih godišnjih protoka. Definirani su i teorijski hidrogrami 10-, 100- i 1000-godišnjeg povratnog razdoblja duž toka Kupe. Izdvojene su zakonitosti veza koje se mogu preporučiti za primjenu u praksi. Analiza višeparametarskih zakonitosti veza dala je dvije moguće troparametarske zakonitosti, međutim one nisu preporučljive za upotrebu zbog vrlo širokih intervala pouzdanosti, iako imaju visoke vrijednosti koeficijenta korelacije. Spektralna analiza protoka i oborina pokazala je da su se u razdoblju istraživanja (1981.-2012.) ekstremi protoka i oborina pojačali i više istaknuli, ali da se ukupna količina oborine i protoka smanjila u odnosu na ranije razdoblje (1951.-1980.). Ključne riječi: regionalna hidrološka analiza, spektralna analiza, protok, oborina, krš, sliv Kupe.Regional hydrological analysis was conducted using data from the catchments located in the area of karst basin of the Kupa river. The study included data from 32 hydrological profiles on 20 watercourses down to Kamanje on Kupa, Stative Donje on Dobra, Mrzlo polje on Mrežnica and Veljun on Korana profiles. Catchment area to specified profiles is approximately 5450 km2. The processed hydrological data are the average daily flows and the average, maximum and minimum annual flows. In addition to hydrological data, the daily rainfall data collected on climatological stations Parg, Ogulin and Karlovac were processed. The period of analysis is from 1981 to 2012, and the results were compared with the results of previous studies that analyzed the period from 1951 to 1980. The comparison of trends in mean annual flows, which also justifies the chosen period of analysis, has shown that in the earlier period from 1951 to 1980 eight time-sets showed a declining trend, and 11 time-sets showed growing trend, while in the analyzed period from 1981 to 2012, 20 time-sets showed a declining trend, and 12 time-sets showed growing trend. The maximum annual flows in the earlier period consisted of seven time-sets showing a declining trend and 12 time-sets showing the growing trend, while in the period of this analysis 27 time-sets showed a declining trend and five time-sets showed a growing trend. The minimum annual flows in the earlier period analysis consisted of seven time-sets showing a declining trend and 12 time-sets showing the growing trend, and in the period of this analysis, 15 time-sets have shown a declining trend, and 17 time-sets have shown a growing trend. The analysis of homogeneity of average, maximum and minimum annual flow for the 1981 to 2012 period in relation to the 1951 to 1980 period, shows that majority of non-homogeneous time-sets were present with average annual flows, while the majority of time-sets of maximum and minimum annual flows were homogeneous. The homogeneity of average annual flows confirms the assumption of a drier period, which occurred in the early 1980s and continues to this day. In this regional hydrological analysis, the following was conducted: 10 two-parameter models’ relationships of the average annual flow characteristic parameters, 72 two-parameter models’ relationships of the maximum annual flow characteristic parameters, together with the parameters of the maximum flow rate and the volume of different return periods and 10 two-parameter models’ relationships of the minimum annual flow characteristic parameters. Theoretical hydrographs of 10-, 100- and 1000-year return period along the Kupa river flow were defined. Two-parameters’ models that can be used in practice were selected. Although the analysis of multi-parameter relationships produced two possible three-parameter relationships, they are not recommended for use because of the very wide confidence interval, regardless of the correlation coefficient high value. Spectral analysis of the flows and precipitation shows that during the period of analysis from 1981 to 2012, extremes of flows and precipitation were strengthened and more pointed out, but the total amount of precipitation and flows declined, compared to the previous period from 1951 to 1980

Analiza trendova srednjih i maksimalnih protoka u ovisnosti o klimatskim promjenama - Primjer na krškim slivovima Hrvatske

U radu je analizirana ustrajnost i evolucija trendova srednjih i maksimalnih godišnjih protoka s hidroloških stanica na Kupi (Kupari, Kamanje), pritoku Čabranka (Zamost 2), Dobri (Stative donje, Trošmarija), Mrežnici (Mrzlo polje) i godišnjih oborina s tri meteorološke stanice (Parg, Ogulin i Karlovac). Rad je usredotočen na promatranje sedam veličina: srednji godišnji protok, srednji sezonski protok (srednji zimski i ljetni protok), trenutačni maksimalni godišnji protok, godišnja i sezonska količina oborine. Analizirani vremenski niz je od 1951. do 2013. godine, a fiksno razdoblje uzeto je od 1984. do 2013. godine. Vremenski niz svake razmatrane veličine je normiran na standardiziranu anomaliju toka, te je trend testiran Mann-Kendallovim Z testom, nakon čega je niz izglađen LOESS algoritmom. Analiza je izvedena za cijeli vremenski niz (primjerice, 1951.–2013., 1952.–2013. i tako dalje do 1984.–2013.). Time veličina uzorka varira od 63 do 30 godina. Standardizirana anomalija toka se tako lako može usporediti između različitih hidroloških stanica. Na svim analiziranim stanicama za sve analizirane veličine, nakon sredine 1980-ih godina kada počinje fiksno analizirano razdoblje, standardizirana anomalija toka ima niže vrijednosti od dugogodišnje srednje vrijednosti. Detaljnija analiza srednjih ljetnih i zimskih protoka pokazuje drukčije odstupanje od dugogodišnjeg prosjeka. Evolucija trenda razmatranih veličina je pokazana Mann-Kendallovim Z testom, prikazavši vrijednosti Z za početnu godinu svakog analiziranog vremenskog niza (od 1951. do 1984.).Persistence and evolution of trends of mean and high river flows from six hydrological stations on watercourses of the Kupa River (Kupari, Kamanje), tributary Čabranka (Zamost 2), Dobra River (Stative donje, Trošmarija), Mrežnica River (Mrzlo polje) and annual precipitation on three meteorological stations (Parg, Ogulin and Karlovac) were analysed. The paper focuses on seven indicators: annual mean flow, seasonal mean flows (winter and summer mean flows), instantaneous annual maximum flow, annual and seasonal precipitation. Analysed time series range from 1951 to 2013, and the fixed period ranges from 1984 to 2013. Time series of each indicator was scaled to standardized flow anomaly and was analysed using the Mann-Kendall Z test for monotonic trend, after which it is smoothed using LOESS algorithm. The analysis was conducted for each indicator for full record, e.g. 1951–2013, then 1952–2013 and so on until 1984–2013. Thus, the sample size varies from 63 to 30 years. The smoothed standardized flow anomaly is easily comparable among different hydrologic stations. The standardized flow anomaly on all analysed stations for all analysed indicators shows lower mean value than long-time average after mid-1980’s, when fixed period starts. Further analysis of summer and winter seasonal mean flows revealed different deviation from long-term annual flow average. Trend evolution of certain indicators was proven using Mann-Kendall Z test, by plotting Z values for each iteration of start year (1951 to 1984)

HIGH FLOWS FROM GORNJA DOBRA BASIN

U radu su na osnovi podataka s četiriju postojećih hidroloških stanica na slijevu Gornje Dobre razmatrani osnovni hidrološki pokazatelji. Definirane su i grafički prikazane krivulja učestalosti i krivulja trajanja srednjih dnevnih protoka u profilu Turkovići. Razmatrana je zakonitost veze maksimalnih srednjih godišnjih specifičnih dotoka u ovisnosti o veličini slijevova te o razmatranim hidrološkim profilima. Razmatrani su veliki vodni valovi iz 1999. i 2017. godine.The paper presents basic hydrological indicators based on data from the four existing hydrological stations on the Gornja Dobra basin. The frequency and flow-duration curves of mean daily flow in Turkovići profile are also defined and presented. The dependence of the mean maximum annual specific flows on the size of the influential basin to the considered hydrological profiles was considered. A review of a most recent high water event in 2017 was given

Mjerenja svjetlosnog onečišćenja u bliskom infracrvenom području na hrvatskim lokacijama

We investigate the light pollution (lP) in the near-infrared (NIR) part of the electromagnetic spectrum (700–1000 nm) for sites at low altitude, as typical for small observatories in this region. Our measurements show that considerable light pollution exists in the NIR. The increase of night sky brightness towards the horizon is often slightly slower in the NIR than in the visible. In cases when lP is mostly produced by high-pressure sodium lamps, the NIR part of light pollution is dominated by two close sodium spectral lines (818.3 and 819.5 nm) that can easily be filtered out with a dedicated filter. This can, however, change as sodium lamps are gradually replaced by metal-halide lamps whose spectra are complex, showing many lines over the whole visible/infrared range. If in the future a change to lED light sources happens, lP in the NIR could be reduced drastically. last, but not least, the low altitude of observing sites, together with climate characteristics of the region, result in a lot more humidity and aerosols in the atmosphere, compared to a typical mountaintop observatory site. This, combined with proximity of the polluting sources to the observing sites, results in enhancing the lP, compared to the clear, dry atmospheric conditions of a mountaintop observatory.Opisana su istraživanja svjetlosnog onečišćenja u bliskom infracrvenom dijelu elektromagnetnog spektra (700–1000 nm) za lokacije na malim nadmorskim visinama, što je tipično za male zvjezdarnice u ovom području. Mjerenja pokazuju da je i u bliskom infracrvenom području prisutno znatno svjetlosno onečišćenje. Porast svjetline neba odzenita prema obzoru često je puta nešto sporiji u infracrvenom nego u vidljivom. Uslučajevima kada je svjetlosno onečišćenje u najvećoj mjeri uzrokovano visokotlačnimnatrijevim žaruljama, infracrvenim dijelom svjetlosnog onečišćenja dominiraju dvije bliske natrijeve linije (818,3 i 819,5 nm) koje se lako mogu ukloniti odgovarajućim fiterom.To se može promijeniti u budućnosti jer se natrijeve žarulje postupno zamjenjuju metal-halidnim žaruljama čiji spektri su složeni, i sastoje se od mnoštva linija u cijelom vidljivom i infracrvenom dijelu spektra. Ako se u budućnosti dogodi prelazak na LED izvore svjetla, svjetlosno onečišćenje uinfracrvenom dijelu spektra bit će znatno smanjeno. I na kraju, zbog male nadmorske visine opažačkih lokacija, i klimatskih svojstava područja u kojem se one nalaze, u atmosferi je prisutno mnogo više vlage i aerosola nego što je slučaj na planinskim zvjezdarnicama. Ova činjenica u kombinaciji s blizinom izvora svjetlosnog onečišćenja dovodi do pojačavanja svjetlosnog onečišćenja u usporedbi s uvjetima čiste i suhe atmosfere tipične za planinske zvjezdarnice

Influence of groundwater quality indicators on nitrate concentrations in the Zagreb aquifer system

Nitrates presents one of the main groups of contaminants in the Zagreb aquifer system. Some natural groundwater quality indicators can have significant influence on their stability and mobility in the saturated zone. Correlation and multivariate statistical analyses were used to test the correlation of average values of NO3- with O2, ORP, pH, EC and temperature of groundwater, and to allocate observation wells that belong to the same clusters. ORP values didn`t relate to any observed variables, which is probably due to their variability which suggests changes in the oxidation-reduction conditions in the aquifer system. Principal component analysis was used for the determination of variables that are related to the nitrate concentrations and which were then used in cluster analysis. Other variables were excluded from cluster analysis. Three methods were used to perform cluster analysis, where the results calculated with Ward`s method were chosen as the most appropriate. In the end, two clusters were identified, one with smaller, and one with higher NO3-, O2 and EC values. Observation wells from cluster 1 are generally located near the Sava River and have similar nitrate concentrations. Lack of other nitrogen species and moderately aerobic conditions suggest very fast nitrification in the shallow Holocene aquifer.</p