Precipitation is a very important meteorological element in the Mediterranean region (MR) as its future change can impact human activities (e.g. water management, agriculture) and ecosystems. Significant progress has been made on climate projections for the MR . Future projections regarding seasonal precipitation show predominant reductions for spring, summer and autumn, however projections for winter are distinctly different . Precipitation is projected to decrease in all parts and all seasons (the most significant percent change occurs in summer) except for the northernmost parts in winter . This is in accordance with the expected drying over the MR as a part of global warming .
Precipitation variability and trends in the MR have been analyzed in many studies. For example, Ziv et al.  analyzed changes in the precipitation regime of Israel showing a statistically non-significant decreasing trend prevailing in most of the country. The majority of Israel has significant precipitation decrease only during spring. Luković et al.  examined spatial patterns of rainfall trends in Serbia suggesting only weak, mostly non-significant trends. The study of de Luis et al.  has shown a significant annual precipitation decrease in northwestern and western Slovenia and during all seasons, except autumn.
As local changes in meteorological variables in mid-latitudes are mainly controlled by atmospheric circulation [8, 9], the correlations between circulation indices and precipitation in the MR are very important to analyze. The relationships between atmospheric circulation pattern indices and precipitation in Slovenia have not been well identified: only a few studies [10, 11] have been made on this topic with only a limited number of precipitation stations investigated. One of the goals in this paper is to analyze these relationships in order to obtain a better understanding of the causes of precipitation variability in Slovenia. The study includes data on the large-scale North Atlantic Oscillation (NAO) and regional Mediterranean and Western Mediterranean Oscillations (MO and WeMO, respectively) known to affect the MR.
NAO is associated with a meridional dipole structure in sea level pressure with two centers of action located near Iceland and the Azores . A positive NAO phase leads to more intense precipitation over northern Europe, whereas a negative NAO phase causes a precipitation shift towards southern Europe . The influence of NAO on precipitation in the MR has been investigated by a number of authors [5, 8, 10–14]. A study by Sušelj and Bergant  showed significant negative correlation between NAOi and precipitation in Slovenia. However, this interpretation is limited by the fact that only four selected meteorological stations represented the whole country which is geomorphologically and climatologically diverse.
MO was defined in order to explain opposing atmospheric dynamics between the western and eastern part of the Mediterranean basin. The original MOi was defined as normalized pressure difference between Algiers and Cairo . A second version of this index, which was used in this paper, can be calculated as the difference of standardized pressure anomalies at Gibraltar and the Israeli meteorological station of Lod . The influence of MO on precipitation variability has been analyzed in numerous studies [5, 10, 11, 13, 17–19]. A study of Sušelj and Bergant  showed significant negative correlation between MOi and precipitation in Slovenia as registered at four selected meteorological stations (Ljubljana, Murska Sobota, RateČe and Postojna).
WeMO was defined by Martin-Vide and Lopez-Bustins  by means of the dipole composed by an anticyclone over the Azores and a depression over Liguria. This is the situation with a WeMO positive phase, while in the negative phase the situation is the opposite. We-MOi was defined as the result of the difference between standardized values in surface atmospheric pressure in San Fernando (Spain) and Padua (Italy). WeMOi’s influence on climate variability in the Iberian Peninsula has been analyzed by Martin-Vide and Lopez-Bustins  and Martin-Vide et al. .
The Republic of Slovenia is situated in the central-southern part of Europe (Figure 1) abutting four distinct geographical regions: the Mediterranean Sea, the Alps, the Dinaric Alps and the Pannonian Basin . Slovenia extends between 45°25’ and 46°30’ N and 13°23’ and 16°36’ E  and covers an area of 20,273 km2  with a population of 2.06 million. The Alpine macroregion is in the north of Slovenia, while the Mediterranean macroregion is in the west of Slovenia. Toward the east, the Mediterranean macroregion is replaced by the Dinaric macroregion that stretches in a northwest-southeast direction and covers most of the southern part of Slovenia. The Pannonian macroregion is a densely populated and intensively cultivated area at the east end of Slovenia  (Figure 1). Submediterranean, temperate continental and alpine climatic influences intertwine in the territory of Slovenia. However, most of Slovenia has a temperate continental climate. Alpine climate characterizes higher and lower mountain areas to the north and west of the country, while a submediterranean climate is present in the south and southwest of the country at the Adriatic coast (coastal sub-mediterranean climate) and its hinterland (inland sub-mediterranean climate). Continental climate intensifies with the distance increase from the Adriatic Sea and Alps-Dinaric mountain barrier towards the eastern and northeastern Slovenia .
In the study of de Luis et al.  it was discussed that changes in large-scale atmospheric circulation patterns may have contributed to an observed long-term drying in Slovenia. This study contributes to the investigation of these suggested relationships. The main goals of this paper are to investigate temporal and spatial variability and trends of annual and seasonal precipitation in Slovenia and to correlate them with indices of the large-scale (NAOi) and regional (MOi and WeMOi) atmospheric circulation patterns, which are more representative for MR precipitation.
2 Data and methods
Annual and seasonal precipitation in Slovenia recorded at 45 stations was analyzed (Figure 1,Table 1). Selected precipitation stations are located on the territory of each of the different geographical regions of Slovenia: 16 in the Alpine macroregion, 15 in the Dinaric macroregion, 10 in the Pannonian macroregion and 4 in the Mediterranean macroregion. Selection of adequate stations was based on the data availability and homogeneity as well as macroregions’ average size and altitudes.
The investigated period is from 1963 to 2012. Precipitation amounts were obtained from the Environmental Agency of the Republic of Slovenia (EARS). Winter (DJF), spring (MAM), summer (JJA) and autumn (SON) precipitation were calculated for each station using the standard seasons definition. Winter precipitation corresponds to January-February of the calendar year and to December of the previous year, while precipitation for other seasons corresponds to the months from the calendar year.
A standard Normal Homogeneity Test (SNHT) was applied for the detection of abrupt homogeneity breaks  in monthly precipitation values. The test is based upon the assumption that the difference between precipitation series at a candidate station (the one being tested) and the reference series is fairly constant in time. Reference series were chosen from 4 to 6 stations, based on distance, similar altitude and squared correlation coefficient from 0.3 to 0.8 with the test station. The critical level of this test was 95% . Inhomogenieties were detected and corrected .
Simple linear regression was used for obtaining annual and seasonal precipitation trends, while a Mann-Kendall nonparametric statistical test  was used to demonstrate the statistical significance of trends . Statistical significance was defined at the level of 95% and 99%. Rates of precipitation changes are expressed as %/decade, due to the differences in total precipitation amounts between regions .
In order to understand Slovenian precipitation and its relationship with atmospheric circulation patterns better, indices were examined using correlation analysis. Pearson’s correlation was used to reflect the degree of linear relationship between the precipitation and the atmospheric circulation pattern indices (NAOi, MOi and WeMOi). Monthly NAOi values were obtained from the National Oceanic and Atmospheric Association (NOAA) Climate Prediction Center (CPC) website . Daily values of MOi were obtained from Climatic Research Unit website . Monthly WeMOi data were obtained from the University of Barcelona website . Annual and seasonal NAOi and WeMOi were calculated using monthly series, while annual and seasonal MOi were calculated using daily series.
The spatial distribution of the results is displayed using spatial interpolation (an ordinary Kriging method) of the observed precipitation and precipitation trends for the 45 stations using the geostatistical software package AR-CGIS 10.1 with the Geostatistical Analyst Extension.
3.1 Results of homogenisation
During the homogeneity testing of precipitation, the detected break points were compared to metadata records in order to diagnose the causes of any observed inhomogeneity . This type of information was crucial for applying calculated corrections to the investigated series . In most cases, the break points were related to the relocation of a station. From 45 stations used in the paper, 23 were relocated during the investigated period. For instance, most breaks happened at the station Kozina (KZ) (26 breaks) which was relocated four times during the research period. In other cases, breaks were related to missing values.22 stations had missing values, but they did not exceed 5% of each station dataset. After a series of individual or multiple homogeneity adjustments  conducted within this study, the series were considered to be homogeneous. The adjustment values of the monthly time series usually ranged from −5 to 5 mm.
3.2 Precipitation and precipitation regimes
The highest annual precipitation amounts (>2400 mm) were registered at stations located in the northwestern, mountainous part of Slovenia, influenced by interaction between alpine and submediteranean air masses. Towards the east, continental climate influence prevails with the lowest precipitation amounts recorded in the northeastern, Pannonian part of the country (<800 mm) (Figure 2a).
During winter, the highest precipitation amounts are registered at stations located in the northwestern, mountainous part of Slovenia (550–650 mm) influenced by alpine climate. Southwestern Slovenia is influenced by submediterranean climate and receives between 250 and 350 mm. The largest part of the country receives less than 250 mm and is influenced by temperate continental climate (Figure 2b).
In spring, western mountainous Slovenia is still the wettest part of the country (550–650 mm), while the largest part of the country receives more precipitation (250– 350 mm) compared to winter. Northeastern Slovenia, influenced by continental climate, receives less than 250 mm (Figure 2c).
Summer is characterized by a significant increase of precipitation in the eastern part of the country, influenced by continental climate, and reaching its seasonal precipitation maximum (250–300 mm). The largest part of the country receives between 350 and 450 mm, while northwestern Slovenia receives between 450 and 550 mm (Figure 2d).
In autumn, the seasonal precipitation maximum is evident in the area of alpine (northwestern Slovenia) and submediterranean climate (southwestern Slovenia) with >750 mm and from 450 mm to 550 mm, respectively (Figure 2e).
3.3 Precipitation trends
A non-significant annual precipitation decrease was registered throughout Slovenia. However, statistically significant negative trends (from −3% to −6% per decade, i.e. from −28 mm per decade to −127 mm per decade) were registered at 13 stations out of 45, mainly located in southwestern and northwestern Slovenia (Figure 3a).
During winter, non-significant negative trends were noted over the majority of the country (36 out of 45 stations). The largest decrease was noted in northeastern (from −4% to −7% per decade) as well as northwestern Slovenia and near the Adriatic Sea (from −4% to −6% per decade). Only one small part of southern Slovenia is characterized by non-significant positive trends (Figure 3b).
Spring precipitation decrease was noted in the whole country. Non-significant negative trends are registered in central (from −4% to −6% per decade), western and northeastern Slovenia (from −6% to −8% per decade). However, a statistically significant decrease was registered at only three stations near the Adriatic coast (from −6% to −10% per decade, i.e. from −24 mm per decade to −49 mm per decade) (Figure 3c).
A decrease in summer precipitation was noted over a majority of the country (44 out of 45 stations). A statistically significant precipitation decrease was observed at 13 out of 45 stations mainly in southwestern Slovenia (from −4% to −10% per decade, i.e. from −20 mm per decade to −46 mm per decade), where influences of submediterranean and continental climate intertwine (Figure 3d).
Autumn in Slovenia was characterized by a non-significant precipitation increase over the majority of the country (35 out of 45 stations), with negative trends (from −2% to −4% per decade) noted only in the west of the
country. The largest increase was observed in central Slovenia (from 2% to 4% per decade) (Figure 3e).
3.4 The correlations between atmospheric circulation patterns and precipitation
In general, correlations between MOi, NAOi and precipitation in Slovenia are negative, while WeMOi and precipitation have positive correlations on annual and seasonal scales (Table 2). This suggests that precipitation in Slovenia is decreasing during positive NAO and MO phases, while the positive phase of WeMO results in more precipitation in Slovenia.
Annual precipitation in Slovenia was significantly influenced by WeMOi at 21 out of 45 stations (significant correlations from 0.3 to 0.6), MOi at 17 out of 45 stations (significant correlations from −0.3 to −0.4) and NAOi at 10 out of 45 stations (significant correlations from −0.3 to −0.4) (Table 2). The spatial pattern of these relationships showed that WeMOi influence is dominant in central and eastern Slovenia, while MOi and NAOi influence is dominant in western Slovenia with the larger area under the MOi influence (Figure 4).
The strongest correlations between NAOi, MOi and seasonal precipitation in Slovenia are noticed in winter. Significant negative correlations (from −0.3 to −0.7) between MOi and precipitation are present in the majority of the country (43 out of 45 stations) (Table 2). Only stations located in southeastern Slovenia are not significantly influenced by this atmospheric circulation pattern. Similar results are obtained between NAOi and precipitation, but with smaller correlation values (from −0.3 to −0.6) and with a smaller covered area (32 out of 45 stations) (Table 2). Eastern Slovenia is not covered by significant NAOi influence. Significant WeMOi influence is noticed at 31 out of 45 stations with correlation values ranging from 0.3 to 0.6 (Table 2). Central, southeastern Slovenia and the area near the Adriatic Sea are not significantly influenced by this circulation (Figure 4).
Only WeMOi significantly influences spring precipitation in the larger part of Slovenia. Compared to this, correlations between MOi, NAOi and precipitation are rather small and non-significant. WeMOi is positively correlated (from 0.3 to 0.5) with precipitation throughout the country (40 out of 45 stations) (Table 2), except for small area in the north and northeast (Figure 4).
During summer, the precipitation distribution in the majority of the country is not significantly influenced by the investigated atmospheric circulation patterns. It might be that local factors (i.e. orography) shield certain regions from the variability represented by the atmospheric modes. As noticed in previous research, at fine geographical scales the effects of atmospheric circulation are modified by topography, particularly in areas of complex terrain [37, 38]. Significant influence (from −0.3 to −0.4) of MOi is noticed in eastern Slovenia and WeMOi in northwestern Slovenia (from 0.3 to 0.4) (Table 2). Significant NAOi influence (-0.3) (Table 2) is registered at only two stations, located in the northwestern part of the country (Figure 4).
Non-significant correlations were found between MOi, NAOi and autumn precipitation in Slovenia. Compared to this, WeMOi is significantly correlated (from 0.3 to 0.5) with precipitation in the majority of the country, except for small areas in central and northern Slovenia (Table 2) (Figure 4).
4 Discussion and conclusions
The statistical analysis of annual and seasonal data from a network of precipitation stations in Slovenia from 1963 to 2012 has allowed for quantitatively characterizing precipitation variability in the study area and for assessing similarities and differences with respect to precipitation fluctuations in other areas of the MR.
The highest precipitation amounts are registered at the mountains in western Slovenia with a decrease towards the northeast of the country. This is due to the fact that western Slovenia is exposed to the inflow of moisture from the Adriatic Sea and to topographically-induced precipitation by the Alps and the Dinaric Alps.
Negative annual and seasonal (except autumn) precipitation trends are observed. A significant precipitation decrease was noticed in spring (from −6% to −10% per decade) and summer (from −4% to −10% per decade) and at an annual timescale (from −3% to −6% per decade) in southwestern and western Slovenia. Non-significant decreasing trends (up to −7% per decade) during winter and non-significant increasing trends during autumn (up to 4% per decade) were registered in the majority of the country. Compared to the study of de Luis et al.  that analyzed precipitation in Slovenia for the 1950-2007 period, this study obtained higher negative trends during spring and summer and smaller during winter, while annual trends had the same values. Annual and seasonal trends from our study agree with trends derived from E-OBS gridded observations . ERA-Interim meteorological reanalysis  and results from our study showed increasing trend of precipitation during autumn and decreasing trend during spring, while they disagree on the winter and summer trends. Trends from NCEP/NCAR R1 meteorological reanalysis  and trends from our study disagree during all seasons, except for the autumn.
By the end of the 21st century it is expected that precipitation in Slovenia will continue to decrease in summer months (up to 20 %), increase in winter (up to 30%) and show no significant changes in spring and autumn . Furthermore, results from high-resolution climate change simulations over the MR showed substantial precipitation increases in winter (>25%) and spring (from 10% to 25%) and a decrease in summer (from −10% to −25%) and a small change in autumn precipitation (from −5% to 5%) in Slovenia by the end of the 21st century . Compared to these studies, our results showed significant drying during summer and non-significant changes during autumn, and this is compatible with model projections for the future. Observed winter and spring trends are not compatible with climate model projections.
Annual and seasonal precipitation in the MR shows no uniform trend. Weak or non-significant trends for precipitation in the past century have been found at the Mediterranean scale , in Serbia , Israel , northwestern Italy , in the Alpine region , etc. Seasonal trends indicate a slight decrease in winter and spring and an increase in autumn precipitation in Serbia . Lopez-Bustins et al.  noticed a significant decrease of winter rainfall at the Iberian Peninsula in its western and central areas throughout the second half of the 20th century, whereas over the eastern fringe it showed little variation. Obtained trends in this study together with a projected future precipitation decrease in the MR [2, 4] that is going to be most pronounced in summer  could imply that these changes have already started in Slovenia, which could lead to an increased economic and social vulnerability in the country due to reduced water availability in the future. Results from this study show drying in the spring and summer seasons as in the Coupled Model Intercomparison Project phase 5 (CMIP5) models, but the observed trends are opposite for winter and autumn seasons compared to the modeled trends. Observed trends also have higher values when compared to the modeled trends .
Correlations between NAOi, MOi and annual and seasonal precipitation in Slovenia are negative. When NAO is in its positive phase, low-pressure anomalies over the Icelandic region and throughout the Arctic combine with high-pressure anomalies across the subtropical Atlantic to produce stronger than average westerlies across the midlatitudes. During a positive NAO, conditions are drier over the MR , including Slovenia, as noticed in our study. The negative NAO index phase shows a weak subtropical high and a weak Icelandic low. The reduced pressure gradient results in fewer and weaker winter storms crossing on a more west-east pathway and bringing moist air into the Mediterranean  and increasing precipitation amounts into Slovenia. The positive mode of MO is related to anticyclonic conditions in the western Mediterranean and a trough in the east, and with below-average rainfall rates in the entire Mediterranean basin , including Slovenia. In its negative mode, a low pressure region is located near the British Isles or north of the Iberian Peninsula while anticyclonic conditions prevail in the Mediterranean. This situation is related with rainfall events in the western part of the Mediterranean basin . Results from our study indicate more precipitation in Slovenia during the positive MO phase. NAOi and MOi significantly influence winter precipitation. In spring and autumn their significant influence is not registered, while in summer it is limited to a small area. Statistically significant correlations are stronger for MOi than for NAOi.
Correlations between WeMOi and annual and seasonal precipitation in Slovenia are positive. The positive phase of the WeMO corresponds to an anticyclone over the Azores and low-pressures in the Liguria Gulf , resulting in higher precipitation amounts in the larger part of Slovenia in all seasons except for summer when its influence is spatially limited. The WeMO negative phase coincides with a central European anticyclone located north of Italy and a low-pressure centre in the framework of the Iberian southwest  leading to a precipitation decrease in Slovenia.
NAOi shows a positive and significant (at 95% level) trend in the second half of the 20th century . The trend of this atmospheric circulation index is consistent with the reduction in winter precipitation throughout Slovenia registered in this paper and in the study of de Luis et al. , and over most of the Iberian Peninsula at the end of 20th century . Also, NAOi displays a strong, negative correlation with winter  and spring precipitation in Italy  and at high altitudes in the Alps [46, 52]. Except with mean precipitation amounts, NAOi is negatively correlated with the frequency of extreme precipitation days over the northwestern MR in the period 1961-2000. The correlations are rather small during autumn (October-November) but are quite considerable during the rest of the rainy season (December-January, February-March) .
MO is strongly linked in winter to NAO . An observed increase in MOi during the second half of the 20th century [17, 19] led to smaller precipitation amounts south from 50°N  which is in accordance with a winter precipitation decrease in Slovenia when its influence is the strongest.
WeMOi is significantly reduced in winter throughout the second half of the 20th century  with WeMO entering an extreme negative phase in the 1990s. This recent WeMOi decay leads to a rainfall reduction over the northern fringe of the Iberian Peninsula  and torrential rainfall reduction in the northeastern Iberian Peninsula . A significant increase in sea-level pressure in northern Italy has been detected during the twentieth century  that could contribute to the precipitation decrease in Slovenia in all seasons except autumn. In autumn, a large increase in cyclone activity was identified in the Gulf of Genoa and the southern part of the Adriatic Sea that could be responsible for the positive trend in autumn precipitation [54–56].
Results from this study contribute to a better understanding of relationships between atmospheric circulation patterns and precipitation variability in this transitional area. It is shown that the influence of NAO on precipitation variability over Slovenia is smaller than the effects of the atmospheric circulations belonging to the Mediterranean area (namely WeMO and MO). WeMO appeared as the most dominant atmospheric circulation pattern influencing annual and seasonal precipitation variability and distribution in the Republic of Slovenia, except for winter when MO is the most significant atmospheric circulation pattern. Relationships between other weather variables (e.g. temperature) and atmospheric circulation patterns could be investigated in future papers in order to acquire a more detailed picture of climatic change in this country.
This research is supported by the project no. 43002 financed by the Ministry of Education, Science and Technological Development of the Republic of Serbia.
Lionello P., Abrantes F., Gacic M., Planton S., Trigo R., Ulbrich U., The climate of the Mediterranean region: research progress and climate change impacts. Reg. Environ. Change, 2014, 14, 1679-1684 Google Scholar
Jacobeit J., Hertig E., Seubert S., Lutz K., Statistical downscaling for climate change projections in the Mediterranean region: methods and results. Reg. Environ. Change, 2014, 14, 1891-1906 Google Scholar
Dubrovský M., Hayes M., Duce P., Trnka M., Svoboda M., Zara P., Multi-GCM projections of future drought and climate variability indicators for the Mediterranean region. Reg. Environ. Change 2014, 14, 1907-1919 Google Scholar
IPCC Intergovernmental Panel on Climate Change, The Physical Science Basis, Summary for Policymakers (contribution of WG I to the 4th Assessment Report of the IPCC), Cambridge and New York: Cambridge University Press, 2007 Google Scholar
Ziv B., Saaroni H, Pargament R., Harpaz T., Alpert P., Trends in rainfall regime over Israel, 1975–2010, and their relationship to large-scale variability. Reg. Environ. Change, 2014, 14, 1751-1764 Google Scholar
Luković J., Bajat B., Blagojević D., Kilibarda M., Spatial pattern of recent rainfall trends in Serbia (1961–2009). Reg. Environ. Change, 2014 14, 1789-1799 Google Scholar
de Luis M., Čufar K., Saz M.A., Longares L.A., Ceglar A., Kajfež-Bogataj L., Trends in seasonal precipitation and temperature in Slovenia during 1951–2007. Reg. Environ. Change, 2014, 14, 1801-1810 Google Scholar
Hurrell J.W., Decadal trend in the North Atlantic oscillation: regional temperature and precipitation. Science, 1995, 269, 676-679 Google Scholar
Hurrell J.W., Van Loon H., Decadal variations in climate associated with the North Atlantic oscillation. Clim. Chang., 1997, 36, 301-326 Google Scholar
Sušelj K., Bergant K., Mediterranean Oscillation Index. Geo-phys. Res. Abstr., 2006a, 8, 2145 Google Scholar
Sušelj K., Bergant K., Sredozemski oscilacijski indeks in vpliv na podnebje Slovenije [Mediterranean Oscilation index and its influence on the climate of Slovenia]. In: Kozmus K, Kuhar M(Ed.), Raziskave s podroČja geodezije in geofizike: zbornik predavanj [Researches in geodesy and geophysics: collection of lectures]. Faculty of Civil and Geodetic Engineering, 2006b, Ljubljana (in Slovenian) Google Scholar
Krichak S.O., Breitgand J.S., Gualdi S., Feldstein S.B., Teleconnection-extreme precipitation relationships over the Mediterranean region. Theor. Appl. Climatol., 2014, 117, 679-692 Google Scholar
Brunetti M., Maugeri M., Nanni T., Atmospheric circulation and precipitation in Italy for the last 50 years. Int. J. Climatol., 2002, 22, 1455-1471 Google Scholar
Lopez-Bustins J.A., Martin-Vide J., Sanchez-Lorenzo A., Iberia winter rainfall trends based upon changes in teleconnection and circulation patterns. Glob. Planet. Chang., 2008, 63, 171-176 Google Scholar
Conte M., Giuffrida S., Tedesco S., The Mediterranean oscillation: impact on precipitation and hydrology in Italy. In: Proceedings of the Conference on Climate and Water, Vol. 1. Publications of Academy of Finland, Helsinki, 1989, 121-137 Google Scholar
Palutikof J.P., Analysis of Mediterranean climate data: measured and modelled. In: Mediterranean Climate-Variability and Trends, Bolle HJ (ed.). Springer-Verlag, Berlin, 2003, 133-153 Google Scholar
Piervitali E., Colacino M., Conte M., Signals of climatic change in the central–western Mediterranean basin. Theor. Appl. Climatol., 1997, 58, 211-219 Google Scholar
Kutiel H., Paz R., Sea level pressure departures in the Mediterranean and their relationship with monthly rainfall conditions in Israel. Theor. Appl. Climatol., 1998, 60, 93-109Google Scholar
Dünkeloh A., Jacobeit J., Circulation dynamics of Mediterranean precipitation variability 1948–98. Int. J. Climatol., 2003, 23, 1843-1866 Google Scholar
Martín-Vide J., Lopez-Bustins J.A., The Western Mediterranean Oscillation and rainfall in the Iberian Peninsula. Int. J. Climatol., 2006, 26(11), 1455-1475 Google Scholar
Martin-Vide J., Sanchez-Lorenzo A., Lopez-Bustins J.A., Cor-dobilla M.J., Garcia-Manuel A., Raso J.M., Torrential Rainfall in Northeast of the Iberian Peninsula: Synoptic patterns and WeMO influence. Advances in Science and Research, 2008, 2, 99-105 Google Scholar
Orožen AdamiČ M., About Slovenia. In: Orožen AdamiČ M (Ed.), Slovenia: a geographical overview. ZRC SAZU, Ljubljana, 2004, 7-9 Google Scholar
Ogrin D., Prut D. Aplikativna fziČna geografija Slovenije [Applicative physical geography of Slovenia]. Znantstvena založba Fikozofske fakultete, Ljubljana, 2009, 13. (in Slovenian) Google Scholar
Perko D., The regionalization of Slovenia. Geografski zbornik, 1998, 38, 12-57 Google Scholar
Ogrin D., Modern climate change in Slovenia. In: Orožen AdamiČ M (Ed.), Slovenia: a geographical overview. ZRC SAZU, Ljubljana, 2004, 45-50 Google Scholar
Alexandersson H., A homogeneity test applied to precipitation data. J. Climate, 1986, 6, 661-675 Google Scholar
Khaliq M.N., Ouarda T., On the critical values of the standard normal homogeneity test (SNHT). Int. J. Climatol., 2007, 27, 681-687 Google Scholar
Štěpanek P., AnClim − software for time series analysis. Department of Geography, Faculty of Natural Sciences, MU, Brno, 1.47 MB, 2007 http://www.climahom.eu/AnClim.html
Sneyers R., On the statistical analysis of series of observations. World Meteorological Organization, Technical Note, Genève, 1991, 415, 192 Google Scholar
Salmi T., Mättä A., Anttila P., Ruoho-Airola T., Amnell T., Detecting trends of annual values of atmospheric pollutants by the Mann-Kendall test and Sen’s slope estimates. The Excel template application MAKESENS. Finnish Meteorological Institute, Helsinki, 2002, 1-35 Google Scholar
National Oceanic and Atmospheric Association (NOAA) Climate Prediction Center (CPC) website, 2014 http://www.cpc.ncep. noaa.gov/products/precip/CWlink/pna/nao.shtml
Climatic Research Unit website, 2014 http://www.cru.uea.ac. uk/cru/data/moi/
University of Barcelona website, 2014 http://www.ub.edu/gc/ English/wemo.htm
Savić S., Milovanović B., Lužanin L., Lazić L., Dolinaj D., The variability of extreme temperatures and their relationship with atmospheric circulation: the contribution of applying linear and quadratic models. Theor. Appl. Climatol., 2015, 121, 591-604 Google Scholar
Savić S., Petrović P., Milovanović B., Homogenisation of mean air temperature data series from Serbia. European Geosciences Union-General Assembly, Vienna, Austria, 2010, Geophysical Research Abstract Vol. 12, EGU2010-5521-1 Google Scholar
Moberg A., Alexandersson H., 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., 1997, 17, 35-54 Google Scholar
Fernandez J., Sáenz J., Zorita E., Analysis of wintertime atmospheric moisture transport and its variability over southern Europe in the NCEP reanalyses. Clim. Res., 2003, 23, 195-215. Google Scholar
Bojariu R., Giorgi F., The North Atlantic Oscillation signal in a regional climate simulation for the European region. Tellus, 2005, 57A(4), 641-653. Google Scholar
Haylock M.R., Hofstra N., Klein Tank A.M.G., Klok E.J., Jones P.D., New M., A European daily high-resolution gridded dataset of surface temperature and precipitation. J. Geophys. Res (Atmospheres), 2008, 113, D20119, CrossrefGoogle Scholar
Dee D.P., Uppala S.M., Simmons A.J., Berrisford P., Poli P., Kobayashi S., Andrae U., Balmaseda M.A., Balsamo G., Bauer P., Bechtold P., Beljaars A.C.M., van de Berg L., Bidlot J., Bormann N., Delsol C., Dragani R., Fuentes M., Geer A.J., Haimberger L., Healy S.B., Hersbach H., Hólm E.V., Isaksen L., Kållberg P., Köhler M., Matricardi M., McNally A.P., Monge-Sanz B.M., Morcrette J.-J., Park B.-K., Peubey C., de Rosnay P., Tavolato C., Thépaut J.-N., Vitarta F., The ERA-Interim reanalysis: configuration and performance of the data assimilation system. Q. J. Roy. Meteor. Soc., 2011, 137, 553-597. Google Scholar
Kalnay E., Kanamitsu M., Kirtler R., Collins W., Deaven D., Gandin L., Iredell M., Saha S., White G., Woollen J., Zhu Y., Chelliah M., Ebisuzaki W., Higgins W., Janowiak J., Mo K.C., Ropelewski C., Wang J., Leetma A., Reynolds R., Jenne R., Joseph D., The NCEP/NCAR 40-year reanalysis project. Bull. Amer. Meteorol. Soc., 1996, 77, 437-471. Google Scholar
Bergant K., Projections of Climate Change for Slovenia. In: Jurc M (Ed.), Climate Change: impact on forests and forestry. Studia forestalia Slovenica, 130, 67-86. Google Scholar
Gao X., Pal J.S., Giorgi F., Projected changes in mean and extreme precipitation over the Mediterranean region from a high resolution double nested RCM simulation. Geophys Res Lett, 2006, 33, L03706, . CrossrefGoogle Scholar
Norrant C., Douguedroit A., Monthly and daily precipitation trends in the Mediterranean (1950–2000). Theor. Appl. Climatol., 2006, 83, 89-106 Google Scholar
Ciccarelli N., von Hardenberg J., ProvenzaleA., Ronchi C., Vargiu A., Pelosini R., Climate variability in north-western Italy during the second half of the 20th century. Glob. Planet. Chang., 2008, 63, 185-195 Google Scholar
Beniston M., Mountain climates and climatic change: an overview of processes focusing on the European Alps. Pure and Applied Geophysics, 2005, 162, 1587-1606 Google Scholar
Visbeck M.H., Hurrell J.W., Polvani L., Cullen H.M., The North Atlantic Oscillation: past, present, and future. Proc. Natl. Acad. Sci. U.S.A., 2001, 98, 23, 12876-12877. Google Scholar
Rousi E., C. Anagnostopoulou C., Tolika K., Maheras P., Bloutsos A., ECHAM5/MPI General Circulation Model Simulations of Teleconnection Indices over Europe. In: Helmis CG (Ed.), Advances in Meteorology, Climatology and Atmospheric Physics. Springer Berlin Heidelberg, 709-715. Google Scholar
Angulo-Marti?nez M., Santiago Begueri?a S., Do atmospheric teleconnection patterns influence rainfall erosivity? A study of NAO, MO and WeMO in NE Spain, 1955-2006, J. Hydrol., 2012, 450-451, 168-179. Google Scholar
Wibig J., Precipitation in Europe in relation to circulation patterns at the 500 hPa level. Int. J. Climatol., 1999, 19, 253-269 Google Scholar
Beniston M., Jungo P., Shifts in the distributions of pressure, temperature and moisture and changes in the typical weather patterns in the Alpine region in response to the behavior of the North Atlantic Oscillation. Theor. Appl. Climatol., 2002, 71, 29-42 Google Scholar
Maugeri M., Brunetti M., Monti F., Nanni T., Sea-level pressure variability in the Po plain (1765–2000) from homogenized daily secular records. Int. J. Climatol., 2004, 24, 437-455 Google Scholar
Bartholy J., Pongracz R., Pattanyus-Abraham M., Analysing the genesis, intensity and tracks of western Mediterranean cyclones. Theor. Appl. Climatol., 2009a, 96, 133-144 Google Scholar
Bartholy J., Pongracz R., Pattanyus-Abraham M., European cyclone track analysis based on ECMWF ERA-40 data sets. Int. J. Climatol., 2009b, 26, 1517-1527Google Scholar
Lionello P., Zardini, Characteristics of the cyclonic activity in the Mediterranean sea during the last four decades of the 20th Century. Geophys. Res. Abstr., 2003, 5, 8316 Google Scholar
About the article
Published Online: 2016-12-02
Published in Print: 2016-01-01
Citation Information: Open Geosciences, Volume 8, Issue 1, Pages 593–605, ISSN (Online) 2391-5447, DOI: https://doi.org/10.1515/geo-2016-0041.
© 2016 Dragan D. Milošević et al., published by De Gruyter Open. This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License. BY-NC-ND 3.0