Application of Mann-Kendal (MK) test in trend analysis of air temperature and precipitation: Case of Mačva district (Serbia)

Recent climate changes cause significant natural and socio-economic consequences. They represent one of the major environmental problems of the late 20th and early 21st centuries. Changes in temperature and precipitation play a significant role in understanding climate change issues. They include numerous extreme climatic events such as heat waves, droughts, forest fires and more. Looking at regional differences in temperature and precipitation regime change, Southern Europe, including the Republic of Serbia, occupies a special place. The Mačva district (3.272 km²) is almost four times as spacious as the Mačva area. The administrative-political division of the Mačva district is comprised of eight municipalities. The paper presents trends of two climate variables: mean annual air temperature and mean annual precipitation in the study area. In methodological sense, the main statistical procedure is the non-parametric Mann-Kendall (MK) test. Data from three available meteorological stations in the Mačva district (1949-2015) were used for the analysis. The presented results of the trends in air temperature indicate that there is a statistically significant positive trend in all-time series. In trends, precipitation amounts a statistically significant positive trend was observed in two time series, while in one there is no trend. The expressed trends, especially in the case of air temperatures, lead to the possibility of drought. Mačva district and Mačva have some agricultural importance in the Republic of Serbia. For these reasons, some adaptation to climate change is needed as arid conditions lead to fluctuations in agricultural yield

GIS and geographical analysis of the main harbors in the world

This paper points out the possibilities of better exploitation of marine traffic as well as its connection with other kinds of traffic. Special attention is given to the analysis of 1,081 harbors about their availability during the year. The methods and algorithms used in GIS are buffers, cluster, method of interpolations, and network analysis. The methods used for the purpose of conducting numerical analyses are algorithms that served for the analysis of the network, its transport features, and the connectivity with harbors in terms of geospace. The main results found in this research showed that harbors have good connectivity in the first place with road traffic and after that with air and railroad traffic. According to data from 2019, all traffic lines cover 4.1 × 1015 km, and the road traffic has the most significant potential in connection with the harbors. The most connected harbors and airports are in the east coast of North America, west coast, north Europe, southern Europe, south-east Australia, a central part of Oceania, and south-east Africa. The results in the modified Likert scale between airports and harbors showed medium results. The densest road network is located in the eastern part of USA, western and central part of Europe, and east coast of China. The number of possible connected lines between main road nodes and harbors is 0.8 × 109. This type of traffic showed excellent results and connection with harbors. The number of possible connected lines per month between railroads and harbors is 1.3 × 103. This type of traffic showed low connectivity with the harbors. In the end comparison of harbors with air, road and railroad networks were established. The geographical position of harbors was analyzed, and better understanding was performed on a global scale

Assessment of air temperature trend in South and Southeast Bosnia and Herzegovina from 1961 to 2017

Recent climate change has been caused by interaction of natural processes and the anthropogenic factor. In turn, it incites the pronounced natural and socio-economic changes. It is the air temperature that plays a pertinent role in understanding the climate change problem. Southeast Europe, including Bosnia and Herzegovina (B&H), is highly relevant for the observations of regional differences in changes of air temperature regime. From the regional-geographical point of view, South and Southeast B&H cover 26.5% (13.568 km²) of B&H territory (51.209 km²). It is from south and southeast that the Mediterranean impacts from the Adriatic Sea penetrate into the defined region, which further affects the variability of climate conditions in B&H. The paper presents trends in three parameter categories: mean annual, mean maximum, and mean minimum air temperatures in the territory of South and Southeast B&H. The aim of the paper is to demonstrate the likely climate change based on air temperature trends. Methodologically, temperature trends were processed by using the Mann-Kendall trend test. For the purpose of the analysis, available data from four meteorological stations in South and Southeast B&H for a 56-year period were used. Based on the obtained results, a statistically relevant positive trend was observed in all twelve time series. According to the analyzed trends, the increase of air temperature was dominant in the target area. The application of Geographical Information System (GIS) tools indicated the presence of regional differences in air temperature distribution. An evident phenomenon is the combined impact of the orography of the region and the maritime influence. The occurring climate change affects specific social sectors, so the problem must be addressed properly. Another pertinent fact is that the climate change problem has not been adequately analyzed in the strategic documents in B&H

Assessing average annual air temperature trends using the Mann–Kendall test in Kosovo

The annual trends of surface mean monthly air temperature and monthly extreme temperatures were analyzed from ten meteorological stations in Kosovo. The data refer to observation periods between 1949 and 1999 for four stations, and observation periods between 1965 and 1999 for the remaining six stations. Trends were analyzed for nine time series. Positive trends were found in six series, and negative trends were found in three series. After an assessment of these trends using the Mann–Kendall test, positive trends were confirmed in four series, a negative trend was confirmed in one series, and in one series there was no trend, whereas trends were characterized as slightly positive in two time series and slightly negative in one series

Assessing average annual air temperature trends using the Mann-Kendall test in Kosovo

The annual trends of surface mean monthly air temperature and monthly extreme temperatures were analyzed from ten meteorological stations in Kosovo. The data refer to observation periods between 1949 and 1999 for four stations, and observation periods between 1965 and 1999 for the remaining six stations. Trends were analyzed for nine time series. Positive trends were found in six series, and negative trends were found in three series. After an assessment of these trends using the Mann-Kendall test, positive trends were confirmed in four series, a negative trend was confirmed in one series, and in one series there was no trend, whereas trends were characterized as slightly positive in two time series and slightly negative in one series

Spatiotemporal variability of air temperatures in Central Serbia from 1949 to 2018

The paper presents trends for three categories of variables: average annual, average maximum and average minimum air temperatures. Data was provided by the meteorological yearbooks of the Republic Hydrometeorological Service of Serbia. The main goal of this paper is to detect possible temperature trends in Central Serbia. The trend equation, trend magnitude, and Mann-Kendall non-parametric test were used in the analysis of climate parameters. The used statistical methods were supplemented by GIS numerical analysis, which aimed to analyze the spatial distribution of isotherms from 1949 to 2018. The obtained results indicate that out of the 72 analyzed time series, an increase in air temperature is dominant in 61 time series, while 11 time series show no changes. The highest increase was recorded in the average maximum time series (4.2 °C), followed by an increase of 3.5°C in average maximum air temperatures. The highest increase in the average annual time-series was 3.0 °C. The lowest increases in air temperature were recorded in the average minimum time series (0.1 and 0.2 °C). In two average minimum time series a decrease in average air temperatures was identified (-0.6 and -0.4 °C. The application of GIS tools indicates the existence of interregional differences in the arrangement of isotherms, leaded by the orography of the terrain. In the spatial distribution of the analyzed variables, "poles of heat" and "poles of cold" stand out, and the influence of the urban heat island is evident (especially in the case of the urban agglomeration of Belgrade). The manifested spatial patterns of air temperature need to be further examined and the correlation with possible causes need to be determined. For these reasons, the paper provides a solid basis for studying the climate of this area in the future, as it provides insight into climate dynamics over the past decades

Spatial analysis of air temperature and its impact on the sustainable development of mountain tourism in Central and Western Serbia

Empirical studies of the late twentieth and early twenty-first century indicate the existence of a growth trend in air temperature. This trend is particularly pronounced in the region of Southern Europe, including the Republic of Serbia. Many problems occur in the socio-economic areas due to global warming, which directly influences the development of tourism. In this study, we will deal with the influence of climate change on the sustainable development of mountain tourism in the area of the western and central Serbia tourist zones, which includes Starovlaška and Kopaonik mountain chain. The data on changes in the temperature of air will be gathered at six different altitude meteorological stations, for the period from 1990 to 2014. All weather stations in the studied area were classified into three groups: lowland, middle and high mountain. In order to obtain trends, three sets of data were used: the average monthly temperature, the maximum monthly temperature, and the monthly minimum temperature, recorded in each station. The seasonal classification has been conducted based on four seasons: spring,m summer, autumn, and winter. Three statistical approaches were used to analyze the temperature trends in 15 time series, for each group of stations individually. First, the trend equation was calculated for each time series, then, completely separate from the first approach, all trends were assessed using the Mann-Kendall test, and in the end, in all cases, the trend magnitude was calculated based on the trend equation. The results show that there is a significant positive trend of temperature rise on an annual basis, while the trend is significantly positive during the fall and spring seasons. In winter, the trend is slightly positive or absent, while in the summer trend is moderately positive in all three groups of stations

Assessment of observed and projected climate changes in Bačka (Serbia) using trend analysis and climate modeling

Climate change is one of the largest environmental issues causing hydroclimatological extremes such as floods, droughts, and aridity. The aim of this study is to assess the observed and projected climate changes in Bačka (Serbia). Detailed trend analyses and possible climate scenarios over Bačka has not been presented up to now. In this paper, four data sets were extracted and calculated: mean annual air temperature, mean air temperatures during the vegetation period, mean annual precipitation and total precipitation during the vegetation period. The presented parameters were obtained from the annual meteorological reports of the Republic Hydrometeorological Service of Serbia. Trend equation based on linear regression, trend magnitude according to the trend equation, and Mann-Kendall statistics have been used for trend analysis of climatic parameters. A GIS modeling of the possible climate scenario was created according to the Beijing Climate Center Climate System Model (BCC-CSM2-MR). Based on the trend equations, positive trends related to air temperature and precipitation variables are dominant. The trend magnitude shows the largest mean increase in all time series related to air temperature during the vegetation period. The highest mean precipitation increase occurs only in two time series. The Mann-Kendall statistics showed significantly positive trends in 11 cases and no changes in 9 cases. According to BCC-CSM2-MR, changes will be especially dominant in case of air temperatures. The expected changes in the total precipitation during the vegetation period show a tendency towards semiarid conditions. The presented results of observed and projected climate changes demand adaptation measures, especially from the aspect of sustainable agriculture

The analysis of annual and seasonal surface air temperature trends of southern and southeastern Bosnia and Herzegovina from 1961 to 2017

In some areas of the world, regional climate change is in good agreement with global climate change. This study brings new information about what defines climate change in the contact area of Adriatic Sea and Southeastern Europe, and conclusions are based on trend analysis of annual and seasonal temperatures in the southern and southeastern parts of Bosnia and Herzegovina. Trend analysis was applied on mean annual surface air temperatures, mean maximum temperatures, and mean minimum temperatures of all four seasons. This study used 4 meteorological stations: Livno, Bileća, Mostar, and Ivan Sedlo for 56 years. The main statistical method is the Mann-Kendall test. The total number of analysis is 48. A statistically significant positive trend was determined in 36 analysis, while in the rest of the tests this was not the case. The highest amount of temperature increase is present in the mean maximum summer air temperatures in Livno and Ivan Sedlo. Mean minimum autumn air temperatures had the smallest increase. Negative trend is present in the mean autumn surface air temperatures and mean maximum autumn temperatures. Using a geographical information system resulted in visualizing regional differences in the spatial distribution of isotherms. The study area has combined the influence of orography and maritime effects of the Adriatic Sea. Having in mind these results, the growing temperature has been recognized as a problem which needs more attention in Bosnia and Herzegovina. Unfortunately, official documents which propose economic adaptation on climate change in this country are not at a satisfactory level

The analysis of aridity in Central Serbia from 1949 to 2015

In this study, we apply De Martonne and Pinna combinative indices to analyze the aridity in Central Serbia. Our dataset consists of mean monthly surface air temperature (MMT) and mean monthly precipitation (MMP) for 26 meteorological stations during the period 1949-2015. MMT and MMP are used for calculating monthly, seasonal, and annual aridity indices for period of 66 years. According to the De Martonne climate classification, we determine five, three, and four types of climate on the monthly, seasonal, and annual basis, respectively. During the observed period, winter was extremely humid, spring and autumn were humid, and summer was semi-humid. Humid and semi-humid climate with Mediterranean vegetation are identified by the annual Pinna combinative index. We find that there is no change in aridity trend in Central Serbia for the period 1949-2015. Aridity indices are additionally compared with the North Atlantic Oscillation and El-Nino South Oscillation in order to establish a possible connection with the large-scale processes. Results are further compared with several earlier studies of aridity in Serbia. With this study, the analysis of aridity in whole Serbia has become complete