Vladan Ducic

Mapping average annual precipitation in Serbia (1961–1990) by using regression kriging

The appearence of geostatistics and geographical information systems has made it possible to analyze complex spatial patterns of meteorological elements over large areas in the applied climatology. The objective of this study is to use geostatistics to characterize the spatial structure and map the spatial variation of average values of precipitation for a 30-year period in Serbia. New, recently introduced, geostatistical algorithms facilitate utilization of auxiliary variables especially remote sensing data or freely available global datasets. The data from Advanced Spaceborn Thermal Emission and Reflection Radiometer global digital elevation model are incorporated as ancillary variables into spatial prediction of average annual precipitation using geostatistical method known as regression kriging. The R2 value of 0.842 proves high performance result of the prediction of the proposed method.

THE NORTH ATLANTIC OSCILLATION (NAO) AND THE WATER TEMPERATURE OF THE SAVA RIVER IN SERBIA

The data on the water temperature of the Sava in Serbia (hydrological stations Sabac and Belgrade, period 1961–2015) were used for the research, as well as the data on the surface air temperature. The temperature trends were determined and the significance (at p≤0.05 and p≤0.01) was established on the basis of the t-test. The Pearson correlation coefficient (R) was used for the calculation of the correlation. Increasing trends of the water temperature of the Sava were recorded in all cases at both stations. However, in the case of the HS Sabac, the trends for 6 months (February–April and September–November) were not statistically significant. In the case of the HS Belgrade, all the calculations (except for April) showed statistically significant increasing trends, which can be explained by anthropogenic influence. High level of correlation between the surface air temperature and the water temperature was also determined. In this research, the lowest values of R were recorded for October (0.561 for Belgrade), and on the seasonal level, for autumn (0.625 for Sabac). The research on the correlation between the water temperature of the Sava River and the NAO index showed the highest values of R for January (0.512 for HS Sabac and 0.528 for HS Belgrade). On the seasonal level, the highest values were recorded for winter (0.422 for HS Sabac and 0.432 for HS Belgrade).

FOREST FIRES IN PORTUGAL — THE CONNECTION WITH THE ATLANTIC MULTIDECADAL OSCILLATION (AMO)

The data on forest fires in Portugal in the period 1980–2015 were used in the research: the annual number of forest fires, the annual burned area and the average burned area per fire. Increasing trend of the annual number of forest fires (statistically significant at p≤0.01), non-significant increasing trend of the annual burned area and decreasing trend of the average burned area per fire (statistically significant at p≤0.01) were recorded. Portugal is the most endangered country by forest fires in comparison with the other European countries. During the research period, fires in Portugal covered 23.6% of the total burned area in five the most affected European countries (Portugal, Spain, France, Italy and Greece). In the research of the connection between forest fires and the Atlantic Multidecadal Oscillation (AMO) Pearson correlation coefficient (R) was used. Monthly, seasonal and annual values of the AMO index were used in calculations. All R values recorded for the annual number of fires were positive and statistically significant at p≤0.01. The highest values were recorded for August (0.543) and for summer (0.525). With the annual burned area all R values were also positive and the highest one on the seasonal level was for summer (0.359). With the average burned area per fire all R values were negative (−0.428 was recorded for winter). The results of the research could be applied in the fire danger forecast for periods of several months. Other climate indices should also be considered in future research.

CLIMATE REGIONALIZATION OF SERBIA ACCORDING TO KÖPPEN CLIMATE CLASSIFICATION

The paper presents a concise overview of the theoretical framework on which climate classifications are based. Beside short review of climate classifications, namely climatic regionalization for Serbia (or wider area including Serbia), main deficiency of these research was ascertained (which primarily relate to the period on the basis of which climate regionalization was carried out). The criteria of the Koppen climate classification are presented, on the basis of which the climate regionalization of Serbia has been carried out. The methodology of making maps of air temperatures and precipitation amounts has been described, on the basis of which a map of the climate regions of Serbia has been created. Spatial distribution of the types and subtypes of the climates in Serbia has been briefly described. It has been pointed to the constraints of the climate regionalization that arise from the theoretical bases of the climate classifications, but also from nature of the collected data and the applied methodology.

Tropical temperature altitude amplification in the hiatus period (1998-2012)

In the period 1998-2012 there was a stagnation in temperature rise, despite the GHGs radiation forcing is increased (hiatus period). According to Global Circulation Models simulations, expected response on the rise of GHGs forcing is tropical temperature altitude amplification - temperature increases faster in higher troposphere than in lower troposphere. In this paper, two satellite data sets, UAH MSU and RSS, were used to test altitude temperature amplification in tropic (20°N-20°S) in the hiatus period. We compared data from satellite data sets from lower troposphere (TLT) and middle troposphere (TMT) in general and particularly for land and ocean (for UAH MSU). The results from both satellite measurements showed the presence of hiatus, i.e. slowdown of the temperature rise in the period 1998-2012 compared to period 1979-2012 (UAH MSU) and temperature fall for RSS data. Smaller increase, i.e. temperature fall over ocean showed that hiatus is an ocean phenomenon above all. Data for UAH MSU showed that temperature altitude amplification in tropic was not present either for period 1979-2012, or 1998-2012. RSS data set also do not show temperature altitude amplification either for longer (1979-2012), or for shorter period (1998-2012). RSS data for successive 15-year periods from 1979-1993 till 1998-2012 does not show tropical temperature altitude amplification and in one case negative trend is registered in TLT and in two cases in TMT. In general, our results do not show presence of temperature altitude amplification in tropic in the hiatus period. [Projekat Ministarstva nauke Republike Srbije, br. III47007]

Assessment on Temperature Extremes in Montenegro

Montenegro so far has been poorly investigated in terms of climate extremes. The aim of this paper was analysis of extreme temperature indices in the Mediterranean region of Montenegro for the period 1951–2010. Four stations in the coastal area of Montenegro have been analysed Herceg Novi, Ulcinj, Budva and Bar. Due to well known great climate shift occurred in the late 1970 two periods (before 1980 and after 1980) were separately investigated. Six ETCCD indices of temperature extremes have been chosen. Indices and their trends are calculated on annual scale in order to identify possible temperature changes over the coastal region of Montenegro. The trend was analysed using Man-Kendall non parametric test while the slope is estimated using Sen’s slope estimator.

The changes of precipitation in Podgorica for period 1951-2010

The global warming and climate change are the actual and challenging topics. Recently there is one question, frequently asked: whether todays climate is changing? The studies of this issues are mainly related to the two the most important climatic elements - air temperature and precipitation amounts. We have done research about temperature variability for Montenegro and the main aim of this paper is analysis precipitation changes for station Podgorica (Montenegro) in the period of sistematic observation - are there changes, to what extent and whether they are significant. According to the results, acumulated precipitation do not show significant changes for annual and seasonal values in the period 1951-2010. The interannual variations of the precipitation (which are characterictic for this climate element) do not show increases in recent times. The component trend shows some changes, but statisticaly insignigficant. The previous results for precipitation conditions in Podgorica are not in accordance with the concept of Intergovermental Panel on Climate Change (IPCC) which predicted a general decerease in precipitation and increase variability on this area.