Gorica Stanojevic

Recent changes in Serbian climate extreme indices from 1961 to 2010

The evolution of daily extreme temperature and precipitation from 1961 to 2010 in Serbia was investigated. Trends of five temperature indices, three precipitation indices, and four combined indices were calculated at ten temperature and ten precipitation stations located within the study area, and their corresponding significances were tested using the Student’s t test. Obtained results suggest that the time periods of extremely hot weather last longer, while the periods of extremely cold weather are shortened. Trends of duration of extreme temperature conditions were most pronounced in summer season. Periods of mild weather conditions are extended. Amount and intensity of precipitation had statistically significant increase only during autumn and were most pronounced in the northern and western parts of the country. On an average, there was no significant decrease in the maximum number of consecutive dry days or increase in the wet days (except in autumn). The investigation of four combined temperature-precipitation regimes showed the domination of “dry” regimes over “wet,” increasing trend of “warm” regimes and decreasing trend of “cold” regimes. The correlation between the examined extreme indices and the large-scale circulation patterns showed that EA and NAO had significant influence on duration of winter warm periods, while their influence on duration of cold periods cannot be confirmed with certainty.

The impact of heat waves on daily mortality in Belgrade (Serbia) during summer

In this paper, we are dealing with two extreme events in temperature and population – heat wave and mortality. Our aim is to assess the relation between high temperatures and daily mortality counts during the summer months in the period 2000–2010 in Belgrade (Serbia). In order to establish this connection, we used Poisson regression and two different measures of heat wave: Warm Spell Duration Index (WSDI) and apparent temperature (T app). As mean daily temperature increases over 90th, 95th and 99th percentiles, average number of deaths increases for 15.3% (p < .01), 22.4% (p < .05) and 32.0% (insignificant for p < .1). We tested three different thresholds (90th, 95th, 99th) for WSDI and T app in order to separate the hottest heat-wave episodes. On average, mortality is higher than expected for 13.4%, 16.7% and 28.3% (90th, 95th and 99th percentiles for WSDI) and 16.1%, 17.3% and 32.5% (90th, 95th and 99th percentiles for T app). Estimated mortality excess with heat-wave indices is in accordance with regression output, meaning that WSDI and T app are good tools for heat-wave identification. During the most severe episode in July 2007, absolute temperature maximum (43.6°C) and daily maximum mortality counts (94 dead) were recorded in the same day (24 July 2007).

Does Belgrade (Serbia) need heat health warning system

Purpose – The purpose of this paper is to investigate whether is Belgrade (Serbia) suitable candidate for introduction of Heat Health Warning System (HHWS). Belgrade has high population density, considerable share of built up area and lot of multi floor buildings that are factors of heat-health vulnerability. Design/methodology/approach – The authors analyzed the impact of weather conditions on human health in Belgrade during the summer 2007 that was extremely warm in Southeastern Europe and Serbia. Daily cardiovascular, cerebrovascular and respiratory mortality counts were used in Poisson regression model with air temperature as predictor variable. Also, three different heat wave indices (Warm Spell Duration Index, apparent temperature and index based on daily minimum temperature) were tested in order to estimate their ability to capture episodes with mortality higher than expected. Findings – The temperature has the highest influence on cerebrovascular and cardiovascular mortality, while slightly modifi...

Recent changes in first and last frost dates and frost-free period in Serbia

ABSTRACT The study analyzes regional differences in the variability of time series of minimum temperatures during the spring and autumn, spatio-temporal variability of the last spring frost date and the first autumn frost date, as well as the length of the frost-free periods, in 15 stations in Serbia for the period 1961–2010. The analysis of trend in dates of frost occurrence over the study period showed that the last spring frost occurred earlier between 0.48 and 2.67 d decade−1, while changes in the first autumn frost occurrence were neither uniform nor statistically significant. Statistically significant earlier occurrence in the last spring frost at majority of stations starts in the mid-1980s, while significant later onset of the first autumn frost occurs in the second half of the 1990s The trend of the frost-free period displayed several distinct periods: (a) becomes shorter in the 1960s, (b) there is no trend in the1970s and (c) extends from the 1980s which is caused by early ending of the spring frost. The S-mode of Principal Component Analysis was applied in order to explore regional aspects of the minimum temperature variability during spring and autumn in Serbia. The influence of atmospheric circulation on observed temperature changes was analyzed using the teleconnection indices. The highest correlation was found for the minimum temperatures and the East Atlantic Oscillation in spring and autumn and for the East Atlantic/Western Russian Oscillation in autumn.

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]

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.