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Papers by Adrian Piticar
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
International Journal of Environmental Research and Public Health, 2020
Various environmental factors influence the outbreak and spread of epidemic or even pandemic even... more Various environmental factors influence the outbreak and spread of epidemic or even pandemic events which, in turn, may cause feedbacks on the environment. The novel coronavirus disease (COVID-19) was declared a pandemic on 13 March 2020 and its rapid onset, spatial extent and complex consequences make it a once-in-a-century global disaster. Most countries responded by social distancing measures and severely diminished economic and other activities. Consequently, by the end of April 2020, the COVID-19 pandemic has led to numerous environmental impacts, both positive such as enhanced air and water quality in urban areas, and negative, such as shoreline pollution due to the disposal of sanitary consumables. This study presents an early overview of the observed and potential impacts of the COVID-19 on the environment. We argue that the effects of COVID-19 are determined mainly by anthropogenic factors which are becoming obvious as human activity diminishes across the planet, and the impacts on cities and public health will be continued in the coming years.
Boletín de la Asociación de Geógrafos Españoles, 2018
This study includes a diagnostic and evolutive analysis of the bioclimate of Republic of Mo... more This study includes a diagnostic and evolutive analysis of the bioclimate of Republic of Moldova, made by using the Wind Chill (WCI) and Cooling Power (CP) indices. The bioclimate of the cold season (October–March) had, in the time period 1960–2012), a warming trend, highlighted by the decrease of WCI values. During the warm season, the bioclimate of Republic of Moldova recorded a gradual warming, highlighted by the decrease in CP index values. The CP index values were analyzed in relation to those of the Tourism Climate Index (TCI), useful for planning the tourist activities of any kind. The actual values of TCI and the ones anticipated for the future indicate, for the Republic of Moldova, an increasing bioclimate favorability for all forms and types of tourism.
Agricultural Systems, 2020
The impact of climate change on agricultural systems has become a reality that currently threaten... more The impact of climate change on agricultural systems has become a reality that currently threatens food security in numerous regions worldwide. However, concrete consequences of climate change on agricultural yields still remain unknown in many countries around the world, including Romania. This study conducts a first-ever analysis of the impact of climate change on maize productivity in Romania, the European Union's leader in maize harvested production, which holds almost 30% of the European maize production. The paper explores complex statistical relationships between the climatic water balance (CWB)/its constituting parameters precipitation (P) and reference evapotranspiration (ETo) and maize yields (Zea mays L.) recorded nationally from 1990 to 2013, a key-period in Romania in terms of climate and socio-political changes. The analysis of various agro-climatic data, based on well-established methods (linear regression and bootstrapping), showed that the countrywide dependence of maize yields variability to changes in the analyzed climatic variables was considerable and reached peak values of roughly 60% for the CWB-yield relationship and around 50% for the P-yield and ETo-yield relationships. At the same time, a significant sensitivity of maize yield dynamics was found in response to a 1-unit climate change, which, on average, was quantified at 5 kg/ha/yr for a 1-mm variation of the CWB, and at 19 kg/ha/yr and 11 kg/ha/yr for a 1-mm change in P and ETo, respectively. In addition to this agricultural impact, our findings regarding the economic impact associated to concrete climatic trends (CWB decreases and ETo increases over the 24 years, consistent with an overall increase of the humidity deficit, and P increases, consistent with humidity surplus) indicate total costs of approximately 53 mil € (or almost 1% of the national agricultural gross domestic product) for the CWB-yield relationship, and of~200 mil € (~3%) for ETo-yield. It was found that the separate influence of P in maize dynamics was positive, with net financial gains of up to~130 mil € (~2%). However, our findings show that only the economic costs associated with the impact of ETo on maize productivity are highly statistically reliable. Our results issue a warning about the urgent measures to fight climate change effects on agriculture in Romania, which are necessary especially in the counties located in the Extra-Carpathian regions, highly vulnerable to climate dynamics.
Forum Geografic, 2019
Heat waves (HWs) represent a major danger to society and natural environment. The increasing occu... more Heat waves (HWs) represent a major danger to society and natural environment. The increasing occurrence of high magnitude and impact HWs has raised concerns worldwide and has attracted an increasing interest on this issue among climatologists over the past decade. In this review the research from 2007-2018 period on HWs definitions, driving mechanisms, present changes, future changes, and impact on human mortality is summarized. By reviewing the recent literature, it was found that whilst the atmospheric dynamic is considered to be the primary driver in HW occurrence, the sea surface temperature (SST) and land surface conditions are also essential driving components. The vastness of HW-definitions raises difficulties in selecting the appropriate methodology to identify heat episodes and to compare results from studies which used different definitions. However, by analyzing a sample of 109 papers, a preference for percentile-based definitions was observed. Therefore, 71.6% of the analyzed articles used only percentile-based definitions to identify HWs. Despite the wide variety of definitions, the analysis of changes in HWs converged to similar results. Thus, the existing recent literature provided extensive evidence of significant increase in HWs characteristics across large regions of the planet. Available scientific literature indicated that HWs have been responsible for a considerable increase in mortality in many regions of the world. In the future HWs are predicted to increase in their main characteristics leading to a greater impact on human mortality. Nevertheless, the implementation of rigorous adaptation measures can mitigate the negative impact on mortality. In conclusion, it was noted that a substantial progress has been done in the HW research, but there are still important gaps in this issue which need to be addressed. Rezumat. O revizuire a studiilor recente privind definițiile, mecanismele, schimbările undelor de căldură și impactul asupra mortalității Valurile de căldură (HWs) reprezintă un pericol major pentru societate și mediul înconjurător. Creșterea frecvenței HWs cu magnitudine și impact ridicate a generat preocupare la nivel global și a atras interes asupra problemei în rândul climatologilor în ultimul deceniu. În articol sunt inventariate studiile realizate în perioada 2007-2018 privind definiţiile HWs, factorilor declanșatori, schimbărilor prezente și viitoare și impactul asupra mortalității. Prin inventarierea literaturii de specialitate recente, a fost evdențiat că deși dinamica atmosferei este principalul factor generator al HWs, temperatura apei de suprafață (SST) și condițiile date de suprafața terenurilor sunt de asemenea factori generatori importanți. Diverstatea definițiilor atribuite HWs determină dificultăți în selectarea unor metodologii potrivite pentru identificarea fenomenelor respectve și compararea rezultatelor unor studii care utilizează definiții diferite. Totuși, analizând un eșantion de 109 lucrări, a fost observată o preferință asupra unor definiții bazate pe percentile. Așadar, în 71.6% din articolele analizate au fost utilizate doar definiții bazate pe percentile pentru identificarea HWs. În ciuda marii varietăți de definiții, rezultatele analizelor au fost similare. Astfel, literatura recentă furnizează dovezi ample care atestă o creștere semnificativă a caracteristicilor HWs pe suprafeţe extinse ale planetei. Literatura științifică indică faptul că HWs au fost unul dintre factorii responsabili pentru creșterea mortalității în multe părți ale lume. În viitor este anticipată o amplificare a caracteristicilor HWs, conducând la o creștere a impactului pe care acestea îl vor avea asupra mortalității. Cu toate acestea, prin implementarea unor măsuri riguroase de adaptare, poate fi diminuat impactul negativ care conduce la mortalitate. În concluzie, a fost remarcat faptul că s-a realizat un progres substanţial în cercetarea HWs, rămânând însă lacune importante care necesită abordare. Cuvinte-cheie: schimbări climatice, temperaturi extreme, val de căldură, factorul excesului de căldură
International Journal of Biometeorology, 2019
Climate change has profound environmental and socio-economic implications. To analyze climate cha... more Climate change has profound environmental and socio-economic implications. To analyze climate change in relation to crops, a wide variety of agro-climatic indices has been proposed by the scientific community. In this study, changes in a set of 12 agro-climatic indices related to temperature were investigated in Central Chile over a 56-year period (1961–2016). The indices were computed based on data referring to daily maximum and minimum temperatures (TX and TN). They were organized in two categories: (1) cold- and (2) heat-related indices. Cold-related indices consisted of first frost day (FFD), last frost day (LFD), frost period (FP), number of frost days (FD), accumulated frost (AF), and number of days when TN is below − 2 °C (FD-2). Heat related indices included the growing degree day (GDD) index, calculated based on four thresholds which measure the available heat resources for a wide variety of plants with different thermal requirements, and two heat stress indices which quantify the number of days with TX above 25 °C (plant heat stress (PHS)) and above 30 °C (plant high heat stress (PHHS)). Changes in agroclimatic indices were investigated using the Mann–Kendall test and the Sen’s slope estimator. The main results revealed that the FFD occurred later, while LFD occurred earlier, thus determining a shortening of the FP in the northern half of the studied area. Trends in FD, AF, and FD-2 indices generally indicated warmer conditions in terms of TN during the cold period of the year. Agro-climatic indices related to heat showed important changes in Central Chile. Thus, statistically, the majority of trends become significant and indicated enhanced condition for crops in respect of GDD indices. However, from the heat stress perspective, the analyzed indices showed that conditions become worse in most of the studied locations for crops sensible to temperatures higher than 25 and 30 °C.
Changes in precipitation (P), evapotranspiration (ET) and, implicitly, in the climatic water bala... more Changes in precipitation (P), evapotranspiration (ET) and, implicitly, in the climatic water balance (CWB), are imminent effects of climate warming. However, changes in the CWB, as a response to changes in P and ET, have not yet been analysed thoroughly enough in many parts of the world, including Romania. The present study explores the spatio-temporal changes of the CWB (difference between P and reference evapotranspiration, ET o) in Romania, based on a wide range of climatic data (P, as well as temperature, relative air humidity, sunshine duration and wind speed, necessary for computing ET o with the FAO-56 Penman-Monteith method) recorded at 70 weather stations across the country in the 1961–2013 period. As a secondary objective, the study attempts to identify the possible connections between the index's trends and large-scale atmospheric circulation, assessed based on the dynamics of certain European-scale relevant teleconnection indices. Thus, the Mann–Kendall test and Sen's slope methods were used to analyse CWB trends (but also P and ET o trends, in order to explain CWB pattern changes) annually, seasonally and in the maize and wheat growing seasons. Also, the Spearman correlation procedure and a composite analysis between interannual series of teleconnection indices and CWB were used to assess the influence of atmospheric circulation on the index's variability for all analysed time scales. The results generally showed CWB decreases (for the most part of up to −2 mm/yr, yet with a relatively low statistical significance) and highlighted an overall amplification of drier conditions on all time scales, except for autumn (CWB increases, generally of up to 1 mm/yr, but with low statistical significance). Moreover, net changes of even under −200 mm/53 yrs annually and −175 mm/53 yrs in summer and for the maize and wheat growing seasons were found in the CWB. Spatially, it was found that the country's southwestern and southeastern regions are the main epicentres of drier trends, while the northwest appears to have become wetter. Overall, the negative CWB trends are due to partial P decreases (statistically insignificant) and general ET o increases (highly statistically significant, even 100% in summer). It seems that the amplification of the climatic water deficit across the country is especially linked to the positive phases of the Arctic Oscillation and North Atlantic Oscillation, but also, in part, to those of several other teleconnection indices that affect Europe. Our results signal the necessity to adapt anthropic and ecological systems to future dryness trends countrywide, which will most likely intensify against the background of climate change expected to occur by the end of the century.
This research aims to examine changes in heat waves (HWs) over Chile from 1961 to 2016 using dail... more This research aims to examine changes in heat waves (HWs) over Chile from 1961 to 2016 using daily maximum (TX) and minimum temperature (TN) data recorded at 13 weather stations. Based on three HW-definitions and five aspects for each definition some 15 indices were calculated and analyzed for the extended summer period (November-March). The three definitions of the HWs employed in this study were based on: (1) the TX exceeding the 90th percentile for at least three consecutive days, (2) the TN exceeding the 90th percentile for at least three consecutive days, and (3) the positive values of excess heat factor (EHF) maintaining for at least three consecutive days. The five aspects calculated for each of the definitions provided information related to the frequency , duration, and intensity of HWs. Trends (be them increasing or decreasing), magnitude (change per decade) and statistical significance (p < 0.05) were identified using the ordinary least square method and the t-test. Therefore, in terms of HW aspects, the results of the HWs climate regime analysis showed that the most extreme region of Chile is the Atacama Desert, followed by the Santiago metropolitan area. Change analysis revealed that Chile experienced increasing trends in most of the HW data sets. Thus, the frequency of trend types of all HW indices time series showed an increasing trend of 79%. About 24% of the time series showed statistically significant increasing trends. Decreasing trends were found in about 20% of the analyzed data, less than 1% of which being statistically significant. Stationary trends were detected in only 2% of the series. The highest frequency of statistically significant increasing trends was found in the HWs identified based on TX, followed by those computed based on EHF. Regarding their aspects, the number of events had the highest frequency of significant increasing trends. In terms of spatial distribution, the most important changes were found in central Chile.
In this paper, we investigated changes in heat and cold waves in Romania over the period 1961–201... more In this paper, we investigated changes in heat and cold waves in Romania over the period 1961–2015 by employing a new and superior approach. It consists in using excess heat factor to identify heat waves and excess cold factor to identify cold waves. Five indices were calculated and then analysed for both heat waves and cold waves resulting in a set of ten indices. Indices for heat waves were analysed for the extended summer season (May–September), whereas those for cold waves were assessed for the extended winter (November–March). The intensity threshold was set to be equal or above the 90th percentile for heat waves, and equal or below the 10th percentile for cold waves, while the duration threshold for both heat and cold waves was of at least three consecutive days. For a better comparison with other studies conducted worldwide, and to get more information from the data sets, the percentile thresholds for heat and cold waves identification were calculated based on three reference periods: 1961–1990, 1971–2000, and 1981–2010. Trends were calculated using ordinary least square method, whereas statistical significance was assessed by the t-test. The main results indicated that changes are more substantial in the case of indices calculated based on excess heat factor compared to those based on excess cold factor, suggesting that the warming process is more reflected in heat waves rather than in cold waves. Thus, heat waves became more frequent, longer, and more intense, while cold waves became less frequent, but more intense. When the reference period for percentile threshold calculation was changed from the earliest to the most recent ones, the frequency of increasing and significant increasing trends decreased for some of the heat wave indices, while for the cold wave indices the significant downward trends increased.
In this paper, we investigated changes in heat and cold waves in Romania over the period 1961-201... more In this paper, we investigated changes in heat and cold waves in Romania over the period 1961-2015 by employing a new and superior approach. It consists in using excess heat factor to identify heat waves and excess cold factor to identify cold waves. Five indices were calculated and then analysed for both heat waves and cold waves resulting in a set of ten indices. Indices for heat waves were analysed for the extended summer season (May-September), whereas those for cold waves were assessed for the extended winter (November-March). The intensity threshold was set to be equal or above the 90th percentile for heat waves, and equal or below the 10th percentile for cold waves, while the duration threshold for both heat and cold waves was of at least three consecutive days. For a better comparison with other studies conducted worldwide, and to get more information from the data sets, the percentile thresholds for heat and cold waves identification were calculated based on three reference periods: 1961-1990, 1971-2000, and 1981-2010. Trends were calculated using ordinary least square method, whereas statistical significance was assessed by the t-test. The main results indicated that changes are more substantial in the case of indices calculated based on excess heat factor compared to those based on excess cold factor, suggesting that the warming process is more reflected in heat waves rather than in cold waves. Thus, heat waves became more frequent, longer, and more intense, while cold waves became less frequent, but more intense. When the reference period for percentile threshold calculation was changed from the earliest to the most recent ones, the frequency of increasing and significant increasing trends decreased for some of the heat wave indices, while for the cold wave indices the significant downward trends increased.
Theoretical and Applied Climatology, 2015
The main objectives of this study are to investigate the spatial distribution and changes in refe... more The main objectives of this study are to investigate the spatial distribution and changes in reference evapotranspiration (ET 0 ) in the Republic of Moldova. Monthly data of maximum and minimum air temperature, sunshine duration, relative humidity, and wind speed recorded at 14 weather stations over a period of 52 years (1961-2012) were used. ET 0 was computed based on the FAO Penman-Monteith formula. Annual and growing seasons of winter wheat and maize time series were analyzed for the 1981-2012 period as well as for the [1961][1962][1963][1964][1965][1966][1967][1968][1969][1970][1971][1972][1973][1974][1975][1976][1977][1978][1979][1980]. The trends and their statistical significance in ET 0 series were detected using Mann-Kendall test and T test, while the magnitude of the trends was estimated using Sen's slope and linear regression. For the 1981-2012 period, the results indicated that annual ET 0 had a positive trend in more than 90 % of the time series according to both parametric and nonparametric methods. The magnitude of positive trends in annual ET 0 series ranged between 13.80 and 72.07 mm/decade. In the growing seasons of winter wheat and maize, the results are similar to those found in the annual series. Significant decreasing trends dominated over the 1961-1980 period.
Global and Planetary Change, 2016
In the last two decades many climate change studies have focused on extreme temperatures as they ... more In the last two decades many climate change studies have focused on extreme temperatures as they have a significant impact on environment and society. Among the weather events generated by extreme temperatures, heat waves are some of the most harmful. The main objective of this study was to detect and analyze changes in heat waves in Romania based on daily observation data (maximum and minimum temperature) over the extended summer period (May–Sept) using a set of 10 indices and to explore the spatial patterns of changes. Heat wave data series were derived from daily maximum and minimum temperature data sets recorded in 29 weather stations across Romania over a 55-year period (1961–2015). In this study, the threshold chosen was the 90th per-centile calculated based on a 15-day window centered on each calendar day, and for three baseline periods (1961–1990, 1971–2000, and 1981–2010). Two heat wave definitions were considered: at least three consecutive days when maximum temperature exceeds 90th percentile, and at least three consecutive days when minimum temperature exceeds 90th percentile. For each of them, five variables were calculated: amplitude, magnitude, number of events, duration, and frequency. Finally, 10 indices resulted for further analysis. The main results are: most of the indices have statistically significant increasing trends; only one index for one weather station indicated statistically significant decreasing trend; the changes are more intense in case of heat waves detected based on maximum temperature compared to those obtained for heat waves identified based on minimum temperature; western and central regions of Romania are the most exposed to increasing heat waves.
Global and Planetary Change, 2013
In the last few decades, climate changes have become the most important topic in the field of cli... more In the last few decades, climate changes have become the most important topic in the field of climatology. Reference evapotranspiration (ET 0 ) is often used to identify regions prone to drought or aridity. In this paper, we used monthly data recorded in 57 weather stations in Romania over the period 1961-2007. The FAO Penman-Monteith method, based on air temperature, sunshine duration, relative humidity and wind speed, was employed in order to calculate ET 0 . Seasonal, annual, winter wheat and maize growing seasons data sets of ET 0 were generated. The trends were detected using the Mann-Kendall test and Sen's slope, while an ArcGIS software was employed for mapping the results. The main findings of the study are: positive slopes were found in 71% of the data series considered and almost 30% of the total number of series were found significant at α = 0.05; the highest frequency of the increasing trends as well as their absolute maximum magnitude were detected during summer and maize growing season; in winter, significant increasing changes are specific mainly to the extra-Carpathians regions; in autumn decreasing ET 0 is specific to more than 80% of the locations, but the significant decrease characterizes mainly the southern half of the country; during the growing seasons of maize and winter wheat, the increase of the ET 0 is dominant for the entire country. The relative change decreases with the increase of the length of the period considered: the most intense changes were detected for climatic seasons, followed by crop growing seasons and annual values. Among the climatic seasons, the highest relative increase is specific to winter followed by summer, spring and autumn, while for the crop growing seasons the values detected are similar.
International Journal of Climatology, 2013
Changes in daily extreme temperatures have been identified in many studies conducted at local, re... more Changes in daily extreme temperatures have been identified in many studies conducted at local, regional or global scales. For Romanian territory, only little research on this issue was done. In this article, the extra-Carpathians regions of Romania located southward and eastward from the Carpathians Chain were considered. This study is focused on analyzing daily extreme temperature trends at a regional scale (eastern, southern and southeastern regions of Romania) across 50 years . Data sets of daily minimum and maximum temperature recorded in 14 weather stations were analyzed. The main goal was to find changes in extreme daily temperatures using a set of 20 indices adopted from the core indices developed by ETCCDMI with appropriate modifications to suit to the analyzed territory. The main results suggest that regional temperature trends at the scale of extra-Carpathians areas of Romania are similar to those calculated for global and European continental scales; the climate has become warmer during the last decades. It has been identified that both extreme daily maximum and minimum temperatures have increased in the analyzed areas. For all the indices related to hot temperature most trends are significantly positive. The strongest increase was detected for hot related extremes such as summer days and tropical nights as well as for maximum values of maximum and minimum daily temperatures. For indices related to cold there are different sign slopes, but negative slopes prevail, especially for number of days under a defined threshold. This is also an evidence of the important warming in the area. Generally, it was found that the daily maximum temperature is getting more extreme, whereas the minimum is getting less extreme. Copyright 2012 Royal Meteorological Society KEY WORDS daily extreme temperature indices; daily maximum and minimum temperatures; trend; Mann-Kendall test and Sen's slope; extra-Carpathians areas of Romania
14th SGEM GeoConference on ENERGY AND CLEAN TECHNOLOGIES, 2014
Changes in daily extremes events is one of the most important topic in climate literature and man... more Changes in daily extremes events is one of the most important topic in climate literature and many studies have been conducted so far at local or regional scale worldwide. For the Romanian territory, only little research on this issue was done. In this article, the Carpathian and intra-Carpathians regions of Romania were considered. This study is focused on analyzing the trends of daily extreme temperature indices at a regional scale over a period of 50 years: 1961-2010. Data sets of daily minimum and maximum temperature recorded in 10 weather stations were analyzed. The main goal was to find changes in daily extreme temperatures by using a set of 9 indices adopted from the core indices developed by ETCCDMI with appropriate modifications to suit to the analyzed territory. The main results suggest that the climate has become warmer during the last decades. Trends of extreme temperature indices at the regional scale of Carpathians and intra-Carpathians areas are increasing for most of the indices calculated. It has been identified that both extreme daily maximum and minimum temperatures indices have increased in the analyzed areas. For all the indices related to hot temperature most trends are statistically significant.
Quaternary International, 2015
ABSTRACT Changes in daily extreme precipitation have been identified in many studies conducted at... more ABSTRACT Changes in daily extreme precipitation have been identified in many studies conducted at local, regional, or global scales. In Romania, little research on this issue has been done. The present study focuses on the analysis of the trends in daily extreme precipitation indices over a period of 53 years (1961–2013). Data sets of daily precipitation recorded in 34 weather stations were analyzed. Among them, three are located in the Carpathians and four on the Black Sea Coast. The main goal was to find out changes in extreme daily precipitation using a set of 13 indices adopted from the core indices developed by ETCCDMI adapted to suit to the studied area. The series of indices and their trends were generated using RClimDex software. The trends have been calculated by employing modified Mann–Kendall test and Sen's slope. Generally, the climate of Romania has become wetter over the 53-yr period considered, especially in the northern regions, although the spatial distribution of the significant trend slopes in the area is extremely irregular. Based on fixed threshold indices analysis, extreme precipitation events are characterized by a decreasing in the total number of precipitation days (R0.1), and a dominant increasing trend for the number of isolated days with moderate and heavy precipitation (R5, R10).
Changes in daily extremes events is one of the most important topic in climate literature and man... more Changes in daily extremes events is one of the most important topic in climate literature and many studies have been conducted so far at local or regional scale worldwide. For the Romanian territory, only little research on this issue was done. In this article, the Carpathian and intra-Carpathians regions of Romania were considered. This study is focused on analyzing the trends of daily extreme temperature indices at a regional scale over a period of 50 years: 1961–2010. Data sets of daily minimum and maximum temperature recorded in 10 weather stations were analyzed. The main goal was to find changes in daily extreme temperatures by using a set of 9 indices adopted from the core indices developed by ETCCDMI with appropriate modifications to suit to the analyzed territory. The main results suggest that the climate has become warmer during the last decades. Trends of extreme temperature indices at the regional scale of Carpathians and intra-Carpathians areas are increasing for most of the indices calculated. It has been identified that both extreme daily maximum and minimum temperatures indices have increased in the analyzed areas. For all the indices related to hot temperature most trends are statistically significant.
Changes in daily extreme precipitation have been identified in many studies conducted at local, r... more Changes in daily extreme precipitation have been identified in many studies conducted at local, regional,
or global scales. In Romania, little research on this issue has been done. The present study focuses on the
analysis of the trends in daily extreme precipitation indices over a period of 53 years (1961e2013). Data
sets of daily precipitation recorded in 34 weather stations were analyzed. Among them, three are located
in the Carpathians and four on the Black Sea Coast. The main goal was to find out changes in extreme
daily precipitation using a set of 13 indices adopted from the core indices developed by ETCCDMI
adapted to suit to the studied area. The series of indices and their trends were generated using RClimDex
software. The trends have been calculated by employing modified ManneKendall test and Sen's slope.
Generally, the climate of Romania has become wetter over the 53-yr period considered, especially in the
northern regions, although the spatial distribution of the significant trend slopes in the area is extremely
irregular. Based on fixed threshold indices analysis, extreme precipitation events are characterized by a
decreasing in the total number of precipitation days (R0.1), and a dominant increasing trend for the
number of isolated days with moderate and heavy precipitation (R5, R10).
The main objectives of this study are to investigate the spatial distribution and changes in refe... more The main objectives of this study are to investigate the spatial distribution and changes in reference evapotranspiration (ET0) in the Republic of Moldova. Monthly data of maximum and minimum air temperature, sunshine duration, relative humidity, and wind speed recorded at 14 weather stations over a period of 52 years (1961–2012) were used. ET0 was computed based on the FAO Penman-Monteith formula. Annual and growing seasons of winter wheat and maize time series were analyzed for the 1981–2012 period as well as for the 1961–1980. The trends and their statistical significance in ET0 series were detected using Mann-Kendall test and T test, while the magnitude of the trends was estimated using Sen’s slope and linear regression. For the 1981–2012 period, the results indicated that annual ET0 had a positive trend in more than 90 % of the time series according to both parametric and nonparametric methods. The magnitude of positive trends in annual ET0 series ranged between 13.80 and 72.07 mm/decade. In the growing seasons of winter wheat and maize, the results are similar to those found in the annual series. Significant decreasing trends dominated over the 1961–1980 period.
Global and Planetary Change, 2013
In the last few decades, climate changes have become the most important topic in the field of cli... more In the last few decades, climate changes have become the most important topic in the field of climatology. Reference evapotranspiration (ET0) is often used to identify regions prone to drought or aridity. In this paper, we used monthly data recorded in 57weather stations in Romania over the period 1961–2007. The FAO Penman–Monteith method, based on air temperature, sunshine duration, relative humidity andwind speed,was employed in order to calculate ET0. Seasonal, annual, winter wheat and maize growing seasons data sets of ET0 were generated. The trends were detected using the Mann–Kendall test and Sen's slope, while an ArcGIS software was employed for mapping the results. The main findings of the study are: positive slopes were found in 71% of the data series considered and almost 30% of the total number of series were found significant at α = 0.05; the highest frequency of the increasing trends as well as their absolute maximum magnitude were detected during summer and maize growing season; in winter, significant increasing changes are specific mainly to the extra-Carpathians regions; in autumn decreasing ET0 is specific to more than 80% of the locations, but the significant decrease characterizes mainly the southern half of the country; during the growing seasons of maize and winter wheat, the increase of the ET0 is dominant for the entire country. The relative change decreases with the increase of the length of the period considered: the most intense changes were detected for climatic seasons, followed by crop growing seasons and annual values. Among the climatic seasons, the highest relative increase is specific to winter followed by summer, spring and autumn, while for the crop growing seasons the values detected are similar.
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
International Journal of Environmental Research and Public Health, 2020
Various environmental factors influence the outbreak and spread of epidemic or even pandemic even... more Various environmental factors influence the outbreak and spread of epidemic or even pandemic events which, in turn, may cause feedbacks on the environment. The novel coronavirus disease (COVID-19) was declared a pandemic on 13 March 2020 and its rapid onset, spatial extent and complex consequences make it a once-in-a-century global disaster. Most countries responded by social distancing measures and severely diminished economic and other activities. Consequently, by the end of April 2020, the COVID-19 pandemic has led to numerous environmental impacts, both positive such as enhanced air and water quality in urban areas, and negative, such as shoreline pollution due to the disposal of sanitary consumables. This study presents an early overview of the observed and potential impacts of the COVID-19 on the environment. We argue that the effects of COVID-19 are determined mainly by anthropogenic factors which are becoming obvious as human activity diminishes across the planet, and the impacts on cities and public health will be continued in the coming years.
Boletín de la Asociación de Geógrafos Españoles, 2018
This study includes a diagnostic and evolutive analysis of the bioclimate of Republic of Mo... more This study includes a diagnostic and evolutive analysis of the bioclimate of Republic of Moldova, made by using the Wind Chill (WCI) and Cooling Power (CP) indices. The bioclimate of the cold season (October–March) had, in the time period 1960–2012), a warming trend, highlighted by the decrease of WCI values. During the warm season, the bioclimate of Republic of Moldova recorded a gradual warming, highlighted by the decrease in CP index values. The CP index values were analyzed in relation to those of the Tourism Climate Index (TCI), useful for planning the tourist activities of any kind. The actual values of TCI and the ones anticipated for the future indicate, for the Republic of Moldova, an increasing bioclimate favorability for all forms and types of tourism.
Agricultural Systems, 2020
The impact of climate change on agricultural systems has become a reality that currently threaten... more The impact of climate change on agricultural systems has become a reality that currently threatens food security in numerous regions worldwide. However, concrete consequences of climate change on agricultural yields still remain unknown in many countries around the world, including Romania. This study conducts a first-ever analysis of the impact of climate change on maize productivity in Romania, the European Union's leader in maize harvested production, which holds almost 30% of the European maize production. The paper explores complex statistical relationships between the climatic water balance (CWB)/its constituting parameters precipitation (P) and reference evapotranspiration (ETo) and maize yields (Zea mays L.) recorded nationally from 1990 to 2013, a key-period in Romania in terms of climate and socio-political changes. The analysis of various agro-climatic data, based on well-established methods (linear regression and bootstrapping), showed that the countrywide dependence of maize yields variability to changes in the analyzed climatic variables was considerable and reached peak values of roughly 60% for the CWB-yield relationship and around 50% for the P-yield and ETo-yield relationships. At the same time, a significant sensitivity of maize yield dynamics was found in response to a 1-unit climate change, which, on average, was quantified at 5 kg/ha/yr for a 1-mm variation of the CWB, and at 19 kg/ha/yr and 11 kg/ha/yr for a 1-mm change in P and ETo, respectively. In addition to this agricultural impact, our findings regarding the economic impact associated to concrete climatic trends (CWB decreases and ETo increases over the 24 years, consistent with an overall increase of the humidity deficit, and P increases, consistent with humidity surplus) indicate total costs of approximately 53 mil € (or almost 1% of the national agricultural gross domestic product) for the CWB-yield relationship, and of~200 mil € (~3%) for ETo-yield. It was found that the separate influence of P in maize dynamics was positive, with net financial gains of up to~130 mil € (~2%). However, our findings show that only the economic costs associated with the impact of ETo on maize productivity are highly statistically reliable. Our results issue a warning about the urgent measures to fight climate change effects on agriculture in Romania, which are necessary especially in the counties located in the Extra-Carpathian regions, highly vulnerable to climate dynamics.
Forum Geografic, 2019
Heat waves (HWs) represent a major danger to society and natural environment. The increasing occu... more Heat waves (HWs) represent a major danger to society and natural environment. The increasing occurrence of high magnitude and impact HWs has raised concerns worldwide and has attracted an increasing interest on this issue among climatologists over the past decade. In this review the research from 2007-2018 period on HWs definitions, driving mechanisms, present changes, future changes, and impact on human mortality is summarized. By reviewing the recent literature, it was found that whilst the atmospheric dynamic is considered to be the primary driver in HW occurrence, the sea surface temperature (SST) and land surface conditions are also essential driving components. The vastness of HW-definitions raises difficulties in selecting the appropriate methodology to identify heat episodes and to compare results from studies which used different definitions. However, by analyzing a sample of 109 papers, a preference for percentile-based definitions was observed. Therefore, 71.6% of the analyzed articles used only percentile-based definitions to identify HWs. Despite the wide variety of definitions, the analysis of changes in HWs converged to similar results. Thus, the existing recent literature provided extensive evidence of significant increase in HWs characteristics across large regions of the planet. Available scientific literature indicated that HWs have been responsible for a considerable increase in mortality in many regions of the world. In the future HWs are predicted to increase in their main characteristics leading to a greater impact on human mortality. Nevertheless, the implementation of rigorous adaptation measures can mitigate the negative impact on mortality. In conclusion, it was noted that a substantial progress has been done in the HW research, but there are still important gaps in this issue which need to be addressed. Rezumat. O revizuire a studiilor recente privind definițiile, mecanismele, schimbările undelor de căldură și impactul asupra mortalității Valurile de căldură (HWs) reprezintă un pericol major pentru societate și mediul înconjurător. Creșterea frecvenței HWs cu magnitudine și impact ridicate a generat preocupare la nivel global și a atras interes asupra problemei în rândul climatologilor în ultimul deceniu. În articol sunt inventariate studiile realizate în perioada 2007-2018 privind definiţiile HWs, factorilor declanșatori, schimbărilor prezente și viitoare și impactul asupra mortalității. Prin inventarierea literaturii de specialitate recente, a fost evdențiat că deși dinamica atmosferei este principalul factor generator al HWs, temperatura apei de suprafață (SST) și condițiile date de suprafața terenurilor sunt de asemenea factori generatori importanți. Diverstatea definițiilor atribuite HWs determină dificultăți în selectarea unor metodologii potrivite pentru identificarea fenomenelor respectve și compararea rezultatelor unor studii care utilizează definiții diferite. Totuși, analizând un eșantion de 109 lucrări, a fost observată o preferință asupra unor definiții bazate pe percentile. Așadar, în 71.6% din articolele analizate au fost utilizate doar definiții bazate pe percentile pentru identificarea HWs. În ciuda marii varietăți de definiții, rezultatele analizelor au fost similare. Astfel, literatura recentă furnizează dovezi ample care atestă o creștere semnificativă a caracteristicilor HWs pe suprafeţe extinse ale planetei. Literatura științifică indică faptul că HWs au fost unul dintre factorii responsabili pentru creșterea mortalității în multe părți ale lume. În viitor este anticipată o amplificare a caracteristicilor HWs, conducând la o creștere a impactului pe care acestea îl vor avea asupra mortalității. Cu toate acestea, prin implementarea unor măsuri riguroase de adaptare, poate fi diminuat impactul negativ care conduce la mortalitate. În concluzie, a fost remarcat faptul că s-a realizat un progres substanţial în cercetarea HWs, rămânând însă lacune importante care necesită abordare. Cuvinte-cheie: schimbări climatice, temperaturi extreme, val de căldură, factorul excesului de căldură
International Journal of Biometeorology, 2019
Climate change has profound environmental and socio-economic implications. To analyze climate cha... more Climate change has profound environmental and socio-economic implications. To analyze climate change in relation to crops, a wide variety of agro-climatic indices has been proposed by the scientific community. In this study, changes in a set of 12 agro-climatic indices related to temperature were investigated in Central Chile over a 56-year period (1961–2016). The indices were computed based on data referring to daily maximum and minimum temperatures (TX and TN). They were organized in two categories: (1) cold- and (2) heat-related indices. Cold-related indices consisted of first frost day (FFD), last frost day (LFD), frost period (FP), number of frost days (FD), accumulated frost (AF), and number of days when TN is below − 2 °C (FD-2). Heat related indices included the growing degree day (GDD) index, calculated based on four thresholds which measure the available heat resources for a wide variety of plants with different thermal requirements, and two heat stress indices which quantify the number of days with TX above 25 °C (plant heat stress (PHS)) and above 30 °C (plant high heat stress (PHHS)). Changes in agroclimatic indices were investigated using the Mann–Kendall test and the Sen’s slope estimator. The main results revealed that the FFD occurred later, while LFD occurred earlier, thus determining a shortening of the FP in the northern half of the studied area. Trends in FD, AF, and FD-2 indices generally indicated warmer conditions in terms of TN during the cold period of the year. Agro-climatic indices related to heat showed important changes in Central Chile. Thus, statistically, the majority of trends become significant and indicated enhanced condition for crops in respect of GDD indices. However, from the heat stress perspective, the analyzed indices showed that conditions become worse in most of the studied locations for crops sensible to temperatures higher than 25 and 30 °C.
Changes in precipitation (P), evapotranspiration (ET) and, implicitly, in the climatic water bala... more Changes in precipitation (P), evapotranspiration (ET) and, implicitly, in the climatic water balance (CWB), are imminent effects of climate warming. However, changes in the CWB, as a response to changes in P and ET, have not yet been analysed thoroughly enough in many parts of the world, including Romania. The present study explores the spatio-temporal changes of the CWB (difference between P and reference evapotranspiration, ET o) in Romania, based on a wide range of climatic data (P, as well as temperature, relative air humidity, sunshine duration and wind speed, necessary for computing ET o with the FAO-56 Penman-Monteith method) recorded at 70 weather stations across the country in the 1961–2013 period. As a secondary objective, the study attempts to identify the possible connections between the index's trends and large-scale atmospheric circulation, assessed based on the dynamics of certain European-scale relevant teleconnection indices. Thus, the Mann–Kendall test and Sen's slope methods were used to analyse CWB trends (but also P and ET o trends, in order to explain CWB pattern changes) annually, seasonally and in the maize and wheat growing seasons. Also, the Spearman correlation procedure and a composite analysis between interannual series of teleconnection indices and CWB were used to assess the influence of atmospheric circulation on the index's variability for all analysed time scales. The results generally showed CWB decreases (for the most part of up to −2 mm/yr, yet with a relatively low statistical significance) and highlighted an overall amplification of drier conditions on all time scales, except for autumn (CWB increases, generally of up to 1 mm/yr, but with low statistical significance). Moreover, net changes of even under −200 mm/53 yrs annually and −175 mm/53 yrs in summer and for the maize and wheat growing seasons were found in the CWB. Spatially, it was found that the country's southwestern and southeastern regions are the main epicentres of drier trends, while the northwest appears to have become wetter. Overall, the negative CWB trends are due to partial P decreases (statistically insignificant) and general ET o increases (highly statistically significant, even 100% in summer). It seems that the amplification of the climatic water deficit across the country is especially linked to the positive phases of the Arctic Oscillation and North Atlantic Oscillation, but also, in part, to those of several other teleconnection indices that affect Europe. Our results signal the necessity to adapt anthropic and ecological systems to future dryness trends countrywide, which will most likely intensify against the background of climate change expected to occur by the end of the century.
This research aims to examine changes in heat waves (HWs) over Chile from 1961 to 2016 using dail... more This research aims to examine changes in heat waves (HWs) over Chile from 1961 to 2016 using daily maximum (TX) and minimum temperature (TN) data recorded at 13 weather stations. Based on three HW-definitions and five aspects for each definition some 15 indices were calculated and analyzed for the extended summer period (November-March). The three definitions of the HWs employed in this study were based on: (1) the TX exceeding the 90th percentile for at least three consecutive days, (2) the TN exceeding the 90th percentile for at least three consecutive days, and (3) the positive values of excess heat factor (EHF) maintaining for at least three consecutive days. The five aspects calculated for each of the definitions provided information related to the frequency , duration, and intensity of HWs. Trends (be them increasing or decreasing), magnitude (change per decade) and statistical significance (p < 0.05) were identified using the ordinary least square method and the t-test. Therefore, in terms of HW aspects, the results of the HWs climate regime analysis showed that the most extreme region of Chile is the Atacama Desert, followed by the Santiago metropolitan area. Change analysis revealed that Chile experienced increasing trends in most of the HW data sets. Thus, the frequency of trend types of all HW indices time series showed an increasing trend of 79%. About 24% of the time series showed statistically significant increasing trends. Decreasing trends were found in about 20% of the analyzed data, less than 1% of which being statistically significant. Stationary trends were detected in only 2% of the series. The highest frequency of statistically significant increasing trends was found in the HWs identified based on TX, followed by those computed based on EHF. Regarding their aspects, the number of events had the highest frequency of significant increasing trends. In terms of spatial distribution, the most important changes were found in central Chile.
In this paper, we investigated changes in heat and cold waves in Romania over the period 1961–201... more In this paper, we investigated changes in heat and cold waves in Romania over the period 1961–2015 by employing a new and superior approach. It consists in using excess heat factor to identify heat waves and excess cold factor to identify cold waves. Five indices were calculated and then analysed for both heat waves and cold waves resulting in a set of ten indices. Indices for heat waves were analysed for the extended summer season (May–September), whereas those for cold waves were assessed for the extended winter (November–March). The intensity threshold was set to be equal or above the 90th percentile for heat waves, and equal or below the 10th percentile for cold waves, while the duration threshold for both heat and cold waves was of at least three consecutive days. For a better comparison with other studies conducted worldwide, and to get more information from the data sets, the percentile thresholds for heat and cold waves identification were calculated based on three reference periods: 1961–1990, 1971–2000, and 1981–2010. Trends were calculated using ordinary least square method, whereas statistical significance was assessed by the t-test. The main results indicated that changes are more substantial in the case of indices calculated based on excess heat factor compared to those based on excess cold factor, suggesting that the warming process is more reflected in heat waves rather than in cold waves. Thus, heat waves became more frequent, longer, and more intense, while cold waves became less frequent, but more intense. When the reference period for percentile threshold calculation was changed from the earliest to the most recent ones, the frequency of increasing and significant increasing trends decreased for some of the heat wave indices, while for the cold wave indices the significant downward trends increased.
In this paper, we investigated changes in heat and cold waves in Romania over the period 1961-201... more In this paper, we investigated changes in heat and cold waves in Romania over the period 1961-2015 by employing a new and superior approach. It consists in using excess heat factor to identify heat waves and excess cold factor to identify cold waves. Five indices were calculated and then analysed for both heat waves and cold waves resulting in a set of ten indices. Indices for heat waves were analysed for the extended summer season (May-September), whereas those for cold waves were assessed for the extended winter (November-March). The intensity threshold was set to be equal or above the 90th percentile for heat waves, and equal or below the 10th percentile for cold waves, while the duration threshold for both heat and cold waves was of at least three consecutive days. For a better comparison with other studies conducted worldwide, and to get more information from the data sets, the percentile thresholds for heat and cold waves identification were calculated based on three reference periods: 1961-1990, 1971-2000, and 1981-2010. Trends were calculated using ordinary least square method, whereas statistical significance was assessed by the t-test. The main results indicated that changes are more substantial in the case of indices calculated based on excess heat factor compared to those based on excess cold factor, suggesting that the warming process is more reflected in heat waves rather than in cold waves. Thus, heat waves became more frequent, longer, and more intense, while cold waves became less frequent, but more intense. When the reference period for percentile threshold calculation was changed from the earliest to the most recent ones, the frequency of increasing and significant increasing trends decreased for some of the heat wave indices, while for the cold wave indices the significant downward trends increased.
Theoretical and Applied Climatology, 2015
The main objectives of this study are to investigate the spatial distribution and changes in refe... more The main objectives of this study are to investigate the spatial distribution and changes in reference evapotranspiration (ET 0 ) in the Republic of Moldova. Monthly data of maximum and minimum air temperature, sunshine duration, relative humidity, and wind speed recorded at 14 weather stations over a period of 52 years (1961-2012) were used. ET 0 was computed based on the FAO Penman-Monteith formula. Annual and growing seasons of winter wheat and maize time series were analyzed for the 1981-2012 period as well as for the [1961][1962][1963][1964][1965][1966][1967][1968][1969][1970][1971][1972][1973][1974][1975][1976][1977][1978][1979][1980]. The trends and their statistical significance in ET 0 series were detected using Mann-Kendall test and T test, while the magnitude of the trends was estimated using Sen's slope and linear regression. For the 1981-2012 period, the results indicated that annual ET 0 had a positive trend in more than 90 % of the time series according to both parametric and nonparametric methods. The magnitude of positive trends in annual ET 0 series ranged between 13.80 and 72.07 mm/decade. In the growing seasons of winter wheat and maize, the results are similar to those found in the annual series. Significant decreasing trends dominated over the 1961-1980 period.
Global and Planetary Change, 2016
In the last two decades many climate change studies have focused on extreme temperatures as they ... more In the last two decades many climate change studies have focused on extreme temperatures as they have a significant impact on environment and society. Among the weather events generated by extreme temperatures, heat waves are some of the most harmful. The main objective of this study was to detect and analyze changes in heat waves in Romania based on daily observation data (maximum and minimum temperature) over the extended summer period (May–Sept) using a set of 10 indices and to explore the spatial patterns of changes. Heat wave data series were derived from daily maximum and minimum temperature data sets recorded in 29 weather stations across Romania over a 55-year period (1961–2015). In this study, the threshold chosen was the 90th per-centile calculated based on a 15-day window centered on each calendar day, and for three baseline periods (1961–1990, 1971–2000, and 1981–2010). Two heat wave definitions were considered: at least three consecutive days when maximum temperature exceeds 90th percentile, and at least three consecutive days when minimum temperature exceeds 90th percentile. For each of them, five variables were calculated: amplitude, magnitude, number of events, duration, and frequency. Finally, 10 indices resulted for further analysis. The main results are: most of the indices have statistically significant increasing trends; only one index for one weather station indicated statistically significant decreasing trend; the changes are more intense in case of heat waves detected based on maximum temperature compared to those obtained for heat waves identified based on minimum temperature; western and central regions of Romania are the most exposed to increasing heat waves.
Global and Planetary Change, 2013
In the last few decades, climate changes have become the most important topic in the field of cli... more In the last few decades, climate changes have become the most important topic in the field of climatology. Reference evapotranspiration (ET 0 ) is often used to identify regions prone to drought or aridity. In this paper, we used monthly data recorded in 57 weather stations in Romania over the period 1961-2007. The FAO Penman-Monteith method, based on air temperature, sunshine duration, relative humidity and wind speed, was employed in order to calculate ET 0 . Seasonal, annual, winter wheat and maize growing seasons data sets of ET 0 were generated. The trends were detected using the Mann-Kendall test and Sen's slope, while an ArcGIS software was employed for mapping the results. The main findings of the study are: positive slopes were found in 71% of the data series considered and almost 30% of the total number of series were found significant at α = 0.05; the highest frequency of the increasing trends as well as their absolute maximum magnitude were detected during summer and maize growing season; in winter, significant increasing changes are specific mainly to the extra-Carpathians regions; in autumn decreasing ET 0 is specific to more than 80% of the locations, but the significant decrease characterizes mainly the southern half of the country; during the growing seasons of maize and winter wheat, the increase of the ET 0 is dominant for the entire country. The relative change decreases with the increase of the length of the period considered: the most intense changes were detected for climatic seasons, followed by crop growing seasons and annual values. Among the climatic seasons, the highest relative increase is specific to winter followed by summer, spring and autumn, while for the crop growing seasons the values detected are similar.
International Journal of Climatology, 2013
Changes in daily extreme temperatures have been identified in many studies conducted at local, re... more Changes in daily extreme temperatures have been identified in many studies conducted at local, regional or global scales. For Romanian territory, only little research on this issue was done. In this article, the extra-Carpathians regions of Romania located southward and eastward from the Carpathians Chain were considered. This study is focused on analyzing daily extreme temperature trends at a regional scale (eastern, southern and southeastern regions of Romania) across 50 years . Data sets of daily minimum and maximum temperature recorded in 14 weather stations were analyzed. The main goal was to find changes in extreme daily temperatures using a set of 20 indices adopted from the core indices developed by ETCCDMI with appropriate modifications to suit to the analyzed territory. The main results suggest that regional temperature trends at the scale of extra-Carpathians areas of Romania are similar to those calculated for global and European continental scales; the climate has become warmer during the last decades. It has been identified that both extreme daily maximum and minimum temperatures have increased in the analyzed areas. For all the indices related to hot temperature most trends are significantly positive. The strongest increase was detected for hot related extremes such as summer days and tropical nights as well as for maximum values of maximum and minimum daily temperatures. For indices related to cold there are different sign slopes, but negative slopes prevail, especially for number of days under a defined threshold. This is also an evidence of the important warming in the area. Generally, it was found that the daily maximum temperature is getting more extreme, whereas the minimum is getting less extreme. Copyright 2012 Royal Meteorological Society KEY WORDS daily extreme temperature indices; daily maximum and minimum temperatures; trend; Mann-Kendall test and Sen's slope; extra-Carpathians areas of Romania
14th SGEM GeoConference on ENERGY AND CLEAN TECHNOLOGIES, 2014
Changes in daily extremes events is one of the most important topic in climate literature and man... more Changes in daily extremes events is one of the most important topic in climate literature and many studies have been conducted so far at local or regional scale worldwide. For the Romanian territory, only little research on this issue was done. In this article, the Carpathian and intra-Carpathians regions of Romania were considered. This study is focused on analyzing the trends of daily extreme temperature indices at a regional scale over a period of 50 years: 1961-2010. Data sets of daily minimum and maximum temperature recorded in 10 weather stations were analyzed. The main goal was to find changes in daily extreme temperatures by using a set of 9 indices adopted from the core indices developed by ETCCDMI with appropriate modifications to suit to the analyzed territory. The main results suggest that the climate has become warmer during the last decades. Trends of extreme temperature indices at the regional scale of Carpathians and intra-Carpathians areas are increasing for most of the indices calculated. It has been identified that both extreme daily maximum and minimum temperatures indices have increased in the analyzed areas. For all the indices related to hot temperature most trends are statistically significant.
Quaternary International, 2015
ABSTRACT Changes in daily extreme precipitation have been identified in many studies conducted at... more ABSTRACT Changes in daily extreme precipitation have been identified in many studies conducted at local, regional, or global scales. In Romania, little research on this issue has been done. The present study focuses on the analysis of the trends in daily extreme precipitation indices over a period of 53 years (1961–2013). Data sets of daily precipitation recorded in 34 weather stations were analyzed. Among them, three are located in the Carpathians and four on the Black Sea Coast. The main goal was to find out changes in extreme daily precipitation using a set of 13 indices adopted from the core indices developed by ETCCDMI adapted to suit to the studied area. The series of indices and their trends were generated using RClimDex software. The trends have been calculated by employing modified Mann–Kendall test and Sen's slope. Generally, the climate of Romania has become wetter over the 53-yr period considered, especially in the northern regions, although the spatial distribution of the significant trend slopes in the area is extremely irregular. Based on fixed threshold indices analysis, extreme precipitation events are characterized by a decreasing in the total number of precipitation days (R0.1), and a dominant increasing trend for the number of isolated days with moderate and heavy precipitation (R5, R10).
Changes in daily extremes events is one of the most important topic in climate literature and man... more Changes in daily extremes events is one of the most important topic in climate literature and many studies have been conducted so far at local or regional scale worldwide. For the Romanian territory, only little research on this issue was done. In this article, the Carpathian and intra-Carpathians regions of Romania were considered. This study is focused on analyzing the trends of daily extreme temperature indices at a regional scale over a period of 50 years: 1961–2010. Data sets of daily minimum and maximum temperature recorded in 10 weather stations were analyzed. The main goal was to find changes in daily extreme temperatures by using a set of 9 indices adopted from the core indices developed by ETCCDMI with appropriate modifications to suit to the analyzed territory. The main results suggest that the climate has become warmer during the last decades. Trends of extreme temperature indices at the regional scale of Carpathians and intra-Carpathians areas are increasing for most of the indices calculated. It has been identified that both extreme daily maximum and minimum temperatures indices have increased in the analyzed areas. For all the indices related to hot temperature most trends are statistically significant.
Changes in daily extreme precipitation have been identified in many studies conducted at local, r... more Changes in daily extreme precipitation have been identified in many studies conducted at local, regional,
or global scales. In Romania, little research on this issue has been done. The present study focuses on the
analysis of the trends in daily extreme precipitation indices over a period of 53 years (1961e2013). Data
sets of daily precipitation recorded in 34 weather stations were analyzed. Among them, three are located
in the Carpathians and four on the Black Sea Coast. The main goal was to find out changes in extreme
daily precipitation using a set of 13 indices adopted from the core indices developed by ETCCDMI
adapted to suit to the studied area. The series of indices and their trends were generated using RClimDex
software. The trends have been calculated by employing modified ManneKendall test and Sen's slope.
Generally, the climate of Romania has become wetter over the 53-yr period considered, especially in the
northern regions, although the spatial distribution of the significant trend slopes in the area is extremely
irregular. Based on fixed threshold indices analysis, extreme precipitation events are characterized by a
decreasing in the total number of precipitation days (R0.1), and a dominant increasing trend for the
number of isolated days with moderate and heavy precipitation (R5, R10).
The main objectives of this study are to investigate the spatial distribution and changes in refe... more The main objectives of this study are to investigate the spatial distribution and changes in reference evapotranspiration (ET0) in the Republic of Moldova. Monthly data of maximum and minimum air temperature, sunshine duration, relative humidity, and wind speed recorded at 14 weather stations over a period of 52 years (1961–2012) were used. ET0 was computed based on the FAO Penman-Monteith formula. Annual and growing seasons of winter wheat and maize time series were analyzed for the 1981–2012 period as well as for the 1961–1980. The trends and their statistical significance in ET0 series were detected using Mann-Kendall test and T test, while the magnitude of the trends was estimated using Sen’s slope and linear regression. For the 1981–2012 period, the results indicated that annual ET0 had a positive trend in more than 90 % of the time series according to both parametric and nonparametric methods. The magnitude of positive trends in annual ET0 series ranged between 13.80 and 72.07 mm/decade. In the growing seasons of winter wheat and maize, the results are similar to those found in the annual series. Significant decreasing trends dominated over the 1961–1980 period.
Global and Planetary Change, 2013
In the last few decades, climate changes have become the most important topic in the field of cli... more In the last few decades, climate changes have become the most important topic in the field of climatology. Reference evapotranspiration (ET0) is often used to identify regions prone to drought or aridity. In this paper, we used monthly data recorded in 57weather stations in Romania over the period 1961–2007. The FAO Penman–Monteith method, based on air temperature, sunshine duration, relative humidity andwind speed,was employed in order to calculate ET0. Seasonal, annual, winter wheat and maize growing seasons data sets of ET0 were generated. The trends were detected using the Mann–Kendall test and Sen's slope, while an ArcGIS software was employed for mapping the results. The main findings of the study are: positive slopes were found in 71% of the data series considered and almost 30% of the total number of series were found significant at α = 0.05; the highest frequency of the increasing trends as well as their absolute maximum magnitude were detected during summer and maize growing season; in winter, significant increasing changes are specific mainly to the extra-Carpathians regions; in autumn decreasing ET0 is specific to more than 80% of the locations, but the significant decrease characterizes mainly the southern half of the country; during the growing seasons of maize and winter wheat, the increase of the ET0 is dominant for the entire country. The relative change decreases with the increase of the length of the period considered: the most intense changes were detected for climatic seasons, followed by crop growing seasons and annual values. Among the climatic seasons, the highest relative increase is specific to winter followed by summer, spring and autumn, while for the crop growing seasons the values detected are similar.