Volume XVI |

Considerations upon extreme temperatures on Romanian territory

Abstract: In this article we analyse the evolution in time of extreme temperatures significant for Romania with a focus on absolute extreme temperatures recorded on the overall present territory. After thoroughly investigating the credible sources referenced at the end of the paper, we present in chronological order the records for absolute minimum temperatures, and absolute maximum temperatures which were measured at the meteorological stations on the present territory of Romania, according to the availability of the data, i.e. the last two decades of the 19th century up until 2017.  We classify and discuss the sources of climatological data in the form of minimum and maximum temperatures. The measurements of meteorological parameters on the current national territory were recorded since 1770 at Iași (cf. Dissescu 1931 and also http://www.meteoromania.ro/anm2/despre-noi/istoric/ – page in Romanian as of 30.03.2017). For a systematic approach with credible data, at least another century passed, until Ștefan Hepites (1851-1922) founded in 1884 in Bucharest the Central Meteorological Institute of Romania (I.M.C. in Romanian) (Dissescu, 1931 and cf. the ANM web page quoted earlier). The newly created Institute did not include the meteorological stations which were present at that time in Transylvania, but only the ones on the official Romanian territory of 1859-1918 made up of Moldavia and Wallachia. This paper argues in favour of the process of global warming (GW) and its effects upon the evolution of extreme temperature values in a certain time interval. The conclusions stemming from the investigation of the dataset in this paper should provide a helpful and necessary point of departure in subsequent research of climatologists in their quest of identifying the correct model of future climate. Our article should be regarded as part of a series of analyses of the variability of the climate in Romania, the recent influence of global warming on it and on certain climatological parameters in particular.

Volume XIII |

Considerations on Desertification Phenomenon in Oltenia

Abstract: The paper analyses the desertification phenomena in Oltenia, which have been more intense after 1990. Significant references are also made to the overall aspect for the entire country. The droughty periods have different meteorological characteristics compared to the last century such as: their association with intense heat waves, intensity and important areas of extension. These were caused by stable and persistent anticyclonic regimes which affected most part of the European continent. The paper is a part of series of extended studies on climate variability in Oltenia (Bogdan and Niculescu, 1999, Bogdan and Marinică, 2007, Marinică and Marinică, 2010; Marinică, 2006, 2009). The paper is useful to students, master graduates and to all specialists in climatology.

Volume XI |

Agroclimatic conditions in Oltenia during the spring of 2011

Abstract: The paper analyses the climatic and agroclimatic conditions during the spring of 2011. Although the climatic global warming process continues, in some years, the climatic evolutions are atypical in Oltenia as well as in the entire country, and, consequently, the spring of 2011 was cold and droughty. Compared to the last 12 springs, the thermal regime indicates that the spring of 2011 was unique, and the pluviometric regime that it was droughty, although the agricultural crops were not affected due to the lower thermal regime that maintained a satisfactory degree of the soil humidity. The late spring hoarfrosts on 7 and 8 May have also had damaging effects in Oltenia. In consequence, there were some stagnation periods for the agricultural crops, and some important delays for the vegetables crops, and there were significant damages in the places where the seedlings were removed in the field. As a consequence of the thermal variations, there have been some diseases and pests, especially Monilinia laxa in stone fruits. Although the periods of weather cooling are considered beneficial to the climate general evolution on the planet, if they appear in the late spring, they represent an important climatic risk factor. Thus, their forecast is welcome especially for the agriculture. This paper is useful for the Ph.D. and master graduates and to all the researchers in the climate and agroclimate field.

Volume X |

Indexes of Spring Arrival between 2000 and 2010 in Oltenia

Abstract: The present paper deals with the conditions related to spring arrival in Oltenia between 2000 and 2010. A first general evaluation may be achieved by comparing the mean general indexes for the entire region of Oltenia for each spring, which are calculated as a mean of the indexes of spring arrival for all the meteorological stations from Oltenia, including the mountainous area.
Out of the 11 analysed years, the lowest value was 171.1°C, registered in the spring of 2003, which followed the coldest winter (2002-2003) of the studied interval (Bogdan, Marinică, Marinică, 2010); the highest value reached 460.7°C and it was registered in the spring of 2002 that followed a warm winter, 2001-2002, the general mean of which is on the 9th place in the increasing hierarchy of the general temperature means for winter during the analysed interval. The general mean of the index for the 11 analysed years is 366.0°C with a positive percentage deviation of 43.2%, which, according to a Hellmann’s type of criterion established by us, emphasizes that springs were early (E) during the entire period. The negative deviation of the latest spring (2003) was of -29.1.1%, which means a late spring (L). The second value of the index was 262.9°C, which means a normal spring. The positive deviation of this general mean of the spring arrival index for the spring in question (2003) reached 7.1%, which means a normal spring, in fact, the single normal spring of the entire interval. For Oltenia, as well as for the entire country, the decade 2000-2010 was warm. It stands out through – the warmest winters, which also registered the highest frequency, the earliest springs, the hottest summers with the more extended dog days’ periods, the exceeding of certain absolute thermal maximum values in the country, some of them considered real “climatic thresholds”, all induced by the climate variation limits of the end of the 20th century and the beginning of the 21st century. The predominance of early springs represent a proof of the regional climatic changes during this interval.

Volume IX |

Comparison between the Oltenia Plain and the Southern Dobroudja Plateau in Terms of Pluviometric Deficit

Abstract: The Oltenia Plain and the Southern Dobroudja Plateau are two regions located in the two southern extremities, namely the south-western and the south-eastern extremities of Romania, which display distinct climatic features imposed by multiple climatic influences. The climatic evolution, especially in the last three decades, and the regional manifestations of the climatic phenomena related to global warming induced significant changes within the mentioned regions. In this context, we mention the pluviometric deficit. In the present paper, we have analysed the pluviometric deficit (annual and the warm semester of the year) within the Oltenia Plain and the Southern Dobroudja Plateau registered in the last half of the century (starting with 1961). We made a comparative analysis. The significant differences clearly emphasize the aridization tendency of the regional climate. The paper is useful for climatologists, as well as for students, master and PhD students.