Volume X |

The Geological and Morphological Structural Control in the Cricovul Dulce River Basin

Abstract: This paper aims to analyze the correlations between the tectonic, structural and lithological elements in the Cricovul Dulce river Basin and their reflection in the landscape morphology. The Cricovul Dulce river basin’s position in the Curvature Subcarpathians and Cricovul piedmont plain led to different structural and lithological characteristics which favored a certain type of geomorphological landscape evolution in accordance with the physical-geographical particularities. The faults (Câmpina, Colibaşi), the Vârfuri- Vişinesti- Draganeasa dislocation line, and the presence of anticlines (Siliştea Dealului, Gura Ocniţei- Moreni, Babanucului) and of synclines (Malurile- Valea Lungă, Ruda) in the Cricovul Dulce Basin, influence the dynamics in the morphographical development of the entire region. The lithology, the clastic rocks (sands, marls, clays, gravels), unconsolidated sometimes, and the layers with different hardness, increase the morphodinamic processes and give rise to a structural relief specific to the Subcarpathians regions. The valleys adapt to the structure and thus, there are different types of steams: subsequent, obsequent and consequent. The geology gets even more complicated due to the presence of some coal layers (the perimeter of Filipesti de Padure) and salt massifs (Moreni, Colibasi) in the basin. The relief of the Cricovul Dulce Basin reflects the lithological composition and structure of the region over which overlaps, resulting from this point of view a diversity of landscapes

Volume X |

The Impact of Solar Activity on the Greatest Forest Fires of Deliblatska peščara (Serbia)

Abstract: The subject of research refers to potential causative-effective connection between processes on the sun and the largest forest fires in Deliblatska peščara. The four greatest forest fires in Deliblatska peščara in the period 1948-2009 were in 1973, 1990, 1996 and 2007. The analysis of solar activity, especially the solar wind data and the analysis of the fire events were used in the research of the possibility of mutual connection. There are no enough data for the fire that occurred in 1973 on the basis of which the connection with processes on the sun would be determined. The fire from 1990 developed in the conditions of intensive solar activity and it was probably caused by the solar wind. There are some indications that the solar wind from energetic region 7981 caused the largest forest fire in Deliblatska peščara in 1996. For fire that occurred in 2007, the energy source (coronary hole CH279) was determined, as well as the moving of the solar wind particles. During the investigated fires the phenomena characterising fires caused by solar wind were recorded, such as frequent wind direction changes and appearance of fire on different locations at the same time. The statistical analysis of the number of fires in Deliblatska peščara and AMO also indicated the anti-phase connection between these events. Even though the obtained results have shown the signal of the connection between charged particles and initial phase of fire, the laboratory testing is necessary to prove the mentioned hypothesis.

Volume X |

Observed changes in precipitation in the Danube river lower basin in the context of climate change

Abstract: The study presents the observed variability and changes in precipitation regime in the Danube river lower basin, which is situated along both sides of the border between Bulgaria and Romania. The research is based on monthly precipitation totals recorded at 22 meteorological stations from Bulgaria and Romania. The investigated period is 1961-2007 out of which two reference periods are considered, the last 30 years (1978-2007) and the usually used WMO reference for the contemporary climate (1961-1990). The main objective of the study is to give actual information about precipitation variability in the region in the context of global climate change. The results of the work point out on some characteristics of extreme precipitation events in the region – drought and high precipitation, and on the role of natural mechanisms for precipitation variability. Based on the statistical methods we have used, the results can be summarized as follows: – Summer precipitation represents 30-35% of annual precipitation total followed by spring precipitation with about 25-28% of annual values. Autumn precipitation is between 22-24% of annual values in most of the stations. Winter precipitation represents about 20% of annual precipitation; – The wet periods have been observed at the end of the 1960’s and at the beginning of the 1970’s; – The intensive drought from 1983 to 1993 has been confirmed by calculating the precipitation indices like as Rainfall Anomaly Index and Cumulative Anomaly Index. The driest year during the investigated period was 2000; – Increasing occurrence of extremely wet months has been observed since 2002.

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 X |

The Climatic Water Deficit in South Oltenia Using the Thornthwaite Method

Abstract: Understanding the dryness and drought phenomena is fundamental in explaining the landscape features and the rational use of water resources in a region. The authors aim to assess the climatic water deficit (WD) in one of the most sensitive regions in Romania in terms of aridity: Southern Oltenia. Defining and characterizing the intense aridity was done based on the Thornthwaite method under a multi-annual regime (1961-2007) and during the growing season (April-October) in order to reveal the climate suitability for human activity and the optimum conditions for the main crops. In southern Oltenia the Thornthwaite aridity index values (Iar-TH) (%) defines an arid area, increasing from north to south and south-west from 40-45% to 50%. The highest values displaying a pronounced aridity (Iar-TH ≥ 50%) cover a significant part of the Blahniţa Plain, Desnăţui Plain, Southern Romanaţi Plain (Dăbuleni Field), the Jiu Valley and the entire Danube Plain (about 65% of the entire surface).