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 XIII |

Analysis of precipitation characteristics and trends for the Getic Piedmont and Subcarpathians, Oltenia region, Romania

Abstract: Changes in precipitation characteristics of the hilly area of Oltenia, covering the western parts of the Getic Piedmont and SubCarpathians, were analysed, based on monthly rainfall data, for the timeframe 1961 to 2010. The precipitation trend analysis for the period 1961-2010 shows different results–increasing precipitation in winter half part of the year for most of the Subcarpathian area and a rainfall decrease in summer half of the year for the entire region. The piedmont part of the study area, with dominant agricultural land use, shows the highest spring precipitation decrease, whereas in the Subcarpathian area, summer and autumn precipitation increase is more pronounced. The positive trends are spatially the most homogenous in August, September and October, while the most uniform negative trends were recorded in February, May and November. At annual level, the most significant decrease corresponds to the piedmont, while the rest of the region displays an insignificant positive trend. The SPA emphasized that normal years (deviations oscillating between -1.00 and +1.00) predominate; however, in the eastern part of the region there are lower percentages compared to the western part (70-74% compared to 64-66%). At the same time, in the east, the share of dry weather is double compared to the western part, where rainy weather predominates.

Volume XIII |

Assessment of the long-term wind energy resources in the Southern Bârlad Plateau. An applied climatology study

Abstract: In order to evaluate the long-term wind conditions and energy resources in the Southern Bârlad Plateau, the WINDATLAS method has been applied, using the numerical software programs WindPRO 2.7 and WAsP 9. For this purpose, 2 years (2008 – 2010) of in-situ wind measurement data from two locations were used. These time series have been adjusted to a 30-year long-term period (1981-2010), using NCAR global weather analyses data, and validated with the monthly means of the wind speed recorded at Galați meteorological station (1981-2010). On the basis of the new generated long-term time series, local wind statistics have been obtained, which were used for wind conditions assessment and energy yield calculations within the study area. The average wind speed, the Weibull parameters for the vertical wind profile, as well as the expected wind energy resources have been determined. The Southern Bârlad Plateau is characterized by high wind energy potential demonstrated by long-term averaged wind speeds larger than 7 m/s (at 120 m a.g.l.), similar to Dobrogea region, and by corresponding wind energy values of more than 3000 kWh/m2 at hill top positions. Another key issue is that the energy potential of this area is relatively constant at multi-annual scale, with prevailing winds from northern and southern directions, making it highly suitable for the development of Multi-Megawatt wind farms. The results obtained by applying this complex methodology can be practically valorized by being further integrated in energy production estimates and feasibility studies for wind farms.

Volume XIII |

Seasonal river flow variability of the Middle and Lower Danube and its tributaries

Abstract: The seasonality of stream flow variability indicates special feature of local cycle of precipitations, evaporation and the timing of snow melt. This study presents seasonal occurrence of maximal and minimal annual flows and spatial variability of seasonal index (Is) in the Middle and Lower Danube basin. The analysis is based on 47 time series of monthly runoff (12 for the Danube and 35 for its tributaries), which are collected from public database. The results show that the maximum annual stream flow appears during all months, but with highest frequency in April for 68% from watersheds. It varies between one and 60% (Danube – Baziaz). The monthly flow is concentrated in summer–autumn hydrological season, except for the Jalomita, Siret and Prut river basins, where it is in the winter. The highest frequency of minimum monthly runoff for the Danube and the Tisza is in October and November and for the Sava and Velika Morava – in August and September. The lowest and highest monthly discharge of the given month in the entire period were recorded in different years. Seasonal index (Is) is between 0.98 and 3.18. It is about 1.00 for the Danube and more than 2.00 for the Tisza, Ialomita, Siret and Prut watersheds. Is is stability – coefficient of variation is up to 0.30 with the exception of several river basins. Stream flow variability of the Middle and Lower Danube can provide valuable information for scientific studies and integrated management of water resources.

Volume XIII |

Analysis of River regime and Water balance of the Temštica River Basin (South-East Serbia) during the 1980-2012 Period

Abstract: In this study we analyze river regime and water balance of the Temštica River on the base of thirty three year (1980 – 2012) data series. For this study period, the mean water level of the Temštica River was 41 cm. The average discharge of the Temštica River at Staničenje station for the investigated period is 5.63 m3/s. Annual changes in average discharge is similar to the annual course of mean monthly low and high discharge values. It is concluded that the Temštica river has moderate – continental river regime. Although the precipitation quantity is not so low – 596 mm per year, of which 217.05 mm or 36.42 % of it runoffs, and 378.92 mm, or 63.58% evaporates. The ratio of the components of the water balance in the basin is not convenient, appropriate measures to improve the situation in this river basin should be taken.