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Climatology

Volume XIV |

Considerations on the influence of micro urban heat islands to the temperature – humidity index in Craiova

Abstract: According to National Administration of Meteorology, July month of 2015, will represent one of the longest periods with canicular temperatures in the last decades. In Oltenia region and in Craiova city, too, yellow or orange code warning, had to be declared. To determine thermal discomfort sensation felt by the population of Craiova, experimental research concerning micrometeorological measurements of the real temperature and relative humidity that contribute to the local Temperature – Humidity Index (THI) value was performed. According to the experimental research results, con-firmed by using thermovision too, within Craiova, four micro urban heat islands were identified. Despite the low mean value of relative humidity, due to the temperature’s high mean value, in these hot spots the THI average was 94.93, and the thermal discomfort sensation would have made necessary special protection measures. The same air micrometeorological parameters in these four hot spots were compared with the ones recorded in English Park where due to vegetation and trees’ shadow, the THI average was 84.87, thus the thermal discomfort sensation would have made necessary adequate protection measures. The paper proposes several practical methods that would be utilized in order to decrease the pavements’ and buildings’ walls temperatures, or to increase the vegetation surfaces that contribute to the THI de-creasing in the micro urban heat islands of Craiova city.

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 XII |

The impact of the drought on the main crops cultivated in Northeastern Bulgaria

Abstract: Drought is one of the consequences of a reduction of rainfall over a long period of time. Often a number of meteorological elements as high temperatures, strong winds and low relative humidity occurs in conjunction with the drought. These facts make drought very strongly expressed. The present paper aims to analyze the intensity and the seasonal differences of meteorological drought in Northeastern Bulgaria and to characterize the drought impact on the main crops cultivated in the study area. The tendencies of the seasonal and the annual air temperatures and precipitation are investigated. Drought periods are revealed on the base of precipitation anomalies and the drought indices as Standartized Precipitation Index (SPI) and De Martonne Index. The driest years for the period 1961 – 2011 have been established. The production of the main crops in the study area is analyzed on the background of climate change. The information from climate models is used in order to describe future climate and to make the recommendations for crop cultivation in relation to climate impact.