fg
Volume XVIII |

A review of recent studies on heat wave definitions, mechanisms, changes, and impact on mortality

Abstract: 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.

Volume XVIII |

Hydro-ecological investigation of the Lazeshchyna River in Transcarpathian region of Ukraine

Abstract: This paper focuses on the hydro-biological and hydro-chemical analysis of the Lazeshchyna River, one of the tributaries of the Tisza River from the cross-border territory within Rakhiv area of Ukraine’s Transcarpathian region. For this purpose, we used the results of route survey, hydro-biological and hydro-chemical analysis of the Lazeshchyna River surface water samples, which were collected forhydrochemical studies in 2017-2018. On the basis of water sampling we thoroughly analyzed the hydro-chemical water quality indicators of Lazeshchyna River according to the following groups of indicators: physic and chemical features, organic matter, water mineralization, major ions, nutrients, trace elements and specific pollutants. Hydrobiological studies were conducted in 2015-2016. Based on them, the water quality was assessed according to the Trent Biotic Index bioindication. The ratio of actual and maximum permissible concentration (MPC) hydro-chemical parameters are investigated, moreover we pointed out the seasonality in the ratio of water consumption and concentration of individual indicators. The study underlines the role of natural and anthropogenic factors for the Lazeshchyna River water quality.

Volume XVIII |

Human impact due to the capitalization of water resources within the Jiu Gorge National Park

Abstract: Within the Jiu Gorge National Park, there was a project, which almost draws to an end, for the hydro-energetic capitaliza-tion of the river, which implies a potentially negative impact of this investment on the aquatic sector of the Jiu river in this sector. The current study analyses the hydrological regime of the Jiu river within the gorge sector (natural flow and controlled flow for the technical-economic capitalization parameters) and the impact on natural landscapes due to building and construction sites, bringing arguments and solutions for meeting the declared objective of conserving the aquatic ecosystems within the Jiu Gorge National Park. Thus, there must be ensured a minimum discharge (ecological discharge) on all rivers within the national park and Natura 2000 sit, to provide for this mere purpose of this category of protected areas.

Volume XVIII |

How much open water do waterbirds have in the Banat Plain? The first permanent inland water bodies inventory at 10-m resolution using Sentinel-2 imagery at regional – scale

Abstract: In the Banat Plain were recorded more than half of the number of bird species in Romania. There are eleven Nature 2000 Bird Protection Sites (SPAs) and in all of them have been registered aquatic bird species. The water surface areas were greatly reduced since the starting of the hydro-technical works 300 years ago. Nowadays, the anthropic pressure associated with the more frequent drought periods continues to threaten the water bodies, on whose existence the numerous aquatic birds depend. For the mapping and evaluation of open water surfaces in the Banat Plain, in the context of a lack of precise, consistent maps and data, the first water bodies inventory at 10-m resolution was made based on Sentinel-2 multispectral satellite images. The heterogeneous and fragmented landscape, with a great diversity of aquatic units, conducted us to develop an object-oriented approach, which allowed a multi-scale classification process. Both spectral bands and normalized differentiation water indices were used in the rule-based classification algorithm for water detection. The accuracy assessment indicated a very good overall accuracy of 96%, with a Kappa coefficient of 0.91. Also in our dataset, the small water bodies were mapped more accurately than in the other six water bodies datasets at global or European scale we compared with. The results drawn from both qualitative and quantitative assessments indicated that the water dataset developed in this study could be used as an inventory and a reference map for the permanent open water areas from the Banat Plain. It may represent the starting point for better aquatic management and elaboration of ecological strategies to support bird necessities and to counteract the increasing vulnerability and environmental threatening of waterbird species.

Volume XVIII |

Aridity risk in the west of the Oltenia Plain: natural factors and human impacts on land degradation

Abstract: The lands of southern Oltenia had different evolution stages in the last century being influenced by the climatic factor but especially by the anthropic factor. From the extensive areas of ponds and marshes in the pre-war period to drainage, embankments, irrigation systems and planting of the windbreakers and shelterbelts in the 50s – 60s (reflected in the agricultural peak of the 70s – 80s) and to the present day, we are witnessing the aridization of the lands and the extension of the predominantly sandy areas, impracticable to the current type of agriculture.
After 1990, agriculture in the southern part of the Oltenia Plain had an accelerated decline caused by the destruction of the irrigation systems, the deforestation of the windbreakers and shelterbelts, the situation of land ownership and the failure of the adaptation of the crops to the soil types. In 2012 the percentages of irrigated areas reached 0% capacity used out of 76,820 ha in the Blahnița Plain and 1% capacity used out of 299,621 ha in the Oltenia Plain. All these have led to land degradation and amplification of geomorphological processes, especially on sandy surfaces, where the lack of vegetal layer together with the wind process lead to destabilization and movement of sand dunes. This article aims to conduct a spatial-temporal analysis of several types of lands exposed to drying, whose surface has increased considerably to almost 50,000 hectares. Another 50,000 hectares are predisposed to this phenomenon in the Oltenia Plain, on the western part of Jiu. An environmental management strategy for a sustainable development could be made for the protection of the lands against the winds by planting windbreakers and shelterbelts of fast growing species (acacia, hybrid poplar, wild pine, walnut tree). The research methodology involved the processing of the annual average data on temperature, precipitation and wind direction from the weather stations in south-west Oltenia, the processing of the data from the Landsat, Corine maps, as well as the analysis of the data provided by the examination reports on the occupation of land offered by the Ministry of Regional Development and Public Administration. In the analysis of land degradation as a result of the aridization process, the situation of the current vegetation layer was taken into consideration using the NDVI (Normalized Difference Vegetation Index) and data taken from Corine Land Cover between 1990 and 2006 regarding the change of the land use in the Oltenia Plain.