fg

Subscribe2


 

Volume XIV |

Near surface thermal characteristics of alpine steep rockwalls in the Retezat Mountains

Abstract: The characteristics of the near surface thermal regime of two rockwalls with different aspect in the Retezat Mountains were investigated using two miniature thermistors. Three one-year (2012-2013; 2013-2014 and 2014-2015) rock surface temperature time series were available for the north facing rockwall, whereas only two seasons were analyzed for the south facing rockwall. The mean annual rock surface temperature (MARST) values were with 1.5-2°C colder on the northern rockwall compared with the southern steep bedrock face. Due to long daily exposure to sunshine, the south facing rockwall experienced more diurnal freeze-thaw cycles during the cold season compared to the north facing rockwall. Overall, the thermistor with a southern aspect recorded 40 and 55 more freeze-thaw cycles than the northern one. A greater number of effective freeze-thaw cycles were measured on the south facing rockwall. The maximum daily amplitude on the southern rockwall is three times higher than on the north-facing location (39.1°C compared to 13.6°C). Based on our findings it seems that the MARST values recorded on the shaded face of the steep bedrock suggest a quite likely absence of permafrost, whereas the MARST values at TPR indicate a quite certain absence of permafrost.

Volume X |

Application of Object Based Image Analysis for Glacial Cirques Detection. Case Study: The Ţarcu Mountains (Southern Carpathians)

Abstract: Geomorphologic mapping is an important fact in many research studies and the traditional methods are time consuming and expensive. This paper aims to develop a semi-automated rule-based method for the detection of glacial cirques for a test area located in the Ţarcu Mountains (Southern Carpathians) in an object-oriented approach. In this study we have established the morphometric characteristics of the glacial cirques developed in a particularly geomorphologic context at the edge of planation surfaces, using a 10 m horizontal resolution DEM (Digital Elevation Model). The parameters extracted from DEM (i.e. curvature) were further used in segmentation and classification process. Also, other factors were introduced in the rule set, as the context regarding neighboring objects like planation surfaces to the target class. The most important factor in segmentation was the curvature and to choose an appropriate scale factor we have used the available ESP (Estimation of Scale Parameter) tool. The results achieved were very close to the field reality, except for some areas where there are large negative landforms such as gullies and torrents, which were identified as objects belonging to glacial cirques class and also some roches moutonnées with high positive curvature values, objects that could be filtered manually by the user based on previous field knowledge and ancillary data such as orthophotoplans and the geomorphologic map of glacial relief in the Ţarcu Mountains. For further research, we intend to identify the characteristic thresholds for morphometric parameters that can be integrated in a set of rules in order to detect and classify other type of landforms in the alpine domain of the Ţarcu Mountains.

Volume X |

Features of the Ski Area from the Romanian Banat

Abstract: The Romanian Banat is endowed with an important mountain area composed of the Banatului Mountains and the north-western part of the Retezeat-Godeanu Range, i.e. Ţarcu – Muntele Mic. The purpose of our paper is to make an account of the features of the two important ski areas within this mountain area: Ţarcu – Muntele Mic and Semenic. Their structure evolved over time according to the local and regional interest, but also due to more recent activities of the Romanian investors. Our research concluded that both ski domains have a great natural potential to sustain winter-sports and to further develop what today are two very small resorts. They have a low capability of attraction due to the small capacity of the pistes and to the fact that each resort has only two ski-lifts. In both cases the access is rather limited and as far as accommodation is concerned in both cases it is disproportional in relation with the provisioned capacity of the ski pistes. Having these aspects in view, we conclude that these resorts do not represent as yet a major attraction, especially due to the fact that there are undercapitalized and underdeveloped for the raising demand of the regional market for winter-sports. On the other hand in both cases projects have already been blue-printed by the aforementioned investors which are waiting to be undertaken for development.

Volume VIII |

The Semiautomated Identification of the Planation Surfaces on the Basis of the Digital Terrain Model. Case Study: The Mehedinti Mountains (Southern Carpathians)

Abstract: The paper presents a method for the semiautomated classification of the planation surfaces, using the Digital Terrain Model (DTM) and the object-oriented analysis. The effort undergone for developing such a method has a number of motivations. The first one is that these landforms are very important for decoding the geomorphologic evolution of the relief units. The second motivation concerns the fact that their identification and mapping, by using classical means, represents a difficult demarche, which requires a lot of time. Finally, the already-known limits of the relief analysis using the DTM at pixel level impose the testing of an object-oriented analysis, in which the area under study is divided into objects of various dimensions, as homogenous as possible from the viewpoint of one or more properties. The method that we propose supposes the following steps: the realisation of the slope model and of the flow model, starting from the DTM; the division, by segmentation into objects that are as homogenous as possible from the viewpoint of the slope; the classification of the objects into landforms (planation surfaces) by using the fuzzy functions and taking into account more factors simultaneously (the average slope value, the minimum slope value, the flow coefficient and the altitude), and the selection and grouping of the identified surfaces into sculptural complexes. The first stages represent the automated part of the method, while the last one requires a detailed geomorphologic analysis of the area, as well as the validation of the results on the field. The method was firstly developed for the Godeanu Mountains, the map of the levelled surfaces (Niculescu, 1965) being used for the identification of the parameters included in the algorithm, as well as for testing the results obtained in the view of the improvement of the method. Due to the good results thus obtained, the same method was also used for mapping the levelled surfaces in the Mehedinţi Mountains, and, along with the field observations, there was realised the planation surfaces map for this relief unit.