TY - JOUR A1 - Sponholz, Barbara A1 - Baumhauer, Roland A1 - Felix-Hennignsen, P. T1 - Fulgurites in the southern central Sahara, Republic of Niger and their palaeoenvironmental significance N2 - The mineralogical and chemical characteristics of fulgurites ( = natural glasses forrned by lightning strikes to the ground) from the southern Centrat Sahara (Niger) are presented. The fulgurites are indicators of thunderstorms. The northernmost important fulgurite formation in the study area reached up to about l8°N, with decreasing fulgurite concentration from south to north. Their distribution pattern and the relative dating of their formation in relation to Iandscape history from the Late Pleistocene onwards (e.g., palaeolakes, palaeosols), and to Neolithic settlement reveals their value as palaeoenvironmental indicators. They indicate: (1) local palaeoenvironmental conditions depending on the topographical situation in a complex dune relief; (2) climatic change during the mid-Holocene from northerly rains to southerly rains; and (3) the northernmost Iimit of important thunderstorrns and rainfall activity since this time in the southern Centrat Sahara. KW - Sahara KW - Niger KW - Fulgurite KW - fulgurites KW - lightning KW - thunderstorms KW - Sahara KW - Holocene KW - climatic change KW - palaeosols KW - Neolithic Y1 - 1993 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-63337 ER - TY - JOUR A1 - Schäfer, Christian A1 - Fäth, Julian A1 - Kneisel, Christof A1 - Baumhauer, Roland A1 - Ullmann, Tobias T1 - Multidimensional hydrological modeling of a forested catchment in a German low mountain range using a modular runoff and water balance model JF - Frontiers in Forests and Global Change N2 - Sufficient plant-available water is one of the most important requirements for vital, stable, and well-growing forest stands. In the face of climate change, there are various approaches to derive recommendations considering tree species selection based on plant-available water provided by measurements or simulations. Owing to the small-parcel management of Central European forests as well as small-spatial variation of soil and stand properties, in situ data collection for individual forest stands of large areas is not feasible, considering time and cost effort. This problem can be addressed using physically based modeling, aiming to numerically simulate the water balance. In this study, we parameterized, calibrated, and verified the hydrological multidimensional WaSiM-ETH model to assess the water balance at a spatial resolution of 30 m in a German forested catchment area (136.4 km2) for the period 2000–2021 using selected in situ data, remote sensing products, and total runoff. Based on the model output, drought-sensitive parameters, such as the difference between potential and effective stand transpiration (Tdiff) and the water balance, were deduced from the model, analyzed, and evaluated. Results show that the modeled evapotranspiration (ET) correlated significantly (R2 = 0.80) with the estimated ET using MODIS data (MOD16A2GFv006). Compared with observed daily, monthly, and annual runoff data, the model shows a good performance (R2: 0.70|0.77|0.73; Kling–Gupta efficiency: 0.59|0.62|0.83; volumetric efficiency: 0.52|0.60|0.83). The comparison with in situ data from a forest monitoring plot, established at the end of 2020, indicated good agreement between observed and simulated interception and soil water content. According to our results, WaSiM-ETH is a potential supplement for forest management, owing to its multidimensionality and the ability to model soil water balance for large areas at comparable high spatial resolution. The outputs offer, compared to non-distributed models (like LWF-Brook90), spatial differentiability, which is important for small-scale parceled forests, regarding stand structure and soil properties. Due to the spatial component offered, additional verification possibilities are feasible allowing a reliable and profound verification of the model and its parameterization. KW - forest ecology KW - forest hydrology KW - WaSiM-ETH KW - drought stress indicators KW - beech Y1 - 2023 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-357358 VL - 6 ER - TY - JOUR A1 - Schulz, Erhard A1 - Joseph, Alain A1 - Baumhauer, Roland A1 - Schultze, Ekkerhard A1 - Sponholz, Barbara T1 - Upper Pleistocene and Holocene history of the Bilma region (Kawar, NE-Niger) T1 - Evolution de la region de Bilma (Kawar, NE-Niger) au Pleistocene superier et a l'Holocene N2 - A 42 m drilling was pertormed in the depresalon of Bilma, Xawar, NE-Niger. The sediment and pollen records show that after an initial deposition of dune sands there were repeated lake phases which terminated by desiccation and consolidation of spring mounds. The pollen record indicates a continuous presence of savanna vegetation. The record probably covers the period between the Upper Pleistocene and the Late Holocene. The climate was characterised by a monssonal summer rain regime giving effective rain fall of about 450-500 mm per year. Groundwater recharge was possible but estimates of the amount of water resources are difficult because of the karstic system of the escarpment and the nearly unknown hydrogeological situation. N2 - Dans la dépression de Bilma, Kawar, NE-Niger, un forage de 42 m a été réalisé. La séquence couvre la période entre le Pléistocene supérieur et l'Holocéne tardif. Apres une phase initiale de dépôts des sables dunaires, trois phases lacustres sont visibles, chaque fois terminées par une période de dessiccation et formation de dépôts de sources en buttes. Les invertigations polliniques montrent que, pendant toute la période, une végétation de savane était dominante. Le paléoclimat était caractérisé par un régime de mousson et des précipitations effectives d'environ 450-500 mm par an ainsi que des invasions de dépressions atlantiques. Une recharge de la nappe phréatique était possible, mais la connaissance insuffisante de l'hydrologéologie et du systeme karstique rend une estimation des ressources en eau tres difficile. KW - Pleistozän KW - Holozän KW - Bilma Y1 - 1990 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-86828 ER - TY - JOUR A1 - Meister, Julia A1 - Garbe, Philipp A1 - Trappe, Julian A1 - Ullmann, Tobias A1 - Es-Senussi, Ashraf A1 - Baumhauer, Roland A1 - Lange-Athinodorou, Eva A1 - El-Raouf, Amr Abd T1 - The Sacred Waterscape of the Temple of Bastet at Ancient Bubastis, Nile Delta (Egypt) JF - Geosciences N2 - Sacred water canals or lakes, which provided water for all kinds of purification rites and other activities, were very specific and important features of temples in ancient Egypt. In addition to the longer-known textual record, preliminary geoarchaeological surveys have recently provided evidence of a sacred canal at the Temple of Bastet at Bubastis. In order to further explore the location, shape, and course of this canal and to find evidence of the existence of a second waterway, also described by Herodotus, 34 drillings and five 2D geoelectrical measurements were carried out in 2019 and 2020 near the temple. The drillings and 2D ERT surveying revealed loamy to clayey deposits with a thickness of up to five meters, most likely deposited in a very low energy fluvial system (i.e., a canal), allowing the reconstruction of two separate sacred canals both north and south of the Temple of Bastet. In addition to the course of the canals, the width of about 30 m fits Herodotus’ description of the sacred waterways. The presence of numerous artefacts proved the anthropogenic use of the ancient canals, which were presumably connected to the Nile via a tributary or canal located west or northwest of Bubastis. KW - ancient Egypt KW - Tell Basta KW - sacred lakes KW - Herodotus KW - ERT KW - drilling KW - Isheru Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-246129 SN - 2076-3263 VL - 11 IS - 9 ER -