Roland Baumhauer

Effect of soil parameters on the corrosion of archaeological metal finds.

Archaeologists have observed an increasing tendency for freshly excavated iron artefacts to deteriorate due to accelerated corrosion. Iron artefacts and associated soil samples from German archaeological sites have therefore been examined and analysed. The approximate aggressiveness of the soil toward buried iron objects has been estimated by means of an existing rating standard. In addition, correlation coefficients have been calculated to investigate the relationship between soil properties and the state of corrosion. The results showed that the most heavily corroded artefacts came from sandy and acidic soils as well as from urban soils. The investigation showed that there is the risk of complete destruction of iron artefacts in well-drained soils with low buffering capacities. Conservation of the archaeological heritage requires the collaboration of soil scientists and metallurgists to develop suitable methods for the protection of buried artefacts.

Land Cover Characterization and Classification of Arctic Tundra Environments by Means of Polarized Synthetic Aperture X- and C-Band Radar (PolSAR) and Landsat 8 Multispectral Imagery — Richards Island, Canada

In this work the potential of polarimetric Synthetic Aperture Radar (PolSAR) data of dual-polarized TerraSAR-X (HH/VV) and quad-polarized Radarsat-2 was examined in combination with multispectral Landsat 8 data for unsupervised and supervised classification of tundra land cover types of Richards Island, Canada. The classification accuracies as well as the backscatter and reflectance characteristics were analyzed using reference data collected during three field work campaigns and include in situ data and high resolution airborne photography. The optical data offered an acceptable initial accuracy for the land cover classification. The overall accuracy was increased by the combination of PolSAR and optical data and was up to 71% for unsupervised (Landsat 8 and TerraSAR-X) and up to 87% for supervised classification (Landsat 8 and Radarsat-2) for five tundra land cover types. The decomposition features of the dual and quad-polarized data showed a high sensitivity for the non-vegetated substrate (dominant surface scattering) and wetland vegetation (dominant double bounce and volume scattering). These classes had high potential to be automatically detected with unsupervised classification techniques.

Remote Sensing of River Delta Inundation: Exploiting the Potential of Coarse Spatial Resolution, Temporally-Dense MODIS Time Series

River deltas belong to the most densely settled places on earth. Although they only account for 5% of the global land surface, over 550 million people live in deltas. These preferred livelihood locations, which feature flat terrain, fertile alluvial soils, access to fluvial and marine resources, a rich wetland biodiversity and other advantages are, however, threatened by numerous internal and external processes. Socio-economic development, urbanization, climate change induced sea level rise, as well as flood pulse changes due to upstream water diversion all lead to changes in these highly dynamic systems. A thorough understanding of a river delta’s general setting and intra-annual as well as long-term dynamic is therefore crucial for an informed management of natural resources. Here, remote sensing can play a key role in analyzing and monitoring these vast areas at a global scale. The goal of this study is to demonstrate the potential of intra-annual time series analyses at dense temporal, but coarse spatial resolution for inundation characterization in five river deltas located in four different countries. Based on 250 m MODIS reflectance data we analyze inundation dynamics in four densely populated Asian river deltas—namely the Yellow River Delta (China), the Mekong Delta (Vietnam), the Irrawaddy Delta (Myanmar), and the Ganges-Brahmaputra (Bangladesh, India)—as well as one very contrasting delta: the nearly uninhabited polar Mackenzie Delta Region in northwestern Canada for the complete time span of one year (2013). A complex processing chain of water surface derivation on a daily basis allows the generation of intra-annual time series, which indicate inundation duration in each of the deltas. Our analyses depict distinct inundation patterns within each of the deltas, which can be attributed to processes such as overland flooding, irrigation agriculture, aquaculture, or snowmelt and thermokarst processes. Clear differences between mid-latitude, subtropical, and polar deltas are illustrated, and the advantages and limitations of the approach for inundation derivation are discussed.

Comparison of spatial modelling and field evidence of glacier/permafrost relations in an Alpine permafrost environment

Abstract According to geographic information system-based modelling, the Muragl glacier forefield situated in the St Moritz area, eastern Swiss Alps, lies in a potential permafrost area. As an attempt to verify spatial modelling, BTS (bottom temperature of the winter snow cover) measurements, geoelectrical soundings and geomorphological mapping were carried out in order to investigate the present-day permafrost and ground-ice distribution in this forefield. Recent geomorphodynamic processes in the steep upper slopes of the cirque include small debris flows and several slides related to the occurrence of ground ice. The occurrence of fluted moraines and a well-developed push moraine provides geomorphological evidence for a complex thermal regime of the former Muragl glacier, with cold marginal parts frozen to the bed, and warm-based ice in more central parts where fluted moraines could develop. Details of the inferred glacier/permafrost interaction are difficult to interpret. The results of field measurements (BTS and geoelectrical soundings) in the recently deglaciated forefield indicate the local occurrence of permafrost in the forefield and in the push moraine. In most parts of the forefield, permafrost may be assumed to be a former subglacial occurrence. However, new permafrost formation in the recently deglaciated forefield cannot be excluded.

Managing the impact of climate change on the hydrology of the Gallocanta Basin, NE-Spain.

The Gallocanta Basin represents an environment highly sensitive to climate change. Over the past 60 years, the Laguna de Gallocanta, an ephemeral lake situated in the closed Gallocanta basin, experienced a sequence of wet and dry phases. The lake and its surrounding wetlands are one of only a few bird sanctuaries left in NE-Spain for grey cranes on their annual migration from Scandinavia to northern Africa. Understanding the impact of climate change on basin hydrology is therefore of utmost importance for the appropriate management of the bird sanctuary. Changes in lake level are only weakly linked to annual rainfall, with reaction times between hours and months after rainfall. Both the total amount of rainfall over the reaction period, as well as individual extreme events, affect lake level. In this study the characteristics and frequencies of daily, event, monthly and bi-monthly rainfall over the past 60 years were analysed. The results revealed a clear link between increased frequencies of high magnitude rainfall and phases of water filling in the Laguna de Gallocanta. In the middle of the 20th century, the absolute amount of rainfall appears to have been more important for lake level, while more recently the frequency of high magnitude rainfall has emerged as the dominant variable. In the Gallocanta Basin, climate change and the distinct and continuing land use change since Spain joined the EU in 1986 have created an environment that is in a more or less constant state of transition. This highlights two challenges faced by hydrologists and climatologists involved in developing water management tools for the Gallocanta Basin in particular, but also other areas with sensitive and rapidly changing environments. Hydrologists have to understand the processes and the spatial and temporal patterns of surface-climate interaction in a watershed to assess the impact of climate change on its hydrology. Climatologists, on the other hand, have to develop climate models which provide the appropriate output data, such as reliable information on rainfall characteristics relevant for environmental management.

Environmental changes in the Central Sahara during the Holocene - The Mid-Holocene transition from freshwater lake into sebkha in the Segedim depression, NE Niger

The change from a fresh water lake to a sebkha during the middle Holocene was investigated in the Segedim depression/North-eastern Niger using continuous thin sections for micropetrography, palynology and for diatoms. This record is clearly divided into several units showing sequences of laminated anoxic to oxic clays, the stage of a sebkha with an inflow of loess, fine broken quartz grains and salts which are covered by dune sands made of rounded and clay covered quartz. The mineral assemblages of the three principal units are defined by the illite/kaolinitecalcite/aragonite-pyrite association (oxic lake), a kaolinite-calcite-halite-anhydrite (anoxic lake) and a montmorillonite-celestine-sodium carbonate-gypsum association connected to the sebkha. The composition of the sediments indicates a remarkable influence of sedimentation (ashes, phytoliths, charcoals, carbonates).

Spatial exposure aspects contributing to vulnerability and resilience assessments of urban critical infrastructure in a flood and blackout context

Blackouts aggravate the situation during an extreme river-flood event by affecting residents and visitors of an urban area. But also rescue services, fire brigades and basic urban infrastructure such as hospitals have to operate under suboptimal conditions. This paper aims to demonstrate how affected people, critical infrastructure, such as electricity, roads and civil protection infrastructure are intertwined during a flood event, and how this can be analysed in a spatially explicit way. The city of Cologne (Germany) is used as a case study since it is river-flood prone and thousands of people had been affected in the floods in 1993 and 1995. Components of vulnerability and resilience assessments are selected with a focus of analysing exposure to floods, and five steps of analysis are demonstrated using a geographic information system. Data derived by airborne and spaceborne earth observation to capture flood extent and demographic data are combined with place-based information about location and distance of objects. The results illustrate that even fire brigade stations, hospitals and refugee shelters are within the flood scenario area. Methodologically, the paper shows how criticality of infrastructure can be analysed and how static vulnerability assessments can be improved by adding routing calculations. Fire brigades can use this information to improve planning on how to access hospitals and shelters under flooded road conditions.

Palaeoenvironmental significance of charophyte gyrogonites from Laguna de Gallocanta (Aragón, Spain)

Abstract At a distance of about 170 km from the Mediterranean, the inland salt lake Laguna de Gallocanta (995 m a.s.l.) is an important stop-over for thousands of migratory water birds and represents an athallasic occurrence of Lamprothamnium papulosum (Wallr.) J. Groves and Chara galioides DC., which were recorded growing in the lake until 1990. These two charophyte species are typically also known from Mediterranean coastal brackish water sites. The material studied here consists of (i) gyrogonites collected from surface sediments in Laguna de Gallocanta and (ii) fossil gyrogonites recovered from the upper 35 cm of a 75 cm core obtained from the lake. Detailed morphological and biometrical analysis of L. papulosum is provided and compared with previous data from South France. The size and shape of the gyrogonites from Laguna de Gallocanta differ greatly from populations growing in coastal sites. These differences are considered to be an adaptive morphological response to the particular hydro-chemical conditions prevailing in Laguna de Gallocanta whose salinity is due to the outwash of sulphate-rich waters from the underground. The distribution and frequency changes of the charophyte species along the core profile allow inferring palaeoecological changes marked by lake-level lowering and increasing salinity.

Critical Parameters for Mass-Cargo Affine Industries Due to Climate Change in Germany: Impacts of Low Water Events on Industry and Possible Adaptation Measures

Most economic models ignore specific information at industry or company level concerning impacts of low water situations on logistic chains and production processes of mass-cargo affine industries. But particularly mass-cargo affine companies are affected by these events, especially regarding their security of supply and transport costs. In order to identify these effects, a survey was conducted. The first results of this survey and of a media analysis on this topic are presented in this publication. The survey included, e.g. the quantity of transported goods, preferred ship sizes, storage capacity, and the perception of sensitivities. Interviewed persons were people in key positions from affected industries (e.g. pharmaceutical and chemical industry, steel production, and hard coal power plants), inland navigation, ports, associations, and research.

Mass-cargo-affine industries and climate change

The impact of low water periods on inland navigation and companies is well known by ship-operators and companies that rely on this mode of transport but it is rarely a topic of climate impact research. As climate change might affect the frequency and intensity of low water periods, quantifying the impact of climate change on companies and the effects of possible adaptation measures is vital. In this study, we present a model for quantifying the impact of low water events on companies which rely on inland navigation and apply that model to three anonymous iron and steel companies along the River Rhine. The deviation of optimal storage, the storage level that evens out risk vs. fixed capital, is used in the model to measure the vulnerability of companies. The results show that, depending on the climate scenario, the companies might have to deal with either one or five additional days of empty storage in the near future (2021–2050) and up to nine more days by the 2071–2100 period. Seasonal analysis shows that, consistent with the change in the river discharge, the biggest deviations from optimal storage level occur in the late summer/early autumn. Analysis of adaptation options shows that companies would need to increase storage capacity by 2.5 % for the 2021–2050 period, and by 25 % by the 2071–2100 period. A reduction of ship sizes is not an adaptation option for the three companies in this study, because these companies already use relatively small vessels. This is however an efficient adaptation option for companies which employ larger vessels for transport. Another adaptation option would be to reduce the share of transportation via inland waters, but the feasibility of this option depends on the availability and cost of other modes of transport.