Uncertainties and shortcomings of ground surface temperature histories derived from inversion of temperature logs

Analysing borehole temperature data in terms of ground surface history can add useful information to reconstructions of past climates. Therefore, a rigorous assessment of uncertainties and error sources is a necessary prerequisite for the meaningful interpretation of such ground surface temperature histories. This study analyses the most prominent sources of uncertainty. The diffusive nature of the process makes the inversion relatively robust against incomplete knowledge of the thermal diffusivity. Similarly the influence of heat production is small. It turns out that for investigations of the last 1000 to 100000 years the maximum depth of the temperature log is crucial. More than 3000 m are required for an optimal inversion. Reconstructions of the last one or two millennia require only modestly deep logs (>300 m) but suffer severely from noisy data.Comment: 28 pages, 18 figure, 3 table

Spider fauna of semi-dry grasslands on a military training base in Northwest Germany (Münster)

The spider fauna of semi-dry grasslands on the military training area of Dorbaum near Münster (North Rhine-Westphalia) was investigated. From 2002 to 2003 a total of 11,194 mature spiders from 141 species and 20 families was caught by pitfall trapping and hand sampling. Among them are 18 species listed in the Red Data Book of North Rhine-Westphalia, four species are rare or previously rarely recorded. Most of the spiders are habitat generalists that extend their occurrence into all types of habitats, while the number of species which are stenotopic to sand habitats is noticeably low (n = 13). The spider data were analysed with Principal Component Analysis (PCA). It is possible to distinguish spider communities of neighbouring forested habitats from species groups of open habitats, but there is no uniform spider community which is characteristic for semi-dry grassland

Bericht zur AraGes-Tagung 2010 und zur 5. Mitgliederversammlung der Arachnologischen Gesellschaft von 17. bis 19. September 2010 in Berlin

Der 200. Geburtstag des Museums für Naturkunde Berlin war ein gebührender Anlass, das diesjährige Treffen der deutschsprachigen Arachnologen in diesen „historischen Gemäuern“ stattfinden zu lassen. Der Einladung des Organisationsteams rund um Jason Dunlop folgten erfreulicherweise mehr als 60 Spinnenfreunde aus Albanien, Dänemark, Deutschland, Österreich, Serbien und der Schweiz

Metadata Hub - One for All

The Metadata Hub provides a generic service for metadata repositories. Based on this, different kinds of metadata repositories can be accessed with uniform tools without the researchers having to deal with the complex details. In the domain of research data management, there are a variety of repositories that offer metadata management services to researchers. This poses the challenge that these repositories usually have different interfaces and in nature are not very interoperable with each other, violating one of the FAIR Principles. Our work aims to build a bridge between these repositories as a generic service for metadata repositories, the Metadata Hub. It’s accessible via the Turntable API, which defines a uniform interface for metadata repositories. To validate metadata documents, a definition of the document structure has to be available. For JSON/XML, there is JSON/XML Schema for this purpose. In case of JSON-LD, JSON Schema is not sufficient. Therefore, so-called application profiles are used, which are defined by using Shapes Constraint Language (SHACL). In general, the Turntable API is split in two parts: The first part is about managing (CRUD) ‘schemas/application profiles’ which are describing the structure of metadata documents, extended by the ability to validate a metadata document against a registered ‘schema/application profile/…’. The second part is about managing the metadata documents itself based on one of registered ‘schemas/application profiles’. Currently, we build the Metadata Hub as a Demonstrator mapping two completely different repositories (Coscine, MetaStore) as a showcase. The Metadata Hub is powered by the Metadata Hub Framework and provides a web interface to make the service available to a broad mass. This work has been supported by the research program ‘Engineering Digital Futures’ of the Helmholtz Association of German Research Centers, the Helmholtz Metadata Collaboration Platform and the German National Research Data Infrastructure (NFDI)

Thermal Conductivity from Core and Well log Data

The relationships between thermal conductivity and other petrophysical properties have been analysed for a borehole drilled in a Tertiary Flysch sequence. We establish equations that permit us to predict rock thermal conductivity from logging data. A regression analysis of thermal conductivity, bulk density, and sonic velocity yields thermal conductivity with an average accuracy of better than 0.2 W/(m K). As a second step, logging data is used to compute a lithological depth profile, which in turn is used to calculate a thermal conductivity profile. From a comparison of the conductivity-depth profile and the laboratory data it can be concluded that thermal conductivity can be computed with an accuracy of less than 0.3 W/(m K)from conventional wireline data. The comparison of two different models shows that this approach can be practical even if old and incomplete logging data is used. The results can be used to infer thermal conductivity for boreholes without appropriate core data that are drilled in a similar geological setting.Comment: 18 pages, 9 figure, 3 table

MetaStore - Managing Metadata for Digital Objects

MetaStore is a metadata repository for managing metadata documents. It supports communities in storing metadata documents in a predefined schema. It is therefore an important building block for more precise automated evaluation and/or retrieval of digital objects. With the help of the metadata documents, digital objects can also be evaluated/compared according to content-related aspects. XML and JSON are very common as data formats for such machine-interpretable documents. However, they are only meaningful if they adhere to a certain structure and are correctly filled in. MetaStore supports the use of XML and JSON schema as the definition for the document structure. It allows you to register your own and/or existing schemas in these two formats to ensure that the documents have the appropriate structure. When ingesting metadata documents, the structure is checked and invalid documents are rejected. All valid documents are assigned a persistent identifier and can be automatically indexed for search. Public documents can be harvested via a standardized protocol (OAI-PMH). The supplied web interface also provides a low-threshold entry point for managing documents and also allows documents to be created/edited without additional tools. This work has been supported by the research program ‘Engineering Digital Futures’ of the Helmholtz Association of German Research Centers and the Helmholtz Metadata Collaboration Platform