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Steinau an der Strasse, Germany

Neitzel F.,Mainz University of Applied Sciences | Neitzel F.,Ohio State University
Journal of Geodesy

In this contribution it is shown that the so-called "total least-squares estimate" (TLS) within an errors-in-variables (EIV) model can be identified as a special case of the method of least-squares within the nonlinear Gauss-Helmert model. In contrast to the EIV-model, the nonlinear GH-model does not impose any restrictions on the form of functional relationship between the quantities involved in the model. Even more complex EIV-models, which require specific approaches like "generalized total least-squares" (GTLS) or "structured total least-squares" (STLS), can be treated as nonlinear GH-models without any serious problems. The example of a similarity transformation of planar coordinates shows that the "total least-squares solution" can be obtained easily from a rigorous evaluation of the Gauss-Helmert model. In contrast to weighted TLS, weights can then be introduced without further limitations. Using two numerical examples taken from the literature, these solutions are compared with those obtained from certain specialized TLS approaches. © 2010 Springer-Verlag. Source

Muller H.,Mainz University of Applied Sciences
International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences - ISPRS Archives

For many years FIG, the International Association of Surveyors, has been trying to bridge the gap between surveyors and the geospatial society as a whole, with the geospatial industries in particular. Traditionally the surveying profession contributed to the good of society by creating and maintaining highly precise and accurate geospatial data bases, based on an in-depth knowledge of spatial reference frameworks. Furthermore in many countries surveyors may be entitled to make decisions about land divisions and boundaries. By managing information spatially surveyors today develop into the role of geo-data managers, the longer the more. Job assignments in this context include data entry management, data and process quality management, design of formal and informal systems, information management, consultancy, land management, all that in close cooperation with many different stakeholders. Future tasks will include the integration of geospatial information into e-government and e-commerce systems. The list of professional tasks underpins the capabilities of surveyors to contribute to a high quality geospatial data and information management. In that way modern surveyors support the needs of a geo-spatial society. The paper discusses several approaches to define the role of the surveyor within the modern geospatial society. Source

Nunn E.V.,University of Plymouth | Nunn E.V.,Mainz University of Applied Sciences | Price G.D.,University of Plymouth
Palaeogeography, Palaeoclimatology, Palaeoecology

The data presented here provide the first detailed stable isotope (δ18O, δ13C) and geochemical (Mg/Ca) investigation of Kimmeridgian-Tithonian belemnites from the Helmsdale Coast, Scotland, UK. Oxygen and carbon stable isotope values from well preserved specimens range from -2.8 to +0.3% and from -2.3 to +2.8% respectively. The oxygen isotope data are consistent with palaeotemperatures of up to 24°C in the Early Kimmeridgian cymodoce Zone and down to 11°C in the Mid Tithonian rotunda-fittoni Zones. These estimates are strongly supported by the Mg/Ca data, which also indicate a cooling episode (and very similar palaeotemperatures, 11-22°C) at this time. The cooling event is associated with an approximately 5% decline in δ13C ratios. This shift towards more negative δ13C values has also been recorded in the Tethys and on the Russian Platform, confirming that this event was of global origin. Such globally synchronous records can provide a valuable tool for stratigraphic correlation. The Helmsdale δ13C data are therefore combined here with other published belemnite isotope data from the Jurassic of Scotland (from the Callovian-Kimmeridgian of the Isle of Skye and the Toarcian-Aalenian of Raasay). The resultant belemnite δ13C curve provides a detailed record of the Toarcian-Tithonian British Boreal Realm that can be compared with coeval records to investigate regional differences in Jurassic carbon isotope stratigraphy. © 2010 Elsevier B.V. All rights reserved. Source

Wanamaker A.D.,Iowa State University | Kreutz K.J.,University of Maine, United States | Schone B.R.,Mainz University of Applied Sciences | Introne D.S.,University of Maine, United States
Palaeogeography, Palaeoclimatology, Palaeoecology

In this study, we use subannually resolved oxygen isotope values of fossil (dead-collected) and modern (live-caught) bivalve shells (Arctica islandica L.) from the northwestern Atlantic (Gulf of Maine, USA) to reconstruct past seasonal changes in seawater temperature. Our results indicate decreased seasonal temperature amplitude of about 1.6 °C (or ~. 21%) during Medieval times (ca. AD 1033-1062) compared to shells from the early Little Ice Age (ca. AD 1321-1391) and during the late 19th century (AD 1864-1886). Additionally, seasonal oxygen isotope data suggest that summers were cooler and winters were warmer in the Gulf of Maine during the 11th century compared to summers and winters in the 14th century and the late 19th century. The inferred decreased seasonality during Medieval times likely resulted from increased stratification of the coastal waters due to warmer seawater temperatures. As seawater cooled during the Little Ice Age, we suggest that increased vertical mixing of the coastal surface waters was a major driving factor for the observed increase in the amplitude of the seasonal seawater temperature cycle. © 2010 Elsevier B.V. Source

Schone B.R.,Mainz University of Applied Sciences | Wanamaker A.D.,Iowa State University | Fiebig J.,Goethe University Frankfurt | Thebault J.,University of Western Brittany | Kreutz K.,University of Maine, United States
Palaeogeography, Palaeoclimatology, Palaeoecology

The ability of the ocean to absorb carbon dioxide is likely to be adversely affected by recent climate change. However, relatively little is known about the spatiotemporal variability in the oceanic carbon cycle due to the lack of long-term, high-resolution dissolved inorganic carbon isotope (δ13CDIC) data, especially for the temperate North Atlantic, which is the major oceanic sink for anthropogenic CO2. Here, we report shell carbon isotope values (δ13Cshell), a potential proxy for δ13CDIC, of old-grown specimens of the long-lived bivalve mollusk, Arctica islandica. This paper presents the first absolutely dated, annually resolved δ13Cshell record from surface waters of the North Atlantic (Iceland, Gulf of Maine) covering the time interval between 1753 and 2003. According to our results, the δ13Cshell data were unaffected by trends related to ontogenetic age. However, the shell carbonate was precipitated with a constant offset from expected equilibrium by -1.54 to -2.7±0.2‰ corresponding to a 6.2 to 10.8±0.8% contribution of respiratory CO2 (-25‰). The offset did not appear to vary through the lifetime of individual specimens and among specimens. Therefore, the δ13Cshell data of this species can very likely be used as a measure of δ13CDIC.Furthermore, shell stable carbon isotope chronologies exhibited habitat-specific differences and a significant inter-annual and decadal variability related to the natural carbon cycle. In addition, a distinct negative δ13Cshell shift was found reflecting the oceanic Suess effect, i.e. the admixture of anthropogenic CO2. However, this shift only occurred after the early 1920s when a major climate regime shift led to a northward movement of the oceanic Polar Front in the Nordic Seas and a large-scale reorganization of atmospheric and oceanic currents in the North Atlantic. This likely resulted in a reduced admixture of cold Polar water onto the North Icelandic shelf (through the East Iceland Current) and the Gulf of Maine (through the Labrador Current) with an increased volume of warmer, isotopically well-equilibrated Atlantic waters. Our shell-based δ13CDIC proxy record provides the basis to quantitatively assess natural and anthropogenically induced patterns of carbon uptake in the North Atlantic. © 2010 Elsevier B.V. Source

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