Natural environmental changes and human impact reflected in sediments of a high alpine lake in Switzerland   总被引：1，自引：0，他引：1  

C. Ohlendorf  M. Sturm  S. Hausmann 《Journal of Paleolimnology》2003,30(3):297-306

From the high alpine Sägistalsee (1935 m a.s.l.), 13.50 m of continuously laminated sediments comprising the last 9050 years, were analyzed. Even though Sägistalsee is a high elevation site, human-induced environmental changes start as early as 4300 cal. BP and leave a clearly detectable signal in the mineralogy of the sediments, which is much stronger than the signal from natural environmental changes that occurred before this time. Variations in the physical and mineralogical sediment properties of this clastic sequence reflect erosional changes in the catchment, where almost pure limestone contrasts with carbonaceous, quartz-bearing marl, and shist. The calcite/quartz (Cc/Qz) ratio was found to be most indicative of these changes, which occurred around AD 1850 and at 650, 2000, 3700, and 6400 cal. BP. The first four are interpreted as erosion events, which are related to human-induced changes in the vegetation cover and land use. We associate them to the recent development of tourism and grazing, the medieval intensification of pasturing, Roman forest clearance, and Bronze Age forest clearance, respectively. The Cc/Qz-ratio increases significantly within less than 100 years during these events, reflecting the erosion of unweathered or poorly weathered soils. The time intervals in between are characterized by a gradually decreasing Cc/Qz-ratio and reflect the stabilization or formation of new soils. Only the change at 6400 cal. BP, which represents the initial gradual stabilization of the catchment, is related to the immigration of Picea abies.  相似文献   

Use of accessory zircon for the quantification of volume changes in ductile shear zones cutting plutonic rocks     

Robert Sturm  Hans Peter Steyrer 《Chemie der Erde / Geochemistry》2003,63(1):31-54

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On reducing ambiguity in the interpretation of transient electromagnetic sounding data1     

M. Goldman  A. Du Plooy  M. Eckard 《Geophysical Prospecting》1994,42(1):3-25

An attempt to resolve non-uniqueness in the interpretation of transient electromagnetic (TEM) sounding data using measured data alone is made. It is shown in the various examples studied that sufficiently early time measurements can be the determining factor in reducing the ambiguity caused by model equivalence. The early delay times thus play a dual role in transient soundings: they are responsible for resolving shallow structures and they may eliminate the ambiguity in the interpretation of geoelectric parameters of deeper targets. This is illustrated by the results of a follow-up TEM survey at the Dead Sea coast of Israel where the use of supplementary early time measurements allowed non-uniqueness in the determination of the depth to fresh/saline groundwater interface to be resolved.  相似文献   

Soil moisture variation and plant water stress at the Hartheim Scots pine plantation     

N. Sturm  S. Reber  A. Kessler  J. D. Tenhunen 《Theoretical and Applied Climatology》1996,53(1-3):123-133

Summary During two measurement campaigns in 1992 (the Hartheim Experiment HartX- and an additional experiment in autumn), measurements of soil moisture were carried out in aPinus sylvestris stand at Hartheim on the Oberrhein. Several methods were used to determine soil water status. They were compared in terms of suitability for estimating stand evapotranspiration (ET) via soil water depletion. Measurements of tree water potential suggested that conductance of the trees was affected by soil water depletion during the period of the HartX campaign in spring 1992. We interpret the observations to indicate a lesser influence of soil water availability on tree transpiration during the autumn experiment.Eddy correlation and xylem sapflow measurements provided reference ET values with which to compare the stand ET calculations based on soil moisture measurements. Profile measurements of soil moisture showed that particularly in springtime when the lower soil layers are saturated with water, the water transport from depths below the major rooting zone is a very important factor affecting evaluation of stand ET. Decreases in soil water storage may be determined best with permanently installed soil moisture sensors such as used in tensiometric or TDR measurements that provide high resolution of changes over time.With 8 Figures  相似文献   

Kurzperiodische interne Wellen des Meeres als Folge kleinräumiger kurzzeitig wirksamer äußerer Kräfte     

Dr. Eckard Hollan 《Ocean Dynamics》1972,25(1):14-37

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Sedimentation in Proval Bay (Lake Baikal) after catastrophic flooding of the coastal plain in 1862     

E. G. Vologina  I. A. Kalugin  Yu. N. Osukhovskaya  M. Sturm  N. V. Ignatova  Ya. B. Radziminovich  A. V. Dar’in  M. I. Kuz’min 《Doklady Earth Sciences》2007,417(2):1315-1319

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Influence of catchment quality and altitude on the water and sediment composition of 68 small lakes in Central Europe     

Beat Müller  André F. Lotter  Michael Sturm  Adrian Ammann 《Aquatic Sciences - Research Across Boundaries》1998,60(4):316-337

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Ein Cluster-Verfahren zur richtungsstatistischen Analyse tektonischer Daten     

Dr. Eckard Wallbrecher 《International Journal of Earth Sciences》1978,67(3):840-857

Zusammenfassung Es wird ein Cluster-Verfahren vorgestellt, mit dem in einer Menge von Richtungsdaten die Einzelwerte mit Hilfe eines vorgegebenen variablen Trennmaßes zu verschiedenen Gruppen zusammengefaßt werden. Richtungsstatistische Parameter werden für jede Gruppe berechnet. Außerdem wird ein Signifikanztest für die Trennung der Gruppen voneinander durchgeführt.

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A cluster algorithm for orientation data is presented. It separates groupes of neighboring data by the use of a variable measure of separation. Statistical orientation parameters are calculated for each group and a significance test for the separation of the groups is carried out.

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Résumé Un algorithme pour l'analyse des groupes de vecteurs est présenté. Il sépare des groupes de données voisines en utilisant une mesure variable de séparation. Des paramètres statistiques d'orientation sont calculés pour chacun d'eux, et un test de signification pour séparation des groupes est effectué.

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Natural disasters as the end of the insurance industry? Scalar competitive strategies, Alternative Risk Transfers, and the economic crisis   总被引：1，自引：0，他引：1  

Tristan Sturm  Eric Oh 《Geoforum》2010,41(1):154-163

The aftermath of Hurricane Katrina has piqued interest in the insurance industry, and this scrutiny has led to assumptions that the industry has become unstable and unprofitable with the increased incidence of disasters in highly-insured regions of the world. This paper challenges that assumption by arguing that the insurance industry has responded by spreading risk through scaled and networked recovery schemes. We found that because of competitive strategies of risk-spreading and displacement arrangements, the industry has actually profited as a whole. Regional insurance companies have always relied on the higher financial scales of the reinsurance industry in Munich, Zurich, and London. But with claims reaching into the billions of dollars, the reinsurance industry itself has raised premiums, spread risk farther afield, and jumped scale by spreading risk to futures markets called Alternative Risk Transfers (ARTs). However, the recession beginning in 2008 has called into question the viability of using futures markets as insurance. It is shown through a media analysis of four major business publications (The Economist, The New York Times, The Financial Times and The Wall Street Journal) how the industry responded to the costs of the 2004, 2005, and 2006 hurricane seasons. Because geography is rather new to this literature, this paper also offers a broad review of the insurance industry.  相似文献   

Mrk 1014: an AGN-dominated ultraluminous infrared galaxy     

Th. Boller  L. C. Gallo  D. Lutz  E. Sturm 《Monthly notices of the Royal Astronomical Society》2002,336(4):1143-1146

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