Some remarks on the history of Wingst Geomagnetic Observatory during the first 50 years

Summary For the reason of the 50th anniversary of the Wingst Geomagnetic Observatory of the Deutsches Hydrographisches Institut celebrated on the 30th April 1988, the development of this Observatory and its activities on the background of the social and scientific occurrences during the last 50 years are presented. Contributions of the Observatory to theKp index, the research about the North German conductivity anomaly, geomagnetic measurements at sea, and the application of proton magnetometers as well as other geomagnetic instruments are described.

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Einige Bemerkungen zur Geschichte des Erdmagnetischen Observatoriums Wingst in den ersten 50 Jahren

Zusammenfassung Aus Anlaß des 50jährigen Bestehens des Erdmagnetischen Observatoriums Wingst des Deutschen Hydrographischen Instituts am 30. April 1988 werden die Entwicklung dieses Observatoriums und die dort getane Arbeit vor dem Hintergrund der gesellschaftlichen und wissenschaftlichen Ereignisse von 1938 bis 1988 dargestellt. Beiträge des Observatoriums zur planetarischen KennzifferKp, zur Forschung an der norddeutschen Leitfähigkeitsanomalie, zu erdmagnetischen Messungen auf See und zur Anwendung der Protonenmagnetometer sowie anderer erdmagnetischer Instrumente werden beschrieben.

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Quelques remarques sur les cinquante ans d'histoire de l'observatoire géomagnétique de Wingst

Résumé Le développement et les activités de l'observatoire de géomagnétisme du Deutsches Hydrographisches Institut à Wingst sont évoqués à l'occasion de son cinquantenaire, sur la toile de fond constituée par les évènements sociaux et scientifiques du demi-siècle qui vient de s'écouler.Les contributions de l'observatoire à la détermination du coefficientKp, utilisé pour décrire l'activité géomagnétique de la planète, les recherches relatives à l'anomalie de conductivité en Allemagne du Nord, les mesures de magnétisme à la mer ainsi que les applications des magnétomètres à protons et d'autres appareils de mesures géomagnétiques sont également décrites.

     

Solar evolution and the distant future of Earth

Peter Schröder, Robert Smith and Kevin Apps take a speculative look at what the future may hold as the Sun becomes a supergiant.
Astronomy textbooks tell us that one day the Sun will expand to become a red supergiant of enormous size, finally swallowing its inner planets, including Earth. However, recent solar evolution models, which account for a realistic amount of mass loss, suggest a (slightly) less catastrophic future for our planet.     

Thermal evolution of the Earth: Secular changes and fluctuations of plate characteristics

The average secular cooling rate of the Earth can be deduced from compositional variations of mantle melts through time and from rheological conditions at the onset of sub-solidus convection at the end of the initial magma ocean phase. The constraint that this places on the characteristics of mantle convection in the past are investigated using the global heat balance equation and a simple parameterization for the heat loss of the Earth. All heat loss parameterization schemes depend on a closure equation for the maximum age of oceanic plates. We use a scheme that accounts for the present-day distribution of heat flux at Earth's surface and that does not depend on any assumption about the dynamics of convection with rigid plates, which remain poorly understood. We show that heat supply to the base of continents and transient continental thermal regimes cannot be ignored. We find that the maximum sea floor age has not changed by large amounts over the last 3 Ga. Calculations lead to a maximum temperature at an age of about 3 Ga and cannot be extrapolated further back in time. By construction, these calculations are based on the present-day tectonic regime characterized by the subduction of large oceanic plates and hence indicate that this regime did not prevail until an age of about 3 Ga. According to this interpretation, the onset of rapid continental growth occurred when the current plate regime became stable.     

地磁房湿度对地磁观测的影响及解决方案

地磁房湿度变化较快或过大都易引起地磁数据的异常变化,且室内湿度不易控制,地磁房、磁通门磁力仪探头湿度智能在线分析监控系统,可以实时显示监控地磁房、磁通门磁力仪探头湿度的变化,超过湿度阈值则发出报警信号,进而可以采用科学的方法控制探头观测环境的湿度,提高观测数据的稳定性、可靠性。本文介绍了该系统的设计思路和主要功能。     

Regionalized models for the thermal evolution of the Earth

Traditional models for the heat loss in oceanic and continental regions are combined into a regionalized model for the thermal evolution of the Earth. The need for regionalization is obvious when one considers that the mantle loses 3 to 4 times as much heat per unit area in oceanic regions than in continental areas. The present-day rate of heat loss together with a geochemical estimate of the concentration of heat-producing elements in the Earth fixes the response time of the thermally convecting mantle. The response time in turn can be used to select the most reasonable representation for mantle convection in terms of the sensitivity of viscosity on temperature and layering versus mantle-wide circulation. Present geochemical estimates of the bulk composition of the Earth are most easily reconciled with the observed heat flow if the mantle is layered and its rheology is slightly less temperature dependent than generally assumed. The layered system can produce sufficiently high temperatures to explain the high-magnesian komatiites of the Archean. One difficulty with the models is that they predict widespread melting at shallow depth in the early stages of Earth history but do not address how such melting affects and alters the heat transfer mechanisms.     

Enhancing remote sensing research on global change to improve our understanding on Earth system processes

正Global Change includes climate change and other environmental changes caused by the joint interaction among various layers of Earth. From the positive side, global change provides new opportunities to human and other living forms on Earth. In the meantime, it creates tremendous challenges and negative impact. At present, the negative impacts have reached all primary processes of the global ecosystem and every aspect of human society, especially causing degradation of the ecosystem. For instance, intensive deforestation causes decline of biodiversity; global warming causes sea level rise and increases     

Correction to: A Dynamical Prospective on Interannual Geomagnetic Field Changes

Surveys in Geophysics -     

Mineral photoelectrons and their implications for the origin and early evolution of life on Earth

Energy is the key issue of all life activities.The energy source and energy yielding pathway are the key scientific issues of the origin and early evolution of life on Earth.Current researches indicate that the utilization of solar energy in large scale by life was an important breaking point of the early evolution of life on Earth and afterwards life gradually developed and flourished.However,in the widespread biochemical electron transfer of life activities,it is still not clear whether the electron source is sun or how electrons originated from sun.For billions of years,the ubiquitous semiconducting minerals in epigeosphere absorb solar energy,forming photoelectrons and photoholes.In reductive and weak acidic environment of early Earth,when photoholes were easily scavenged by reducing matters,photoelectrons were separated.Photoelectrons could effectively reduce carbon dioxide to organic matters,possibly providing organic matter foundation for the origin of life.Photoelectrons participated in photoelectron transfer chains driven by potential difference and transfer into primitive cells to maintain metabolisms.Semiconducting minerals,by absorbing ultraviolet,also protected primitive cells from being damaged by ultraviolet in the origin of life.Due to the continuous photoelectrons generation in semiconducting minerals and utilization by primitive cells,photoelectrons from semiconducting minerals’photocatalysis played multiple roles in the origin of life on early Earth,such as organic synthesis,cell protection,and energy supply.This mechanism still plays important roles in modern Earth surface systems.     

多种对地观测技术及Google Earth技术应用于土地利用/覆被变化建库

为克服传统生态环境监测周期长,可靠性差,精度低的局限性,提出利用多种对地观测技术及Google Earth 技术进行土地利用/覆被变化监测方法.即利用新近获取的遥感影像为信息源,以原有的遥感影像解译数据为基础,对新遥感影像进行土地利用/覆被变化解译,修改旧遥感解译数据库;利用Google Earth上具有的高分辨率遥感影像,在室内对解译过程中的不确定地物进行补判;利用手持GPS接收机在野外对解译结果进行核查,并更新数据库;利用GIS空间分析功能,提取出高精度土地利用/覆被变化信息.实验选取近年旱涝灾害严重的四川作为研究对象,研究结果表明利用多种对地观测技术及Google Earth技术可以有效的对土地利用/覆被变化进行动态监测,并对下一步研究方向进行了探讨.     

Co-seismic change of length of day based on the point dislocation theory for a SNREI Earth

We developed a new approach for computing the changes in the length of day (LOD) due to earthquakes from both shear- and tensile-type faults. This approach was based on the point dislocation theory for a SNREI Earth, which was validated by comparing our results with the ones obtained by the normal mode method. We defined two numerical functions that vary with hypocenter depth. These functions allow us to compute the co-seismic change of the trace of the Earth's inertia tensor, and hence the co-seismic LOD change. For future applications, by adding a trace term, we corrected Lambeck's formulas (Lambeck, 1980), which are being commonly used for computing co-seismic LOD change. Finally, the new approach was used to compute the co-seismic LOD change from 1977 to 2011. The results show that the co-seismic trace and the co-seismic J₂ changes contribute to the LOD change with the same magnitude (Gross and Chao, 2006). This means that, unlike other deformation mechanisms, the trace term cannot be neglected when modeling the co-seismic LOD change. The earthquakes from 1977 to 2011 decreased the LOD by about 12 μs, and the rate of decrease was enhanced after the 2004 Sumatra earthquake due to several large earthquakes.     

Bio‐geomorphic effects on tidal channel evolution: impact of vegetation establishment and tidal prism change

The long‐term (10–100 years) evolution of tidal channels is generally considered to interact with the bio‐geomorphic evolution of the surrounding intertidal platform. Here we studied how the geometric properties of tidal channels (channel drainage density and channel width) change as (1) vegetation establishes on an initially bare intertidal platform and (2) sediment accretion on the intertidal platform leads to a reduction in the tidal prism (i.e. water volume that during a tidal cycle floods to and drains back from the intertidal platform). Based on a time series of aerial photographs and digital elevation models, we derived the channel geometric properties at different time steps during the evolution from an initially low‐elevated bare tidal flat towards a high‐elevated vegetated marsh. We found that vegetation establishment causes a marked increase in channel drainage density. This is explained as the friction exerted by patches of pioneer vegetation concentrates the flow in between the vegetation patches and promotes there the erosion of channels. Once vegetation has established, continued sediment accretion and tidal prism reduction do not result in significant further changes in channel drainage density and in channel widths. We hypothesize that this is explained by a partitioning of the tidal flow between concentrated channel flow, as long as the vegetation is not submerged, and more homogeneous sheet flow as the vegetation is deeply submerged. Hence, a reduction of the tidal prism due to sediment accretion on the intertidal platform, reduces especially the volume of sheet flow (which does not affect channel geometry), while the concentrated channel flow (i.e. the landscape forming volume of water) is not much affected by the tidal prism reduction. Copyright © 2012 John Wiley & Sons, Ltd.     

关于数字地磁台站观测系统的发展与观测资料应用的一点思考

针对地球科学和国家建设对地磁观测与研究的需求，结合“九五”地磁台站观测技术数字化改造，对地磁台站观测系统的发展及数字观测资料的应用提出了一些见解。     

The Myasnikov global theory of the evolution of planets and the modern thermochemical model of the Earth’ls evolution

The thermochemical model of the authors is shown to be naturally related to the general theory of V.P. Myasnikov. A heterogeneous modification of this homogeneous theory is described in light of the present ideas on the differentiation of the mantle substance at the boundary with the core and its eclogitization during submersion from the outer boundary and at the endothermic phase transition at a depth of 670 km. The Earth’ls evolution from an initial hot state is numerically modeled. The evolution is shown to start with an abrupt mantle overturn followed by a long period of steady evolution. Global mantle overturns recur a few times, gradually weaken, and are transformed into regional avalanches. The spatial configuration of overturns is represented by a predominant funnel-shaped sink and a few (three to five) ascending superplumes, which convincingly explains the causes of the formation of supercontinents, the opening of oceans, and the observed asymmetry of the planet. The times of overturns remarkably correlate with geological data on the existence of supercontinents. The processes of core growth, mantle cooling, and crust formation exhibit a clearly expressed stepwise behavior. The supplementation of the endothermic phase transition by chemical transformations favors the overcoming of the phase barrier between the upper and lower mantle, enhances the nonlinearity of mantle convection, and imparts a heterocyclic pattern to the process of evolution. It is shown that the lower mantle plume of chemical origin is fragmented by the phase transition into parts that, interacting with the thermal convection, generate a system of upper mantle plumes. This modeling provides an explanation of the coeval systems of oceanic plateaus and continental traps observed on the surface.     

115 years of sediment deposition in a reservoir in Central Europe: Topographic change detection

Reservoirs have become an important component in the worldwide river sediment flux. Reservoirs prevent downstream sediment transport and have become a major sediment sink. In this study, sediment deposition during the last 115 years in the Urft Reservoir in western Germany is reconstructed. The Urft Reservoir is the oldest reservoir in the Eifel Mountains and was almost completely drained in 2020. This enabled a detailed mapping of the lake bottom using an unmanned aerial system and the computation of a high-resolution digital surface model. Topographic maps with a nominal resolution of 1:1000 from the time prior to the construction of the dam (around 1900) were used to construct a pre-reservoir elevation model. A digital elevation model of difference (DoD) was calculated from these two datasets for the reservoir floor (0.72 km²). Based on the DoD, a net sediment accumulation of 1.16 × 10⁶ m³ was calculated alongside a propagated volume error of 6.91 × 10⁵ m³, resulting in a mean accumulation of 1.54 m. Conservative vertical error propagation results in an average level of detection (LoD) of 1.8 m. In contrast, the comparison of the DoD with 47 cores in the upper part of the reservoir showed a mean difference of −0.11 m, indicating a high, independently assessed accuracy of the DoD. Three depositional hotspots were identified in the reservoir. One is close to the Urft dam where very fine sediments are draped across the pre-reservoir topography. Two areas are related to reservoir management. Sediment deposition in the Urft Reservoir has been comparably low in comparison to other regions globally, resulting in a 3.25% ± 1.93% loss of reservoir volume between 1905 and 2020. To analyse the effect of strong flooding events, a subset of the reservoir was analysed after an extreme event in July 2021, but accumulation did almost entirely not exceed the LoD.     

青海湖地区环境变化对动物区系演变影响的探讨

青海湖地区近百年来由于气候干暖化趋势增强,湖周植被、土地退化,人类经济活动加剧,湖区青藏高原动物成分的种类和数量减少,但蒙新及华北动物区系成分则有增加趋势,致使该区动物区系成分发生显著变化。从青海湖地区动物区系形成来看,决定动物区系演变的原因主要是气候、生物等生态因子的综合作用,人为因子影响仅在近30年来才日益突出。     

Vicissitude of Sogo Nur and environmental-climatic change during last 1500 years

Lakes in arid zone are sensitive to climatic changes. The lacustrine sediment sequence in Sogo Nur has well and truly recorded climatic events such as the Sui-Tang Dynasty Warm Period, the Song-Liao Dynasty Cold Period, the Medieval Warm Period, the Little Ice Age and the 20th Century Warm Period. Commonly, the climate in warm Periods was relatively humid,accordingly the lake area extended and water level rose, and vice versa. Apart from climatic change, human activity is also an important factor of influencing lake vicissitude, and they played the dominant role alternatively during different periods; the factor of climatic change predominated in historical period, while since the beginning of the 20th century the utilization of water resources by human has became decisive.     

Vicissitude of Sogo Nur and environmental-climatic change during last 1500 years

Lakes in arid zone are sensitive to climatic changes. The lacustrine sediment sequence in Sogo Nur has well and truly recorded climatic events such as the Sui-Tang Dynasty Warm Period, the Song-Liao Dynasty Cold Period, the Medieval Warm Period, the Little Ice Age and the 20th Century Warm Period. Commonly, the climate in warm Periods was relatively humid, accordingly the lake area extended and water level rose, and vice versa. Apart from climatic change, human activity is also an important factor of influencing lake vicissitude, and they played the dominant role alternatively during different periods; the factor of climatic change predominated in historical period, while since the beginning of the 20th century the utilization of water resources by human has became decisive.