On Rates and Acceleration Trends of Global Glacier Mass Changes   总被引：4，自引：0，他引：4  

Wilfried Haeberli  Regula Frauenfelder  Martin Hoelzle  & Max Maisch 《Geografiska Annaler: Series A, Physical Geography》1999,81(4):585-591

Worldwide glacier mass changes are considered to represent natural key variables within global climate-related monitoring programmes, especially with respect to strategies concerning early detection of enhanced greenhouse effects on climate. This is due to the fact that glacier mass changes provide important quantitative information on rates of change, acceleration tendencies and pre-industrial variability relating to energy exchange at the earth/athmosphere interface. During the coming decades, excess radiation income and sensible heat (a few watts per square metre) as calculated with numerical climate models are both estimated to increase by a factor of about two to four as compared to the mean of the 20th century. The rate of average annual mass loss (a few decimetres per year) measured today on mountain glaciers in various parts of the world now appears to accelerate accordingly, even though detailed interpretation of the complex processes involved remains difficult. Within the framework of secular glacier retreat and Holocene glacier fluctuations, similar rates of change and acceleration must have taken place before, i.e. during times of weak anthropogenic forcing. However, the anthropogenic influences on the atmosphere could now and for the first time represent a major contributing factor to the observed glacier shrinkage at a global scale. Problems with such assessments mainly concern aspects of statistical averaging, regional climate variability, strong differences in glacier sensitivity and relations between mass balance and cumulative glacier length change over decadal to secular time scales. Considerable progress has recently been achieved in these fields of research.  相似文献   

The effect of flood intermittency on bifurcations in fluviodeltaic systems: Experiment and theory     

Max S. Daniller-Varghese  Wonsuck Kim  David C. Mohrig 《Sedimentology》2020,67(6):3055-3066

The dimensions and organization of deltaic islands and channels dictate delta morphology. This study presents experimental results modelling deposition at a river mouth and flow bifurcation around delta islands. Mouth bar formation and channel bifurcation is achieved in a laboratory setting by alternating input of suspended load transport and bedload transport. These two modes of transport produce two characteristic deposits with different advection lengths. Suspended load transport creates a steep deposit far from the inlet, while bedload creates a low angle, levéed deposit near the inlet. This study found that flow bifurcations occur where the proximal and distal deposits encroach on one another; and determined that there is a relationship between the frequency of suspended load transport and the length to channel bifurcation. Frequent flooding causes shorter length to bifurcations, whereas infrequent flooding causes greater length to bifurcations. This work overturns the hitherto understood mechanism of bifurcation location as a function of only high-transport conditions. Instead, the interactions between the sediment transport and deposition from normal flow and large-scale flooding events dictate delta island morphology.  相似文献   

Robust optical tracking of individual ejecta particles in hypervelocity impact experiments          下载免费PDF全文

Max Gulde  Lukas Kortmann  Matthias Ebert  Erkai Watson  Jakob Wilk  Frank Schäfer 《Meteoritics & planetary science》2018,53(8):1696-1704

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Interactive maps,productivity and user experience: A user study in the e‐mobility domain     

Auriol Degbelo  Jan Kruse  Max Pfeiffer 《Transactions in GIS》2019,23(6):1352-1373

E‐mobility has been gaining importance in recent years in Germany, with the National Platform for E‐mobility infrastructure in Germany is expected to change fast, therefore many charging stations will appear. These need to be managed, and the aim of this work is to explore how web applications could best support productivity and user experience in this context. We compared a text‐form‐based approach to a map‐based approach for the addition and update of locations and chargepoints. We found that the map‐based approach yields better learning effects and offers a better compromise between pragmatic and hedonic properties. The results are useful for a better understanding of the impact of interactive maps on work and user experience in the e‐mobility domain and beyond.  相似文献   

The pre-Caledonian Inishkea Division of northwest Co. Mayo,Ireland: Its geochemistry and probable stratigraphic position     

J. A. Winchester  M. D. Max 《Geological Journal》1987,22(4):309-331

The dominantly metasedimentary schists and gneisses of the Inishkea Division of the Erris Complex form a distinct rock group, structurally overlying the Grenvillian Annagh Division orthogneisses and underlying Dalradian metasediments, in the northwest County Mayo metamorphic inlier. A regression line for the Inishkea Division schists, defined by Rb–Sr whole rock analysis, suggests a metamorphic age of about 800 Ma, with a provenance age of about 1000–1300 Ma. The major and trace element chemistry is distinct from both the Annagh Division and Dalradian rocks, although sometimes similar to that of the Erris Group, and it suggests that the Inishkea Division originated as greywackes with associated intrusives. Local variations of the chemistry exist, but no systematic subdivision of the Division has been made. Amphibolite pods within the schists are metamorphosed and deformed tholeiite dykes, which are similar in chemistry to the younger metadolerites seen in the Annagh Division. While the geochemistry suggests that the Inishkea Division rocks are similar to both the Moine Assemblage and Grampian Group rocks of Scotland, the isotopic data suggest that they may have been deposited and then initially metamorphosed during the interval between the Grenville metamorphism of the Moine Assemblage and the onset of Dalradian and Erris Group deposition.  相似文献   

Pre-Caledonian basement in Ireland and its cover relationships     

M. D. Max  C. B. Long 《Geological Journal》1985,20(4):341-366

Pre-Caledonian basement is exposed in three areas within the Irish orthotectonic Caledonides: 1. In northwest County Mayo the Erris Complex comprises the Annagh Division, which is largely Grenvillian but includes older gneisses, and the Inishkea Division, which is probably equivalent to the older Moines of Scotland. 2. In the northeast Ox Mountains, Rosses Point and Lough Derg inliers there is a granulite fades, dominantly metasedimentary basement which is probably late Grenville in age. 3. Laxfordian and probably older gneisses are seen in the Inishtrahull Platform northeast of Malin Head, County Donegal. In addition, some gneisses within the belt of ‘Connemara migmatites’ in south Connemara may be fragments of allochthonous basement and some high grade metamorphic rocks in the Tyrone Central inlier have been referred to as pre-Caledonian basement, but there is at present no conclusive support for these suggestions. The Ox Mountains succession seen in the Clew Bay region and the southwest and central Ox Mountains is probably not pre-Caledonian basement. Basement in the paratectonic Caledonides is confined to the Cadomian and possibly pre-Cadomian Rosslare Complex (older than 625 Ma) and the nearby late Precambrian (to early Cambrian ?) Cuilenstown Formation in southeast County Wexford. In addition, an unseen block of basement defined by magnetics immediately to the north of the Dingle peninsula of County Kerry is probably of Rosslare Complex affinity. Granulite facies xenoiiths recovered from volcanic rocks of Carboniferous age about 70 km to the west of Dublin, indicate the character of basement there, though its age is not proven. All contacts between basement and Lower Palaeozoic Caledonian cover in the orthotectonic Caledonides are synmetamorphic slide zones and faults and in the paratectonic Caledonides the contacts are either faults, which are often rooted in older mylonites, or are unexposed and presumed to be major structural breaks.  相似文献   

Magnetic crustal character in Central Ireland     

P. Morris  M. D. Max 《Geological Journal》1995,30(1):49-67

The simplest magnetic model for the upper 20 km of crust in central Ireland is of two layers. A thin, weakly magnetic upper layer carrying a number of magnetic bodies that can be related to surface geology overlies a magnetic crustal zone whose gross magnetization increases towards the north. The deeper trace of the lapetus Suture in central Ireland forms the boundary between a more magnetic northern crustal area and a less magnetic southern area. A pre-Carboniferous major dextral offset of this suture boundary occurs in the Limerick area. The suture is traced beneath the Dingle peninsula in the far south-west of Ireland. In east-central Ireland, between the Iapetus Suture and Southern Upland Line, the crust contains a large, south-dipping magnetic body with no surface expression, which produces the Virginia magnetic anomaly. The development of magnetic bodies — in particular, volcanic rocks of Carboniferous age — has been controlled by regional stress patterns. The major volcanic centre at Limerick lies at the intersection of two major Caledonian block fault systems just to the north of the surface trace of the Hercynian Front.  相似文献   

Insights into Holocene relative sea-level changes in the southern North Sea using an improved microfauna-based transfer function     

Juliane Scheder  Friederike Bungenstock  Kristin Haynert  Anna Pint  Frank Schlütz  Peter Frenzel  Achim Wehrmann  Helmut Brückner  Max Engel 《第四纪科学杂志》2022,37(1):71-85

In light of global warming and rising relative sea level (RSL), detailed reconstructions of RSL histories and their controlling processes are essential in order to manage coastal-protection challenges. This study contributes to unravelling Holocene RSL change on the East Frisian North Sea coast in high resolution and with a new approach for the German Bight. For the first time, a transfer function (vertical error: 29.7 cm ? ~11% of the mean tidal range) for RSL change based on a combined training set of benthic foraminifers and ostracods from the back-barrier tidal basin of Spiekeroog is applied to the Holocene record of the back-barrier tidal basin of Norderney. The resulting RSL curve for the Norderney tidal basin is corrected for decompaction and shows a deceleration in RSL rise between 6000 and 5000 cal bp. The smallest possible error envelope (~1 m) results from the good suitability of salt-marsh layers between 5000 and 4000 cal bp. The RSL curve provides an approach towards the closure of the common data gap of peat-based curves for the southern North Sea related to a lack of basal peats in the youngest age range, and verifies regional differences in glacial isostatic adjustment.  相似文献   

The little ice age,Jean M. Grove, 1988, Methuen,London and New York,xxii + 498 pp., $144 (clothbound)     

James B. Benedict  Max Maisch 《Geoarchaeology》1989,4(4):363-365

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