Seasonal and Inter-Annual Climate Forecasting: The New Tool for Increasing Preparedness to Climate Variability and Change In Agricultural Planning And Operations     

Holger Meinke  Roger C. Stone 《Climatic change》2005,70(1-2):221-253

Climate variability and change affects individuals and societies. Within agricultural systems, seasonal climate forecasting can increase preparedness and lead to better social, economic and environmental outcomes. However, climate forecasting is not the panacea to all our problems in agriculture. Instead, it is one of many risk management tools that sometimes play an important role in decision-making. Understanding when, where and how to use this tool is a complex and multi-dimensional problem. To do this effectively, we suggest a participatory, cross-disciplinary research approach that brings together institutions (partnerships), disciplines (e.g., climate science, agricultural systems science, rural sociology and many other disciplines) and people (scientist, policy makers and direct beneficiaries) as equal partners to reap the benefits from climate knowledge. Climate science can provide insights into climatic processes, agricultural systems science can translate these insights into management options and rural sociology can help determine the options that are most feasible or desirable from a socio-economic perspective. Any scientific breakthroughs in climate forecasting capabilities are much more likely to have an immediate and positive impact if they are conducted and delivered within such a framework. While knowledge and understanding of the socio-economic circumstances is important and must be taken into account, the general approach of integrated systems science is generic and applicable in developed as well as in developing countries. Examples of decisions aided by simulation output ranges from tactical crop management options, commodity marketing to policy decisions about future land use. We also highlight the need to better understand temporal- and spatial-scale variability and argue that only a probabilistic approach to outcome dissemination should be considered. We demonstrated how knowledge of climatic variability (CV), can lead to better decisions in agriculture, regardless of geographical location and socio-economic conditions.  相似文献   

Holocene relative sea-level change, isostatic subsidence and the radial viscosity structure of the mantle of northwest Europe (Belgium, the Netherlands, Germany, southern North Sea)   总被引：1，自引：0，他引：1  

Annemiek Vink  Holger Steffen  Lutz Reinhardt  Georg Kaufmann 《Quaternary Science Reviews》2007,26(25-28):3249-3275

A comprehensive observational database of Holocene relative sea-level (RSL) index points from northwest Europe (Belgium, the Netherlands, northwest Germany, southern North Sea) has been compiled in order to compare and reassess the data collected from the different countries/regions and by different workers on a common time–depth scale. RSL rise varies in magnitude and form between these regions, revealing a complex pattern of differential crustal movement which cannot be solely attributed to tectonic activity. It clearly contains a non-linear, glacio- and/or hydro-isostatic subsidence component, which is only small on the Belgian coastal plain but increases significantly to a value of ca 7.5 m relative to Belgium since 8 cal. ka BP along the northwest German coast. The subsidence is at least in part related to the Post-Glacial collapse of the so-called peripheral forebulge which developed around the Fennoscandian centre of ice loading during the Last Glacial Maximum. The RSL data have been compared to geodynamic Earth models in order to infer the radial viscosity structure of the Earth's mantle underneath NW Europe (lithosphere thickness, upper- and lower-mantle viscosity), and conversely to predict RSL in regions where we have only few observational data (e.g. in the southern North Sea). A very broad range of Earth parameters fit the Belgian RSL data, suggesting that glacial isostatic adjustment (GIA) only had a minor effect on Belgian crustal dynamics during and after the Last Ice Age. In contrast, a narrow range of Earth parameters define the southern North Sea region, reflecting the greater influence of GIA on these deeper/older samples. Modelled RSL data suggest that the zone of maximum forebulge subsidence runs in a relatively narrow, WNW–ESE trending band connecting the German federal state of Lower Saxony with the Dogger Bank area in the southern North Sea. Identification of the effects of local-scale factors such as past changes in tidal range or tectonic activity on the spatial and temporal variations of sea-level index points based on model-data comparisons is possible but is still complicated by the relatively large range of Earth model parameters fitting each RSL curve, emphasising the need for more high-quality observational data.  相似文献   

A revised dynamic model for suspended particulate matter (SPM) in coastal areas     

Lars Håkanson 《Aquatic Geochemistry》2006,12(4):327-364

This paper presents a general, process-based model for suspended particulate matter (SPM) in defined coastal areas (the ecosystem scale). The model is based on ordinary differential equations and the calculation time (dt) is 1 month to reflect seasonal variations. The model has been tested using data from 17 Baltic coastal areas of different character and shown to predict mean monthly SPM-concentrations in water and Secchi depth (a measure of water clarity) very well (generally within the uncertainty bands given by the empirical data). The model is based on processes regulating inflow, outflow and internal fluxes. The separation between the surface-water layer and the deep-water layer is not done in the traditional manner from water temperature data but from sedimentological criteria (from the wave base which regulates where wind/wave-induced resuspension occurs). The model calculates the primary production of SPM (within the coastal areas), resuspension, sedimentation, mixing, mineralization and retention of SPM. The SPM-model is simple to apply in practice since all driving variables may be readily accessed from maps or regular monitoring programs. The model has also been extensively tested by means of sensitivity and uncertainty tests and the most important factor regulating model predictions of SPM-concentrations in coastal water is generally the value used for the SPM-concentration in the sea outside the given coastal area. The obligatory driving variables include four morphometric parameters (coastal area, section area, mean and maximum depth), latitude (to predict surface water and deep water temperatures, stratification and mixing), salinity, chlorophyll and the Secchi depth or SPM-concentration in the sea outside the given coastal area. Many of the structures in the model are general and could potentially be used for coastal areas other than those included in this study, e.g., for open coasts, estuaries or areas influenced by tidal variations.  相似文献   

A method for automatic history matching of a compositional reservoir simulator with multipoint flux approximation     

Dmitry Eydinov  Sigurd Ivar Aanonsen  Jarle Haukås  Ivar Aavatsmark 《Computational Geosciences》2008,12(2):209-225

A method for history matching of an in-house petroleum reservoir compositional simulator with multipoint flux approximation is presented. This method is used for the estimation of unknown reservoir parameters, such as permeability and porosity, based on production data and inverted seismic data. The limited-memory Broyden–Fletcher–Goldfarb–Shanno method is employed for minimization of the objective function, which represents the difference between simulated and observed data. In this work, we present the key features of the algorithm for calculations of the gradients of the objective function based on adjoint variables. The test example shows that the method is applicable to cases with anisotropic permeability fields, multipoint flux approximation, and arbitrary fluid compositions.  相似文献   

Petrographie und Diagenese des Stubensandsteines (mittlerer Keuper) aus Tiefbohrungen im Raum Memmingen (Bayern)     

Holger Kulke 《Contributions to Mineralogy and Petrology》1969,20(2):135-163

The “Stubensandstein” (Middle Keuper) of the Memmingen region (Southern Germany) — the detrital deposit of a nearby granitic red-soil area — was investigated sedimentologically, on the basis of three cores from 2,230, 1,930 and 1,420 metres depth. Shale- and marl-layers are intercalated in beds of coarse grained, immature sandstone. The rare carbonate is predominantly early diagenetic dolomite. The most exceptional result of the diagenesis is the formation of a variously composed claymineral association in the porous sandstones: Kaolinite, sudoite, sudoite/montmorillonitemixed-layers and tosudite (a regular 1∶1 sudoite/montm.-mixed-layer). The detrital component of the clay-minerals (illite and illite/montm.-mixed-layers) is preserved more or less unchanged in the shales, marls and argillaceous sandstones. Two main diagenetic phases can be distinguished:

1. The early diagenetic formation of kaolinite out of the solution-products of feldspars in acid environment. Quartz is precipitated in microcrystalline form in the pore space, garnet is partly dissolved.
2. In the course of the Neogen deep burial stage kaolinite becomes unstable and sudoite and sudoite/montm. are newformed; the intensity of this phenomenon depends on depth of burial and rock-permeability. Calcite sporadically crystallizes out of an environment that has become alkaline; adjacent feldspar becomes more or less dissolved and is pseudomorphically replaced by calcite. Al(OH)₃ is thereby released and is fixed in montmorillonite, thus forming the sudoite of the carbonatic horizons, which never contain kaolinite.

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Strain release in relation to focal depth     

Båth  Markus  Duda  Seweryn J. 《Pure and Applied Geophysics》1963,56(1):93-100

Summary The world-wide strain release in relation to focal depth has been calculated for all shocks with magnitude 7 and over for the interval 1918–1952. The strain exhibits a strong maximum in the uppermost 75 km of the earth; it decreases exponentially with depth between 75 and 400 km, with an unimportant minimum corresponding to the asthenosphere low-velocity layer and another minimum at 275 km; after a pronounced minimum between 400 and 475 km it increases again approximately exponentially between 475 and 650 km, after which it drops rapidly to zero. The shape of the strain-depth curve is interpreted in terms of the physical conditions and the intensity of strain accumulation. In particular, the increase between 475 and 650 km is ascribed to a combined effect of temperature and pressure variation with depth with related phase changes and possible changes in composition. The depth curve for the number of shocks is nearly parallel to the strain-depth curve, and the average strain per earthquake shows only an insignificant decrease with depth.

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Zusammenfassung Es wird die Tiefenabhängigkeit der Deformationsauslösung in allen Erdbeben mit Magnitude 7 und darüber, im Zeitraum 1918–1952 untersucht. Die Deformationsauslösung hat ein ausgesprochenes Maximum in den obersten 75 km. Sie nimmt im Tiefenbereich zwischen 75 und 400 km exponential mit der Tiefe ab, wobei sich ein Minimum, das der Schicht mit niedriger Wellengeschwindigkeit entspricht, schwach andeutet, und ein zweites Minimum bei 275 km liegt. Nach einem ausgeprägten Minimum zwischen 400 und 475 km Tiefe, steigt die Deformationsauslösung erneut, etwa exponential, im Tiefenbereich zwischen 475 und 650 km an, und nimmt danach schnell ab. Der Verlauf der Deformationsauslösung in Abhängigkeit von der Tiefe wird an Hand der physikalischen Verhältnisse im Erdkörper, sowie der Intensität der Deformationsaufspeicherung gedeutet. Insbesondere wird der Anstieg zwischen 475 und 650 km einer Änderung der Temperatur und des Druckes mit der Tiefe, bei Phasensprung und möglicher Änderung in der Zusammensetzung des Materials zugeschrieben. Die Tiefenabhängigkeit der Anzahl der Beben und der Deformationsauslösung verlaufen annähernd parallel; die mittlere Deformationsauslösung pro Erdbeben zeigt lediglich eine unbedeutende Abnahme mit der Tiefe.

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Reassignment of the absorption spectra of purple yoderite     

K. Langer  G. Smith  U. Hålenius 《Physics and Chemistry of Minerals》1982,8(3):143-145

Polarized spectra E∥X, E∥Y, and E∥Z of purple yoderite, taken at 295 and 100 K, result in a revised interpretation for the mineral. Major bands at around 16,900 (X>Y?Z), 18,600 (X?Y), and 20,600 cm^?1 (X≈Z>Y) may be attributed to spin-allowed transitions of Mn³⁺ in trigonal bipyramids (A2 or A3). Minor features may be assigned to single ion Fe³⁺. However, charge transfer possibilities for bands at 18,600 and 25,500 cm^?1 in yoderite cannot be ruled out and are discussed. The extremely high intensity of Mn³⁺ spin-allowed bands (?, 216 to 1,900 [1·g-atom^?1·cm^?1]) is attributed to fivefold coordination of the A2 and A3 position and to the covalency of the Mn³⁺-O bonds.  相似文献   

Identification of seismic sources—earthquake or underground explosion: Proceedings of the NATO Advanced Study Institute,Oslo, September, 1980, Series C,Vol. 74. E.S. Husebye and S. Mykkeltveit (Editors). D. Reidel,Dordrecht, 1981, xii + 876 pp., Dfl.195.00, U.S.$98.00, ISBN 90-277-1320-0     

Markus Båth 《Physics of the Earth and Planetary Interiors》1982,27(4):307-308

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Ecological aspects of fin whale and humpback whale distribution during summer in the Norwegian Sea     

Leif Nøttestad  Lise D. Sivle  Bjørn A. Krafft  Lise Langård  Valantine Anthonypillai  Matteo Bernasconi  Herdis Langøy  Bjørn E. Axelsen 《Marine Ecology》2014,35(2):221-232

The Norwegian Sea is a migration and feeding ground for fin whales (Balaenoptera physalus) and humpback whales (Megaptera novaeangliae) in summer. During the last decade, significant structural changes in the prey community, including northerly expansion and movement in the distribution of pelagic fish species, have been reported from this ecosystem. However, little information on whale feeding ecology exists in the Norwegian Sea and surrounding waters. A total of 59 fin whales and 48 humpback whales were sighted during 864 h of observation over an observation distance of about 8200 nmi (15,200 km) in the Norwegian Sea from 15 July to 6 August 2006 and 2007. The fin whale group size, as mean (±SD), varied between one and five individuals (2.1 ± 1.2 ind.) and humpback whale group size varied between one and six individuals (2.5 ± 1.7 ind.). Fin‐ and humpback whales were observed mainly in the northern part of the study area, and were only found correlated with the presence of macro‐zooplankton in cold Arctic water. Humpback whales were not correlated with the occurrence of adult Norwegian spring‐spawning herring (Clupea harengus) except for the northernmost areas. Despite changes in the whale prey communities in the Norwegian Sea, no apparent changes in fin‐ or humpback whale distribution pattern could be found in our study compared to their observed summer distribution 10–15 years ago.  相似文献   

Fluid flow and methane occurrences in the Disko Bugt area offshore West Greenland: indications for gas hydrates?     

Tove Nielsen  Troels Laier  Antoon Kuijpers  Tine L. Rasmussen  Naja E. Mikkelsen  Niels Nørgård-Pedersen 《Geo-Marine Letters》2014,34(6):511-523

The present study is the first to directly address the issue of gas hydrates offshore West Greenland, where numerous occurrences of shallow hydrocarbons have been documented in the vicinity of Disko Bugt (Bay). Furthermore, decomposing gas hydrate has been implied to explain seabed features in this climate-sensitive area. The study is based on archive data and new (2011, 2012) shallow seismic and sediment core data. Archive seismic records crossing an elongated depression (20×35 km large, 575 m deep) on the inner shelf west of Disko Bugt (Bay) show a bottom simulating reflector (BSR) within faulted Mesozoic strata, consistent with the occurrence of gas hydrates. Moreover, the more recently acquired shallow seismic data reveal gas/fluid-related features in the overlying sediments, and geochemical data point to methane migration from a deeper-lying petroleum system. By contrast, hydrocarbon signatures within faulted Mesozoic strata below the strait known as the Vaigat can be inferred on archive seismics, but no BSR was visible. New seismic data provide evidence of various gas/fluid-releasing features in the overlying sediments. Flares were detected by the echo-sounder in July 2012, and cores contained ikaite and showed gas-releasing cracks and bubbles, all pointing to ongoing methane seepage in the strait. Observed seabed mounds also sustain gas seepages. For areas where crystalline bedrock is covered only by Pleistocene–Holocene deposits, methane was found only in the Egedesminde Dyb (Trough). There was a strong increase in methane concentration with depth, but no free gas. This is likely due to the formation of gas hydrate and the limited thickness of the sediment infill. Seabed depressions off Ilulissat Isfjord (Icefjord) previously inferred to express ongoing gas release from decomposing gas hydrate show no evidence of gas seepage, and are more likely a result of neo-tectonism.  相似文献