Modeling the role of rainfall patterns in seasonal malaria transmission     

Arne Bomblies 《Climatic change》2012,112(3-4):673-685

Seasonal total precipitation is well known to affect malaria transmission because Anopheles mosquitoes depend on standing water for breeding habitat. However, the within-season temporal pattern of the rainfall influences persistence of standing water and thus rainfall patterns can also affect mosquito population dynamics in water-limited environments. Here, using a numerical simulation, I show that intraseasonal rainfall pattern accounts for 39% of the variance in simulated mosquito abundance in a Niger Sahel village where malaria is endemic but highly seasonal. I apply a field validated coupled hydrology and entomology model. Using synthetic rainfall time series generated using a stationary first-order Markov Chain model, I hold all variables except hourly rainfall constant, thus isolating the contribution of rainfall pattern to variance in mosquito abundance. I further show the utility of hydrology modeling using topography to assess precipitation effects by analyzing collected water. Time-integrated surface area of pools explains 70% of the variance in simulated mosquito abundance from a mechanistic model, and time-integrated surface area of pools persisting longer than 7?days explains 82% of the variance. Correlations using the hydrology model output explain more variance in mosquito abundance than the 60% from rainfall totals. I extend this analysis to investigate the impacts of this effect on malaria vector mosquito populations under climate shift scenarios, holding all climate variables except precipitation constant. In these scenarios, rainfall mean and variance change with climatic change, and the modeling approach evaluates the impact of non-stationarity in rainfall and the associated rainfall patterns on expected mosquito activity.  相似文献   

Determining return water levels at ungauged coastal sites: a case study for northern Germany   总被引：1，自引：0，他引：1  

Arne Arns  Thomas Wahl  Ivan D. Haigh  Jürgen Jensen 《Ocean Dynamics》2015,65(4):539-554

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Architecture of tunnel valleys in the southeastern North Sea: new insights from high-resolution seismic imaging     

Arne Lohrberg  Klaus Schwarzer  Daniel Unverricht  Andreas Omlin  Sebastian Krastel 《第四纪科学杂志》2020,35(7):892-906

Tunnel valleys are assumed to form near the margin of ice sheets. Hence, they can be used to reconstruct the dynamics of former ice margins. The detailed formation and infill of tunnel valleys, however, are still not well understood. Here, we present a dense grid of high-resolution 2D multi-channel reflection seismic data from the German sector of the southeastern North Sea imaging tunnel valleys in very great detail. Three tunnel valley systems were traced over distances ranging between 11 and 21 km. All tunnel valleys are completely filled and buried. They differ in incision depth, incision width and number of incisions. The tunnel valleys cut 130–380 m deep into Neogene, Palaeogene and Cretaceous sediments; they show a lower V-shaped and an upper U-shaped morphology. For individual tunnel valleys, the overall incision direction ranges from east–west to northeast–southwest. Two tunnel valleys intersect at an oblique angle without reuse of the thalweg. These valleys incise into a pre-existing glaciotectonic complex consisting of thrust sheets in the northwest of the study area. The analysis of the glaciotectonic complex and the tunnel valleys leads us to assume that we identified several marginal positions of (pre-)Elsterian ice lobes in the southeastern North Sea.  相似文献   

The Origin of the Proterozoic Bidjovagge Gold-Copper Deposit, Finnmark, Northern Norway, as Deduced from Rare Earth Element and Nd Isotopic Evidences on Calcites     

Feng–Jun NIE  Arne BJ&#;RLYKKE  Kjell S. NILSEN 《Resource Geology》1999,49(1):13-25

Abstract: The Bidjovagge gold-copper deposit, northern Norway occurs in the lower Proterozoic Kautokeino greenstone belt, and consists of ten ore bodies in albite felsite, graphite schist and meta-diabase sills, along with a series of syenodiorite dykes. Calcite is one of the most important gangue minerals occurring within the ore veins. The early primary calcite samples from A, C and D ore bodies (copper–rich) show almost flat chondrite-normalised REE curves, and slightly positive Eu anomalies. A Sm-Nd isotope age of 1858 ± 72 Ma (2ρ) has been given based on fifteen primary calcite samples. The Sm-Nd age of calcite is in well agreement with previously published U-Pb davidite age of 1885 ±18 Ma (2ρ) and Sm-Nd davidite age of 1886 ± 88 Ma (2ρ). All these isotopic age data indicate that the gold-copper mineralisation may occur during or slightly after the peak of the Svecokarelian orogeny. Two late primary calcite samples from C and D ore bodies have flat chondrite-normalised LREE curves, positive HREE curves, and negative Eu anomalies. In contrast, most of the early primary calcite samples from B ore body (gold–rich) show an overall negative chondrite-normalised REE slope and negative Eu anomalies. Sm-Nd data on seven primary calcite samples from the B ore body are relatively scattered, and gave an isochrone age of 1809 ± 150 Ma (2ρ), identical to the age of the calcite samples from A, C and D ore bodies. Two late primary calcite samples from the B ore body have almost flat chondrite-normalised REE slope and negative Eu anomalies. REE patterns and eNd (T) values of calcites suggest that the ore fluids for the calcites from the A, C and D ore bodies derived their metals from mafic igneous rocks (diabase sills). For the secondary calcites from the C ore body, their relative high initial Nd (T) values at 1858 Ma imply that much more radiogenic Nd-component were incorporated during calcite crystallisation when another ore fluid emplaced. Combined Nd isotope data and REE geochemical features suggest that the isotopically more evolved source such as albite felsite and syn-genetic high level syenodiorite dykes were probably metal source for these calcites in the B ore body. Three samples of secondary calcite from the B ore body, which obviously deviated from 1809 Ma isochron are easily explained as products of post-ore hydrothermal events.  相似文献   

Effect of warming and nitrogen addition on evapotranspiration and water use efficiency in a wheat-soybean/fallow rotation from 2010 to 2014   总被引：1，自引：0，他引：1  

Liting Liu  Chunsheng Hu  Jørgen E. Olesen  Zhaoqiang Ju  Xiying Zhang 《Climatic change》2016,139(3-4):565-578

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Timing of gold mineralisation in the Ballarat goldfields,central Victoria: Constraints from 40Ar/39Ar results     

F. P. Bierlein  D. A. Foster  S. McKnight  D. C. Arne 《Australian Journal of Earth Sciences》2013,60(2):301-309

⁴⁰Ar/³⁹Ar data for muscovite separates and hydrothermally altered whole‐rock samples from the Ballarat West and the Ballarat East goldfields indicate that mesothermal gold mineralisation at Ballarat occurred during several episodic pulses, ranging in age from the Late Ordovician to the Early Devonian. Initial formation of auriferous structures in the Ballarat goldfields coincided with folding and thrusting associated with the development of the western Lachlan Fold Belt between 460 and 440 Ma. Subsequent fault reactivation and magmatism resulted in remobilisation and additional mineralisation between 410 and 380 Ma, and around 370 Ma. The results presented herein are in agreement with findings for other major gold deposits in central Victoria and further constrain the history of deformation, metamorphism and mineralisation in the western subprovince of the Lachlan Fold Belt.  相似文献   

Detection of land subsidence in Semarang,Indonesia, using stable points network (SPN) technique   总被引：2，自引：0，他引：2  

Friedrich Kuehn  David Albiol  Geraint Cooksley  Javier Duro  Johanna Granda  Susanne Haas  Arne Hoffmann-Rothe  Dodid Murdohardono 《Environmental Earth Sciences》2010,60(5):909-921

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Geological observations in high‐grade mid‐Proterozoic rocks from Else Platform,northern Prince Charles mountains region,east Antarctica     

M. Hand  C. J. L. Wilson  I. Scrimgeour  Kurt Stüwe  D. Arne 《Australian Journal of Earth Sciences》2013,60(4):311-329

Granulite facies rocks on Else Platform in the northern Prince Charles Mountains, east Antarctica, consist of metasedimentary gneiss extensively intruded by granitic rocks. The dominant rock type is a layered garnetbiotite‐bearing gneiss intercalated with minor garnet‐cordierite‐sillimanite gneiss and calc‐silicate. Voluminous megacrystic granite intruded early during a mid‐Proterozoic (ca 1000 Ma) granulite event, M₁, widely recognized in east Antarctica. Peak metamorphic conditions for M₁ are in the range of 650–750 MPa at ～800°C and were associated with the development of a gneissic foliation, S₁ and steep east‐plunging lineation, L₁. Strain partitioning during progressive non‐coaxial deformation formed large D₂ granulite facies south‐dipping thrusts, with a steep, east‐plunging lineation. In areas of lower D₂ strain, large‐scale upright, steep east‐plunging fold structures formed synchronously with the D₂ high‐strain zones. Voluminous garnet‐bearing leucogneiss intruded at 940 ±20 Ma and was deformed in the D₂ high‐strain zones. Textural relationships in pelitic rocks show that peak‐M2 assemblages formed during increasing temperatures via reactions such as biotite + sillimanite + quartz ± plagioclase = spinel + cordierite + ilmenite + K‐feldspar + melt. In biotite‐absent rocks, re‐equilibration of deformed M₁ garnet‐sillimanite‐ilmenite assemblages occurred through decompressive reactions of the form, garnet + sillimanite + ilmenite = cordierite + spinel + quartz. Pressure/temperature estimates indicate that peak‐M₂ conditions were 500–600 MPa and 700±50°C. At about 500 Ma, north‐trending granitic dykes intruded and were deformed during D₃‐M₃ at probable upper amphibolite facies conditions. Cooling from peak D₃‐M₃ conditions was associated with the formation of narrow greenschist facies shear zones, and the intrusion of pegmatite. Cross‐cutting all features are abundant north‐south trending alkaline mafic dykes that were emplaced over the interval ca 310–145 Ma, reflecting prolonged intrusive activity. Some of the dykes are associated with steeply dipping faults that may be related to basin formation during Permian times and later extension, synchronous with the formation of the Lambert Graben in the Cretaceous.  相似文献   

Asynchronous responses of East Asian and Indian summer monsoons to mountain uplift shown by regional climate modelling experiments   总被引：1，自引：1，他引：0  

Hui Tang  Arne Micheels  Jussi T. Eronen  Bodo Ahrens  Mikael Fortelius 《Climate Dynamics》2013,40(5-6):1531-1549

It has been demonstrated in climate models that both the Indian and East Asian summer monsoons (ISM and EASM) are strengthened by the uplift of the entire Asian orography or Tibetan Plateau (TP) (i.e. bulk mountain uplift). Such an effect is widely perceived as the major mechanism contributing to the evolution of Asian summer monsoons in the Neogene. However, geological evidence suggests more diachronous growth of the Asian orography (i.e. regional mountain uplift) than bulk mountain uplift. This demands a re-evaluation of the relation between mountain uplift and the Asian monsoon in the geological periods. In this study, sensitivity experiments considering the diachronous growth of different parts of the Asian orography are performed using the regional climate model COSMO-CLM to investigate their effects on the Asian summer monsoons. The results show that, different from the bulk mountain uplift, the regional mountain uplift can lead to an asynchronous development of the ISM and EASM. While the ISM is primarily intensified by the thermal insulation (mechanical blocking) effect of the southern TP (Zagros Mountains), the EASM is mainly enhanced by the surface sensible heating of the central, northern and eastern TP. Such elevated surface heating can induce a low-level cyclonic anomaly around the TP that reduces the ISM by suppressing the lower tropospheric monsoon vorticity, but promotes the EASM by strengthening the warm advection from the south of the TP that sustains the monsoon convection. Our findings provide new insights to the evolution of the Asian summer monsoons and their interaction with the tectonic changes in the Neogene.  相似文献   

Innovation by co-evolution in natural resource industries: The Norwegian experience     

Bjørnar Sæther  Arne Isaksen 《Geoforum》2011,42(3):373-381

Some resource-based economies become wealthy while others stay poor and Norway belongs to the first category. This paper argues that part of the answer to why Norway has managed to benefit from its rich natural resources is found in the formation of a well-functioning national innovation system. The paper integrates the innovation system approach with a historical approach through the concept of co-evolution. The empirical study investigates how innovation systems evolve in natural resource industries through analysing the co-evolution between industry, knowledge organisations and national policy in the Norwegian aluminium and petroleum sectors. Parallels are found in the development of these two sectors, which are: (i) the deliberate use of concession laws to seize value creation and technological development from foreign direct investments, (ii) the establishment and prioritisation of state-owned companies and (iii) the more or less intentional formation of a national innovation system. The paper points to the relevance of analysing the historical evolution of national innovation systems to understand the creation of their specific path-dependent characteristics, to analyse how policy influences the creation and working of innovation systems, to use a multilevel approach in studies of innovation systems and to consider how innovation processes in different industries are linked in value chains and through knowledge flows.  相似文献