Waters flowing out of systems are younger than the waters stored in those same systems   总被引：1，自引：0，他引：1  

Wouter R. Berghuijs  Scott T. Allen 《水文研究》2019,33(25):3251-3254

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Catchment response to lava damming: integrating field observation,geochronology and landscape evolution modelling          下载免费PDF全文

Wouter van Gorp  Jeroen M. Schoorl  Arnaud J. A. M. Temme  Tony Reimann  Jan R. Wijbrans  Darrel Maddy  Tuncer Demir  Tom Veldkamp 《地球表面变化过程与地形》2016,41(11):1629-1644

Combining field reconstruction and landscape evolution modelling can be useful to investigate the relative role of different drivers on catchment response. The Geren Catchment (~45 km²) in western Turkey is suitable for such a study, as it has been influenced by uplift, climate change and lava damming. Four Middle Pleistocene lava flows (⁴⁰Ar/³⁹Ar‐ dated from 310 to 175 ka) filled and dammed the Gediz River at the Gediz–Geren confluence, resulting in base‐level fluctuations of the otherwise uplift‐driven incising river. Field reconstruction and luminescence dating suggest fluvial terraces in the Geren Catchment are capped by Middle Pleistocene aggradational fills. This showed that incision of the Geren trunk stream has been delayed until the end of MIS 5. Subsequently, the catchment has responded to base‐level lowering since MIS 4 by 30 m of stepped net incision. Field reconstruction left us with uncertainty on the main drivers of terrace formation. Therefore, we used landscape evolution modelling to investigate catchment response to three scenarios of base‐level change: (i) uplift with climate change (rainfall and vegetation based on arboreal pollen); (ii) uplift, climate change and short‐lived damming events; (iii) uplift, climate and long‐lived damming events. Outputs were evaluated for erosion–aggradation evolution in trunk streams at two different distances from the catchment outlet. Climate influences erosion–aggradation activity in the catchment, although internal feedbacks influence timing and magnitude. Furthermore, lava damming events partly control if and where these climate‐driven aggradations occur. Damming thus leaves a legacy on current landscape evolution. Catchment response to long‐duration damming events corresponds best with field reconstruction and dating. The combination of climate and base level explains a significant part of the landscape evolution history of the Geren Catchment. By combining model results with fieldwork, additional conclusions on landscape evolution could be drawn. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Towards Geostatistical Learning for the Geosciences: A Case Study in Improving the Spatial Awareness of Spectral Clustering     

Talebi  H.  Peeters  L. J. M.  Mueller  U.  Tolosana-Delgado  R.  van den Boogaart  K. G. 《Mathematical Geosciences》2020,52(8):1035-1048

Mathematical Geosciences - The particularities of geosystems and geoscience data must be understood before any development or implementation of statistical learning algorithms. Without such...  相似文献   

Unanswered questions on the Budyko framework     

Wouter R. Berghuijs  Sebastian J. Gnann  Ross A. Woods 《水文研究》2020,34(26):5699-5703

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Contribution of occult precipitation to the water balance of páramo ecosystems in the Colombian Andes          下载免费PDF全文

Maria Fernanda Cárdenas  Conrado Tobón  Wouter Buytaert 《水文研究》2017,31(24):4440-4449

Páramos are high‐altitudinal neotropical ecosystems located in the upper regions of the northern Andes. Their hydrology is characterized by an extraordinarily high run‐off ratio. One major contributing mechanism is thought to be fog occurrence, which is common in the páramos and occurs by the cooling of near‐surface moist air, as it is forced to higher elevations by topography. However, field‐based observations and quantification of this flux are rare. We present results of monitoring of occult precipitation, understood as the combination of fog and drizzle inputs, combined with meteorological and soil moisture monitoring for periods between 7 to 17 months in 6 sites distributed over 3 páramos catchments in Colombia: three sites in Romerales (Quindío), two in Chingaza (Cundinamarca), and one in Belmira (Antioquia). Occult precipitation inputs were measured with cylindrical fog gauges with a cover on top. We estimate occult precipitation inputs to add between 7% and 28% to rainfall inputs in the study sites. Our results also show that occult precipitation has a large temporal and spatial variability, both within one site and between sites, which make it difficult to upscale and quantify at a catchment scale. Nevertheless, occult precipitation can be important for downstream water supply given that these inputs are especially concentrated during periods with low rainfall. Lastly, we also find evidence for an increase in soil moisture related to occult precipitation during a dry period in Romerales páramo.  相似文献   

The Ituwa Surge deposits of the Holocene Ngozi caldera,Mbeya Region,Tanzania     

Nils Lenhardt  Gert-Jan Peeters  Athanas S. Macheyeki 《International Journal of Earth Sciences》2015,104(3):749-751

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Projections of future floods and hydrological droughts in Europe under a +2°C global warming   总被引：1，自引：0，他引：1  

Philippe Roudier  Jafet C. M. Andersson  Chantal Donnelly  Luc Feyen  Wouter Greuell  Fulco Ludwig 《Climatic change》2016,135(2):341-355

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Satellite Estimates of Wide-Range Suspended Sediment Concentrations in Changjiang (Yangtze) Estuary Using MERIS Data   总被引：4，自引：0，他引：4  

Fang Shen  Wouter Verhoef  Yunxuan Zhou  Mhd. Suhyb Salama  Xiaoli Liu 《Estuaries and Coasts》2010,33(6):1420-1429

The Changjiang (Yangtze) estuarine and coastal waters are characterized by suspended sediments over a wide range of concentrations from 20 to 2,500 mg l⁻¹. Suspended sediment plays important roles in the estuarine and coastal system and environment. Previous algorithms for satellite estimates of suspended sediment concentration (SSC) showed a great limitation in that only low to moderate concentrations (up to 50 mg l⁻¹) could be reliably estimated. In this study, we developed a semi-empirical radiative transfer (SERT) model with physically based empirical coefficients to estimate SSC from MERIS data over turbid waters with a much wider range of SSC. The model was based on the Kubelka–Munk two-stream approximation of radiative transfer theory and calibrated using datasets from in situ measurements and outdoor controlled tank experiments. The results show that the sensitivity and saturation level of remote-sensing reflectance to SSC are dependent on wavelengths and SSC levels. Therefore, the SERT model, coupled with a multi-conditional algorithm scheme adapted to satellite retrieval of wide-range SSC, was proposed. Results suggest that this method is more effective and accurate in the estimation of SSC over turbid waters.  相似文献   

Irradiated benzene ice provides clues to meteoritic organic chemistry     

Michael P. Callahan  Perry A. Gerakines  Mildred G. Martin  Zan Peeters  Reggie L. Hudson 《Icarus》2013

Aromatic hydrocarbons account for a significant portion of the organic matter in carbonaceous chondrite meteorites, as a component of both the low molecular weight, solvent-extractable compounds and the insoluble organic macromolecular material. Previous work has suggested that the aromatic compounds in carbonaceous chondrites may have originated in the radiation-processed icy mantles of interstellar dust grains. Here we report new studies of the organic residue made from benzene irradiated at 19 K by 0.8 MeV protons. Polyphenyls with up to four rings were unambiguously identified in the residue by gas chromatography–mass spectrometry. Atmospheric pressure photoionization Fourier transform mass spectrometry was used to determine molecular composition, and accurate mass measurements suggested the presence of polyphenyls, partially hydrogenated polyphenyls, and other complex aromatic compounds. The profile of low molecular weight compounds in the residue compared well with extracts from the Murchison and Orgueil meteorites. These results are consistent with the possibility that solid phase radiation chemistry of benzene produced some of the complex aromatics found in meteorites.  相似文献   

Differentiating the effect of episodic tectonism and eustatic sea-level fluctuations in foreland basins filled by alluvial fans and axial deltaic systems: insights from a three-dimensional stratigraphic forward model   总被引：4，自引：0，他引：4  

Quintijn Clevis  Poppe L. De Boer  Wouter Nijman 《Sedimentology》2004,51(4):809-835

Many studies of foreland basins have recognized a hierarchical organization in the stacking of sequences deposited by axial‐deltaic and alluvial fan systems. The hierarchy is often explained in terms of the competing control of eustasy and pulsed tectonic subsidence and the different frequencies at which these processes operate. Unravelling the relative contributions of tectonic and eustatic controls on the sequence stacking pattern is a fundamental question in foreland basin analysis, yet this is difficult because of the lack of independent stratigraphic evidence. In this study, a three‐dimensional numerical model is presented, which aids in the interpretation of alluvial successions in foreland basins filled by transverse and axial depositional systems, under conditions of variable tectonism and eustatic sea‐level change. The tectono‐sedimentary model is capable of simulating the hierarchical stratigraphic response to both eustatic and tectonic forcing, and is of higher resolution than previous models of foreland basin filling. Numerical results indicate that the onset of tectonic activity is reflected by rapid retrogradation of both depositional systems and by widespread flooding and onlap of carbonate sediments. Syntectonic fluvial patterns on the axial‐deltaic plain are dominated by bifurcating channels, swiftly relocating in response to the general rise in relative sea level induced by flexural subsidence. The resulting surface morphology of the axial delta is convex upwards. Syntectonic eustatic sea‐level fluctuations result in parasequence‐scale packages of retrograding and prograding fan and delta sediments bounded by minor flooding surfaces and type 2 sequence boundaries. Incised channels are rare within the syntectonic parasequences and are formed only during phases of tectonic quiescence when eustatic falls are no longer compensated by the subsidence component in the rise in relative sea level. Suites of amalgamating, axial channels corresponding to multiple eustatic falls delineate the resulting type 1 unconformities. Coarse‐grained, incised‐channel fills are found in the zone between the alluvial fan fringes and the convex‐upward body of the axial delta, as the axial streams tend to migrate towards this zone of maximum accommodation.  相似文献