A test of TOPMODEL'a ability to predict spatially distributed groundwater levels     

JAN SEIBERT  KEVIN H. BISHOP  LARS NYBERG 《水文研究》1997,11(9):1131-1144

TOPMODEL was calibrated to a small catchment using precipitation and runoff data. Acceptable fits of simulated and observed runoff were obtained during both the calibration and validation periods. Predictions of groundwater levels using this calibration did not agree well with observations at the 37 points within the catchment where groundwater levels were measured, including three locations with continuous recordings. Groundwater level observations at one single point in time, however, sufficed to calibrate new topographic–soil indices that improved the prediction of the local groundwater levels at the observed tubes. This suggests that spatially distributed calibration data are necessary to exploit reliably TOPMODEL's ability to predict spatially distributed hydrology. The mean or recalibrated transmissivity values at these 37 points differed from the catchment mean as determined by the precipitation–runoff calibration. Thus, while groundwater information can help in predicting groundwater levels at specific locations, increasing the number of local groundwater level measurements is not sufficient to improve the spatially distributed representation of subsurface flow by TOPMODEL for the catchment as a whole, as long as the groundwater information is not integrated in the precipitation–runoff calibration. © 1997 John Wiley & Sons, Ltd.  相似文献   

Carl C:zon Caldenius - geologist, geotechnician, predecessor of IGCP     

JAN LUNDQVIST 《Boreas: An International Journal of Quaternary Research》1991,20(2):183-189

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Palaeomagnetic records from two varved clay sequences in the Middle Swedish ice marginal zone     

PER SANDGREN  SVANTE BJÖRCK  LARS BRUNNBERG  JAN KRISTIANSSON 《Boreas: An International Journal of Quaternary Research》1988,17(2):215-227

Two varved clay sequences, at Rystad and Tottnäs, situated in the Middle Swedish ice marginal zone were analysed palaeomagnetically. Two parallel profiles were sampled and analysed at each site. The varved clay at Rystad was dated by floating varve chronology. The varves at Tottnäs can be linked to Swedish time scale, expressed in calendar years B.P. Due to the distance between the sites they cannot be correlated by means of varve diagrams. Palaemagnetic methods were used as an alternative. Based an AF demanetization of pilot samples, the palaeomanetic to be too low, in the order of15, compared to the site latitude. At Tottnäs the inclination records are very close to the expected inclination with respect to the site latitude. Because of a systematic inclination error in the Rystad profiles the correlation was based on the declination records. Statistical comparisons of these records between the two sites indicate that the sediment successions are partly synchronous. It is concluded that the deglaciation at Tottnäs started c. 130 years earlier than at Rystad. This mean that the Swedish ice marginal zone east of Rystad will have a more northeasterly extension than previously thought.  相似文献   

Modelling dry deposition of SO₂     

JAN WILLEM ERISMAN  DENNIS BALDOCCHI 《Tellus. Series B, Chemical and physical meteorology》1994,46(3):159-171

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The Late Weichselian glacial maximum in western Svalbard     

JAN MANGERUD  MAGNE BOLSTAD  ANNE ELGERSMA  DAG HELLIKSEN  JON Y. LANDVIK  ANNE KATRINE LYCKE  IDA LØNNE  OTTO SALVIGSEN  TOM SANDAHL  HANS PETTER SEJRUP 《Polar research》1987,5(3):275-278

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Modelling land atmosphere exchange of gaseous oxides of nitrogen in Europe     

JAN DUYZER  DAVID FOWLER 《Tellus. Series B, Chemical and physical meteorology》1994,46(5):353-372

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Deep‐seated relict permafrost in northeastern Poland     

JAN SZEWCZYK  JERZY NAWROCKI 《Boreas: An International Journal of Quaternary Research》2011,40(3):385-388

Szewczyk, J. & Nawrocki, J. 2011: Deep‐seated relict permafrost in northeastern Poland. Boreas, Vol. 40, pp. 385–388. 10.1111/j.1502‐3885.2011.00218.x. ISSN 0300‐9483. A research borehole drilled in northeastern Poland revealed a permafrost layer at least 93 m thick within the Cretaceous sedimentary succession below a depth of 357 m. Its entire thickness has not been determined, owing to the borehole depth limit (450 m). The relict of permafrost, unexpected in this part of Europe, is in the ice–water transition phase at a temperature close to 0 °C. We estimate that the permafrost has been preserved in an area of several square kilometres located above the central part of the Suwa?ki anorthosite intrusion, which is covered by ～800 m of sedimentary rocks. We show that the remnants of the Last Glaciation, which ended at c. 13.4 ka BP, can, even at present, affect the thermal regime of the outer zone of the Earth's crust. These findings are of significant importance for the reconstruction of past climate conditions.  相似文献   

A multi‐dating approach applied to proglacial sediments attributed to the Most Extensive Glaciation of the Swiss Alps     

ANDREAS DEHNERT  FRANK PREUSSER  JAN D. KRAMERS  NAKI AKÇAR  PETER W. KUBIK  REGINA REBER  CHRISTIAN SCHLÜCHTER 《Boreas: An International Journal of Quaternary Research》2010,39(3):620-632

Dehnert, A., Preusser, F., Kramers, J. D., Akçar, N., Kubik, P. W., Reber, R. & Schlüchter, C. 2010: A multi‐dating approach applied to proglacial sediments attributed to the Most Extensive Glaciation of the Swiss Alps. Boreas, Vol. 39, pp. 620–632. 10.1111/j.1502‐3885.2010.00146.x. ISSN 0300‐9483. The number and the timing of Quaternary glaciations of the Alps are poorly constrained and, in particular, the age of the Most Extensive Glaciation (MEG) in Switzerland remains controversial. This ice advance has previously been tentatively correlated with the Riss Glaciation of the classical alpine stratigraphy and with Marine Isotope Stage (MIS) 6 (186–127 ka). An alternative interpretation, based on pollen analysis and stratigraphic correlations, places the MEG further back in the Quaternary, with an age equivalent to MIS 12 (474–427 ka), or even older. To re‐evaluate this issue in the Swiss glaciation history, a multi‐dating approach was applied to proglacial deltaic ‘Höhenschotter’ deposits in locations outside the ice extent of the Last Glacial Maximum. Results of U/Th and luminescence dating suggest a correlation of the investigated deposits with MIS 6 and hence with the Riss Glaciation. Cosmogenic burial dating suffered from large measurement uncertainties and unusually high ²⁶Al/¹⁰Be ratios and did not provide robust age estimates.  相似文献   

Climate stability during the Eemian – new pollen evidence from the Nidzica site,northern Poland     

KRZYSZTOF BIŃKA  JERZY NITYCHORUK  JAN DZIERŻEK 《Boreas: An International Journal of Quaternary Research》2011,40(2):342-350

Bińka, K., Nitychoruk, J. & Dzier?ek, J. 2010: Climate stability during the Eemian – new pollen evidence from the Nidzica site, northern Poland. Boreas, 10.1111/j.1502‐3885.2010.00179.x. ISSN 0300‐9483 Interglacial sediments at Nidzica, northern Poland were investigated by means of pollen and isotope analysis. These deposits accumulated in an extensive basin through most of the Eemian and Early Weichselian, practically without stratigraphic gaps. Continuous subsidence of the basin floor has resulted in the accumulation of a great thickness of lacustrine sediments, consisting mostly of calcareous gyttja. The course of pollen and isotope curves in the interglacial interval does not indicate the abrupt climatic shifts reported from some other continental climatic archives. Particularly important has been the reconstruction of the final stages of the Eemian, a potential analogue for future climatic change in the late Holocene. At Nidzica, this period is registered as a gradual modification of forest composition, devoid of any pulsations in which temperate forest is followed by terminal, boreal pine–birch communities.  相似文献   

Aeolian construction and alluvial dismantling of a fault‐bounded intracontinental aeolian dune field (Teruel Basin,Spain); a continental perspective on Late Pliocene climate change and variability     

JUAN PEDRO RODRÍGUEZ‐LÓPEZ  CARLOS L. LIESA  JAN VAN DAM  PALOMA LAFUENTE  LUIS ARLEGUI  LOPE EZQUERRO  POPPE L. DE BOER 《Sedimentology》2012,59(5):1536-1567

An aeolian dune field migrating to the east encroached on the toes of alluvial fans in the Teruel Basin (eastern Spain) during a short interval in the Late Pliocene (ca 2·9 to 2·6 Ma), when Northern Hemisphere glaciation and strong glacial–interglacial cycles began. Preservation of the dune field was controlled by syn‐sedimentary activity of a normal fault. Ephemeral water discharge eroded aeolian sands and formed V‐shaped channels in which aeolian sandstone blocks accumulated. The incorporation of loose aeolian sand in wadi waters modified the sediment/water ratio, changing the physical properties of the flows as they penetrated the aeolian dune field. The erosion and cover of aeolian dune foresets by sheetflood deposits suggest that dune‐damming caused the intermittent ponding of water behind the dunes and its flashy release. The arid climate in the Late Pliocene western Mediterranean realm favoured the transport of windblown sediments from northern Africa and western Mediterranean land masses into the Mediterranean. The formation of the studied aeolian dune field (2·9 to 2·6 Ma) and possibly others (for example, the Atacama, Namib and Sahara deserts) correlates with a strong increase of the influence of obliquity, which can be attributed to the combination of a regional expression related to the reduced effect of precession due to a minimum in the long‐period (2·3 Ma) eccentricity cycle and a remote expression of the onset of the Northern Hemisphere glaciation.  相似文献