Bright spectroscopic binaries: III. Binary systems with orbital periods of P > 500 days     

Dennis Jack  Missael Alejandro Hernández Huerta  Faiber Danilo Rosas-Portilla  Klaus-Peter Schröder 《Astronomische Nachrichten》2024,345(1):e230123

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Soil-precipitation feedbacks during the South American Monsoon as simulated by a regional climate model   总被引：1，自引：0，他引：1  

Anna A. Sörensson  Claudio G. Menéndez  Patrick Samuelsson  Ulrika Willén  Ulf Hansson 《Climatic change》2010,98(3-4):429-447

We summarize the recent progress in regional climate modeling in South America with the Rossby Centre regional atmospheric climate model (RCA3-E), with emphasis on soil moisture processes. A series of climatological integrations using a continental scale domain nested in reanalysis data were carried out for the initial and mature stages of the South American Monsoon System (SAMS) of 1993–92 and were analyzed on seasonal and monthly timescales. The role of including a spatially varying soil depth, which extends to 8 m in tropical forest, was evaluated against the standard constant soil depth of the model of about 2 m, through two five member ensemble simulations. The influence of the soil depth was relatively weak, with both beneficial and detrimental effects on the simulation of the seasonal mean rainfall. Secondly, two ensembles that differ in their initial state of soil moisture were prepared to study the influence of anomalously dry and wet soil moisture initial conditions on the intraseasonal development of the SAMS. In these simulations the austral winter soil moisture initial condition has a strong influence on wet season rainfall over feed back upon the monsoon, not only over the Amazon region but in subtropical South America as well. Finally, we calculated the soil moisture–precipitation coupling strength through comparing a ten member ensemble forced by the same space–time series of soil moisture fields with an ensemble with interactive soil moisture. Coupling strength is defined as the degree to which the prescribed boundary conditions affect some atmospheric quantity in a climate model, in this context a quantification of the fraction of atmospheric variability that can be ascribed to soil moisture anomalies. La Plata Basin appears as a region where the precipitation is partly controlled by soil moisture, especially in November and January. The continental convective monsoon regions and subtropical South America appears as a region with relatively high coupling strength during the mature phase of monsoon development.  相似文献   

European temperature records of the past five centuries based on documentary/instrumental information compared to climate simulations     

Eduardo Zorita  Anders Moberg  Lotta Leijonhufvud  Rob Wilson  Rudolf Brázdil  Petr Dobrovolný  Jürg Luterbacher  Reinhard Böhm  Christian Pfister  Dirk Riemann  Rüdiger Glaser  Johan Söderberg  Fidel González-Rouco 《Climatic change》2010,101(1-2):143-168

Two European temperature reconstructions for the past half-millennium, January-to-April air temperature for Stockholm (Sweden) and seasonal temperature for a Central European region, both derived from the analysis of documentary sources and long instrumental records, are compared with the output of climate simulations with the model ECHO-G. The analysis is complemented by comparisons with the long (early)-instrumental record of Central England Temperature (CET). Both approaches to study past climates (simulations and reconstructions) are burdened with uncertainties. The main objective of this comparative analysis is to identify robust features and weaknesses in each method which may help to improve models and reconstruction methods. The results indicate a general agreement between simulations obtained with temporally changing external forcings and the reconstructed Stockholm and CET records for the multi-centennial temperature trend over the recent centuries, which is not reproduced in a control simulation. This trend is likely due to the long-term change in external forcing. Additionally, the Stockholm reconstruction and the CET record also show a clear multi-decadal warm episode peaking around AD 1730, which is absent in the simulations. Neither the reconstruction uncertainties nor the model internal climate variability can easily explain this difference. Regarding the interannual variability, the Stockholm series displays, in some periods, higher amplitudes than the simulations but these differences are within the statistical uncertainty and further decrease if output from a regional model driven by the global model is used. The long-term trend of the CET series agrees less well with the simulations. The reconstructed temperature displays, for all seasons, a smaller difference between the present climate and past centuries than is seen in the simulations. Possible reasons for these differences may be related to a limitation of the traditional ‘indexing’ technique for converting documentary evidence to temperature values to capture long-term climate changes, because the documents often reflect temperatures relative to the contemporary authors’ own perception of what constituted ‘normal’ conditions. By contrast, the amplitude of the simulated and reconstructed inter-annual variability agrees rather well.  相似文献   

Meeresgeologische Forschungsstelle der Universität Kiel     

Kölbl 《International Journal of Earth Sciences》1936,27(4):390-390

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Process identification through rejection of model structures in a mid‐mountainous rural catchment: observations of rainfall–runoff response,geophysical conditions and model inter‐comparison     

Thomas Graeff  Erwin Zehe  Dominik Reusser  Erika Lück  Boris Schröder  Gerald Wenk  Hermann John  Axel Bronstert 《水文研究》2009,23(5):702-718

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Mining lakes as groundwater‐dominated hydrological systems: assessment of the water balance of Mining Lake Plessa 117 (Lusatia,Germany) using stable isotopes     

Hilmar Hofmann  Kay Knöller  Dieter Lessmann 《水文研究》2008,22(23):4620-4627

In the present study, the stable isotopes δ¹⁸O and δ²H were used for assessment of the water balance in a heterogeneously structured catchment area in the Lusatian Lignite Mining District, in particular, for estimation of the annual groundwater inflow and outflow (I_GW and O_GW) of Mining Lake Plessa 117. The application of stable isotopes was possible since the water exchange in the catchment area had reached steady‐state conditions after the abandonment of mining activities in 1968 and the filling of the voids and aquifers by re‐rising groundwater in the years thereafter. Diverging slopes of the Evaporation Line and the Global Meteoric Water Line manifested as evaporation from the lake catchment area. The calculated isotope water balance was compared with the commonly used surface water balance, which is unable to differentiate between I_GW and O_GW, and with a local groundwater model. The groundwater model calculated an I_GW of about 811 000 m³ yr^?1 and an O_GW close to zero, whereas the isotope water balance showed fluxes of about 914 000 and 140 000 m³ yr^?1, respectively. Considering the contribution of the groundwater inflow to the total annual input into the lake (ΔI_T) and the mean residence time (τ), where the groundwater model and the isotope water balance calculated 42 and 47% for ΔI_T and 4·3 and 3·9 years for τ, respectively, it was shown that both water balance calculation methods led to comparable results despite the differences in I_GW and O_GW. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Chronology of the Last Glacial Maximum in the Salzach palaeoglacier area (Eastern Alps)     

Reinhard Starnberger  Helena Rodnight  Christoph Spötl 《第四纪科学杂志》2011,26(5):502-510

A chronostratigraphy based on luminescence data was established at a key loess profile (Duttendorf) in the northern alpine foreland of Austria. The data help to constrain the timing and duration of the Last Glacial Maximum (LGM) in the area of one of the largest east Alpine piedmont glaciers, the Salzach palaeoglacier. Climate deterioration and maximum advance of this glacier were coeval with the beginning of the main loess accumulation phase in the glacier forefield at ～29–30 ka. A late LGM‐outwash gravel layer deposited on top of the loess profile marks the end of the LGM glacier activity at ～20 ka. The geomorphological setting around the loess profile provides evidence of a major glacier oscillation during the course of the LGM, a phenomenon qualitatively known from other alpine palaeoglaciers but never interpreted in terms of palaeoclimate. A LGM glacier oscillation similar to that of the Salzach palaeoglacier was reported recently from the south Alpine Tagliamento palaeoglacier, suggesting a common forcing. The onset of loess deposition at Duttendorf and the tentatively contemporal advance of the Salzach palaeoglacier reflect, as do other data, the drastic cooling in Europe as a result of Heinrich event 3. The first glacier maximum is not well constrained in the study area but a correlation with the better dated Tagliamento amphitheatre suggests a possible response to Heinrich 2. The second re‐advance occurred synchronously (within dating uncertainties) in both palaeoglaciers forefields (at ～21 ka) but the forcing mechanism remains unknown. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

The western end of the Eoalpine High‐Pressure Belt (Texel unit,South Tyrol / Italy)          下载免费PDF全文

Hannah Pomella  David Flöss  Romed Speckbacher  Peter Tropper  Bernhard Fügenschuh 《地学学报》2016,28(1):60-69

Eclogites in the Texel Unit (Eastern Alps; South Tyrol, Italy) represent the westernmost outcrops of the E–W striking Eoalpine High‐Pressure Belt (EHB). East of the Tauern Window, the EHB forms part of a Cretaceous intracontinental south‐dipping subduction/collision zone; however, the same nappe stack displays a northwest dip at its western end. This prominent change in dip direction gave rise to discussions on the general setting of the Eoalpine collision. Based on our own observations and literature data, we present a new tectonic model for the western end of the EHB. Due to the special situation of this area at the tip of the Southalpine indenter, originally south(east) dipping structures became overturned, and former thrusts appear as normal faults (e.g. Schneeberg fault zone) while former normal faults presently display thrust geometries (e.g. Jaufen fault). Thus, we explain the current configuration with a coherent Eoalpine subduction direction.  相似文献   

Climate change impacts—throwing the dice?     

Günter Blöschl  Alberto Montanari 《水文研究》2010,24(3):374-381

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Book reviews     

A. Maucher  R. Höll 《Mineralium Deposita》1978,13(2):288-290

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