Suitability of North American Regional Reanalysis (NARR) output for hydrologic modelling and analysis in mountainous terrain          下载免费PDF全文

Joel W. Trubilowicz  J. M. Shea  G. Jost  R. D. Moore 《水文研究》2016,30(13):2332-2347

Meteorological observations at high elevations in mountainous regions are often lacking. One opportunity to fill this data gap is through the use of downscaled output from weather reanalysis models. In this study, we tested the accuracy of downscaled output from the North American Regional Reanalysis (NARR) against high‐elevation surface observations at four ridgetop locations in the southern Coast Mountains of British Columbia, Canada. NARR model output was downscaled to the surface observation locations through three‐dimensional interpolation for air temperature, vapour pressure and wind speed and two‐dimensional interpolation for radiation variables. Accuracy was tested at both the 3‐hourly and daily time scales. Air temperature displayed a high level of agreement, especially at the daily scale, with root mean square error (RMSE) values ranging from 0.98 to 1.21 °C across all sites. Vapour pressure downscaling accuracy was also quite high (RMSE of 0.06 to 0.11 hPa) but displayed some site specific bias. Although NARR overestimated wind speed, there were moderate to strong linear relations (r² from 0.38 to 0.84 for daily means), suggesting that the NARR output could be used as an index and bias‐corrected. NARR output reproduced the seasonal cycle for incoming short‐wave radiation, with Nash–Sutcliffe model efficiencies ranging from 0.78 to 0.87, but accuracy suffered on days with cloud cover, resulting in a positive bias and RMSE ranged from 42 to 46 Wm^{? 2}. Although fewer data were available, incoming long‐wave radiation from NARR had an RMSE of 19 Wm^{? 2} and outperformed common methods for estimating incoming long‐wave radiation. NARR air temperature showed potential to assist in hydrologic analysis and modelling during an atmospheric river storm event, which are characterized by warm and wet air masses with atypical vertical temperature gradients. The incorporation of a synthetic NARR air temperature station to better represent the higher freezing levels resulted in increased predicted peak flows, which better match the observed run‐off during the event. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Fluid elemental and stable isotope composition of the Nibelungen hydrothermal field (8°18′S,Mid-Atlantic Ridge): Constraints on fluid–rock interaction in heterogeneous lithosphere     

K. Schmidt  D. Garbe-Schönberg  A. Koschinsky  H. Strauss  C.L. Jost  V. Klevenz  P. Königer 《Chemical Geology》2011,280(1-2):1-18

Depending on the geological setting, the interaction of submarine hydrothermal fluids with the host rock leads to distinct energy and mass transfers between the lithosphere and the hydrosphere. The Nibelungen hydrothermal field is located at 8°18′S, about 9 km off-axis of the Mid-Atlantic Ridge (MAR). At 3000 m water depth, 372 °C hot, acidic fluids emanate directly from the bottom, without visible sulfide chimney formation. Hydrothermal fluids obtained in 2009 are characterized by low H₂S concentrations (1.1 mM), a depletion of B (192 μM) relative to seawater, lower Si (13.7 mM) and Li (391 μM) concentrations relative to basaltic-hosted hydrothermal systems and a large positive Eu anomaly, and display a distinct stable isotope signature of hydrogen (?²H_H2O = 7.6–8.7‰) and of oxygen (?¹⁸O_H2O = 2.2–2.4‰).The heavy hydrogen isotopic signature of the Nibelungen fluids is a specific feature of ultramafic-hosted hydrothermal systems and is mainly controlled by the formation of OH-bearing alteration minerals like serpentine, brucite, and tremolite during pervasive serpentinization. New isotopic data obtained for the ultramafic-hosted Logatchev I field at 14°45′N, MAR (?²H_H2O = 3.8–4.2‰) display a similar trend, being clearly distinguished from other, mafic-hosted hydrothermal systems at the MAR.The fluid geochemistry at Nibelungen kept stable since the first sampling campaign in 2006 and is evident for a hybrid alteration of mafic and ultramafic rocks in the subseafloor. Whereas the ultramafic-fingerprint parameters Si, Li, B, Eu anomaly and ?²H_H2O distinguish the Nibelungen field from other hydrothermal systems venting in basaltic settings at similar physico-chemical conditions and are related to the interaction with mantle rocks, the relatively high concentrations of trace alkali elements, Pb, and Tl can only be attributed to the alteration of melt-derived gabbroic rocks. The elemental and isotopic composition of the fluid suggest a multi-step alteration sequence: (1) low- to medium-temperature alteration of gabbroic rocks, (2) pervasive serpentinization at moderate to high temperatures, and (3) limited high-temperature interaction with basaltic rocks during final ascent of the fluid. The integrated water/rock ratio for the Nibelungen hydrothermal system is about 0.5.The fluid compositional fingerprint at Nibelungen is similar to the ultramafic-hosted Logatchev I fluids with respect to key parameters. Some compositional differences can be ascribed to different alteration temperatures and other fluid pathways involving a variety of source rocks, higher water/rock ratios, and sulfide precipitation in the sub-seafloor at Logatchev I.  相似文献   

Henry's law and hydrolysis-rate constants for peroxyacyl nitrates (PANs) using a homogeneous gas-phase source     

Jost Kames  Ulrich Schurath 《Journal of Atmospheric Chemistry》1995,21(2):151-164

The solubilities and hydrolysis rates of PAN (peroxyacetyl nitrate) and its homologues PPN (peroxypropionyl nitrate), PnBN (peroxy-n-butyl nitrate), PiBN (peroxy-isobutyl nitrate) and MPAN (peroxymethacryloyl nitrate) in liquid water have been studied at 20 °C. Temperature dependencies were measured for PAN and PPN. The solubilities of peroxyacyl nitrates decrease smoothly with increasing carbon-chain length fromH (293 K)=4.1 M atm^–1 (PAN) toH (293 K)=1.0 M atm^–1 (PiBN). Hydrolysis-rate constants, which cover the range fromk _h (293 K)=(2.4–7.4)×10^–4 s^–1, do not show a systematic chain-length dependency. Solubilities of PAN and PPN in solutions which mimic the composition and ionic strength of sea water are 15% and 20% lower than in pure water. The hydrolysis rate constants are not affected.  相似文献   

Post-drought increase in regional-scale groundwater nitrate in southwest Germany     

Karuna Jutglar  Jost Hellwig  Michael Stoelzle  Jens Lange 《水文研究》2021,35(8):e14307

Elevated nitrate concentrations in groundwater are a common challenge for water management. One important factor in this context is higher frequencies and intensities of wet-dry cycles that may cause increased nitrate concentrations in groundwater due to nitrate flushes after drought termination. Yet systematic studies on regional-scale impacts of droughts on groundwater nitrate concentrations are missing so far. Here we analyzed time series of 44 shallow groundwater wells and 41 springs all across the German Federal State Baden-Wuerttemberg from 2000 to 2018 to characterize patterns of post-drought nitrate increase in groundwater. In general, half of the exceptional nitrate concentrations, which exceeded the 80th percentile of long-term nitrate measurements, could be related to droughts in the research timeframe. The 2003 drought event stood out in terms of drought severity and post-drought nitrate concentration increases in our data. The great majority (91%) of all monitoring sites showed at least one exceptionally high nitrate concentration in the 4 years following the 2003 drought event. Springs were mainly located in forests of steep low mountain ranges and wells in cropland of flat river valleys. Therefore, delay times between drought intensity and nitrate concentration increases as well as magnitudes of nitrate concentration increase were diverse among wells and springs. We derived two distinct nitrate response patterns: (i) nitrate increases immediately following drought events (more common for springs and fractured rock aquifers) and (ii) delayed nitrate increases (more common for wells and porous aquifers). Springs generally showed quicker (median of 101 days) but weaker (median of +1.3 mg/L) post-drought nitrate increases than wells (185 days, +3.4 mg/L). Only few sites exhibited no post-drought nitrate increase and post-drought mean-nitrate concentrations of groundwater reservoirs were extraordinarily high in 2006. Overall, we demonstrate that post-drought nitrate increase in groundwater is omnipresent, while different landscapes and hydrogeological characteristics create a diverse regional pattern. As severe droughts become more frequent in a changing climate, post-drought nitrate increase may intensify problems regarding water quality and supply.  相似文献   

Partitioning Stakeholders for the Economic Valuation of Ecosystem Services: Examples of a Mangrove System     

Tatiane Micheletti  François Jost  Uta Berger 《Natural Resources Research》2016,25(3):331-345

Although the importance of ecosystem services provided by natural forests, especially mangroves, is well known, the destruction of these environments is still ubiquitous and therefore protection measures are urgently needed. The present study compares the current approach of economic valuation of ecosystem services to a proposed one, using a study case of a mangrove system as an example. We suggest that a cost-benefit analysis for economically valuing environmental services should be performed with three additional modifications consisting of (i) a categorization of local stakeholders as demanders of particular ecosystem services, (ii) acknowledgement of the government as one of these demander groups, and (iii) the inclusion of opportunity costs in the valuation. The application of this approach to the mangrove area in the east portion of Great Abaco Island, the Bahamas, reveals that not only the ecosystem services received differ between demander groups, but the monetary benefits and costs are also specific to each of these groups. We show that the economic valuation of the ecosystem should be differentiated for each category, instead of being calculated as a net ‘societal value’ as it is currently. Applying this categorization of demanders enables a better understanding of the cost and benefit structure of the protection of a natural area. The present paper aims to facilitate discussions regarding benefit and cost sharing related to the protection of natural areas.  相似文献   

Fault plane solutions of microearthquakes and small events in the Hellenic arc     

Michael L. Jost  Olaf Knabenbauer  Jin Cheng  Hans-Peter Harjes   《Tectonophysics》2002,356(1-3)

The Hellenic arc is the most active seismic region of the transition zone between the African and Eurasian plates. In this rapidly deforming region, the physical state of the crust and upper mantle may vary laterally and vertically. However, a detailed 3D model of the region is lacking. The reliable determination of fault plane solutions is crucial if such a model is to be produced. On this basis, fault plane solutions have been determined from recent microearthquakes and small events to assess their reliability for use in tectonic interpretation. A search algorithm on first motion data and amplitude ratios and also a waveform-matching scheme were employed on data from our temporal network, operated on the western part of the island of Crete. There, a network of 47 three-component digital stations with an aperture of 60 km and an average station spacing of 5 km was operated in 1997. The majority of the shallow microearthquakes under Crete for which fault plane solutions were determined have a near horizontal T-axis oriented essentially E–W. Differences between well determined fault plane solutions from the search algorithm and the waveform-matching technique were significant (strike up to 45°, dip up to 10°, and slip up to 50°). Second, data of small events within the Hellenic subduction zone were obtained from recently installed broadband stations at local and regional distances and inverted for a deviatoric seismic moment tensor. Available solutions from other sources such as the Harvard group, EMSC, or SED show drastic differences in part. Owing to still limited azimuthal station coverage, the resulting fault plane solutions of small events have generally not been well constrained. The observed large variation of fault plane solutions for micoearthquakes and small events poses a caveat to tectonic interpretation in case of using data from a few stations only.  相似文献   

Precise two chronometer dating of Pleistocene travertine: The Th/U and Ra_ex/Ra(0) approach     

Jost Eikenberg  Guido Vezzu  Irene Zumsteg  Sixto Bajo  Max Ruethi  Georg Wyssling 《Quaternary Science Reviews》2001,20(18):129

In order to determine the geochemical evolution of a freshwater limestone cave system located in central Switzerland (Hell Grottoes at Baar/Zug,) young postglacial tufaceous limestone and travertine precipitates were investigated using the ²³⁰Th/²³⁴U ingrowth system. Additional analyses of further radionuclides within the ²³⁸U decay chain, i.e. ²²⁶Ra and ²¹⁰Pb, showed that the Th/U chronometer started with insignificant inherited ²³⁰Th over the entire formation period of the travertine setting (i.e. ²³⁰Th(0)=0). A contribution from detrital impurities with ²³⁰Th/²³⁴U in secular equilibrium could be precisely subtracted by applying isochron dating of cogenetic phases and recently formed travertine. The resulting precise ²³⁰Th/²³⁴U formation ages were found to be consistent with the geological stratigraphy and were furthermore used to demonstrate the applicability of the next geologically important chronometer in the ²³⁸U-decay series, based on decay of excess ²²⁶Ra normalized to the initial, i.e.²²⁶Ra_ex/²²⁶Ra(0). This system is suitable for dating phases younger than 7000 yr when the correction of a detritus component increasingly limits the precision of the ²³⁰Th/²³⁴U chronometer. Analytical solutions of the coupled ²³⁴U/²³⁰Th/²²⁶Ra radionuclide system predicted that the ²²⁶Ra_ex/²²⁶Ra(0) chronometer is independent of the actual ²³⁰Th activity build up from decay of ²³⁴U, if the systems starts with zero inherited ²³⁰Th(0). The data set confirmed this hypothesis and showed furthermore that the initially incorporated ²²⁶Ra excess must have remained almost uniform in all limestone over a period of at least 7000 yr, i.e. 4–5 half-lives of ²²⁶Ra. This is concluded because (i) the ²²⁶Ra_ex/²²⁶Ra(0) ages agreed well with those derived from ²³⁰Th/²³⁴U, (ii) all data plot within uncertainty on the ²²⁶Ra_ex/²²⁶Ra(0) decay curve and (iii) the atomic Ba/Ca ratio was found to be constant in the travertine material independent of the sample ages. Provided that such boundary conditions hold, ²²⁶Ra_ex/²²⁶Ra(0) should be applicable to materials which are suitable for ²³⁰Th/²³⁴U dating in sedimentology and oceanography, i.e. travertine, corals, phosphorites, etc., and should strongly support ²³⁰Th/²³⁴U for samples that have been formed a few thousand years ago.  相似文献   

Field studies of anoxic conditions in the Baltic Sea during the cruise of R/V <Emphasis Type="Italic">Professor Albrecht Penck</Emphasis> in July 2006     

G. Jost  B. Clement  S. V. Pakhomova  E. V. Yakushev 《Oceanology》2007,47(4):590-593

  相似文献   

Untersuchung über die Verteilung von Spurengasen in der freien Atmosphäre     

Hans-Walter Georgii  Dieter Jost 《Pure and Applied Geophysics》1964,59(1):217-224

Zusammenfassung Die vorliegende Arbeit behandelt die Ergebnisse von Messflügen zur Bestimmung der Konzentrationsverteilung von Spurengasen in der freien Atmosphäre. Auf Grund dieser Aufstiege war es erstmals möglich, den Gehalt der Atmosphäre an Schwefeldioxyd und Stickstoffdioxyd bis in Höhen von 6000 m zu erfassen. Die gewonnene mittelere Konzentrations-verteilung bietet die Basis zu Abschätzungen über den Haushalt und die mittlere Verweilzeit von SO₂ und NO₂ in der Troposphäre.

---

Summary This paper deals with the results of aircraft ascents for the measurement of the vertical distribution of atmospheric trace gases in the free atmosphere. The aircraft ascents permitted for the first time to measure the SO₂- and NO₂-concentration up to 6000 m. On the basis of the average distribution assumptions on the tropospheric budget of SO₂ and NO₂ as well as on the average tropospheric residence time of these gases were made.

  相似文献   

High resolution simulation of recent Arctic and Antarctic stratospheric chemical ozone loss compared to observations     

Om Prakash Tripathi  Sophie Godin-Beekmann  Franck Lefèvre  Marion Marchand  Andrea Pazmiño  Alain Hauchecorne  Florence Goutail  Hans Schlager  C. Michael Volk  B. Johnson  G. König-Langlo  Stefano Balestri  Fred Stroh  T. P. Bui  H. J. Jost  T. Deshler  Peter von der Gathen 《Journal of Atmospheric Chemistry》2006,55(3):205-226

Simulations of polar ozone losses were performed using the three-dimensional high-resolution (1^∘ × 1^∘) chemical transport model MIMOSA-CHIM. Three Arctic winters 1999–2000, 2001–2002, 2002–2003 and three Antarctic winters 2001, 2002, and 2003 were considered for the study. The cumulative ozone loss in the Arctic winter 2002–2003 reached around 35% at 475 K inside the vortex, as compared to more than 60% in 1999–2000. During 1999–2000, denitrification induces a maximum of about 23% extra ozone loss at 475 K as compared to 17% in 2002–2003. Unlike these two colder Arctic winters, the 2001–2002 Arctic was warmer and did not experience much ozone loss. Sensitivity tests showed that the chosen resolution of 1^∘ × 1^∘ provides a better evaluation of ozone loss at the edge of the polar vortex in high solar zenith angle conditions. The simulation results for ozone, ClO, HNO₃, N₂O, and NO _y for winters 1999–2000 and 2002–2003 were compared with measurements on board ER-2 and Geophysica aircraft respectively. Sensitivity tests showed that increasing heating rates calculated by the model by 50% and doubling the PSC (Polar Stratospheric Clouds) particle density (from 5 × 10⁻³ to 10⁻² cm⁻³) refines the agreement with in situ ozone, N₂O and NO _y levels. In this configuration, simulated ClO levels are increased and are in better agreement with observations in January but are overestimated by about 20% in March. The use of the Burkholder et al. (1990) Cl₂O₂ absorption cross-sections slightly increases further ClO levels especially in high solar zenith angle conditions. Comparisons of the modelled ozone values with ozonesonde measurement in the Antarctic winter 2003 and with Polar Ozone and Aerosol Measurement III (POAM III) measurements in the Antarctic winters 2001 and 2002, shows that the simulations underestimate the ozone loss rate at the end of the ozone destruction period. A slightly better agreement is obtained with the use of Burkholder et al. (1990) Cl₂O₂ absorption cross-sections.  相似文献