The Fernow Experimental Forest,West Virginia,USA: Insights,datasets, and opportunities     

Luis Andrés Guillén  Mary Beth Adams  Emily Elliot  Jason Hubbart  Charlene Kelly  Brenden McNeil  William Peterjohn  Nicolas Zegre 《水文研究》2021,35(4):e14106

Long-term experimental watershed studies have significantly influenced our global understanding of hydrological processes. The discovery and characterization of how stream water quantity and quality respond to a changing environment (e.g. land-use change, acidic deposition) has only been possible due to the establishment of catchments devoted to long-term study. One such catchment is the Fernow Experimental Forest (FEF) located in the headwaters of the Appalachian Mountains in West Virginia, a region that provides essential freshwater ecosystem services to eastern and mid-western United States communities. Established in 1934, the FEF is among the earliest experimental watershed studies in the Eastern United States that continues to address emergent challenges to forest ecosystems, including climate change and other threats to forest health. This data note describes available data and presents some findings from more than 50 years of hydrologic research at the FEF. During the first few decades, research at the FEF focused on the relationship between forest management and hydrological processes—especially those related to the overall water balance. Later, research included the examination of interactions between hydrology and soil erosion, biogeochemistry, N-saturation, and acid deposition. Hydro-climatologic and water quality datasets from long-term measurements and data from short-duration studies are publicly available to provide new insights and foster collaborations that will continue to advance our understanding of hydrology in forested headwater catchments. As a result of its rich history of research and abundance of long-term data, the FEF is positioned to continue to advance understanding of forest ecosystems in a time of unprecedented change.  相似文献   

Transient streambed hydraulic conductivity in channel and bar environments,Loup River,Nebraska     

Jesse T. Korus  Wilhelm P. Fraundorfer  Troy E. Gilmore  Kelsey Karnik 《水文研究》2020,34(14):3061-3077

Streambed hydraulic conductivity (K) and vertical K (K _v) are key controls on groundwater and surface water exchange and biogeochemical fluxes through the hyporheic zone, but drivers of transient hydraulic properties in different fluvial environments are poorly understood. This study combines hydrogeology, geophysics, and sedimentology to reveal mechanisms of K and K _v transience in the upper 0.5 m of a sandy streambed during low discharge. Hydraulic tests (44 slug tests, 130 falling-head permeameter tests) and 130 grain-size analyses were repeated three times over 8 weeks on a 1,200 m² grid spanning: (a) a channel with continuously flowing water and mobile bed load; (b) an adjacent mid-channel bar that was stationary and infrequently submerged. Aerial photographs and ground-penetrating radar show scour and complete reworking of fluvial sediments in the channel. Bar sediments below the water table remained immobile, but infrequent flows of moderate discharge reworked the uppermost few centimetres of the bar top. Despite differences in sediment mobility and stream flow characteristics across environments, K and K _v exhibited order-of-magnitude differences in spatial heterogeneity and temporal variability in both the channel and bar. Mean K and K _v values in the channel were comparatively stable over time. In the immobile bar, mean K declined 20% and K _v declined 26% after increased discharge temporarily inundated the bar. Grain-size distributions were steady across both environments over time, but repeat geophysical surveys of the bar show a decrease in electrical conductivity, likely from porosity reduction. These findings suggest that sediment dynamics and stream flow characteristics in different streambed environments are important drivers of K transience during low discharge conditions. Specifically, pore clogging can be an important mechanism of transience over short durations (weeks to months) in immobile sediments subject to infrequent flows and minor reworking.  相似文献   

Über eine durch Raphidonema spiculiforme nov. spec. verursachte Wasserblüte und ihre experimentelle Untersuchung     

Wilhelm Vischer 《Aquatic Sciences - Research Across Boundaries》1941,9(1-2):108-127

Ohne Zusammenfassung mit 43 Abbildungen  相似文献   

Kurzer Bericht über die sedimentpetrographische Untersuchung zweier Lotkerne der Albatross-Expedition     

Dr. Friedrich Wilhelm Locher 《Contributions to Mineralogy and Petrology》1952,3(3):193-218

Ohne Zusammenfassung  相似文献   

Nordamerika     

Wilhelm Bierther 《International Journal of Earth Sciences》1948,35(2):106-115

Ohne Zusammenfassung  相似文献   

Fritz Drevermann ‡     

Wilhelm Salomon-Calvi 《International Journal of Earth Sciences》1932,23(5):283-288

Ohne ZusammenfassungViele der im folgenden verwerteten Angaben verdanke ich Frau Prof. Drevermann und Herrn Prof. Dr.Rudolf Richter. Einiges habe ich von ihnen wörtlich übernommen.  相似文献   

Bücher- und Zeitschriftenschau     

W. Salomon  Wilckens  Steinmann  Wilhelm Salomon  Donath 《International Journal of Earth Sciences》1928,19(5):425-432

Ohne Zusammenfassung  相似文献   

Simplification and Validation of a Spectral-Tensor Model for Turbulence Including Atmospheric Stability   总被引：1，自引：1，他引：0  

Abhijit Chougule  Jakob Mann  Mark Kelly  Gunner C. Larsen 《Boundary-Layer Meteorology》2018,167(3):371-397

A spectral-tensor model of non-neutral, atmospheric-boundary-layer turbulence is evaluated using Eulerian statistics from single-point measurements of the wind speed and temperature at heights up to 100 m, assuming constant vertical gradients of mean wind speed and temperature. The model has been previously described in terms of the dissipation rate \(\epsilon \), the length scale of energy-containing eddies \(\mathcal {L}\), a turbulence anisotropy parameter \(\varGamma \), the Richardson number Ri, and the normalized rate of destruction of temperature variance \(\eta _\theta \equiv \epsilon _\theta /\epsilon \). Here, the latter two parameters are collapsed into a single atmospheric stability parameter z / L using Monin–Obukhov similarity theory, where z is the height above the Earth’s surface, and L is the Obukhov length corresponding to \(\{Ri,\eta _\theta \}\). Model outputs of the one-dimensional velocity spectra, as well as cospectra of the streamwise and/or vertical velocity components, and/or temperature, and cross-spectra for the spatial separation of all three velocity components and temperature, are compared with measurements. As a function of the four model parameters, spectra and cospectra are reproduced quite well, but horizontal temperature fluxes are slightly underestimated in stable conditions. In moderately unstable stratification, our model reproduces spectra only up to a scale \(\sim \) 1 km. The model also overestimates coherences for vertical separations, but is less severe in unstable than in stable cases.  相似文献   

Multiple-Thread Model of a Prominence Observed by Sumer and eit on Soho     

Wiik  J.E.  Dammasch  I.E.  Schmieder  B.  Wilhelm  K. 《Solar physics》1999,187(2):405-426

A quiescent polar crown prominence was observed at Meudon in Hα and Ca ii lines, and by EIT and SUMER on board SOHO in UV lines from 9 to 10 March 1996. SUMER observed the prominence continuously in a scanning mode between 21:40 UT on 9 March, and 18:13 UT on 10 March, in the nitrogen line N v (λ1238) with a 1 arc sec² resolution. Altogether 190 prominence images (121×108 pixels) were obtained. These are presented in a movie. The prominence is highly dynamic. Large-scale features, such as mixed loop systems and dark cavities are changing on time scales of a few hours. Filamentary structure is evident and is changing within a few frames of the movie. A lifetime of 20–25 min for the fine structure has been found by the autocorrelation method. We have statistically analysed the three moments of the N v line in the prominence: line intensity, Doppler shift and linewidth, in the context of a multiple-thread model. We find that the data are consistent with a model where the prominence is assumed to be an ensemble of small threads. In the brightest parts of the prominence it is possible that there are many unresolved threads (15–20) along the line of sight with diameters smaller than a few hundred kilometers. The filling factor is probably very small and in that case the structures occupy only a fraction of the volume. Supplementary material to this paper is available in electronic form at http://dx.doi.org/10.1023/A:1005151015043  相似文献   

Recharge and Groundwater Flow Within an Intracratonic Basin,Midwestern United States          下载免费PDF全文

Samuel V. Panno  Zohreh Askari  Walton R. Kelly  Thomas M. Parris  Keith C. Hackley 《Ground water》2018,56(1):32-45

The conservative nature of chloride (Cl^?) in groundwater and the abundance of geochemical data from various sources (both published and unpublished) provided a means of developing, for the first time, a representation of the hydrogeology of the Illinois Basin on a basin‐wide scale. The creation of Cl^? isocons superimposed on plan view maps of selected formations and on cross sections across the Illinois Basin yielded a conceptual model on a basin‐wide scale of recharge into, groundwater flow within and through the Illinois Basin. The maps and cross sections reveal the infiltration and movement of freshwater into the basin and dilution of brines within various geologic strata occurring at basin margins and along geologic structures. Cross‐formational movement of brines is also seen in the northern part of the basin. The maps and cross sections also show barriers to groundwater movement created by aquitards resulting in areas of apparent isolation/stagnation of concentrated brines within the basin. The distribution of Cl^? within the Illinois Basin suggests that the current chemical composition of groundwater and distribution of brines within the basin is dependent on five parameters: (1) presence of bedrock exposures along basin margins; (2) permeability of geologic strata and their distribution relative to one another; (3) presence or absence of major geologic structures; (4) intersection of major waterways with geologic structures, basin margins, and permeable bedrock exposures; and (5) isolation of brines within the basin due to aquitards, inhomogeneous permeability, and, in the case of the deepest part of the basin, brine density effects.  相似文献