The year 2018 has been a landmark year for Vadose Zone Journal for several reasons.First of all, from 1 Jan. 2018, VZJ flipped from a subscription journal to a golden open access (OA) journal.This now makes the research published in VZJ accessible to a global readership, and it expands our visibility and impact beyond the vadose and critical zone research community.This flip went smoothly, and it was prepared and implemented in an excellent manner by our editorial office and the Tri-Societies.It could not have succeeded without the relentless support and engagement of Pamm Kasper, VZJ managing editor, and our publication system managers Lauren Coleman and Abby Morrison.We are also grateful for the support that we received from the board of the Tri-Societies and the Soil Science Society of America in making this change.Secondly, the international visibility and attractiveness of VZJ has continued to improve.The impact factor (IF) of VZJ for 2017 reached an all-time high of 2.7 since its beginning, and it increased by 0.7 compared with 2016.We are now again a Q1 journal in water research, and we are confident that we will become Q1 again in soil and environmental research in the next years.The reasons for the increased IF are several-fold, but key to this success is the high quality of papers that we have received in the last years, the establishment of update papers, as well as the publication of reviews that were very well received.Several review and update papers showed very high download rates for several months.
This study investigates the flow characteristics around a complex jacket-type foundation structure when subjected to steady current. The investigation is conducted through physical experiments and numerical simulations. A fully three-dimensional OpenFOAM model is implemented, solving the Unsteady Reynolds-averaged Navier–Stokes equations. In addition, physical experiments were carried out using Particle Image Velocimetry techniques to measure flow velocities around a joint element of the same jacket-type structure. High-resolution measurements were taken in several cross-sectional planes. The findings demonstrate a complex location-dependent flow pattern. Over the height of the jacket, the acceleration of flow and the vortex systems alter as the jacket narrows and distances between structural element change. Flow variations at different cross-sections along the jacket highlight the complex influence of specific jacket elements on the flow behavior. The inclination of piles, along with their varying diameters and arrangements, has a significant impact on the flow field. This makes the direct application of knowledge on the hydrodynamics around pile groups challenging. The geometry of the structure leads to an asymmetrical distribution of maximum shear stress amplification around the main piles, which influences scour depth expectations.
<p>Transport of gas components in the unsaturated zone and across the soil surface plays a role for transport of volatile contaminants, gases from pipe leaks or greenhouse gases. When estimating flow rates from the soil into the atmosphere, a good understanding of the transport processes is important. In general, component transport in the gas phase is considered to be mainly due to diffusion. However, the wind field above the soil surface can induce flow into the subsurface and influence transport and mass fluxes.</p><p>We present a study on gas component transport through dry and partially saturated soil into a free air flow above the soil surface, considering gas components of different density. Laboratory experiments in a quasi-2d sand tank were carried out. The tank was placed underneath a wind tunnel, and different wind velocities were used. Gases with different densities were injected with constant rate at an inlet port. Concentration distributions were measured continuously with sensors that were installed inside of the tank. After establishing a steady state concentration distribution, the gas injection was stopped and the decrease of gas concentrations inside the tank was monitored.</p><p>The experiments show that the concentration profiles under steady state gas injection depend on gas density and the different diffusion coefficients. They depend only slightly on the velocity of the overlaying wind field and the influence is mainly seen very close to the soil surface. The transient gas transport out of the soil, however, did not only depend on the different diffusion coefficients, but was clearly influenced by the wind field. The transient 2d concentration distribution fields illustrate that the wind field induced a flow field inside the tank that depends on the wind velocity and the component density and influences the gas component transport. The influence increases under partly saturated conditions.</p><p>To reproduce the transport correctly, it is necessary to capture the coupling between free flow and porous medium flow and the transport in the coupled flow. To do so, we use a fully coupled flow and transport model implemented into the environment DuMu<sup>x</sup> ((Dune for Multi-(Phase,Component, Scale, ...) flow and transport in porous media). It can be shown that including the coupling concept, the main features of the concentration distributions can be reproduced for both the steady state and the transient case. With the model it is also demonstrated, that although advective fluxes inside the porous medium introduced by the wind field (horizontal and lateral) are relatively small in comparison to the diffusive fluxes, they cause relevant changes in the concentration distribution and thus indirectly influence the mass fluxes inside the porous medium and across the soil-atmosphere interface.</p>
Large‐scale models of transient flow processes in the unsaturated zone require, in general, upscaling of the flow problem in order to capture the impact of heterogeneities on a small scale, which cannot be resolved by the model. Effective parameters for the upscaled models are often derived from second‐order stochastic properties of the parameter fields. Such properties are good quantifications for parameter fields, which are multi‐Gaussian. However, the structure of soil does rarely resemble these kinds of fields. The non‐multi‐Gaussian field properties can lead to strong discrepancies between predictions of upscaled models and the averaged real flow process. In particular, the connected paths of parameter ranges of the medium are important features, which are usually not taken into account in stochastic approaches. They are determined here by the Euler number of one‐cut indicator fields. Methods to predict effective parameters are needed that incorporate this type of information. We discuss different simple and fast approaches for estimating the effective parameter for upscaled models of slow transient flow processes in the unsaturated zone, where connected paths of the material may be taken into account. Upscaled models are derived with the assumption of capillary equilibrium. The effective parameters are calculated using effective media approaches. We also discuss the limits of the applicability of these methods.
Editors of several journals in the field of hydrology met during the Assembly of the International Association of Hydrological Sciences—IAHS (within the Assembly of the International Union of Geodesy and Geophysics—IUGG) in Prague in June 2015. This event was a follow-up of a similar meeting held in July 2013 in Gothenburg (as reported by 3). These meetings enable the group of editors to review the current status of the journals and the publication process, and share thoughts on future strategies. Journals were represented in the 2015 meeting through their editors, as shown in the list of authors. The main points on fostering innovation and improving impact assessment in journal publications in hydrology are communicated in this joint editorial published in the above journals. In the last few decades, the dominant practice of universities, governments, and research funding organizations in assessing individuals or research proposals has been to use the number of papers published—sometimes separating those in high-impact journals—and number of citations as the main benchmarks, rather than true innovation (including new ideas, original methods, discovery, and improved application of technology). This has resulted in consistently increasing pressure to publish in journals—the “publish-or-perish” syndrome. In turn, this has transformed the publication industry (e.g. with the creation of numerous for-profit publication vehicles) as well as the peer review system per se. Specifically, with the plethora of journals, “peer review […] is becoming a system that judges where work is published rather than whether the research is publishable (a ‘where rather than if’ process)” (8). In the majority of journals represented in this editorial, submissions have dramatically increased. As a response, some of the journals have increased the rate of desk rejections, i.e., rapid rejections by the editor without sending the papers out for peer review, with the objective of reducing the pressure on the review system. It is the common agreement of all editors that the peer-review system is a key component of the publication process and essential for scientific progress of the community. Maintaining the highest quality of the peer-review process is thus crucial. However, the system has several weaknesses. Some of its critics have characterized it in strong language, e.g., as a “non-validated charade whose processes generate results little better than does chance” (4), and a recent editorial Comment in a medical journal (5) stated, “The case against science is straightforward: much of the scientific literature, perhaps half, may simply be untrue.” After completing a systematic survey of more than 1000 manuscripts submitted to three elite medical journals, 9 concluded that “on the whole, there was value added in peer review,” even though “both errors of omission [rejecting a worthy article] and commission [publishing an unworthy article] were prominent.” Another symptom of the “publish-or-perish” syndrome is that research is becoming more fragmented. The same body of research is often split into a number of papers (a tactic sometimes referred to as “salami publishing”). Such tactics may improve individuals' citation counts and other bibliometric indices, but they also reduce their representativeness as indicators of scientific impact. The increasing number of publications, number of entries in the reference lists, and average number of authors per paper, have all markedly increased the total number of citations in recent years. Multi-author papers are mushrooming, going to several “kiloauthors” in some disciplines.1 Such papers may reflect large-scale collaborations within the community and therefore may be appropriate, but quite frequently one actually notes that their content does not justify the involvement of several scientists. Just sharing an opinion is not a sufficient scientific contribution to justify co-authorship of a paper. The above transformations make the review process less efficient, and amplify its weaknesses, thus making the identification of truly innovative papers more difficult, both during the peer review process and after publication. The poor ability to identify innovation is a known problem of the peer-review system. Scientists tend to be conservative in their assessments, i.e., favor mainstream and conventional wisdom, and are therefore less supportive of truly original research. A characteristic example is the paper by 2, one of the most cited hydrological papers ever (expected to exceed 5000 citations soon, according to data from Google Scholar), which was rejected by one journal before being accepted by another.2 The overloading of peers with review requests exacerbates the above weakness, so that modest papers may have low probability of rejection, while truly outstanding ideas are less likely to be recognized. A recent study showed that an increasing number of excellent papers were initially rejected (9). Likewise, published papers of outstanding quality may not always be as visible as they deserve. We believe there is a lot the hydrological community can do to improve the situation. We believe that raising awareness of the community about the problems is a first necessary step. Awareness of science's goal of the pursuit of truth and discovery (rather than the support of any non-scientific objectives) is essential. This is fully consistent with the objectives of the peer-review system. In order to address one of the main causes of the “publish-or-perish” syndrome, a change in the way science is evaluated may be necessary. Rather than counting the number of papers and citations, it would be preferable that selection committees, promotion panels, and review panels put on center stage the innovation and ideas in the scientific contributions of individuals and institutions. It is realized that this may entail more extensive efforts, as a thorough engagement in the actual science progress will be needed. Such a change could be facilitated by the journals (editors, reviewers, authors, scientific publishers) and bibliometric services highlighting novelty in the papers. Dedicated discussion forums and workshops are needed, perhaps during scientific conferences, and scientific associations should recognize the profile of scientists working toward this target. This movement towards a better appreciation of innovation in place of counting numbers is already implemented in a number of science councils and honor committees. Web publishing and web-based impact assessments will likely play a role in the future, but it is questionable how they could assist in putting innovation (quality) over numbers (quantity). Besides the huge increase in publications there is an inflation of evaluations. Research cannot and should not be measured as industrial production. Important results may require time for development, in particular if interdisciplinary approaches are followed, and early publication of unripe papers may hamper the progress of important contributions. Evaluations are necessary in cases of promotion or tenure, but should not excessively increase the pressure on scientists. A large number of authors makes it difficult to judge the contribution of each and every author. Scientists should be listed as authors only if they have justifiably contributed to the study, and the number of authors must be commensurate with the extent and importance of the study. Editors and reviewers should check whether the number of authors is justified. The dominance of the h-index as the principal evaluation metric of individuals has been one of the drivers of the surge of multi-authored papers. However, there are biases related to the independent count for each author. An extreme example from physics is the article by 1, where 2926 authors describe the ATLAS detector in its experimental cavern at CERN. The 1398 Google Scholar citations (as of 25 Jan. 2016) are counted 2926 times, resulting in a total of 4,090,548 counts. Even though citation metrics should only be a secondary criterion in research evaluation, there may be merits in modified metrics, e.g., replacing the standard h-index by a normalized index3 that distributes the total number of citations to the individual authors in some way (e.g. by assigning 0.48 = 1398/2926 citations to each author, instead of 1398, in our example). If such a modified index became the norm, it would probably help refocus collaboration among researchers towards the science interactions alone. All players in the peer-review process can help enhance the chances for outstanding papers to be published. Authors can help by practicing clarity, disclosure, and transparency of data, derivations, algorithms, argumentation, and presentation at large. Journal editors can help by clarifying the requirements for acceptance, by better defining the reviewers' roles and responsibilities, and by allowing for diversity, e.g., by publishing negative review comments along with a paper (provided the reviewers agree and are eponymous) and encouraging formal discussions (comments and replies). Reviewers can help by adhering to a structured approach of evaluating papers. There is, for example, no need for a positive answer to any of these questions: In contrast, an affirmative answer is needed for these: Additionally, other qualities of a paper should in fact favor publication, even though they are often regarded as reasons for rejection, for example: There is also a lot that our community can do to reduce the fragmentation and contribute to knowledge building and capitalization of the community as a whole. The social and medical sciences have a strong tradition of linking individual studies by meta-analyses and evidence synthesis (11; 12) and there is also increasing awareness in the physical sciences of a need for better synthesis (6). In our role as editors, we aim to support the synthesis efforts that build on earlier studies across all hydrology journals. There is a proposal to establish a jointly agreed protocol for meta-data that would be archived along with published papers, inspired by a similar initiative in the medical sciences (7). The protocol would apply to studies reporting on specific catchments and would include codified hydrological information, such as: World Meteorological Organization (WMO) Regions and Subregions, displayed by the Global Runoff Data Centre (http://www.bafg.de/SharedDocs/Bilder/Bilder_GRDC/wmo_regions.gif), that could be used to link research papers to each other. The editors welcome suggestions from the community for such a protocol (e.g., in the form of comments on this article). Suggestions for protocols that could apply to other types of studies are also welcome. It is likely that, over the longer term, many scientific journals (and research sponsors) will require full disclosure of all data and models used before acceptance of manuscripts. This will additionally facilitate synthesis and enhance the collaboration across research groups beyond long author lists. It will also help enhance the peer-review process, going beyond assessing the consistency of the results towards a test of the results through full repeatability of the studies (cf., 10). Research evaluation at large will also benefit from such a development to better appreciate excellence. The attitude of individuals within the scientific community to further science by adopting transparent approaches will remain critically important. Winston Churchill once said: “Democracy is the worst form of government, except for all those other forms that have been tried from time to time.” Similarly, the peer-review process is not perfect, but it provides a route toward unbiased, robust, and timely assessment of scientific thought before it becomes public and—importantly—before its application and use in decision support. The improvements suggested will help enhance the peer-review process, which, despite justified criticism, remains a highly valuable voluntary community service that contributes to the value of science in society and to the reliability of scientific results. We hope that, in addition, the improvements will help the hydrological community to grow from strength to strength in order to address the grand water challenges of the 21st century.
Core Ideas Gravity‐driven flow was studied in the presence of lenticular heterogeneity. The importance of finger impingement position on heterogeneities was emphasized. These experiments present a data set for testing of extended Richards' models. Prediction of infiltration in porous media is challenged by finger formation and unstable displacement of the wetting front. We present a systematic experimental study on the effect of packings and infiltration rates on unstable flow into initially dry porous media. We conducted small two‐ and three‐dimensional experiments where water contents were measured with neutron radiography and larger two‐dimensional experiments, which we evaluated by obtaining commonly used finger properties such as width and velocity from image analysis. Our results from experiments in macroscopically homogeneous packings were tested for correspondence with theoretical finger property predictions and are in good agreement. For the smaller experiments, water content profiles including “overshoots” at the finger tips as well as finger properties depending on the packing matched well results reported in the literature. For all homogeneous experiments, we found a strong dependence of finger properties on porosity. Homogeneous experiments served as reference cases for comparison with larger two‐dimensional experiments where heterogeneity was induced by block‐shaped inclusions. Unstable flow propagation in heterogeneous experiments was documented by inclusion fill rates in addition to finger properties. We found a multifaceted finger propagation behavior that depends on the impingement position of instabilities on an inclusion. Thereby, we are able to show that the location of the impingement on an inclusion is crucial to the filling rate of the inclusion and the propagation velocity of the finger. Results from the conducted experiments present a data set for testing of extended Richards' models.
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