The Bronze Age occupation of the Black Sea coast of Georgia—New insights from settlement mounds of the Colchian plain     

Hannes Laermanns  Mikheil Elashvili  Giorgi Kirkitadze  Christopher P. Loveluck  Simon Matthias May  Daniel Kelterbaum  Revaz Papuashvili  Helmut Brückner 《Geoarchaeology》2024,39(3):335-350

Along the lower course of the Rioni and several minor rivers, more than 70 settlement mounds (local name: Dikhagudzuba) have been identified by field surveys and remote sensing techniques. They give evidence of a formerly densely populated landscape in the coastal lowlands on the Colchian plain (western Georgia) and have been dated to the Bronze Age. As yet, limited information is available on their internal architecture, the chronology of the different layers and their palaeoenvironmental context. Based on archaeological sources, remote sensing measurements of three mounds and sediment cores from one mound and its closer surroundings, our study presents a review of the relevant literature and reveals the internal structure, distribution and spatial extent of the mounds. Geochemical and sedimentological analyses of element contents (X-ray fluorescence) and granulometry helped to identify different stratigraphical layers and differentiate between natural facies and anthropogenic deposits; using the Structure-from-Motion technique the mounds' dimensions were calculated. The studied settlement mounds had relatively small dimension (varying from 30 to 100 m in diameter) and were similar in their stratigraphy. Measurement of elements that can identify types of human activity, notably metals and phosphorus, suggest changing intensities of human occupation, pastoral agriculture and metalworking through the occupation sequence. According to the ¹⁴C chronology, the formation of the settlements occurred during the first half of the second millennium B.C., which confirms the archaeological interpretation of their Bronze Age origin. The narrow age difference between the lowermost and uppermost anthropogenic layers indicates an intentional construction of the mounds, rather than a successive accumulation of construction debris due to the disintegration of loam bricks by weathering. Therefore, they are indeed mounds and not tells. It is most likely that the characteristic circular moats that surround them were the source of their construction material. Fluvial and alluvial processes in a warm and humid climate dominated the environment of the mounds.  相似文献   

Use of a Three-Domain Repesentation to Enhance GIS Support for Complex Spatiotemporal Queries   总被引：1，自引：0，他引：1  

May Yuan 《Transactions in GIS》1999,3(2):137-159

As the development of Geographic Information Systems (GIS) proceeds to advanced scientific and societal applications, there is an emerging need to enhance GIS support for complex spatiotemporal queries. Dynamic GIS representations (as opposed to static, map-based representations) that can integrate proper data elements in the production of geographic information are required. This paper demonstrates the use of a three-domain representation that facilitates compilation of higher-level information (such as frequency and rate) from preliminary data records (such as time and location) stored in a database. The three-domain representation is compared with snapshot, space-time composite, and spatiotemporal object models using a sample data set for forest transitions. While the three-domain representation is a normalization of these data models, it offers a conceptual alternative that enables GIS to represent spatiotemporal behaviors of geographic entities, in addition to entities as well as histories at locations as emphasized in most GIS data models. The comparison shows that the three-domain representation has combined the strengths of the space-time composite and spatiotemporal object models. Moreover, it enables aggregations of analytical use along with dynamic mappings between geographic concepts and locations, a distinct capability that takes GIS query processing beyond the level of information support offered by static map-based data models.  相似文献   

Impacts of Streambed Heterogeneity and Anisotropy on Residence Time of Hyporheic Zone          下载免费PDF全文

Suning Liu  Ting Fong May Chui 《Ground water》2018,56(3):425-436

The hyporheic zone (HZ), which is the region beneath or alongside a streambed, plays an important role in the stream's ecology. The duration that a water molecule or a solute remains within the HZ, or residence time (RT), is one of the most common metrics used to evaluate the function of the HZ. The RT is greatly influenced by the streambed's hydraulic conductivity (K), which is intrinsically difficult to characterize due to its heterogeneity and anisotropy. Many laboratory and numerical studies of the HZ have simplified the streambed K to a constant, thus producing RT values that may differ from those gathered from the field. Some studies have considered the heterogeneity of the HZ, but very few have accounted for anisotropy or the natural K distributions typically found in real streambeds. This study developed numerical models in MODFLOW to examine the influence of heterogeneity and anisotropy, and that of the natural K distribution in a streambed, on the RT of the HZ. Heterogeneity and anisotropy were both found to shorten the mean and median RTs while increasing the range of the RTs. Moreover, heterogeneous K fields arranged in a more orderly pattern had longer RTs than those with random K distributions. These results could facilitate the design of streambed K values and distributions to achieve the desired RT during river restoration. They could also assist the translation of results from the more commonly considered homogeneous and/or isotropic conditions into heterogeneous and anisotropic field situations.  相似文献   

Cover Image          下载免费PDF全文

Jan‐Hendrik May  He‐Qing Huang  Toshiyuki Fujioka  David Fink  Alexandru Codilean  Guo‐An Yu  Yuanxu Ma  Gerwin Wulf  Jing Gu 《地球表面变化过程与地形》2018,43(3):i-i

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Koster site archeology: Stratigraphy and landscape evolution. Edwin R. Hajic, 1990, Center for American Archeology Research Series,Volume 8, xv + 99 pp., $9.00 (paperbound)     

David W. May 《Geoarchaeology》1991,6(3):295-296

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Numerical modelling to evaluate the nitrogen removal rate in hyporheic zone and its implications for stream management     

Suning Liu  Ting Fong May Chui 《水文研究》2019,33(24):3084-3097

The hyporheic zone (HZ) plays a vital role in the stream ecosystem. Reactions in the HZ such as denitrification and nitrification have been examined in previous studies. However, no numerical model has yet been developed that can accurately simulate nitrogen concentration changes in the HZ, because the zones for the two reactions can change throughout the reactions. This study proposes a method of evaluating the nitrogen removal rate in the HZ through numerical modelling. First, a basic two‐dimensional numerical model coupling flow conditions with biochemical reactions is proposed to consider both nitrification and denitrification. The zones for different reactions are determined under the assumption that related environmental variables (i.e., the dissolved oxygen) will not change throughout the reactions. Next, to examine changes in environmental variables throughout the reactions, an improved model is proposed, and a method is developed for delineating the boundary between nitrification and denitrification zones and identifying a transition zone where either reaction might take place. However, more information about biochemical reactions in the HZ is required to use the improved model. To overcome this shortcoming, a new model that couples the basic model and genetic programming (GP) is proposed to optimize the simulation results of the basic model and allow for real‐time forecasting. The results show that the basic model obtains acceptable simulation results for nitrate concentration distribution in the HZ. The improved model performs better than the basic model, but the model coupling the basic model with GP performs best. In addition, the function of the HZ in nitrogen removal is examined through a case study of four scenarios, leading to the conclusion that the HZ has a higher nitrogen removal rate when water quality is neither too poor nor too good. Overall, this study enhances our understanding of the HZ and can benefit the restoration and management of HZs and streams in the face of the continual degradation caused by human activity.  相似文献   

Evaluating hydrologic performance of bioretention cells in shallow groundwater          下载免费PDF全文

Kun Zhang  Ting Fong May Chui 《水文研究》2017,31(23):4122-4135

Bioretention cells, which are generally effective in controlling surface runoff and recharging groundwater, have been widely adopted as low impact development practices. However, shallow groundwater has limited their implementation in some locations due to the potential problems of a reduction in surface runoff control, groundwater pollution, and continuous groundwater drainage through the underdrain. Many guidelines have established minimum requirements for the groundwater depth below bioretention cells, but they may not be optimized for certain environmental conditions and bioretention cell designs. This study made use of a variably saturated flow model to examine the hydrologic performance of a single bioretention cell in shallow groundwater with event‐based simulations, considering a wide range of initial groundwater depths, media and in situ soil types, surface runoff loads, and underdrain sizes. Performance indicators (e.g., runoff reduction, time for infiltrated water to reach the bioretention cell bottom and the groundwater table, and height and dissipation time of groundwater mound) were evaluated to examine the processes of runoff generation, the formation and dissipation of groundwater mounds, and the bioretention cell's performance in a shallow groundwater environment. The most influential factors were the initial groundwater depth, the hydraulic conductivity of the media soil, and the rainfall runoff load. With a deeper initial groundwater table, infiltrated water took longer to reach the bioretention cell bottom and groundwater table. Groundwater mounds, however, took longer to dissipate even though they were smaller. The groundwater quality can be better protected if relatively less‐permeable soil types (e.g., sandy loam) are used as the media, although it may compromise the performance in runoff quantity control. However, only very high surface runoff loads would cause concerns regarding a reduction in runoff quantity control and possible groundwater contamination due to the shallow groundwater. A distance of 1.5–3 m between the bioretention cell bottom and the groundwater table is generally sufficient. The results of this study could help to guide the planning and design of bioretention cells in areas of shallow groundwater.  相似文献   

New OB-association in Pup — CMa     

A. L. Gyulbudaghian  J. May 《Astrophysics》1999,42(2):132-139

A new method of determination of distances to stellar associations is proposed. This method is based on the measurements of mean thicknesses of globules of the systems of dark globules connected with that association. It is shown that the method is in good agreement with other known methods. A new grouping of OB stars in Pup-CMa is found. It is shown that this grouping has properties characteristic for OB-associations: the stars of that grouping have similar distances, similar radial velocities, the grouping is connected with molecular clouds, with Herbig-Haro objects, and cometary nebulae. All these results are in favour of this grouping to be a new OB-association. We named that association OB-association Pup-CMa. The preliminary results of¹²CO observations of molecular clouds connected with that association are also given. The radial velocities of these clouds are in good agreement with the mean radial velocity of stars in the association in Pup-CMa. Translated from Astrofizika, Vol. 42, No. 2, pp. 179–188, April–June, 1999.  相似文献   

Space-time spectra of the atmospheric intraseasonal variability in the extratropics and their dependency on the El Niño/Southern Oscillation phenomenon: model versus observation     

W. May 《Climate Dynamics》1999,15(5):369-387

By comparing the results obtained from two sets of simulations with the ECHAM3 and the ECHAM4 atmospheric general circulation models with results derived from the ECMWF re-analyses, we not only investigate the models’ capability to reproduce aspects of the intraseasonal variability in the extratropics realistically, but also evaluate the impact of the changes between the two different versions of the ECHAM model. Moreover, we assess the impact of the marked variations of sea surface temperatures in the tropical Pacific associated with the El Niño/Southern Oscillation (ENSO) phenomenon on the characteristics of the intraseasonal variability in the midlatitudes. Both models realistically reproduce many aspects of the intraseasonal variability in the extratropics, i.e. the partition of the variability into the contributions of the transient cell and of the stationary and transient eddies and its seasonal variation, and also the spectral distribution of the contribution of the transient waves to the intraseasonal variability. The most severe deficiency of the models is a considerable underestimation of the contributions of the transient waves to the intraseasonal variability, mainly in the low-frequency part of the spectrum. In the recent version of the ECHAM model (ECHAM4) some of the model’s shortcomings in simulating the intraseasonal variability realistically, in particular those in the Southern Hemisphere, are noticeably reduced compared to the previous version (ECHAM3). Yet some aspects are more realistically captured by ECHAM3. Both the ECMWF re-analyses and the two sets of simulations with the ECHAM models reveal a distinct impact of the ENSO phenomenon on the characteristics of the intraseasonal variability within the extratropics in boreal winter. In the Northern Hemisphere the most prominent effect is that the activity of the stationary waves is enhanced during El Niño events at the expense of the transient waves. In the Southern Hemisphere, on the other hand, all the different contributions to the variance on intraseasonal time scales (transient cell, transient and stationary eddies) are stronger during El Niño than during La Niña events. Concerning the transient waves, this mainly reflects changes in the low-frequency part of the spectrum associated with the activity of ultra-long planetary waves.  相似文献   

Livelihood and vulnerability in the wake of Typhoon Yolanda: lessons of community and resilience     

Eadie  Pauline  Atienza  Maria Ela  Tan-Mullins  May 《Natural Hazards》2020,103(1):211-230

Natural Hazards - Livelihood strategies that are crafted in ‘extra-ordinary’ post-disaster conditions should also be able to function once some semblance of normalcy has resumed. This...  相似文献