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The impact of macroalgae on mean and turbulent flow fields

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Journal of Hydrodynamics 2015年第3期27卷 427-435页

作者： THOMAS Robert E. MCLELLAND Stuart J. Department of geography Environment and Earth Sciences University of Hull

In this paper, we attempt to quantify the mean and turbulent flow fields around live macroalgae within a tidal inlet in Norway. Two Laminaria digitata specimens - 0.50 m apart were selected for detailed study and a profiling ADV was used to collect 45 velocity profiles, each composed of up to seven 0.035 m-high profiles collected for 240 s at 100 Hz, at a streamwise spacing of 0.25 m and cross-stream spacing of 0.20 m. To quantify the impact of the macroalgae, measurements were repeated over a sparser grid after the region had been completely cleared of algae and major roughness elements.

关键词： dealiasing laminaria digitata turbulence vectrino profiler velocity profile

Food security status in rural areas of Mizoram,Northeast India

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Journal of Mountain Science 2017年第4期14卷 795-805页

作者： Vishwambhar Prasad SATT Lalrinpuia VANGCHHIA Department of geography and Resources Management School of Earth SciencesMizoram UniversityAizawl 796004India

Rural areas practice subsistence of the Mizoram state, India agriculture where shifting cultivation dominates the farming systems. As a result, output from crops is very low and thus, the rural areas suffer from food insecurity. This paper analyses food security status in the rural areas of Mizoram and suggests the measures to attain food security. A case study of 16 villages, lying in all the eight districts of Mizoram, was conducted in 2014 and 1527 households （76%） out of total 2010 households were surveyed through purposive random sampling method. Structured questionnaire was constructed and questions on three food security components and 13 indicators were asked. We used Z score technique to calculate data and finally got a composite score of all the components of food security. Our result shows that food availability in the study villages is very less as composite score stands for ***3 whereas food accessibility is comparatively higher, mainly due to availability of fair price shops （mean value is one）, high agricultural working population （40.1%） and high literacy rate （70.6%）. Therefore, its composite score is 0.236. Food stability scores only -0.062 and finally overall food security stands for 0.178, which is inadequate. We have suggested that‘system rice intensification＇, which is already in practice, should be given priority. Adequate irrigation facilities, proper public distribution system, cultivation of fruits and vegetables, value addition in farm products and access to market may achieve food security.

关键词： Food availability Food accessibility Food stability Food security Mizoram

Sand dunes as potential sources of dust in northern China

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Science China earth sciences 2016年第4期59卷 760-769页

作者： Mark R SWEENEY LU HuaYu CUI MengChun Joseph A MASON FENG Han XU ZhiWei Department of earth sciences University of South Dakota Laboratory of earth Surface Process and Environment School of Geographic and Oceanographic Sciences Nanjing University Department of geography University of Wisconsin-Madison

While saltation bombardment of sand grains on a fine substrate can produce considerable dust, the well-sorted nature of sand dunes tends to preclude them from consideration as major dust sources. Recent research, however, has revealed that sand dunes can, in some cases, be large sources of dust. We used the PI-SWERL(Portable In-Situ Wind Erosion Laboratory) to measure in the field the potential of sand dunes and other desert landforms to emit particulate matter <10 μm(PM-10) dust in the Tengger, Ulan Buh, and Mu Us deserts of northern China. Combined with high resolution particle size measurements of the dune sand, an assessment of sand dunes as a dust source can be made. Large active transverse dunes tend to contain little to no stored PM-10, yet they produce a low dust flux. Coppice dunes stabilized by vegetation contain appreciable PM-10 and have very high dust emission potential. There is a positive correlation between the amount of PM-10 stored in a dune and its potential dust flux. Saltation liberates loose fines stored in dunes, making them very efficient dust emitters compared to landforms such as dry lake beds and washes where dust particles are unavailable for aeolian transport due to protective crusts or sediment cohesion. In cases where large dunes do not store PM-10 yet emit dust when active, two hypotheses can be considered:(1) iron-oxide grain coatings are removed during saltation, creating dust, and(2) sand grains collide during saltation, abrading grains to create dust. Observations reveal that iron oxide coatings are present on some dune sands. PI-SWERL data suggests that low dust fluxes from dunes containing no stored dust may represent an estimate for the amount of PM-10 dust produced by removal of iron oxide coatings. These results are similar to results from dunes in the United States. In addition, PI-SWERL results suggest that dust-bearing coppice dunes, which cover vast areas of China's sandy deserts, may become major sources of dust in the f

关键词： Coppice dunes Transverse dunes Dust PI-SWERL Desert

Cosmogenic ^(26)Al/^(10)Be Burial Dating of the Uplift Rate of Southern Qinling Mountains since the Middle Pleistocene

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Acta Geologica Sinica(English Edition) 2018年第4期92卷 1674-1675页

作者： LU Yiming SUN Xuefeng TU Hua ZENG Qiongxuan XU Xinghua school of geography and Ocean Science Nanjing University BGEG School of Earth Sciences China University of GeosciencesWuhan

Objective The Qinling Mountains （QM） in Central China is a natural harrier that corresponds to the boundary between the southern and northern climate and environment （Gong Hujun et al., 2017）. Northern QM is relatively steep, and southern QM is in contrast relatively low and gentle. Investigations have shown that the average uplift rate of northern QM since 17.8 Ma is approximately 0.19 mm/a （Yin Gongming et al., 2001）, whereas that of central QM since 0.36 Ma is approximately 0.32 mm/a （Wang Fei et al., 2004）. To date, however, few investigations have yet been conducted on the uplift rate of southern QM. Accordingly, we aim to obtain the uplift rate of southern QM by using the cosmogenic ^26A1/^10 Be burial dating method to determine the age of the highest river terrace on the southern slope of QM.

关键词： Be Burial Dating of the Uplift Rate of Southern Qinling Mountains since the Middle Pleistocene Cosmogenic QM Al

Analyzing Land-use Change in Farming-pastoral Transitional Region Using Autologistic Model and Household Survey Approach

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Chinese Geographical Science 2013年第6期23卷 716-728页

作者： ZHU Likai MENG Jijun MAO Xiyan Department of geography University of Florida Laboratory for earth Surface Processes School of Urban and Environmental SciencesPeking University

Land change science （LCS） strives to understand and model land-use change, which will further advance the understanding of multiple issues in the socio-ecological systems. Based on GIS/RS techniques, autologistic model, and household survey method, this study investigated major land use changes and their causes from 1978 to 2008 in Uxin Banner （county-level）, Inner Mongolia in China and then developed an understanding of the relationships between household livelihood and land-use pattern. Results showed that cultivated land increased from 1988 to 2000, and leveled offafter 2000. Built-up land increased stably for the period 1978 2008. The change of grassland and bare land differed among the three periods. From 1978 to 1988, grassland increased by 23.3%, and bare land decreased by 20.48%. From 1988 to 2000, bare land expanded by 1.7%, but grassland declined by 1.3%. From 2000 to 2008, an increase in grassland area by 1.8% was observed, but a decrease in bare land area by 9.0% was witnessed. The autologistic models performed better than logistic models as indicated by lower Akaike Information Criterion （AIC） values. Factors associated with human activities significantly correlated with the change of cultivated land, forest land, grassland, and built-up land. The produce prices and extensive cultivated land use are major issues in the farming area. This study suggests that completing land circulation systems and maintaining the stability of price are effective solutions. By contrast, reclamation and overgrazing are major concerns in the pastoral areas. Implementing environmental policies effectively, transferring population out of rural pastoral areas, and developing modem animal husbandry are effective ways to address these issues.

关键词： farming-pastoral transitional region land use change driving force livelihood autologistic model Uxin Banner(county-level) Inner Mongolia

An Uncertain Programming Model for Land Use Structure Optimization to Promote Effectiveness of Land Use Planning

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Chinese Geographical Science 2017年第6期27卷 974-988页

作者： LI Xin MA Xiaodong school of geography Geomatics and Planning Jiangsu Normal University Department of earth and Environmental sciences University of British Columbia

Land use structure optimization(LUSO) is an important issue for land use planning. In order for land use planning to have reasonable flexibility, uncertain optimization should be applied for LUSO. In this paper, the researcher first expounded the uncertainties of LUSO. Based on this, an interval programming model was developed, of which interval variables were to hold land use uncertainties. To solve the model, a heuristics based on Genetic Algorithm was designed according to Pareto Optimum principle with a confidence interval under given significance level to represent LUSO result. Proposed method was applied to a real case of Yangzhou, an eastern city in China. The following conclusions were reached. 1) Different forms of uncertainties ranged from certainty to indeterminacy lay in the five steps of LUSO, indicating necessary need of comprehensive approach to quantify them. 2) With regards to trade-offs of conflicted objectives and preferences to uncertainties, our proposed model displayed good ability of making planning decision process transparent, therefore providing an effective tool for flexible land use planning compiling. 3) Under uncertain conditions, land use planning effectiveness can be primarily enhanced by flexible management with reserved space to percept and hold uncertainties in advance.

关键词： land use structure optimization (LUSO) uncertainties flexibility land use planning decision support system effectiveness

Driving force behind global cooling in the Cenozoic: an ongoing mystery

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Science Bulletin 2015年第24期60卷 2091-2095页

作者： Huayu Lu school of geography and Ocean Science Nanjing University CAS Center for Excellence in Tibetan Plateau earth sciences

The stepwise cooling marks the long-time global climate change during the Cenozoic, particularly since the Oligocene/Eocene boundary. This climatic evolution has been punctuated by several warming such as the peak Cenozoic warmth at 52 Ma, the late Oligocene warming at ～25 Ma and the Mid-Miocene Climatic Optimum at 17–14 Ma. Concurring with the global temperature changes, the Asian paleoenvironment has been modulated by the global cooling and the tectonic uplift during the Cenozoic, but what have driven the global climatic changes remains unresolved. In this review paper, I hypothesize that a threshold CO_2 level in combination with favorable orbital configuration, ocean circulation,enhanced ice albedo and possible roles of silicate mineral and basalt weathering together facilitated the development of glaciations in the Cenozoic and the past temperature change. The synchronous variations between earth's surface temperature and atmospheric CO_2 level may indicate that the atmospheric CO_2 content is the direct driving force for the global climatic cooling, but this hypothesis needs testing by using high-resolution geological record and paleoclimatic modeling.

关键词： Global cooling Cenozoic era Asianpaleoclimate Asian deserts Chinese loess deposit

Asia dust production ramped up since latest Oligocene driven by Tibetan Plateau uplift

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National Science Review 2016年第3期3卷 271-274页

作者： Hongbo Zheng school of geography Science Nanjing Normal University CAS Center for Excellence in Tibetan Plateau earth sciences

Eolian dust is an integral component of the earth system dynamics,participating in a range of physical,chemical and biogeological processes of the earth system at various temporal and spatial scales[1](Fig.1).Great advance has been achieved in recent years in understanding eolian dust cycles through instrumental investigations and numerical modeling as well as

关键词： Asia dust production ramped up since latest Oligocene driven by Tibetan Plateau uplift must

Non-coordination in China′s Urbanization: Assessment and Affecting Factors

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Chinese Geographical Science 2013年第6期23卷 729-739页

作者： SUN Pingjun SONG Wei XIU Chunliang LIANG Zhenming school of geography sciences Northeast Normal University Department of geography and Geo-sciences University of Louisville

Urbanization is a comprehensive concept, a trinity process that population urbanization, economic urbanization and space urbanization, is based on the interactions and mutual influences among the in which, people are the central and leading players in this process, while economic activities serve as the driving force and space is the carrier-the physical or material setting as well as the product. So the coordination among these processes is crucial for a country or region＇s sustainable development. China is experiencing rapid growth of cities and a surge in urban population, with the basic national condition of many people and little land, which calls for a systematic study of the issue of coordinated urbanization from theoretical, methodological and practical perspectives. Based on the concept of urbanization and non-coordination of urbanization, this article built a quantitative method to identify and evaluate the urbanization and non-coordination of urbanization, and made an empirical analysis in China between 2000 and 2008. The results show that the non-coordination overall level of China＇s urbanization declined during the study period, because population urbanization, economic urbanization, and space urbanization exhibited different trajectories of change. This study also reveals that performance assessment system, household registration system, and urban land expropriation system, etc., are the main affecting factors. At the end, we put forward some suggestions to achieve sustainable development of China＇s urbanization from the aspects of improving the local government＇s obiective function, imolementing the urban plalming svstem, enforcing public particination asnects and so on.

关键词： non-coordination of urbanization coordinated development degree China