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Sample records for northwestern south china

  1. Crustal structure and extension mode in the northwestern margin of the South China Sea

    NASA Astrophysics Data System (ADS)

    Gao, Jinwei; Wu, Shiguo; McIntosh, Kirk; Mi, Lijun; Liu, Zheng; Spence, George

    2016-06-01

    Combining multi-channel seismic reflection and gravity modeling, this study has investigated the crustal structure of the northwestern South China Sea margin. These data constrain a hyper-extended crustal area bounded by basin-bounding faults corresponding to an aborted rift below the Xisha Trough with a subparallel fossil ridge in the adjacent Northwest Sub-basin. The thinnest crust is located in the Xisha Trough, where it is remnant lower crust with a thickness of less than 3 km. Gravity modeling also revealed a hyper-extended crust across the Xisha Trough. The postrift magmatism is well developed and more active in the Xisha Trough and farther southeast than on the northwestern continental margin of the South China Sea; and the magmatic intrusion/extrusion was relatively active during the rifting of Xisha Trough and the Northwest Sub-basin. A narrow continent-ocean transition zone with a width of ˜65 km bounded seaward by a volcanic buried seamount is characterized by crustal thinning, rift depression, low gravity anomaly and the termination of the break-up unconformity seismic reflection. The aborted rift near the continental margin means that there may be no obvious detachment fault like that in the Iberia-Newfoundland type margin. The symmetric rift, extreme hyper-extended continental crust and hotter mantle materials indicate that continental crust underwent stretching phase (pure-shear deformation), thinning phase and breakup followed by onset of seafloor spreading and the mantle-lithosphere may break up before crustal-necking in the northwestern South China Sea margin.

  2. Sequence stratigraphy and continental margin development of the northwestern shelf of the South China Sea

    SciTech Connect

    Chen, P.P.H. ); Zhi Yuong Chen; Qi Min Zhang )

    1993-05-01

    Based on the sequence stratigraphic analyses of the Tertiary in the northwestern continental margin of the South China Sea, this paper summarizes the regional tectonics and their influences on the basin developments and discusses the systems tract distributions through the continental margin growth. The study area is underlain by two Tertiary basins separated by a major basin boundary fault across which two distinctly different basin structural styles developed. The Qiongdongnan basin shows characteristic rift structures and is closely related to the opening of the South China Sea. The Yinggehai basin is filled with thick Neogene monoclines overlying basement without apparent rift structures. The Yinggehai's genesis has been linked to the tectonism along the Red River suture zone. The margin development is characterized by depositional environments of sediment influx constantly exceeding accommodation space. Under these environments, the highstand deltas frequently developed near shelf edges, where vertically stacked shallow water sands of both highstand deltas and lowstand wedges/deltas could produce favorable exploration targets. High rates of sedimentation in the study area allow the identification of fourth-order cyclicity in the Quaternary. Regional sequence stratigraphic correlations suggest that many sequence boundaries appear to be synchronous, but not all boundaries exist in all basins along the eastern and southern continental margins of mainland China. The margin evolved through the repeated development of lowstand fans, lowstand wedges, transgressive systems tracts, and highstand deltas. Prior to the Pliocene, the shelf was sourced both from Vietnam and Hainan Island and, as a result, two shelf margins developed. The southwestern margin stopped growing in the late Miocene, and the northern margin continued to prograde with possible additional sediment inputs through the Red River system in the Quaternary. 29 refs., 22 figs.

  3. On generation and evolution of seaward propagating internal solitary waves in the northwestern South China Sea

    NASA Astrophysics Data System (ADS)

    Xu, Jiexin; Chen, Zhiwu; Xie, Jieshuo; Cai, Shuqun

    2016-03-01

    In this paper, the generation and evolution of seaward propagating internal solitary waves (ISWs) detected by satellite image in the northwestern South China Sea (SCS) are investigated by a fully nonlinear, non-hydrostatic, three-dimensional Massachusetts Institute of Technology general circulation model (MITgcm). The three-dimensional (3D) modeled ISWs agree favorably with those by satellite image, indicating that the observed seaward propagating ISWs may be generated by the interaction of barotropic tidal flow with the arc-like continental slope south of Hainan Island. Though the tidal current is basically in east-west direction, different types of internal waves are generated by tidal currents flowing over the slopes with different shaped shorelines. Over the slope where the shoreline is straight, only weak internal tides are generated; over the slope where the shoreline is seaward concave, large-amplitude internal bores are generated, and since the concave isobaths of the arc-like continental slope tend to focus the baroclinic tidal energy which is conveyed to the internal bores, the internal bores can efficiently disintegrate into a train of rank-ordered ISWs during their propagation away from the slope; while over the slope where the shoreline is seaward convex, no distinct internal tides are generated. It is also implied that the internal waves over the slope are generated due to mixed lee wave mechanism. Furthermore, the effects of 3D model, continental slope curvature, stratification, rotation and tidal forcing on the generation of ISWs are discussed, respectively. It is shown that, the amplitude and phase speed of ISWs derived from a two-dimensional (2D) model are smaller than those from the 3D one, and the 3D model has an advantage over 2D one in simulating the ISWs generated by the interaction between tidal currents and 3D curved continental slope; the reduced continental slope curvature hinders the extension of ISW crestline; both weaker stratification

  4. Weathering characteristics of the Lower Paleozoic black shale in northwestern Guizhou Province, south China

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Zhang, Jinchuan; Tang, Xuan; Yang, Chao; Tang, Shuai

    2016-07-01

    The northwestern Guizhou in the Yangtze Craton of south China has a tremendous potential of shale gas resource. In this paper, we present results from major and trace elements, total organic carbon, mineralogical composition analysis and petrophysical parameters to characterise shale weathering features. Further, the differences of black shale between underground and outcrops have also been presented to examine the changes of black shale after weathering. Our results show that the trace elements of shale have varying degrees of loss in the weathering leaching process, both in Niutitang shale and Longmaxi shale, the loss of B, V, Ni, Cu, Zn and Ba is obvious, but the element migration quantity in the former is greater than in the latter. Decomposition of minerals such as pyrite, feldspar and calcite result in the leaching of Na, Ca, Mg and Fe. The loss rate of total organic carbon (TOC) in black shales ranges from 18% to 70% with an average of 43%; moreover, the loss of organic carbon in samples with high TOC content is larger than in those samples with low TOC content. Results following the testing of porosity and permeability show that porosity increases significantly after weathering but permeability changes little. Furthermore, the increment of porosity is greater in the Niutitang shale (with more sulphide minerals) than in the Longmaxi shale, suggesting that the oxidation of sulphide minerals may have led to the formation of an acidic environment, causing the other minerals in the black shale to weather more quickly, thus resulting in increased porosity. The content of clay minerals in the core samples is slightly lesser than the outcrop samples, but the TOC content in the core samples is greater and has a larger specific surface area. This suggest that the TOC content played a decisive role on the specific surface area of shale. In addition, changes in the black shale caused by the weathering process mainly depend on the mineral composition and the TOC content

  5. Rifting of the north-western South China Sea Basin from MCS images

    NASA Astrophysics Data System (ADS)

    Ranero, Cesar R.; Cameselle, Alejandra L.; Franke, Dieter; Barckhausen, Udo

    2014-05-01

    We have reprocessed about 2250 km of multichannel seismic reflection data collected during cruise Sonne 49 across the NW South China Sea. We present images across four regional lines that cross the outer continental shelf and slope, and extend into the deep-water basin. The seismic images are of high quality and show the crustal structure from clear base-of-the-crust reflections to continuous top-of-basement reflections and a well imaged syn-rift and post rift stratigraphy and intrusive magmatic layering. In addition, fault reflections in the basement are also common. The crystalline basement and sediment strata display a series of structures that change laterally from the continental shelf to the deep-water basin and that have been used to define a continental domain, an abrupt continent to ocean transition and an oceanic domain. Existing wide-angle data coincident with our lines support our interpretation. The style of continental extension, the structures defining the continent to ocean transition, and the distribution of oceanic crust in the basin has been used to propose a tectonic model of the formation of the NW South China Sea continental margin. The data document the three-dimensional temporal evolution of the interplay between rifting processes and seafloor spreading leading to the current structural configuration.

  6. Summer upwelling and thermal fronts in the northwestern South China Sea: Observational analysis of two mesoscale mapping surveys

    NASA Astrophysics Data System (ADS)

    Jing, Zhiyou; Qi, Yiquan; Du, Yan; Zhang, Shuwen; Xie, Lingling

    2015-03-01

    Persistent coastal upwelling and upwelling-induced thermal fronts in the northwestern South China Sea are investigated using satellite measurements, two intensive mesoscale mapping surveys and three bottom-mounted ADCPs. The results indicate that pronounced surface cooling and upwelling-related fronts with a width of 20-50 km occur around Hainan Island and persist through the summer upwelling season. Driven by the prevailing southwesterly monsoon, the subsurface cooling band is ˜6°C colder than the water offshore of the East Coast, where the thermal gradients are generally more than 0.1°C/km. The cold and nutrient-rich coastal water is identified to be derived primarily from the deep water of the outer shelf. At the same time, the spatial structure of the upwelling and thermal front, as well as the upwelling-related coastal currents, is significantly regulated by wind forcing. A prominent lagged correlation between the moored temperature records and alongshore wind stress is detected in the East Coast. The correlation coefficient is -0.8 with the temperature lagging behind wind stress by 2.2 days, indicating that the cooling band off the East Coast is dominated mostly by the alongshore southwesterly monsoon during the upwelling season.

  7. Observation of near-inertial internal waves on the continental slope in the northwestern South China Sea

    NASA Astrophysics Data System (ADS)

    Zheng, Jie; Tian, Jiwei; Liang, Hui

    2017-04-01

    Based on nearly 3 months of moored acoustic Doppler current profiler records on the continental slope in the northwestern South China Sea (SCS) in 2006, this study examines temporal and vertical characteristics of near-inertial internal waves (NIW). Rotary frequency spectrum indicates that motions in the near-inertial frequency are strongly polarized, with clockwise (CW) energy exceeding counterclockwise (CCW) by about a factor of 10. Wavelet analysis exhibits an energy peak exceeding the 95% confidence level at the frequency of local inertial during the passage of typhoon Xangsane (24 September to 4 October). This elevated near-inertial kinetic energy (NIKE) event possesses about a 4 days delay correlation with the time integral of energy flux induced by typhoon, indicating an energy source of wind. Further analysis shows that the upward phase velocity of this event is 3.8 m h-1 approximately, corresponding to a vertical wavelength of about 125 m if not taking the redshift of local inertial frequency into account. Rotary vertical wavenumber spectrum exhibits the dominance of clockwise-with-depth energy, indicating downward energy propagation and implying a surface energy source. Dynamical modes suggest that mode 1 plays a dominant role at the growth stage of NIW, whereas major contribution is from higher modes during the penetration of NIKE into the ocean interior.

  8. The research on typhoon wave spectrum in northwestern South China Sea

    NASA Astrophysics Data System (ADS)

    Shi, Hongyuan; Cao, Xuefeng; Wen, Xianhua; Shi, Maochong; Zhao, Dongliang; Guo, Peifang

    2017-02-01

    Based upon the one-year wind wave measurement data, collected from the South China Sea (SCS) at coordinates 20° 36.298'N, 110°45.433'E. by Acoustic Wave And Current (AWAC), we analyzed the wave characteristics and concluded that the most common wave direction was E and the second most common direction was ENE, the mean and the maximum values of significant height was 1.2 m and 4.36 m, respectively. The mean period was 4.0 s. We also evaluated the wave spectrums under conditions existing in three typhoons: Rumbi, Jeti and Utor. We found that unimodal spectrums occurred more often than others, and the maximum spectrum peak was 30.7911 m2 s. The minimum peak frequency was 0.0625 Hz, and the mean peak frequency was 0.126 Hz. The wave period is important for the design of marine structures, especially the position of peak frequency had a great influence on the stress calculation. Spectral analysis showed that the values of peak frequency distributed between 0.063 Hz and 0.217 Hz, with the mean value 0.114 Hz. We fit the normalized spectrum with 6 theoretical spectral models, out of which, the Wen spectrum, JONSWAP spectrum and Wallops spectrum were proved to give the best fit. What distinguished the Wen Spectrum from the rest was that it does not rely on the measured spectrum for parameter estimation. Hence, we recommend that the Wen spectrum should be widely used in marine construction.

  9. Mesozoic hydrocarbon source rock studies of north Tarim, south Junggar, and Turpan basins, Xinjiang Uygur autonomous region, northwestern China

    SciTech Connect

    Hendrix, M.S.; Xiao, Z.; Liang, Y.; Graham, S.A.; Carroll, A.R.; Chu, J.; McKnight, C.

    1989-03-01

    Ongoing outcrop and accompanying pyrolysis studies of Mesozoic strata of the north Tarim, south Junggar, and Turpan retroarc foreland basins, northwestern China, have demonstrated the existence of potential oil-prone and gas-prone petroleum source rocks. Lithologies include Jurassic coals from all three basins and Triassic coals from Tarim. Jurassic coals collected from the Mesozoic depocenters of the Junggar and Tarim basins are oil prone, yielding S/sub 2//S/sub 2+3/ values that range from 0.80 to 0.99 and average 0.96, hydrogen index (HI) values that range from 117.9 to 213.4 and average 150.8, and oxygen index (OI) values that range from 1.1 to 31.6 and average 7.67. In contrast, Triassic coals of Tarim and Jurassic coals of Turpan contain more conventional type III gas-prone kerogens and yield S/sub 2//S/sub 2+3/ values ranging from 0.04 to 0.52 and averaging 0.22, HI values ranging from 3.2 to 130.2 with a mean of 33.6, and OI values ranging from 30.9 to 223.7 and averaging 115.9. Coals of all three basins are slightly immature to mature with respect to oil generation, as indicated by T/sub max/ values ranging from 425/degrees/ to 449/degrees/C (average = 343/degrees/C) and vitrinite reflectance values ranging from 0.51 to 0.64 (average = 0.57). Thus, given the widespread abundance and significant thicknesses of Mesozoic and especially Jurassic coals in all three basins, it is very likely that Mesozoic contributions to Xinjiang's oil and gas reserves are significant. This is particularly important in the north Tarim basin, where recent Chinese oil and gas discoveries have been made and the existence of significant pre-Mesozoic source beds remains unproven.

  10. Using zircon U-Pb ages to constrain the provenance and transport of heavy minerals within the northwestern shelf of the South China Sea

    NASA Astrophysics Data System (ADS)

    Zhong, Lifeng; Li, Gang; Yan, Wen; Xia, Bin; Feng, Yuexing; Miao, Li; Zhao, Jianxin

    2017-02-01

    Numerous ore-grade heavy mineral placer deposits occur in the northern South China Sea region. Previous studies on these deposits have focused on the heavy-mineral ore resources themselves, but the provenance and transport pathways of these heavy minerals are poorly constrained. This paper presents U-Pb ages of detrital zircons from sediments within the northwestern shelf of the South China Sea, and uses this new dataset to determine the provenance and transport pathway of the sediments. Zircons in sediments from ten areas of the northwestern shelf exhibit distinct age populations, suggesting that they have multiple provenances. Zircons in sediments from the Pearl River Mouth, Shangchuan Island, and Moyang River Mouth areas all have an obvious peak of Mesozoic ages, indicating that they have similar sediment provenances; i.e., mainly from the Pearl River, and to a lesser degree from the Moyang River. Zircons in sediments from the areas around the Jian River Mouth and Leizhou Bay, and off Hainan Island have an early Paleozoic age, suggesting that the sediments predominantly originate from the Yunkai massif. Zircons of the sediments from the remaining four areas, the Leiqiong Strait, Wanquan River Mouth, Qiongdongnan, and the Outer Shelf, have Yanshannian and Indosinian age peaks in addition to an obvious early Paleozoic population, implying mixed provenances, including the Yunkai massif and Hainan Island. The sediment transport may have involved two hydrodynamic conditions in two distinct stages. First, the Guangdong Longshore Current carried the river sediments to where they dispersed in the inner shelf; subsequently, wave-induced strong currents further transported sandy sediments southeastward to the outer shelf. In addition to explaining the provenance and transport pathways of heavy minerals within the northwestern shelf of the South China Sea, these results provide new information relevant to exploration for heavy-mineral placer deposits.

  11. Seismic geomorphology of the Lobed-channel System of Upper Miocene Huangliu Formation, Yinggehai Basin, Northwestern South China Sea

    NASA Astrophysics Data System (ADS)

    Liu, H.

    2016-02-01

    Three-dimensional seismic data have been widely used in interpreting ancient river systems and their associated sediment deposits. Thin-bed reservoirs of lobed-channel system in lithostratigraphic units of Dongfang (DF) area are one of the major study areas for reservoir growth in the Yinggehai basin of northwestern South China Sea. Although it is understood that the transport mechanics of parent substrate and alluvium determine the morphology of channel for lobed-channel system, the transport mechanism and regional gradient are relatively poorly understood. This study is focused on the application of various techniques in seismic geomorphology to the Yinggehai Basin at paleo-water-depth of 120m to assess influences of regional gradient and relative sea level change on lobed-channel palaeogeomorphology in shallow-water environments. The Vietnam paleo-Blue River, which located at south of modern Red River, flowed through DF area and transported turbidity deposit to DF area in the coastal environment. In 3-D seismic survey area, four fifth-order sequences in first member of upper Miocene Huangliu formation were identified using well and seismic data. Seismic inversion and 90° phasing of seismic data were used to convert seismic traces to pseudolithologic logs. Stratal slicing made it possible to interpolate and extrapolate well-data-derived sequence and identify submarine fan, channel fill, lobes and overbank deposit. Strata slices suggested that sea-floor slopes exerted main influence on channel morphology. Specifically, DF13-1 block had high gradient, which mainly distributed mud-sand-rich lobes. However, DF13-2 block established low gradient, which mostly indicated sand-rich braided channels. The values of sinuosity, channel widths, meander-belt widths in DF13-2 block are all greater than these in DF13-1 block. In addition, results of carbon isotope measurements and foraminiferal research of two blocks suggest that paleo sea level in DF13-2 block (30m 150m) was

  12. Stable isotope composition of precipitation in the south and north slopes of Wushaoling Mountain, northwestern China

    NASA Astrophysics Data System (ADS)

    Zongxing, Li; Qi, Feng; Song, Yong; Wang, Q. J.; Yang, Jiao; Yongge, Li; Jianguo, Li; Xiaoyan, Guo

    2016-12-01

    A study of spatial and temporal variability of precipitation isotope composition on the southern and north slopes of Wushaoling Mountain was conducted in order to explore the processes influencing its evolution. The analysis indicated that the isotopic composition, the slopes and intercepts of Local Meteroic Water Lines, altitude gradients and temperature effect are higher on the north slope than those on the south slope. The d-excess showed an increase from lower to higher altitudes, and the altitude gradients changed with season. The correlation coefficients between δ18O and d-excess decreased with increasing altitude due to weakening sub-cloud evaporation. Westerly wind principally dominates Wushaoling Mountain, so the relatively negative stable isotope values observed are related to the long distance transportation of water vapor in spring and winter. In summer and autumn, the locally strong sub-cloud evaporation cause relatively higher δ18O and lower d-excess. The results suggested that the sub-cloud evaporation has enriched the δ18O composition by 23%, 23%, 32%, 42% and 29% in May, June, July, August and September, respectively. In some circumstances, δ18O and δD were depleted at the end of multi-days rainfall events due to the rainout process. In addition, monsoonal moisture caused some negative δ18O in summer when an enhanced cyclonic circulation had developed on Tibetan Plateau. The study enhances the knowledge of isotopic evolution of precipitation and provides a basis for further study of isotopic hydrology in arid regions.

  13. Sediment provenance and paleoenvironmental changes in the northwestern shelf mud area of the South China Sea since the mid-Holocene

    NASA Astrophysics Data System (ADS)

    Xu, Fangjian; Hu, Bangqi; Dou, Yanguang; Liu, Xiting; Wan, Shiming; Xu, Zhaokai; Tian, Xu; Liu, Zhaoqing; Yin, Xuebo; Li, Anchun

    2017-07-01

    The late Quaternary paleoceanography and paleoenvironment of the South China Sea (SCS) have been well reconstructed over the last decade. In contrast, the provenance of the terrigenous sediments that have accumulated in the northwestern continental shelf mud area remains enigmatic. This study investigated the provenance of these sediments and the paleoenvironmental changes archived in Core X2 via the analysis of geochemical elements, grain size, and accelerator mass spectrometry (AMS) 14C ages. Based on the upper continental crust (UCC)-normalized REE patterns and REE fractionation parameters, southwestern and western Taiwanese rivers and the Pearl River were identified as the main sources of the fine-grained sediment deposited in the northwestern shelf mud area off Hainan Island. This finding further confirms the long-distance transport (> 1000 km) of fine-grained sediment from Taiwanese rivers to the northern SCS shelf and slope. Obvious changes in the grain size and Chemical Index of Alteration (CIA) record occurred at approximately 4.0 cal kyr BP and were likely caused by increased Hainan Island inputs due to sea level changes.

  14. Effect of a fast-moving tropical storm Washi on phytoplankton in the northwestern South China Sea

    NASA Astrophysics Data System (ADS)

    Zhao, Hui; Pan, Jiayi; Han, Guoqi; Devlin, Adam T.; Zhang, Shuwen; Hou, Yijun

    2017-04-01

    Tropical cyclones may augment nutrients in the ocean surface layer through mixing, entrainment, and upwelling, triggering phytoplankton blooms in oligotrophic waters such as the South China Sea (SCS). Previous studies focused mainly on responses of marine environments to strong or slow-moving typhoons in the SCS. In this study, we analyze variations of chlorophyll a (Chl a) and oceanic conditions in the continental shelf region east of Hainan Island during the fast-moving tropical storm Washi and investigate its influences on phytoplankton bloom and related dynamic mechanisms. Results indicate that there was significant variation of Chl a concentration in the continental shelf region, with low values (about 0.1 mg m-3) before the storm and a 30% increase after the storm. This increase was spatially variable, much larger nearshore than offshore. Power spectral analysis of Acoustic Doppler Current Profiler (ADCP) data at a shelf site near the study region reveals strong near-inertial oscillations (NIOs) in the upper layer, with a period of about 36 h, close to the local inertial period. The NIOs intensified mixing and modified the stratification of the upper layer, inducing uplift of nutrients and Chl a into the mixed layer from below, and leading to surface Chl a increase. The relatively shallow nutricline and thermocline in the continental shelf region before the storm were favorable for upwelling of nutrients and generation of NIOs. Advection of nutrients from enhanced runoff during and after the storm may be responsible for the larger increase of the Chl a nearshore.

  15. Ship observations and numerical simulation of the marine atmospheric boundary layer over the spring oceanic front in the northwestern South China Sea

    NASA Astrophysics Data System (ADS)

    Shi, Rui; Chen, Ju; Guo, Xinyu; Zeng, Lili; Li, Jian; Xie, Qiang; Wang, Xin; Wang, Dongxiao

    2017-04-01

    The response of the marine atmospheric boundary layer (MABL) structure to an oceanic front is analyzed using Global Positioning System (GPS) sounding data obtained during a survey in the northwestern South China Sea (NSCS) over a period of about 1 week in April 2013. The Weather Research and Forecasting (WRF) model is used to further examine the thermodynamical mechanisms of the MABL's response to the front. The WRF model successfully simulates the change in the MABL structure across the front, which agrees well with the observations. The spatially high-pass-filtered fields of sea surface temperature (SST) and 10 m neutral equivalent wind from the WRF model simulation show a tight, positive coupling between the SST and surface winds near the front. Meanwhile, the SST front works as a damping zone to reduce the enhancement of wind blowing from the warm to the cold side of the front in the lower boundary layer. Analysis of the momentum budget shows that the most active and significant term affecting horizontal momentum over the frontal zone is the adjustment of the pressure gradient. It is found that the front in the NSCS is wide enough for slowly moving air parcels to be affected by the change in underlying SST. The different thermal structure upwind and downwind of the front causes a baroclinic adjustment of the perturbation pressure from the surface to the midlayer of the MABL, which dominates the change in the wind profile across the front.

  16. Transport of terrigenous polycyclic aromatic hydrocarbons affected by the coastal upwelling in the northwestern coast of South China Sea.

    PubMed

    Ya, Miaolei; Wu, Yuling; Li, Yongyu; Wang, Xinhong

    2017-10-01

    Coastal upwelling prevails in the coast of Hainan Island, the northern South China Sea (SCS) during summer. We studied the influences of the upwelling on the horizontal and vertical transport of terrigenous polycyclic aromatic hydrocarbons (PAHs). PAHs in dissolved and suspended particulate phase of water samples were determined in the upper (depth < 1 m) and water column (depth > 10 m). PAH levels decreased sharply from inshore to offshore to open sea. The results showed that terrestrial input was the main source of coastal PAHs. Perylene, an important indicator of land plant-derived PAH, showed the significant correlation with PAHs (p < 0.005). This implied that fluvial transport was the primary pathway of terrigenous PAHs into the coast of northern SCS. Variations of the concentrations, compositions and diagnostic ratios of PAHs, accompanied the partition equilibrium in the water column, could indicate the selective degradation of PAHs by the plankton affected by upwelling. Different from the "traditional" transport pathway of PAHs in the water column (surface enrichment-depth depletion distribution), the upwelling could provide the original driver to elevate the upward diffusion of sediment entrained contaminants towards the intermediate even the upper waters. It could also enhance the outward diffusion of terrigenous PAHs accompanied by the offshore transport of the upper waters. Therefore, the transport pathway of PAHs can be summarized by the coastal upwelling rising PAHs with their subsequent transport offshore and settling in the adjacent open sea. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Wood Energy Potential in Northwestern South Carolina

    Treesearch

    James W. McMinn

    1986-01-01

    The quantity of unused wood in an Ill-county area in northwestern South Carolina was projected to be more than 16 million tons annually. Wood that is unsuitable for products other than fuel amounts to nearly 9 million tons annually.The most likely energy demand by industrial plants that are good candidates for wood fuel systems is 1.5 million tons annually.Maximum...

  18. Response of geomorphic and geological processes to insufficient and ample sediment supply along the upper continental slope in the north-western South China Sea

    NASA Astrophysics Data System (ADS)

    Chen, Hongjun; Zhan, Wenhuan; Wu, Shiguo

    2016-12-01

    We document upper slope sedimentary process and strata on the passive margin of the north-western South China Sea (SCS) using multibeam bathymetry and high-resolution seismic data. The upper slope can be divided into two segments based on geomorphology, strata, and sediment supply. (1) The east segment is characterised by deep incised canyons and gullies, and slope failure. Submarine canyons with both U- and V-shaped morphology (13-28 km long × 2-4 km wide) are oriented NNE-SSW or NNW-SSE and are approximately perpendicular to the slope. Erosion is dominant, with escarpments, slumps, and several mass transport deposits (MTDs). Shelf-margin clinoforms show strongly upward vertical aggradation with time and are strongly aggradational in style. Since 5.5 Ma, the shelf break line migrated southwards and then retreated to its present position. The segment is classified as erosion-dominated due to insufficient sediment supply. (2) The west segment has a smooth surface, gentle gradient, and a strongly progradational style, with MTDs triggered by high sedimentation rates. Shelf-margin clinoforms display a combination of progradational and aggradational stacking patterns. The shelf break line migrated southwards with time. The segment is classified as deposition-dominated, resulting from plentiful sediment supply. Depositional models have been constructed for each segment: a constant shelf break model with insufficient sediment supply in the east, and a migration shelf break model with plenty sediment supply in the west. This case study contributes to the understanding of the upper slope sedimentary process and stratigraphic style under different sediment supply conditions.

  19. Authigenic carbonates from newly discovered active cold seeps on the northwestern slope of the South China Sea: Constraints on fluid sources, formation environments, and seepage dynamics

    NASA Astrophysics Data System (ADS)

    Liang, Qianyong; Hu, Yu; Feng, Dong; Peckmann, Jörn; Chen, Linying; Yang, Shengxiong; Liang, Jinqiang; Tao, Jun; Chen, Duofu

    2017-06-01

    Authigenic carbonates recovered from two newly discovered active cold seeps on the northwestern slope of the South China Sea have been studied using petrography, mineralogy, stable carbon and oxygen isotopic, as well as trace element compositions, together with AMS 14C ages of shells of seep-dwelling bivalves to unravel fluid sources, formation conditions, and seepage dynamics. The two seeps (ROV1 and ROV2), referred to as 'Haima seeps' herein, are approximately 7 kilometers apart, and are typified by abundant carbonate rocks represented bycrusts and nodules. Aragonite and high-Mg calcite are the main carbonate minerals. Based on low δ13Ccarbonate values ranging from -43.0‰ to -27.5‰ (V-PDB) methane is apparently the predominant carbon source of seep carbonates. The corresponding δ18O values, varying from 2.5‰ to 5.8‰ (V-PDB), mostly are higher than calculated values representing precipitation in equilibrium with seawater (2.5‰ to 3.8‰), which probably reflects past destabilization of locally abundant gas hydrates. In addition, we found that carbonates with bivalve shells are generally aragonite-dominated, and bear no barium enrichment but uranium enrichments, reflecting shallow formation depths close to the seafloor. In contrast, carbonate crusts without bivalve shells and nodules contain more calcite, and are characterized by major molybdenum enrichment and different degrees of barium enrichment, agreeing with precipitation at greater depth under strictly anoxic conditions. AMS 14C ages suggest that a major episode of carbonate precipitation occurred between 6.1 ka and 5.1 ka BP at the Haima seeps, followed by a possibly subordinate episode from approximately 3.9 ka to 2.9 ka BP. The common occurrence of dead bivalves at both sites indicates that chemosynthesis-based communities flourished to a greater extent in the past, probably reflecting a decline of seepage activity in recent times. Overall, these results confirm that authigenic carbonates from

  20. Correlation slopes of GEM / CO, GEM / CO2, and GEM / CH4 and estimated mercury emissions in China, South Asia, the Indochinese Peninsula, and Central Asia derived from observations in northwestern and southwestern China

    NASA Astrophysics Data System (ADS)

    Fu, X. W.; Zhang, H.; Lin, C.-J.; Feng, X. B.; Zhou, L. X.; Fang, S. X.

    2015-01-01

    Correlation analyses between atmospheric mercury (Hg) and other trace gases are useful for identification of sources and constraining regional Hg emissions. Emissions of Hg in Asia contribute significantly to the global budget of atmospheric Hg. However, due to the lack of reliable data on the source strength, large uncertainties remain in the emission inventories of Hg in Asia. In the present study, we calculated the correlation slopes of GEM / CO, GEM / CO2, and GEM / CH4 for mainland China, South Asia, the Indochinese Peninsula, and Central Asia using the ground-based observations at three remote sites in northwestern and southwestern China, and applied these values to estimate GEM emissions in the four source regions. The geometric mean GEM / CO correlation slopes for mainland China, South Asia, the Indochinese Peninsula, and Central Asia were 7.3 ± 4.3, 7.8 ± 6.4, 7.8 ± 5.0, and 13.4 ± 9.5 pg m-3 ppb-1, respectively, and values in the same source regions were 33.3 ± 30.4, 27.4 ± 31.0, 23.5 ± 15.3, and 20.5 ± 10.0 pg m-3 ppb-1 for the GEM / CH4 correlation slopes, respectively. The geometric means of GEM / CO2 correlation slopes for mainland China, South Asia, and Central Asia were 240 ± 119, 278 ± 164, 315 ± 289 pg m-3 ppm-1, respectively. These values were the first reported correlation slopes of GEM / CO, GEM / CO2, and GEM / CH4 in four important source regions of Asia, not including the GEM / CO ratios in mainland China. The correlation slopes of GEM / CO, GEM / CO2, and GEM / CH4 in Asia were relatively higher than those observed in Europe, North America, and South Africa, which may highlight GEM emissions from non-ferrous smelting, large-scale and artisanal mercury and gold production, natural sources, and historically deposited mercury (re-emission) in Asia. Using the observed GEM / CO and GEM / CO2 slopes, and the recently reported emission inventories of CO and CO2, the annual GEM emissions in mainland China, South Asia, the Indochinese

  1. FACING SOUTH OF LANDSCAPING IN NORTHWESTERN PORTION OF PARK ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    FACING SOUTH OF LANDSCAPING IN NORTHWESTERN PORTION OF PARK - Candler Park Historic District, Roughly bounded by Moreland, Dekalb, McLendon & Harold Avenues, Matthews Street & Clifton Terrace, Atlanta, Fulton County, GA

  2. Modern dust aerosol availability in northwestern China.

    PubMed

    Wang, Xunming; Cheng, Hong; Che, Huizheng; Sun, Jimin; Lu, Huayu; Qiang, Mingrui; Hua, Ting; Zhu, Bingqi; Li, Hui; Ma, Wenyong; Lang, Lili; Jiao, Linlin; Li, Danfeng

    2017-08-18

    The sources of modern dust aerosols and their emission magnitudes are fundamental for linking dust with climate and environment. Using field sample data, wind tunnel experiments and statistical analysis, we determined the contributions of wadis, gobi (stony desert), lakebeds, riverbeds, and interdunes to modern dust aerosol availability in the three important potential dust sources including the Tarim Basin, Qaidam Basin, and Ala Shan Plateau of China. The results show that riverbeds are the dominant landscape for modern dust aerosol availabilities in the Qaidam Basin, while wadis, gobi, and interdunes are the main landscapes over the Ala Shan Plateau and Tarim Basin. The Ala Shan Plateau and Tarim Basin are potential dust sources in northwestern China, while the Qaidam Basin is not a major source of the modern dust aerosols nowadays, and it is not acting in a significant way to the Loess Plateau presently. Moreover, most of modern dust aerosol emissions from China originated from aeolian processes with low intensities rather than from major dust events.

  3. Petroleum in the Junggar basin, northwestern China

    NASA Astrophysics Data System (ADS)

    Taner, Irfan; Kamen-Kaye, Maurice; Meyerhoff, Arthur A.

    The Junggar basin occupies a large triangular area of some 130 000 km 2 in northwestern China. Situated between the Altay Shan (Altay Range) on the northeast and the Tian Shan (Tian Range) on the southwest, and between lesser ranges around the remainder of its periphery, the Junggar basin is completely intermontane. Its history as a basin began in the Permian, and continued as various uplifts and downwarps evolved. Through the Paleozoic the characteristics of the Junggar basin area were largely geosynclinal and marine. Its post-Permian development took place exclusively in continental regimes. Inhabitants of the Junggar basin have known and utilized its numerous oil and asphalt seeps and its spectacular spreads of asphalt for more than 2000 years, especially in the Karamay-Urho thrust belt near the northwestern rim. The first discovery of oil in the modern sense came at Dushanzi, one of the steeply folded anticlines of theÜrümqi foredeep near the southern rim. The first shallow oil in the Karamay-Urho thrust belt came in 1937, followed by commercial production in the Karamay field in 1955. Output continued to be modest until wells were drilled through local thrusts and reverse faults in the early 1980s. By 1985, cumulative production of the Karamay group of fields had reached 42,000,000 t (metric tonnes) (306,000,000 bbl), with a calculated minimum ultimate recovery of 280,000,000 t (2 billion bbl). Principal production comes from Permian and Triassic strata in continental facies. Apart from marine Mid and Upper Carboniferous strata, source rocks occur mainly in fine-grained lacustrine detrital beds of the Permian, the Triassic, the Jurassic and the Tertiary. Several uplifts and downwarps elsewhere in the Junggar basin remain to be drilled comprehensively. Results from such drilling may enhance the very important position that the Junggar already has attained in the hierarchy of China's onshore basins.

  4. Recent warming evidence inferred from a tree-ring-based winter-half year minimum temperature reconstruction in northwestern Yichang, South Central China, and its relation to the large-scale circulation anomalies

    NASA Astrophysics Data System (ADS)

    Cai, Qiufang; Liu, Yu; Wang, Yanchao; Ma, Yongyong; Liu, Han

    2016-12-01

    High-resolution winter temperature reconstructions in China are rare, yet vital for the comprehensive understanding of past climate change. In the present work, the first winter-half year minimum mean temperature from previous November to current April in northwestern Yichang, South Central China, was reconstructed back to 1875 based on tree-ring material. The reconstruction can explain 55 % of the variance over the calibration period during 1955-2011. The temperature maintained at comparatively low level before 1958, and an abnormal warming was seen since 1959. However, the warming trend stagnated after 2000 AD. 2001-2010 was the warmest decade not only during the instrumental period but also during the whole reconstructed period. The reconstruction indicates good spatial resemblance to other temperatures series in adjacent areas and Northern Hemisphere, yet the recent warming in this study is earlier and more prominent than that of Southeast China. This work also manifests that the winter-half year minimum temperature in study area has good agreement with summer (June-September) maximum temperature variation in Southeast China at decadal scale, except that the winter-half year warming in recent decades is more evident than summer. This reconstruction is not only useful in improving our knowledge of long-term temperature variation but also useful in predicting the tree growth dynamics in the future in the study area.

  5. A modeling study of the characteristics and mechanism of the westward coastal current during summer in the northwestern South China Sea

    NASA Astrophysics Data System (ADS)

    Ding, Yang; Bao, Xianwen; Yao, Zhigang; Zhang, Cong; Wan, Kai; Bao, Min; Li, Ruixiang; Shi, Maochong

    2017-03-01

    The characteristics and dynamical mechanism of summer-time coastal current over the North South China Sea shelf have been investigated based on a high resolution unstructuredgrid finite volume community ocean model (FVCOM). Modeldata comparison demonstrates that the model describes and explains well the coastal dynamics over the North South China Sea shelf. The coastal current on the North South China Sea shelf is greatly influenced by monsoon and the freshwater discharge of the Pearl River. Strong southwesterly wind drives the coastal current northeastward. However, under weak southwest monsoon, the coastal current west of the Pearl River estuary (PRE) advects toward the southwest, and splits into two parts when reaching east of the Qiongzhou Strait, with one branch entering the Gulf of Tonkin through the Qiongzhou Strait, transporting low salinity water into the Gulf of Tonkin, and the other part flows cyclonic and interacts with the northeastward current around southeast of Hainan Island, forming a cyclonic eddy east of the Qiongzhou Strait. A variety of model experiments focused on freshwater discharge, wind forcing, tidal rectification, and stratification are performed to study the physical mechanism of the southwestward coastal current which is usually against the summer wind. Process-oriented experiment results indicate that the southwest monsoon and freshwater discharge are important factors influencing the formation of southwestward coastal current during summer.

  6. A modeling study of the characteristics and mechanism of the westward coastal current during summer in the Northwestern South China Sea

    NASA Astrophysics Data System (ADS)

    Ding, Yang; Bao, Xianwen; Yao, Zhigang; Zhang, Cong; Wan, Kai; Bao, Min; Li, Ruixiang; Shi, Maochong

    2017-02-01

    The characteristics and dynamical mechanism of summer-time coastal current over the North South China Sea shelf have been investigated based on a high resolution unstructuredgrid finite volume community ocean model (FVCOM). Modeldata comparison demonstrates that the model describes and explains well the coastal dynamics over the North South China Sea shelf. The coastal current on the North South China Sea shelf is greatly influenced by monsoon and the freshwater discharge of the Pearl River. Strong southwesterly wind drives the coastal current northeastward. However, under weak southwest monsoon, the coastal current west of the Pearl River estuary (PRE) advects toward the southwest, and splits into two parts when reaching east of the Qiongzhou Strait, with one branch entering the Gulf of Tonkin through the Qiongzhou Strait, transporting low salinity water into the Gulf of Tonkin, and the other part flows cyclonic and interacts with the northeastward current around southeast of Hainan Island, forming a cyclonic eddy east of the Qiongzhou Strait. A variety of model experiments focused on freshwater discharge, wind forcing, tidal rectification, and stratification are performed to study the physical mechanism of the southwestward coastal current which is usually against the summer wind. Process-oriented experiment results indicate that the southwest monsoon and freshwater discharge are important factors influencing the formation of southwestward coastal current during summer.

  7. Highland macrolichen flora of Northwestern Yunnan, China.

    PubMed

    Hur, Jae-Seoun; Wang, Li-Song; Oh, Soon-Ok; Kim, Gyoung Hee; Lim, Kwang-Mi; Jung, Jae-Sung; Koh, Young Jin

    2005-06-01

    Fifty-six species in 36 genera of macrolichens are reported from the Zhongdian area, northwest Yunnan, China during the lichenological expedition for highland macrolichen survey in June, 2004. More than 60% of these species have not been reported in South Korea. All of the 182 collected specimens are deposited in the Korean Lichen Research Institute (KoLRI) at Sunchon National University in Korea, and some of them are duplicated in the lichen herbarium, Crytogamic Herbarium, Kunming Institute of Botany, Academia Sinica (KUN-L) in China. This is the first report on the macrolichen flora in the visited areas.

  8. Insights from heavy minerals and zircon U-Pb ages into the middle Miocene-Pliocene provenance evolution of the Yinggehai Basin, northwestern South China Sea

    NASA Astrophysics Data System (ADS)

    Jiang, Tao; Cao, Licheng; Xie, Xinong; Wang, Zhenfeng; Li, Xushen; Zhang, Yingzhao; Zhang, Daojun; Sun, Hui

    2015-08-01

    The well-preserved Cenozoic sedimentary record in the Yinggehai Basin, South China Sea, is suitable to explore the tectonic and climatic evolution of SE Asia. Red River, a large-scale fluvial system in this region, was previously regarded as the major sediment source for the basin. Here we combine heavy mineral analysis and detrital zircon U-Pb dating to shed new light on the middle Miocene-Pliocene provenance evolution at a basin scale. The results clearly reveal potential source areas additional to the Red River. Sediments have been delivered to the proximal areas from Hainan Island, as indicated by the high zircon content and the Yanshanian U-Pb ages in the southern segment of the Yingdong Slope. A provenance from Central Vietnam is explicitly discerned in the upper Miocene of the Central Depression, where sediments are characterized by few metamorphic heavy minerals and the U-Pb age pattern peaking at around 250 Ma and 440 Ma. Coeval large-scale relative sea-level fall and rapid exhumation along the Vietnamese margin together may have facilitated this long-distance sediment transport. Provenance of sediments from the Red River seems to change over time. Song Lo River, on the north side of the main stream, probably flowed from the NE and carried Neoproterozoic-early Paleozoic zircons to the Yinggehai Basin during the middle Miocene. Since the late Miocene, rocks along the Red River Fault Zone have become the dominant source. Subsequently, widespread metamorphic minerals in the Central Depression of the Yinggehai Basin, combined with the strong river incision and high offshore sedimentation rates, indicate an increased sediment supply from the Red River in the Pliocene.

  9. South China Sea

    USGS Publications Warehouse

    Morton, Brian; Blackmore, Graham

    2001-01-01

    The South China Sea is poorly understood in terms of its marine biota, ecology and the human impacts upon it. What is known is most often contained in reports and workshop and conference documents that are not available to the wider scientific community. The South China Sea has an area of some 3.3 million km2 and depths range from the shallowest coastal fringe to 5377 m in the Manila Trench. It is also studded with numerous islets, atolls and reefs many of which are just awash at low tide. It is largely confined within the Tropic of Cancer and, therefore, experiences a monsoonal climate being influenced by the Southwest Monsoon in summer and the Northeast Monsoon in winter. The South China Sea is a marginal sea and, therefore, largely surrounded by land. Countries that have a major influence on and claims to the sea include China, Malaysia, the Philippines and Vietnam, although Thailand, Indonesia and Taiwan have some too. The coastal fringes of the South China Sea are home to about 270 million people that have had some of the fastest developing and most vibrant economies on the globe. Consequently, anthropogenic impacts, such as over-exploitation of resources and pollution, are anticipated to be huge although, in reality, relatively little is known about them. The Indo-West Pacific biogeographic province, at the centre of which the South China Sea lies, is probably the world's most diverse shallow-water marine area. Of the three major nearshore habitat types, i.e., coral reefs, mangroves and seagrasses, 45 mangrove species out of a global of 51, most of the currently recognised 70 coral genera and 20 of 50 known seagrass species have been recorded from the South China Sea. The island groups of the South China Sea are all disputed and sovereignty is claimed over them by a number of countries. Conflicts have in recent decades arisen over them because of perceived national rights. It is perhaps because of this that so little research has been undertaken on the South

  10. South China Sea.

    PubMed

    Morton, B; Blackmore, G

    2001-12-01

    The South China Sea is poorly understood in terms of its marine biota, ecology and the human impacts upon it. What is known is most often contained in reports and workshop and conference documents that are not available to the wider scientific community. The South China Sea has an area of some 3.3 million km2 and depths range from the shallowest coastal fringe to 5377 m in the Manila Trench. It is also studded with numerous islets, atolls and reefs many of which are just awash at low tide. It is largely confined within the Tropic of Cancer and, therefore, experiences a monsoonal climate being influenced by the Southwest Monsoon in summer and the Northeast Monsoon in winter. The South China Sea is a marginal sea and, therefore, largely surrounded by land. Countries that have a major influence on and claims to the sea include China, Malaysia, the Philippines and Vietnam, although Thailand, Indonesia and Taiwan have some too. The coastal fringes of the South China Sea are home to about 270 million people that have had some of the fastest developing and most vibrant economies on the globe. Consequently, anthropogenic impacts, such as over-exploitation of resources and pollution, are anticipated to be huge although, in reality, relatively little is known about them. The Indo-West Pacific biogeographic province, at the centre of which the South China Sea lies, is probably the world's most diverse shallow-water marine area. Of three major nearshore habitat types, i.e., coral reefs, mangroves and seagrasses, 45 mangrove species out of a global total of 51, most of the currently recognised 70 coral genera and 20 of 50 known seagrass species have been recorded from the South China Sea. The island groups of the South China Sea are all disputed and sovereignty is claimed over them by a number of countries. Conflicts have in recent decades arisen over them because of perceived national rights. It is perhaps because of this that so little research has been undertaken on the

  11. The use of photovoltaics for rural electrification in northwestern China

    SciTech Connect

    Wallace, W.L.; Li Jingming; Gao Shangbin

    1998-09-01

    The use of renewable energy technologies in China is becoming increasingly important to meet the needs of a large rural population. Solar and wind renewable resources in particular are available in regions of China that at present have no access to conventional grid power. Two regions in China that have an acute lack of electricity are a large region in northern and western China and the coastal island region of China. These regions have attracted the attention of the Chinese government in terms of increasing the quality of life and standard of living conditions of the rural population. These regions have also attracted the attention of domestic Chinese companies and of international companies, governments, and multilateral development organizations as a potential market for renewable energy rural electrification systems. This paper focuses on the bilateral cooperation between the US Department of Energy and China in providing assistance for the use of renewable technologies for rural electrification in northwestern China.

  12. S-wave velocity structure and tectonic implications of the northwestern sub-basin and Macclesfield of the South China Sea

    NASA Astrophysics Data System (ADS)

    Wei, Xiaodong; Ruan, Aiguo; Li, Jiabiao; Niu, Xiongwei; Wu, Zhenli; Ding, Weiwei

    2016-10-01

    Based on the optimum P-wave model, the S-wave velocity structure of a wide angle seismic profile (OBS2006-1), across the northwestern sub-basin (NWSB) and the Macclesfield, is simulated by a 2-D ray-tracing method. The results indicate the S-wave velocities in the upper and lower crust of the NWSB are 3.2-3.6 km/s and 3.6-4.0 km/s, with Vp/Vs ratios of 1.82-1.88 and 1.74-1.82, respectively, which reflect typical oceanic crust characteristics. The S-wave velocity in the upper crust of the NWSB is a little higher in the NNW segment than that in the SSE segment, while the lateral variation of Vp/Vs ratio is in the opposite. We suggest that the NWSB might have experienced asymmetrical magma flows during sea floor spreading, which may have blurred the magnetic anomaly lineation. The comparison of S-wave velocities along the northern margin of the SCS shows that the west section is different from the east section, and the northwestern margin has a non-volcanic crust structure. The S-wave structures and P-wave velocity models along the northern margin, Macclesfield and Reed Bank show that the Macclesfield might have a conjugate relationship with the Reed Bank.

  13. S-wave velocity structure and tectonic implications of the northwestern sub-basin and Macclesfield of the South China Sea

    NASA Astrophysics Data System (ADS)

    Wei, Xiaodong; Ruan, Aiguo; Li, Jiabiao; Niu, Xiongwei; Wu, Zhenli; Ding, Weiwei

    2017-06-01

    Based on the optimum P-wave model, the S-wave velocity structure of a wide angle seismic profile (OBS2006-1), across the northwestern sub-basin (NWSB) and the Macclesfield, is simulated by a 2-D ray-tracing method. The results indicate the S-wave velocities in the upper and lower crust of the NWSB are 3.2-3.6 km/s and 3.6-4.0 km/s, with Vp/ Vs ratios of 1.82-1.88 and 1.74-1.82, respectively, which reflect typical oceanic crust characteristics. The S-wave velocity in the upper crust of the NWSB is a little higher in the NNW segment than that in the SSE segment, while the lateral variation of Vp/ Vs ratio is in the opposite. We suggest that the NWSB might have experienced asymmetrical magma flows during sea floor spreading, which may have blurred the magnetic anomaly lineation. The comparison of S-wave velocities along the northern margin of the SCS shows that the west section is different from the east section, and the northwestern margin has a non-volcanic crust structure. The S-wave structures and P-wave velocity models along the northern margin, Macclesfield and Reed Bank show that the Macclesfield might have a conjugate relationship with the Reed Bank.

  14. Climate Change and Neotectonic History of Northwestern China

    NASA Technical Reports Server (NTRS)

    Farr, Tom G.; Chadwick, Oliver; Evans, Diane; Gillespie, Alan; Peltzer, Gilles; Tapponnier, Paul

    1996-01-01

    The progress, results and future plans for the following objectives are presented: (1) To compare the types, rates, and magnitudes of surficial modification processes that have operated in Northwest China and the Southwestern U.S.; (2) To quantify and understand the basis of the remote sensing signatures of these processes to allow extrapolation from field sites to regional maps and to allow comparisons between widely separated arid regions; (3) To use the resulting chronologies to help define the temporal and spatial distribution of continental climate changes; and (4) Determine the ages of movements on some of the active faults in Northwestern China.

  15. Climate Change and Neotectonic History of Northwestern China

    NASA Technical Reports Server (NTRS)

    Farr, Tom G.; Chadwick, Oliver; Evans, Diane; Gillespie, Alan; Peltzer, Gilles; Tapponnier, Paul

    1996-01-01

    The progress, results and future plans for the following objectives are presented: (1) To compare the types, rates, and magnitudes of surficial modification processes that have operated in Northwest China and the Southwestern U.S.; (2) To quantify and understand the basis of the remote sensing signatures of these processes to allow extrapolation from field sites to regional maps and to allow comparisons between widely separated arid regions; (3) To use the resulting chronologies to help define the temporal and spatial distribution of continental climate changes; and (4) Determine the ages of movements on some of the active faults in Northwestern China.

  16. Deformation of Northwestern South America from GPS Geodesy

    NASA Astrophysics Data System (ADS)

    Mora-Paez, H.; La Femina, P. C.; Mothes, P. A.; Ruiz, A. G.; Fernandes, R. M.

    2013-12-01

    The North Andes block (NAB) is a hypothesized tectonic block that migrates (escapes) north-northeast relative to a stable South American reference frame. The motion of this block is thought-to-be derived by the collision of the Carnegie Ridge in southern Ecuador and/or by oblique convergence and high degrees of interplate coupling north of the ridge (i.e., strain partitioning). At the latitude of Ecuador, the NAB is defined by transpressional deformation accommodating east-northeastward motion along its boundary with South America. In southern to central Colombia, the NAB is dissected by several mapped and prominent regional shear zones. At these latitudes the NAB may be bound to the west by the Choco block and the transpressional Atrato-Uraba fault system and to the east by the Guayaquil-Algeciras fault system. And in northern Colombia the Caribbean - South America plate boundary is defined by the NAB and proposed Maracaibo and Guajira blocks. We investigate the deformation of northwestern South America, including the kinematics of NAB utilizing a new velocity field based on continuous GPS and existing episodic GPS data in Ecuador, Colombia, Venezuela and Panama. We reference these new velocities to a newly estimated Euler vector for the South America plate based on inversion of cGPS data from stations east of the Andes. The new velocity field and published earthquake slip vectors are inverted to solve for the Euler vectors of the NAB, Choco, Panama, Maracaibo and Guajira blocks and interseismic elastic strain accumulation (interseismic coupling) on block-bounding faults using a block modeling approach. We test a suite of block models to investigate the tectonic nature of the NAB along strike and the style of faulting in the upper plate accommodating block motion. Through the estimation of elastic strain accumulation on all block-bounding faults, we improve the understanding of interseismic coupling along a convergent margin capable of producing M>8 earthquakes

  17. Metamorphic evolution of the northwestern Ogcheon metamorphic belt, South Korea

    NASA Astrophysics Data System (ADS)

    Min, Kyoungwon; Cho, Moonsup

    1998-05-01

    The Ogcheon metamorphic belt (OMB) comprises Late Proterozoic to Paleozoic metasedimentary and metavolcanic sequences which are intruded by Mesozoic granitoid plutons. To delineate the metamorphic evolution of the OMB, we have investigated mineral parageneses, metamorphic reactions and P-T conditions of pelitic and mafic schists in the Chungju area, northwestern part of the OMB. The regional metamorphic grade increases north-westward from biotite to garnet zones, although low-pressure assemblages have developed in contact aureoles around Jurassic granites. Garnet crystals show chemical zoning, typical for prograde metamorphism, with decreasing Mn, and increasing Fe and Mg from core to rim. Compositions of amphiboles constituting the common assemblage in the mafic schist are consistent with those of biotite- and garnet-zones documented in the medium-pressure metabasites. P-T conditions of the garnet zone, estimated from garnet-biotite, garnet-chlorite and amphibole-plagioclase geothermometers together with garnet-plagioclase-biotite-muscovite/quartz geobarometers, are in the range of 5-8 kbar and 520-590°C. Retrograde P-T path based on fluid inclusion studies suggests that the exhumation of the OMB has passed through the P-T range of 1-3 kbar and 350-500°C, following the isochore curves of the CO 2 inclusions. In conjunction with structural and geochronologic data, we conclude that the OMB has experienced a polycyclic P-T evolution characterized by (1) crustal thickening during the Middle Paleozoic time and (2) regional retrograde metamorphism in the Triassic. Our result further suggests that the Triassic collision belt in east-central China does not pass through the OMB.

  18. Late paleozoic tectonic amalgamation of northwestern China. Sedimentary record of the northern Tarim, northwestern Turpan, and southern Junggar basins

    SciTech Connect

    Carroll, A.R.; Graham, S.A.; Hendrix, M.S.; Ying, D.; Zhou, D.

    1995-05-01

    This study focuses on areas adjacent to the Tian Shan (shan is Chinese for mountains) in Xinjiang Uygur Autonomous Region, northwestern China, and provides new field data on Carboniferous and Permian outcrop exposures of sedimentary rocks of the southern Junggar, northwestern Turpan, and northern Tarim basins that bear directly on the history of late Paleozoic tectonic amalgamation. We present here a multifaceted sedimentary basin analysis, including sedimentary facies, paleocurrent, and sandstone provenance analyses, and reconstructions of late Paleozoic basin subsidence. These data provide a unique record not only of the basins themselves, but also of the evolution of the adjacent orogenic belts. This study is based on fieldwork during the summers of 1987, 1988, 1991, and 1992 by workers from Stanford University, the Chinese Academy of Geological Sciences, and the Xinjiang Bureau of Geology and Mineral Resources. Although reconnaissance in nature, the data presented here provide a basis for evaluating alternative hypotheses for the evolution of northwestern China and provide a starting point for more comprehensive future studies. 72 refs., 18 figs., 1 tab.

  19. South China Sea kinematics

    NASA Astrophysics Data System (ADS)

    Sibuet, J. C.; Gao, J.; Zhao, M.; Wu, J.; Ding, W.; Yeh, Y. C.; Lee, C. S.

    2016-12-01

    Magnetic modeling shows that the age of the youngest South China Sea (SCS) oceanic crust is controversial (e.g. 15.5 Ma (Briais et al., JGR 1993) and 20.5 Ma (Barckhausen et al., MPG 2014)). Recently, Sibuet et al. (Tectonophysics 2016) pointed out that post-spreading magmatic activity ( 8-13 Ma) largely masks the spreading fabric, in particular near the previously identified E-W portion of the extinct ridge axis of the East sub-basin. Their compilation of available swath bathymetric data shows that, if post-spreading volcanics hide the seafloor spreading magnetic fabric mostly along and near the extinct spreading axis, the whole SCS is globally characterized by rift directions following three directions: N055°in the youngest portion of the SCS, N065° and N085° in the oldest portions of the SCS, suggesting the extinct ridge axis is N055° trending instead of E-W. We present an updated version of the whole SCS structural sketch based on previously published swath bathymetric trends and new detailed magnetic lineations trends compiled from an extremely dense set of magnetic data. The new structural sketch shows: - The distribution of conjugate kinematic domains, - The early opening of the NW and East sub-basins, before a jump of the rift axis, - A second ridge jump in the East basin, - The different expressions of the post-spreading magmatism in the East and SW sub-basins. In the East sub-basin, crustal magmatic intrusions led to the formation of extrusive basalts associated with the presence of numerous volcanoes (Wang et al., Geological Journal 2016). In the SW sub-basin, crustal magmatic intrusions deformed and uplifted the already formed oceanic crust and oldest overlying sediments, resulting in the formation of a double post-spreading ridge belt previously identified as the shoulders of the extinct spreading rift axis. This preliminary work will be used to identify magnetic lineations not polluted by the post-spreading magmatism. The unfolded Manila trench

  20. Internal Waves, South China Sea

    NASA Image and Video Library

    1983-06-24

    STS007-05-245 (18-24 June 1983) --- A rare view of internal waves in the South China Sea. Several different series of internal waves are represented in the 70mm frame, exposed with a handheld camera by members of the STS-7 astronaut crew aboard the Earth-orbiting Challenger. The land area visible in the lower left is part of the large island of Hainan, China.

  1. Migrant Programs in the Northwestern States -- Idaho, Montana, Nebraska, North Dakota, South Dakota, Oregon, Washington, Wyoming.

    ERIC Educational Resources Information Center

    National Migrant Information Clearinghouse, Austin, TX. Juarez-Lincoln Center.

    Part of the "Comprehensive National Survey of Migrant Programs" series, this directory lists services and resources available to migrant and seasonal farmworkers during their stay in the Northwestern states of Idaho, Montana, Nebraska, North Dakota, South Dakota, Oregon, Washington, and Wyoming. Prepared for use by agencies working with…

  2. Migrant Programs in the Northwestern States -- Idaho, Montana, Nebraska, North Dakota, South Dakota, Oregon, Washington, Wyoming.

    ERIC Educational Resources Information Center

    National Migrant Information Clearinghouse, Austin, TX. Juarez-Lincoln Center.

    Part of the "Comprehensive National Survey of Migrant Programs" series, this directory lists services and resources available to migrant and seasonal farmworkers during their stay in the Northwestern states of Idaho, Montana, Nebraska, North Dakota, South Dakota, Oregon, Washington, and Wyoming. Prepared for use by agencies working with…

  3. Chloroplast phylogeography of Helianthemum songaricum (Cistaceae) from northwestern China: implications for preservation of genetic diversity

    Treesearch

    Zhihao Su; Mingli Zhang; Stewart C. Sanderson

    2011-01-01

    Two chloroplast intergenic spacers (trnD-trnT and rps16-trnK) were used to study the phylogeographical structure of Helianthemum songaricum in northwestern China, with 12 haplotypes detected. Phylogenetic analysis showed that H. songaricum comprised two lineages, one distributed in the Yili Valley and the other in the western Ordos Plateau. Nested clade phylogeographic...

  4. Education, Employment and Empowerment: The Case of a Young Woman in Northwestern China

    ERIC Educational Resources Information Center

    Maslak, Mary Ann

    2011-01-01

    As a marginalized region of the world, the rural Gansu Province of northwestern China provides an informative canvas on which to examine and understand the ways in which education contributes to the lives of local Muslim women and supports their goals for work. Specifically, this article highlights the role education plays in the life of one young…

  5. Education, Employment and Empowerment: The Case of a Young Woman in Northwestern China

    ERIC Educational Resources Information Center

    Maslak, Mary Ann

    2011-01-01

    As a marginalized region of the world, the rural Gansu Province of northwestern China provides an informative canvas on which to examine and understand the ways in which education contributes to the lives of local Muslim women and supports their goals for work. Specifically, this article highlights the role education plays in the life of one young…

  6. Canopy storage capacity of xerophytic shrubs in Northwestern China

    NASA Astrophysics Data System (ADS)

    Wang, Xin-ping; Zhang, Ya-feng; Hu, Rui; Pan, Yan-xia; Berndtsson, Ronny

    2012-08-01

    SummaryThe capacity of shrub canopy water storage is a key factor in controlling the rainfall interception. Thus, it affects a variety of hydrological processes in water-limited arid desert ecosystems. Vast areas of revegetated desert ecosystems in Northwestern China are occupied by shrub and dwarf shrub communities. Yet, data are still scarce regarding their rainwater storage capacity. In this study, simulated rainfall tests were conducted in controlled conditions for three dominant xerophytic shrub types in the arid Tengger Desert. Eight rainfall intensities varying from 1.15 to 11.53 mm h-1 were used to determine the canopy water storage capacity. The simulated rainfall intensities were selected according to the long-term rainfall records in the study area. The results indicate that canopy storage capacity (expressed in water storage per leaf area, canopy projection area, biomass, and volume of shrub respectively) increased exponentially with increase in rainfall intensity for the selected shrubs. Linear relationships were found between canopy storage capacity and leaf area (LA) or leaf area index (LAI), although there was a striking difference in correlation between storage capacity and LA or LAI of Artemisia ordosica compared to Caragana korshinskii and Hedysarum scoparium. This is a result of differences in biometric characteristics, especially canopy morphology between the shrub species. Pearson correlation coefficient indicated that LA and dry biomass are better predictors as compared to canopy projection area and volume of samples for precise estimation of canopy water storage capacity. In terms of unit leaf area, mean storage capacity was 0.39 mm (range of 0.24-0.53 mm), 0.43 mm (range of 0.28-0.60 mm), and 0.61 mm (range of 0.29-0.89 mm) for C. korshinskii, H. scoparium, and A. ordosica, respectively. Correspondingly, divided per unit dry biomass, mean storage capacity was 0.51 g g-1 (range of 0.30-0.70 g g-1), 0.41 g g-1 (range of 0.26-0.57 g g-1), and

  7. Mid-Late Miocene vegetation and environments in Southeast China: Insights from a marine palynological record in northwestern Taiwan

    NASA Astrophysics Data System (ADS)

    Hao, Xiu-dong; Weng, Chengyu; Huang, Chi-Yue; Ouyang, Xu-hong

    2017-05-01

    Taiwan Island represents the exposed accretionary prism developed by eastward subduction of South China Sea (SCS) oceanic lithosphere beneath the Philippine Sea Plate since the middle Miocene. There are many well-documented data about the biostratigraphic correlation, except for palynological studies. Here, we present a new palynological record of mid-Late Miocene deposits from the Chuhuangkeng section, Miaoli, northwestern Taiwan, which reveals a vegetation and paleoelevation reconstruction in Southeast China, during the Middle to Late Miocene, corresponding to the time interval of about 14.5-5.5 Ma. Most samples yielded well-preserved palynomorphs, and the palynological results suggest that the dominant vegetation was the mixed coniferous-broadleaved forests in the Coastal Mountains of Southeast China (CMSC) during the Mid-Late Miocene. Moreover, based on large amounts of Tsuga and Picea pollen, we hypothesized that a subalpine conifer forest then flourished in the CMSC, and the estimated maximum paleoelevation might be up to ∼3000 m above sea level (a.s.l.) during the Mid-Late Miocene, being 1000-1500 m higher than today. These findings offer a new perspective to comprehend the paleotopographic evolution of China and the source area of Taiwan's spruce forests. Additionally, the high abundance of Pinus, Tsuga, Picea pollen and fern spores also suggests an enhancement of the EASM during the Mid-Late Miocene.

  8. Observations of flow variability through the Kerama Gap between the East China Sea and the Northwestern Pacific

    NASA Astrophysics Data System (ADS)

    Na, Hanna; Wimbush, Mark; Park, Jae-Hun; Nakamura, Hirohiko; Nishina, Ayako

    2014-02-01

    The Kerama Gap, near the middle of the Ryukyu Island chain, is the deepest channel with a sill depth of 1050 m connecting the East China Sea (ECS) to the Northwestern Pacific. We measured the flow through the Kerama Gap from June 2009 to June 2011. The 2 year mean transport, 2.0 ± 0.7 Sv, is into the ECS from the Northwestern Pacific; it contributes about 11% of the mean Kuroshio transport in the ECS at the PN line. Subtidal standard deviation of the transport through the Kerama Gap is 3.2 Sv, comparable to that of the PN-line Kuroshio transport (4.0 Sv), suggesting a significant effect of Kerama Gap transport on temporal variability of the Kuroshio transport in the ECS. Comparison with time series of satellite-measured sea surface height maps reveals that temporal variability of the Kerama Gap transport is related to the arrival of mesoscale eddies from the east: high (low) transport into the ECS is associated with the presence of a cyclonic (anticyclonic) eddy south of the Kerama Gap.

  9. Long-term regional precipitation disparity in northwestern China and its driving forces

    NASA Astrophysics Data System (ADS)

    Lee, H. F.; Pei, Q.; Zhang, D. D.; Choi, K. P. K.

    2014-08-01

    Subject to the unique physical setting of northwestern China (NW China), precipitation in the region is characterized by salient regional differences. Yet, the long-term regional precipitation disparity in NW China still remains insufficiently-explored. In the present study, we base on historical documentation to reconstruct the precipitation indices of two macro regions in NW China between AD580-1979 to address the following issues: (1) determine the multi-decadal to centennial regional precipitation disparity in NW China, a topic which has not been systematically examined in previous paleo-climate/paleo-environment studies; and (2) find the major driving forces behind it. Wavelet analysis, which is ideal for analyzing non-stationary systems, is applied. Our results show that there is significant regional discrepancy of precipitation change in NW China over extended period. Although there is significant association between the regional precipitation disparity in NW China and various modes of atmospheric circulation, the association is characterized by a regime shift during the transition from the Medieval Warm Period to the Little Ice Age. Most importantly, the low-frequency cycle of the El Niño-Southern Oscillation is found to be the most prominent pacemaker of regional precipitation disparity in NW China at the multi-decadal to centennial timescales. Our findings help to demonstrate which atmospheric circulation is primarily responsible for the long-term regional precipitation disparity in NW China, which may have important implications for water resource management in NW China in the near future.

  10. The basement of the Eastern Cordillera, Colombia: An allochthonous terrane in northwestern South America

    NASA Astrophysics Data System (ADS)

    Forero Suarez, A.

    The fault system of the Borde Llanero of Colombia represents the limit between two early Paleozoic geologic provinces: the Guiana Shield (Gondwana) to the east, and an allochthonous terrane — formerly a piece of the North American continent — to the west. The Baudó Range, the Western Cordillera, and the western flank of the Central Cordillera are the result of post-Jurassic accretion. In contrast the pre-Emsian metamorphic rocks of the eastern flank of the Central Cordillera, of the Eastern Cordillera of Colombia, and of the Mérida Andes correspond to an allochthonous terrane that was accreted to the north-western continental border of South America during the collision between North America and Gondwana in Silurian-Early Devonian times. Geochronologic and petrographic data indicate the presence of the Grenvillian granulite belt, represented by the Garzón-Sierra Nevada de Santa Marta belt. This belt is separated from the Guiana Shield by a magmatic tract which is parallel to the Borde Llanero of Venezuela and Colombia. The late Paleozoic regional metamorphism in the Northern Andes of Colombia occurred during Late Silurian-Early Devonian times. Since the late Emsian, a sedimentary cycle was initiated on this allochthonous basement. The faunal records of northwestern South America and the North American continent are indistinguishable for that time. This similarity clearly shows that both northwestern South America and the North American regions of the Appalachians and New Mexico belong to the same paleobiogeographic province. The faunal communication in this case supports the idea of the immediate neighborhood of the two continents.

  11. Malaria in south-western and north-western Nigerian communities

    PubMed Central

    Archibald, H. Munro

    1956-01-01

    An attempt is made to describe the comparative epidemiology of malaria in representative communities of south-western and north-western Nigeria. The climates of the two areas are contrasted and their influence on the seasonal densities and infectivities of the local vectors, Anopheles gambiae and A. funestus, is shown. Malaria occurs in holoendemic proportions in both areas and its effect on local mortality and morbidity is examined, with special reference to children in the pre-school age-groups. PMID:13404444

  12. Tectonic analysis of northwestern South America from integrated satellite, airborne and surface potential field anomalies

    NASA Astrophysics Data System (ADS)

    Hernandez, Orlando

    Northwestern South America is one of the most populated regions of the Americas with more than 80 million people concentrated along the Andes Mountains. This region includes a complex and dangerous mosaic of tectonic plates that have produced devastating earthquakes, tsunamis, volcanic eruptions and landslides in the last decades. The region's economic development has also seriously suffered because the region is poorly explored for natural resources. To more effectively assess the tectonic hazards and mineral and energy resources of this region, we must improve our understanding of the tectonic setting that produced them. This research develops improved tectonic models for northwestern South America from available satellite, airborne and surface gravity and magnetic data integrated with global digital topography, seismic, and GPS plate velocity data. Reliable crustal thickness estimates that help constrain tectonic stress/strain conditions were obtained by inverse modeling of the magnetic anomalies and terrain compensated gravity anomalies. Correlated positive Terrain Gravity Effects (TGE) and Free Air Gravity Anomalies (FAGA) suggest that the crust - mantle interface under the northwestern Andes is closer to the surface than expected, indicating that these mountains are not iso-statically compensated. Correlated negative FAGA anomalies observed along western South America and the Greater and Lesser Antilles islands are associated with iso-statically disturbed mantle displaced by subducting oceanic plates. Subtracting TGE from the terrain-correlated FAGA (TCFAGA) yield compensated terrain gravity effect (CTGE) anomalies that characterize the Andes Mountains with deep roots of low density crust displacing denser underlying mantle and thickening the local crust. FAGA and TGE correlate at all levels of compensation, but the correlations are especially strong where the compensation is less than 100%. Correlated first vertical derivative FAGA (FVD(FAGA)) and

  13. Crustal and uppermost mantle velocity structure beneath northwestern China from seismic ambient noise tomography

    NASA Astrophysics Data System (ADS)

    Li, Hongyi; Li, S.; Song, X. D.; Gong, M.; Li, X.; Jia, J.

    2012-01-01

    In this paper, we conduct ambient noise seismic tomography of northwestern China and adjacent regions. The data include 9 months (2009 January to 2009 September) three-component continuous data recorded at 146 seismic stations of newly upgraded China Provincial Digital Seismic Networks and regional Kyrgyzstan and Kazakhstan networks. Empirical Rayleigh and Love wave Green's functions are obtained from interstation cross-correlations. Group velocity dispersion curves for both Rayleigh and Love waves between 7 and 50 s periods were measured for each interstation path by applying the multiple-filter analysis method with phase-matched processing. The group velocity maps show clear lateral variations which correlate well with major geological structures and tectonic units in the study region. Shear wave velocity structures are inverted from Rayleigh wave and love wave dispersion maps. The results show that the Tibetan Plateau has a very thick crust with a low-velocity zone in its mid-lower crust. Along the northern margin of the plateau where a steep topographic gradient is present, the low-velocity zone does not extend to the Tarim basin which may indicate that crustal materials beneath the Tarim basin are colder and stronger than beneath the plateau, therefore inhibit the extension of mid-lower crustal flow and deformation of the Tibetan Plateau, resulting in very sharp topography contrasts. In the northeastern margin with a gentle topographic gradient toward the Ordos platform, the low-velocity zone diminishes around the eastern KunLun fault. Meanwhile, our results reveal obvious lateral velocity changes in the crust beneath the Tarim basin. In the upper crust, the Manjaer depression in the eastern Tarim basin is featured with very low velocities and the Bachu uplift in the western Tarim basin with high velocities; in the mid-lower crust, the northern Tarim basin in general displays lower velocities than the southern part along latitude ˜40° N with an east

  14. Subduction Dynamics in Northwestern South America from SKS and Local S-wave Splitting Measurements

    NASA Astrophysics Data System (ADS)

    Idarraga Garcia, J.; Kendall, J. M.; Vargas Jiménez, C. A.

    2015-12-01

    In order to investigate subduction dynamics between the South America continent and the oceanic Nazca and Caribbean plates, we have obtained 257 high-quality splitting measurements from teleseismic SKS phases and 85 splitting results from slab-related local Sphases arriving at 38 seismic stations in northwestern South America. We used data primarily from the Colombia National Seismological Network. Our first observation is that delay times obtained from SKS splitting (mean value of 1.15 s) are consistently greater than those from the local S splitting (mean value of 0.31 s). This implies that most of the SKSsplitting is due to upper mantle anisotropy beneath or within the subducting slabs. In contrast, the polarizations of local S-waves are consistently aligned with crustal-scale fault systems, which implies that the anisotropy above the slabs is dominated by tectonic features in the overriding crust or lithosphere, and that the mantle wedge is not contributing significantly to the measured splitting. We identify a clear change in SKS fast directions at the trace of the so-called Caldas Tear (~5°N), which represents a boundary in the style of subduction. To the north of Caldas Tear fast directions are consistently parallel to the direction of convergence of the Caribbean plate and Panama arc with South America. Our results support the idea of Caribbean subduction beneath northwestern Colombia, a hotly debated topic in recent years. Fast directions south of the Caldas tear are subparallel to the direction of Nazca-South America convergence. Entrained mantle flow and deformation beneath the subducting Nazca and Caribbean plates are the main cause of the measured SKS splitting. Further inland, the SKS splitting is consistent with mantle flow parallel to the trend of the Eastern Cordillera. We speculate that a change in slab dip may lead to a change in mantle flow and may be responsible for the intermediate-depth nests of seismicity observed beneath Eastern Cordillera.

  15. Analogous Study of the Linguistic Knowledge between Monolingual and Bilingual Students in the Minority Region of Northwestern China

    ERIC Educational Resources Information Center

    He, Hao

    2008-01-01

    Minority students' English learning is a special and an indispensable component of English education system in China. This article studies students' linguistic knowledge that live in Northwestern China--Gan Nan Autonomy State of Gan Su Province with majority population of Tibetan, mixed with Chinese and some Muslim. An analogous analysis is…

  16. The choco block in the northwestern corner of South America: Structural, tectonostratigraphic, and paleogeographic implications

    NASA Astrophysics Data System (ADS)

    Duque-Caro, H.

    The Choco Block, located in the northwestern corner of South America, comprises the isthmus of Panama east of the Canal Zone and northwestern Colombia, including the westernmost flanks of the Cordillera Occidental above latitude 4°N. Three major structural and lithogenetic elements compose this terrain: the Dabeiba and Baudo Arches, the Atrato-Chucunaque Basins, and the Istmina Deformed Zone. The Dabeiba and Baudo Arches outline the external boundaries of the Choco Block and display similar characteristics: (a) mostly positive gravity anomalies and association of igneous bodies of oceanic origin with sedimentary suites, and (b) occurence of Upper Cretaceous to Miocene pelagic and hemipelagic and terrigenous strata in blocks of different ages and environments associated with mafic igneous rocks. The Dabeiba Arch exhibits a melange fabric, particularly at its eastern margin, in which disrupted strata and inclusions of Upper Cretaceous-Paleocene, Eocene-Oligocene, and Miocene exotic blocks are dispersed in a sheared pelitic matrix of middle Miocene age. The Atrato-Chucunaque Basins contain sedimentary fill exceeding 10 km in thickness. Two distinctive stratigraphic sequences comprise: (1) an outcropping and apparently continuous Oligocene to middle Miocene sequence composed mostly of pelagic and hemipelagic strata, overlain by hemipelagic and terrigenous strata of latest Middle Miocene to Pliocene age, and (2) an underlying middle Miocene and older sequence, composed mostly of turbidities, which has been recognized only in subsurface sections. An evaluation and synthesis of the structural and lithogenetic information of the Choco Block indicate the following conclusions. The Choco Block is an exotic terrane with no lithogenetic affinity with South America, accreted onto the northwestern flanks of the Cordillera Occidental during the middle Miocene. The occurence of exotic upper Paleocene planktic foraminiferal assemblages in the Dabeiba Arch suggests an origin for

  17. South China connected to north India in Gondwana: sedimentary basin and detrital provenance analyses

    NASA Astrophysics Data System (ADS)

    Yao, W.; Li, Z. X.; Li, W. X.; Li, X. H.; Yang, J. H.

    2015-12-01

    The paleoposition of South China during the Ediacaran-Silurian is important for understanding the assembly of Gondwana. We report here the tectonostratigraphic evolution of the Ediacaran-Silurian Nanhua foreland basin in South China, and discuss South China's connection with Gondwana and potential tectonic triggers for both the Wuyi-Yunkai orogeny in South China and the Bhimphedian orogeny in north India. The Nanhua basin was involved in a three-stage evolution, which are: Stage 1 (the Ediacaran-Cambrian) recording the start of tectonic subsidence with turbiditic marine clastic deposition, fed by exotic orogens outboard South China; Stage 2 (the Ordovician to earliest-Silurian) featured by migrating depocentres with dominant shallow marine to deltaic clastic deposition, fed by the local Wuyi-Yunkai orogen; and Stage 3 (the Silurian) showing the arrival of depocentre in the Yangtze Block during the waning stage of the Wuyi-Yunkai orogeny with deltaic deposition in the remanent foreland basin. Detrital zircon analyses of the Ediacaran-Silurian sandstones across the Nanhua basin reveal a prominent age population of 1100-900 Ma (with a peak age at ~980 Ma) and moderate populations of Archean-Paleozoic ages, grossly matching that of crystalline and sedimentary rocks in northern India. Zircon isotopes of the Stage 1 samples suggest three Precambrian episodes of juvenile crustal growth at 3.0 Ga, 2.5 Ga and 1.0 Ga, and a major crustal reworking at 580-500 Ma for the source areas, which are constraint to be northwestern India and its surrounding orogens. Together with other evidence, we propose that South China likely collided with northwestern India during the Gondwana assembly, generated the Bhimphedian orogeny in north India and formed two foreland basins on both the north India and South China sides. Far-field stress of the collision triggered the Ordovician-Silurian Wuyi-Yunkai orogeny in South China. The Stage 2-3 samples in the Nanhua basin of South China were shed

  18. Lithospheric thickness estimation beneath Northwestern South America from an S-wave receiver function analysis

    NASA Astrophysics Data System (ADS)

    Blanco, J. Faustino; Vargas, Carlos A.; Monsalve, Gaspar

    2017-04-01

    We make use of the S-to-P receiver function technique beneath Colombia and neighboring regions to make a first-order approximation of the depth of the Lithosphere-Asthenosphere Boundary (LAB) and, therefore, of lithospheric thickness. A deconvolution technique was used to calculate the receiver functions, and after a moveout correction and a time-depth conversion, LAB depths for different tectonic regions of northwestern South America were obtained. Results are typically between 65 and 110 km, consistent with previous estimates around the world and other regions in South America. Lithospheric thickness beneath an oceanic island in the Caribbean is ˜80 km, whereas for the Ecuador-Colombia Trench it is ˜65 km, and around 100 km for the Panama Arc. The transition to the continent is associated with an increase in LAB depth, where it can reach ˜110 km, with no significant differences among terranes and/or tectonic blocks.

  19. OMI-measured increasing SO2 emissions due to energy industry expansion and relocation in northwestern China

    NASA Astrophysics Data System (ADS)

    Ling, Zaili; Huang, Tao; Zhao, Yuan; Li, Jixiang; Zhang, Xiaodong; Wang, Jinxiang; Lian, Lulu; Mao, Xiaoxuan; Gao, Hong; Ma, Jianmin

    2017-07-01

    The rapid growth of economy makes China the largest energy consumer and sulfur dioxide (SO2) emitter in the world. In this study, we estimated the trends and step changes in the planetary boundary layer (PBL) vertical column density (VCD) of SO2 from 2005 to 2015 over China measured by the Ozone Monitoring Instrument (OMI). We show that these trends and step change years coincide with the effective date and period of the national strategy for energy development and relocation in northwestern China and the regulations in the reduction of SO2 emissions. Under the national regulations for the reduction of SO2 emissions in eastern and southern China, SO2 VCD in the Pearl River Delta (PRD) of southern China exhibited the largest decline during 2005-2015 at a rate of -7 % yr-1, followed by the North China Plain (NCP) (-6.7 % yr-1), Sichuan Basin (-6.3 % yr-1), and Yangtze River Delta (YRD) (-6 % yr-1). The Mann-Kendall (MK) test reveals the step change points of declining SO2 VCD in 2009 for the PRD and 2012-2013 for eastern China responding to the implementation of SO2 control regulation in these regions. In contrast, the MK test and regression analysis also revealed increasing trends of SO2 VCD in northwestern China, particularly for several hot spots featured by growing SO2 VCD in those large-scale energy industry bases in northwestern China. The enhanced SO2 VCD is potentially attributable to increasing SO2 emissions due to the development of large-scale energy industry bases in energy-abundant northwestern China under the national strategy for the energy safety of China in the 21st century. We show that these large-scale energy industry bases could overwhelm the trends and changes in provincial total SO2 emissions in northwestern China and contribute increasingly to the national total SO2 emissions in China. Given that northwestern China is more ecologically fragile and uniquely susceptible to atmospheric pollution than the rest of China, increasing SO2

  20. The South China Sea Deep: Introduction

    NASA Astrophysics Data System (ADS)

    Wang, Pinxian; Li, Qianyu; Dai, Minhan

    2015-12-01

    The South China Sea (SCS) has increasingly become a global focus in ocean research and hydrocarbon explorations. Over the last two decades, at least 17 international cruises including two ODP/IODP expeditions were conducted in the SCS, and more than 2000 exploratory wells were drilled (Wang et al., 2014a). While its sedimentary basins on the continental shelf and slope are explored for offshore resources, the deep basin below 3500 m in depth that overlies the basaltic oceanic crust preserves the key to understanding their formation and development. In order to better understand the life history and functional system of the marginal sea, a major research program "Deep Sea Processes and Evolution of the South China Sea", or "The South China Sea Deep" for short, was launched in January 2011 by the National Natural Science Foundation (NSFC) of China. This venture represents the first ever large-scale basic-research program in ocean science in the country (Wang, 2012).

  1. A nearly modern amphibious bird from the Early Cretaceous of northwestern China.

    PubMed

    You, Hai-Lu; Lamanna, Matthew C; Harris, Jerald D; Chiappe, Luis M; O'connor, Jingmai; Ji, Shu-An; Lü, Jun-Chang; Yuan, Chong-Xi; Li, Da-Qing; Zhang, Xing; Lacovara, Kenneth J; Dodson, Peter; Ji, Qiang

    2006-06-16

    Three-dimensional specimens of the volant fossil bird Gansus yumenensis from the Early Cretaceous Xiagou Formation of northwestern China demonstrate that this taxon possesses advanced anatomical features previously known only in Late Cretaceous and Cenozoic ornithuran birds. Phylogenetic analysis recovers Gansus within the Ornithurae, making it the oldest known member of the clade. The Xiagou Formation preserves the oldest known ornithuromorph-dominated avian assemblage. The anatomy of Gansus, like that of other non-neornithean (nonmodern) ornithuran birds, indicates specialization for an amphibious life-style, supporting the hypothesis that modern birds originated in aquatic or littoral niches.

  2. Potential impacts of northeastern Eurasian snow cover on generation of dust storms in northwestern China during spring

    NASA Astrophysics Data System (ADS)

    Lee, Yun Gon; Ho, Chang-Hoi; Kim, Jhoon; Kim, Jinwon

    2013-08-01

    The effects of the northeastern Eurasian snow cover on the frequency of spring dust storms in northwestern China have been examined for the period 1979-2007. Averaged over all 43 stations in northwestern China, a statistically significant relationship has been found between dust-storm frequency (DSF) and Eurasian snow-water equivalent (SWE) during spring: mean DSF of 7.4 and 3.3 days for years of high- and low SWE, respectively. Further analyses reveal that positive SWE anomalies enhance the meridional gradients of the lower tropospheric temperatures and geopotential heights, thereby strengthening westerly jets and zonal wind shear over northwestern China and western Inner Mongolia of China, the regions of major dust sources. The anomalous atmospheric circulation corresponding to the Eurasian SWE anomalies either reinforces or weakens atmospheric baroclinicity and cyclogenesis, according to the sign of the anomaly, to affect the spring DSF. This study suggests that Eurasian SWE anomalies can be an influential factor of spring DSF in northwestern China and western Inner Mongolia of China.

  3. Crustal and uppermost mantle velocity structure beneath northwestern China revealed by ambient noise tomography

    NASA Astrophysics Data System (ADS)

    Li, H.; Li, S.; Song, X.; Gong, M.; Li, X.; Jia, J.

    2010-12-01

    In this study three-component ambient noise data recorded at 148 seismic stations from newly upgraded provincial digital seismic network in northwestern China and adjacent region are used to obtain Rayleigh wave and Love wave group velocity maps. Cross-correlations are calculated in one-hour segments and stacked over 9 months from 2009 January to September to estimate empirical Rayleigh and Love wave Green's functions. Group velocity dispersion curves for both Rayleigh and Love waves between 7 s and 50 s periods were measured for each interstation path by applying the multiple filter analysis method with phase-matched processing. Our group velocity maps show clear lateral variations which are correlated well with major geological structures and tectonic units in the study region. Shear wave velocity structures are then inverted and show that the Tibetan Plateau has a very thick crust with a low-velocity zone in its mid-to-lower crust. Along the northern margin of the plateau with a steep topographic gradient, the low-velocity zone does not extend to the Tarim basin which may indicate that crustal materials beneath the Tarim basin are colder and stronger than beneath the plateau, therefore inhibit the extension of crustal flow and deformation of the Tibetan Plateau, resulting in very sharp topography contrasts. In the northeastern margin where the Tibetan Plateau, Alashan block and Ordos platform collided together, the low-velocity zone diminishes around the eastern end of the KunLun fault. Meanwhile, our results also reveal obvious lateral velocity changes in the crust beneath the Tarim basin. In the upper crust, the Manjaer depression is featured with very low velocities and the Bachu uplift with high velocities; in the mid-to-lower crust, the northern basin overall displays lower velocities than the southern part along the latitude 40°N with a west-east striking which is consistent with the high magnetic anomaly zone and may related to the central suture belt

  4. The rural carbonaceous aerosols in coarse, fine, and ultrafine particles during haze pollution in northwestern China.

    PubMed

    Zhu, Chong-Shu; Cao, Jun-Ji; Tsai, Chuen-Jinn; Shen, Zhen-Xing; Liu, Sui-Xin; Huang, Ru-Jin; Zhang, Ning-ning; Wang, Ping

    2016-03-01

    The carbonaceous aerosol concentrations in coarse particle (PM10: Dp ≤ 10 μm, particulate matter with an aerodynamic diameter less than 10 μm), fine particle (PM2.5: Dp ≤ 2.5 μm), and ultrafine particle (PM0.133: Dp ≤ 0.133 μm) carbon fractions in a rural area were investigated during haze events in northwestern China. The results indicated that PM2.5 contributed a large fraction in PM10. OC (organic carbon) accounted for 33, 41, and 62 % of PM10, PM2.5, and PM0.133, and those were 2, 2.4, and 0.4 % for EC (elemental carbon) in a rural area, respectively. OC3 was more abundant than other organic carbon fractions in three PMs, and char dominated EC in PM10 and PM2.5 while soot dominated EC in PM0.133. The present study inferred that K(+), OP, and OC3 are good biomass burning tracers for rural PM10 and PM2.5, but not for PM0.133 during haze pollution. Our results suggest that biomass burning is likely to be an important contributor to rural PMs in northwestern China. It is necessary to establish biomass burning control policies for the mitigation of severe haze pollution in a rural area.

  5. Seroprevalence of Toxoplasma gondii infection in dairy goats in Shaanxi Province, Northwestern China

    PubMed Central

    2011-01-01

    Background Toxoplasma gondii is an important zoonotic pathogen causing significant human and animal health problems. Infection in dairy goats not only results in significant reproductive losses, but also represents an important source of human infection due to consumption of infected meat and milk. In the present study we report for the first time seroprevalence of T. gondii infection in Guanzhong and Saanen dairy goats in Shaanxi province, Northwestern China. Results Sera from 751 dairy goats from 9 farms in 6 counties were examined for T. gondii antibodies with an indirect haemagglutination (IHA) test. Antibodies to T. gondii were detected in 106 (14.1%) serum samples, with antibody titres ranging from 1:64 to 1:1024. Seropositive goats were found in all 9 farms and seroprevalences in Guanzhong (16.3%, 75/461) and Saanen (10.7%, 31/290) dairy goats were not statistically significantly different. All the factors (sex, age and location) reported in the present study affected prevalence of infection, and seroprevalence increased with age, suggesting postnatal acquisition of T. gondii infection. Conclusions The results of the present survey indicate that infection by T. gondii is widely prevalent in dairy goats in Shaanxi province, Northwestern China, and this has implications for prevention and control of toxoplasmosis in this province. PMID:21457538

  6. Tectonic implications of tomographic images of subducted lithosphere beneath Northwestern South America

    SciTech Connect

    Van Der Hilst, R. ); Mann, P. )

    1993-02-01

    Tomographic images and deep seismicity of the mantle beneath northwestern South America support the existence of extensive and continuous subducted slabs which may be important controls on the neotectonic deformation of the overriding South America plate. Using tomographic data, we have estimated lateral continuity, regional dip, downdip length and approximate convergence direction of two, largely aseismic slabs. Tomographic data suggests that the Cauca slab, previously defined using earthquakes beneath southern Colombia, extends 300 km into the mantle beneath northern Colombia, has an average dip of 50[degrees], and is the downdip extension of Eocene to Miocene Panama island arc and Oligocene-Miocene oceanic crust of the Nazca plate. The Maracaibo slab of northern Colombia and western Venezuela extends up to 450 km into the mantle at an average angle of 16[degrees] and is the downdip extension of Late Cretaceous oceanic plateau crust of the Caribbean Sea. The boundary between the two slabs is less than 50 km in width. The Maracaibo and northern Cauca slabs are generally aseismic and not associated with an overlying volcanic arc. Instead, both slabs are overlain by broad zones of diffuse active faulting and topography in the northern Andes. The shallow dip, angle of oblique subduction and thickness of the Maracaibo slab may produce crustal deformation including northward tectonic escape of the Maracaibo block, a triangular wedge of continental crust in the overriding South America plate.

  7. Near-surface air temperature lapse rates in Xinjiang, northwestern China

    NASA Astrophysics Data System (ADS)

    Du, Mingxia; Zhang, Mingjun; Wang, Shengjie; Zhu, Xiaofan; Che, Yanjun

    2017-01-01

    Lapse rates of near-surface (2 m) air temperature are important parameters in hydrologic and climate simulations, especially for the mountainous areas without enough in-situ observations. In Xinjiang, northwestern China, the elevations range from higher than 7000 m to lower than sea level, but the existing long-term meteorological measurements are limited and distributed unevenly. To calculate lapse rates in Xinjiang, the daily data of near-surface air temperature (T min, T ave, and T max) were measured by automatic weather stations from 2012 to 2014. All the in situ observation stations were gridded into a network of 1.5° (latitude) by 1.5° (longitude), and the spatial distribution and the daily, monthly, seasonal variations of lapse rates for T min, T ave, and T max in Xinjiang are analyzed. The Urumqi River Basin has been considered as a case to study the influence of elevation, aspect, and the wet and dry air conditions to the T min, T ave, and T max lapse rates. Results show that (1) the lapse rates for T min, T ave, and T max vary spatially during the observation period. The spatial diversity of T min lapse rates is larger than that of T ave, and that of T max is the smallest. For each season, T max lapse rates have more negative values than T ave lapse rates which are steeper than T min lapse rates. The weakest spatial diversity usually appears in July throughout a year. (2) The comparison for the three subregions (North, Middle, and South region) exhibits that lapse rates have similar day-to-day and month-to-month characteristics which present shallower values in winter months and steeper values in summer months. The T ave lapse rates in North region are shallower than those in Middle and South region, and the steepest T ave lapse rates of the three regions all appear in April. T min lapse rates are shallower than T max lapse rates. The maximum medians of T min and T max lapse rates for each grid in the three regions all appear in January, whereas the

  8. Paleozoic-early Mesozoic gold deposits of the Xinjiang Autonomous Region, northwestern China

    USGS Publications Warehouse

    Rui, Z.; Goldfarb, R.J.; Qiu, Y.; Zhou, T.; Chen, R.; Pirajno, F.; Yun, G.

    2002-01-01

    The late Paleozoic-early Mesozoic tectonic evolution of Xinjiang Autonomous Region, northwestern China provided a favorable geological setting for the formation of lode gold deposits along the sutures between a number of the major Eastern Asia cratonic blocks. These sutures are now represented by the Altay Shan, Tian Shan, and Kunlun Shan ranges, with the former two separated by the Junggar basin and the latter two by the immense Tarim basin. In northernmost Xinjiang, final growth of the Altaid orogen, southward from the Angara craton, is now recorded in the remote mid- to late Paleozoic Altay Shan. Accreted Early to Middle Devonian oceanic rock sequences contain typically small, precious-metal bearing Fe-Cu-Zn VMS deposits (e.g. Ashele). Orogenic gold deposits are widespread along the major Irtysh (e.g. Duyolanasayi, Saidi, Taerde, Kabenbulake, Akexike, Shaerbulake) and Tuergen-Hongshanzui (e.g. Hongshanzui) fault systems, as well as in structurally displaced terrane slivers of the western Junggar (e.g. Hatu) and eastern Junggar areas. Geological and geochronological constraints indicate a generally Late Carboniferous to Early Permian episode of gold deposition, which was coeval with the final stages of Altaid magmatism and large-scale, right-lateral translation along older terrane-bounding faults. The Tian Shan, an exceptionally gold-rich mountain range to the west in the Central Asian republics, is only beginning to be recognized for its gold potential in Xinjiang. In this easternmost part to the range, northerly- and southerly-directed subduction/accretion of early to mid-Paleozoic and mid- to late Paleozoic oceanic terranes, respectively, to the Precambrian Yili block (central Tian Shan) was associated with 400 to 250 Ma arc magmatism and Carboniferous through Early Permian gold-forming hydrothermal events. The more significant resulting deposits in the terranes of the southern Tian Shan include the Sawayaerdun orogenic deposit along the Kyrgyzstan border and

  9. The asymmetric distribution of phytoplankton in anticyclonic eddies in the western South China Sea

    NASA Astrophysics Data System (ADS)

    Liu, Fenfen; Tang, Shilin; Huang, Rui Xin; Yin, Kedong

    2017-02-01

    An anticyclonic eddy's periphery is characterized by large horizontal density gradients, strain and vertical velocity. In this paper we document the asymmetric distribution of phytoplankton around the periphery of anticyclonic eddies in the western South China Sea based on 432 eddies detected from satellite data. The high level of phytoplankton occurs consistently at the northwestern periphery of eddies, with a maximum positive chlorophyll anomaly greater than 0.01 mg m-3. The asymmetric distribution of phytoplankton primarily tags the non-uniform surface velocity field varying from 0.15 m s-1 to 0.3 m s-1 along the eddy's periphery. The coastal boundary and off-coast jet may be the primary cause of the non-uniform flow. Associated with the non-uniform flow speed, the combined effects of the velocity convergence and steepened northwestern part of the eddies act to sharpen the density fronts and tend to result in an ageostrophic secondary circulation at the northwestern edge of the eddy. The upward component of the ageostrophic secondary circulation can enhance the nutrient flux into the euphotic layer, thereby increasing phytoplankton productivity. Anticyclonic eddy-induced ageostrophic secondary circulation appears to be an important mechanism for increasing phytoplankton productivity in the oligotrophic waters of the South China Sea.

  10. Spatial relationships among species, above-ground biomass, N, and P in degraded grasslands in Ordus Plateau, northwestern China

    Treesearch

    X. Cheng; S. An; J. chen; B. Li; Y. Liu; S. Liu

    2007-01-01

    We chose five communities, representing a mild to severe gradient of grassland desertification in a semi-arid area of Ordos Plateau, northwestern China, to explore the spatial relationships among plant species, above-ground biomass (AGB), and plant nutrients (N and P). Community 1 (Cl) was dominated by Stipa bungeana; community 2 (C2) by a mix of S...

  11. Geological history of the Cretaceous ophiolitic complexes of northwestern South America (Colombian Andes)

    NASA Astrophysics Data System (ADS)

    Bourgois, Jacques; Toussaint, Jean-François; Gonzalez, Humberto; Azema, Jacques; Calle, Bernardo; Desmet, Alain; Murcia, Luis A.; Acevedo, Alvaro P.; Parra, Eduardo; Tournon, Jean

    1987-12-01

    The Western Cordillera of Colombia was formed by intense alpine-type nappe-forming folding and thrusting. The Cretaceous (80-120 Ma B.P.) tholeiitic material of the Western Cordilleran nappes has been obducted onto the Paleozoic and Precambrian polymetamorphic micaschists and gneiss of the Central Cordillera. Near Yarumal, the Antioquia batholith (60-80 Ma B.P.) intrudes both obducted Cretaceous oceanic material and the polymetamorphic basement rock of the Central Cordillera. Therefore, nappe emplacement and obduction onto the Central Cordillera occurred during Late Senonian to Early Paleocene. The nappes travelled from northwest to southeast so that the highest unit, the Rio Calima nappe therefore has the most northwestern source, whereas the lowest units originated from a more southeastward direction. Sedimentological analysis of the volcanoclastic and sandy turbidite material from each unit suggests a marginal marine environment. During Cretaceous times the opening of this marginal sea, from now on called the "Colombia marginal basin", probably originated by detachment of a block from the South American continent related to the Farallon-South America plate convergence. In the Popayan area (southern Colombia), the Central Cordilleran basement exhibits glaucophane schist facies metamorphism. This high pressure low temperature metamorphism is of Early Cretaceous (125 Ma B.P.) age and is related to an undated metaophiolitic complex. The ophiolitic material originating from the Western Cordilleran is thrust over both the blueschist belt and the metaophiolitic complex. These data suggest that the "Occidente Colombiano" suffered at least two phases of ophiolitic obduction during Mesozoic time.

  12. Some characteristics of ozone concentrations and their linkages with meteorological factors in Kashgar, northwestern China

    NASA Astrophysics Data System (ADS)

    Wang, Huiqin; Mamtimin, Mamtali; Chen, Feng

    2017-07-01

    Observations of O3 and NO2 have been performed in Kashgar, northwestern China, from January to December 2015. We analyze the variations of O3 and NO2 daily, the diurnal variations of O3 and NO2 as well as the relation between O3 and NO2 concentrations. We focused on the variations of O3, with the meteorological factors. We find that there exist to some extent between meteorological factors and O3 concentrations. High O3 concentrations were related to high temperature, low relative humidity, low cloudiness, and light wind speed. The local meteorological conditions on certain situations also influenced the ozone concentration. Preliminary statistics of the occurrence frequencies of high ozone concentration days corresponding to some meteorological factors are given in this paper.

  13. Aerosol direct radiative forcing in desert and semi-desert regions of northwestern China

    NASA Astrophysics Data System (ADS)

    Xin, Jinyuan; Gong, Chongshui; Wang, Shigong; Wang, Yuesi

    2016-05-01

    The optical properties of dust aerosols were measured using narrow-band data from a portable sun photometer at four desert and semi-desert stations in northwestern China from 2004 to 2007. Ground-based and satellite observations indicated absorbing dust aerosol loading over the region surrounded by eight large-scale deserts. Radiation forcing was identified by using the Santa Barbara DISORT Atmospheric Radiative Transfer (SBDART) model. The ranges of annual mean aerosol optical depth (AOD), Angström exponents, and single-scattering albedo (SSA) were from 0.25 to 0.35, from - 0.73 to 1.18, and from 0.77 to 0.86, respectively. The ranges of annual mean aerosol direct radiative forcing values at the top of the atmosphere (TOA), mid-atmosphere, and on the surface were from 3.9 to 12.0, from 50.0 to 53.1, and from - 39.1 to - 48.1 W/m2, respectively. The aerosols' optical properties and radiative characteristics showed strong seasonal variations in both the desert and semi-desert regions. Strong winds and relatively low humidity will lead dust aerosols in the atmosphere to an increase, which played greatly affected these optical properties during spring and winter in northwestern China. Based on long-term observations and retrieved data, aerosol direct radiative forcing was confirmed to heat the atmosphere (50-53 W/m2) and cool the surface (- 39 to - 48 W/m2) above the analyzed desert. Radiative forcing in the atmosphere in spring and winter was 18 to 21 W/m2 higher than other two seasons. Based on the dust sources around the sites, the greater the AOD, the more negative the forcing. The annual averaged heating rates for aerosols close to the ground (1 km) were approximately 0.80-0.85 K/day.

  14. Prevalence of Anaplasma phagocytophilum in ruminants, rodents and ticks in Gansu, north-western China.

    PubMed

    Yang, Jifei; Liu, Zhijie; Guan, Guiquan; Liu, Qing; Li, Youquan; Chen, Ze; Ma, Miling; Liu, Aihong; Ren, Qiaoyun; Luo, Jianxun; Yin, Hong

    2013-02-01

    The zoonotic rickettsial pathogen Anaplasma phagocytophilum has a broad geographical distribution and a high degree of biological and clinical diversity. To determine the prevalence of Anaplasma phagocytophilum in the Gannan Tibetan Autonomous Prefecture of Gansu Province, north-western China, four ruminant species, one rodent and one tick species were examined for Anaplasma phagocytophilum infection. DNA from Anaplasma phagocytophilum was detected by nested PCR in blood samples from 21/49 sheep (42.9 %), 35/91 goats (38.5 %), 51/158 yaks (32.3 %) and 7/20 cattle-yaks (35.0 %), and in spleen samples from 2/12 rodents (16.7 %). For samples from tick larvae and nymphs, 105 pools were tested; one of 46 larval tick pools was positive and seven of 59 nymphal tick pools were positive. For adult ticks, 40/598 female ticks (6.7 %) and 26/528 male ticks (4.9 %) were positive. The prevalence of Anaplasma phagocytophilum in female ticks was higher than that in males, although the difference was not statistically significant (P>0.05). Sequences analysis based on the 16S rRNA gene indicated that the strains in the study area were distinct from previously reported Anaplasma phagocytophilum in other continents. These results add new information on the epidemiology of Anaplasma phagocytophilum and indicate the tick-animal cycle of anaplasmosis in the area. To the best of our knowledge, this is the first report of Anaplasma phagocytophilum infection in Gansu Province in north-western China.

  15. Transition from slab stagnation to penetration beneath the northwestern Pacific and South America (Invited)

    NASA Astrophysics Data System (ADS)

    Fukao, Y.; Obayashi, M.

    2010-12-01

    Subducting slabs tend to once deflect horizontally in the transition zone as stagnant slabs and then to penetrate into the lower mantle across the 660-km discontinuity. Here we present the detailed tomographic images of transition from stagnant-slab mode to penetrating-slab mode, based on the global ISC travel time data to which regional network data and long-term array observation data including ocean bottom data are added. The targets are the subducted slabs beneath South America and the northwestern Pacific. In South America the transition occurs across the northeastward extension of the sharp bend of the Peru-Chili trench. The slab to the south of this extension is stagnant above the 660, and to the north it plunges into the lower mantle across the 660. The transition is sharp as if the originally flat slab in the northern part was rotated into the present configuration by hinge faulting along the extension. We suspect that this hinge faulting either triggered the northward propagation of or truncated the southward propagation of the plunging motion of the slab into the lower mantle. Along the Kurile arc, the slab is flattened above the 660 in the southwest, penetrating in the northeast, with a transitional feature in between. In southern Kurile the flattened part has a deepest bottom near the junction with the dipping part. Such an along-arc change of slab configuration is indicative of a process of transition from stagnant-slab mode to penetrating-slab mode: the flattened part and dipping part of the slab begin to sink into the lower mantle at their junction so that the horizontal part is progressively dragged to and is eventually united to the dipping part as a penetrating slab. Along the Izu-Bonin-Mariana (IBM) arc, the slab is flattened above the 660 in the north (Izu-Bonin) and is penetrating the 660 in the south (Mariana) leaving the horizontal part in the transition zone. In the Izu-Bonin the flattened part has a deepest bottom near the junction with

  16. Vegetation ecological water requirement in South China

    NASA Astrophysics Data System (ADS)

    Wan, Long; Liu, Yuguo; Guan, Yinghui; Zhou, Jinxing; Cui, Ming

    2017-04-01

    South China covered about 20% of the total area of China, with two big rivers, Yangtze River and the Pearl River get through this area. The karst landform are widely distributed in this area. Intensive vegetation degradation and severe rocky desertification have threatened the local ecological security. Water has been a key factor limiting the eco-restoration and construction of the vegetation. However, we do not know whether the water can satisfy the vegetation ecological water demand in this area. In this study, we explored the minimum and suitable ecological water requirement and the water use efficiency in South China based on the MOD16 datasets. The results indicated that the mean value of the minimum ecological water requirement is 528.9mm in South China, and the suitable water requirement is 686.8mm. In many parts of the Sichuan, Yunnan, Hubei Provinces, water cannot meet the minimum ecological water requirements. There needs about 100-300mm to meet the minimum ecological water requirements in these areas. The ecological water requirements in the karst area and the non-karst area were 520mm and 532mm. Severer Rocky desertification areas need more ecological water than light and potential rocky desertification area. Water requirements are also different for the different land use type. The suitable ecological water requirement lack of 89mm-136mm in the Evergreen Needle-leaf Forest, Mixed Forest, Closed Scrubland and the Croplands. Water use efficiency in the Evergreen Broad-leaf forests, Evergreen Needle-leaf Forest, Mixed Forest, Closed Scrubland were more than 1kg/m3, but in the croplands was 0.9-1kg/m3, and in the grassland was only 0.6-0.8 kg/m3. This research could be helpful for improving water resource management and the rocky desertification management in South China.

  17. Molecular evidence of tick-borne pathogens in Hyalomma anatolicum ticks infesting cattle in Xinjiang Uygur Autonomous Region, Northwestern China.

    PubMed

    Yu, Peifa; Liu, Zhijie; Niu, Qingli; Yang, Jifei; Abdallah, Mirza Omar; Chen, Ze; Liu, Guangyuan; Luo, Jianxun; Yin, Hong

    2017-09-05

    Although tick-borne pathogens have been widely reported in ticks in China, there is little information available on the prevalence of information in Hyalomma ticks from cattle. This study aims to determine the occurrence of pathogens in Hyalomma anatolicum collected from cattle in Xinjiang Uygur Autonomous Region, China, by PCR, sequencing and phylogenetic analysis. Borrelia burgdorferi s.s., Rickettsia massiliae and Anaplasma bovis were identified, whereas DNA of Ehrlichia species and an Anaplasma platys-like pathogen were also detected. Our findings highlight the risk of infection of animals and humans with these pathogens in north-western China.

  18. Bluetongue disease and seroprevalence in South American camelids from the northwestern region of the United States.

    PubMed

    Allen, Andrew J; Stanton, James B; Evermann, James F; Fry, Lindsay M; Ackerman, Melissa G; Barrington, George M

    2015-03-01

    In late summer/early fall of 2013, 2 South American camelids from central Washington were diagnosed with fatal bluetongue viral disease, an event which is rarely reported. A 9-year-old intact male llama (Lama glama), with a 1-day history of anorexia, recumbency, and dyspnea before death. Abundant foam discharged from the mouth and nostrils, and the lungs were severely edematous on postmortem examination. Histologically, there was abundant intra-alveolar edema with fibrin. Hemorrhage and edema disrupted several other organs. Bluetongue viral RNA was detected by reverse transcription polymerase chain reaction (RT-PCR), and serotype 11 was identified by sequencing a segment of the VP2 outer capsid gene. Approximately 1 month later, at a site 150 miles north of the index case, a 2-year-old female alpaca with similar, acutely progressive clinical signs was reported. A postmortem examination was performed, and histologic lesions from the alpaca were similar to those of the llama, and again serotype 11 was detected by PCR. The occurrence of bluetongue viral infection and disease is described in the context of seasonal Bluetongue virus activity within the northwestern United States and southwestern Canada.

  19. Previously Unrecognized Ornithuromorph Bird Diversity in the Early Cretaceous Changma Basin, Gansu Province, Northwestern China

    PubMed Central

    Wang, Ya-Ming; O'Connor, Jingmai K.; Li, Da-Qing; You, Hai-Lu

    2013-01-01

    Here we report on three new species of ornithuromorph birds from the Lower Cretaceous Xiagou Formation in the Changma Basin of Gansu Province, northwestern China: Yumenornis huangi gen. et sp. nov., Changmaornis houi gen. et sp. nov., and Jiuquanornis niui gen. et sp. nov.. The last of these is based on a previously published but unnamed specimen: GSGM-05-CM-021. Although incomplete, the specimens can be clearly distinguished from each other and from Gansus yumenensis Hou and Liu, 1984. Phylogenetic analysis resolves the three new taxa as basal ornithuromorphs. This study reveals previously unrecognized ornithuromorph diversity in the Changma avifauna, which is largely dominated by Gansus but with at least three other ornithuromorphs. Body mass estimates demonstrate that enantiornithines were much smaller than ornithuromorphs in the Changma avifauna. In addition, Changma enantiornithines preserve long and recurved pedal unguals, suggesting an arboreal lifestyle; in contrast, Changma ornithuromorphs tend to show terrestrial or even aquatic adaptions. Similar differences in body mass and ecology are also observed in the Jehol avifauna in northeastern China, suggesting niche partitioning between these two clades developed early in their evolutionary history. PMID:24147058

  20. Seroprevalence and Risk Factors of Toxoplasma gondii in Slaughter Pigs in Shaanxi Province, Northwestern China.

    PubMed

    Wu, Fei; Wang, Ya-Lin; Yang, Zhao; Li, Xi-Lai; Li, Zong-Ren; Lin, Qing

    2017-07-01

    Toxoplasma gondii is an important food-borne zoonotic protozoan parasite, which can infect endothermic animals, including pigs. However, data on T. gondii in slaughter pigs in Shaanxi Province were still lacking. To detect the seroprevalence and analyze the risk factors of T. gondii infection in slaughter pigs in Shaanxi Province, Northwestern China, a total of 784 serum samples were collected from four administrative regions and detected by indirect hemagglutination test for T. gondii infection. Antibodies to T. gondii were found in 19.9% (156/784) slaughter pigs. Moreover, the seropositive rate was different among rearing systems (31% in nonintensive pig farms and 6.7% in intensive pig farms), genders (19.8% in male and 20.0% in female), and regions (ranging from 6.7% in Shenmu to 38.2% in Zhouzhi). Rearing system and region were identified as risk factors for T. gondii infection. These results showed that T. gondii is highly prevalent in slaughter pigs in Shaanxi Province, and it could cause a serious risk to public health. This study provided fundamental information for the prevention and control of T. gondii infection in slaughter pigs in China.

  1. Environmental impacts of large-scale CSP plants in northwestern China.

    PubMed

    Wu, Zhiyong; Hou, Anping; Chang, Chun; Huang, Xiang; Shi, Duoqi; Wang, Zhifeng

    2014-01-01

    Several concentrated solar power demonstration plants are being constructed, and a few commercial plants have been announced in northwestern China. However, the mutual impacts between the concentrated solar power plants and their surrounding environments have not yet been addressed comprehensively in literature by the parties involved in these projects. In China, these projects are especially important as an increasing amount of low carbon electricity needs to be generated in order to maintain the current economic growth while simultaneously lessening pollution. In this study, the authors assess the potential environmental impacts of large-scale concentrated solar power plants. Specifically, the water use intensity, soil erosion and soil temperature are quantitatively examined. It was found that some of the impacts are favorable, while some impacts are negative in relation to traditional power generation techniques and some need further research before they can be reasonably appraised. In quantitative terms, concentrated solar power plants consume about 4000 L MW(-1) h(-1) of water if wet cooling technology is used, and the collectors lead to the soil temperature changes of between 0.5 and 4 °C; however, it was found that the soil erosion is dramatically alleviated. The results of this study are helpful to decision-makers in concentrated solar power site selection and regional planning. Some conclusions of this study are also valid for large-scale photovoltaic plants.

  2. Previously unrecognized ornithuromorph bird diversity in the Early Cretaceous Changma Basin, Gansu Province, northwestern China.

    PubMed

    Wang, Ya-Ming; O'Connor, Jingmai K; Li, Da-Qing; You, Hai-Lu

    2013-01-01

    Here we report on three new species of ornithuromorph birds from the Lower Cretaceous Xiagou Formation in the Changma Basin of Gansu Province, northwestern China: Yumenornis huangi gen. et sp. nov., Changmaornis houi gen. et sp. nov., and Jiuquanornis niui gen. et sp. nov.. The last of these is based on a previously published but unnamed specimen: GSGM-05-CM-021. Although incomplete, the specimens can be clearly distinguished from each other and from Gansus yumenensis Hou and Liu, 1984. Phylogenetic analysis resolves the three new taxa as basal ornithuromorphs. This study reveals previously unrecognized ornithuromorph diversity in the Changma avifauna, which is largely dominated by Gansus but with at least three other ornithuromorphs. Body mass estimates demonstrate that enantiornithines were much smaller than ornithuromorphs in the Changma avifauna. In addition, Changma enantiornithines preserve long and recurved pedal unguals, suggesting an arboreal lifestyle; in contrast, Changma ornithuromorphs tend to show terrestrial or even aquatic adaptions. Similar differences in body mass and ecology are also observed in the Jehol avifauna in northeastern China, suggesting niche partitioning between these two clades developed early in their evolutionary history.

  3. Geology and timing of mineralization at the Cangshang gold deposit, north-western Jiaodong Peninsula, China

    USGS Publications Warehouse

    Zhang, X.; Cawood, Peter A.; Wilde, S.A.; Liu, R.; Song, H.; Li, W.; Snee, L.W.

    2003-01-01

    The Cangshang gold deposit of the northwestern Jiaodong Peninsula contains reserves of greater than 50 tonnes (t) and is developed by the largest open pit gold mine in China. This deposit is a Jiaojia-style (i.e. disseminated-and-veinlet) deposit. It is controlled by the San-Cang fault zone, which trends ???040?? and dips 40-75??SE at the mine site. The main (no. 1) orebody lies between a hanging wall of Precambrian metamorphic rocks (mainly amphibolite) of the Fenzishan Group and a footwall composed of the Mesozoic Linglong granitoid. The ore zone is mainly composed of pyritized, sericitized and silicified granitoid, which has undergone variable degrees of cataclasis. SHRIMP U-Pb dating of zircon indicates that the protolith of the hanging wall amphibolite was formed at 2530 ?? 17 Ma and underwent metamorphism at 1852 ?? 37 Ma. The footwall granodiorite has been dated at 166 ?? 4 Ma, whereas zircons from the ore zone yield a younger age of 154 ?? 5 Ma. Cathodoluminescence images of zircons from the granodiorite and ore zone show oscillatory zonation indicative of an igneous origin for both and the ages of these zircons, therefore, are all interpreted to be representative of magmatic crystallization. Dating of sericite by 40Ar-39Ar has been used to directly determine the timing of formation of the Cangshang deposit, providing the first time absolute age on formation of the Jiaojia-style gold deposits. The well-defined age of 121.3 ?? 0.2 Ma provides the precise timing of gold mineralization at the Cangshang deposit. This age is consistent with those of Linglong-style (vein type) gold mineralization, also from the north-western Jiaodong Peninsula, at between 126 and 120 Ma. Therefore, our work indicates that both styles of gold deposits in the Jiaodong Peninsula were formed during the same mineralization event.

  4. The pattern of curved mafic dike swarm in a Hercynian(?) granitic body, eastern Tianshan orogen (Northern mountain, Gangsu province, northwestern China): genesis and implications

    NASA Astrophysics Data System (ADS)

    Shan, Y.; Suen, B.; Qiao, Y.

    2009-12-01

    In the Northern mountain, northwest of Gangsu province, northwestern China there occurs a set of curved dike swarm in an elliptical Hercynian(?) granitic body (about 35km×15km). This phenomenon is only visible on satellite image. Based upon the abutting and crosscutting relationships observed in the field, four dike sets are recognized in the intrusive body. The first is felsic, and the others mafic. The second set predominates, and makes up the phenomenon of curved dike swarm in the granitic body: a set of densely spaced dikes appears to change their azimuths systematically from the north-northeast in the north to the north-to-south in the middle to the northwest in the south. A simple explanation about the phenomenon is the existence of a single buckle that consists of these curved dikes. However, our field observations do not support this model. They in turn make us believe that the curved dike swarm should have formed to propagate along the curved trajectory of the maximum horizontal principal stress that resulted from local stress perturbation by preexisting fault(s). From the divergent distribution of the first dike set, we argue the presence of a hidden strike-slip fault beneath the granitic body, trending the west to east. Poly3D numerical software was used to address this stress perturbation. The results showed that a relatively large amount of dexterous strike slip along the fault was required to produce the curved stress trajectory in the area. The consolidation of this post-orogenic intrusive body seemed not to have completely healed the hidden fault(s), probably deep-rooted, along which it might have migrated upwards and/or emplaced. A satellite image of curved dike swarm in a granitic body from the Northern mountain, Gangsu, northwestern China. (downloaded from Google Earth)

  5. Divergent population genetic structure of the endangered Helianthemum (Cistaceae) and its implication to conservation in northwestern China

    Treesearch

    Zhihao Su; Bryce A. Richardson; Li Zhuo; Xiaolong Jiang

    2017-01-01

    Population genetic studies provide a foundation for conservation planning, especially for endangered species. Three chloroplast SSRs (mtrnSf-trnGr, mtrnL2-trnF, and mtrnL5-trnL3) and the internal transcribed spacer were used to examine the population structure of Helianthemum in northwestern China. A total of 15 populations of the genus were collected. Nine chloroplast...

  6. Phylogeography of the rare Gymnocarpos przewalskii (Caryophyllaceae): indications of multiple glacial refugia in north-western China

    Treesearch

    S. M. Ma; M. L. Zhang; S. C. Sanderson

    2012-01-01

    We investigated the phylogeography of Gymnocarpos przewalskii Maxim. (Caryophyllaceae), a rare relictual shrub restricted to north-western China, in the context of Quaternary climate oscillations. ThreecpDNAregions (psbA­trnH, ycf6­psbM and rpl32-trnL (UAG)) were sequenced for 160 individuals from 16 populations. High genetic diversity (hT = 0.930, hS = 0.425) and a...

  7. First detection of Candidatus Rickettsia barbariae in the flea Vermipsylla alakurt from north-western China.

    PubMed

    Zhao, Shan-Shan; Li, Hong-Yu; Yin, Xiao-Ping; Liu, Zhi-Qiang; Chen, Chuang-Fu; Wang, Yuan-Zhi

    2016-06-07

    Vermipsylla is a genus of the family Vermipsyllidae within the order Siphonaptera of fleas. Vermipsylla alakurt is mainly distributed in alpine pastoral areas of Kazakhstan, Mongolia, China and Nepal, and infests sheep, yaks and horses, causing irritation, poor condition, anaemia and even death. However, to date, no rickettsial agents have been reported in V. alakurt. A total of 133 fleas were collected directly from the tails of three sheep flocks (n = 335) in Minfeng County, Xinjiang Uygur Autonomous Region, north-western China. Of these, 55 fleas were identified by morphological examination and molecular analysis of four loci (the ribosomal 18S and 28S rDNA genes and the mitochondrial genes cytochrome  c oxidase subunit II and elongation factor 1-alpha). Eight Rickettsia-specific gene fragments originated from seven genes: the 17-kilodalton antigen gene (17-kDa), citrate synthase gene (gltA), 16S rRNA gene (rrs), outer membrane protein A gene (ompA), surface cell antigen 1 gene (sca1), PS120 protein gene (gene D), and outer membrane protein B gene (ompB, two fragments), were used to identify the species of Rickettsia in 53 fleas. The amplified products were sequenced and included in a phylogenetic analysis to verify the taxonomic identification of the rickettsial agents. Based on morphological and molecular evidence, the flea was identified as Vermipsylla alakurt. Nine samples were positive (16.98 %, 9/53) for Rickettsia spp. The phylogenetic tree revealed that the rickettsial agents found in V. alakurt cluster with Candidatus Rickettsia barbariae. Our study suggests that: (i) V. alakurt may serve as a carrier for Candidatus R. barbariae; and (ii) Candidatus R. barbariae, previously reported in Israel, is the eighth newly discovered validated Rickettsia species in China. This finding extends our knowledge of the distribution of Candidatus R. barbariae and the profile of carriers, which not only comprise ticks but also fleas.

  8. New Navy Fighting Machine in the South China Sea

    DTIC Science & Technology

    2012-06-01

    MACHINE IN THE SOUTH CHINA SEA by Dylan B. Ross Jimmy A. Harmon June 2012 Thesis Advisor: Raymond Buettner Second Reader: Wayne P...COVERED Master’s Thesis 4. TITLE AND SUBTITLE New Navy Fighting Machine in the South China Sea 5. FUNDING NUMBERS 6. AUTHOR(S) Dylan B. Ross...combatants can defeat PRC anti-access area denial (A2AD) measures in the South China Sea (SCS). Hughes’ equation reveals that advantages for American surface

  9. Secondary salinization and evapotranspiration under mulched drip irrigation condition in Tarim River basin of northwestern China

    NASA Astrophysics Data System (ADS)

    Tian, Fuqiang; Hu, Hongchang; Zhang, Zhi; Hu, Heping

    2013-04-01

    The secondary salinization induced by irrigation has been presented as a crucial threat to agriculture all over the world, especially in semi-arid and arid regions. Mulched drip irrigation (MDI), as a new micro-irrigation approach incorporating surface drip irrigation method and film mulching technique, has been widely applied in water scarce regions including Tarim River basin of northwestern China. However, salts are likely to build up in the surface soil due to the deficient leaching water in such an irrigation condition. To explore this new kind of secondary salinization issue, the oasis eco-hydrology experimental research station were established in 2008 in a cotton field of Xinjiang, northwestern China. More than 40,000 soil samples were collected to monitor soil moisture and salinity condition within the 1.5 meter depth. The patterns of soil salinity distribution under MDI along the horizontal direction as well as vertical direction have been explored. The results did show that secondary salinization tends to occur in the experimental field under mulched drip irrigation, and winter flush could leach most soil salt in the root zone into groundwater and keep salt balance to mitigate the soil salinization. Meanwhile, soil salt always migrates with the soil water flux such as irrigation and groundwater recharge. Therefore the understanding of water balance is of great importance for estimating soil salinity accumulation, of which evapotranspiration (ET) is the key process, especially in the semi-arid and arid area. In our study, in order to quantify the relation between salinity balance and water balance, ET were derived from a range of measurement systems including eddy covariance, soil water budget (gravimetric methods, Hydra probe, TDT probe and groundwater table sensor, et al.), sap flow and portable photosynthetic system during cotton growing period. Our study is unique in its focus on ET scale issue ranging from leaf and plant scale to field. The up

  10. [Analysis of pathogen spectrum of Encephalitis/Meningitis in northwestern area of China].

    PubMed

    Zhang, Xiao-shu; Wang, Xu-xia; Yu, De-shan; Jiang, Jian-xiang; Zhang, Guang-ye; Wang, Fang; Li, Hui

    2013-10-01

    To learn the characteristics of pathogen spectrum of Encephalitis /Meningitis in northwestern area of China. Between January 1st 2009 and March 31st 2011, a total of 569 patients with clinical symptoms of Encephalitis/Meningitis were selected from the hospitals in Gansu, Qinghai,Inner Mongolia and Xinjiang province. 1514 samples of specimen were collected from the 515 patients, to detect the IgM of Japanese encephalitis virus (JEV), enterovirus (EV, including Coxsackie virus, ECHO virus and enterovirus 71), Mumps virus, Herpes simplex virus (HSV) in blood and cerebrospinal fluid. Meanwhile, Neisseria meningitis (Nm), Haemophilus influenzae Type B (Hib), Staphylococcus, Streptococcus pneumonia, Streptococcus Suis, E. Coli and Cryptococci were also identified. The detection results were analyzed by different region, time and age range. Pathogenic bacteria were identified in the specimen from 16 patients, with the rate at 3.65%, of which the dominant ones were Streptococcus pneumonia (7 patients, 43.75%). Virus were identified in the specimen from 132 patients, with the rate at 27.05%, of which the dominant types were EV and HSV, accounting for 33.33% (44 cases) and 31.82% (42 cases) respectively. The detection rate of virus showed a significant seasonal trend, with the peak appearing between June and November each year. The peak of EV detection was between July and September, with 24 cases detected out; the peak of HSV was between June and August (11 cases detected out); mumps virus was mainly found between July and December (25 cases). There was no significant time-distribution found in the detection of bacteria. The EV and HSV were mainly distributed in Gansu and Qinghai province (70 cases) ;most of mumps virus were found in Gansu province (24 cases);and JEV were only found in Gansu province (20 cases). The viral pathogen spectrum was identified in all ages, and the EV and mumps virus were mainly found in children aged 0-14 years old (42 and 17 cases respectively

  11. Multivariate indications between environment and ground water recharge in a sedimentary drainage basin in northwestern China

    NASA Astrophysics Data System (ADS)

    Zhu, Bingqi; Wang, Xunming; Rioual, Patrick

    2017-06-01

    A paucity of studies on the interaction between environment and ground water recharge severely restricts the ability of people to assess future water resources under changing environment. In this study, an effort to explore the relationship between the arid environment and ground water recharge was carried out using multivariate statistical techniques in a sedimentary drainage basin (the Jungar) in northwestern China. Hierarchical cluster analysis (HCA) and principal components analysis (PCA) were performed based on hydrogeochemical data to assess the ground water recharge and its governing factors. Observation of the HCA and PCA analytical results revealed a division of seven clusters (C1 to C7) and three principal components (PC1 to PC3), which explained 59.6%, 16.6% and 10.9% of the variance, respectively, and thus, accounted for the majority of the total variance in the original dataset. Based on these Q-mode HCA clusters and R-mode PAC scores, dominant environmental processes influencing recharge regimes were identified, i.e., geogenic, geomorphoclimatic, and anthropogenic, which separated the recharge regimes into four zones (Zone I to Zone IV). Zones I and II (C4 + C1) were associated to ;elevated hydroclimate degree; coupled to ;low salinity;. Zone III (C2 + C3) was associated to ;moderately elevated salinity; and evidently ;elevated contamination; but coupled to ;low hydroclimate degree;. Zone IV (C5 + C6 + C7) was associated mainly to ;elevated salinity; coupled to ;low or inverse hydroclimate degree;. It revealed that the geogenic processes are more significant (60%) than the geomorphoclimatic (17%) and anthropogenic (11%) processes. As a result, the overall recharge process is rather heterogeneous and is strongly environment dominated in the Jungar drainage system. Compared with other watersheds in arid environment, a distinctive feature of the Jungar waters is that they are affected by a combination of natural and non-natural events, rather than

  12. Ethnobotanical Knowledge Is Vastly Under-Documented in Northwestern South America

    PubMed Central

    Cámara-Leret, Rodrigo; Paniagua-Zambrana, Narel; Balslev, Henrik; Macía, Manuel J.

    2014-01-01

    A main objective of ethnobotany is to document traditional knowledge about plants before it disappears. However, little is known about the coverage of past ethnobotanical studies and thus about how well the existing literature covers the overall traditional knowledge of different human groups. To bridge this gap, we investigated ethnobotanical data-collecting efforts across four countries (Colombia, Ecuador, Peru, Bolivia), three ecoregions (Amazon, Andes, Chocó), and several human groups (including Amerindians, mestizos, and Afro-Americans). We used palms (Arecaceae) as our model group because of their usefulness and pervasiveness in the ethnobotanical literature. We carried out a large number of field interviews (n = 2201) to determine the coverage and quality of palm ethnobotanical data in the existing ethnobotanical literature (n = 255) published over the past 60 years. In our fieldwork in 68 communities, we collected 87,886 use reports and documented 2262 different palm uses and 140 useful palm species. We demonstrate that traditional knowledge on palm uses is vastly under-documented across ecoregions, countries, and human groups. We suggest that the use of standardized data-collecting protocols in wide-ranging ethnobotanical fieldwork is a promising approach for filling critical information gaps. Our work contributes to the Aichi Biodiversity Targets and emphasizes the need for signatory nations to the Convention on Biological Diversity to respond to these information gaps. Given our findings, we hope to stimulate the formulation of clear plans to systematically document ethnobotanical knowledge in northwestern South America and elsewhere before it vanishes. PMID:24416449

  13. Ethnobotanical knowledge is vastly under-documented in northwestern South America.

    PubMed

    Cámara-Leret, Rodrigo; Paniagua-Zambrana, Narel; Balslev, Henrik; Macía, Manuel J

    2014-01-01

    A main objective of ethnobotany is to document traditional knowledge about plants before it disappears. However, little is known about the coverage of past ethnobotanical studies and thus about how well the existing literature covers the overall traditional knowledge of different human groups. To bridge this gap, we investigated ethnobotanical data-collecting efforts across four countries (Colombia, Ecuador, Peru, Bolivia), three ecoregions (Amazon, Andes, Chocó), and several human groups (including Amerindians, mestizos, and Afro-Americans). We used palms (Arecaceae) as our model group because of their usefulness and pervasiveness in the ethnobotanical literature. We carried out a large number of field interviews (n = 2201) to determine the coverage and quality of palm ethnobotanical data in the existing ethnobotanical literature (n = 255) published over the past 60 years. In our fieldwork in 68 communities, we collected 87,886 use reports and documented 2262 different palm uses and 140 useful palm species. We demonstrate that traditional knowledge on palm uses is vastly under-documented across ecoregions, countries, and human groups. We suggest that the use of standardized data-collecting protocols in wide-ranging ethnobotanical fieldwork is a promising approach for filling critical information gaps. Our work contributes to the Aichi Biodiversity Targets and emphasizes the need for signatory nations to the Convention on Biological Diversity to respond to these information gaps. Given our findings, we hope to stimulate the formulation of clear plans to systematically document ethnobotanical knowledge in northwestern South America and elsewhere before it vanishes.

  14. Early Tertiary plate reconstructions for the South China Sea region: constraints from northwest Borneo

    NASA Astrophysics Data System (ADS)

    Gower, Robert J. W.

    Previous plate reconstructions and tectonic syntheses for the southeast Asia region (Leichti et al. 1960, Ben Avraham and Uyeda 1973, Hamilton 1979, Holloway 1982, Taylor and Hayes 1982) have all highlighted the problems of correlating events in northwest Borneo with contemporaneous extension of the South China Sea. Theoretical modelling of crustal scale deformation in Asia during the Tertiary (Tapponnier et al. 1982) following India's collision with Asia suggested that the opening of the South China Sea basin accommodated major sinistral displacement. Haile (1973) and Hamilton (1979) have proposed that active subduction of oceanic crust beneath northwestern Borneo during the late Cretaceous and early Tertiary was associated with the development of a major arcuate accretionary complex, the "Crocker-Rajang" complex (Haile 1973), which is exposed over a large area of West Malaysia. Contemporaneous outer arc basin sedimentation in west Sarawak and eastern Kalimantan is consistent with a southeasterly dipping orientation of subduction at the margin. The duration of subduction is poorly constrained, but the initiation of major clastic depocenter in the Baram-Belait area during the early Miocene (Brondjik 1963), indicates a major change in sedimentation and deformational style at the northwestern Bornea continental margin. Pre-Miocene geological and paleomagnetic evidence from Borneo is inconsistent with the simple model of estrusion tectonics and suggests that Borneo and Malaya were separate microplates during the early Tertiary.

  15. Freshwater fish faunas, habitats and conservation challenges in the Caribbean river basins of north-western South America.

    PubMed

    Jiménez-Segura, L F; Galvis-Vergara, G; Cala-Cala, P; García-Alzate, C A; López-Casas, S; Ríos-Pulgarín, M I; Arango, G A; Mancera-Rodríguez, N J; Gutiérrez-Bonilla, F; Álvarez-León, R

    2016-07-01

    The remarkable fish diversity in the Caribbean rivers of north-western South America evolved under the influences of the dramatic environmental changes of neogene northern South America, including the Quechua Orogeny and Pleistocene climate oscillations. Although this region is not the richest in South America, endemism is very high. Fish assemblage structure is unique to each of the four aquatic systems identified (rivers, streams, floodplain lakes and reservoirs) and community dynamics are highly synchronized with the mono-modal or bi-modal flooding pulse of the rainy seasons. The highly seasonal multispecies fishery is based on migratory species. Freshwater fish conservation is a challenge for Colombian environmental institutions because the Caribbean trans-Andean basins are the focus of the economic development of Colombian society, so management measures must be directed to protect aquatic habitat and their connectivity. These two management strategies are the only way for helping fish species conservation and sustainable fisheries.

  16. Diverse nodule bacteria were associated with Astragalus species in arid region of northwestern China.

    PubMed

    Chen, Weimin; Sun, Liangliang; Lu, Jianjun; Bi, Liangliang; Wang, Entao; Wei, Gehong

    2015-01-01

    The legume species of Astragalus as traditional Chinese medicine source and environmental protection plants showed an extensive distribution in the arid region of northwestern China. However, few rhizobia associating with Astragalus have been investigated in this region so far. In this study, 78 endophytic bacteria were isolated from root nodules of 12 Astragalus species and characterized by the PCR-RFLP of 16S rRNA gene and symbiotic genes together with the phylogenetic analysis. Results showed that the majority (53%) of isolates are non-nodulating Agrobacterium sp. and the rest are Mesorhizobium genomic species (41%), Ensifer spp. and Rhizobium gallicum (6%), respectively. Mesorhizobium genomic species are broadly distributed in the Astragalus symbioses and most of them share similar symbiotic genes. It seems that horizontal gene transfer occurred frequently among different genomic species independent of their original hosts and sites. Astragalus adsurgens is nodulated by a widely range of rhizobial species in the nodulation test, revealing that it could play an important role in diversification of Astragalus symbionts and that might be a reason for its wide adaptation to diverse environments. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. An assessment of restoration success to forests planted for ecosystem restoration in loess plateau, Northwestern China.

    PubMed

    Yang, Zhanbiao; Jin, Hongxi; Wang, Gang

    2010-05-01

    Using ecosystem attributes identified by the Society of Ecological Restoration International, we assessed three restoration projects in the loess plateau, northwestern China, including planting Larix principis-rupprechtii (LS) and Pinus tabulaeformis (PS) on shrubland, and planting L. principis-rupprechtii on open forest land (LO). The reestablishment of native species in LS and PS was poorer than LO because of the excessive stand density. Species diversity, seedling number, and seedling diversity were significantly higher in LO than in LS and PS. Soil nutrient was also significantly higher in the LO treatment. The vegetation composition, species diversity, and soil nutrient in LO, however, were more similar to these in the reference. Our results indicate that planting L. principis-rupprechtii on open forest land had accelerated the succession of the ecosystem for approximately 30 years. But the poor natural regeneration of L. principis-rupprechtii suggests that post-planting activities in LO are required after timber harvesting or the natural mortality of the L. principis-rupprechtii. Management operation such as selective thinning will be required in LS and PS to promote the true restoration of native species diversity in the future.

  18. Migration and cutoff of meanders in the hyperarid environment of the middle Tarim River, northwestern China

    NASA Astrophysics Data System (ADS)

    Li, Zhiwei; Yu, Guo-An; Brierley, Gary John; Wang, Zhaoyin; Jia, Yanhong

    2017-01-01

    A meandering channel has developed in the middle Tarim River, the longest inland river flowing through a hyperarid environment in northwestern China. Although the drainage basin of the Tarim River extends over 1 million km2, flow in downstream reaches is largely restricted to summer months, and irrigation pressures have made the flood season increasingly short. The planform morphology, lateral migration rate, and cutoffs of 105 meanders were analysed using multiperiod remote sensing images and field survey analyses of channel bed and bank properties and of riparian vegetation cover. Results show that planform attributes of the meandering Tarim River are similar to those found in other environments. The ratio of the channel centreline length to the neck channel width of meanders ranges between 1.2 and 8.1, the bend curvature (ratio of bend radius to channel width) ranges between 0.30 and 2.8, and the average deflection angle of the bend apexes is 79.9°. Meander migration rates range from 1.4 to 96.7 m y- 1. From 2000 to 2013, 45 cutoffs occurred along the 400-km-long reach. As the riparian vegetation cover is sparse because of limited precipitation and because banks are comprised of dense roots, fine sand and silt materials, but lack clay, bank strength is limited and presents limited constraints upon bend movement.

  19. Correction to the crustal thickness of the northwestern China using the data of seismic tomography

    NASA Astrophysics Data System (ADS)

    Xu, Ping; Fu, Rong-Shan; Huang, Jian-Ping; Dai, Zhi-Yang; Zha, Xian-Jie

    2005-11-01

    Considering the influence of the density anomaly of the crust and upper mantle on the gravity, we provide a new arithmetic to invert the crustal thickness. Applying the result of seismic tomography, we calculated the lateral density heterogeneity of the crust and upper mantle and the gravity anomalies caused by such lateral density heterogeneity, and then subtracted gravity anomalies caused by mentioned density anomalies from observational Bouguer anomalies, finally in view of the correction on the initial crustal thickness based on the hypothesis of isostasy, inverted the regional crustal thickness. Using the data of seismic tomography from XU et al, we inverted the Moho depth beneath northwestern China. It is shown that the gravity anomalies on the surface of the earth are -6×10-4 m/s2-×10-4 m/s2. Compared with the result inverted directly using Bouguer anomalies, this method can bring correction of 6 km to the Moho depth. And this method make it further mature in theory and feasible in practice to invert the thickness of the crust using data of grarity and provide a new arithmetic for us to understand the conformation of the Moho.

  20. Effects of cloudiness on carbon dioxide exchange over an irrigated maize cropland in northwestern China

    NASA Astrophysics Data System (ADS)

    Zhang, B. C.; Cao, J. J.; Bai, Y. F.; Yang, S. J.; Hu, L.; Ning, Z. G.

    2011-02-01

    Clouds can strongly influence solar radiation and affects other microclimatic factors (such as air temperature and vapour pressure deficit), and those changed environmental conditions may exert strong effects on carbon exchange between terrestrial ecosystems and the atmosphere. In this study, we analyzed how canopy photosynthesis and ecosystem respiration respond to changes in cloudy conditions, based on two years of eddy-covariance and meteorological data from an irrigated maize cropland in Yingke oasis of northwestern China. The results showed that net carbon uptake was more negative under cloudy than under clear conditions, it indicates that net carbon uptake increased under cloudy days. The rate of ecosystem respiration (Re) decreased under cloudy conditions due to decreased air temperature. However, photosynthesis was suppressed by the decreasing air temperature and vapour pressure deficit (VPD) under cloudy skies. Thus, the enhancement of net carbon uptake under cloudy skies mainly contributed from increasing photosynthesis with diffuse radiation. Those results improve our understanding of the effects of cloud cover on carbon exchange process in maize (C4) cropland, and improve our understanding of the driver improving net carbon uptake under cloudy conditions.

  1. Climate-driven speedup of alpine treeline forest growth in the Tianshan Mountains, Northwestern China.

    PubMed

    Qi, Zhaohuan; Liu, Hongyan; Wu, Xiuchen; Hao, Qian

    2015-02-01

    Forest growth is sensitive to interannual climatic change in the alpine treeline ecotone (ATE). Whether the alpine treeline ecotone shares a similar pattern of forest growth with lower elevational closed forest belt (CFB) under changing climate remains unclear. Here, we reported an unprecedented acceleration of Picea schrenkiana forest growth since 1960s in the ATE of Tianshan Mountains, northwestern China by a stand-total sampling along six altitudinal transects with three plots in each transect: one from the ATE between the treeline and the forest line, and the other two from the CFB. All the sampled P. schrenkiana forest patches show a higher growth speed after 1960 and, comparatively, forest growth in the CFB has sped up much slower than that in the ATE. The speedup of forest growth at the ATE is mainly accounted for by climate factors, with increasing temperature suggested to be the primary driver. Stronger water deficit as well as more competition within the CFB might have restricted forest growth there more than that within the ATE, implying biotic factors were also significant for the accelerated forest growth in the ATE, which should be excluded from simulations and predictions of warming-induced treeline dynamics.

  2. Microchemical Study of Pigments and Binders in Polychrome Relics from Maiji Mountain Grottoes in Northwestern China.

    PubMed

    Liu, Luyao; Shen, Wei; Zhang, Bingjian; Ma, Qian

    2016-08-01

    In this study, an integrated analytical method was developed to investigate the composition of both the inorganic pigments and organic binders of polychrome relics in Maiji Mountain Grottoes in northwestern China. Cross-sections of each sample were prepared at the beginning of the study, and all experiments were carried out on these cross-sections. Polychromic structures were revealed by optical microscopy and scanning electron microscopy-backscattered electron imaging. Inorganic materials were determined by using SEM coupled with an energy dispersive spectrometer and μ-Raman spectrometer, whereas organic materials were identified by staining techniques and highly sensitive and specific immunofluorescence microscopy. Data showed that the red colors are attributed to one or two pigments of red ochre, cinnabar, and minium; the blue pigment is natural lazurite; the green pigment is ascribed to atacamite; the white color is attributed to potassium feldspar; and the black surface is formed by the discoloration of minium to plattnerite under the influence of environmental factors. Regarding organic binders used in painting and preparation layers, mammalian animal glue and chicken egg white were both found alone or in mixture. Finally, the conclusion is made that the Secco technique is employed in polychrome relics from Maiji Mountain Grottoes.

  3. High prevalence of Eimeria infection in dairy goats in Shaanxi province, northwestern China.

    PubMed

    Zhao, Guang Hui; Lei, Li-Hui; Shang, Chuan-Chuan; Gao, Man; Zhao, Yan Qing; Chen, Chao-Xi; Chen, De-Kun

    2012-06-01

    A survey of dairy goats for infection with Eimeria species of coccidia was conducted in the Shaanxi province, northwestern China between December and November 2010, including Saanen and Guanzhong breeds. A total of 584 fecal samples (250 and 334 from Saanen and Guanzhong dairy goats, respectively) in six farms were collected. Eimeria oocysts were seen in 568 (97.3%) fecal samples, with six species, namely Eimeria jolchijevi, Eimeria arloingi, Eimeria alijevi, Eimeria caprina, Eimeria hirci, and Eimeria christenseni. The most prevalent were E. arloingi in Saanen and Guanzhong dairy goats, with an overall prevalence of 83.3% and 84.4%, and the lowest prevalence were E. christenseni (26.9%) and E. hirci (20.7%) for Saanen and Guanzhong Dairy goats, respectively. Two or more Eimeria species were commonly presented in all the age groups; 80.0% and 81.4% of positive Saanen and Guanzhong dairy goats carried more than two species, and 1.6% and 6.5% of two breeds had six species. The results of the present survey suggested that Eimeria infection is wide and severe in the Saanen and Guanzhong dairy goats, which suggested that integrated strategies should be implemented to prevent and control coccidial infection in dairy goats in this province.

  4. Ecohydrological factors affecting nitrate concentrations in a phreatic desert aquifer in northwestern China

    USGS Publications Warehouse

    Gates, J.B.; Böhlke, J.K.; Edmunds, W.M.

    2008-01-01

    Aerobic conditions in desert aquifers commonly allow high nitrate (NO 3-) concentrations in recharge to persist for long periods of time, an important consideration for N-cycling and water quality. In this study, stable isotopes of NO3- (??15N NO3 and ??18ONO3) were used to trace NO3- cycling processes which affect concentrations in groundwater and unsaturated zone moisture in the arid Badain Jaran Oesert in northwestern China. Most groundwater NO3- appears to be depleted relative to Cl- in rainfall concentrated by evapotranspiration, indicating net N losses. Unsaturated zone NO 3- is generally higher than groundwater NO 3- in terms of both concentration (up to 15 476 ??M, corresponding to 3.6 mg NO3--N per kg sediment) and ratios with Cl-. Isotopic data indicate that the NO3- derives primarily from nitrification, with a minor direct contribution of atmospheric NO3- inferred for some samples, particularly in the unsaturated zone. Localized denitrification in the saturated zone is suggested by isotopic and geochemical indicators in some areas. Anthropogenic inputs appear to be minimal, and variability is attributed to environmental factors. In comparison to other arid regions, the sparseness of vegetation in the study area appears to play an important role in moderating unsaturated zone NO3- accumulation by allowing solute flushing and deterring extensive N2 fixation. ?? 2008 American Chemical Society.

  5. Shear wave anisotropy in northwestern South America and its link to the Caribbean and Nazca subduction geodynamics

    NASA Astrophysics Data System (ADS)

    Idárraga-García, J.; Kendall, J.-M.; Vargas, C. A.

    2016-09-01

    To investigate the subduction dynamics in northwestern South America, we measured SKS and slab-related local S splitting at 38 seismic stations. Comparison between the delay times of both phases shows that most of the SKS splitting is due to entrained mantle flow beneath the subducting Nazca and Caribbean slabs. On the other hand, the fast polarizations of local S-waves are consistently aligned with regional faults, which implies the existence of a lithosphere-confined anisotropy in the overriding plate, and that the mantle wedge is not contributing significantly to the splitting. Also, we identified a clear change in SKS fast directions at the trace of the Caldas Tear (˜5°N), which represents a variation in the subduction style. To the north of ˜5°N, fast directions are consistently parallel to the flat subduction of the Caribbean plate-Panama arc beneath South America, while to the south fast polarizations are subparallel to the Nazca-South America subduction direction. A new change in the SKS splitting pattern is detected at ˜2.8°N, which is related to another variation in the subduction geometry marked by the presence of a lithosphere-scale tearing structure, named here as Malpelo Tear; in this region, NE-SW-oriented SKS fast directions are consistent with the general dip direction of the underthrusting of the Carnegie Ridge beneath South America. Further inland, this NE-SW-trending mantle flow continues beneath the Eastern Cordillera of Colombia and Merida Andes of Venezuela. Finally, our results suggest that the subslab mantle flow in northwestern South America is strongly controlled by the presence of lithospheric tearing structures.

  6. Three Disputes and Three Objectives: China and the South China Sea

    DTIC Science & Technology

    2011-01-01

    South China Sea began when China pressured Vietnam and several oil companies in connection with oil exploration and drilling off the Vietnamese coasts...summer of 2007, China told a number of U.S. and for- eign oil and gas firms to stop exploration work with Vietnamese partners in the South China Sea...major challenge now confronting our nation? It is the question of resources.”50 Zhou Shouwei, vice president of the China National Offshore Oil

  7. A retreating fan-delta system in the Northwestern Junggar Basin, northwestern China-Characteristics, evolution and controlling factors

    NASA Astrophysics Data System (ADS)

    Jia, Haibo; Ji, Hancheng; Li, Xinwei; Zhou, Hang; Wang, Linsheng; Gao, Yan

    2016-06-01

    In this study, we use seismic reflection, logging and core data to investigate the depositional systems and their controlling factors in the lower Triassic in the northwestern margin of Junggar basin. The succession shows strong lateral and vertical facies variation. The facies associations indicate the development of conglomeratic fan-delta system, with characteristics of fining-upward and landward migration of facies belts. A critical balance between progradation, aggradation, and retrogradation controlled the evolution of delta successions within an overall transgressive regime. Migration of the locus of active faulting exerted the primary control on fan-delta thickness. Variations on the sandy component and gravel type within the fan-delta system among different units indicate the control of provenance. The climate significantly influenced the mode of sediment transfer from the feeder system to the basin. The significant climate change from arid to humid played a primary role in controlling the fan-delta architecture. Our study suggests that in tectonic-active basin, the controls of tectonics on the sequence stratigraphy are still fundamental. However, during the tectonic quiescence or rift-depression transition stage, significant changes of climate would play a primary role in controlling the sediment dispersal. The current study reveals that the hydrocarbon reservoir shows a landward migration trend within a retreating fan-delta system.

  8. Open Ocean Internal Waves, South China Sea

    NASA Technical Reports Server (NTRS)

    1989-01-01

    These open ocean internal waves were seen in the south China Sea (19.5N, 114.5E). These sets of internal waves most likely coincide with tidal periods about 12 hours apart. The wave length (distance from crest to crest) varies between 1.5 and 5.0 miles and the crest lengths stretch across and beyond this photo for over 75 miles. At lower right, the surface waves are moving at a 30% angle to the internal waves, with parallel low level clouds.

  9. Quantifying the Intra-Regional Precipitation Variability in Northwestern China over the Past 1,400 Years

    PubMed Central

    Lee, Harry F.; Pei, Qing; Zhang, David D.; Choi, Kan P. K.

    2015-01-01

    There has been a surge of paleo-climatic/environmental studies of Northwestern China (NW China), a region characterized by a diverse assortment of hydro-climatic systems. Their common approach, however, focuses on “deducing regional resemblance” rather than “exploring regional variance.” To date, efforts to produce a quantitative assessment of long-term intra-regional precipitation variability (IRPV) in NW China has been inadequate. In the present study, we base on historical flood/drought records to compile a decadal IRPV index for NW China spanned AD580–1979 and to find its major determinants via wavelet analysis. Results show that our IRPV index captures the footprints of internal hydro-climatic disparity in NW China. In addition, we find distinct ~120–200 year periodicities in the IRPV index over the Little Ice Age, which are attributable to the change of hydro-climatic influence of ocean-atmospheric modes during the period. Also, we offer statistical evidence of El Niño Southern Oscillation (Indo-Pacific warm pool sea surface temperature and China-wide land surface temperature) as the prominent multi-decadal to centennial (centennial to multi-centennial) determinant of the IRPV in NW China. The present study contributes to the quantitative validation of the long-term IRPV in NW China and its driving forces, covering the periods with and without instrumental records. It may help to comprehend the complex hydro-climatic regimes in the region. PMID:26154711

  10. Quantifying the Intra-Regional Precipitation Variability in Northwestern China over the Past 1,400 Years.

    PubMed

    Lee, Harry F; Pei, Qing; Zhang, David D; Choi, Kan P K

    2015-01-01

    There has been a surge of paleo-climatic/environmental studies of Northwestern China (NW China), a region characterized by a diverse assortment of hydro-climatic systems. Their common approach, however, focuses on "deducing regional resemblance" rather than "exploring regional variance." To date, efforts to produce a quantitative assessment of long-term intra-regional precipitation variability (IRPV) in NW China has been inadequate. In the present study, we base on historical flood/drought records to compile a decadal IRPV index for NW China spanned AD580-1979 and to find its major determinants via wavelet analysis. Results show that our IRPV index captures the footprints of internal hydro-climatic disparity in NW China. In addition, we find distinct ~120-200 year periodicities in the IRPV index over the Little Ice Age, which are attributable to the change of hydro-climatic influence of ocean-atmospheric modes during the period. Also, we offer statistical evidence of El Niño Southern Oscillation (Indo-Pacific warm pool sea surface temperature and China-wide land surface temperature) as the prominent multi-decadal to centennial (centennial to multi-centennial) determinant of the IRPV in NW China. The present study contributes to the quantitative validation of the long-term IRPV in NW China and its driving forces, covering the periods with and without instrumental records. It may help to comprehend the complex hydro-climatic regimes in the region.

  11. Mapping Water Use Efficiency for the Xinjiang Province in Northwestern China

    NASA Astrophysics Data System (ADS)

    Veroustraete, F.; Verstraeten, W.; Li, Q.; Dong, Q.; van Roey, T.

    2007-12-01

    The Tarim river basin, one of the basins integrated in the UNESCO - HELP Programme, is located in the Xinjiang Autonomous Region in Northwestern China. It is one of the world's largest closed hydrological drainage systems, and has ideal soils for agriculture, if enough water is available. Farmers in the province produce one- sixth of China's total cotton production. Since the 1950's however, excessive land reclamation, over-grazing and increased utilization of water resources in the upper reaches of the basin intensified environmental degradation. This impacted on cattle stock reduction (by water shortage), withered poplars and vegetation, along the lower reaches of the basin. Riparian forest degraded with a reduction in its area of 200 000 ha in total. Higher water use combined with a gradual mean yearly temperature increase due to climate change caused serious hydrological problems in the basin. Since the 1970's a strong drying out of the lower region is elicited. This phenomenon degraded the basin's downstream ecosystems, with an expansion of desertification as a consequence. Quite conspicuously, the Tarim river has shortened by 320 km, onward the period mentioned above. In the lower region of the basin, the situation is very serious. It can in fact be described as an ecological disaster, with dying trees and vegetation, the drying out of rivers and as consequence a regression of the river fish population as well as increased salt deposits. In the ARCHIMOD bilateral project between Belgium and China, important objectives are the description of the phenomena cited above using hydraulic modelling for some sub-basins of the Tarim as well as the application of remote sensing to estimate evapotranspiration (ETR), soil moisture content (SMC) and water use efficiency (WUE) at the scale of the Xinjiang province. Te estimate WUE at this scale the carbon exchange model C-Fix was applied. Our paper focusses on the application of remote sensing to map WUE for the Xinjiang

  12. Analyzing the Effects of Dust on Atmospheric Composition over Northwestern China in Spring 2008 Using WRF-Chem

    NASA Astrophysics Data System (ADS)

    Wang, J.; Allen, D. J.; Pickering, K. E.; Li, Z.

    2014-12-01

    Adjacent to the Taklimakan and Gobi deserts, northwestern China experiences dust storms frequently during the spring season. With the population and industry in northwestern China growing rapidly, anthropogenic pollution also impacts the aerosol composition and therefore optical properties and radiative effects. For instance, NOx emissions from Gansu province increased from ~195 Gg/yr in 2000 to ~323 Gg/yr in 2006 due to the fast growth of transportation vehicles, while SO2 emissions dropped from ~439 Gg/yr to ~338 Gg/yr because flue-gas desulfurization (FGD) devices are widely used in coal-fired powerplants. The WRF-Chem model with CBMZ chemistry mechanism, MOSAIC 8-bins aerosol module and GOCART dust emission algorithm, is applied to simulate the processes responsible for temporal changes in the aerosol distribution, aerosol optical properties and size distribution in Northwestern China due to the impact of dust and anthropogenic emissions during spring 2008, a time period during which an intensive field campaign was conducted at the Zhangye National Climate Observatory (39.082°N, 100.276°E, 1460 m above sea level) of the China Meteorological Administration. This field campaign provided observations of meteorological fields, radiative fluxes, trace gases concentrations, aerosol optical properties, and aerosol size distributions to evaluate the model simulation. The observational data showed a pronounced diurnal variation of trace gases and aerosols: low in the afternoon and high in the morning. Elevated pollutant levels were observed in several dust storms during this campaign. We will investigate the atmospheric processes that are responsible for the atmospheric composition, and assess the relative impact of dust and anthropogenic emissions on local air quality.

  13. Early Cambrian ocean anoxia in South China.

    PubMed

    Jiang, Shao-Yong; Pi, Dao-Hui; Heubeck, Christoph; Frimmel, Hartwig; Liu, Yu-Ping; Deng, Hai-Lin; Ling, Hong-Fei; Yang, Jing-Hong

    2009-06-11

    The cause of the most marked changes in the evolution of life, which define the first-order stratigraphic boundary between the Precambrian and the Phanerozoic eon, remains enigmatic and a highly topical subject of debate. A global ocean anoxic event, triggered by large-scale hydrogen sulphide (H(2)S) release to surface waters, has been suggested by Wille et al., on the basis of two data sets from South China and Oman, to explain the fundamental biological changes across the Precambrian/Cambrian (PC/C) boundary. Here we report a new precise SHRIMP U-Pb zircon age of 532.3 +/- 0.7 million years (Myr) ago (Fig. 1) for a volcanic ash bed in the critical unit that reflects the ocean anoxic event, the lowermost black shale sequence of the Niutitang Formation in the Guizhou Province, South China. This age is significantly younger than the precise PC/C boundary age of 542.0 +/- 0.3 Myr ago, approximately 10 Myr younger than the extinction of the Ediacaran fauna, and thus challenging the view of a major ocean anoxic event having been responsible for the major changes in the direction of evolution at the PC/C boundary.

  14. A numerical study of the South China Sea Warm Current during winter monsoon relaxation

    NASA Astrophysics Data System (ADS)

    Zhang, Cong; Ding, Yang; Bao, Xianwen; Bi, Congcong; Li, Ruixiang; Zhang, Cunjie; Shen, Biao; Wan, Kai

    2017-06-01

    Using a Finite-Volume Community Ocean Model, we investigated the dynamic mechanism of the South China Sea Warm Current (SCSWC) in the northern South China Sea (NSCS) during winter monsoon relaxation. The model reproduces the mean surface circulation of the NSCS during winter, while model-simulated subtidal currents generally capture its current pattern. The model shows that the current over the continental shelf is generally southwestward, under a strong winter monsoon condition, but a northeastward counter-wind current usually develops between 50- and 100-m isobaths, when the monsoon relaxes. Model experiments, focusing on the wind relaxation process, show that sea level is elevated in the northwestern South China Sea (SCS), related to the persistent northeasterly monsoon. Following wind relaxation, a high sea level band builds up along the mid-shelf, and a northeastward current develops, having an obvious vertical barotropic structure. Momentum balance analysis indicates that an along-shelf pressure gradient provides the initial driving force for the SCSWC during the first few days following wind relaxation. The SCSWC subsequently reaches a steady quasi-geostrophic balance in the cross-shelf direction, mainly linked to sea level adjustment over the shelf. Lagrangian particle tracking experiments show that both the southwestward coastal current and slope current contribute to the northeastward movement of the SCSWC during winter monsoon relaxation.

  15. Winter precipitation change in South China in recent decades

    NASA Astrophysics Data System (ADS)

    Cai, Jingning

    2013-04-01

    Precipitation change is one of important climate researches in China, but winter precipitation variation in South China has not been studied so frequently. In China, it is rainy when hot; so summer precipitation is usually one focus in research, esp. in South China. However, winter precipitation and its change influence people profoundly in South China, also. The most recent example is what happened over South China in winter 2008. In this winter, millions of people suffered from the unusual cold and snowy winter. It led to huge loss in economy and traffic as well. Roads closed and railway stations were jammed and crowded with people; many planes were grounded for heavy snow and bad weather. Transmission lines faulted in the mountains. The ommunication signals were affected. Everyday food supply including vegetables and meats had to be delayed or interrupted. In some city even water supply was interrupted. And garbage in the city was piled up. Just in this winter the snow depth and coverage area in many places in South China broke or equaled the historical records. In fact, it isn't the only one unusual winter precipitation event in South China. Since 1950s, several freezing and snowy winters struck the South in China. In this research, winter precipitation change in recent years in South China has been discussed based on the precipitation observations. The associated large scale atmospheric circulation change is also analyzed. It is found that snowy winter in South China hardly comes in most periods of 2000s, but in recent decades this heavy snow in winter has appeared several times as observations shows. This phenomenon could be related to the large scale atmospheric circulation change.

  16. The South China Sea: Every Nation for Itself

    DTIC Science & Technology

    2013-05-23

    that the South China Sea holds between twenty-eight and two-hundred- thirteen billion barrels of oil (bbl.) underground. As a comparison, the United...its claim on historical records dating to the Han Dynasty (200BC) that reference use of the area by China along with literature of that other...South China Sea dispute through Olson’s theory, it became easy to see why the thirteen nations involved have failed to produce a solution. Most

  17. Pedogenesis and Permafrost Carbon Over the Eboling Ridge in Heihe River Basin, Northwestern China

    NASA Astrophysics Data System (ADS)

    Mu, C.; Zhang, T.; Cao, B.; Wang, Q.; Peng, X.; Cheng, G.

    2013-12-01

    Based on field permafrost sampling and laboratory analysis, we found that the average storages of soil organic carbon (SOC), total nitrogen (TN) and soil inorganic carbon (SIC) in permafrost soils were much more than that in the active layer on the Eboling Mountain in the upper reach of Heihe River basin, northwestern China. The objective of this study is to better understand the main soil physicochemical parameters influencing C and N dynamics in permafrost regions of northwestern China. Specifically, we investigated the effect of pedogenesis, cryogenic structure and SIC on SOC, TN and water-soluble organic carbon (WSOC) in the permafrost regions. The preliminary results show that SIC is a significant factor influencing carbon flux between atmosphere and terrestrial ecosystem and the distribution patterns of SOC and N. There are high correlation between SIC, SOC and N in permafrost. SOC and SIC can interact with each other, their small change may radically alter the carbon balance. SIC as a major factor will be crucial for developing large scale models evaluating C and N dynamics. High contents of C and N combined with a low vertical variability in each horizon on the Eboling Mountain can be explained by longer duration of pedogenesis and the influence of permafrost. In permafrost regions, the vertical distribution of soil C and N is also influenced by soil cryogenic structure. The high content of WSOC in deep permafrost soils can be explained by the formation of the ground ice causes the WSOC enrichment followed moisture migration. The average WSOC content in permafrost soils was larger than that in the active layer, suggesting that the labile carbon in permafrost soils has higher quality. SIC can reflect the microbial activity indirectly, due to the good negative relationship between SIC, soil pH and C/N ratios in permafrost. Soil pH values were the important factor influencing the distribution of SIC in deep permafrost soils. SIC in permafrost soils was

  18. South China Sea disputes: ASEAN’s Role in Addressing Disputes with China

    DTIC Science & Technology

    2013-12-13

    46 vi Salami-Slicing Strategy .............................................................................................48 Cabbage Strategy... cabbage strategies. Delaying Strategy China has applied the strategy of delaying a resolution for the disputes in the South China Sea for several...

  19. Prevention of US-China Armed Conflict Over South China Sea Territorial Disputes

    DTIC Science & Technology

    2013-03-01

    Amy Donahue and Bethany Danyluk, Energy Futures in Asia Final Report, Booz, Allen, Hamilton report sponsored by Director, Net Assessment, Office of...strong and growing 12 Alice D Ba, “Staking Claims and Making Waves in the South China Sea: How Troubled...of-parties-in-the-south-china-sea (accessed December 1, 2012). Ba, Alice D. “Staking Claims and Making Waves in the South China Sea: How Troubled

  20. Streamflow allocation in arid watersheds: a case study in Northwestern China

    NASA Astrophysics Data System (ADS)

    He, C.; Zhang, L.; Fu, L.; Luo, Y.; Li, L.; DeMarchi, C.

    2012-07-01

    This paper proposes a framework for allocating water resources among the upper, middle, and lower reaches of arid watersheds to meet the multiple demands for water, including rehabilitation of downstream ecosystem. The framework includes: (1) hydrologic simulation of distribution of water resources in the study watershed; (2) development of water allocation criteria; and (3) implementation of the water allocation plan. The advantages of the proposed framework are: (1) spatial integration; (2) multiple objectives; (3) incorporation of local needs through participatory decision making; and (4) dynamic evaluation. The framework was applied to the Heihe watershed, a large inland (terminal lake) watershed with a drainage area of over 128 000 km2 in Northwestern China. Simulation of the daily river flows for the period of 1990-2000 by the Distributed Large Basin Runoff Model shows that Qilian Mountain in the upper reach produced most of the runoff in the watershed, and the increased withdrawals of water for agricultural irrigation, industrial development, and municipal supplies at the middles reach oasis reduced the annual mean discharge by approximately 0.18 × 109 m3 over the simulation period, making the middle reach unable to deliver the mandated amount of 0.95 × 109 m3 water downstream by the State Council, under normal climatic conditions. Changes in land use practices need to be implemented to achieve the mandated water allocation plan. The paper suggests that a participatory watershed planning approach involving multiple stakeholders in the water allocation process be undertaken to address key questions regularly, including how much water should be allocated to what uses and for whom and at what price?

  1. Effects of Changing Cultivation System on Soil Carbon Dynamics in Cotton Field of Northwestern China

    NASA Astrophysics Data System (ADS)

    Li, Z.; Wang, X.; Tian, C.

    2010-12-01

    There has being a change in cotton cultivative practice in the northwestern China, i.e., from the traditional cultivation (TF) of no mulching with flood-irrigation to the modern cultivation (PM) of plastic film mulching with drip-irrigation. Little is known how this change affects soil carbon dynamics. This paper presents a field study that includes comparisons of soil organic carbon (SOC), soil CO2 concentration and soil surface CO2 efflux during cotton growing season. At the initial growing stage, SOC content was similar between TF and PM, showing a clear decreasing trend over depth (i.e., ~9 g/kg, ~7.5 g/kg and ~3 g/kg at 0-20 cm, 20-30 cm and 30-70 cm, respectively). After five months, SOC generally decreased at 0-20 cm but increased below 30 cm. Overal, SOC was higher in the surface soil in the PM than in the TF, particularly at 20-30 cm where SOC reached ~9 g/kg in the PM. In general, CO2 concentration in soil profile was higher in the PM (3107 - 9212 ppmv) than in the TF (1275 - 8994 ppmv). However, rate of CO2 efflux was lower in the PM than in the TF, primarily owing to plastic film covering. For the whole cotton growing season, accumulated rates of CO2 efflux were 300 g C m-2 and 394 g C m-2 in the PM and the TF, respectively. Fig. 1. Soil organic carbon (SOC) in (a) May (b) August and (c) October between plastic film mulching cultivation (PM) and traditional flooding cultivation (TF). Table 1. Soil surface CO2 efflux during different growing stages in different systems ADR: averaged daily rate during each stage; AE: accumulative efflux for each stage.

  2. Salt distribution under mulched drip irrigation in a cotton field of northwestern China

    NASA Astrophysics Data System (ADS)

    Zhang, Z.; Tian, F.; Hu, H.; Yao, X.; Zhong, R.; Hu, H.

    2012-12-01

    A 3-year experiment was conducted in Xinjiang, northwestern China, to investigate the specific pattern of salt distribution and accumulation associated with mulched drip irrigation in a cotton (Gossypium hirsutum L.) field. The experimental site was divided into three fields according to their distinct features of soil particle size distribution, and three replicators were designed in every field. Above 30,000 soil samples were collected throughout the experimental years, and this large number of soil samples help to answer the strong heterogeneity of soil salinity at the field scale and get the continuous salinity data under the destructive salinity measurement method. The results indicate that the soil salt migrates with water flux and accumulates at the periphery of the wetted soil mass, and the ration of the EC value in inter-film zone to wide-row zone at the end of growth period are 2.34, 1.78 and 1.24 for the three fields, respectively, which implies soil salt would transport to and accumulate in the inter film zone (IFM) more easily for sandy soil than clay soil along the horizontal direction. The field experiment shows the soil salt tends to build up at the interface of soil texture (where the soil texture changes rapidly from sandy at the upper layer to clay at the lower) , which means that layered pattern of soil particle size distribution dominates the vertical distribution pattern of soil salinity. The dimensionless index representing the specific salt distribution pattern associated with mulched drip irrigation was also introduced and modified, and the study shows that the index can well delineate the salt qualitative distribution along the vertical direction.

  3. High diversity of nitrogen-fixing bacteria in upper reaches of Heihe River, Northwestern China

    NASA Astrophysics Data System (ADS)

    Tai, X. S.; Mao, W. L.; Liu, G. X.; Chen, T.; Zhang, W.; Wu, X. K.; Long, H. Z.; Zhang, B. G.

    2013-03-01

    Vegetation plays a key role to water conservation in southern Qilian Mountains (Northwestern China), the upper reaches of Heihe River. Nitrogen-fixing bacteria are crucial for vegetation protection because they can supply plants with nitrogen source. Nevertheless, little is known about nitrogen-fixing bacteria in this region. In present study, nifH gene clone libraries were established for detecting the difference of nitrogen-fixing bacterial communities between Potentilla parvifolia shrub and Carex alrofusca meadow in the southern Qilian Mountains. All the identified nitrogen-fixing bacterial clones belonged to Proteobacteria. At the genus level, the Azospirillum sp. was only detected in shrub soil while Thiocapsa sp., Derxiasp., Ectothiorhodospira sp., Mesorhizobium sp., Klebsiella sp., Ensifer sp., Methylocella sp. and Peseudomonas sp. were just detected in meadow soil. Shannon-Wiener index of nifH gene ranged from 1.5 to 2.8 and was higher in meadow soil than shrub soil. Contrarily, the nifH gene copies and CFUs of cultured nitrogen-fixing bacteria ranged from 0.4 × 107 to 6.9 × 107 copies g-1 soil and 0.97 × 106 to 12.78 × 106 g-1 soil, respectively. Furthermore, both of them were lower in meadow soil than shrub soil. Statistical analysis revealed that diversity and copies of nifH gene mostly correlated with aboveground biomass in shrub soil. In meadow soil, nifH gene diversity was principally affected by altitude while copies did by soil available K.

  4. Environmental water chemistry and possible correlation with Kaschin-Beck Disease (KBD) in northwestern Sichuan, China.

    PubMed

    Shi, Zeming; Pan, Pujing; Feng, Yanwei; Kan, Zezhong; Li, Zhonghui; Wei, Fei

    2017-02-01

    During the past several decades, etiological and geochemical studies tend to link the Kaschin-Beck Disease (KBD) to the deficiency of some specific trace elements (e.g., selenium and iodine) in the environment; however the link has been proven inconclusive. In this work, we have investigated the relationship between KBD and the environment in a broader scope by examining comprehensively the chemistry of the surface waters in northwestern Sichuan, China, in relation to the KBD prevalence. The surface waters in the study area were found to be near neutral to slightly alkaline (pH6.70 to 8.85 with a mean of 7.91) and mostly soft (total hardness 35.2 to 314.3mg/L, mean 118.8mg/L) with low salinity (total dissolved solids (TDS) 44.5mg/L to 376.6mg/L, mean 146.6mg/L). The waters were dominated by cations Ca(2+) and Mg(2+) and anion HCO3(-); whereas the alkali metal ions K(+) and Na(+) and the anions Cl(-) and S04(2-) were relatively scarce. Spatially, the hardness/salinity of the surface waters exhibited a characteristic of being lower towards the center of the study area where most severe KBD endemic has been observed. Even though it is not conclusive at this stage, a correlation between KBD prevalence and the salinity/hardness of the surface waters of an area has been demonstrated. As a postulate, the long-term consumption of such low salinity waters may lead to a deficiency of some essential elements such as Ca, Mg, Se and I in humans, which may be a factor in inducing KBD. However, other factors such as high altitude and cold climate, poor nutrition and sanitary conditions may play an important role in the disease endemic.

  5. Risk of transmission of hepatitis B virus through childhood immunization in northwestern China.

    PubMed

    Murakami, Hitoshi; Kobayashi, Makoto; Zhu, Xu; Li, Yixing; Wakai, Susumu; Chiba, Yasuo

    2003-11-01

    Transmission of bloodborne pathogens by means of unsafe injection practices is a significant public health problem in developing countries. Although the overall proportion for immunization is low among injections, unsafe immunization practices affect mostly infants, a population with an increased likelihood of becoming hepatitis B virus carriers. This study estimated the prevalence of unsafe injection among vaccinators working at the peripheral level in northwestern China and the risk of HBV infections among infant vaccinees, and analyzed factors contributing to the most prevalent unsafe practice: the reuse of a non-sterilized reusable syringe among infants. A knowledge-attitude-practice survey was conducted in which 180 peripheral vaccinators selected by multi-stage cluster sampling in each of four provinces and one autonomous region completed a self-administered questionnaire. The lack of observational data for assessing the validity of the self-reported practices made the study prone to systematic respondent bias that may have skewed the results towards underestimation of unsafe practices. The minimum estimate of the percentage of peripheral vaccinators reusing a syringe and/or needle without sterilization between infants was 7.2-55.0%, whereas the percentage of those disposing of used disposable syringes and needles inappropriately was 8.9-23.3% by province. According to a model-based estimate, the annual number of HBV infections among 100,000 fully immunized children due to unsafe immunization injection was at least 135-3120. An insufficient supply of syringes and the attitude to justify reuse were significantly associated with the unsafe reuse of a reusable syringe in most part of the area studied. Introduction of auto-disable syringes may contribute to curb the unsafe practices, but the development of safe collection and disposal procedures for used syringes and needles is prerequisite. Sufficient supply of equipment as well as training, supervision, and

  6. Mid-Neolithic Exploitation of Mollusks in the Guanzhong Basin of Northwestern China: Preliminary Results

    PubMed Central

    Li, Fengjiang; Wu, Naiqin; Lu, Houyuan; Zhang, Jianping; Wang, Weilin; Ma, Mingzhi; Zhang, Xiaohu; Yang, Xiaoyan

    2013-01-01

    Mollusk remains are abundant in archaeological sites in the Guanzhong Basin of Northwestern China, providing good opportunities for investigations into the use of mollusks by prehistoric humans. Here we report on freshwater gastropod and bivalve mollusks covering the time interval from about 5600 to 4500 cal. yrs BP from sites of Mid-Late Neolithic age. They are identified as Cipangopaludina chinensis and Unio douglasiae, both of which are currently food for humans. The shells are well preserved and have no signs of abrasion. They are all freshwater gastropods and bivalves found in pits without water-reworked deposits and have modern representatives which can be observed in rivers, reservoirs, and paddy fields in the studied region. Mollusk shells were frequently recovered in association with mammal bones, lithic artifacts, and pottery. These lines of evidence indicate that the mollusks are the remains of prehistoric meals. The mollusk shells were likely discarded into the pits by prehistoric humans after the flesh was eaten. However, these mollusk remains may not have been staple food since they are not found in large quantities. Mollusk shell tools and ornaments are also observed. Shell tools include shell knives, shell reaphooks and arrowheads, whereas shell ornaments are composed of pendants and loops. All the shell tools and ornaments are made of bivalve mollusks and do not occur in large numbers. The finding of these freshwater mollusk remains supports the view that the middle Holocene climate in the Guanzhong Basin may have been warm and moist, which was probably favorable to freshwater mollusks growing and developing in the region. PMID:23544050

  7. Phylogenetic diversity of culturable bacteria from alpine permafrost in the Tianshan Mountains, northwestern China.

    PubMed

    Bai, Yu; Yang, Daqun; Wang, Jianhui; Xu, Shijian; Wang, Xiaoxiang; An, Lizhe

    2006-10-01

    Microbes have been discovered in permafrost sediments for nearly a century. However, microbiological analyses of alpine permafrost are very scarce. This study is a first attempt to describe the phylogenetic diversity of a culturable bacterial community isolated from alpine permafrost in the Tianshan Mountains in northwestern China. Aerobic 2.5-6.0x10(5) CFU/gdw (CFU per 1 gram of dry weight) on modified PYGV medium were recovered from alpine permafrost samples at 4 degrees C; among these, 91 bacterial isolates with different morphotypes were characterized by phenotypic properties, such as morphology, colony pigmentation, Gram staining, endospore formation and temperature range of growth. The isolates were further categorized based on amplified rDNA restriction analysis (ARDRA), and 51 representative isolates possessing distinct ARDRA patterns selected for subsequent 16S rDNA sequencing and phylogenetic analysis. The phylogenetic trees placed the 51 isolates in four major groups: the high-G+C Gram-positives, the low-G+C Gram-positives, Proteobacteria and the Cytophaga-Flavobacterium-Bacteroides (CFB) phylum. The most abundant and diverse isolates were members of Gram-positive bacteria, particularly the Arthrobacter as a dominant group in alpine permafrost culturable populations. Results of the Jukes-Cantor evolutionary distance matrix suggested that the vast majority of the isolates were different strains of known species, and three may represent new species within the genus Chryseobacterium of the CFB phylum. From this study, it is proposed that alpine permafrost sediments in the Tianshan Mountains provide a specific ecological niche for prolonging survival of diverse microbial lineages.

  8. The Sap Flow Dynamics and Response of Hedysarum scoparium to Environmental Factors in Semiarid Northwestern China

    PubMed Central

    Deng, Jifeng; Ding, Guodong; Gao, Guanglei; Wu, Bin; Zhang, Yuqing; Qin, Shugao; Fan, Wenhui

    2015-01-01

    Hedysarum scoparium is an important, fast-growing and drought-resistant shrub that has been extensively used for grassland restoration and preventing desertification in semiarid regions of northwestern China. The primary objective of this study was to investigate the diurnal and seasonal variations in stem sap flow (Js) and its relation to environmental factors. The stem heat balance method was applied to plants that were approximately 17 years old (with diameters of 25, 16, 13, and 9 mm at ground level and heights of 3.1, 1.8, 1.7 and 1.4 m) and growing under natural conditions. The vertical soil temperature profile (ST), soil surface heat flux (SoilG), volumetric soil moisture content (SWC) and meteorological variables such as solar radiation (Rn), air temperature (Ta), vapour pressure deficit (VPD), wind speed (Ws) relative humidity (RH) and precipitation (P) were simultaneously measured at a meteorological station on site. Results indicated that Js varied regularly during the diurnal and seasonal term. The nocturnal Js was substantial, with a seasonal variation similar to the patterns of daytime Js. The magnitude of Js changed considerably between sunny and rainy days. Redundancy (RDA) and Kendall’s tau analysis suggested that daily Js in large plants was more sensitive to environmental factors, and the variation in daily Js during the growing season could be described by a multiple linear regression against environmental variables including Ta, VPD, Ws, RH, ST, and SoilG. While the nocturnal Js in smaller plants was more sensitive to meteorological factors. Ta, VPD, and Ws were significantly correlated with nighttime Js. The hourly nighttime sap flow rate of H. scoparium corresponded closely to Ta and VPD following a non-linear pattern. The results of this study can be used to estimate the transpiration of H. scoparium. PMID:26136229

  9. The Sap Flow Dynamics and Response of Hedysarum scoparium to Environmental Factors in Semiarid Northwestern China.

    PubMed

    Deng, Jifeng; Ding, Guodong; Gao, Guanglei; Wu, Bin; Zhang, Yuqing; Qin, Shugao; Fan, Wenhui

    2015-01-01

    Hedysarum scoparium is an important, fast-growing and drought-resistant shrub that has been extensively used for grassland restoration and preventing desertification in semiarid regions of northwestern China. The primary objective of this study was to investigate the diurnal and seasonal variations in stem sap flow (Js) and its relation to environmental factors. The stem heat balance method was applied to plants that were approximately 17 years old (with diameters of 25, 16, 13, and 9 mm at ground level and heights of 3.1, 1.8, 1.7 and 1.4 m) and growing under natural conditions. The vertical soil temperature profile (ST), soil surface heat flux (SoilG), volumetric soil moisture content (SWC) and meteorological variables such as solar radiation (Rn), air temperature (Ta), vapour pressure deficit (VPD), wind speed (Ws) relative humidity (RH) and precipitation (P) were simultaneously measured at a meteorological station on site. Results indicated that Js varied regularly during the diurnal and seasonal term. The nocturnal Js was substantial, with a seasonal variation similar to the patterns of daytime Js. The magnitude of Js changed considerably between sunny and rainy days. Redundancy (RDA) and Kendall's tau analysis suggested that daily Js in large plants was more sensitive to environmental factors, and the variation in daily Js during the growing season could be described by a multiple linear regression against environmental variables including Ta, VPD, Ws, RH, ST, and SoilG. While the nocturnal Js in smaller plants was more sensitive to meteorological factors. Ta, VPD, and Ws were significantly correlated with nighttime Js. The hourly nighttime sap flow rate of H. scoparium corresponded closely to Ta and VPD following a non-linear pattern. The results of this study can be used to estimate the transpiration of H. scoparium.

  10. Distribution of ammonia oxidizers in relation to vegetation characteristics in the Qilian Mountains, northwestern China

    NASA Astrophysics Data System (ADS)

    Tai, X. S.; Mao, W. L.; Liu, G. X.; Chen, T.; Zhang, W.; Wu, X. K.; Long, H. Z.; Zhang, B. G.; Gao, T. P.

    2014-04-01

    Nitrogen is the major limiting nutrient in cold environments, and its availability is strongly dependent on nitrification. However, microbial communities driving this process remain largely uncharacterized in alpine meadow soils in northwestern China, namely those catalyzing the rate-limiting step of ammonia oxidation. In this study, ammonia-oxidizing communities in alpine meadow soils were characterized by real-time PCR and clone sequencing by targeting on amoA genes, which putatively encode ammonia monooxygenase subunit A. The results demonstrated that ammonia-oxidizing archaea (AOA) outnumbered ammonia-oxidizing bacteria (AOB) in the alpine meadow soils. Most of the AOA phylotypes detected in the study region fell within typical Group I.1b of Thaumarchaeota. Interestingly, a new ammonia-oxidizing archaeal group named "Kobresia meadow soil group" was found. Phylogenetic analysis of AOB communities exhibited a dominance of Nitrosospira-like sequences affiliated to beta-Proteobacteria. Compared with other alpine environments, Qilian Mountains had a great phylogenetic diversity of ammonia oxidizers. Principal Component Analysis (PCA) analysis showed that distinct AOA/AOB phylotype groups were attributed to different meadow types, reflecting an overall distribution of ammonia-oxidizing communities associated with meadow types. Redundancy Analysis (RDA) analysis showed that Axis 1 (90.9%) together with Axis 2 (9.1%) explained all the variables while Axis 1 exhibited a significant explanatory power. So that vegetation coverage mostly correlated to Axis 1 was the most powerful environmental factor in the study region. Characteristics of ammonia-oxidizing communities showed a close association with vegetation coverage.

  11. The origin and formation model of Permian dolostones on the northwestern margin of Junggar Basin, China

    NASA Astrophysics Data System (ADS)

    Lu, Xinchuan; Shi, Ji'an; Zhang, Shuncun; Zou, Niuniu; Sun, Guoqiang; Zhang, Shengyin

    2015-06-01

    This study investigates the mechanism of dolostone formation and establishes a dolomitization model in the Permian strata on the northwestern margin of Junggar Basin, China. Dolomitic rock samples are collected from the Permian Fengcheng Formation in Urho area and then characterized by petrological, mineralogical, carbon and oxygen isotope, and trace element geochemical analyses. Results show that the major types of dolomitic rocks include dolomitic mudstone, dolomitic siltstone, dolomitized tuffaceous siltstone, and dolomitized tuffaceous mudstone. The dolomitized rocks are dominated by euhedral or subhedral powder- and fine-crystal dolomites formed by replacement lacustrine argilla-calcareous and siliceous (tuffaceous) components and commonly filled with residual and late calcite cements. The parameters of dolomitic rocks show great variations, including the V/Ni ratio (1.02-4.88), Sr content (95.9-783.6 μg/g), Mg/Ca ratio (0.68-5.13), degree of ordering (0.39-1.00), δ18OPDB (-14.8‰ to 3.2‰), and δ13CPDB (-1‰ to 5.2‰). The dolomitic rocks have multi-stage origins and were formed in a semi-closed continental brackish-saltwater bay with weak hydrodynamic processes, deep water bodies, and relatively quiet conditions. In the Permian depositional stage, a combination of complex tectonic activities, fault development, hot subtropical climate, and frequent volcanic activities provided not only Mg2+ source for dolomitization but also channels for rapid flow and seepage of Mg-rich fluids. The origins of dolostones in the study area include penecontemporaneous dolomitization, burial dolomitization, and hydrothermal dolomitization. This study lays a foundation for further studies on dolomite formation and dolomite reservoir, and provides effective methods for researching complex dolostone (tuffaceous, shale and silty dolomite) formation.

  12. Structural and stratigraphic mapping from satellite imagery, Kalpin uplift, northwestern Tarim basin, northwest China

    SciTech Connect

    McKnight, C.L.; Carroll, A.R.; Chu, J.; Hendrix, M.S.; Graham, S.A.; Lyon, R.J.P. )

    1990-05-01

    The Kalpin uplift, located on the northwestern margin of the Tarim craton, northwest China, exposes a complete Paleozoic cratonal stratigraphic sequence. The lack of vegetative cover and the visible color contrasts between stratigraphic units afford an optimal situation for detailed geologic mapping from Landsat Multispectral Scanner imagery at a scale of 1:250,000. Field work in the eastern Kalpin uplift constrains the geologic interpretation of the satellite imagery. Exposed basement rock in the Kalpin uplift consists of deformed and metamorphosed upper Proterozoic strata cut by unmetamorphosed mafic dikes. The overlying sedimentary section was deposited primarily in shallow marine to nonmarine environments and includes Sinian (latest Proterozoic to early Cambrian) siliciclastics and carbonates; Cambrian and Ordovician carbonates; Silurian green shales; Devonian red beds; Carboniferous siliciclastics and carbonates; and Permian carbonates, siliciclastics, and subaerial basalt flows. Paleozoic strata are exposed in a series of low, parallel, curvilinear ranges located at the leading edges of low-angle, southeast-vergent thrust sheets. The regular thrust repetition of the entire Paleozoic section suggests the presence of a detachment horizon within the Cambrian section. These southeast-vergent thrust sheets override an older structural trend on the craton, the Bachu uplift, at right angles, folding as they do so. Strike-slip faults cutting the thrust sheets along the same trend as the Bachu uplift suggest the location of buried lateral ramps associated with the Bachu uplift. The young deformation in the Kalpin uplift is a response to compressive stresses produced by the northward movement of the Indian plate. Major faults in the Tian Shan mountain range to the north have been reactivated, resulting in southward-directed thrusting over the Tarim craton.

  13. Spatial distribution of an ancient agricultural oasis in Juyan, northwestern China

    NASA Astrophysics Data System (ADS)

    Hu, Ningke; Li, Xin

    2014-09-01

    Activities related to agricultural cultivation are some of the major human drivers of landscape change on the Earth's surface. Archaeological remains can provide qualitative evidence for studies of past agricultural development and environmental conditions. The ancient Juyan Oasis, which once flourished along the historic Silk Road, was a typical oasis of downstream inland river basins in the arid zone of northwestern China. Historical records and archaeological discoveries have qualitatively shown that the oasis supported extensive agricultural activities in this historical period from the Han Dynasty to the early Ming Dynasty (B.C. 202-A.D. 1375), which can be traced back to 2,000 years ago. In this study, different types of archaeological remains (including archaeological sites, ground surface artifacts, ancient cultivation ruins, and agricultural irrigation canals) that were obtained and identified from previous archaeological reports, field inspections, and remote sensing imagery were used to determine the spatial extent of the agricultural oasis in the historical period of interest. Our approach used multiple data sources in order to increase the accuracy and reliability of the results compared to previous studies. Our results distinctly suggested that much of the oasis was cultivated during the historical periods considered. Additionally, the arable land area in the historical period considered was roughly estimated to be approximately (3.39-4.75) × 104 ha. These findings regarding the spatial distribution of this ancient agricultural oasis and its arable land were reasonably determined to represent the ancient agricultural development that occurred in the Juyan Oasis better than results obtained from single sources of data.

  14. Molecular survey and characterization of a novel Anaplasma species closely related to Anaplasma capra in ticks, northwestern China.

    PubMed

    Yang, Jifei; Liu, Zhijie; Niu, Qingli; Liu, Junlong; Han, Rong; Liu, Guangyuan; Shi, Yaoxu; Luo, Jianxun; Yin, Hong

    2016-11-25

    Anaplasma spp. are tick-transmitted bacteria that infect a wide variety of wild and domestic animals. These pathogens exhibit a high degree of biological diversity, broad geographical distribution, and represent a serious threat to veterinary and public health worldwide. A novel Anaplasma species was identified in Haemaphysalis qinghaiensis (Ixodidae) in northwestern China and was molecularly characterized by comparison of 16S rRNA, gltA, and groEL gene sequences. Of the 414 samples tested, 24 (5.8%) were positive for this Anaplasma species. On the basis of the 16S rRNA gene, this organism has been found to be closely related to and exhibit the highest sequence similarity with A. capra (99.8-99.9%) that was identified in goats and humans in northern China, but was distinct from other known Anaplasma species. Sequence analysis of the gltA and groEL genes revealed that this Anaplasma species was distinct from A. capra considering the lower sequence identity (88.6-88.7% for gltA and 90.6-91.0% for groEL) and a divergent phylogenetic position. Therefore, we described this Anaplasma species as A. capra-like bacteria. The present study reports a potential novel Anaplasma species closely related to A. capra in H. qinghaiensis in northwestern China. The zoonotic potential of A. capra-like bacteria needs to be further determined.

  15. Anthropogenic Air Pollution Observed Near Dust Source Regions in Northwestern China During Springtime 2008

    NASA Technical Reports Server (NTRS)

    Li, Can; Tsay, Si-Chee; Fu, Joshua S.; Dickerson, Russell R.; Ji, Qiang; Bell, Shaun W.; Gao, Yang; Zhang, Wu; Huang, Jianping; Li, Zhanqing; Chen, Hongbin

    2010-01-01

    Trace gases and aerosols were measured in Zhangye (39.082degN, 100.276degE, 1460 m a.s. 1.), a rural site near the Gobi deserts in northwestern China during spring 2008. Primary trace gases (CO:265 ppb; SO2:3.4 ppb; NO(*y): 4.2 ppb; hereafter results given as means of hourly data) in the area were lower than in eastern China, but still indicative of marked anthropogenic emissions. Sizable aerosol mass concentration (153 micro-g/cu m) and light scattering (159/Mm at 500 nm) were largely attributable to dust emissions, and aerosol light absorption (10.3/Mm at 500 nm) was dominated by anthropogenic pollution. Distinct diurnal variations in meteorology and pollution were induced by the local valley terrain. Strong daytime northwest valley wind cleaned out pollution and was replaced by southeast mountain wind that allowed pollutants to build up overnight. In the afternoon, aerosols had single scattering albedo (SSA, 500 mn) of 0.95 and were mainly of supermicron particles, presumably dust, while at night smaller particles and SSA of 0.89-0.91 were related to Pollution. The diverse local emission sources were characterized: the CO/SO2, CO/NO(y), NO(y)/SO2 (by moles), and BC/CO (by mass) ratios for small point sources such as factories were 24.6-54.2, 25.8-35.9, 0.79-1.31, and 4.1-6.1 x 10(exp -3), respectively, compared to the corresponding inventory ratios of 43.7-71.9, 23.7-25.7, 1.84-2.79, and 3.4-4.0 x 10(exp -3) for the industrial sector in the area. The mixing between dust and pollution can be ubiquitous in this region. During a dust storm shown as an example, pollutants were observed to mix with dust, causing discernible changes in both SSA and aerosol size distribution. Further interaction between dust and pollutants during transport may modify the properties of dust particles that are critical for their large-scale impact on radiation, clouds, and global biogeochemical cycles.

  16. Anthropogenic air pollution observed near dust source regions in northwestern China during springtime 2008

    NASA Astrophysics Data System (ADS)

    Li, Can; Tsay, Si-Chee; Fu, Joshua S.; Dickerson, Russell R.; Ji, Qiang; Bell, Shaun W.; Gao, Yang; Zhang, Wu; Huang, Jianping; Li, Zhanqing; Chen, Hongbin

    2010-04-01

    Trace gases and aerosols were measured in Zhangye (39.082°N, 100.276°E, 1460 m a.s.l.), a rural site near the Gobi deserts in northwestern China during spring 2008. Primary trace gases (CO: 265 ppb; SO2: 3.4 ppb; NOy*: 4.2 ppb; hereafter results given as means of hourly data) in the area were lower than in eastern China, but still indicative of marked anthropogenic emissions. Sizable aerosol mass concentration (153 μg/m3) and light scattering (159 Mm-1 at 500 nm) were largely attributable to dust emissions, and aerosol light absorption (10.3 Mm-1 at 500 nm) was dominated by anthropogenic pollution. Distinct diurnal variations in meteorology and pollution were induced by the local valley terrain. Strong daytime northwest valley wind cleaned out pollution and was replaced by southeast mountain wind that allowed pollutants to build up overnight. In the afternoon, aerosols had single scattering albedo (SSA, 500 nm) of 0.95 and were mainly of supermicron particles, presumably dust, while at night smaller particles and SSA of 0.89-0.91 were related to pollution. The diverse local emission sources were characterized: the CO/SO2, CO/NOy, NOy/SO2 (by moles), and BC/CO (by mass) ratios for small point sources such as factories were 24.6-54.2, 25.8-35.9, 0.79-1.31, and 4.1-6.1 × 10-3, respectively, compared to the corresponding inventory ratios of 43.7-71.9, 23.7-25.7, 1.84-2.79, and 3.4-4.0 × 10-3 for the industrial sector in the area. The mixing between dust and pollution can be ubiquitous in this region. During a dust storm shown as an example, pollutants were observed to mix with dust, causing discernible changes in both SSA and aerosol size distribution. Further interaction between dust and pollutants during transport may modify the properties of dust particles that are critical for their large-scale impact on radiation, clouds, and global biogeochemical cycles.

  17. Linear trend and abrupt changes of climate indices in the arid region of northwestern China

    NASA Astrophysics Data System (ADS)

    Wang, Huaijun; Pan, Yingping; Chen, Yaning; Ye, Zhengwei

    2017-11-01

    In recent years, climate extreme events have caused increasing direct economic and social losses in the arid region of northwestern China. Based on daily temperature and precipitation data from 1960 to 2010, this paper discussed the linear trend and abrupt changes of climate indices. The general evolution was obtained by the empirical orthogonal function (EOF), the Mann-Kendall test, and the distribution-free cumulative sum chart (CUSUM) test. The results are as follows: (1) climate showed a warming trend at annual and seasonal scale, with all temperature indices exhibiting statistically significant changes. The warm indices have increased, with 1.37%days/decade of warm days (TX90p), 0.17 °C/decade of warmest days (TXx) and 1.97 days/decade of warm spell duration indicator (WSDI), respectively. The cold indices have decreased, with - 1.89%days/decade, 0.65 °C/decade and - 0.66 days/decade for cold nights (TN10p), coldest nights (TNn) and cold spell duration indicator (CSDI), respectively. The precipitation indices have also increased significantly, coupled with the changes of magnitude (max 1-day precipitation amount (RX1day)), frequency (rain day (R0.1)), and duration (consecutive dry days (CDD)). (2) Abrupt changes of the annual regional precipitation indices and the minimum temperature indices were observed around 1986, and that of the maximum temperature indices were observed in 1996. (3) The EOF1 indicated the overall coherent distribution for the whole study area, and its principal component (PC1) was also observed, showing a significant linear trend with an abrupt change, which were in accordance with the regional observation results. EOF2 and EOF3 show contrasts between the southern and northern study areas, and between the eastern and western study areas, respectively, whereas no significant tendency was observed for their PCs. Hence, the climate indices have changed significantly, with linear trends and abrupt changes noted for all climate indices

  18. A note on the South China Sea shallow interocean circulation

    NASA Astrophysics Data System (ADS)

    Fang, Guohong; Dwi, Susanto; Soesilo, Indroyono; Zheng, Quan'an; Qiao, Fangli; Wei, Zexun

    2005-11-01

    The existing estimates of the volume transport from the Pacific Ocean to the South China Sea are summarized, showing an annual mean westward transport, with the Taiwan Strait outflow subtracted, of 3.5±2.0 Sv (1 Sv=106 m3 s-1). Results of a global ocean circulation model show an annual mean transport of 3.9 Sv from the Pacific to the Indian Ocean through the South China Sea. The boreal winter transport is larger and exhibits a South China Sea branch of the Pacific-to-Indian Ocean throughflow, which originates from the western Philippine Sea toward the Indonesian Seas through the South China Sea, as well as through the Karimata and Mindoro Straits. The southwestward current near the continental slope of the northern South China Sea is shown to be a combination of this branch and the interior circulation gyre. This winter branch can be confirmed by trajectories of satellite-tracked drifters, which clearly show a flow from the Luzón Strait to the Karimata Strait in winter. In summer, the flow in the Karimata Strait is reversed. Numerical model results indicate that the Pacific water can enter the South China Sea and exit toward the Sulu Sea, but no observational evidence is available. The roles of the throughflow branch in the circulation, water properties and air-sea exchange of the South China Sea, and in enhancing and regulating the volume transport and reducing the heat transport of the Indonesian Throughflow, are discussed.

  19. Zooplankton Distribution in Tropical Reservoirs, South China

    NASA Astrophysics Data System (ADS)

    Lin, Qiu-Qi; Duan, Shun-Shan; Hu, Ren; Han, Bo-Ping

    2003-11-01

    The zooplankton of 18 reservoirs of South China was investigated in 2000. 61 Rotifera species, 23 Cladoceras and 14 Copepodas were identified. The most frequent Rotifera genera were Keratella, Brachionus, Trichocerca, Diurella, Ascomorpha, Polyarthra, Ploesoma, Asplanchna, Pompholyx and Conochilus. Bosmina longirostris, Bosminopsis deitersi, Diaphanosoma birgei, D. brachyurum and Moina micrura were typical of Cladocera in the reservoirs. Phyllodiaptomus tunguidus, Neodiaptomus schmackeri and Mesocyclops leuckarti were the most frequent Copepoda and M. leuckarti dominated Copepoda in most reservoirs. High zooplankton species richness with low abundance was characteristic of the throughflowing reservoir, whereas low species richness with low abundance was found in the reservoir with the longest retention time. Relative high abundance and medium species diversity were the distinction of intermediate retention time reservoirs.

  20. Seismological observations in Northwestern South America: Evidence for two subduction segments, contrasting crustal thicknesses and upper mantle flow

    NASA Astrophysics Data System (ADS)

    Yarce, Jefferson; Monsalve, Gaspar; Becker, Thorsten W.; Cardona, Agustín; Poveda, Esteban; Alvira, Daniel; Ordoñez-Carmona, Oswaldo

    2014-12-01

    The cause of tectonic deformation in northwestern South America and its link to upper mantle structure and flow are debated. We use a combination of broadband and short period travel time seismic data for P-waves to show that observations are consistent with the presence of two subduction segments in Colombia and contrasting values of crustal thickness. In Northern Colombia, at latitudes greater than 6°N, most of the seismic stations are associated with negative teleseismic travel time residuals, relative to a regional mean, suggesting that the upper mantle is seismically faster than predicted from global models. In particular, for the Caribbean coastal plains there are no signs of significant anomalies in the upper mantle, evidenced by the small magnitude of the travel time delays and subdued Pn speeds (~ 7.97 km/s). To the southeast of such plains there is an increase in magnitude of the negative travel time residuals, including the Northern Eastern Cordillera, the Perija Range and the Merida Andes. An analysis of non-isostatic residual topography, based on a model of crustal thickness in northwestern South America, is consistent with a slab-associated upper mantle flow beneath the region just east of the Bucaramanga Nest. We interpret these results to indicate the presence of a Caribbean slab, initially flat beneath the Caribbean coastal plains, and steepening sharply in the southeast, including the area of Bucaramanga. For most of the western Andean region and the Pacific coast, south of 6°N, teleseismic differential travel time residuals are predominantly positive, indicating that the upper mantle is in general seismically slower than the reference model. Beneath the Central Cordillera, just to the east of this area, the residuals become smaller and predominantly negative; residual non-isostatic topography is negative as well. These features are probably related to the effect of the Nazca subduction developing an asthenospheric wedge.

  1. How does the South Asian High influence extreme precipitation over eastern China?

    NASA Astrophysics Data System (ADS)

    Ning, Liang; Liu, Jian; Wang, Bin

    2017-04-01

    Based on the high-resolution observed daily precipitation data, three characteristic regions over eastern China are first defined through the rotated empirical orthogonal function. Then, the relationship between summer (June-July-August) extreme precipitation across the three characteristic regions of eastern China and the South Asian High (SAH) is examined to determine how the northwest-southeast movement and area (magnitude) of SAH influence the summer extreme precipitation across eastern China. When the South Asian High is located anomalously northwest, there is more extreme precipitation over the northern part of eastern China but less extreme precipitation over the Jiang-Huai River Basin. When the SAH intensifies, there is more extreme precipitation over the Jiang-Huai River Basin. The mechanisms are that under the conditions of anomalously northwestward displacements, the positive geopotential anomalies over central Asia induce a deep barotropic Korean High through a Rossby wave train, resulting in more water vapor transportation to eastern China with more convergence over the northern part of eastern China located at the northwestern edge of the Korean High but with a divergence over the Jiang-Huai River Basin. When the SAH intensifies, accompanied by an enhanced and westward extended western Pacific subtropical High, the convergence over the Jiang-Huai River Basin increases with enhanced water vapor transportation due to the confluence of warm and cold advections. These mechanisms are achieved through shifts toward the high tail (low tail) of the daily precipitation cumulative distributions of these two regions and finally increases (decreases) in the occurrence of extreme precipitation.

  2. Green auctions and reduction of information rents in payments for environmental services: an experimental investigation in Sunan County, northwestern China.

    PubMed

    Deng, Xiaohong; Xu, Zhongmin

    2015-01-01

    Reducing information rents is an important task for government agencies wishing to purchase maximal environmental services with limited budgets. This paper reports on several green auction options for reducing information rents and improving the performance of the "Grain for Green" Payments for environmental services (PES) program implemented in northwestern China. In r experimental auctions and investigations, door-to-door interviews were conducted and bidding envelopes and survey questionnaires were used to determine the offers and the foregone profits of the participants. Three scenarios are analyzed in this paper: a uniform price auction, a discriminatory price auction, and an opportunity-cost system. The results show that compared to the uniform price auction system, the other auction systems can increase the cost-effectiveness of conservation contracting. Competitive bidding can reveal true opportunity costs and can reduce information rents extracted from the government by farmers using private information. The demographics and average bids of these auction types were also analyzed. "Perfect information" in the opportunity-cost offer system has the best performance but is very hard to implement in reality. The results of this research show that the auction is a valuable tool for purchasing conservation contracts in northwestern China, but that in the future, the performance of these auctions should be studied with relaxed model assumptions.

  3. Divergent Population Genetic Structure of the Endangered Helianthemum (Cistaceae) and Its Implication to Conservation in Northwestern China.

    PubMed

    Su, Zhihao; Richardson, Bryce A; Zhuo, Li; Jiang, Xiaolong

    2016-01-01

    Population genetic studies provide a foundation for conservation planning, especially for endangered species. Three chloroplast SSRs (mtrnSf-trnGr, mtrnL2-trnF, and mtrnL5-trnL3) and the internal transcribed spacer were used to examine the population structure of Helianthemum in northwestern China. A total of 15 populations of the genus were collected. Nine chloroplast haplotypes and two nuclear genotypes were detected. Both the nuclear and chloroplast data showed two lineages in Helianthemum songaricum, respectively, distributed in Yili Valley and western Ordos Plateau. A total of 66.81% (p < 0.001) of the genetic variation was supported by this lineage split. A Mantel test showed a significant correlation between genetic distance and geographical distance (r = 0.937, p < 0.001). Based on genetic analyses, cpSSRs data support strong genetic divergence between regions. We speculate that the climate change during the late Tertiary and early Quaternary isolated H. songaricum into their current distribution, resulting in interruption of gene flow, leading to isolation and genetic divergence between the two regions. Meanwhile, possible selfing would increase genetic drift in small fragmented populations, that might account for the observed genetic divergence in both regions. Given the loss of genetic diversity and genetic divergence in small populations of Helianthemum in northwestern China immediate conservation management steps should be taken on the species.

  4. Green Auctions and Reduction of Information Rents in Payments for Environmental Services: An Experimental Investigation in Sunan County, Northwestern China

    PubMed Central

    Deng, Xiaohong; Xu, Zhongmin

    2015-01-01

    Reducing information rents is an important task for government agencies wishing to purchase maximal environmental services with limited budgets. This paper reports on several green auction options for reducing information rents and improving the performance of the “Grain for Green” Payments for environmental services (PES) program implemented in northwestern China. In r experimental auctions and investigations, door-to-door interviews were conducted and bidding envelopes and survey questionnaires were used to determine the offers and the foregone profits of the participants. Three scenarios are analyzed in this paper: a uniform price auction, a discriminatory price auction, and an opportunity-cost system. The results show that compared to the uniform price auction system, the other auction systems can increase the cost-effectiveness of conservation contracting. Competitive bidding can reveal true opportunity costs and can reduce information rents extracted from the government by farmers using private information. The demographics and average bids of these auction types were also analyzed. “Perfect information” in the opportunity-cost offer system has the best performance but is very hard to implement in reality. The results of this research show that the auction is a valuable tool for purchasing conservation contracts in northwestern China, but that in the future, the performance of these auctions should be studied with relaxed model assumptions. PMID:25793263

  5. Divergent Population Genetic Structure of the Endangered Helianthemum (Cistaceae) and Its Implication to Conservation in Northwestern China

    PubMed Central

    Su, Zhihao; Richardson, Bryce A.; Zhuo, Li; Jiang, Xiaolong

    2017-01-01

    Population genetic studies provide a foundation for conservation planning, especially for endangered species. Three chloroplast SSRs (mtrnSf-trnGr, mtrnL2-trnF, and mtrnL5-trnL3) and the internal transcribed spacer were used to examine the population structure of Helianthemum in northwestern China. A total of 15 populations of the genus were collected. Nine chloroplast haplotypes and two nuclear genotypes were detected. Both the nuclear and chloroplast data showed two lineages in Helianthemum songaricum, respectively, distributed in Yili Valley and western Ordos Plateau. A total of 66.81% (p < 0.001) of the genetic variation was supported by this lineage split. A Mantel test showed a significant correlation between genetic distance and geographical distance (r = 0.937, p < 0.001). Based on genetic analyses, cpSSRs data support strong genetic divergence between regions. We speculate that the climate change during the late Tertiary and early Quaternary isolated H. songaricum into their current distribution, resulting in interruption of gene flow, leading to isolation and genetic divergence between the two regions. Meanwhile, possible selfing would increase genetic drift in small fragmented populations, that might account for the observed genetic divergence in both regions. Given the loss of genetic diversity and genetic divergence in small populations of Helianthemum in northwestern China immediate conservation management steps should be taken on the species. PMID:28105040

  6. A comprehensive classification of anomalous circulation patterns responsible for persistent precipitation extremes in South China

    NASA Astrophysics Data System (ADS)

    Wu, Hui; Zhai, Panmao; Chen, Yang

    2016-06-01

    Based on observational precipitation at 63 stations in South China and NCEP-NCAR reanalysis data during 1951-2010, a cluster analysis is performed to classify large-scale circulation patterns responsible for persistent precipitation extremes (PPEs) that are independent of the influence of tropical cyclones (TCs). Conceptual schematics depicting configurations among planetary-scale systems at different levels are established for each type. The PPEs free from TCs account for 38.6% of total events, and they tend to occur during April-August and October, with the highest frequency observed in June. Corresponding circulation patterns during June-August can be mainly categorized into two types, i.e., summer-I type and summer-II type. In summer-I type, the South Asian high takes the form of a zonal-belt type. The axis of upstream westerly jets is northwest-oriented. At the middle level, the westerly jets at midlatitudes extend zonally. Along the southern edge of the westerly jet, synoptic eddies steer cold air to penetrate southward; the Bay of Bengal (BOB) trough is located to the north; a shallow trough resides over coastal areas of western South China; and an intensified western Pacific subtropical high (WPSH) extends westward. The anomalous moisture is mainly contributed by horizontal advection via southwesterlies around 20 °N and southeasterlies from the southern flange of the WPSH. Moisture convergence maximizes in coastal regions of eastern South China, which is the very place recording extreme precipitation. In summer-II type, the South Asian high behaves as a western-center type. The BOB trough is much deeper, accompanied by a cyclone to its north; and a lower-level trough appears in northwestern parts of South China. Different to summer-I type, moisture transport via southwesterlies is mostly responsible for the anomalous moisture in this type. The moisture convergence zones cover Guangdong, Guangxi, and Hainan, matching well with the areas of flooding. It is

  7. Characterization of Methicillin-Resistant and -Susceptible Staphylococcal Isolates from Bovine Milk in Northwestern China

    PubMed Central

    Li, Longping; Zhou, Luoxiong; Wang, Lihong; Xue, Huping; Zhao, Xin

    2015-01-01

    Emergence of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-resistant coagulase-negative staphylococci (MR-CoNS) in bovine milk is a major public health concern. The primary purpose of this research was to determine molecular genetic characteristics and antibiotic resistance of staphylococcal isolates recovered from milk of mastitic cows in the Shaanxi Province in Northwestern China. One hundred and thirteen methicillin-susceptible Staphylococcus aureus (MSSA), one mecA-positive and phenotype-positive MRSA, seven mecA- and mecC- negative but phenotype-positive MRSA and two MR-CoNS including one oxacillin-susceptible mecA-positive Staphylococcus haemolyticus (OS-MRSH) and one mecA-positive and methicillin-resistant Staphylococcus epidermidis (MRSE) isolates were recovered from 214 quarter milk samples on 4 dairy farms. All above 123 isolates were subjected to antibiotic resistance profiling. S. aureus isolates were also genotyped using the spa typing and the multilocus sequence typing (MLST). Eight MRSA and 2 MR-CoNS isolates were additionally tested for SCCmec types. Resistance was common among isolates against ampicillin or penicillin (80.5%), kanamycin (68.3%), gentamicin (67.5%), tetracycline (43.9%) and chloramphenicol (30.1%). However, no isolate was resistant to vancomycin or teicoplanin. Twenty, 29 and 58 isolates showed resistance to 1, 2 or more than 2 antibiotics, respectively. The predominant multidrug resistance profile was penicillin/ampicillin/kanamycin/gentamicin/tetracycline (46 isolates). Most S. aureus isolates belonged to spa types t524 (n = 63), t11772 (a new type, n = 31) and t4207 (n = 15). At the same time, MLST types ST71 (n = 67) and ST2738 (a new type, n = 45) were identified as dominant sequence types. The mecA-positive and phenotype-positive MRSA isolate had a composite genotype t524-ST71-SCCmecIVa, while 7 mecA-negative but phenotype-positive MRSA isolates were all t524-ST71. The OS-MRSH isolate contained a type V

  8. Reconstructing the role of South China in Pangea and earlier supercontinents

    NASA Astrophysics Data System (ADS)

    Cawood, Peter; Zhao, Guochun; Yao, Jinlong; Wang, Wei; Xu, Yajun; Wang, Yuejun

    2017-04-01

    The history of the South China Craton and the constituent Yangtze and Cathaysia blocks is directly linked to Earth's Phanerozoic and Precambrian record of supercontinent assembly and dispersal. Exposed Archean rocks are limited to isolated fragments in the Yangtze Block and preserve a record of Meso- to Neo-Archean igneous activity, sedimentation and metamorphism associated with a period of global craton formation and stabilization that corresponds with assembly of the Kenor supercontinent/supercraton. However, there is insufficient data to link its history with other similar aged cratons. The tectonostratigraphic record in South China in the Paleoproterozoic, corresponding with assembly of Nuna, suggests that rock units in the Yangtze Block were spatially linked with northwestern Laurentia and possibly Siberia, whereas Cathaysia was joined to northern India. From the formation of Rodinia at the end of the Mesoproterozoic through to that of Pangea in the mid-Paleozoic, Cathaysia remained joined to northern India. Early Neoproterozoic supra-subduction zone magmatic arc-back arc assemblages ranging in age from 1000 Ma to 810 Ma occur within Cathaysia, along its northwestern margin, and along the southeastern margin of the Yangtze Block. These rocks provide a record of convergent plate interaction along the periphery of Rodinia, which continued along the western margin of the Yangtze Block until around 700 Ma and correlates with similar along strike subduction zone magmatism in northwest India, Seychelles and Madagascar. During final assembly of Gondwana in the early Paleozoic suturing of India-South China with the Western Australia-Mawson blocks along the Kuunga Orogen resulted in the accretion of the Sanya Block of Hainan Island with the rest of Cathaysia. The accretion of Laurussia to Gondwana in the mid-Paleozoic to form Pangea corresponds with the initiation of lithospheric extension along the northern margin of Gondwana and the separation of a number of

  9. Geodynamics of the South China Sea

    NASA Astrophysics Data System (ADS)

    Sibuet, Jean-Claude; Yeh, Yi-Ching; Lee, Chao-Shing

    2016-12-01

    The beginning of seafloor spreading in the South China Sea (SCS) is now established from IODP drilling Leg 349 at 33 Ma. Chron 12 (32 Ma) is the oldest chron identified in the SCS. The nature of the crust of the northeastern part of the SCS located north of chron C12, where chrons 15 to 17 were previously identified, is not oceanic but thinned continental crust intruded by volcanic elongated features emplaced 17-22 Ma ago. Based on magnetic anomaly identifications, the end of the SCS spreading could be either 15.5, 20.5 Ma (Briais et al., 1993; Barckhausen et al., 2014) or something else. However, as post-spreading magmatic activity ( 13-3.5 Ma) largely masks the spreading fabric in particular near the axis of the east sub-basin, published locations of the axial magnetic anomaly (extinct spreading axis) and spreading rates are not reliable. A contoured map of the extremely dense set of magnetic data shows that a few magnetic lineations belonging to the magnetic seafloor spreading fabric are still preserved and parallel to the N055° bathymetric seafloor spreading trends identified on swath-bathymetric maps in the central part of the SCS, suggesting that the extinct ridge axis is N055° trending with potential N145° transform faults. Based on published swath-bathymetric data, oceanic domains with different seafloor spreading lineaments have been delimited (N055°, N075° and N085°) and provide important constraints used to propose a kinematic sketch of the SCS opening. As a consequence, the Zhongnan faults zone, located between the east and southeast sub-basins, acted as a major fracture zone system during the SCS opening, with horizontal offsets varying from 50 km to 140 km. The flow-line pattern defined from the seafloor spreading lineaments and the few identified FZs have been used to highlight conjugate segments of continental margins. During the first phases of opening of the SCS, from the fit of continents to chron C10 (30 Ma), the N175° extension observed

  10. Recent Seismic Experiments of OBS in the South China Sea

    NASA Astrophysics Data System (ADS)

    Ruan, A.; Li, J.; Wu, Z.

    2012-12-01

    Since 2006 some research institutions of China have carried out some important seismic experiments by using ocean bottom seismometer(OBS) in the South China Sea (SCS) and obtained many concrete progresses in modeling the crustal structure of SCS and also in understanding of its formation and evolution as well. In 2006 three wide-angle profiles were completed in the northern margin, named OBS2006-1 across the northwestern sub-basin, OBS2006-2 parallel to the sea basin boundary and OBS2006-3 across the Dongsha Rise and Chaoshan Depression respectively. In 2010 two wide- angle profiles were completed, named OBS2010-1 and OBS 2010-2 both perpendicular to the northern off-shore faulting system. During 2009-2011 four wide-angle profiles were completed in the southern margin, named OBS973-1 from southern margin to the southwestern sub-basin, OBS973-2 from Liyue Bank to the southwestern sub-basin and OBS973-3 from Xisha to the southwestern sub-basin, OBS2011-2 from Xisha to Hainan Island respectively. In 2011 two 3D seismic array of OBS were completed in the Zhongnan-Changlong sea mount chain and Huangyan-Zhenbei sea mount chain respectively. Here we present some primary but important results as follows. (1) The velocity model of OBS2006-1 indicates that the crust under the continental slope decreases from 21km to 11km, and to 7.7km in the northwestern sub-basin with Moho depth ascends from 21km to 11km. The tectonic geometry and velocity structure of the northwestern sub-basin and its margins on both sides shows symmetrical and conjugate and indicates pure shear mode of continental margin rifting mechanism. (2) The velocity model of OBS2006-3 reveals remarkable thickness with maximum 8 km of the Mesozoic sediment in Chaoshan Depression in which velocity increases downward from 4.4 km/s at top to 5.3 km/s at the bottom. The buried depth of Moho decreases from 24-25 km under Dongsha Rise to 17 km in the lower slope and an obviously velocity abnormal is detected in the upper

  11. Selected hydrologic data, Yampa River basin and parts of the White River basin, northwestern Colorado and south-central Wyoming

    USGS Publications Warehouse

    Giles, T.F.; Brogden, Robert E.

    1978-01-01

    Selected hydrologic data are presented from four energy-related projects conducted by the U.S. Geological Survey in the Yampa River basin and parts of the White River basin in northwestern Colorado and south-central Wyoming. Water-quality data during 1974 and 1975 and parts of 1976 for 129 ground-water sites and 119 surface-water sites are tabulated. For most samples, major cations, anions, and trace metals were analyzed. For the same time period, field measurements of specific conductance, temperature, and pH were made on 252 springs and wells. These samplings sites, as well as the locations of 20 climatological stations, 18 snow-course sites, and 43 surface-water gaging stations, are shown on maps. Geologic units that contain coal deposits or supply much of the water used for stock and domestic purposes in the area also are shown on a map. (Woodard-USGS)

  12. Carbon disulfide measurements in the atmosphere of the western North Atlantic and the northwestern South Atlantic Oceans

    NASA Technical Reports Server (NTRS)

    Bandy, Alan R.; Thornton, Donald C.; Johnson, James E.

    1993-01-01

    Carbon disulfide (CS2) measurements were made over the western and equatorial North Atlantic Ocean and the northwestern and equatorial South Atlantic Ocean. Carbon disulfide was in the range 0.4-50 pptrv in the atmosphere of the western North Atlantic Ocean. Emissions from anthropogenic sources and wet lands were found to be important although anthropogenic sources were 4-6 times larger than biogenic sources. The flux of CS2 from eastern North America between 30 and 39 deg latitude was estimated to be 2 x 10(exp 8)g/yr or sulfur. The anthropogenic contribution was 1.8 x 10(exp 8)g/yr of sulfur whereas the contribution of marshes was 0.2 x 10(exp 8)g/yr of sulfur. Sources of CS2 at high latitudes in the northern hemisphere were comparatively weak. Carbon disulfide levels in the western South Atlantic Ocean between -5 and 1 deg latitude were in the range 0.2-6 pptrv. Most of the CS2 appeared to come from biomass burning in Africa. Carbon disulfide was much higher close to shore suggesting that the South American continent was a significant source although too few data were available to quantify it. On ferry lights from Wallops, Virginia to Natal, Brazil, CS2 levels at the ferry altitude of about 6 km averaged 1.2 pptrv. This background CS2 was adequate to account for all the carbonyl sulfide (OCS) in the atmosphere.

  13. Community composition of picoeukaryotes in the South China Sea during winter

    NASA Astrophysics Data System (ADS)

    Lin, Yun-Chi; Chiang, Kuo-Ping; Kang, Lee-Kuo

    2017-07-01

    Picoeukaryotes, the smallest protists, are highly diverse and abundant in the ocean. However, little information is available about their community composition in the tropical northwestern Pacific Ocean. This study collected surface and deep chlorophyll maximum (DCM) waters from the South China Sea (SCS) to study the picoeukaryotic composition by constructing clone libraries of the 18S rRNA gene. The libraries were dominated by the heterotrophic organisms, alveolates and Rhizaria, which accounted for 46% and 16% of total clones, respectively. MALV-I was the most abundant group in alveolates, and Rhizaria appears to be a key organism in the SCS, particularly within DCM layers. These results indicate that parasitism is significant in the oligotrophic and tropical SCS. Apart from core-dinoflagellates, chlorophytes, haptophytes, cryptophytes and pelagophytes were other important contributors to primary production in pico-sized fraction based on quantitative and qualitative data.

  14. Microfacies and platform characteristic of the Ordovician in the northwestern Tarim Basin, NW China

    NASA Astrophysics Data System (ADS)

    Hu, Xiaolan; Li, Bo; Chen, Xiaozhi; Hong, Keyan; Jiang, Shenglin; Zhu, Liangliang; Wang, Di

    2017-06-01

    The Ordovician deposition is characterized by a thick carbonate in the Tarim Basin. In northwestern section of the basin, rocks are chiefly deposited in a carbonate ramp. Twelve microfacies have been distinguished on the basis of their depositional textures and petrographic analysis. Four depositional belts such as tidal flat, lagoon, shoal and open marine can be identified.

  15. Source apportionment of VOCs and their impacts on surface ozone in an industry city of Baoji, Northwestern China.

    PubMed

    Xue, Yonggang; Ho, Steven Sai Hang; Huang, Yu; Li, Bowei; Wang, Liqin; Dai, Wenting; Cao, Junji; Lee, Shuncheng

    2017-08-30

    Level of surface ozone (O3) has been increasing continuously in China in recent years, while its contributors and formation pathways are less understood. In this study, distributions of volatile organic compounds (VOCs) and the roles on O3 pollution have been investigated in a typical industrial city of Baoji in Northwestern China by means of monitoring of their concentrations and other trace gases. The air samples have been collected at three sites according to urban function area. Concentration of VOCs in Weibin site, which near to industrial zone, was higher than most of other cities in China, and the ambient VOCs were dominated by aromatics and alkenes. The temporal variations of VOCs and O3 coincided with the surface wind, implying that the formation of O3 was impacted by both exports of plumes upwind and local photochemical reactions. Result of source apportionment indicated that industrial emission, vehicular exhaust, and solvent evaporation were three major pollution origins. Alkenes and aromatics contributed to the largest fractions of photochemical reactivity, suggesting the strong influences from industrial and traffic sectors. The study presents the characteristic VOCs and other factors in the contribution of O3 formation in China.

  16. Deep Circulation in the South China Sea

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaolong; Zhao, Wei; Xu, Xiaobiao; Tian, Jiwei; Zhou, Chun

    2016-04-01

    The South China Sea (SCS) is the largest marginal sea of the northwest Pacific. The deep circulation in the SCS is investigated on the basis of the Hybrid Coordinate Ocean Model (HYCOM). All the experiments show reasonable agreement with observation from mooring arrays. Analysis of these results provides a detailed spatial structure and temporal variability of the deep circulation in the SCS. The major features of the SCS deep circulation are basin-scale cyclonic gyre and concentrated deep western boundary current (DWBC). The transport of the DWBC is ~2 Sv at 16.5°N with a width of ~53 km. As flowing southwestward, the DWBC becomes weaker with a wider range. Deep upwelling in the SCS is estimated of 0.19 to 1.15 m d-1 with the strongest area around the DWBC. The model results reveal the existence of 80 to 120 days oscillation in the deep northeastern circulation and the DWBC, which are also the areas with large eddy kinetic energy. This seasonal oscillation is northwestward with a velocity amplitude of ~1.0~1.5 cm s-1. The distribution of mixing parameters in the deep SCS plays a role in both spatial structure and volume transport of the deep circulation. Compared with the north shelf of the SCS with the Luzon Strait, deep circulation in the SCS is more sensitive to the large vertical mixing parameters of the Zhongsha Island Chain area.

  17. Nitrogen Flow Analysis in Huizhou, South China

    NASA Astrophysics Data System (ADS)

    Ma, Xiaobo; Wang, Zhaoyin; Yin, Zegao; Koenig, Albert

    2008-03-01

    Eutrophication due to uncontrolled discharges of nitrogen and phosphorus has become a serious pollution problem in many Chinese rivers. This article analyzes the nitrogen flow in Huizhou City in the East River watershed in south China. The material accounting method was applied to investigate the nitrogen flows related to human activities, which consist of the natural and anthropogenic systems. In Huizhou City, the nonpoint source pollution was quantified by the export coefficient method and the domestic discharge was estimated as the product of per capita nitrogen contribution and population. This research was conducted based on statistical information and field data from 1998 in the Huizhou City. The results indicated that the major nitrogen flows in this area were river loads, fertilizer and feedstuff imports, atmospheric deposition, animal manure volatilization, and processes related to burning and other emissions. In 1998, about 40% of the nitrogen was retained in the system and could result in potential environmental problems. Nitrogen export was mainly by rivers, which account for about 57% of the total nitrogen exported. Comparisons made between the East River and the Danube and Yangtze Rivers show that the unit area nitrogen export was of the same magnitude and the per capita nitrogen export was comparable.

  18. Metamorphic evolution and geochronology of the Dunhuang orogenic belt in the Hongliuxia area, northwestern China

    NASA Astrophysics Data System (ADS)

    Wang, Hao Y. C.; Wang, Juan; Wang, Guo-Dong; Lu, Jun-Sheng; Chen, Hong-Xu; Peng, Tao; Zhang, Hui C. G.; Zhang, Qian W. L.; Xiao, Wen-Jiao; Hou, Quan-Lin; Yan, Quan-Ren; Zhang, Qing; Wu, Chun-Ming

    2017-03-01

    Garnet-bearing mafic granulites and amphibolites from the Hongliuxia area of the southern Dunhuang orogenic belt, northwestern China, commonly occur as lenses or boudinages enclosed within metapelite or marble, which represent the block-in-matrix feature typical of orogenic mélange. Three to four generations of metamorphic mineral assemblages are preserved in these rocks. In the high-pressure amphibolites, prograde mineral assemblages (M1) occur as inclusions (hornblende + plagioclase + quartz ± chlorite ± epidote ± ilmenite) preserved within garnet porphyroblasts, and formed at 550-590 °C and 7.7-9.2 kbar based on geothermobarometry. The metamorphic peak mineral assemblages (M2) are composed of garnet + hornblende + plagioclase + quartz + clinopyroxene, as well as titanite + zircon + rutile + apatite as accessory minerals in the matrix, and are estimated to have formed at 640-720 °C and 14.1-16.0 kbar. The first retrograde assemblages (M3) are characterized by "white-eye socket" symplectites (hornblende + plagioclase + quartz ± biotite ± epidote ± magnetite) rimming garnet porphyroblasts, which formed at the expense of the garnet rims and adjacent matrix minerals during the decompression stage under P-T conditions of 610-630 °C and 5.6-11.8 kbar. The second retrograde assemblages (M4) are intergrowths of actinolite and worm-like quartz produced by the breakdown of the matrix hornblendes, and formed under P-T conditions of ∼490 °C and ∼2.8 kbar. For the high-pressure mafic granulites, the prograde assemblages (M1) are represented by plagioclase + quartz preserved within the garnet porphyroblasts. The metamorphic peak assemblages (M2) are garnet + matrix minerals (clinopyroxene + plagioclase + quartz + hornblende + rutile + zircon) and were estimated to have formed at ∼680 °C and ∼15.4 kbar. The retrograde assemblages (M3) are characterized by fine-grained patches of hornblende + plagioclase + quartz rimming the garnet porphyroblasts, as well as

  19. Tectonics of South China: Key to understanding West Pacific geology

    NASA Astrophysics Data System (ADS)

    Hsü, Kenneth J.; Li, Jiliang; Chen, Haihong; Wang, Qingchen; Sun, Shu; Şengör, A. M. C.

    1990-11-01

    South China is not a post-Caledonian platform, but a composite of orogenic belts. This late Proterozoic/Mesozoic orogen is a collage of three continental fragments. The three blocks are Yangzi, Huanan, and Dongnanya, and they are separated by the Banxi-Nanpanjiang (formerly Xianggangzhe) and Gunanhai Suture zones. Yangzi was separated from Gondwanaland during Late Precambrian when an open ocean, called Banxi, was present between the two continents. Tectonic processes at an active margin during Sinian and Early Paleozoic time led to the genesis of an accretionary wedge complex, the Banxi Melange and the Huanan Flysch Nappes, on the northern margin of Huanan, which was then the northern margin of the Gondwana Continent. Reorganization of plates during the Devonian suspended subduction at the Huanan active margin. Huanan was uplifted and unconformably overlain by transgressive deposits of Devonian and/or Carboniferous age. A remnant ocean, the Nanpanjiang Sea, still existed between Yangzi and Huanan, and deep-water sedimentation continued both at the southern margin of Yangzi and at the northwestern margin of Huanan. The latter again became an active margin during Late Paleozoic, when Permian and Triassic flysch sediments were deposited in foredeeps ahead of advancing nappes. Huanan and Yangzi collided during the Triassic, and resulted in the deformation of the passive margin of the latter to form the Yangzi Deformed Belt. Huanan was separated from a more southerly continent, Dongnanya, in the Devonian by seafloor spreading which created a Late Paleozoic and early Mesozoic ocean (Gunanhai Ocean). A continuously deposited sequence, ranging in age from Devonian to Triassic, was laid down on the southern passive margin of Huanan. On the other side of the ocean, the Dongnanya Permian strata include glacial marine deposits of Gondwanaland affinity. Dongnanya became separated from Gondwanaland during the Late Permian, when it marched northward to be reunited with Huanan

  20. O3, SO2, NO2, and UVB measurements in Beijing and Baseline Station of northwestern part of China

    NASA Technical Reports Server (NTRS)

    Guo, Song; Zhou, Xiuji; Zhang, Xiachun

    1994-01-01

    A MKII Brewer ozone spectrometer was used in Beijing from Oct. 1990 to June 1991 to measure O3, SO2 and UVB radiation. And since Nov. 1991 a new MKIV Brewer spectrometer, which can take the measurements of O3, SO2, NO2 and UVB radiation, has been set up in Beijing. The MKII Brewer spectrometer was moved to Qinghai baseline station which is on the Qinghai-tibetean plateau in the northwestern part of China. Both the data in Beijing and Qinghai baseline station has been analyzed and some results will be shown here along with the ozone profiles botained through the Umkehr program given by AES of Canada for the Brewer ozone spectrometer.

  1. Numerical simulation of the impact of reforestation on winter meteorology and environment in a semi-arid urban valley, Northwestern China.

    PubMed

    Yu, Ye; He, Jianjun; Zhao, Suping; Liu, Na; Chen, Jinbei; Mao, Hongjun; Wu, Lin

    2016-11-01

    Since 1999 Chinese government has made great effort to reforest the south and north mountains surrounding urban Lanzhou - a city located in a river valley, Northwestern China. Until 2009 obvious land use change occurred, with 69.2% of the reforested area been changed from grasslands, croplands, barren or sparsely vegetated land to closed shrublands and 20.6% from closed shrublands, grasslands, and croplands to forests. Reforestation changes land-surface properties, with possible impact on the evolution of atmospheric variables. To understand to what extent the local meteorology and environment could be affected by reforestation in winter, and through what processes, two sets of simulations were conducted using the Weather Research and Forecasting model (WRF) and the FLEXible PARTicle (FLEXPART) dispersion model for a control case with high-resolution remotely sensed land cover data for 2009 and a scenario assuming no reforestation since 1999. Results suggested that the changes in albedo, surface exchange coefficient and surface soil heat conductivity related to reforestation led to the changes in surface net radiation and surface energy partitioning, which in turn affected the meteorological fields and enhanced the mountain-valley wind circulation. Replacement of shrublands and grassland with forest in the south mountain through reforestation play a dominant role in the enhancement of mountain-valley wind circulation. Reforestation increased the amount of air exchanged between the valley and the outside during the day, with the largest hourly increase of 10% on calm weather days and a monthly mean hourly increase of 2% for the study period (Dec. 2009). Reforestation affected the spatial distribution of pollutants and slightly improved the urban air quality, especially in the eastern valley. Results from this study provide useful information for future urban air quality management and reforestation plan, and some experience for cities with similar situations in the

  2. Coastal Atmospheric-Oceanic Coupled System (CAOCS) for the South China Sea (SCS)-A Modeling Component of the International South China Sea Monsoon Experiment (SCSMEX)

    DTIC Science & Technology

    2016-06-07

    extending the current NOMP research project (the South China Sea prediction system) to a coastal air -ocean coupled prediction system and for...China Sea prediction system (POM) and to expand our modeling effort into a coastal air -ocean coupled model. APPROACH With the ONR support, I invited...Coastal Atmospheric-Oceanic Coupled System (CAOCS) for the South China Sea (SCS)-a Modeling Component of the International South China Sea Monsoon

  3. Three new species of woodlizards (Hoplocercinae, Enyalioides) from northwestern South America

    PubMed Central

    Torres-Carvajal, Omar; Venegas, Pablo J.; de Queiroz, Kevin

    2015-01-01

    Abstract The discovery of three new species of Enyalioides from the tropical Andes in Ecuador and northern Peru is reported. Enyalioides altotambo sp. n. occurs in northwestern Ecuador and differs from other species of Enyalioides in having dorsal scales that are both smooth and homogeneous in size, a brown iris, and in lacking enlarged, circular and keeled scales on the flanks. Enyalioides anisolepis sp. n. occurs on the Amazonian slopes of the Andes in southern Ecuador and northern Peru and can be distinguished from other species of Enyalioides by its scattered, projecting large scales on the dorsum, flanks, and hind limbs, as well as a well-developed vertebral crest, with the vertebrals on the neck at least three times higher than those between the hind limbs. Enyalioides sophiarothschildae sp. n. is from the Amazonian slopes of the Cordillera Central in northeastern Peru; it differs from other species of Enyalioides in having caudal scales that are relatively homogeneous in size on each caudal segment, a white gular region with a black medial patch and several turquoise scales in males, as well as immaculate white labials and chin. A molecular phylogenetic tree of 18 species of hoplocercines is presented, including the three species described in this paper and Enyalioides cofanorum, as well as an updated identification key for species of Hoplocercinae. PMID:25901116

  4. Three new species of woodlizards (Hoplocercinae, Enyalioides) from northwestern South America.

    PubMed

    Torres-Carvajal, Omar; Venegas, Pablo J; de Queiroz, Kevin

    2015-01-01

    The discovery of three new species of Enyalioides from the tropical Andes in Ecuador and northern Peru is reported. Enyalioidesaltotambo sp. n. occurs in northwestern Ecuador and differs from other species of Enyalioides in having dorsal scales that are both smooth and homogeneous in size, a brown iris, and in lacking enlarged, circular and keeled scales on the flanks. Enyalioidesanisolepis sp. n. occurs on the Amazonian slopes of the Andes in southern Ecuador and northern Peru and can be distinguished from other species of Enyalioides by its scattered, projecting large scales on the dorsum, flanks, and hind limbs, as well as a well-developed vertebral crest, with the vertebrals on the neck at least three times higher than those between the hind limbs. Enyalioidessophiarothschildae sp. n. is from the Amazonian slopes of the Cordillera Central in northeastern Peru; it differs from other species of Enyalioides in having caudal scales that are relatively homogeneous in size on each caudal segment, a white gular region with a black medial patch and several turquoise scales in males, as well as immaculate white labials and chin. A molecular phylogenetic tree of 18 species of hoplocercines is presented, including the three species described in this paper and Enyalioidescofanorum, as well as an updated identification key for species of Hoplocercinae.

  5. Implications of IODP Expedition 349 Age Results for the Spreading History of the South China Sea

    NASA Astrophysics Data System (ADS)

    Briais, Anne

    2016-04-01

    The International Ocean Discovery Program (IODP) Expedition 349 in the South China Sea drilled three sites (U1431, U1433, and U1434) into the basaltic crustal basement near the fossil spreading center in the East and Southwest Subbasins. These results provided age constraints on the termination of seafloor spreading in the South China Sea (SCS) basin. Shipboard biostratigraphic analysis of microfossils from the sediment immediately above or between flows in the basaltic basement indicates early Miocene ages: 16.7-17.6 Ma for Site U1431 in the East Subbasin, ~18-21 Ma for Site U1433 in the Southwest Subbasin. Since Expedition 349, Ar/Ar dating of basalt samples from these two sites have confirmed these ages in the east, and have provided an age of 17 Ma in the Southwest. The similarity in crustal age between sites suggests that the last stages of spreading have been coeaval in both the East and Southwest Subbasins, forming a single mid-ocean ridge system with a series of transform faults and discontinuities between the two subbasins. Expedition 349 also drilled Site U1435 on a bathymetric high along the northwestern continent-ocean boundary. Onboard core description, biostratigraphy and magnetostratigraphy revealed that sediment at this site shows a sharp discontinuity at about 33 Ma, interpreted to represent the breakup unconformity and date the beginning of seafloor spreading in the East Subbasin. The results of IODP Exp. 349, as well as results from deep-towed magnetic surveys, thus imply that oceanic seafloor spreading in the SCS, from 33 to ~16-18 Ma, is coeval with a large part of the left-lateral motion along the Ailao Shan-Red River Fault Zone (dated 34 to 17 Ma). This episode of the extension of the South China Sea basin is therefore more likely driven by the extrusion of the Indochina tectonic block resulting from the collision of India with Eurasia than by the subduction of a proto-South China Sea to the south.

  6. Paleoclimatic and paleomagnetic constraints on the Paleozoic reconstructions of south China, north China and Tarim

    NASA Astrophysics Data System (ADS)

    Shangyou, Nie

    1991-10-01

    Paleomagnetic and paleoclimatic data provide the most useful latitudinal constraints for plate reconstructions. Distributions through the Paleozoic of five types of climatically sensitive sediments (coals, evaporites, reefs, dolomites and limestones) for south China, north China and Tarim are shown on 15 maps that include 1578 reliable data points. These paleoclimatic data agree reasonably well with available paleomagnetic directions, although significant divergence between the two exists for the Early Paleozoic. These data indicate the following: (1) South China was in low latitudes during the entire Paleozoic, with a subtropical position in the Cambrian. (2) North China also remained near the equator in the Early and Late Paleozoic, except for the Ordovian and the Late Permian when extensive evaporites suggest slightly higher latitudinal positions, while its Middle Paleozoic position is uncertain due to the missing stratigraphie record. (3) In south China, local tectonics appears to have played a dominant role in determining paleogeography and therefore marine sedimentation, especially after the Late Ordovician-Early Silurian, because the areal coverage of marine sediments through time is distinctly different from what would be expected from published global sea-level curves. (4) Paleoclimatic and paleomagnetic data are compatible with biogeographic data which suggest that south China was part of eastern Gondwana in the Early Paleozoic, but was widely separated from Gondwana in the Late Paleozoic, and the split between the two probably happened in the Devonian, giving rise to a major break-up unconformity in central south China.

  7. Planaxidae (Mollusca, Gastropoda) from the South China Sea

    NASA Astrophysics Data System (ADS)

    Chen, Zhiyun; Zhang, Junlong; Lian, Xiping; Tan, Yehui

    2017-04-01

    Planaxidae is a family of tropical and subtropical marine gastropods that are adapted to an intertidal, rocky environment. The present study deals with three species in the family Planaxidae from the South China Sea: Planaxis sulcatus (von Born, 1778), Angiola longispira (Smith, 1872), and Supplanaxis niger (Quoy and Gaimard, 1833), based on specimens deposited in the Marine Biodiversity Collections of the South China Sea, Chinese Academy of Sciences. The taxonomic status, main morphological characteristics of the shell and radula, distribution, and habitat of these three planaxid species are presented. We also briefly discuss their morphological differences and the biogeographic distribution.

  8. Polybrominated diphenyl ethers in seafood products of south China.

    PubMed

    Guo, Jian-Yang; Wu, Feng-Chang; Mai, Bi-Xian; Luo, Xiao-Jun; Zeng, Eddy Y

    2007-10-31

    South China is probably one of the heaviest polybrominated diphenyl ether (PBDE) polluted regions in the world, thanks to the presence of huge and rapidly growing electronics manufacturing industries, as well as several of the world's largest e-waste recycling sites in the region. In the present work, a wide variety of nonfish seafood products collected from South China was analyzed for PBDE residues. The concentrations of PBDEs in seafood products were highly species-specific, and the magnitude of PBDE pollution was moderate in South China compared to the global levels. Congener patterns of PBDEs in seafood samples suggested that seafood products are prone to accumulating low-brominated congeners, and possible metabolic debromination of BDE-99 to BDE-47 could occur in certain organisms, such as crabs and mantis shrimp. Generally, the congener profile was dominated by BDE-209, and to a lesser extent by BDE-47 and BDE-99, which was consistent with the fact that Deca-BDE is mass-produced in China and with previous sediment results from the same area. The occurrence of BDE-209 in aquatic species from South China suggests that BDE-209 appears to be more bioavailable than previously thought, and the environmental fate and safety of BDE-209 require further investigation and call for a thorough reassessment.

  9. Sources and Delivery of Nutrients to the Northwestern Gulf of Mexico from Streams in the South-Central United States

    USGS Publications Warehouse

    Rebich, R.A.; Houston, N.A.; Mize, S.V.; Pearson, D.K.; Ging, P.B.; Evan, Hornig C.

    2011-01-01

    SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were developed to estimate nutrient inputs [total nitrogen (TN) and total phosphorus (TP)] to the northwestern part of the Gulf of Mexico from streams in the South-Central United States (U.S.). This area included drainages of the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf hydrologic regions. The models were standardized to reflect nutrient sources and stream conditions during 2002. Model predictions of nutrient loads (mass per time) and yields (mass per area per time) generally were greatest in streams in the eastern part of the region and along reaches near the Texas and Louisiana shoreline. The Mississippi River and Atchafalaya River watersheds, which drain nearly two-thirds of the conterminous U.S., delivered the largest nutrient loads to the Gulf of Mexico, as expected. However, the three largest delivered TN yields were from the Trinity River/Galveston Bay, Calcasieu River, and Aransas River watersheds, while the three largest delivered TP yields were from the Calcasieu River, Mermentau River, and Trinity River/Galveston Bay watersheds. Model output indicated that the three largest sources of nitrogen from the region were atmospheric deposition (42%), commercial fertilizer (20%), and livestock manure (unconfined, 17%). The three largest sources of phosphorus were commercial fertilizer (28%), urban runoff (23%), and livestock manure (confined and unconfined, 23%). ?? 2011 American Water Resources Association. This article is a U.S. Government work and is in the public domain in the USA.

  10. Crustal thickness estimates of Northwestern South America and their relation to the presence of batholithic bodies of economy interest

    NASA Astrophysics Data System (ADS)

    Hernandez, O.; von Frese, R. R.; Potts, L. M.

    2007-05-01

    A new model for the crustal evolution of northwestern South America (-8 S to 23.5 N, -90 W to -58.5 W) was developed from gravity derived MOHO depth estimates and tectonic features interpreted from correlative geopotential anomalies and seismic data. Crustal thickness estimates provide important constraints on the distribution of volcanic and seismic hazards, and mineral and energy deposits. Crustal thickness estimates were obtained by inversion of the compensated terrain gravity effects (CTGE) and compared against theoretical Airy MOHO and compiled seismic MOHO estimates. The thickness of the continental crust varies from 35 km to 55 km and shows that the mountain ranges are partially compensated by continental roots. The volumetric proportions of erupted rock types and geochemical characteristics likely are strongly correlated with the thickness and chemical characteristics of the crust through which the rising magmas travel. Crustal thicknesses from 45 to 55 km at the continent are related to the presence of andesitic batholiths of economic interest. Major deposits of base and precious metals of the Andean Mountains are related to intermediate to felsic intrusions. Porphyry copper-molybdenum deposits coincide with Mesozoic - Cenozoic orogenic belts and calc- alkaline volcanism. Major batholiths in the Central Andes, are related to gravity-inferred crustal thicknesses between 55 km to 60 km. Therefore, these results suggest that exploration of mineral deposits associated with batholithic intrusions in the Andes Mountains can be extended to crustal thicknesses from 45 km to 60 km.

  11. Permian storm current-produced offshore bars from an ancient shelf sequence : Northwestern Karoo basin, republic of South Africa

    NASA Astrophysics Data System (ADS)

    Smith, A. M.; Zawada, P. K.

    The Ecca-Beaufort transition zone from the Karoo Basin comprises upward-coarsening sequences which are interpreted as prograding, storm-produced offshore bars. Eight facies are recognised: (A) dark-grey shale, (B) thinly interbedded siltstone and mudstone, (C) thinly interbedded siltstone and very fine-grained sandstone, (D) blue-grey coarse-grained siltstone, (E) low-angle truncated and flat-laminated sandstone, (F) wave-rippled sandstone, (G) planar cross-bedded sandstone, (H) intraformational clay-pellet conglomerate. Four sub-environments are recognised, these being: (1) the bar crest which comprises proximal tempestites, (2) the bar slope consisting of soft-sediment deformed siltstone, (3) the bar fringe/ margin which is composed of storm layers and offshore siltstones and (4) the interbar/offshore environment comprising siltstone and distal storm layers. These bars formed in response to wave and storm processes and migrated across a muddy shelf environment. The orientation of bars was probably coast-parallel to subparallel with respect to the inferred north-northwest-south-southeast coastline. These proposed, storm-produced bars acted as major depo-centres within the shelf setting of the study area. As shelf sediments are recorded from almost the entire northwestern Karoo Basin it is anticipated that bar formation was an important sedimentary factor in the deposition of the sediments now referred to as the Ecca-Beaufort transition zone.

  12. Trends in streamflow and rainfall in tropical South America: Amazonia, eastern Brazil, and northwestern Peru

    NASA Astrophysics Data System (ADS)

    Marengo, José A.; Tomasella, Javier; Uvo, Cintia R.

    1998-01-01

    Long hydrological records, from the Amazon Basin, northeastern Brazil, and northwestern Peru spanning most of this century, are examined for trends in rainfall (three wettest months) and runoff (three months of highest flow) or stage, where no rating curves exist. Trends are tested for significance using the Mann-Kendall statistic. In basins where large soil, aquifer, or man-made reservoirs give rise to appreciable over-year storage, flows and water levels may be serially correlated. Where serial correlation exists, the usual statistical tests (linear regression, t-test, and Mann-Kendall) will overestimate the significance of trends, showing significance where none exists. Analysis for trend therefore requires particular care when data are serially correlated, and to avoid misleading results, additional supportive evidence must be sought. For example, rainfall records within the same river basin can be checked for trends; serial correlation in rainfall records, in particular, is less likely to be present, so the validity of any trends in rainfall is less open to question. Strong negative trends were found in flow data from the coast of northern Peru and the São Francisco River, while positive significant trends were detected in the Parnaíba River basin. No significant trends were found in the discharge or stage records from Amazonia, while rainfall in northeastern Brazil shows a slow increase over long periods. In the Parnaíba and in some rivers of northern Peru unusually large discharges at the beginning or end of the records seem to account for the direction and significance of trends.

  13. Properties of black carbon and other insoluble light-absorbing particles in seasonal snow of northwestern China

    NASA Astrophysics Data System (ADS)

    Pu, Wei; Wang, Xin; Wei, Hailun; Zhou, Yue; Shi, Jinsen; Hu, Zhiyuan; Jin, Hongchun; Chen, Quanliang

    2017-05-01

    A large field campaign was conducted and 284 snow samples were collected at 38 sites in Xinjiang Province and 6 sites in Qinghai Province across northwestern China from January to February 2012. A spectrophotometer combined with chemical analysis was used to measure the insoluble light-absorbing particles (ILAPs) and chemical components in seasonal snow. The results indicate that the cleanest snow was found in northeastern Xinjiang along the border of China, and it presented an estimated black carbon (CBCest) of approximately 5 ng g-1. The dirtiest snow presented a CBCest of approximately 450 ng g-1 near industrial cities in Xinjiang. Overall, the CBCest of most of the snow samples collected in this campaign was in the range of 10-150 ng g-1. Vertical variations in the snowpack ILAPs indicated a probable shift in emission sources with the progression of winter. An analysis of the fractional contributions to absorption implied that organic carbon (OC) dominated the 450 nm absorption in Qinghai, while the contributions from BC and OC were comparable in Xinjiang. Finally, a positive matrix factorization (PMF) model was run to explore the sources of particulate light absorption, and the results indicated an optimal three-factor/source solution that included industrial pollution, biomass burning, and soil dust.

  14. Greenhouse gas emissions from cotton field under different irrigation methods and fertilization regimes in arid northwestern China.

    PubMed

    Wu, Jie; Guo, Wei; Feng, Jinfei; Li, Lanhai; Yang, Haishui; Wang, Xiaohua; Bian, Xinmin

    2014-01-01

    Drip irrigation is broadly extended in order to save water in the arid cotton production region of China. Biochar is thought to be a useful soil amendment to reduce greenhouse gas (GHG) emissions. Here, a field study was conducted to compare the emissions of nitrous oxide (N2O) and methane (CH4) under different irrigation methods (drip irrigation (D) and furrow irrigation (F)) and fertilization regimes (conventional fertilization (C) and conventional fertilization + biochar (B)) during the cotton growth season. The accumulated N2O emissions were significantly lower with FB, DC, and DB than with FC by 28.8%, 36.1%, and 37.6%, while accumulated CH4 uptake was 264.5%, 226.7%, and 154.2% higher with DC, DB, and FC than that with FB, respectively. Irrigation methods showed a significant effect on total global warming potential (GWP) and yield-scaled GWP (P < 0.01). DC and DB showed higher cotton yield, water use efficiency (WUE), and lower yield-scaled GWP, as compared with FC and FB. This suggests that in northwestern China mulched-drip irrigation should be a better approach to increase cotton yield with depressed GHG. In addition, biochar addition increased CH4 emissions while it decreased N2O emissions.

  15. Greenhouse Gas Emissions from Cotton Field under Different Irrigation Methods and Fertilization Regimes in Arid Northwestern China

    PubMed Central

    Guo, Wei; Feng, Jinfei; Li, Lanhai; Yang, Haishui; Wang, Xiaohua; Bian, Xinmin

    2014-01-01

    Drip irrigation is broadly extended in order to save water in the arid cotton production region of China. Biochar is thought to be a useful soil amendment to reduce greenhouse gas (GHG) emissions. Here, a field study was conducted to compare the emissions of nitrous oxide (N2O) and methane (CH4) under different irrigation methods (drip irrigation (D) and furrow irrigation (F)) and fertilization regimes (conventional fertilization (C) and conventional fertilization + biochar (B)) during the cotton growth season. The accumulated N2O emissions were significantly lower with FB, DC, and DB than with FC by 28.8%, 36.1%, and 37.6%, while accumulated CH4 uptake was 264.5%, 226.7%, and 154.2% higher with DC, DB, and FC than that with FB, respectively. Irrigation methods showed a significant effect on total global warming potential (GWP) and yield-scaled GWP (P < 0.01). DC and DB showed higher cotton yield, water use efficiency (WUE), and lower yield-scaled GWP, as compared with FC and FB. This suggests that in northwestern China mulched-drip irrigation should be a better approach to increase cotton yield with depressed GHG. In addition, biochar addition increased CH4 emissions while it decreased N2O emissions. PMID:25133229

  16. Characterizations of volatile organic compounds (VOCs) from vehicular emissions at roadside environment: The first comprehensive study in Northwestern China

    NASA Astrophysics Data System (ADS)

    Li, Bowei; Ho, Steven Sai Hang; Xue, Yonggang; Huang, Yu; Wang, Liqin; Cheng, Yan; Dai, Wenting; Zhong, Haobin; Cao, Junji; Lee, Shuncheng

    2017-07-01

    Vehicular emission (VE) is one of the important anthropogenic sources for ground-level volatile organic compounds (VOCs) in both urban and suburban areas. A first comprehensive campaign was conducted at an urban roadside in Xi'an, China in summer, 2016. A total of 57 VOCs, as known as critical surface ozone (O3) precursors, and other trace gases were measured simultaneously during the sampling period. Iso-pentane, a tracer of gasoline evaporation, was the most abundant VOC in the roadside samples, followed by isobutane and benzene, attributed to the largest composition (∼70%) of gasoline-fueled vehicles on the road. The molar ratio of toluene/benzene (T/B) in our study (0.36) is far lower than the range reported in other cities, indicating the stronger contributions from diesel emissions. The results of source apportionment achieved with positive matrix factorization (PMF) receptor model were highly consistent with the vehicles compositions, strongly evidenced that the precise characterization of the VE sources from those marker species. The degrees of individual compound contributed to O3 production were weighed by ozone formation potential (OFP). Propylene (20%), 1-butene (11%) and iso-pentane(10%) were the top three contributors at the roadside. The information of this study complements the VOCs database regarding to the VE sources in Northwestern China.

  17. Mixed volcanogenic-lithogenic sources for Permian bauxite deposits in southwestern Youjiang Basin, South China, and their metallogenic significance

    NASA Astrophysics Data System (ADS)

    Yu, Wenchao; Algeo, Thomas J.; Du, Yuansheng; Zhang, Qilian; Liang, Yuping

    2016-07-01

    Bauxite deposits at the base of the Upper Permian Heshan Formation in the Youjiang Basin, South China, contain zircons with dominant age peaks at 263-262 Ma. During the Middle to Late Permian, the Youjiang Basin consisted of a number of isolated and attached carbonate platforms separated by inter-platform troughs. The bauxite deposits are limited to the isolated carbonate platform facies and are not present on attached carbonate platforms and inter-platform troughs. Discriminant plots based on the trace element composition of the zircons indicate a combination of within-plate/anorogenic and arc-related/orogenic sources. Geochemical and isotopic data suggest that the metallogenic materials of the bauxite deposit came from felsic volcanic rocks of the Emeishan Large Igneous Provence (ELIP) in South China and from the Truong Son volcanic arc located between the South China and Indochina cratons. The northwestern and southeastern parts of the Youjiang Basin received larger amounts of ELIP detritus and volcanic arc detritus, respectively. Coarser siliciclastic material in proximal attached carbonate platform and inter-platform trough settings was delivered by rivers, but finer siliciclastics that accumulated on distally located carbonate platforms in isolated deep-water areas was probably transported by wind.

  18. [Chemical characteristics of precipitation in South China Sea].

    PubMed

    Xiao, Hong-Wei; Long, Ai-Min; Xie, Lu-Hua; Xiao, Hua-Yun; Liu, Cong-Qiang

    2014-02-01

    Rainwater samples were collected in the summer on "Shiyan 3" during the 2012 South China Sea Sectional Scientific Survey. The concentrations of anion and cation, and pH in precipitation were determined and backward trajectories of air mass were simulated to analyze the chemical characteristics of ions and examine the source of ions. The results indicated that the mean pH value of precipitation was 6.3, with 5.6 of minimal value in summer in South China Sea. The order of anion and cation abundance was Cl(-) > S04(2-) > NO3(-) and Na(+) > Mg(2+) > Ca(2+) > K(+). Cl(-) was the major anion and Na(+) was the major cation, with concentrations of 2 637.5 microeq x L(-1) and 2095.5 microeq x L(-1), respectively, showing that they were the characteristics of marine atmospheric precipitation. There was a good linear relationship between each pair of 7 ions, with correlation coefficient above 0.9, suggesting that they may have a common source. However, the correlation coefficients were lower between NO3(-) and other ions than the others, suggesting that NO3(-) had more complex sources. The concentrations of Ca(2+) and K(+) in precipitation may be related to coral environment in South China Sea. The backward trajectories in 6 stations showed that the air mass was from south and southwest of South China Sea, without passing through above the continent. These results suggested that precipitation affected by human ion source can be ignored in summer in South China Sea.

  19. Trophic flows, ecosystem structure and fishing impacts in the South Catalan Sea, Northwestern Mediterranean

    NASA Astrophysics Data System (ADS)

    Coll, Marta; Palomera, Isabel; Tudela, Sergi; Sardà, Francesc

    2006-01-01

    An exploited ecosystem from the continental shelf and upper slope of the Northwestern Mediterranean Sea was described by means of an Ecopath mass-balance model with the aim of characterising its functioning and structure and describing the ecosystem impacts of fishing. This application included some complexities added to the general modelling methodology due to the high biodiversity of the Mediterranean Sea and the multispecific nature of the fishery, and to the difficulties of working with fishing data which are usually irregularly or imprecisely collected. The model comprised 40 functional groups including primary producers, the main species of benthic, demersal and pelagic invertebrates, fishes and non-fish vertebrates and three detritus groups. In addition, trawling, purse seine, longline and troll bait fishing fleets were included. Results showed that the functional groups were organized into four trophic levels with the highest levels corresponding to anglerfish, dolphins, large pelagic fishes and adult hake. The system was dominated by the pelagic fraction, where sardine and anchovy prevailed in terms of fish biomasses and catches. Detritus and detritivorous groups also played key roles in the ecosystem and important coupled pelagic-demersal interactions were described. Considering Odum's theory of ecosystem development, the ecosystem was placed on an intermediate-low developmental stage due, at least partially, to the impact of fishing activity. This highlighted the high intensity of fishing in the ecosystem, in accordance with the general assessment of western Mediterranean marine resources, and fishing fleets were ranked as top predators of the system. The low trophic level of the catch was in line with the long history of exploitation in the area. However, the steady decline of pelagic landings between 1994 and 2003, coupled with a decrease of the pelagic biomass within the system, underlined the low resistance of the system in front of perturbations

  20. Intensified pluvial conditions during the twentieth century in the inland Heihe River Basin in arid northwestern China over the past millennium

    NASA Astrophysics Data System (ADS)

    Qin, Chun; Yang, Bao; Burchardt, Iris; Hu, Xiaoli; Kang, Xingcheng

    2010-06-01

    Past streamflow variability is of special significance in the inland river basin, i.e., the Heihe River Basin in arid northwestern China, where water shortage is a serious environmental and social problem. However, the current knowledge of issues related to regional water resources management and long-term planning and management is limited by the lack of long-term hydro-meteorological records. Here we present a 1009-year annual streamflow (August-July) reconstruction for the upstream of the Heihe River in the arid northwestern China based on a well-replicated Qilian juniper ( Sabina przewalskii Kom.) ring-width chronology. This reconstruction accounts for 46.9% of the observed instrumental streamflow variance during the period 1958-2006. Considerable multidecadal to centennial flow variations below and above the long-term average are displayed in the millennium streamflow reconstruction. These periods 1012-1053, 1104-1212, 1259-1352, 1442-1499, 1593-1739 and 1789-1884 are noteworthy for the persistence of low-level river flow, and for the fact that these low streamflow events are not found in the observed instrumental hydrological record during the recent 50 years. The 20th century witnessed intensified pluvial conditions in the upstream of the Heihe River in the arid northwestern China in the context of the last millennium. Comparison with other long-term hydrological reconstructions indicates that the intensification of the hydrological cycle in the twentieth century from different regions could be attributable to regional to large-scale temperature increase during this time. Furthermore, from a practical perspective, the streamflow reconstruction can serve as a robust database for the government to work out more scientific and more reasonable water allocation alternatives for the Heihe River Basin in arid northwestern China.

  1. The complexity of South China Sea kinematics

    NASA Astrophysics Data System (ADS)

    Sibuet, Jean-Claude; Gao, Jinyao; Zhao, Minghui; Wu, Jonny; Ding, Weiwei; Yeh, Yi-Ching; Lee, Chao-Shing

    2016-04-01

    Magnetic modeling shows that the age of the youngest South China Sea (SCS) oceanic crust is controversial (e.g. 15.5 Ma, Briais et al., JGR 1993 and 20.5 Ma, Barckhausen et al., MPG 2014). Close to the rift axis of the East sub-basin, Ar-Ar age dating of oceanic crustal rocks collected during IODP Leg 349 gives ages of 15 and 15.2 +/- 0.2 Ma (Koppers, Fall AGU meeting, 2014), which seems to favor the 15.5 Ma age given by Briais et al. modeling. However, basaltic samples might belong to a sill and not to the typical oceanic crust. As post-spreading magmatic activity (~8-13 Ma) largely masks the spreading fabric, in particular near the previously identified E-W portion of the extinct ridge axis of the East sub-basin, the published locations of the axial magnetic anomaly and spreading rates are incorrect. The compilation of available swath bathymetric data shows that if post-spreading volcanics hide the seafloor spreading magnetic fabric mostly along and near the extinct spreading axis, the whole SCS is globally characterized by rift directions following three directions: N055°in the youngest portion of the SCS, N065° and N085° in the oldest portions of the SCS (Sibuet et al., Tectonophysics 2016) suggesting the extinct ridge axis is N055° trending instead of E-W. We present an updated version of the whole SCS structural sketch based on previously published swath bathymetric trends and new detailed magnetic lineations trends compiled from an extremely dense set of magnetic data. The new structural sketch shows: - The distribution of conjugate kinematic domains, - The early opening of the NW and East sub-basins, before a jump of the rift axis, - A second ridge jump in the East basin, - The different expressions of the post-spreading magmatism in the East and SW sub-basins. In the East sub-basin, crustal magmatic intrusions led to the formation of extrusive basalts associated with the presence of numerous volcanoes (Wang et al., Geological Journal 2016). In the SW

  2. Antecedents of Medical Workplace Violence in South China

    ERIC Educational Resources Information Center

    Cai, Wenzhi; Deng, Ling; Liu, Meng; Yu, Min

    2011-01-01

    It has been noted that workplace violence most frequently occurs in hospitals. The purpose of this study was to explore antecedents of workplace violence in south China. The authors conducted face-to-face, in-depth, semistructured interviews with 30 hospital staff who had experienced at least one incident of workplace violence from patients during…

  3. Antecedents of Medical Workplace Violence in South China

    ERIC Educational Resources Information Center

    Cai, Wenzhi; Deng, Ling; Liu, Meng; Yu, Min

    2011-01-01

    It has been noted that workplace violence most frequently occurs in hospitals. The purpose of this study was to explore antecedents of workplace violence in south China. The authors conducted face-to-face, in-depth, semistructured interviews with 30 hospital staff who had experienced at least one incident of workplace violence from patients during…

  4. Characterizing Surface Transport Barriers in the South China Sea

    DTIC Science & Technology

    2013-09-30

    location of submesoscale fronts in the South China Sea (SCS). OBJECTIVES The scientific objective is to test and develop novel methods, with a focus...transport prooperties of unsteady flows. Applications range from improved fundamental understanding of the relationship between submesoscale fronts

  5. Accommodation of compressional inversion in north-western South Island (New Zealand): Old faults versus new?

    NASA Astrophysics Data System (ADS)

    Ghisetti, F. C.; Sibson, R. H.

    2006-11-01

    In the NW South Island, New Zealand, high-angle faults inherited from episodes of Late Cretaceous-Paleocene and Eocene extension have, since the early Miocene, undergone compressional inversion in association with right-lateral shearing and transpression on the Alpine Fault. Active reverse faulting and large historical earthquakes occur along N-S to NNE-SSW trending faults which at the surface dip 45-75° to both the east and west. The faults truncate subparallel folds that deform the Tertiary sequence overlying a composite Paleozoic-Mesozoic crystalline basement. However, the deep geometry of these faults, their penetration into the middle-to-lower crust and their relationship to the Alpine Fault are poorly understood. The tectonic architecture of this compressional inversion province is analysed by reconstructing structural contours at the base of the Oligocene carbonate sequence in the north-west of the South Island. Deformation of the Oligocene carbonate sequence, structural analyses in the field and subsurface data indicate a mixed style of inversion with (1) reactivation of some high-angle normal faults and (2) thrusting on new, moderate-dipping cross-cutting faults that detach slivers of basement and cause flexural folding in the sedimentary cover. These faults may remain blind or concealed beneath cover sequences but are likely to control seismic rupturing in the basement at depths of ˜10-15 km.

  6. Ovi-caprid dung as an indicator of paleovegetation and paleoclimate in northwestern China

    NASA Astrophysics Data System (ADS)

    Ghosh, Ruby; Gupta, Sudha; Bera, Subir; Jiang, Hong-en; Li, Xiao; Li, Cheng-Sen

    2008-09-01

    Diverse palynomorphs and phytoliths recovered from coprolites of ovi-caprids (sheep, goat) collected from Yang-Hai Tomb at Xinjiang Province, China, have been used to elucidate the dietary pattern of ancient livestock and to reconstruct the paleovegetation and paleoclimate of this part of northwest China ca. 2500 14C yr BP. Palynological and phytolith data suggest that a rich dry temperate vegetation prevailed in the area during the said period. Climatic conditions and grassland vegetation type of the area are explored using phytolith indices.

  7. The Role of Soft Power in China’s Security Strategy: Case Studies on the South China Sea and Taiwan

    DTIC Science & Technology

    2017-06-09

    THE ROLE OF SOFT POWER IN CHINA’S SECURITY STRATEGY : CASE STUDIES ON THE SOUTH CHINA SEA AND TAIWAN A thesis presented to the...in the South China Sea. The study demonstrates that soft power is integrated into China’s security strategy , and involves a wide range of sources...Thesis Title: The Role of Soft Power in China’s Security Strategy : Case Studies on the South China Sea and Taiwan Approved by

  8. The Vichada Impact Crater in Northwestern South America and its Potential for Economic Deposits

    NASA Astrophysics Data System (ADS)

    Hernandez, O.; von Frese, R. R.

    2008-05-01

    A prominent positive free-air gravity anomaly mapped over a roughly 50-km diameter basin is consistent with a mascon centered on (4o30`N, -69o15`W) in the Vichada Department, Colombia, South America. The inferred large impact crater is nearly one third the size of the Chicxulub crater. It must have formed recently, in the last 30 m.a. because it controls the partially eroded and jungle-covered path of the Vichada River. No antipodal relationship has been detected. Thick sedimentary cover, erosional processes and dense vegetation greatly limit direct geological testing of the inferred impact basin. However, EGM-96 gravity data together with ground gravity and magnetic profiles support the interpretation of the impact crater structure. The impact extensively thinned and disrupted the Precambrian cratonic crust and may be associated with mineral and hydrocarbon deposits. A combined EM and magnetic airborne program is being developed to resolve additional crustal properties of the inferred Vichada impact basin Keywords: Impact crater, economic deposits, free-air gravity anomalies

  9. Evolutionary History of a Desert Shrub Ephedra przewalskii (Ephedraceae): Allopatric Divergence and Range Shifts in Northwestern China

    PubMed Central

    Su, Zhi-Hao; Zhang, Ming-Li

    2016-01-01

    Based on two chloroplast DNA sequences, psbA-trnH and trnT-trnF, phylogeographical patterns of a desert shrub, Ephedra przewalskii, were examined across most of its geographic range in northwestern China. A total of sixteen haplotypes were detected. There was a common haplotype in each basin, that was haplotype A in Tarim Basin, haplotype G in Junggar Basin, and haplotype M in Qaidam Basin. Genetic variance mainly occurred among populations, geographic regions, and eleven geographic groups subdivided by SAMOVA analysis. E. przewalskii likely had a smaller and more fragmented geographic range during the Last Glacial Maximum, which was determined based on ecological niche modelling. Three groups of E. przewalskii populations were detected to have experience range expansion, and this was based on significant values of Fu’s FS, Tajima’s D, and unimodel mismatch distributions. The cold and dry climate during the glacial period of the Quaternary is postulated to have been a driver for significant genetic isolation and divergence among populations or groups in E. przewalskii, whereas the warmer and wetter climate during the interglacial period is speculated to have provided favourable conditions for range expansion of the species. PMID:27351630

  10. Geochemical characterization of Lucaogou Formation and its correlation of tight oil accumulation in Jimsar Sag of Junggar Basin, Northwestern China.

    PubMed

    Qu, Jiangxiu; Ding, Xiujian; Zha, Ming; Chen, Hong; Gao, Changhai; Wang, Zimeng

    2017-01-01

    With the constant consumption of conventional oil and gas resources, unconventional oil and gas resources with great resource potential such as tight oil have gradually been valued and become the new exploration area. Jimsar Sag is the key tight oil exploration and development block in Junggar Basin of Northwestern China. Based on the data sets of geology, oil production test, logging, rock thin section, and geochemistry of Permian Lucaogou Formation (LCG), we studied the geochemical characteristics of hydrocarbon source rocks and their relation to the tight oil accumulation. Organic matter abundance of source rocks is high, the types of organic matter are mainly type I and type II, and the organic matter maturation is in the low mature stage to mature stage. Results of oil source correlation showed that the crude oil of sweet spots was mainly derived from the source rocks in the interior of the sweet spots. The LCG tight oil is mainly distributed in the plane where the source rocks have great thickness and the TOC is higher than 3.5%. It shows that the source rocks have obvious controlling on the occurrence and accumulation of tight oil.

  11. Impacts of river recharge on groundwater level and hydrochemistry in the lower reaches of Heihe River Watershed, northwestern China

    NASA Astrophysics Data System (ADS)

    Xi, Haiyang; Feng, Qi; Si, Jianhua; Chang, Zongqiang; Cao, Shengkui

    2010-05-01

    Water resources have been overexploited for agricultural irrigation and industrial production in the upper and middle reaches of the Heihe River, northwestern China. Due to inadequate water resources management, the runoff entering into the lower reaches has been continuously reduced in recent years. The Heihe River is the primary recharge source for the groundwater of the lower reaches, so the decrease in runoff has caused the groundwater level to decline. As a result, a series of ecological and environmental problems has now appeared in the lower reaches, including river-flow interruptions, drying up of associated lakes, degeneration of vegetative cover and so on. In view of these issues, the National Water Diversion Project was put into practice in July 2000. It has significantly increased the quantity and frequency of flows entering into the lower reaches of the Heihe River, and has recharged the groundwater and improved the water quality to some degree along the length of the river. The water deliveries have had obvious influences on the groundwater in the lower reaches. The groundwater level increase and groundwater quality improvement have been of great benefit in restoring the ecological environment that was destroyed in past years.

  12. Changes in mean and extreme temperature and precipitation over the arid region of northwestern China: Observation and projection

    NASA Astrophysics Data System (ADS)

    Wang, Yujie; Zhou, Botao; Qin, Dahe; Wu, Jia; Gao, Rong; Song, Lianchun

    2017-03-01

    This paper reports a comprehensive study on the observed and projected spatiotemporal changes in mean and extreme climate over the arid region of northwestern China, based on gridded observation data and CMIP5 simulations under the RCP4.5 and RCP8.5 scenarios. The observational results reveal an increase in annual mean temperature since 1961, largely attributable to the increase in minimum temperature. The annual mean precipitation also exhibits a significant increasing tendency. The precipitation amount in the most recent decade was greater than in any preceding decade since 1961. Seasonally, the greatest increase in temperature and precipitation appears in winter and in summer, respectively. Widespread significant changes in temperature-related extremes are consistent with warming, with decreases in cold extremes and increases in warm extremes. The warming of the coldest night is greater than that of the warmest day, and changes in cold and warm nights are more evident than for cold and warm days. Extreme precipitation and wet days exhibit an increasing trend, and the maximum number of consecutive dry days shows a tendency toward shorter duration. Multi-model ensemble mean projections indicate an overall continual increase in temperature and precipitation during the 21st century. Decreases in cold extremes, increases in warm extremes, intensification of extreme precipitation, increases in wet days, and decreases in consecutive dry days, are expected under both emissions scenarios, with larger changes corresponding to stronger radiative forcing.

  13. Energy and CO2 exchanges and influencing factors in spring wheat ecosystem along the Heihe River, northwestern China

    NASA Astrophysics Data System (ADS)

    Sun, Shuchen; Shao, Ming'an; Gao, Hongbei

    2016-12-01

    Spring wheat ( Triticum aestivum Linn.) is an important crop for food security in the desert-oasis farmland in the middle reaches of the Heihe River in northwestern China. We measured fluxes using eddy covariance and meteorological parameters to explore the energy fluxes and the relationship between CO2 flux and climate change in this region during the wheat growing seasons in 2013 and 2014. The energy balance closures were 70.5% and 72.7% in the 2013 and 2014 growing season, respectively. The wheat ecosystem had distinct seasonal and diurnal dynamics of CO2 fluxes with U-shaped curves. The accumulated net ecosystemic CO2 exchanges (NEE) were -111.6 and -142.2 g C/m2 in 2013 and 2014 growing season, respectively. The ecosystem generally acted as a CO2 sink during the growing season but became a CO2 source after the wheat harvest. A correlation analysis indicated that night-time CO2 fluxes were exponentially dependent on air temperature and soil temperature at a depth of 5 cm but were not correlated with soil-water content, water-vapour pressure, or vapour-pressure deficit. CO2 flux was not correlated with the meteorological parameters during daytime. However, irrigation and precipitation, may complicate the response of CO2 fluxes to other meteorological parameters.

  14. Agricultural water supply/demand changes under projected future climate change in the arid region of northwestern China

    NASA Astrophysics Data System (ADS)

    Guo, Ying; Shen, Yanjun

    2016-09-01

    The water resources in the arid region of northwestern China, which are impacted by climate change, tend to be more unstable, and the environment and ecosystems will suffer from severe water shortage. In this paper, potential future climate trends were predicted based on CMIP5 simulations in this region. The water availability and agricultural water demand under future climate change scenarios were estimated. Impacted by increases in temperature, the irrigation water demand will increase by 4.27-6.15 billion m3 in this region over the next 60 years, compared to the demand of 32.75 billion m3 during 1971-2000. However, the annual runoff will only increase by 4.8-8.5 billion m3, which is equivalent to or even less than the increased irrigation water demand. In fact, the increased demand for industrial, domestic and ecological water were not considered here. Thus, the water supply/demand contradiction will result in more severe water shortages in the future. According to a comparison with simulated irrigation water demand under three adaptation strategy scenarios, we should take effective measures such as improving the efficiency of irrigation water utilization, reducing crop planting areas and adjusting crop planting structures to alleviate the impacts of future climate changes and human activities on the water supply and water use in this region.

  15. Modeling nitrate leaching and optimizing water and nitrogen management under irrigated maize in desert oases in Northwestern China.

    PubMed

    Hu, Kelin; Li, Yong; Chen, Weiping; Chen, Deli; Wei, Yongping; Edis, Robert; Li, Baoguo; Huang, Yuanfang; Zhang, Yuanpei

    2010-01-01

    Understanding water and N transport through the soil profile is important for efficient irrigation and nutrient management to minimize nitrate leaching to the groundwater, and to promote agricultural sustainable development in desert oases. In this study, a process-based water and nitrogen management model (WNMM) was used to simulate soil water movement, nitrate transport, and crop growth (maize [Zea mays L.]) under desert oasis conditions in northwestern China. The model was calibrated and validated with a field experiment. The model simulation results showed that about 35% of total water input and 58% of the total N input were leached to <1.8 m depth under traditional management practice. Excessive irrigation and N fertilizer application, high nitrate concentration in the irrigation water, together with the sandy soil texture, resulted in large nitrate leaching. Nitrate leaching was significantly reduced under the improved management practice suggested by farm extension personnel; however, the water and nitrate inputs still far exceeded the crop requirements. More than 1700 scenarios combining various types of irrigation and fertilizer practices were simulated. Quantitative analysis was conducted to obtain the best management practices (BMPs) with simultaneous consideration of crop yield, water use efficiency, fertilizer N use efficiency, and nitrate leaching. The results indicated that the BMPs under the specific desert oasis conditions are to irrigate the maize with 600 mm of water in eight times with a single fertilizer application at a rate of 75 kg N ha(-1).

  16. Dietary shift after 3600 cal yr BP and its influencing factors in northwestern China: Evidence from stable isotopes

    NASA Astrophysics Data System (ADS)

    Ma, Minmin; Dong, Guanghui; Jia, Xin; Wang, Hui; Cui, Yifu; Chen, Fahu

    2017-04-01

    :Human diets rely on natural resource availability and can reflect social and cultural values. When environments, societies, and cultures change, diets may also shift. This study traced the extent of dietary change and the factors influencing such change. Through stable carbon and nitrogen isotopic analysis of late Neolithic and early Bronze Age human and animal bone collagen, we found that significant shifts in human diets were closely associated with intercontinental cultural exchanges in Eurasia and climate change in northwestern China. The isotopic evidence indicated that human diets mainly consisted of C4 foodstuffs (presumably millet and/or animals fed with C4 foods) around 4000 calibrated years before the present (cal yr BP), corresponding to the flourishing of millet agriculture in the context of the optimal climate conditions of the mid-Holocene. Subsequently, more C3 foods (probably wheat, barley, and animals fed with C3 foods) were added to human diets post-3600 cal yr BP when the climate became cooler and drier. Such dietary variation is also consistent with the increasing intensity of long-distance exchange after 4000 cal yr BP. While many factors can lead to human dietary shifts (e.g. climate change, population growth, cultural factors, and human migration), climate may have been a key factor in Gansu and Qinghai.

  17. Dietary shift after 3600 cal yr BP and its influencing factors in northwestern China: Evidence from stable isotopes

    NASA Astrophysics Data System (ADS)

    Ma, Minmin; Dong, Guanghui; Jia, Xin; Wang, Hui; Cui, Yifu; Chen, Fahu

    2016-08-01

    Human diets rely on natural resource availability and can reflect social and cultural values. When environments, societies, and cultures change, diets may also shift. This study traced the extent of dietary change and the factors influencing such change. Through stable carbon and nitrogen isotopic analysis of late Neolithic and early Bronze Age human and animal bone collagen, we found that significant shifts in human diets were closely associated with intercontinental cultural exchanges in Eurasia and climate change in northwestern China. The isotopic evidence indicated that human diets mainly consisted of C4 foodstuffs (presumably millet and/or animals fed with C4 foods) around 4000 calibrated years before the present (cal yr BP), corresponding to the flourishing of millet agriculture in the context of the optimal climate conditions of the mid-Holocene. Subsequently, more C3 foods (probably wheat, barley, and animals fed with C3 foods) were added to human diets post-3600 cal yr BP when the climate became cooler and drier. Such dietary variation is also consistent with the increasing intensity of long-distance exchange after 4000 cal yr BP. While many factors can lead to human dietary shifts (e.g. climate change, population growth, cultural factors, and human migration), climate may have been a key factor in Gansu and Qinghai.

  18. A hundred year record of anthropogenic influences on the sedimentary geochemistry from Lake Sayram, Tianshan Mountains in northwestern China

    NASA Astrophysics Data System (ADS)

    Wu, J.; Shen, B.

    2016-12-01

    Northwestern China has many arid inland lakes and wetlands, and it is characterized with climate variability and human impact. Lake Sayram is a deep, closed lake in the Tianshan Mountains of northwest China. In this study, we explore the trajectory of recent climate and environmental change using a 30-cm sediment record obtained from the center of Lake Sayram. With 210Pb and 137Cs dating and organic-inorganic geochemical methods, including element content, carbonate content, δ13C andδ18O of bulk carbonate, source-specific biomarkers and polycyclic aromatic hydrocarbons (PAHs), we reconstruct regional environmental change over the past about 100 yrs. High evaporation modifies δ13C andδ18O of the dissolved inorganic carbon in lake water and may be responsible for the covariance between δ13C andδ18O of bulk carbonate. Alkenone unsaturation indices are associated with climatic change, and the PAHs and metal contents reflect the impacts of human activities. Constrained cluster analysis of the multi-proxy indices was used to partition sediment deposition into three periods. Prior to 1960, the climate was dryer with high evaporation, and lake water had higher salinity. The vertical distributions of PAHs had little changed and low molecular weight PAHs were dominated PAHs. In this period, there existed one obvious drier climatic event at about 1920s with the sediment record of aeolian dust transport. From the 1960s to 1990s, high molecular weight PAHs and heavy metal delivery to sediments increased slowly, associated with relatively weak economic development in Xinjiang region. Thereafter, contamination by heavy metals increased markedly, especially after the 1990s, a sharp increase in PAHs level and individuals was observed too. The results clearly demonstrate that the environmental change in Lake Sayram before the 1960s strongly depended on the natural discharge, whereas at later stages, it was significantly influenced by human activities.

  19. Contrasting Triassic ferroan granitoids from northwestern Liaoning, North China: Magmatic monitor of Mesozoic decratonization and a craton-orogen boundary

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaohui; Yuan, Lingling; Xue, Fuhong; Zhang, Yanbin

    2012-07-01

    The diversity exhibited by ferroan granitoids testifies to multiple distinct crustal and mantle processes generally within extensional environments and thus holds the key to monitoring important geodynamic and crustal evolutionary processes and calibrating terrane tectonic affinity. This study documents three Middle to Late Triassic ferroan granitoid suites from northwestern Liaoning, North China, and proposes distinct petrogenetic scenarios for each. The Middle Triassic (ca. 238 Ma) Ping'andi (PAD) granites are mainly calc-alkali and peraluminous. Their radiogenic whole-rock Nd and zircon Hf isotopic signatures argue for an origin consistent with partial melting of a juvenile quartzofeldspathic crust formed by prior mantle-derived magmatic underplating and their differentiations. By contrast, the Late Triassic (ca. 220 Ma) Dashaoleng (DSL) and Sijiazi (SJZ) suites show an evolved character from alkali-calcic to alkali and from metaluminous to peraluminous. Their variably evolved whole-rock Sr-Nd and mixed zircon Hf isotopic compositions suggest that both suites were formed by variable mixing between depleted mantle-derived mafic magma and old crust-derived felsic magma, with distinctively higher input from juvenile components in the DSL suite. These contrasting ferroan granitoid suites not only provide a spatial marker for monitoring juxtaposition of the North China Craton (NCC) and the Central Asian Orogenic Belt (CAOB) along a lithospheric-scale boundary fault in the region, but also present a temporal snapshot that records a southwardly-progressing crustal growth scenario possibly in response to lithospheric dripping within a post-orogenic extensional regime. The cratonic scale synthesis further indicates that diachronous decratonization pattern of the NCC might record episodic response of the craton to evolved plate tectonic processes with two contrasting Phanerozoic orogenic systems.

  20. Decadal variability of chlorophyll a in the South China Sea: a possible mechanism

    NASA Astrophysics Data System (ADS)

    Liu, Fenfen; Chen, Chuqun; Zhan, Haigang

    2012-11-01

    Four climatologies on a monthly scale (January, April, May and November) of chlorophyll a within the South China Sea (SCS) were calculated using a Coastal Zone Color Scanner (CZCS) (1979-1983) and the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) (1998-2002). We analyzed decadal variability of chlorophyll a by comparing the products of the two observation periods. The relationships of variability in chlorophyll a with sea surface wind speed (SSW), sea surface temperature (SST), wind stress (WS), and mixed layer depth (MLD) were determined. The results indicate that there is obvious chlorophyll a decadal variability in the SCS. The decadal chlorophyll a presents distinct seasonal variability in characteristics, which may be as a result of various different dynamic processes. The negative chlorophyll a concentration anomaly in January was associated with the warming of SST and a shallower MLD. Generally, there were higher chlorophyll a concentrations in spring during the SeaWiFS period compared with the CZCS period. However, the chlorophyll a concentration exhibits some regional differences during this season, leading to an explanation being diffi cult. The deepened MLD may have contributed to the positive chlorophyll a concentration anomalies from the northwestern Luzon Island to the northeastern region of Vietnam during April and May. The increases of chlorophyll a concentration in northwestern Borneo during May may be because the stronger SSW and higher WS produce a deeper mixed layer and convective mixing, leading to high levels of nutrient concentrations. The higher chlorophyll a off southeastern Vietnam may be associated with the advective transport of the colder water extending from the Karimata Strait to southeastern Vietnam.

  1. Crustal structure and inferred extension mode in the northern margin of the South China Sea

    NASA Astrophysics Data System (ADS)

    Gao, J.; Wu, S.; McIntosh, K. D.; Mi, L.; Spence, G.

    2016-12-01

    Combining multi-channel seismic reflection and satellite gravity data, this study has investigated the crustal structure and magmatic activities of the northern South China Sea (SCS) margin. Results show that a broad continent-ocean transition zone (COT) with more than 140 km wide is characterized by extensive igneous intrusion/extrusion and hyper-extended continental crust in the northeastern SCS margin, a broader COT with 220-265 km wide is characterized by crustal thinning, rift depression, structural highs with igneous rock and perhaps a volcanic zone or a zone of tilted fault blocks at the distal edge in the mid-northern SCS margin, and a narrow COT with 65 km wide bounded seawards by a volcanic buried seamount is characterized by extremely hyper-extended continental crust in the northwestern SCS margin, where the remnant crust with less than 3 km thick is bounded by basin-bounding faults corresponding to an aborted rift below the Xisha Trough with a sub-parallel fossil ridge in the adjacent Northwest Sub-basin. Results from gravity modeling and seismic refraction data show that a high velocity layer (HVL) is present in the outer shelf and slope below extended continental crust in the eastern portion of the northern SCS margin and is thickest (up to 10 km) in the Dongsha Uplift where the HVL gradually thins to east and west below the lower slope and finally terminates at the Manila Trench and Baiyun sag of the Pearl River Mouth Basin. The magmatic intrusions/extrusions and HVL may be related to partial melting caused by decompression of passive, upwelling asthenosphere which resulted primarily in post-rifting underplating and magmatic emplacement or modification of the crust. The northern SCS margin is closer to those of the magma-poor margins than those of volcanic margins, but the aborted rift near the northwestern continental margin shows that there may be no obvious detachment fault like that in the Iberia-Newfoundland type margin. The symmetric aborted

  2. Archaeal diversity in surface sediments of the South China Sea

    NASA Astrophysics Data System (ADS)

    Wang, P.; Wei, Y.; Zhang, C.

    2010-12-01

    The South China Sea is one of the largest marginal seas on Earth and known to be one of the global hot spots of biodiversity. Yet, little is known about the abundance, diversity, and distribution of archaea in it. In this study the diversity and distribution of archaea in the surface sediments of the South China Sea were investigated. The samples were collected from seven sites from south to north of the sea with water depths ranging from 1455 m to 3697 m. Phylogenetic analysis revealed that the relative abundances of Euryarchaeota and Crenarchaeota species (OTUs at 2% cutoff) varied from site to site (Eury: 19.4%-67.6%, Cren: 32.4%-80.6%); however, they were about equal in species distribution (46.9% and 53.1%, respectively) for the total seven archaeal clone libraries. The Crenarchaeota predominates in MD05-2902 and MD05-2904 (80.6% and 70.4%); the Euryarchaeota predominates in MD05-2894 (67.6%). The archaeal groups MGI, MBGB, MCG and SAGMEG were dominant in most of the surface samples. MBGE was only dominant in MD05-2894 (64.7%). Overall, these results indicate that the community structures of archaea vary considerably in the surface sediments of the South China Sea.

  3. Early Continental Rifting of the South China Sea

    NASA Astrophysics Data System (ADS)

    Lee, C.; Chiu, M.; Chan, C.

    2010-12-01

    Combined two years (2007 and 2008) of OBS and MCS studies in the northern slope of the South China Sea, we suggest that the early rifting, probably during 60 - 30 mabp, is an asymmetrical Atlantic-type continental rifting. The crust thin out from 35-40 km of possible continental crust to about 10-15 km of typical oceanic crust. Along the continent-ocean boundary, we observe an intrusion of the high P-wave velocity (about 7.5-8.0 km/sec). This is possible of mantle exhumation as comparable to other Atlantic-type continental margins. The OBS result is revealed by the gravity data. Along the upper layers of the continental crust as well as the oceanic crust, the MCS and multi-beam bathymetry data show that they are covered by numerous submarine seamounts. This probably relate to a volcanic origin of the Cenozoic sea-floor spreading during 30-15 mabp as mapped by previous magnetic anomalies in this region. The sea-floor spreading spread apart in the central, NW and SW sub-basins with several different episodes. Lack of the deep crustal data in the southern slope of the South China Sea, particularly around the Sprately area, the interpretation is speculative. However, several very large-size atolls (150 - 200 km in diameter), such as the Chen-Ho, Shun-Zu, Chung-Yeh and Chiu-Cheng fringing reefs, are sub-parallel located along the south margins. We interpret that these are the upper portions of the continental rifting. Combined the two tectonic stories in the northern and southern slope of the South China Sea, we believe that it is in consistent with the complicate nature of the South China Sea crust.

  4. Lithospheric structure of South China Sea from surface wave tomography

    NASA Astrophysics Data System (ADS)

    Chen, L.; Xue, M.; Le, K.; Yang, T.

    2011-12-01

    The South China Sea is one of the marginal seas of the West Pacific where the Eurasian Plate, Philippine Sea Plate, Pacific Plate and Indo-Australian Plate interact. In this study we give a 3D shear wave velocity structure of South China Sea using surface wave tomographic methods. We use earthquakes distributed on the periphery of the South China Sea and collect the earthquake data from 48 stations (IRIS stations, CDSN stations and four stations deployed in Vietnam by Tongji University) with rays up to ~ 3000. We first calculate the group velocity dispersion curves of fundamental mode for Rayleigh waves with periods from 14 sec to 130 sec using the multiple filter technique. After getting the dispersion curve between each station-to-source pair, we conduct an inversion to get group velocity at each grid point in the rectangular region of 14° s - 34° N and 86° E - 134° E with different grid spacing of 2° × 2° and 1° × 1°. This process is done by the fast marching method as the forward step and then subspace inversion step followed. When we get the group velocity of each grid point for corresponding periods, we can extract a dispersion curve for that point. Through the surface wave inversion which uses Knopoff's calculation method for layered medium as the forward step and the damped least square method as the inversion step followed, we can get an iterative model which carries the information of shear wave velocity and layer depth for each grid point. Finally we put all the shear wave velocity structures of all points together to obtain the three-dimensional shear wave structures. With checkboard tests indicating good resolution, we find that higher group velocities persistently show up in South China Sea Basin, West Philippine Sea Basin, and Celebes Sea Basin from periods of 20 sec to 60 sec, which reflect structures down to 20 - 60 km deep. Similar high shear velocity features also show up in depth slices from 30 km to 60 km. These high shear velocity

  5. China’s Use of Peoples War Theory in the South China Sea

    DTIC Science & Technology

    2017-05-25

    fishermen resulted in strained diplomatic relations between the two countries, 34 Daniel Wagner ...www.huffingtonpost.com/daniel- wagner /china-the- philippines-and_b_1531623.html 35 James Hookway, “Rodrigo Duterte’s China Overtures Appear to Bear Fruit in South...Limits on the Seas” (December 5, 2014). Accessed August 29, 2016. http://www.state.gov/documents/organization/234936.pdf. Wagner , Daniel, Edsel

  6. China’s Energy Insecurity and the South China Sea Dispute

    DTIC Science & Technology

    2011-03-24

    the South China Sea dispute because of the potential influence of Chinese mercantilism on energy resource acquisition, the US, and its regional...that would afford non-member countries SPR protection in the event of an emergency. Such a move could also help discourage Chinese mercantilism by...33 Brzezinski and Mearsheimer, “Clash of the Titans,” 46-50. 34 Wu Lei and Shen Qinyu, “Will China Go to War Over Oil?,” Far Eastern Economic

  7. Population structure and genetic variability of six bar wrasse (Thallasoma hardwicki) in northern South China Sea revealed by mitochondrial control region sequences.

    PubMed

    Chen, Chaolun Allen; Ablan, Maria Carmen Anonuevo; McManus, John Williams; Bell, Johann Diepernk; Tuan, Vo Si; Cabanban, Annadel Sarmiento; Shao, Kwang-Tsao

    2004-01-01

    The genetic relationships among northern South China Sea populations of the six bar wrasse (Thallasoma hardwicki) were investigated. Fish collected from the Solomon Islands were used for geographic comparison. In 1998 and 1999, a total of 100 fish were sampled from 6 localities of the northern South China Sea and 3 localities of the Solomon Islands. Genetic variations in DNA sequences were examined from the first hypervariable region (HVR-1) of the mitochondrial control region, as amplified by polymerase chain reaction. High levels of haplotypic diversity (h = 0.944 +/- 0.0016, pi = 0.0224 +/- 0.01171) in the HVR-1 region of the mitochondrial control region of T. hardwicki were detected. This yielded 94 haplotypes that exhibited a minimum spanning tree with a starburst structure, suggestive of a very recent origin for most haplotypes. Neutrality tests indicated that the pattern of genetic variability in T. hardwicki is consistent either with genetic hitchhiking by an advantageous mutation or with population expansion. Partitioning populations into coherent geographic groups divided the northern South China Sea samples (Phi(CT) = 0.0313, P < 0.001) into 3 major groups: a north-central group composed of northwestern Taiwan and northern Vietnam; a southwestern group containing southern Vietnam; and a southern group including the central Philippines. These results are in concordance with mesoscale boundaries proposed by allozyme markers, thus highlighting the importance of identifying transboundary units for the conservation and management of fisheries in the South China Sea.

  8. Impact of climate change in the Hengduan Mountains of northwestern Yunnan, P.R. China: vegetation distribution change in the foretime and future

    NASA Astrophysics Data System (ADS)

    Sun, Jihua; Baker, Barry; Bachelet, Dominique; Daly, Christopher; Ma, Jian; Liu, Jianyu

    2006-08-01

    Alpine meadows in the Hengduan Mountains of northwestern Yunnan, P.R. China are incredibly diverse. The regional climate is warming at a relatively rapid rate. In this paper, analyses of historical climate station data show that mean annual temperature over the last two decades has increased at a rate of 0.6°C/10 yr. In addition, analyses of historical remote sensing data show that the vegetation distribution in this region has changed evidently. We present simulation results from a general circulation model (HadCM3) and a dynamic vegetation model (MC1) showing how changes in future climate may alter alpine ecosystem of the Baima Nature Reserve in northwestern Yunnan.

  9. Dominant factors in controlling marine gas pools in South China

    USGS Publications Warehouse

    Xu, S.; Watney, W.L.

    2007-01-01

    In marine strata from Sinian to Middle Triassic in South China, there develop four sets of regional and six sets of local source rocks, and ten sets of reservoir rocks. The occurrence of four main formation periods in association with five main reconstruction periods, results in a secondary origin for the most marine gas pools in South China. To improve the understanding of marine gas pools in South China with severely deformed geological background, the dominant control factors are discussed in this paper. The fluid sources, including the gas cracked from crude oil, the gas dissolved in water, the gas of inorganic origin, hydrocarbons generated during the second phase, and the mixed pool fluid source, were the most significant control factors of the types and the development stage of pools. The period of the pool formation and the reconstruction controlled the pool evolution and the distribution on a regional scale. Owing to the multiple periods of the pool formation and the reconstruction, the distribution of marine gas pools was complex both in space and in time, and the gas in the pools is heterogeneous. Pool elements, such as preservation conditions, traps and migration paths, and reservoir rocks and facies, also served as important control factors to marine gas pools in South China. Especially, the preservation conditions played a key role in maintaining marine oil and gas accumulations on a regional or local scale. According to several dominant control factors of a pool, the pool-controlling model can be constructed. As an example, the pool-controlling model of Sinian gas pool in Weiyuan gas field in Sichuan basin was summed up. ?? Higher Education Press and Springer-Verlag 2007.

  10. South China Sea Throughflow Impact on the Indonesian Throughflow

    DTIC Science & Technology

    2012-06-02

    water between 50 and 150 m during the boreal summer. HYCOM output indicates that ENSO induced change of the South China Sea (SCS) throughflow into...sur- face temperature pattern linked to ENSO and the Asian monsoon [Webster et al, 1998; Wajsowicz, 2002]. About 80%, of the ITF ~15 Sv (Sv = 106...contaminated by side lobe reflections from the surface. We have excluded the uppermost 40 m of data to avoid surface contamination effects . We estimate the

  11. POWER AND CULTURE IN THE SOUTH CHINA SEA

    DTIC Science & Technology

    2016-02-16

    AIR WAR COLLEGE AIR UNIVERSITY POWER AND CULTURE IN THE SOUTH CHINA SEA by William S. Denham, Lieutenant Colonel, United States Air Force...Confucian strategic culture and offensive realism, to assess Chinese behavior in three test cases: Paracel Islands in 1974, Fiery Cross Reef and Johnson...China’s historic association with the teaching of Confucius has led some analysts to suggest that the PRC has inherited a strategic culture that

  12. Zircon U-Pb geochronology and geochemistry of two episodes of granitoids from the northwestern Zhejiang Province, SE China: Implication for magmatic evolution and tectonic transition

    NASA Astrophysics Data System (ADS)

    Li, Zilong; Zhou, Jing; Mao, Jianren; Santosh, M.; Yu, Minggang; Li, Yinqi; Hu, Yizhou; Langmuir, Charles H.; Chen, Zhongxing; Cai, Xiongxiang; Hu, Yanhua

    2013-10-01

    Granitoids (175-80 Ma) representing a prominent Yanshanian (Jurassic to Cretaceous) magmatic event in South China widely intrude the Precambrian crystalline basement and Paleozoic strata. Here we report zircon U-Pb age data, geochemical characteristics and Sr-Nd isotopes of the Late Jurassic and Early Cretaceous granitoids from the northwestern Zhejiang Province (ZXB) of southeastern China. Our results reveal two distinct episodes for the Yanshanian magmatism. The Jiemeng and Datongkeng granodiorites formed at 148.6 ± 1.1 Ma, whereas the Huangshitan, Jiuligang and Ruhong aluminous A-type granites were generated between 129.0 ± 0.6 Ma and 126.1 ± 1.1 Ma. The two magmatic phases represent a tectonic transition from an active continental margin to post-orogenic setting during the Late Jurassic (ca. 150 Ma) to Early Cretaceous (ca. 128 Ma). Geochemically, these intrusions are granodioritic to granitic in composition and show an affinity of S-type and A-type granitoids, respectively. The S-type granodiorites of Jiemeng and Datongkeng are characterized by moderate SiO2 (65.0-69.6 wt.%), high K2O + Na2O (5.0-7.6 wt.%), K2O/Na2O (1.2-1.5), Zr (31-109 ppm), Sr (71-190 ppm) and high field strength elements, low to intermediate Mg#, and moderate Nb depletion. The A-type granites of Huangshitan, Jiuligang and Ruhong are characterized by high SiO2 (72.7-77.2 wt.%), K2O + Na2O (6.9-8.8 wt.%), K2O/Na2O (1.3-2.1), FeT/(FeT + Mg), Ga (17-29 ppm, > 20 ppm commonly), Zr (96-197 ppm) and Sr (8-45 ppm) with slight Nb depletion. The S-type granodiorites have higher Mg#, A/NK, Sr, Sr/Ba, Sr/Y, (La/Yb)N, and LREE/HREE, and lower SiO2, K2O + Na2O, Ga and Zr with weak negative Eu anomalies compared to those of the A-type granites with negative Eu anomalies. All these rocks show Y/Nb ratios > 1.2, high initial 87Sr/86Sr (ISr) ratios and low ɛNd(t), and are depleted in Nb, Ti and Sr, indicating crustal origin with subduction zone signatures. We suggested that the ZXB S-type granitic

  13. Eocene Podocarpium (Leguminosae) from South China and its biogeographic implications.

    PubMed

    Xu, Qingqing; Qiu, Jue; Zhou, Zhekun; Jin, Jianhua

    2015-01-01

    Podocarpium A. Braun ex Stizenberger is one of the most common legumes in the Neogene of Eurasia, including fossil fruits, seeds, leaves, and possible flower and pollen grains. This genus is not completely consistent with any extant genera according to gross morphological characters and poorly preserved cuticular structures reported in previous studies. The fossil pods collected from the coal-bearing series of the Changchang Basin of Hainan Island and Maoming Basin of Guangdong, South China, are examined by morphologically comparative work, with special reference to venation patterns and placental position. These distinctive features, as well as the ovule development of pods from different developmental stages and the epidermal structure of the pods, as distinguished from previous records lead to the conclusion that these fossils can be recognized as a new species of Podocarpium, P. eocenicum sp. nov. This new discovery indicates that Podocarpium had arrived in South China by the Eocene. Investigation on the fossil records of this extinct genus shows that P. eocenicum is the earliest and lowest latitude fossil data. The possible occurrence pattern of this genus is revealed as follows: Podocarpium had distributed in the South China at least in the middle Eocene, and then migrated to Europe during the Oligocene; in the Miocene this genus reached its peak in Eurasia, spreading extensively across subtropical areas to warm temperate areas; finally, Podocarpium shrank rapidly and became extinct in Eurasia during the Pliocene.

  14. Eocene Podocarpium (Leguminosae) from South China and its biogeographic implications

    PubMed Central

    Xu, Qingqing; Qiu, Jue; Zhou, Zhekun; Jin, Jianhua

    2015-01-01

    Podocarpium A. Braun ex Stizenberger is one of the most common legumes in the Neogene of Eurasia, including fossil fruits, seeds, leaves, and possible flower and pollen grains. This genus is not completely consistent with any extant genera according to gross morphological characters and poorly preserved cuticular structures reported in previous studies. The fossil pods collected from the coal-bearing series of the Changchang Basin of Hainan Island and Maoming Basin of Guangdong, South China, are examined by morphologically comparative work, with special reference to venation patterns and placental position. These distinctive features, as well as the ovule development of pods from different developmental stages and the epidermal structure of the pods, as distinguished from previous records lead to the conclusion that these fossils can be recognized as a new species of Podocarpium, P. eocenicum sp. nov. This new discovery indicates that Podocarpium had arrived in South China by the Eocene. Investigation on the fossil records of this extinct genus shows that P. eocenicum is the earliest and lowest latitude fossil data. The possible occurrence pattern of this genus is revealed as follows: Podocarpium had distributed in the South China at least in the middle Eocene, and then migrated to Europe during the Oligocene; in the Miocene this genus reached its peak in Eurasia, spreading extensively across subtropical areas to warm temperate areas; finally, Podocarpium shrank rapidly and became extinct in Eurasia during the Pliocene. PMID:26579179

  15. Hydrogeologic framework and groundwater/surface-water interactions of the South Fork Nooksack River Basin, northwestern Washington

    USGS Publications Warehouse

    Gendaszek, Andrew S.

    2014-01-01

    A hydrogeologic framework of the South Fork (SF) Nooksack River Basin in northwestern Washington was developed and hydrologic data were collected to characterize the groundwater-flow system and its interaction with surface‑water features. In addition to domestic, agricultural, and commercial uses of groundwater within the SF Nooksack River Basin, groundwater has the potential to provide ecological benefits by maintaining late-summer streamflows and buffering stream temperatures. Cold-water refugia, created and maintained in part by groundwater, have been identified by water-resource managers as key elements to restore the health and viability of threatened salmonids in the SF Nooksack River. The SF Nooksack River drains a 183-square mile area of the North Cascades and the Puget Lowland underlain by unconsolidated glacial and alluvial sediments deposited over older sedimentary, metamorphic, and igneous bedrock. The primary aquifer that interacts with the SF Nooksack River was mapped within unconsolidated glacial outwash and alluvial sediment. The lower extent of this unit is bounded by bedrock and fine-grained, poorly sorted unconsolidated glaciomarine and glaciolacustrine sediments. In places, these deposits overlie and confine an aquifer within older glacial sediments. The extent and thickness of the hydrogeologic units were assembled from mapped geologic units and lithostratigraphic logs of field-inventoried wells. Generalized groundwater-flow directions within the surficial aquifer were interpreted from groundwater levels measured in August 2012; and groundwater seepage gains and losses to the SF Nooksack River were calculated from synoptic streamflow measurements made in the SF Nooksack River and its tributaries in September 2012. A subset of the field-inventoried wells was measured at a monthly interval to determine seasonal fluctuations in groundwater levels during water year 2013. Taken together, these data provide the foundation for a future groundwater

  16. The variations of stable-carbon isotope ratios in Qilian juniper in northwestern China

    NASA Astrophysics Data System (ADS)

    Zhang, Youfu; Chen, Tuo; An, Lizhe; Li, Youbin

    2007-03-01

    This is the first study of δ13C values that considers elevational influences of the Qilian mountains of China. The δ13C values of different parts of the Qilian juniper ( Sabina przewalskii Kom.) at different elevations of the Qilian mountains, China, were measured. Relatively constant differences in δ13C values existed between the tree leaves and the trunk wood. No strong dependency of δ13C values on elevation was found. The temporal changes of wood δ13C values with directions, elevations and height in the tree showed general similarity. These results suggest that the isotopic effects of environmental factors expressed initially at the site of photosynthesis, i.e., the leaves could be contained in the trunks of a tree. Regardless of elevation, direction or height in the tree, wood δ13C values have been decreasing during the past 60 years. A composite 600-year δ13C chronology developed from four trees showed that δ13C values remain relatively constant before 1800. After 1800 AD, however, δ13C values became significantly more negative. The trend in wood δ13C values was consistent with that obtained for δ13C values in atmospheric CO2. The results showed that for Qilian juniper, tree-ring δ13C chronology could be established to ascertain fluctuations of the atmospheric δ13C.

  17. Black carbon in seasonal snow across northern Xinjiang in northwestern China

    NASA Astrophysics Data System (ADS)

    Ye, Hao; Zhang, Rudong; Shi, Jinsen; Huang, Jianping; Warren, Stephen G.; Fu, Qiang

    2012-12-01

    Black carbon (BC) particles in snow can significantly reduce the snow albedo and enhance the absorption of solar radiation, with important impacts on climate and the hydrological cycle. A field campaign was carried out to measure the BC content in seasonal snow in Qinghai and Xinjiang provinces of western China, in January and February 2012. 284 snow samples were collected at 38 sites, 6 in Qinghai and 32 in Xinjiang. The observational results at the sites in Xinjiang, where the absorbing impurities in snow are dominated by BC particles, are reported in this work. The BC mass fractions in seasonal snow across northern Xinjiang have a median value of ˜70 ng g-1, much lower than those in northeast China. The estimated concentration of BC at the cleanest site in Xinjiang is 20 ng g-1, which is similar to that found along the coast of the Arctic Ocean. It is found that the BC content of snow decreases with altitude. Taking into account this altitude dependence, our measured BC contents in snow are consistent with a recent measurement of BC in winter snow on Tianshan glacier. The data from this field campaign should be useful for testing transport models and climate models for the simulated BC in snow.

  18. Persistent halogenated hydrocarbons in fish feeds manufactured in South China.

    PubMed

    Guo, Ying; Yu, Huan-Yun; Zhang, Bao-Zhong; Zeng, Eddy Y

    2009-05-13

    Persistent halogenated hydrocarbons (PHHs), including organochlorine pesticides (OCPs), polychlorinated biphenyls (PCBs), and polybrominated diphenyl ethers (PBDEs), in fish feeds (including trash fish and compound feed) manufactured in South China, were analyzed. PHHs were ubiquitous in fish feeds, with the concentrations of OCPs, PBDEs, and PCBs at the upper, mid, and lower levels of the global range. Trash fish generally contained higher concentrations of DDXs (sum of o,p'- and p,p'-DDT, -DDD, and -DDE and p,p'-DDMU), especially p,p'-DDT and low-brominated PBDEs, while compound feeds had higher concentrations of highly brominated BDEs, e.g., BDE-209. In addition, no concentration difference of HCHs and PCBs was found between trash fish and compound feeds. The habit of direct use of trash fish as fish feeds has induced the accumulation of DDXs in aquatic species in China, and trash fish collected in South China seemed to be slightly hazardous to wildlife because of the concentrations of DDXs. The results from the present study suggest that the use pattern of fish feeds in China may have to be adjusted to minimize contamination of fishery products and wildlife by PHHs. Use of compound feeds produced with controlled procedures should be encouraged, whereas that of trash fish should be restricted, at least for now.

  19. Cooperation from Strength: The United States, China and the South China Sea

    DTIC Science & Technology

    2012-01-01

    stocks caused by overfishing and lack of authori- tative management. As a result, coastal states gradually gained increasing authority to exercise...tion for access to fisheries in the South China Sea. In particular, overfishing , changing ocean tem- peratures and changing breeding and migration

  20. A synthesis of hydrochemistry with an integrated conceptual model for groundwater in the Hexi Corridor, northwestern China

    NASA Astrophysics Data System (ADS)

    Wang, Liheng; Dong, Yanhui; Xu, Zhifang

    2017-09-01

    Although many studies have investigated the recharge and evolution of groundwater in the Hexi Corridor, northwestern (NW) China, they describe individual sites such as Jinchang, Jiuquan, Dunhuang, and others. Considering the similarity of these sites, a systematic review of the entire Hexi Corridor is lacking. This paper compares and summarizes previous studies in the Hexi Corridor to provide a regional perspective of the isotopic characteristics and hydrochemical composition of groundwater. In unconfined aquifers, groundwater is recharged by snow and ice melt water from the Qilian Mountains; local precipitation can be neglected. Therefore, the groundwater belongs to a unique hydrological cycle model in the Hexi Corridor, referred to as snow and ice melt water-groundwater system. The dominant anion species changes from HCO3- in front of the mountains to SO42- in the middle basin and Cl- at the basin boundary along the groundwater flow direction, and TDS increases gradually owing to evaporation. A major hydrogeochemical process is the dissolution of minerals from the aquifer in the recharge area changing to cation exchange reactions in the discharge area. Confined groundwater was recharged mainly in the late Pleistocene and middle Holocene at colder temperatures than those of modern times; thus, it is non-renewable. In addition to dissolution, the hydrochemical composition of confined groundwater is also affected by cation exchange reactions. The hydrogeochemical categories of the confined groundwater are simple and stable. In the present study, a conceptual model is established on the basis of the analyses presented, which has important implications for water resource management in the Hexi Corridor. The inter-basin water allocation program should continue in order to achieve optimal utilization of water resources, but groundwater exploitation should be limited as much as possible. Additionally, on the basis of the review and integration of previous research, the

  1. A study of variation characteristics of Gobi broadband emissivity based on field observational experiments in northwestern China

    NASA Astrophysics Data System (ADS)

    Zheng, Zhi-yuan; Wei, Zhi-gang; Wen, Zhi-ping; Dong, Wen-jie; Li, Zhen-chao; Wen, Xiao-hang; Zhu, Xian; Chen, Chen; Hu, Shan-shan

    2017-02-01

    Land surface emissivity is a significant variable in energy budgets, land cover assessments, and environment and climate studies. However, the assumption of an emissivity constant is being used in Gobi broadband emissivity (GbBE) parameterization scheme in numerical models because of limited knowledge surrounding the spatiotemporal variation characteristics of GbBE. To address this issue, we analyzed the variation characteristics of GbBE and possible impact factor-surface soil moisture based on long-term continuous and high temporal resolution field observational experiments over a typical Gobi underlying surface in arid and semiarid areas in northwestern China. The results indicate that GbBE has obvious daily and diurnal variation features, especially diurnal cycle characteristics. The multi-year average of the daily average of GbBE is in the range of 0.932 to 0.970 with an average of 0.951 ± 0.008, and the average diurnal GbBE is in the range of 0.880 to 0.940 with an average of 0.906 ± 0.018. GbBE varies with surface soil moisture content. We observed a slight decrease in GbBE with an increase in soil moisture, although this change was not very obvious because of the low soil moisture in this area. Nevertheless, we think that soil moisture must be one of the most significant impact factors on GbBE in arid and semiarid areas. Soil moisture must be taken into account into the parameterization schemes of bare soil broadband emissivity in land surface models. Additional field experiments and studies should be carried out in order to clarify this issue.

  2. A 368-year maximum temperature reconstruction based on tree-ring data in the northwestern Sichuan Plateau (NWSP), China

    NASA Astrophysics Data System (ADS)

    Zhu, Liangjun; Zhang, Yuandong; Li, Zongshan; Guo, Binde; Wang, Xiaochun

    2016-07-01

    We present a reconstruction of July-August mean maximum temperature variability based on a chronology of tree-ring widths over the period AD 1646-2013 in the northern part of the northwestern Sichuan Plateau (NWSP), China. A regression model explains 37.1 % of the variance of July-August mean maximum temperature during the calibration period from 1954 to 2012. Compared with nearby temperature reconstructions and gridded land surface temperature data, our temperature reconstruction had high spatial representativeness. Seven major cold periods were identified (1708-1711, 1765-1769, 1818-1821, 1824-1828, 1832-1836, 1839-1842, and 1869-1877), and three major warm periods occurred in 1655-1668, 1719-1730, and 1858-1859 from this reconstruction. The typical Little Ice Age climate can also be well represented in our reconstruction and clearly ended with climatic amelioration at the late of the 19th century. The 17th and 19th centuries were cold with more extreme cold years, while the 18th and 20th centuries were warm with less extreme cold years. Moreover, the 20th century rapid warming was not obvious in the NWSP mean maximum temperature reconstruction, which implied that mean maximum temperature might play an important and different role in global change as unique temperature indicators. Multi-taper method (MTM) spectral analysis revealed significant periodicities of 170-, 49-114-, 25-32-, 5.7-, 4.6-4.7-, 3.0-3.1-, 2.5-, and 2.1-2.3-year quasi-cycles at a 95 % confidence level in our reconstruction. Overall, the mean maximum temperature variability in the NWSP may be associated with global land-sea atmospheric circulation (e.g., ENSO, PDO, or AMO) as well as solar and volcanic forcing.

  3. Comparing Soil Organic Carbon Dynamics in Perennial Grasses and Shrubs in a Saline-Alkaline Arid Region, Northwestern China

    PubMed Central

    Su, Jiaqi; Zhang, Jingli; Zheng, Yuanrun; Ni, Jian; Xiao, Chunwang; Wang, Renzhong

    2012-01-01

    Background Although semi-arid and arid regions account for about 40% of terrestrial surface of the Earth and contain approximately 10% of the global soil organic carbon stock, our understanding of soil organic carbon dynamics in these regions is limited. Methodology/Principal Findings A field experiment was conducted to compare soil organic carbon dynamics between a perennial grass community dominated by Cleistogenes squarrosa and an adjacent shrub community co-dominated by Reaumuria soongorica and Haloxylon ammodendron, two typical plant life forms in arid ecosystems of saline-alkaline arid regions in northwestern China during the growing season 2010. We found that both fine root biomass and necromass in two life forms varied greatly during the growing season. Annual fine root production in the perennial grasses was 45.6% significantly higher than in the shrubs, and fine root turnover rates were 2.52 and 2.17 yr−1 for the perennial grasses and the shrubs, respectively. Floor mass was significantly higher in the perennial grasses than in the shrubs due to the decomposition rate of leaf litter in the perennial grasses was 61.8% lower than in the shrubs even though no significance was detected in litterfall production. Soil microbial biomass and activity demonstrated a strong seasonal variation with larger values in May and September and minimum values in the dry month of July. Observed higher soil organic carbon stocks in the perennial grasses (1.32 Kg C m−2) than in the shrubs (1.12 Kg C m−2) might be attributed to both greater inputs of poor quality litter that is relatively resistant to decay and the lower ability of microorganism to decompose these organic matter. Conclusions/Significance Our results suggest that the perennial grasses might accumulate more soil organic carbon with time than the shrubs because of larger amounts of inputs from litter and slower return of carbon through decomposition. PMID:22900067

  4. Change in Microbial Community with Salinity in the Sediment of Lake Chaka, a hypersaline lake in Northwestern China

    NASA Astrophysics Data System (ADS)

    Jiang, H.; Yu, B.; Dong, H.; Li, Y.; Zhang, C.

    2005-12-01

    Lake Chaka (36°18'-36°45'N,99°02'-99°12'E), 3800 m above sea level, is located on the Qinghai-Tibetan Plateau, northwestern China, where semi-arid continental climate dominates. The basin of Lake Chaka is about 80 km long and 30 km wide. Strong evaporation and little precipitation (2264 mm evaporation versus 224 mm rainfall/year) in this area have resulted in a nearly dry lake and high salinity (21%). The pH of lake water is 7.4. In November 2004, a sediment core of 10 m in length was collected in Lake Chaka. This sediment core covered a salinity gradient from fresh water at the bottom of the core (10-m depth) to near salt saturation at the surface. Mineralogy also changed with depth, ranging from mud-fine sands at the bottom to mirabilite (Na2SO4) and gypsum in the middle to halite near the top. The biomass determined by acridine orange direct count (AODC) in the sediment core was about 108 cells per gram of wet sample from the bottom to the top. Microbial diversity and community structure as determined by phospholipid fatty acid analysis (PFLA) and 16S rRNA gene analyses in the sediment systematically changed with increasing salinity. Overall, microbial diversity decreased with increasing salinity. At the bottom, freshwater microorganisms are dominant. Near the top of the core, halophilic bacteria and archaea are predominant microorganisms. This systematic change in microbial diversity and community structure is a result of microbial response to progressive increase in salinity in the last 50,000 years.

  5. Crop evapotranspiration-based irrigation management during the growing season in the arid region of northwestern China.

    PubMed

    Chang, Xuexiang; Zhao, Wenzhi; Zeng, Fanjiang

    2015-11-01

    In arid northwestern China, water shortages have triggered recent regulations affecting irrigation water use in desert-oasis agricultural systems. In order to determine the actual water demand of various crops and to develop standards for the rational use of water resources, we analyzed meteorological data from the Fukang desert ecosystem observation and experiment station (FKD), the Cele desert-grassland ecosystem observation and research station (CLD), and the Linze Inland River Basin Comprehensive Research Station (LZD), which all belong to the Chinese Ecosystem Research Network. We researched crop evapotranspiration (ETc) using the water balance method, the FAO-56 Penman-Monteith method, the Priestley-Taylor method, and the Hargreaves method, during the growing seasons of 2005 through 2009. Results indicate substantial differences in ETc, depending on the method used. At the CLD, the ETc from the soil water balance, FAO-56 Penman-Monteith, Priestley-Taylor, and Hargreaves methods were 1150.3±380.8, 783.7±33.6, 1018.3±22.1, and 611.2±23.3 mm, respectively; at the FKD, the corresponding results were 861.0±67.0, 834.2±83.9, 1453.5±47.1, and 1061.0±38.2 mm, respectively; and at the LZD, 823.4±110.4, 726.0±0.4, 722.3±29.4, and 1208.6±79.1 mm, respectively. The FAO-56 Penman-Monteith method provided a fairly good estimation of E Tc compared with the Priestley-Taylor and Hargreaves methods.

  6. Observational study of surface spectral radiation and corresponding albedo over Gobi, desert, and bare loess surfaces in northwestern China

    NASA Astrophysics Data System (ADS)

    Zheng, Z.; Dong, W.; Li, Z.; Zhao, W.; Hu, S.; Yan, X.; Zhao, J.; Wei, Z.

    2015-12-01

    In this paper, the field experiments on ground surface spectral broadband solar radiation (SR) and corresponding albedo were introduced at three man-made sites at Gobi, desert, and bare loess zones during three different intensive observational periods (IOP) from 2010 to 2013 in Gansu Province, respectively. The continuous and high temporal resolution records of ground surface solar radiation are presented, including global (GR), ultraviolet (UV), visible (VIS), and near-infrared radiation (NIR). The corresponding albedos are analyzed over three typical non-vegetated underlying surfaces in arid and semiarid and semihumid regions of northwestern China. The preliminary investigations were carried out. The results show that the variation trends of UV, VIS, and NIR are coincident with the GR, and the irradiances are gradually decreasing throughout the IOP at each site; the energy ratios of VIS/GR are all approximately 40.2%, and the ratios of NIR/GR are all approximately 54.4% at the Gobi, desert, and bare loess zones; and the averaged albedos of the soil for VIS are 0.231, 0.211, and 0.142 and for the NIR are 0.266, 0.252, and 0.255 over the Gobi, desert, and bare loess land surfaces, respectively. The energy ratios of VIS/GR and NIR/GR are not 50% as prescribed for all of the soil color classes in most of land surface models (LSMs). The observational soil albedo values for NIR are not twice to that of the VIS as predicted in some LSMs for the underlying surface at the three sites. GR albedo is determined by the energy ratios of SR/GR and SR albedos.

  7. Observational study of surface spectral radiation and corresponding albedo over Gobi, desert, and bare loess surfaces in northwestern China

    NASA Astrophysics Data System (ADS)

    Zheng, Zhiyuan; Dong, Wenjie; Li, Zhenchao; Zhao, Wei; Hu, Shanshan; Yan, Xiaodong; Zhao, Jiaqi; Wei, Zhigang

    2015-02-01

    In this paper, the field experiments on ground surface spectral broadband solar radiation (SR) and corresponding albedo were introduced at three man-made sites at Gobi, desert, and bare loess zones during three different intensive observational periods (IOP) from 2010 to 2013 in Gansu Province, respectively. The continuous and high temporal resolution records of ground surface solar radiation are presented, including global (GR), ultraviolet (UV), visible (VIS), and near-infrared radiation (NIR). The corresponding albedos are analyzed over three typical nonvegetated underlying surfaces in arid and semiarid and semihumid regions of northwestern China. The preliminary investigations were carried out. The results show that the variation trends of UV, VIS, and NIR are coincident with the GR, and the irradiances are gradually decreasing throughout the IOP at each site; the energy ratios of VIS/GR are all approximately 40.2%, and the ratios of NIR/GR are all approximately 54.4% at the Gobi, desert, and bare loess zones; and the averaged albedos of the soil for VIS are 0.231, 0.211, and 0.142 and for the NIR are 0.266, 0.252, and 0.255 over the Gobi, desert, and bare loess land surfaces, respectively. The energy ratios of VIS/GR and NIR/GR are not 50% as prescribed for all of the soil color classes in most of land surface models (LSMs). The observational soil albedo values for NIR are not twice to that of the VIS as predicted in some LSMs for the underlying surface at the three sites. GR albedo is determined by the energy ratios of SR/GR and SR albedos.

  8. Feasibility of EPS-producing bacterial inoculation to speed up the sand aggregation in the Gurbantunggut Desert, Northwestern China.

    PubMed

    Wu, Nan; Pan, Hui-Xia; Qiu, Dong; Zhang, Yuan-Ming

    2014-12-01

    Exopolymers are known to be useful in improving sand aggregation and the development of biological soil crusts (BSCs). A facultative bacterium KLBB0001 was isolated from BSCs in the Gurbantunggut Desert in northwestern China. With the strong effective production of extracellular polymeric substances (EPS), this strain exhibits a multifunctional role for sand stabilization and maintenance of water under laboratory conditions. Practical testing of the feasibility of its inoculation to speed up BSC recovery in the field was also conducted in this experiment. This strain stimulated the heterotrophic community assembly in the topsoil layer (0-2 cm) before the commencement of autotrophic cyanobacteria, while also significantly increasing the number of bacteria, actinomycetes, and content of total phosphorus, available nitrogen, and available phosphorus. However, the low nitrogenase activity (NA) (0.57 µmol/h) that was observed caused us to doubt the previous identification as Azotobacter Beijerinck that was based on physiological and biochemical properties. A phylogenetic analysis based on 16S rRNA gene sequences revealed that this strain was a member of the genus Paenibacillus. It exhibited the closest phylogenetic affinity and highest sequence similarity to the strain Paenibacillus mucilaginosus VKPM B-7519 (sequence similarity 99.698%), which is well known as a typical silicate-weathering bacteria that releases lots of nutritional ions from minerals and the soil. Because P. mucilaginosus can excrete carbonic anhydrase (CA) to capture atmospheric CO2 through hydration of CO2 , it is possible that KLBB0001 might use a similar strategy for heterotrophs in the BSCs to sequester CO2 from the air. Because of its potential role in the reestablishment of the BSC ecosystem due to its ability to improve water relations, sand stabilization, and chemical erosion, EPS-producing bacterial inoculation was concluded to be a suitable and effective treatment for BSC recovery

  9. The seasonal cycle and variability of sea level in the South China Sea

    NASA Astrophysics Data System (ADS)

    Amiruddin, A. M.; Haigh, I. D.; Tsimplis, M. N.; Calafat, F. M.; Dangendorf, S.

    2015-08-01

    The spatial and temporal characteristics of the seasonal sea level cycle in the South China Sea (SCS) and its forcing mechanisms are investigated using tide gauge records and satellite altimetry observations along with steric and meteorological data. The coastal mean annual amplitude of the seasonal cycle varies between zero and 24 cm, reaching a maximum between July and January. The maximum mean semiannual amplitude is 7 cm, peaking between March and June. Along the coast, the seasonal cycle accounts for up to 92% of the mean monthly sea level variability. Atmospheric pressure explains a significant portion of the seasonal cycle with dominant annual signals in the northern SCS, the Gulf of Thailand and the north-western Philippines Sea. The wind forcing is dominant on the shelf areas of the SCS and the Gulf of Thailand where a simple barotropic model forced by the local wind shows annual amplitudes of up to 27 cm. In the deep basin of the SCS, the Philippines Sea and the shallow Malacca Strait, the steric component is the major contributor with the maximum annual amplitudes reaching 15 cm. Significant variability in the seasonal cycle is found on a year-to-year basis. The annual and semiannual amplitudes vary by up to 63% and 45% of the maximum values, 15 cm and 11 cm, respectively. On average, stepwise regression analysis of contribution of different forcing factors accounts for 66% of the temporal variability of the annual cycle. The zonal wind was found to exert considerable influence in the Malacca Strait.

  10. Ulocladium cantlous sp. nov. isolated from northwestern China: its morphology and molecular phylogenetic position.

    PubMed

    Wang, Yong; Pei, Yun-Fei; O'Neill, Nichole R; Zhang, Xiu-Guo

    2010-01-01

    A new species of Ulocladium was isolated from diseased leaves from two Cucumis sp. growing in Sinkiang and Gansu provinces of China. Conidia were isolated from necrotic leaves and used to establish single-spore pure cultures. Conidia were harvested from cultures 7 d after incubation for morphological comparisons. The morphology of this species resembles that of U. botrytis and U. consortiale. However it is distinguished from these two species by the sizes of obovoid to broadly ellipsoidal conidia and longer conidiophores. A taxonomic description of U. cantlous, comparison with related species in this genus, and a species phylogeny based on the partial nucleotide sequence of the glyceraldehyde-3-phosphate dehydrogenase (gpd) gene and the Alternaria alternata major allergen (Alt a 1) gene are provided.

  11. The South China sea margins: Implications for rifting contrasts

    USGS Publications Warehouse

    Hayes, D.E.; Nissen, S.S.

    2005-01-01

    Implications regarding spatially complex continental rifting, crustal extension, and the subsequent evolution to seafloor spreading are re-examined for the northern and southern-rifted margins of the South China Sea. Previous seismic studies have shown dramatic differences in the present-day crustal thicknesses as the manifestations of the strain experienced during the rifting of the margin of south China. Although the total crustal extension is presumed to be the same along the margin and adjacent ocean basin, the amount of continental crustal extension that occurred is much less along the east and central segments of the margin than along the western segment. This difference was accommodated by the early formation of oceanic crust (creating the present-day South China Sea basin) adjacent to the eastern margin segment while continued extension of continental crust was sustained to the west. Using the observed cross-sectional areas of extended continental crust derived from deep penetration seismics, two end-member models of varying rift zone widths and varying initial crustal thicknesses are qualitatively examined for three transects. Each model implies a time difference in the initiation of seafloor spreading inferred for different segments along the margin. The two models examined predict that the oceanic crust of the South China Sea basin toward the west did not begin forming until sometime between 6-12 my after its initial formation (???32 Ma) toward the east. These results are compatible with crustal age interpretations of marine magnetic anomalies. Assuming rifting symmetry with conjugate margin segments now residing along the southern portions of the South China Sea basin implies that the total width of the zone of rifting in the west was greater than in the east by about a factor of two. We suggest the most likely causes of the rifting differences were east-west variations in the rheology of the pre-rift crust and associated east-west variations in the

  12. A toxicological study of inhalable particulates in an industrial region of Lanzhou City, northwestern China: Results from plasmid scission assay

    NASA Astrophysics Data System (ADS)

    Xiao, Zhenghui; Shao, Longyi; Zhang, Ning; Wang, Jing; Chuang, Hsiao-Chi; Deng, Zhenzhen; Wang, Zhen; BéruBé, Kelly

    2014-09-01

    The city of Lanzhou in northwestern China experiences serious air pollution episodes in the form of PM10 that is characterized by having high levels of heavy metals. The Xigu District represents the industrial core area of Lanzhou City and is denoted by having the largest petrochemical bases in western China. This study investigates heavy metal compositions and oxidative potential of airborne PM10 (particulate matter with aerodynamic diameter of 10 μm or less) collected in Xigu District in the summer and winter of 2010. An in vitro plasmid scission assay (PSA) was employed to study the oxidative potential of airborne PM10 and inductively coupled plasma-mass spectrometry (ICP-MS) was used to examine heavy metal compositions. Transmission electron microscopy coupled with energy-dispersive X-ray spectrometry (TEM/EDX) was used to investigate elemental compositions and mixing states of PM10. The average mass concentrations of PM10 collected in Xigu District were generally higher than the national standard for daily PM10 (150 μg/m3). Cr, Zn, Pb and Mn were the most abundant metals in the intact whole particles of PM10. Zn, Mn and As was the most abundant metal in the water-soluble fraction, while Cr, Pb, and V existed primarily in insoluble forms. TD20 values (i.e. toxic dosage of PM10 causing 20% of plasmid DNA damage) varied considerably in both winter and summer (from 19 μg/mL to >1000 μg/mL) but were typically higher in summer, suggesting that the winter PM10 exhibited greater bioreactivity. In addition, the PM10 collected during a dust storm episode had a highest TD20 value and thus the least oxidative damage to supercoiled plasmid DNA, while the particles collected on a hazy day had a lowest TD20 value and thus the highest oxidative damage to supercoiled plasmid DNA. The particles collected on the first day after snow fall and on a day of cold air intrusion exhibited minor oxidative potential (i.e. caused limited DNA damage). The water-soluble Zn, Mn, As, and

  13. New species of the giant deep-sea isopod genus Bathynomus (Crustacea, Isopoda, Cirolanidae) from Hainan Island, South China Sea.

    PubMed

    Kou, Qi; Chen, Jun; Li, Xinzheng; He, Lisheng; Wang, Yong

    2017-07-01

    Several specimens of the giant deep-sea isopod genus Bathynomus were collected by a deep-sea lander at a depth of 898 m near Hainan Island in the northern South China Sea. After careful examination, this material and the specimens collected from the Gulf of Aden, north-western Indian Ocean, previously reported as Bathynomus sp., were identified to be the same as a new species to the genus. Bathynomus jamesi sp. nov. can be distinguished from the congeners by: the distal margin of pleotelson with 11 or 13 short straight spines and central spine not bifid; uropodal endopod and exopod with distolateral corner slightly pronounced; clypeus with lateral margins concave; and antennal flagellum extending when extended posteriorly reaches the pereonite 3. In addition, Bathynomus jamesi sp. nov. is also supported by molecular analyses based on mitochondrial COI and 16S rRNA gene sequences. The distribution range of the new species includes the western Pacific and north-western Indian Ocean. © 2017 International Society of Zoological Sciences, Institute of Zoology/Chinese Academy of Sciences and John Wiley & Sons Australia, Ltd.

  14. China-South Korea Relations: Elder Brother Wins Over Younger Brother

    DTIC Science & Technology

    2004-10-01

    the most important impact on the future of Korea . ● Many South Koreans welcome increased Chinese influence in the region and on the Korean Peninsula as...largely successful in persuading South Koreans not to consider China a “threat” either economically or strategically. ● China-South Korea relations are...show to Beijing. The logical conclusion of these trends would be Korean accommodation of China and the end of the U.S.- Korea alliance. ● Nevertheless

  15. A fall land bird migration across the South China Sea from Indo-China to the Greater Sunda Islands

    USGS Publications Warehouse

    Ellis, D.H.; Kepler, A.K.; Kepler, C.B.

    1994-01-01

    We encountered 150 land birds representing 14 families along the cruise track of the Soviet Oceanographic Research Vessel AKADEMlK KOROLEV in the South China Sea. We saw most of these birds during a 3 -day period in a small area c. 350 km southeast of the southern tip of the Indo-China peninsula. These observations suggest that a significant land bird migration corridor crosses the South China Sea from Viet Nam to Borneo.

  16. Comparisons of Three Methods for Organic and Inorganic Carbon in Calcareous Soils of Northwestern China

    PubMed Central

    Wang, Xiujun; Wang, Jiaping; Zhang, Juan

    2012-01-01

    With increasing interest in the carbon cycle on arid land, there is an urgent need to quantify both soil organic carbon (SOC) and inorganic carbon (SIC) thus to assess various methods. Here, we present a study employing three methods for determinations of SOC and SIC in the Yanqi Basin of northwest China. We use an elemental analyzer for both SOC and SIC, the Walkley-Black method for SOC, a modified pressure calcimeter method for SIC, and a simple loss-on-ignition (LOI) procedure for determinations of SOC and SIC. Our analyses show that all three approaches produce consistently low values for SOC (1–14 g kg−1) and high values for SIC (8–53 g kg−1). The Walkley-Black method provides an accurate estimate of SOC with 100% recovery for most soil samples. The pressure calcimeter method is as accurate as the elemental analysis for measuring SIC. In addition, SOC and SIC can be accurately estimated using a two-step LOI approach, i.e., (1) combustion at 375°C for 17 hours to estimate SOC, and (2) subsequent combustion at 800°C for 12 hours to estimate SIC. There are strong linear relationships for both SOC and SIC between the elemental analysis and LOI method, which demonstrates the capability of the two-step LOI technique for estimating SOC and SIC in this arid region. PMID:22952957

  17. Historical ruins of remote sensing archaeology in arid desertified environment, northwestern China

    NASA Astrophysics Data System (ADS)

    Hu, N. K.; Li, X.

    2017-02-01

    Silk Road is an important exchange channel for human communication and culture propagation between ancient China and the West during historical periods. A lot of human activities performed in Silk Road and many historical ruins leave behind to present. Archaeological ruins can play a significant role in studying and restoring the past human activities, as well as understanding regional environmental changes. There were many flourishingly human activities during different historical periods that were developed in ancient Juyan Oasis in the downstream of the Heihe River Basin. A large number of historical ruins that reflect past human activities preserved between numerous of the nebkhas and sand dunes. In this study, combined high-resolution remote sensing imageries with in situ truths investigated during the fieldwork, certain unknown ruins were identified according to the image features of historical ruins that appear in remotely sensed data, which were undiscovered during the previous field archaeological investigations and unreported in the past public literatures. Almost all of the newly discovered ruins that were identified using remote sensing images are distributed in the Lvcheng and BJ2008 surroundings. Newly findings supplement the missing gaps that were not taking into account during the previous field surveys.

  18. Microbial Diversity in Water and Sediment of Lake Chaka, an Athalassohaline Lake in Northwestern China

    PubMed Central

    Jiang, Hongchen; Dong, Hailiang; Zhang, Gengxin; Yu, Bingsong; Chapman, Leah R.; Fields, Matthew W.

    2006-01-01

    We employed culture-dependent and -independent techniques to study microbial diversity in Lake Chaka, a unique hypersaline lake (32.5% salinity) in northwest China. It is situated at 3,214 m above sea level in a dry climate. The average water depth is 2 to 3 cm. Halophilic isolates were obtained from the lake water, and halotolerant isolates were obtained from the shallow sediment. The isolates exhibited resistance to UV and gamma radiation. Microbial abundance in the sediments ranged from 108 cells/g at the water-sediment interface to 107 cells/g at a sediment depth of 42 cm. A major change in the bacterial community composition was observed across the interface. In the lake water, clone sequences affiliated with the Bacteroidetes were the most abundant, whereas in the sediments, sequences related to low G+C gram-positive bacteria were predominant. A similar change was also present in the archaeal community. While all archaeal clone sequences in the lake water belonged to the Halobacteriales, the majority of the sequences in the sediments were related to those previously obtained from methanogenic soils and sediments. The observed changes in the microbial community structure across the water-sediment interface were correlated with a decrease in salinity from the lake water (32.5%) to the sediments (approximately 4%). Across the interface, the redox state also changed from oxic to anoxic and may also have contributed to the observed shift in the microbial community. PMID:16751487

  19. Crustal and upper-mantle structure of South China from Rayleigh wave tomography

    NASA Astrophysics Data System (ADS)

    Shan, B.; Xiong, X.; Zhao, K. F.; Xie, Z. J.; Zheng, Y.; Zhou, L.

    2017-03-01

    In this study, we image the crust and upper-mantle seismic velocity structures in South China using teleseismic Rayleigh waves recorded at 354 stations from the Chinese provincial networks (CEArray). We process Rayleigh wave data from 1087 teleseismic events and construct phase velocity maps at periods of 40-150 s. By combining dispersion curves at 6-70 s from Zhou et al. and at 40-150 s from the teleseismic surface wave tomography of this study, we construct a 3-D shear velocity model of the crust and upper mantle of South China. Distinct seismic structures are revealed from the eastern part of South China (including the South China Fold System and the eastern Yangtze Craton) to the western Yangtze Craton. The South China Fold System and eastern Yangtze Craton are characterized by lower velocities and shallow lithosphere-asthenosphere boundary (∼90 km), which are similar to the lithospheric thermal and seismic velocity structures of the North China basin. These observations may imply that the lithospheric destruction and thinning occurred not only beneath the North China Craton, but also beneath the eastern part of South China. The western Yangtze Craton, including the Sichuan Basin and Jiangnan Orogen, is underlain by a thicker and colder lithosphere with high velocities. The contrast of the lithosphere structure between the western Yangtze Craton and other parts of South China indicates that the lithospheric destruction and thinning of the east and southeast parts of South China may terminate at the boundary of the Jiangnan Orogen.

  20. Measurement of scattering and absorption properties of dust aerosol in a Gobi farmland region of northwestern China - a potential anthropogenic influence

    NASA Astrophysics Data System (ADS)

    Bi, Jianrong; Huang, Jianping; Shi, Jinsen; Hu, Zhiyuan; Zhou, Tian; Zhang, Guolong; Huang, Zhongwei; Wang, Xin; Jin, Hongchun

    2017-06-01

    We conducted a comprehensive field campaign to explore the optical characteristics of mineral dust in Dunhuang farmland near the Gobi Desert of northwest China during spring of 2012. The day-to-day and diurnal variations of dust aerosol showed prominent features throughout the experiment, primarily attributable to frequent dust events and local anthropogenic emissions. The overall average mass concentrations of the particulate matter with an aerodynamic diameter less than 10 µm (PM10), light scattering coefficient (σsp, 670), absorption coefficient (σap, 670), and single-scattering albedo (SSA670) were 113 ± 169 µg m-3, 53.3 ± 74.8 Mm-1, 3.2 ± 2.4 Mm-1, and 0.913 ± 0.05, respectively, which were comparable to the background levels in the southern United States but smaller than those in the eastern and other northwestern Chinese cities. The anthropogenic dust produced by agricultural cultivations (e.g., land planning, plowing, and disking) exerted a significant superimposed effect on high dust concentrations in Dunhuang farmland prior to the growing season (i.e., from 1 April to 10 May). Strong south valley wind and vertical mixing in daytime scavenged the pollution, and the weak northeast mountain wind and stable inversion layer at night favorably accumulated the air pollutants near the surface. In the afternoon (13:00-18:00 LT, local time), mean SSA670 was 0.945 ± 0.04 predominantly from dust particles, whereas finer particles and lower SSA670 values ( ˜ 0.90-0.92) were measured at night, suggesting the potential influence by the mixed dust pollutants. During a typical biomass burning event on 4 April 2012, σap, 670 increased from ˜ 2.0 to 4.75 Mm-1 and SSA670 changed from ˜ 0.90 to ˜ 0.83, implying remarkable modification of aerosol absorptive properties induced by human activities. The findings of this study would help to advance an in-depth understanding of the interaction among dust aerosol, atmospheric chemistry, and climate change in a desert

  1. Comparative homegarden medical ethnobotany of Naxi healers and farmers in Northwestern Yunnan, China.

    PubMed

    Yang, Lixin; Ahmed, Selena; Stepp, John Richard; Mi, Kai; Zhao, Yanqiang; Ma, Junzeng; Liang, Chen; Pei, Shengji; Huai, Huyin; Xu, Gang; Hamilton, Alan C; Yang, Zhi-wei; Xue, Dayuan

    2014-01-10

    Homegardens are ecologically and culturally important systems for cultivating medicinal plants for wellbeing by healers and farmers in Naxi communities of the Sino Himalayan region. The cultivation of medicinal plants in Naxi communities and associated ethnomedical knowledge base for maintaining and utilizing these resources is at risk with expanded commercialization of natural resources, development policies and rapid socio-economic change in China. Research is needed to understand the medicinal plant species maintained in Naxi homegardens, their use and contribution to community wellbeing, and how these practices and knowledge base varies between Naxi healers and farmers in order to develop plans for biodiversity conservation and preservation of ethnomedical practices. The main objective of this study is to document and compare medicinal plant species in Naxi homegardens and associated ethnomedical knowledge between Naxi healers and farmers. Ethnobotanical homegarden surveys were conducted with three Naxi healers and 28 farmer households in two Naxi communities in Lijiang Prefecture in Northwest Yunnan Province of China. Surveys included inventories of medicinal plants in homegardens and semi-structured interviews with homegarden managers to document traditional medicinal uses of inventoried plants. Inventoried plants were classified into 13 'usage categories' of medical condition groupings that impact a system of the body. Finally, plant species richness was calculated for each homegarden and species richness was compared between healers and farmers as well as between study sites using a Least Square Means Tukey HSD function. Ethnobotanical surveys at the study sites found that 13% of households rely exclusively on traditional Naxi medicine, 26% exclusively use Western medicine and 61% use a combination of traditional Naxi and Western medicine. A total of 106 medicinal plants were inventoried in Naxi homegardens representing 50 botanical families. Over 85% of

  2. Comparative homegarden medical ethnobotany of Naxi healers and farmers in Northwestern Yunnan, China

    PubMed Central

    2014-01-01

    Background Homegardens are ecologically and culturally important systems for cultivating medicinal plants for wellbeing by healers and farmers in Naxi communities of the Sino Himalayan region. The cultivation of medicinal plants in Naxi communities and associated ethnomedical knowledge base for maintaining and utilizing these resources is at risk with expanded commercialization of natural resources, development policies and rapid socio-economic change in China. Research is needed to understand the medicinal plant species maintained in Naxi homegardens, their use and contribution to community wellbeing, and how these practices and knowledge base varies between Naxi healers and farmers in order to develop plans for biodiversity conservation and preservation of ethnomedical practices. The main objective of this study is to document and compare medicinal plant species in Naxi homegardens and associated ethnomedical knowledge between Naxi healers and farmers. Methods Ethnobotanical homegarden surveys were conducted with three Naxi healers and 28 farmer households in two Naxi communities in Lijiang Prefecture in Northwest Yunnan Province of China. Surveys included inventories of medicinal plants in homegardens and semi-structured interviews with homegarden managers to document traditional medicinal uses of inventoried plants. Inventoried plants were classified into 13 ‘usage categories’ of medical condition groupings that impact a system of the body. Finally, plant species richness was calculated for each homegarden and species richness was compared between healers and farmers as well as between study sites using a Least Square Means Tukey HSD function. Results Ethnobotanical surveys at the study sites found that 13% of households rely exclusively on traditional Naxi medicine, 26% exclusively use Western medicine and 61% use a combination of traditional Naxi and Western medicine. A total of 106 medicinal plants were inventoried in Naxi homegardens representing 50

  3. Changes in Remotely Sensed Vegetation Growth Trend in the Heihe Basin of Arid Northwestern China

    PubMed Central

    Yao, Xiaolei; Ishidaira, Hiroshi; Xu, Zongxue

    2015-01-01

    The Heihe River Basin (HRB) is the second largest inland river basin in China, characterized by high diversity in geomorphology and irrigated agriculture in middle reaches. To improve the knowledge about the relationship between biotic and hydrological processes, this study used Global Inventory Modeling and Mapping Studies Normalized Difference Vegetation Index (NDVI) data (1982–2006) to analyze spatiotemporal variations in vegetation growth by using the Mann—Kendall test together with Sen’s slope estimator. The results indicate that 10.1% and 1.6% of basin area exhibit statistically significant (p < 0.05) upward and downward trends, and maximum magnitude is 0.066/10a and 0.026/10a, respectively. More specifically, an increasing trend was observed in the Qilian Mountains and Hexi Corridor and a decreasing trend detected in the transitional region between them. Increases in precipitation and temperature may be one possible reason for the changes of vegetation growth in the Qilian Mountains. And decreasing trend in transitional region may be driven by the changes in precipitation. Increases of irrigation contribute to the upward trend of NDVI for cropland in the Hexi Corridor, reflecting that agricultural development becomes more intensive. Our study demonstrates the complexity of the response of vegetation growth in the HRB to climate change and anthropogenic activities and correspondingly adopting mechanistic ecological models capable of describing both factors is favorable for reasonable predictions of future vegetation growth. It is also indicated that improving irrigation water use efficiency is one practical strategy to balance water demand between human and natural ecosystems in the HRB. PMID:26284656

  4. Carbon and nitrogen contents in Desert Plants and Soil in the Yanqi basin of Northwestern China

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Wang, X.; Wang, J.

    2011-12-01

    Carbon and nitrogen are two main elements in plant-soil systems. Here, we present a study of carbon and nitrogen contents in several typical desert plants and underlying soil, which was conducted in Yanqi basin, Xinjiang province of China. Our results show that carbon (C) content is around 30% in both aboveground tissues and belowground roots. Nitrogen (N) content in desert plants has a range of 0.5%-3.5%, and the aboveground tissue has higher nitrogen content (~2%) than the belowground root (~1%). As a result, the belowground root has higher C/N ratio (~35) than the aboveground tissue (~25). Especially, the C/N values in belowground roots are twice as much as their aboveground tissues in Acroption repens, Tamarix ramosissima Ledeb. and Halostachys caspica. In desert soils, the contents of soil organic carbon (SOC), total nitrogen (TN) with depth 0-50cm are range of 12.5-4.6 and 3.2-1.4 g/kg, respectively, different . As expected, the SOC and TN contents are declined with the depth increase. Meanwhile, our result indicated the soil TN is followed the SOC dynamic, as both elements are bond into the organic compounds. However, unlike the C/N ratios in aboveground tissue and roots, there is no significant difference of C/N ratios (2.95-3.46) in the soils within the 0-50 cm depth. The results inferred that in the desert plant C mainly storage in roots, but the C, N allocation between desert plant and soil has no significantly related.

  5. Changes in Remotely Sensed Vegetation Growth Trend in the Heihe Basin of Arid Northwestern China.

    PubMed

    Sun, Wenchao; Song, Hao; Yao, Xiaolei; Ishidaira, Hiroshi; Xu, Zongxue

    2015-01-01

    The Heihe River Basin (HRB) is the second largest inland river basin in China, characterized by high diversity in geomorphology and irrigated agriculture in middle reaches. To improve the knowledge about the relationship between biotic and hydrological processes, this study used Global Inventory Modeling and Mapping Studies Normalized Difference Vegetation Index (NDVI) data (1982-2006) to analyze spatiotemporal variations in vegetation growth by using the Mann-Kendall test together with Sen's slope estimator. The results indicate that 10.1% and 1.6% of basin area exhibit statistically significant (p < 0.05) upward and downward trends, and maximum magnitude is 0.066/10a and 0.026/10a, respectively. More specifically, an increasing trend was observed in the Qilian Mountains and Hexi Corridor and a decreasing trend detected in the transitional region between them. Increases in precipitation and temperature may be one possible reason for the changes of vegetation growth in the Qilian Mountains. And decreasing trend in transitional region may be driven by the changes in precipitation. Increases of irrigation contribute to the upward trend of NDVI for cropland in the Hexi Corridor, reflecting that agricultural development becomes more intensive. Our study demonstrates the complexity of the response of vegetation growth in the HRB to climate change and anthropogenic activities and correspondingly adopting mechanistic ecological models capable of describing both factors is favorable for reasonable predictions of future vegetation growth. It is also indicated that improving irrigation water use efficiency is one practical strategy to balance water demand between human and natural ecosystems in the HRB.

  6. Characterization of Pu concentration and its isotopic composition in soils of Gansu in northwestern China.

    PubMed

    Zheng, Jian; Yamada, Masatoshi; Wu, Fengchang; Liao, Haiqing

    2009-01-01

    The total 239+240Pu activities and 240Pu/239Pu atom ratios in surface soil samples (0-5cm) in the Kumtag Desert in western Gansu Province, and in a soil core sample in Lanzhou were investigated using a sector-field ICP-MS. In the surface soil samples, 239+240Pu activities in fine particles (<150microm) were 1.3-2.1 times of those in coarse particles (150microm-1mm) which ranged from 0.005 to 0.157mBq/g. Atom ratios of 240Pu/239Pu in the surface soils ranged from 0.168 to 0.192 with a mean of 0.182+/-0.008. The mean ratio was similar to the typical global fallout value although the Kumtag Desert was believed to have received close-in fallout derived from Chinese nuclear weapons tests mainly conducted in the 1970s. Furthermore, the mean 240Pu/239Pu atom ratio observed in the soil core sample in Lanzhou was similar to the typical global fallout value. In the soil core sample, 239+240Pu activities in the various layers ranged from 0.012 to 0.23mBq/g, and the inventory of 239+240Pu (32.4Bq/m2, 0-23cm) was slightly lower than that expected from global fallout (42Bq/m2) at the same latitude. Rapid downward migration of Pu isotopes was observed in Lanzhou soil core sample layers. The contribution of the 10-cm deep top layers of surface soils to total inventory was only 17%, while the contribution of deeper layers (10-23cm) was as high as 83%. The 239+240Pu activity levels and 240Pu/239Pu atom ratios in soils in Gansu Province, China are similar to those in atmospheric deposition samples collected in the spring in recent years in Japan.

  7. Using Google Trends for influenza surveillance in South China.

    PubMed

    Kang, Min; Zhong, Haojie; He, Jianfeng; Rutherford, Shannon; Yang, Fen

    2013-01-01

    Google Flu Trends was developed to estimate influenza activity in many countries; however there is currently no Google Flu Trends or other Internet search data used for influenza surveillance in China. Influenza surveillance data from 2008 through 2011 were obtained from provincial CDC influenza-like illness and virological surveillance systems of Guangdong, a province in south China. Internet search data were downloaded from the website of Google Trends. Pearson's correlation coefficients with 95% confidence intervals (95% CI) were calculated to compare surveillance data and internet search trends. The correlation between CDC ILI surveillance and CDC virus surveillance was 0.56 (95% CI: 0.43, 0.66). The strongest correlation was between the Google Trends term of Fever and ILI surveillance with a correlation coefficient of 0.73 (95% CI: 0.66, 0.79). When compared with influenza virological surveillance, the Google Trends term of Influenza A had the strongest correlation with a correlation coefficient of 0.64 (95% CI: 0.43, 0.79) in the 2009 H1N1 influenza pandemic period. This study shows that Google Trends in Chinese can be used as a complementary source of data for influenza surveillance in south China. More research in the future should develop new models using search trends in Chinese language to estimate local disease activity and detect early signals of outbreaks.

  8. Spatial variability and stocks of soil organic carbon in the Gobi desert of Northwestern China.

    PubMed

    Zhang, Pingping; Shao, Ming'an

    2014-01-01

    Soil organic carbon (SOC) plays an important role in improving soil properties and the C global cycle. Limited attention, though, has been given to assessing the spatial patterns and stocks of SOC in desert ecosystems. In this study, we quantitatively evaluated the spatial variability of SOC and its influencing factors and estimated SOC storage in a region (40 km2) of the Gobi desert. SOC exhibited a log-normal depth distribution with means of 1.6, 1.5, 1.4, and 1.4 g kg(-1) for the 0-10, 10-20, 20-30, and 30-40 cm layers, respectively, and was moderately variable according to the coefficients of variation (37-42%). Variability of SOC increased as the sampling area expanded and could be well parameterized as a power function of the sampling area. Significant correlations were detected between SOC and soil physical properties, i.e. stone, sand, silt, and clay contents and soil bulk density. The relatively coarse fractions, i.e. sand, silt, and stone contents, had the largest effects on SOC variability. Experimental semivariograms of SOC were best fitted by exponential models. Nugget-to-sill ratios indicated a strong spatial dependence for SOC concentrations at all depths in the study area. The surface layer (0-10 cm) had the largest spatial dependency compared with the other layers. The mapping revealed a decreasing trend of SOC concentrations from south to north across this region of the Gobi desert, with higher levels close to an oasis and lower levels surrounded by mountains and near the desert. SOC density to depths of 20 and 40 cm for this 40 km2 area was estimated at 0.42 and 0.68 kg C m(-2), respectively. This study provides an important contribution to understanding the role of the Gobi desert in the global carbon cycle.

  9. Spatial Variability and Stocks of Soil Organic Carbon in the Gobi Desert of Northwestern China

    PubMed Central

    Zhang, Pingping; Shao, Ming'an

    2014-01-01

    Soil organic carbon (SOC) plays an important role in improving soil properties and the C global cycle. Limited attention, though, has been given to assessing the spatial patterns and stocks of SOC in desert ecosystems. In this study, we quantitatively evaluated the spatial variability of SOC and its influencing factors and estimated SOC storage in a region (40 km2) of the Gobi desert. SOC exhibited a log-normal depth distribution with means of 1.6, 1.5, 1.4, and 1.4 g kg−1 for the 0–10, 10–20, 20–30, and 30–40 cm layers, respectively, and was moderately variable according to the coefficients of variation (37–42%). Variability of SOC increased as the sampling area expanded and could be well parameterized as a power function of the sampling area. Significant correlations were detected between SOC and soil physical properties, i.e. stone, sand, silt, and clay contents and soil bulk density. The relatively coarse fractions, i.e. sand, silt, and stone contents, had the largest effects on SOC variability. Experimental semivariograms of SOC were best fitted by exponential models. Nugget-to-sill ratios indicated a strong spatial dependence for SOC concentrations at all depths in the study area. The surface layer (0–10 cm) had the largest spatial dependency compared with the other layers. The mapping revealed a decreasing trend of SOC concentrations from south to north across this region of the Gobi desert, with higher levels close to an oasis and lower levels surrounded by mountains and near the desert. SOC density to depths of 20 and 40 cm for this 40 km2 area was estimated at 0.42 and 0.68 kg C m−2, respectively. This study provides an important contribution to understanding the role of the Gobi desert in the global carbon cycle. PMID:24733073

  10. A potential submarine landslide tsunami in South China Sea

    NASA Astrophysics Data System (ADS)

    Huang, Z.; Zhang, Y.; Switzer, A. D.

    2010-12-01

    Submarine earthquakes and submarine landslides are two main sources of tsunamis. Tsunami hazard modeling in the South China Sea has been primarily concerned with the potential large submarine earthquakes in the Manila trench. In contrast, evaluating the regional risk posed by tsunamis generated from submarine landslide is a new endeavor. At offshore south central Vietnam, bathymetric and seismic surveys show evidence of potentially tsunamigenic submarine landslides although their ages remain uncertain. We model two hypothetical submarine landslide events at a potential site on the heavily sediment laden, seismically active, steep continental slope offshore southeast Vietnam. Water level rises along the coast of Vietnam are presented for the potential scenarios, which indicate that the southeast coastal areas of Vietnam are at considerable risk of tsunami generated offshore submarine landslides. Key references: Kusnowidjaja Megawati, Felicia Shaw, Kerry Sieh, Zhenhua Huang, Tso-Ren Wu, Y. Lin, Soon Keat Tan and Tso-Chien Pan.(2009). Tsunami hazard from the subduction megathrust of the South China Sea, Part I, Source characterization and the resulting tsunami, Journal of Asian Earth Sciences, Vol. 36(1), pp. 13-20. Enet, F., Grilli, S.T. and Watts, P. (2003). Laboratory experiments for tsunami generated by underwater landslides: comparison with numerical modeling, In: Proceedings of 13th International Conference on Offshore and Polar Engineering, Honolulu, Hawaii, USA, pp. 372-379.

  11. Euxinia prior to end-Permian main extinction at Xiaojiaba section, Sichuan Province, South China

    NASA Astrophysics Data System (ADS)

    Wei, H.; Algeo, T. J.; Chen, D.; Yu, H.

    2013-12-01

    Redox conditions in the global ocean prior to, during, and following the end-Permian mass extinction at 252.28 Ma remain contentious. Previous studies in western Australia, South China, and East Greenland have shown that photic-zone euxinia was present at least intermittently from the early Changhsingian through the Dienerian1-3. Here we report a study of organic carbon isotopes, pyrite sulfur isotopes, TOC, pyritic sulfur content, REE, and major and trace elements from the Upper Permian Xiaojiaba section in the Chaotian district of Guangyuan City, Sichuan Province, China. During the Permian-Triassic transition, this section was located on the northwestern margin of the South China Block, facing the Paleo-Tethys Ocean. Our results indicate that suboxic conditions prevailed during the Wuchiapingian and suboxic to anoxic conditions with several pulses of euxinia during the Changhsingian. δ13Corg values are mostly -28‰ to -26‰ but show three positive excursions (to -22‰) prior to the end-Permian mass extinction horizon. These positive excursions are associated with higher Spy concentrations (to ~1%). δ34Spy values are variable (from -41‰ to +5‰) but show a sharp negative excursion in the late Changhsingian (to -43.4‰) that coincided with the most positive δ13Corg values. This horizon is also associated with increases in Eu/Eu*, Baxs, ∑REE, Si, and redox-sensitive metals such as V. These patterns reflect linkage of the C and S cycles during the latest Permian, possibly in response to redox controls. The observed positive excursions in δ13Corg may be due to organic inputs from green sulfur bacteria, which exhibit a smaller photosynthetic fractionation (-12.5‰4) than eukaryotic algae. The pronounced negative excursion of δ34Spy corresponds to a sulfate-sulfide S isotope fractionation of about -60‰, suggesting a large flux of syngenetic framboidal pyrite, which would be indicative of euxinic water-column conditions. We infer that the euxinia prior

  12. The tectonic evolution of the greater South China Sea

    SciTech Connect

    Hayes, D.E. )

    1990-06-01

    The South China Sea (SCS) basin is composed of two major subbasins. The eastern subbasin was formed by seafloor spreading in the middle Tertiary and is associated with roughly E-W-trending magnetic lineations. The southwestern subbasin of the South China Sea is characterized by NE-SW tectonic and magnetic trends and is considerably narrower than the eastern subbasin. There is no obvious structural discontinuity between the two subbasins; hence the initial opening of the eastern subbasin was likely accommodated to the west by a prolonged period of extension of the continental crust that was not accompanied by the formation of normal oceanic crust. The southwest subbasin was eventually also formed by seafloor spreading processes. Although the sequence of magnetic lineations recorded there is relatively short, these data coupled with heatflow and crustal depth data strongly suggest that the southwestern subbasin was not formed until the early-middle Miocene, coincident with the last phase of spreading in the adjacent eastern subbasin. It is still unclear whether or not a significant change in spreading direction occurred within the SCS basin during the early Miocene. The geometry of the deep SCS basin as defined by the seaward limit of the continent-ocean boundary zone provides important constraints on the east-to-west variations in the total crustal extension manifested in the rifted margins of the South China Sea. The amount of new oceanic crust created by seafloor spreading plus the amount of crustal extension accommodated within the continental crust must be nearly the same for all points along the rifted margins. Because the amount of oceanic crust present is quite variable, it follows that the amount of crustal extension must be similarly variable and in a predictable way.

  13. Archaeal Diversity in Marine Sediments in the South China Sea

    NASA Astrophysics Data System (ADS)

    Wei, Y.; Wang, P.; Liu, Z.; Zhao, M.; Zhang, C.

    2010-12-01

    Archaea are widespread and play an important role in the global carbon and nitrogen cycles. However, we still have limited knowledge about archaeal diversity and their function in the natural environment. The purpose of this study was to examine the diversity, distribution and abundance of archaea associated with methane-rich sediments in the South China Sea. A gravity core (HQ08-48PC, 714 cm) was collected from the northern South China Sea and aseptically sliced into 20-cm sections. Samples from near the surface (0-20 cm), middle (350-370 cm) and bottom (630-650 cm) of the core were used for the construction of archaeal clone libraries. Chemical analysis indicated that the core was rich in methane (13.6-58.8 ppm) and had low TOC/TN ratios (< 8), which indicated a marine source of the organic matter. Total amino acids ranged between 2.72 µmol/g and 8.75 µmol/g. Phylogenetic analysis revealed that archaeal community structures were dramatically different and Crenarchaeaota dominates over Euryarchaeota among the surface, middle and bottom sediments of the core. The dominant archaeal groups were MGI (40%), MBGB (27%) and MCG (9%) in the surface sediment, MCG (35%), MBGD (20%) and MCG (20%) in the middle sediment, and MCG (52%) and MBGD (33%) in the bottom sediment. MCG and MBGD increased in phytotypes with increasing depth of the core, indicating their potential importance in deeper marine subsurface. The archaeal lipids (GDGTs) showed an increase in abundance with depth. Calculations of TEX86 based on certain types of GDGTs suggested a dramatic change in sea surface temperature (SST) that might correspond to the transition from the last glacial maximum (LGM) to post-glacial period. This study will enhance our understanding of archaeal diversity and function as well as their paleoclimate applications in the South China Sea.

  14. Modern sedimentation and extreme event in the South China Sea

    NASA Astrophysics Data System (ADS)

    Chen, Yu-Huang; Su, Chih-Chieh

    2016-04-01

    The South China Sea is the largest marginal sea of the northwest Pacific. It is situated at the plate boundary of the Eurasian, Philippine Sea, and Indian plates and also on the North Western Pacific corridor of typhoons. The unique tectonic and climatic environment makes it has to face the potential of seafloor destructions, like submarine landslides and slumps, and high sediment discharges which induced by typhoon from Philippine. In this study, we analysis the sediment properties of modern extreme event records in cores and attempt to evaluate the history of extreme events in the South China Sea. Twelve gravity cores were collected in the central South China Sea basin and around Taiping island by using R/V Ocean Research 1 from 2014 to 2015 and a series of analysis including multi-sensor core logger, XRF core scanner (Itrax), core surface images, X-radiographs, bulk density, grain size, Pb-210 chronology and X-ray diffractometer were conducted in this study. On core surface images, an obvious brownish oxidized layer exist in core top with higher Pb-210 activity beneath this oxidized layer, and we speculate this layer is caused by nature hazard. According to the sampling time, we conjecture the oxidized layer might formed by typhoon Haiyan in 2013. In addition, the Itrax data shows high manganese content only exist in this layer which might related to the modern industrial pollution delivered by typhoon induced flooding from Philippine. The sedimentation rate of the non-event years in these cores which derived from Pb-210 chronology method is about 0.02 ~0.03 cm/yr. On contrary, the event layer caused by Haiyan with a recorded maximum 87cm deposits in the South China Sea. This study aims to characterize the typhoon induced deposits in the turbidite layer and use it to identify whether the other event layers recorded in these cores were related to typhoon activities and to reconstruct the strong tropical cyclone history in the western Pacific.

  15. Effects of Litter on Seedling Emergence and Seed Persistence of Three Common Species on the Loess Plateau in Northwestern China.

    PubMed

    Zhang, Rui; Hu, Xiaowen; Baskin, Jerry M; Baskin, Carol C; Wang, Yanrong

    2017-01-01

    Litter accumulation resulting from land use change (enclosure) is one of the key variables influencing seedling recruitment and consequently the regeneration of plant populations and seed persistence in the soil seed bank. A better understanding of the effects of litter on seed germination and seedling emergence is crucial for developing a new set of indicators for grassland ecosystem health and for grassland management policy. We investigated the effects of seed position in litter and amount of litter covering the seed on seedling emergence and seed persistence of three common species on the Loess Plateau in northwestern China. Seed position beneath the litter layer provided a suitable environment for seedling emergence of the three species. A moderate amount of litter (160 g/m(2)) was beneficial for seedling emergence of the small-seeded species Stipa bungeana and Lespedeza davurica from seeds from beneath the litter layer. The large-seeded species Setaria glauca was more tolerant of a high amount of litter (240 g/m(2)) than the two small-seeded species. Seed persistence in the soil differed among the three species and also was affected by seed position in litter and amount of litter cover. The proportion of viable seeds of Stipa bungeana and Setaria glauca on top of the litter layer increased with an increase in amount of litter. Seedling emergence and seed persistence varied significantly among species, amount of litter and seed position in litter. A moderate amount of litter and seeds positioned beneath the litter layer were better for seedling recruitment than for those on top of the litter layer. A high amount of litter was more favorable for persistence of seeds positioned on top of the litter than for those beneath the litter. Our study showed that maintaining litter amount between 80 and 160 g/m(2) is optimal for S. bungeana dominated grassland on the Loess Plateau. We suggest that litter amount can serve as a guide for monitoring and managing grassland

  16. Geochemical and geomorphological evidence for the provenance of aeolian deposits in the Badain Jaran Desert, northwestern China

    NASA Astrophysics Data System (ADS)

    Hu, Fangen; Yang, Xiaoping

    2016-01-01

    Identifying provenance of aeolian deposits in the mid-latitude deserts of Asia is essential for understanding formation and changes of Earth surface processes due to palaeoclimatic fluctuations. While some earlier studies focused on the interpretation of palaeoenvironments on the basis of aeolian deposits mainly in the desert margins and inter-dune lacustrine sediments, research on provenance of desert sands in the vast Asian mid-latitude deserts is still rare. In this paper, we present new geochemical data which provide insight to the provenance of dune sands in the Badain Jaran Desert, northwestern China, an important part of this desert belt. We sampled aeolian and lacustrine sediments in various parts of the Badain Jaran Desert, and examined their major, trace and rare earth elements (REE) in bulk samples, coarse and fine fractions, respectively. In addition, we took and analyzed samples from a rarely known dune field with red sands, northeast of the Badain Jaran. Our results show that the sands from the Badain Jaran Desert are generally different from those in the red sand dune field in terms of REE pattern and geochemical characteristics, suggesting different sediment origins. Geochemical composition of the aeolian sand samples indicates these sediments should be mainly derived from mixed source rocks of granite, granitoids and granodiorite. Comparing the immobile trace elements and REE ratios of the samples from the Badain Jaran Desert, red sand dune field with rocks of granite, granitoids in their potential source areas, we conclude that: (1) The aeolian deposits in the Badain Jaran Desert are predominantly derived from the Qilian Mountains, northeastern Tibetan Plateau initially via fluvial processes; (2) The Altay Mountains and Mongolian Gobi are the ultimate source areas for the red sand dune field; (3) The Altai Mountains and Mongolian Gobi in the northwest, that could produce massive amounts of materials via intensive deflation and alluvial process

  17. Effects of Litter on Seedling Emergence and Seed Persistence of Three Common Species on the Loess Plateau in Northwestern China

    PubMed Central

    Zhang, Rui; Hu, Xiaowen; Baskin, Jerry M.; Baskin, Carol C.; Wang, Yanrong

    2017-01-01

    Litter accumulation resulting from land use change (enclosure) is one of the key variables influencing seedling recruitment and consequently the regeneration of plant populations and seed persistence in the soil seed bank. A better understanding of the effects of litter on seed germination and seedling emergence is crucial for developing a new set of indicators for grassland ecosystem health and for grassland management policy. We investigated the effects of seed position in litter and amount of litter covering the seed on seedling emergence and seed persistence of three common species on the Loess Plateau in northwestern China. Seed position beneath the litter layer provided a suitable environment for seedling emergence of the three species. A moderate amount of litter (160 g/m2) was beneficial for seedling emergence of the small-seeded species Stipa bungeana and Lespedeza davurica from seeds from beneath the litter layer. The large-seeded species Setaria glauca was more tolerant of a high amount of litter (240 g/m2) than the two small-seeded species. Seed persistence in the soil differed among the three species and also was affected by seed position in litter and amount of litter cover. The proportion of viable seeds of Stipa bungeana and Setaria glauca on top of the litter layer increased with an increase in amount of litter. Seedling emergence and seed persistence varied significantly among species, amount of litter and seed position in litter. A moderate amount of litter and seeds positioned beneath the litter layer were better for seedling recruitment than for those on top of the litter layer. A high amount of litter was more favorable for persistence of seeds positioned on top of the litter than for those beneath the litter. Our study showed that maintaining litter amount between 80 and 160 g/m2 is optimal for S. bungeana dominated grassland on the Loess Plateau. We suggest that litter amount can serve as a guide for monitoring and managing grassland

  18. High diversity of nitrogen-fixing bacteria in the upper reaches of the Heihe River, northwestern China

    NASA Astrophysics Data System (ADS)

    Tai, X. S.; Mao, W. L.; Liu, G. X.; Chen, T.; Zhang, W.; Wu, X. K.; Long, H. Z.; Zhang, B. G.; Zhang, Y.

    2013-08-01

    Vegetation plays a key role in water conservation in the southern Qilian Mountains (northwestern China), located in the upper reaches of the Heihe River. Nitrogen-fixing bacteria are crucial for the protection of the nitrogen supply for vegetation in the region. In the present study, nifH gene clone libraries were established to determine differences between the nitrogen-fixing bacterial communities of the Potentilla parvifolia shrubland and the Carex alrofusca meadow in the southern Qilian Mountains. All of the identified nitrogen-fixing bacterial clones belonged to the Proteobacteria. At the genus level, Azospirillum was only detected in the shrubland soil, while Thiocapsa, Derxia, Ectothiorhodospira, Mesorhizobium, Klebsiella, Ensifer, Methylocella and Pseudomonas were only detected in the meadow soil. The phylogenetic tree was divided into five lineages: lineages I, II and III mainly contained nifH sequences obtained from the meadow soils, while lineage IV was mainly composed of nifH sequences obtained from the shrubland soils. The Shannon-Wiener index of the nifH genes ranged from 1.5 to 2.8 and was higher in the meadow soils than in the shrubland soils. Based on these analyses of diversity and phylogeny, the plant species were hypothesised to influence N cycling by enhancing the fitness of certain nitrogen-fixing taxa. The number of nifH gene copies and colony-forming units (CFUs) of the cultured nitrogen-fixing bacteria were lower in the meadow soils than in the shrubland soils, ranging from 0.4 × 107 to 6.9 × 107 copies g-1 soil and 0.97 × 106 to 12.78 × 106 g-1 soil, respectively. Redundancy analysis (RDA) revealed that the diversity and number of the nifH gene copies were primarily correlated with aboveground biomass in the shrubland soil. In the meadow soil, nifH gene diversity was most affected by altitude, while copy number was most impacted by soil-available K. These results suggest that the nitrogen-fixing bacterial communities beneath Potentilla

  19. Lake-level Fluctuation and Climate Cyclicity Observed in Lake Strata in the Northwestern Qaidam Basin, China

    NASA Astrophysics Data System (ADS)

    Riegel, H. B.; Heermance, R. V., III; Nie, J.; Su, Q.; Garzione, C. N.

    2015-12-01

    The Pliocene and Quaternary are times of rapid, extreme climate variability, but 3-D geologic exposures of lacustrine strata from this time are rare, impeding observations of the impact of climate-change on lake sedimentation. The Qaidam Basin (QB) in western China provides a unique geologic setting, where internally drained lakes have existed for the past few million years, and recent deformation of the basin floor has uplifted and exposed lacustrine strata. This stratigraphy records a detailed history of lake level fluctuation, evaporite deposition, and climate change. We provide new paleomagnetic, δ18O and δ13C data combined with detailed sedimentology from the lower 475 m of a 900 m thick stratigraphic section (38.28N, 91.54E) in the northwestern QB to reveal a high-resolution record of sedimentation and climate change during the Plio-Quaternary. 12 magnetozones indicate an age for the lower half of the section between 6.0-3.0 Ma. The section consists of 9 lithofacies (1 mudstone, 4 sandstone, 1 conglomerate, 2 gypsum, 1 halite) that can be divided into 3 stratigraphic units based on evaporite concentration. Alternating mud, gypsum, and halite beds imply multiple lake-level fluctuations and occasional complete drying of the lake. This is consistent with >12.5‰ variation in the δ18O values of lacustrine carbonates (δ18Oc), indicating large-scale lake level fluctuation below 410 m, consistent with the boundary of Unit 1 and 2. Between 410 and 475 m, the δ18Oc values are ~-5 ‰. Above 475 m, an increase in gypsum concentration causes a thick salt-crust to develop on the outcrop, making sampling impossible. This stratigraphic level corresponds to an age of ~3.0 Ma, when the QB became hyper-arid. The presence of gypsum and halite throughout the section implies that the QB was arid and internally drained by at least 6 Ma, although the basin may have been divided into multiple lakes based on the bimodal δ18O values from different parts of the QB during that

  20. Variable mineralization processes during the formation of the Permian Hulu Ni-Cu sulfide deposit, Xinjiang, Northwestern China

    NASA Astrophysics Data System (ADS)

    Zhao, Yun; Xue, Chunji; Zhao, Xiaobo; Yang, Yongqiang; Ke, Junjun; Zu, Bo

    2016-08-01

    The Permian Hulu Ni-Cu sulfide deposit is located at the southern margin of the Central Asian Orogenic Belt (CAOB) in Northern Xinjiang, Northwestern China. The host intrusion of the Hulu deposit is composed of a layered mafic-ultramafic sequence and a dike-like unit. The layered sequence is composed of harzburgite, lherzolite, pyroxenite, gabbro, gabbrodiorite and diorite. The dike-like body comprises lherzolite and gabbro. Sulfide orebodies occur mainly within the harzburgite, pyroxenite and lherzolite at the base of the layered sequence and within the lherzolite in the dike-like body. Sulfide mineralization from the Hulu deposit shows significant depletion of PGE relative to Cu and Ni. These elements show good positive correlations with S in the sulfide mineralization from the dike-like unit but relatively weak correlations in the sulfide mineralization from the layered sequence. The sulfide mineralization from the layered unit shows excellent positive correlations between Ir and Os, Ru or Rh, and poor relationships between Ir and Pt or Pd. On the contrary, sulfide mineralization from the dike-like unit shows good correlations in the diagrams of Os, Ru, Rh, Pt and Pd against Ir. Both high Cu/Pd ratios (8855-481,398) and our modeling indicate that PGE depletion resulted from sulfide removal in a deep staging magma chamber. The evolved PGE-depleted magmas then ascended to the shallower magma chamber and became sulfide saturation due to crustal contamination. Both low Se/S ratios (33.5 × 10-6-487.5 × 10-6) and a negative correlation between Se/S and Cu/Pd ratios are consistent with the addition of crustal S. A large number of sulfide liquids segregated with minor crystallization of monosulfide solid solution (MSS) in the shallower magma chamber. When new magma pulses with unfractionated sulfide droplets entered the shallower magma chamber, the sulfide slurry containing crystallized MSS may be disrupted and mixed with the unfractionated sulfide droplets. The

  1. Orographic effects on South China Sea summer climate

    NASA Astrophysics Data System (ADS)

    Xu, Haiming; Xie, Shang-Ping; Wang, Yuqing; Zhuang, Wei; Wang, Dongxiao

    2007-09-01

    New satellite observations reveal several distinct features of the South China Sea (SCS) summer climate: an intense low-level southwesterly wind jet off the coast of south Vietnam, a precipitation band on the western flank of the north-south running Annam mountain range, and a rainfall shadow to the east in the western SCS off the east coast of Vietnam. A high-resolution full-physics regional atmospheric model is used to investigate the mechanism for the formation of SCS summer climate. A comparison of the control model simulation with a sensitivity experiment with the mountain range artificially removed demonstrates that the aforementioned features form due to orographic effects of the Annam mountains. Under the prevailing southwesterly monsoon, the mountain range forces the ascending motion on the windward and subsidence on the lee side, giving rise to bands of active and suppressed convection, respectively. On the south edge of the mountain range, the southwesterlies are accelerated to form an offshore low-level wind jet. The mid-summer cooling in the SCS induced by this wind jet further helps reduce precipitation over the central SCS. A reduced-gravity ocean model is used to investigate the ocean response to the orographically induced wind forcing, which is found to be important for the formation of the double-gyre circulation observed in the summer in SCS, in particular for the northern cyclonic circulation. Thus, orography is a key to shaping the SCS summer climate both in the atmosphere and in the ocean.

  2. Orographic effects on South China Sea summer climate

    NASA Astrophysics Data System (ADS)

    Xu, H.; Xie, S.-P.; Wang, Y.; Zhuang, W.; Wang, D.

    2008-08-01

    New satellite observations reveal several distinct features of the South China Sea (SCS) summer climate: an intense low-level southwesterly wind jet off the coast of South Vietnam, a precipitation band on the western flank of the north south running Annam mountain range, and a rainfall shadow to the east in the western SCS off the east coast of Vietnam. A high-resolution full-physics regional atmospheric model is used to investigate the mechanism for the formation of SCS summer climate. A comparison of the control model simulation with a sensitivity experiment with the mountain range artificially removed demonstrates that the aforementioned features form due to orographic effects of the Annam mountains. Under the prevailing southwesterly monsoon, the mountain range forces the ascending motion on the windward and subsidence on the lee side, giving rise to bands of active and suppressed convection, respectively. On the south edge of the mountain range, the southwesterlies are accelerated to form an offshore low-level wind jet. The mid-summer cooling in the SCS induced by this wind jet further helps reduce precipitation over the central SCS. A reduced-gravity ocean model is used to investigate the ocean response to the orographically induced wind forcing, which is found to be important for the formation of the double-gyre circulation observed in the summer in SCS, in particular for the northern cyclonic circulation. Thus, orography is a key to shaping the SCS summer climate both in the atmosphere and in the ocean.

  3. Palynological records of Holocene monsoon change from the Gulf of Tonkin (Beibuwan), northwestern South China Sea

    NASA Astrophysics Data System (ADS)

    Li, Zhen; Zhang, Yulan; Li, Yongxiang; Zhao, Jing

    2010-07-01

    Palynological records in cores C4 and B106 from the Gulf of Tonkin reveal signals of paleo-monsoon and paleoenvironmental change during the late Pleistocene and Holocene. Before ˜ 13.4 cal kyr BP, the Gulf of Tonkin was exposed to the atmosphere and covered by grassland. Starting at ˜ 11.7 cal kyr BP, the Gulf of Tonkin was inundated by brackish water, indicated by the appearance of the brackish algae Cleistosphaeridium, Sentusidinium and Spiniferites, a decrease of herb content, and an increase of Pinus. After Hainan Island was completely separated from the Leizhou Peninsula by Qiongzhou Strait at ˜ 8.5 cal kyr BP, a continuous marine sedimentary environment was found. The current patterns were similar to those of the present, with a general trend of current homogenization reflected by gradually decreasing quantities of Quercus pollen and a narrowing gap between the palynological concentrations of the southern and northern parts of the region. The data suggest that three short periods of strengthened winter monsoons and currents were centered at ˜ 6.0 cal kyr BP, ˜ 2.7 cal kyr BP and ˜ 0.2 cal kyr BP and that two short periods of strengthened summer monsoons and currents were centered at ˜ 7.5 cal kyr BP and ˜ 3.4 cal kyr BP.

  4. Latest Pleistocene and Holocene tectonic deformation along the northwestern margin of the Basin and Range province, southeastern and south-central Oregon

    SciTech Connect

    Hemphill-Haley, M.A. ); Simpson, G.A. ); Lindberg, D.N. ); Craven, G.F.; Carver, G.A.

    1993-04-01

    The northwestern margin of the Basin and Range seismotectonic province in southeastern and south-central Oregon has been characterized by historic low levels of widely dispersed seismicity, a pattern similar to the majority of the Basin and Range. Geologic mapping and limited paleoseismic investigations at locations throughout the region provide evidence for late Pleistocene and Holocene surface rupture events along several faults of two principal orientations, [approximately]N10--20[degree]E, and [approximately]N30[degree]W. Although the historical seismicity is similar to most other portions of the Basin and Range province, the pattern of late Pleistocene and Holocene faulting at the margin of the province suggests continued northward expansion of crustal extension into central Oregon. Estimated earthquake magnitudes for faults in the region, based on rupture segment length and estimated displacement are [approximately]M7. Based on Holocene recurrence estimates derived from paleoseismic sites along the Alvord segment of the Steens Mountain-Pueblo Mountain fault zone and evidence for latest Quaternary earthquakes on other faults in the region, the level of seismic hazard for the northwestern Basin and Range may be higher than was previously thought.

  5. Intensified Springtime Deep Convection over the South China Sea and the Philippine Sea Dries Southern China

    PubMed Central

    Li, Zhenning; Yang, Song; He, Bian; Hu, Chundi

    2016-01-01

    Springtime rainfall, accounting for 25–40% of the annual rainfall in southern China, exerts great agricultural and socioeconomic impacts on the region. In the recent decades, southern China has experienced a significant declining trend of precipitation in boreal spring. Meanwhile, precipitation has increased over the South China Sea and the Philippine Sea (SCS-PhS). This paper presents observational and modeling evidences suggesting that the intensified latent heating released by the convection over SCS-PhS leads to suppressed springtime rainfall over southern China. Moisture budget analysis indicates that the drying trend over southern China is due mainly to weakened convergence of moisture flux, which is controlled by a heat-induced anomalous overturning circulation reinforced by the convection over SCS-PhS. Further idealized simulations support the feature that the heat-induced overturning circulation and its corresponding anomalous cyclone can be well established in several days under the spring mean flow condition. Thus, this rapid dynamic process is associated with both the intraseasonal-to-interannual variations and the long-term change of the springtime rainfall over southern China. PMID:27461985

  6. Intensified Springtime Deep Convection over the South China Sea and the Philippine Sea Dries Southern China.

    PubMed

    Li, Zhenning; Yang, Song; He, Bian; Hu, Chundi

    2016-07-27

    Springtime rainfall, accounting for 25-40% of the annual rainfall in southern China, exerts great agricultural and socioeconomic impacts on the region. In the recent decades, southern China has experienced a significant declining trend of precipitation in boreal spring. Meanwhile, precipitation has increased over the South China Sea and the Philippine Sea (SCS-PhS). This paper presents observational and modeling evidences suggesting that the intensified latent heating released by the convection over SCS-PhS leads to suppressed springtime rainfall over southern China. Moisture budget analysis indicates that the drying trend over southern China is due mainly to weakened convergence of moisture flux, which is controlled by a heat-induced anomalous overturning circulation reinforced by the convection over SCS-PhS. Further idealized simulations support the feature that the heat-induced overturning circulation and its corresponding anomalous cyclone can be well established in several days under the spring mean flow condition. Thus, this rapid dynamic process is associated with both the intraseasonal-to-interannual variations and the long-term change of the springtime rainfall over southern China.

  7. Intensified Springtime Deep Convection over the South China Sea and the Philippine Sea Dries Southern China

    NASA Astrophysics Data System (ADS)

    Li, Zhenning; Yang, Song; He, Bian; Hu, Chundi

    2016-07-01

    Springtime rainfall, accounting for 25-40% of the annual rainfall in southern China, exerts great agricultural and socioeconomic impacts on the region. In the recent decades, southern China has experienced a significant declining trend of precipitation in boreal spring. Meanwhile, precipitation has increased over the South China Sea and the Philippine Sea (SCS-PhS). This paper presents observational and modeling evidences suggesting that the intensified latent heating released by the convection over SCS-PhS leads to suppressed springtime rainfall over southern China. Moisture budget analysis indicates that the drying trend over southern China is due mainly to weakened convergence of moisture flux, which is controlled by a heat-induced anomalous overturning circulation reinforced by the convection over SCS-PhS. Further idealized simulations support the feature that the heat-induced overturning circulation and its corresponding anomalous cyclone can be well established in several days under the spring mean flow condition. Thus, this rapid dynamic process is associated with both the intraseasonal-to-interannual variations and the long-term change of the springtime rainfall over southern China.

  8. Origin of heavy rare earth mineralization in South China

    PubMed Central

    Xu, Cheng; Kynický, Jindřich; Smith, Martin P.; Kopriva, Antonin; Brtnický, Martin; Urubek, Tomas; Yang, Yueheng; Zhao, Zheng; He, Chen; Song, Wenlei

    2017-01-01

    Heavy rare earth elements (HREE) are dominantly mined from the weathering crusts of granites in South China. Although weathering processes occur globally, no economic HREE resources of this type have yet been found outside China. Here, we report the occurrence of unidentified REE minerals in the granites from South Chinese deposits. They contain high levels of both HREE and light REE, but are strongly depleted in Ce, implying high oxidation state. These REE minerals show higher initial Nd isotope than primary REE-rich minerals (ɛNd(t)=0.9±0.8 versus −11.5±0.5). The mineralized weathering crusts inherited REE signature of the granites, but show more Ce depletion and more overall concentration of the REE. We propose, therefore, that highly oxidized, REE-rich fluids, derived from external, isotopically depleted sources, metasomatized the granites, which resulted in Ce depletion as Ce4+ and enrichment of the remaining REE, especially the HREE, contributing to formation of a globally important REE resource. PMID:28220784

  9. Antecedents of medical workplace violence in South China.

    PubMed

    Wenzhi Cai; Ling Deng; Meng Liu; Min Yu

    2011-01-01

    It has been noted that workplace violence most frequently occurs in hospitals. The purpose of this study was to explore antecedents of workplace violence in south China. The authors conducted face-to-face, in-depth, semistructured interviews with 30 hospital staff who had experienced at least one incident of workplace violence from patients during the past 12 months at three general hospitals in south China. The interviews were tape-recorded, then transcribed, and analyzed. The authors' analyses identified five major antecedents of workplace violence. First, 93.0% of medical workplace violence was related to insufficient communication between hospital staff and patients. Second, inadequate medical service quality was found to be a factor in 56.7% of the incidences. Third, unsatisfactory treatment outcome was reported in 60.0%. Fourth, heavy workload accounted for 43.3%. Fifth, patient frustration due to high medical expenses was reported in 40.0% of cases. The authors recommended a reengineering of hospital service delivery to create a more supportive and safer working environment for prevention of workplace violence.

  10. First record of Podocarpoid fossil wood in South China

    PubMed Central

    Li, Long; Jin, Jian-Hua; Quan, Cheng; Oskolski, Alexei A.

    2016-01-01

    A new species of fossil conifer wood, Podocarpoxylon donghuaiense sp. nov., is described from the late Eocene of Nadu Formation in Baise Basin of the Guangxi Province, South China. This fossil wood is characterized by distinct growth rings, circular to oval tracheids in cross section, 1–2-seriate opposite pits on radial tracheid walls, uniseriate (rarely biseriate) rays, smooth end walls of ray parenchyma cells, and the absence of resin ducts, suggesting its affinity to Podocarpaceae. The new species is distinctive from other Cenozoic woods ascribed to this family by the combination of distinctive growth rings, the absence of axial parenchyma, the occurrence of bordered pits on tangential tracheid walls, and the occurrence of 3–4 cuppressoid or taxodioid pits on cross-fields. This represents the first record of podocarpoid fossil wood in South China and provides fossil evidence for the early dispersal and diversification of Podocarpaceae in eastern Asia as well as for mild temperate seasonal climate in this region during the late Eocene. PMID:27571780

  11. Origin of heavy rare earth mineralization in South China.

    PubMed

    Xu, Cheng; Kynický, Jindřich; Smith, Martin P; Kopriva, Antonin; Brtnický, Martin; Urubek, Tomas; Yang, Yueheng; Zhao, Zheng; He, Chen; Song, Wenlei

    2017-02-21

    Heavy rare earth elements (HREE) are dominantly mined from the weathering crusts of granites in South China. Although weathering processes occur globally, no economic HREE resources of this type have yet been found outside China. Here, we report the occurrence of unidentified REE minerals in the granites from South Chinese deposits. They contain high levels of both HREE and light REE, but are strongly depleted in Ce, implying high oxidation state. These REE minerals show higher initial Nd isotope than primary REE-rich minerals (ɛNd(t)=0.9±0.8 versus -11.5±0.5). The mineralized weathering crusts inherited REE signature of the granites, but show more Ce depletion and more overall concentration of the REE. We propose, therefore, that highly oxidized, REE-rich fluids, derived from external, isotopically depleted sources, metasomatized the granites, which resulted in Ce depletion as Ce(4+) and enrichment of the remaining REE, especially the HREE, contributing to formation of a globally important REE resource.

  12. Origin of heavy rare earth mineralization in South China

    NASA Astrophysics Data System (ADS)

    Xu, Cheng; Kynický, Jindřich; Smith, Martin P.; Kopriva, Antonin; Brtnický, Martin; Urubek, Tomas; Yang, Yueheng; Zhao, Zheng; He, Chen; Song, Wenlei

    2017-02-01

    Heavy rare earth elements (HREE) are dominantly mined from the weathering crusts of granites in South China. Although weathering processes occur globally, no economic HREE resources of this type have yet been found outside China. Here, we report the occurrence of unidentified REE minerals in the granites from South Chinese deposits. They contain high levels of both HREE and light REE, but are strongly depleted in Ce, implying high oxidation state. These REE minerals show higher initial Nd isotope than primary REE-rich minerals (εNd(t)=0.9+/-0.8 versus -11.5+/-0.5). The mineralized weathering crusts inherited REE signature of the granites, but show more Ce depletion and more overall concentration of the REE. We propose, therefore, that highly oxidized, REE-rich fluids, derived from external, isotopically depleted sources, metasomatized the granites, which resulted in Ce depletion as Ce4+ and enrichment of the remaining REE, especially the HREE, contributing to formation of a globally important REE resource.

  13. The Crustal Deformation Revealed by GPS and InSAR in the Northwest Corner of the Tarim Basin, Northwestern China

    NASA Astrophysics Data System (ADS)

    Qiao, Xuejun; Yu, Pengfei; Nie, Zhaosheng; Li, Jie; Wang, Xiaoqiang; Kuzikov, Sergey I.; Wang, Qi; Yang, Shaomin

    2017-03-01

    The Northwestern Corner of the Tarim Basin (hereinafter the NOCTB) is surrounded by the Pamir salient, the south Tian Shan Mountains, and the Tarim Basin. The tectonic settings of these three structures dominate the crustal deformation patterns and seismic events in the NOCTB and its adjacent regions. We integrated the GPS and InSAR measurements to derive a large-scale three-dimensional velocity map of the NOCTB. The GPS data obtained during 38 campaigns between 1992 and 2013 were used to derive a horizontal velocity field. 149 Envisat ASAR images observed along four satellite tracks between 2003 and 2011 were processed to get a line of sight rate map based on the small baseline subset time series analysis method and a homogeneous isotropic model. Finally, we modeled the dip angle, slip rate, and locking depth of selected faults. The results indicate that the crustal convergence is not uniformly distributed across the NOCTB: more than 50% of the N-S shortening is absorbed by the Tian Shan Mountains in the southwest, whereas the N-S shortening rates are low and therefore the strain accommodations are smaller in the east of the NOCTB. The vertical displacement rates in the NOCTB range from -2 to 3 mm/year with different magnitudes in different areas. The main uplift areas are located on the junction region between frontal MPT and the southwestern STT including the Kazkeaerte fault, Aikenerte fault, the Southern Artux fault, and part areas in north of the Kalping fault. The main subsident areas are located on central belt of STT including the Totgumbaz-Alpaleh fault, Nothern Artux fault, the southwestern Karatieke fault, and the north of Puchang/Piqiang fault. Compared with the substantial N-S shortening rate of 10 mm/year, the vertical rate across each fault ranges from approximately -1 to 1 mm/year, suggesting that vertical movement in NOCTB area is relatively moderate at present. Both the horizontal and vertical rates show obvious changes across the Kazkeaerte

  14. Review of the circulation in the Beibu Gulf, South China Sea

    NASA Astrophysics Data System (ADS)

    Gao, Jingsong; Wu, Guidan; Ya, Hanzheng

    2017-04-01

    Although Beibu Gulf holds a significant geographical location and is rich in fishery resources, it has attracted only limited attention from researchers in recent decades. This study summarizes the conclusions based on the observations and model results regarding the circulation and cold water mass in the Beibu Gulf to provide a reference for further research. Affected by wind and density gradient, the spring circulation may be gulf-scale cyclonic and nested with an enclosed cyclonic gyre in the northern gulf and unclosed cyclonic gyre in the southern gulf. Meanwhile, the mechanisms of summer circulation remain controversial. Along with the results of a new numerical model, historical observations suggest that summer circulation is cyclonic and anticyclonic in the northern and southern gulfs, respectively. The northern and southern gulfs are mainly influenced by wind stress curl and South China Sea current, respectively. Similarly, although different views regarding the structure of winter circulation have been presented, a large amount of evidence supports the existence of two cyclonic gyres in the northern and southern gulfs. In addition, a southwestward current off the northwestern coast of Hainan Island is present. The circulation structure in the fall is similar to that in winter. However, the cyclonic gyre in the southern Gulf has a greater tendency to intrude northwards into the Beibu Gulf in fall than in winter, and the currents off the coast of Vietnam and the northwestern coast of Hainan Island are weaker in fall than those in winter. Most studies indicate that winter boreal circulation is driven by the monsoon wind. The most recent observations and model results suggest that the current in the Qiongzhou Strait (QS) is eastward on certain days in the boreal summer and is affected by the difference between the sea levels of the two ends of the QS and tidal rectification. Correspondingly, the volume transport is approximately -0.1 Sv (minus sign represents

  15. Composition and genesis of ferromanganese deposits from the northern South China Sea

    NASA Astrophysics Data System (ADS)

    Zhong, Yi; Chen, Zhong; González, Francisco Javier; Hein, James R.; Zheng, Xufeng; Li, Gang; Luo, Yun; Mo, Aibin; Tian, Yuhang; Wang, Shuhong

    2017-05-01

    Marine ferromanganese (Fe-Mn) nodules and crusts are archives of past environmental conditions and potential mineral resources. Over the last 30 years, many have been discovered in the northern South China Sea (SCS). To determine the origin of the Fe-Mn deposits, a comprehensive laboratory analysis of physical properties, mineralogy and geochemistry was conducted on newly collected Fe-Mn nodule/crust samples. The results revealed that there are three types of Fe-Mn deposits: (1) Fe-rich nodules containing essentially goethite occur on the northeastern slope of the SCS, with high Fe, low Mn (Mn/Fe = 0.03) and low trace metals and rare earth elements concentrations; (2) Smooth Fe-Mn nodules and crusts composed of asbolane, todorokite and CFA occur along the northwestern marginal of the SCS that have similar Fe and Mn contents (Mn/Fe = 1.21), moderate trace metal enrichments, and a positive Ce anomaly; (3) Fe-Mn nodules and crusts composed of asbolane, todorokite and birnessite that occur in the central basin of the SCS have higher Mn and lower Fe contents (Mn/Fe = 1.45). This depositional pattern was associated with major changes in oceanographic conditions and tectonic regimes. The northeastern slope deposits occur in a contourite depositional system, are strongly enriched in Fe relative to Mn (average 38.7% and 0.96%, respectively), formed from the combination of hydrogenetic and diagenetic processes. We propose a new genetic model for Fe-Mn nodules, which formed through the oxidation of pyrite and pyrite-barite concretions that formed by rapid early diagenetic growth (average 3320 mm/Myr) on continental margins above the carbonate compensation depth, and dominated by hydrocarbon seep structures and strong erosive action of bottom currents along the northeastern slope. In contrast, the introduction of vigorous deep-water flow from the North Pacific promoted the slow growth (4-7 mm/Myr) of hydrogenetic Fe-Mn nodules and crusts along the northwestern margin. Finally

  16. Nitrogen isotope chemostratigraphy across the Permian-Triassic boundary at Chaotian, Sichuan, South China

    NASA Astrophysics Data System (ADS)

    Saitoh, Masafumi; Ueno, Yuichiro; Nishizawa, Manabu; Isozaki, Yukio; Takai, Ken; Yao, Jianxin; Ji, Zhansheng

    2014-10-01

    scale in the late Permian to earliest Triassic; a systematic δ15N difference by low and high latitudes is particularly clarified. Although the enhanced nitrogen fixation throughout the Changhsingian at Chaotian was likely a regional event in northwestern South China, the composite δ15N profiles imply that the sea area in which fixed nitrogen is depleted has gradually developed worldwide in the Changhsingian, possibly acting as a prolonged stress to shallow-marine biota.

  17. Internal Wave Study in the South China Sea Using SAR

    NASA Technical Reports Server (NTRS)

    Liu, Antony K.; Hsu, Ming-Kuang; Zukor, Dorothy (Technical Monitor)

    2000-01-01

    Recently, the internal wave distribution maps in the China Seas have been compiled from hundreds of ERS-1/2, RADARSAT, and Space Shuttle SAR (Synthetic Aperture Radar) images from 1993 to 1999. Based on internal wave distribution map, most of internal waves in the northeast part of South China Sea were propagating westward. The wave crest can be as long as 200 km with amplitude of 100 m due to strong current from the Kuroshio branching out into the South China Sea. Based on the observations from drilling rigs near DongSha Island by Amoco Production Co., the solitons may be generated in a 4 km wide channel between Batan and Sabtang islands in Luzon Strait. The proposed generation mechanism is similar to the lee wave formation from a shallow topography. Both depression and elevation internal waves have been observed in the same RADARSAT ScanSAR image on May 4, 1998 near DongSha Island. Furthermore, depression and elevation internal waves have also been observed by SAR at the same location on the shelf in April and June, 1993 (in different seasons) respectively. Numerical models have been used to interpret their generation mechanism and evolution processes. Based on the SAR images, near DongSha Island, the westward propagating huge internal solitons are often encountered and diffracted/broken by the coral reefs on the shelf. After passing the island, the diffracted waves will re-merge or interact with each other. It has been observed that after the nonlinear wave-wave interaction, the phase of wave packet is shifted and wavelength is also changed. Examples of mesoscale features observed in SAR images, such as fronts, raincells, bathymetry, ship wakes, and oil spills will be presented. Recent mooring measurements in April 1999 near Dongsha Island, future field test ASIAEX (Asian Seas International Acoustics Experiment) planned for April 2001, and some pretest survey data will be discussed in this paper.

  18. Mapping structures of the South China Sea; a synthesis

    NASA Astrophysics Data System (ADS)

    Pubellier, Manuel; Savva, Dimitri; Aurelio, Mario; Yan, Qiu; Phach Phung, Van; Franke, Dieter; Rahman, Hadi A.; Mansor, Yazid M.; Auxiètre, Jean Luc; Meresse, Florian; Delescluse, Matthias; Pichot, Thibaud; Chan, Lung Sang; Le Gal, Virginie; Xin, Nie

    2015-04-01

    The South China Sea margin has been the focus of scientific interest in the past decade including ODP and IODP drilling, oil and gas exploration, and projects from several international teams onshore and offshore. The South China Sea, because of its narrow V shape oceanic crust, the wide extension of its rifted continental crust, and the various styles of rifting is an interesting playground to study the formation of passive margins. We present a synthesis of the main characteristics of the SCS on a structural map focused on the Late Mesozoic and Cenozoic features. The basement, similar in China, Vietnam and part of the western Philippines is undifferentiated. The Mesozoic location of the area was on the upper plate of a subduction zone, resulting in an impressive coverage of Cretaceous granites sometimes separated by narrow Cretaceous molasse basins. These granitic bodies, widespread offshore in the extended crust conditioned the location of the extension via large detachments and normal faults; later cut by steeper faults. The geometries of the faults vary from E-W to NE-SW indicating that the rifting underwent several stages with different stretching directions and a varying degree of extension which ultimately exhumed the mantle. Some faults are low angle detachments and therefore surround the granitic/metamorphic basement structures with an E-W general trend. Platform and reef carbonates occupy some of the bathymetric highs and developed mainly during Late Oligocene to Mid Miocene times and during Late Miocene times. The map also illustrates the coverage of the different units of the NW Borneo wedge, which actually develops offshore in the SE SCS and shifts to the NW of the Sulu Sea. Onshore Borneo, the sub-aerial conditions for the NW Borneo wedge resulted in intense erosion and deltas formation.

  19. Statistical Analysis of Acoustic Signal Propagating Through the South China Sea Basin

    DTIC Science & Technology

    2016-03-01

    ANALYSIS OF ACOUSTIC SIGNAL PROPAGATING THROUGH THE SOUTH CHINA SEA BASIN by Meihuei Chen March 2016 Thesis Advisor... ACOUSTIC SIGNAL PROPAGATING THROUGH THE SOUTH CHINA SEA BASIN 5. FUNDING NUMBERS 6. AUTHOR(S) Meihuei Chen 7. PERFORMING ORGANIZATION NAME(S) AND...China Sea (SCS) basin to study the effects of nonlinear internal waves on 400- Hz acoustic signal propagation. The acoustic arrival structure for this

  20. Correlation of surface sensible heat flux in the arid region of northwestern China with the northern boundary of the East Asian summer monsoon and Chinese summer precipitation

    NASA Astrophysics Data System (ADS)

    Wang, Hui; Li, Dongliang

    2011-10-01

    Northwestern (NW) China is the typical arid region of central Asia, and its surface sensible heat (SSH) anomaly significantly affects the Chinese climate and the atmospheric circulation of East Asia. In this study, we investigated the relationship between the SSH flux in the NW arid region of China and the northern boundary of the East Asian summer monsoon (EASM) and Chinese summer rainfall using a climatic diagnosis analysis method. Then the causes of formation were analyzed from the changes of the transfer of water vapor, geopotential height field, and the upper- and lower-level atmospheric circulation fields, and so on. It is found that during years of unusually weak (strong) SSH flux, the northern boundary of the EASM shifts northward (southward) than in normal years. There is an interplay between the SSH in the NW arid region of China and the precipitation in the northern boundary zone of the EASM: In the early stage of the monsoon, the SSH inhibits the latter precipitation, and during the peak of the monsoon, the precipitation suppresses the SSH. The teleconnection wave train structure of the geopotential height field at 500 hPa and the upper- lower-level atmospheric circulation fields above the Eurasian continent exhibit profound changes when summer SSH fluxes are unusually weak and strong. These changes are accompanied by significant alterations to the vertical velocity field and the water vapor field above northern China. The combination of these changes thereby contributes to the unusually southward shift of the northern boundary of the EASM.

  1. Pork preference for consumers in china, Japan and South Korea.

    PubMed

    Oh, S-H; See, M T

    2012-01-01

    Competition in global pork markets has increased as trade barriers have opened as a result of free trade agreements. Japanese prefer both loin and Boston butt, while Chinese prefer pork offal. Frozen pork has increased in terms of imports into China. Japanese consumers consider pork meat origin along with pork price when making purchase decisions. While the Chinese prefer a strong tasting pork product, South Korean consumers show very strong preferences to pork that is higher in fat. Therefore, South Korean consumers have a higher demand for pork belly and Boston butt. Consequently, the supply and demand of pork in Korea is hardly met, which means that importation of high fat parts is inevitable. In Korea there is lower preference toward low fat parts such as loin, picnic shoulder, and ham. During the economic depression in South Korea there have been observable changes in consumer preferences. There remains steep competition among the pork exporting countries in terms of gaining share in the international pork market. If specific consumer preferences would be considered carefully, there is the possibility to increase the amount of pork exported to these countries.

  2. Pork Preference for Consumers in China, Japan and South Korea

    PubMed Central

    Oh, S.-H.; See, M. T.

    2012-01-01

    Competition in global pork markets has increased as trade barriers have opened as a result of free trade agreements. Japanese prefer both loin and Boston butt, while Chinese prefer pork offal. Frozen pork has increased in terms of imports into China. Japanese consumers consider pork meat origin along with pork price when making purchase decisions. While the Chinese prefer a strong tasting pork product, South Korean consumers show very strong preferences to pork that is higher in fat. Therefore, South Korean consumers have a higher demand for pork belly and Boston butt. Consequently, the supply and demand of pork in Korea is hardly met, which means that importation of high fat parts is inevitable. In Korea there is lower preference toward low fat parts such as loin, picnic shoulder, and ham. During the economic depression in South Korea there have been observable changes in consumer preferences. There remains steep competition among the pork exporting countries in terms of gaining share in the international pork market. If specific consumer preferences would be considered carefully, there is the possibility to increase the amount of pork exported to these countries. PMID:25049488

  3. Nutrient pulses driven by internal solitary waves enhance heterotrophic bacterial growth in the South China Sea.

    PubMed

    Chen, Tzong-Yueh; Tai, Jen-Hua; Ko, Chia-Ying; Hsieh, Chih-Hao; Chen, Chung-Chi; Jiao, Nianzhi; Liu, Hong-Bin; Shiah, Fuh-Kwo

    2016-12-01

    This study demonstrated the potential effects of internal waves (IWs) on heterotrophic bacterial activities for the first time. Nine anchored studies were conducted from 2009-2012 in the South China Sea areas with different physical conditions, i.e. areas subjected to elevation IWs, to depression IWs, and to weak/no IWs. The latter two areas were treated as the Control sites. Field survey results indicated that within the euphotic zone, the minima of the depth-averaged bacterial production (IBP; ∼1.0 mgC m(-3) d(-1) ) and growth rate (IBμ; ∼0.1 d(-1) ) at all sites were similar. Except for one case, the maxima of IBP (6-12 mgC m(-3) d(-1) ) and IBμ (0.55-1.13 d(-1) ) of the elevation IWs areas were ∼fivefolds higher than those of the Control sites (IBP 1.7-2.1 mgC m(-3) d(-1) ; IBμ 0.13-0.24 d(-1) ). Replicate surveys conducted at the north-western area of the Dongsha atoll during spring-to-neap (NW1 survey) and neap-to-spring (NW2 survey) tide periods showed a great contrast to each other. Low variation and averages of IBμ in NW1 survey were similar to those of the Control sites, while those in NW2 were similar to the other elevation IWs sites with larger variation and higher averages of IBμ. This finding suggests that bacterial activities may be a function of the lunar fortnightly (14-day) cycle. Enrichment experiments suggested more directly that the limiting inorganic nutrients introduced by the elevation waves (EIWs) may contribute a higher IBμ within the euphotic zone.

  4. Diatom assemblages in surface sediments from the South China Sea as environmental indicators

    NASA Astrophysics Data System (ADS)

    Wu, Rui; Gao, Yahui; Fang, Qi; Chen, Changping; Lan, Binbin; Sun, Lin; Lan, Dongzhao

    2013-01-01

    We studied diatom distribution from 62 samples from the uppermost 1 cm of sediment in the South China Sea (SCS), using grabs or box corers in three cruises between 2001-2007. Fifty six genera, 256 species and their varieties were identified. Dominating species included Coscinodiscus africanus, Coscinodiscus nodulifer, Cyclotella stylorum, Hemidiscus cuneiformis, Melosira sulcata, Nitzschia marina, Roperia tesselata, Thalassionema nitzschioides, Thalassiosira excentrica, and Thalassiothrix longissima. Most surface sediments in the SCS were rich in diatoms, except for a few coarse samples. Average diatom abundance in the study area was 104 607 valve/g. In terms of the abundance, ecology, and spatial distribution, seven diatom zones (Zones 1-7) were recognized. Zone 1 (northern continental shelf) is affected by warm currents, SCS northern branch of the Kuroshio, and northern coastal currents; Zone 2 (northwestern continental shelf) is affected by intense coastal currents; Zone 3 (Xisha Islands sea area) is a bathyal environment with transitional water masses; Zone 4 (sea basin) is a bathyal-to-deep sea with stable and uniform central water masses in a semi-enclosed marginal sea; Zone 5 (Nansha Islands marine area) is a pelagic environment with relatively high surface temperature; Zone 6 (northern Sunda Shelf) is a tropical shelf environment; and Zone 7 (northern Kalimantan Island shelf area) is affected by warm waters from the Indian Ocean and coastal waters. The data indicate that these diatom zones are closely related to topography, hydrodynamics, temperature, nutrients and especially the salinity. Better understanding of the relationship between diatom distribution and the oceanographic factors would help in the reconstruction of the SCS in the past.

  5. [Field resistance of Phytophthora melonis to metalaxyl in South China].

    PubMed

    Wu, Yongguan; Lu, Shaofeng; Huang, Siliang; Fu, Gang; Chen, Liang; Xie, Dasen; Li, Qiqin; Cen, Zhenlu

    2011-08-01

    Phytophthora melonis is the casual agent of wax gourd and cucumber Phytophthora blight which becomes a constraint for sustainable production of the related crops. Metalaxyl is one of the principal fungicides for controlling the disease now. The objectives of the present study were: (1) to investigate the baseline sensitivity and field resistance of P. melonis to metalaxyl in South China; (2) to test the occurrence of metalaxyl-resistant mutants from metalaxyl-sensitive wild type strains exposed to the fungicide; and (3) to monitor the development of metalaxyl resistance in P. melonis population. Over 400 samples of wax gourd and cucumber Phytophthora blight were collected from Guangxi Zhuang Autonomous Region and Guangdong province during 2007-2010, and 193 strains of P. melonis were isolated and purified. The sensitivity of the isolated strains to metalaxyl was tested using mycelial growth rate method in vitro and floating-leaf-disk method in vivo, respectively. The metalaxyl-sensitive strains were induced on PDA plates containing 10 microg/mL metalaxyl. The sensitive, moderately resistant and resistant strains were recorded as 29.0% , 18.1% and 52.8%, respectively, among 193 tested strains. The frequency and level of resistance of P. melonis from Guangdong were higher than that from Guangxi. The strains from cucumber was generally more resistant to metalaxyl than those from wax gourd. The metalaxyl-resistant strains were frequently detected as predominant populations in most of the sampling sites and the highest resistance index (4226.9) was confirmed. Metalaxyl-resistant (M1r) mutants could be isolated from approximately 60% of the sensitive wild-type strains. The resistance level of the M mutants was 189-407 times higher than that of their sensitive parental strains. The EC50 values of 9 sensitive strains from a sampling site without a record of phenylamide fungicide application ranged from 0.0429 to 0.5461 microg/mL. Their mean EC50 value (0.3200 +/- 0

  6. A new evaporation duct climatology over the South China Sea

    NASA Astrophysics Data System (ADS)

    Shi, Yang; Yang, Kunde; Yang, Yixin; Ma, Yuanliang

    2015-10-01

    The climatology of evaporation ducts is important for shipborne electromagnetic system design and application. The evaporation duct climatology that is currently used for such applications was developed in the mid 1980s; this study presents efforts to improve it over the South China Sea (SCS) by using a state-of-the-art evaporation duct model and an improved meteorology dataset. This new climatology provides better evaporation duct height (EDH) data over the SCS, at a higher resolution of 0.312°×0.313°. A comparison between the new climatology and the old one is performed. The monthly average EDH in the new climatology is between 10 and 12 m over the SCS, higher than that in the old climatology. The spatiotemporal characteristics of the evaporation duct over the SCS in different months are analyzed in detail, based on the new climatology.

  7. Levels of endocrine disrupting compounds in South China Sea.

    PubMed

    Zhang, Li-Peng; Wang, Xin-Hong; Ya, Miao-Lei; Wu, Yu-Ling; Li, Yong-Yu; Zhang, Zu-lin

    2014-08-30

    The occurrence of estrogens in the aquatic environment has become a major concern worldwide because of their strong endocrine disrupting potency. In this study, concentrations of four estrogenic compounds, estrone (E1), 17β-estradiol (E2), 17α-ethynylestradiol (EE2), estriol (E3) were determined with liquid chromatography-tandem mass spectrometry analyses in surface water from South China Sea, and distributions and potential risks of their estrogenic activity were assessed. The estrogenic compounds E1, E2 and E3 were detected in most of the samples, with their concentrations up to 11.16, 3.71 and 21.63 ng L(-1). However, EE2 was only detected in 3 samples. Causality analysis, EEQ values from chemical analysis identified E2 as the main responsible compounds. Based on the EEQ values in the surface water, high estrogenic risks were in the coastal water, and low estrogenic risks in the open sea.

  8. Observations of Flow Variability in the Northern South China Sea

    NASA Astrophysics Data System (ADS)

    Zhu, X. H.; Zhao, R.; Guo, X.; Long, Y., Sr.

    2015-12-01

    We deployed five Pressure-recording Inverted Echo Sounders (PIES) along a satellite altimeter track across the continental slope of the northern South China Sea (NSCS) from October 2012 to July 2014, and obtained a time series of volume transport (VTPIES) across the section from their records. Applying the empirical relationship between VTPIES and the satellite altimeter sea-surface height anomaly difference across the section, we obtained a time series of volume transport (VTNSCS) over 22 years from 1992 to 2014. The VTNSCS shows a small mean value of -1.64 Sv (i.e., toward the southwest) but a significant seasonal reversal and mesoscale eddy induced fluctuations (-11.79-19.73 Sv). The monthly mean of VTNSCS over 22 years shows a maximum (3.59 Sv) in July and a minimum (-7.26 Sv) in December. This is the first long time series of volume transport for the NSCS based on in situ data.

  9. The first tunicate from the Early Cambrian of South China.

    PubMed

    Chen, Jun-Yuan; Huang, Di-Ying; Peng, Qing-Qing; Chi, Hui-Mei; Wang, Xiu-Qiang; Feng, Man

    2003-07-08

    Here we report the discovery of eight specimens of an Early Cambrian fossil tunicate Shankouclava near Kunming (South China). The tunicate identity of this organism is supported by the presence of a large and perforated branchial basket, a sac-like peri-pharyngeal atrium, an oral siphon with apparent oral tentacles at the basal end of the siphonal chamber, perhaps a dorsal atrial pore, and an elongated endostyle on the mid-ventral floor of the pharynx. As in most modern tunicates, the gut is simple and U-shaped, and is connected with posterior end of the pharynx at one end and with an atrial siphon at the other, anal end. Shankouclava differs from Cheungkongella, which was previously called a tunicate. Based on new, more complete "Cheungkongella" specimens that show branching tentacles, this form may be a lophophorate, and in any case is not a tunicate.

  10. Molecular genetic assay of mucopolysaccharidosis IVA in South China.

    PubMed

    He, Dengmin; Huang, Yonglan; Ou, Zhiying; Sheng, Huiying; Li, Sheyong; Zhao, Xiaoyuan; Li, Ru; Zheng, Jipeng; Liu, Li

    2013-12-10

    Mucopolysaccharidosis IVA (MPS IVA) is an autosomal recessive lysosomal storage disorder caused by the deficiency of N-acetylgalactosamine-6-sulfate sulfatase (GALNS). Molecular mutational analysis was performed by PCR product sequencing for fourteen exons and exon-intron boundaries of GALNS gene in 21 patients from 19 unrelated families with severe MPS IVA in South China. We identified fifteen different mutations, including 10 reported mutations (p.P125L, p.G290S, p.M318R, p.G340D, p.L366P, p.R386C, p.A392V, c.1243-1G>C, p.L440RfsX54 and p.X523E) and five novel mutations (p.N177S, p.G290R, p.F306S, p.W403_T404delinsCS, p.W520X). All five novel mutations were inherited from parents of the patients and not found in 100 normal control alleles. Three mutations, p.M318R, p.L366P and p.R386C were common, accounting for 36.8% of mutant alleles investigated. One patient homozygous of p.A392V and the other two unrelated patients homozygous of p.L366P presented classical disease course. The results show that the GALNS gene has a different mutational spectrum in South China as compared to other regions. The p.A392V and p.L366P mutations were associated with severe phenotype of MPS IVA. © 2013 Elsevier B.V. All rights reserved.

  11. Genetic types, mineralization styles, and geodynamic settings of Mesozoic tungsten deposits in South China

    NASA Astrophysics Data System (ADS)

    Zhao, Wen Winston; Zhou, Mei-Fu; Li, Yan Hei Martin; Zhao, Zheng; Gao, Jian-Feng

    2017-04-01

    South China hosts the most abundant and largest tungsten (W) deposits in the world, being a famous W metallogenic region. Located at the eastern part of the South China Block, which was formed by amalgamation of the Yangtze and Cathaysia Blocks during the Neoproterozoic, these W deposits were mainly formed during the Mesozoic. The W mineralization is dominanted by greisen, quartz-vein, skarn, and porphyry types, all of which are genetically related to the evolution of highly fractionated granitoids. Four episodes of W mineralization are recognized: (1) Late Triassic (230-210 Ma) in the central and western parts of South China; (2) Middle Jurassic (ca. 170 Ma) to Early Cretaceous (ca. 140 Ma) in the interior of South China, with the mineralization being concentrated in southern Jiangxi Province between 165 and 150 Ma; (3) Early Cretaceous (136-120 Ma) with deposits across South China; and (4) Late Cretaceous (100-80 Ma) mainly in the southwestern parts of South China. These four periods of mineralization are closely related to the closure of paleo-Tethys and subduction of the paleo-Pacific plate. In the Late Triassic, these two events caused local extensional environments, facilitating emplacement of the peraluminous granitoids, and formation of the W deposits. In the Middle Jurassic, break-off of the subducting oceanic plate resulted in emplacement of highly fractionated granites in the Nanling region. Later anticlockwise rotation of the paleo-Pacific plate created widespread S-type granitoids and associated Middle Jurassic to Early Cretaceous W mineralization in the interior of South China. Since 136 Ma, rollback of the subducting Pacific plate resulted in weak W mineralization across South China. Finally, a change of direction in the retreating plate from SE to ESE resulted in intensive mineralization of the southwestern part of South China.

  12. Pooled versus separate tree-ring δD measurements, and implications for reconstruction of the Arctic Oscillation in northwestern China.

    PubMed

    Liu, Xiaohong; An, Wenling; Treydte, Kerstin; Wang, Wenzhi; Xu, Guobao; Zeng, Xiaomin; Wu, Guoju; Wang, Bo; Zhang, Xuanwen

    2015-04-01

    Stable hydrogen isotope ratios (δD) in tree rings are an attractive but still rarely explored terrestrial archive of past climatic information. Because the preparation of the cellulose nitrate for δD measurements requires more wood and a longer preparation time than preparation techniques for other isotopes in cellulose (δ18O or δ13C), it is challenging to obtain high-resolution records, especially for slow-growing trees at high elevations and in boreal regions. Here, we tested whether annually pooled samples of Qinghai spruce (Picea crassifolia Kom.) trees from northwestern China provided results similar to those derived as the mean of individual measurements of the same trees and whether the resulting chronologies recorded useful climate information. Inter-tree variability of δD was higher than that of measured ring width for the same trees. We found higher and significant coherence between pooled and mean isotope chronologies than that among the individual series. It showed a logarithmic relationship between ring mass and δD; however, accounting for the influence of ring mass on δD values only slightly improved the strength of climatic signals in the pooled records. Tree-ring δD was significantly positively correlated with the mean, maximum, and minimum temperatures during the previous winter and with maximum temperature during the current August, and significantly negatively correlated with precipitation in the previous November to January and the current July. The winter climate signal seems to dominate tree-ring δD through the influence of large-scale atmospheric circulation patterns, i.e. the Arctic Oscillation. These results will facilitate reconstruction of winter atmospheric circulation patterns over northwestern China based on a regional tree-ring δD networks.

  13. New Ceratocystis species from Eucalyptus and Cunninghamia in South China.

    PubMed

    Liu, FeiFei; Mbenoun, Michael; Barnes, Irene; Roux, Jolanda; Wingfield, Michael J; Li, GuoQing; Li, JieQiong; Chen, ShuaiFei

    2015-06-01

    During routine surveys for possible fungal pathogens in the rapidly expanding plantations of Eucalyptus and Cunninghamia lanceolata in China, numerous isolates of unknown species in the genus Ceratocystis (Microascales) were obtained from tree wounds. In this study we identified the Ceratocystis isolates from Eucalyptus and Cunninghamia in the GuangDong, GuangXi, FuJian and HaiNan Provinces of South China based on morphology and through comparisons of DNA sequence data for the ITS, partial β-tubulin and TEF-1α gene regions. Morphological and DNA sequence comparisons revealed two previously unknown species residing in the Indo-Pacific Clade. These are described here as Ceratocystis cercfabiensis sp. nov. and Ceratocystis collisensis sp. nov. Isolates of Ceratocystis cercfabiensis showed intragenomic variation in their ITS sequences and four strains were selected for cloning of the ITS gene region. Twelve ITS haplotypes were obtained from 17 clones selected for sequencing, differing in up to seven base positions and representing two separate phylogenetic groups. This is the first evidence of multiple ITS types in isolates of Ceratocystis residing in the Indo-Pacific Clade. Caution should thus be exercised when using the ITS gene region as a barcoding marker for Ceratocystis species in this clade. This study also represents the first record of a species of Ceratocystis from Cunninghamia.

  14. Typhoon emergency response planning for the South China Sea

    SciTech Connect

    Corona, E.N.; Lynch, R.D.; Riffe, D.; Cardone, V.J.; Cox, A.; Chen, H.

    1996-12-31

    This paper describes the development, implementation and performance of a comprehensive typhoon emergency response plan (ERP) utilized during 1995 by Arco China Inc. (ACI) for their offshore Hainan Is. South China Sea development. An important component of the enhanced plan is a new system to forecast winds and sea states generated by tropical cyclones (TC) built around known uncertainties in forecasts of cyclones and well proven numerical models of the TC surface wind field and the spectral wave field. The forecast system provides specification of time histories of the winds and waves at the site for the nominally predicted track as well as the probabilities of exceedance of critical evacuation thresholds of wind speed and sea state. The ERP and forecast system were operated throughout the 1995 typhoon season and evaluated at the Yacheng development, which was seriously threatened by 15 tropical cyclones between June and November. The response to these threats in terms of interruption of operations, partial or total evacuation of offshore personnel and average downtime is described and compared to previous experience which used more conventional forecast services. The evaluation has shown the new system to provide significant benefits in terms of safety, efficiency and cost savings. The wind and sea state forecast histories provided year-round by the forecast system are also of significant benefit to the management of floating production systems.

  15. Rocky desertification treatment project in karst areas in South China

    NASA Astrophysics Data System (ADS)

    Zhou, Jinxing; Pang, Danbo; Wan, Long; Wu, Xiuqin; Wang, Genzhu

    2017-04-01

    Rocky desertification is one of the most severe ecological problems in karst areas of South China. Severe vegetation degradation, high soil erosion, high exposed bedrock and fast groundwater flow through karst conduits are typical characteristics in the rocky desertification areas. From 2008, the rocky desertification treatment project was conducted by the Chinese government to improve the local ecological environment. This paper has offered an overview of the rocky desertification treatment project, and the partitions for the rocky desertification treatment. Changes in the spatial and temporal distribution of different severity of rocky desertification were investigated. Diverse vegetation restoration modes and ecological engineering technology modes for rocky desertification management were introduced. We also discussed the vegetation restoration effects and the carbon absorbing effects by Chinese rocky desertification treatment project. Besides, the problems exist in the rocky desertification treatment were analyzed in our study. The new rocky desertification treatment project will be carried out from 2016 in China. We need continue to summarize the past experiences, and gain more achievements from the new project.

  16. The interannual oscillation of sea surface temperature in the South China Sea

    SciTech Connect

    Zhou Faxiu; Yu Shenyu; Fu Gang; Wang Dongxiao

    1994-12-31

    The South China Sea (SCS) is located in the area of the Asia monsoons and is a quasi-closed deep basin near the tropical western Pacific. The sea surface temperature anomalies (SSTA) in the South China Sea have an influence on the precipitation in flood season in the South China. The anomalies of the Asia monsoons have great effect on SST in the SCS. This paper aims at finding the features of the interannual oscillation of SST and discussing the mechanism of the SST oscillation in the SCS.

  17. Geodynamic Evolution of the Northeastern South China Sea

    NASA Astrophysics Data System (ADS)

    Yeh, Y.; Sibuet, J.; Hsu, S.; Liu, C.

    2008-12-01

    We present a geodynamic evolution model of the northeastern South China Sea (SCS) updated the kinematic context based on a re-interpretation and analysis of all available magnetic data. Using the latest available multi-channel seismic data, two significant tectonic phases T1 and T2 were identified in the northeastern SCS. T1 is a slight tensional tectonic event and T2 is a major compressive event. In the absence of the drilling data in the deep basin, the identification of the magnetic anomalies, the age of major unconformities at ODP Sites 1146 and 1148 drilled on the northeastern SCS margin as well as a re- interpretation of the tectonic subsidence curve based on drilled holes in the west Taiwan basins provided age constraints for dating these two tectonic events. Tensional phase T1 is characterized by tilted blocks and fan-shaped deposits developed shortly (8-10 Ma) after the onset of SCS oceanic domain (37.8 Ma). It corresponds to the first ENE-WSW to E-W change in spreading directions, which occurred around chron C10 (~28.7 Ma). Tectonic phase T2 is characterized by the uplift of ENE-WSW rift features and NE-SW transverse features associated with the major plate reorganization in East Asia and a northeast shift of the Ryukyu subduction zone from the Luzon-Ryukyu transform plate boundary (LRTPB) to east of the present- day position of Taiwan, which occurred 17-18 Ma ago. As the T2 intra-plate compressive deformation only occurred south of the LRTPB, we suggest that the slab pull effect of the dead slab might have been transmitted to the oceanic crust south of the already inactive LRTPB.

  18. The Changing Faces of the South China Sea

    NASA Astrophysics Data System (ADS)

    Pubellier, M. F.; Savva, D.; Franke, D.; Meresse, F.; Steuer, S.; Auxietre, J. L.; Aurelio, M.; Chamot-Rooke, N. R. A.; Chan, L. S.

    2014-12-01

    The South China Sea (SCS) region was situated during Mesozoic on the upper plate of a subduction zone. It later evolved as a collapsed continental basin on the edge of the Yenshanian Andean-type orogeny which has been since then considerably eroded, exposing only granites and relicts of Cretaceous molasse basins. The continental crust rifted from the Paleocene to the Mid Oligocene in the eastern part, and the rifting continued until the Middle Miocene in the SW, in an environment of marginal basin opened in the midst of the lower plate. Both spreading and rifting ceased when the subduction of the Proto South China Sea (PSCS) was blocked. Finally the SCS basin which was previously always open to the NE, became isolated by the docking of the northern Philippine Mobile Belt in Luzon, Mindoro and Taiwan islands, during the Late Miocene. Since then the basin subsided whereas the margins observed various amount of uplift, and subsequent gravity tectonics. We illustrate how these event are interdependent, the Cretaceous active margin opening the PSCS by rifting and oceanic crust developed from magma-poor rifting to subsequent seafloor spreading in the Paleogene. It is not clear how the inherited sub continental mantle played a role in the unusual rifting style of the SCS, whose upper crust was extremely stretched for a large time span and was sustained near sea level during the entire duration of the rifting process. The large Jurassic and Cretaceous granitic bodies conditioned the location of the extension via large detachments and normal faults; so that the present day morphology of the sea floor still reflects the location of the granites on which large reefal platforms developed. The mid Miocene cessation of subduction in the PSCS created shortening which jammed its sediments on the NE margin of Borneo, thus generating sub-aerial conditions for the NW Borneo wedge. The resulting erosion created the large deltas starting from the end of the Early Miocene. Excess of

  19. Nitrogen isotope chemostratigraphy across the Permian-Triassic boundary at Chaotian, Sichuan, South China

    NASA Astrophysics Data System (ADS)

    Saitoh, M.; Ueno, Y.; Nishizawa, M.; Isozaki, Y.; Takai, K.; Yao, J.; Ji, Z.

    2014-12-01

    Changhsingian at Chaotian was likely a regional event in northwestern South China, the composite δ15N profiles imply that the sea area in which fixed N is depleted has gradually developed worldwide in the Changhsingian, possibly acting as a prolonged stress to the shallow-marine biota.

  20. Advances in studying oceanic circulation from hydrographic data with applications in the South China Sea

    NASA Astrophysics Data System (ADS)

    Wang, Guihua; Li, Rongfeng; Yan, Changxiang

    2003-11-01

    Methods for studying oceanic circulation from hydrographic data are reviewed in the context of their applications in the South China Sea. These methods can be classified into three types according to their different dynamics as follows: (1) descriptive methods, (2) diagnostic methods without surface and bottom forcing, and (3) diagnostic methods with the above boundary forcing. The paper discusses the progress made in the above methods together with the advancement of study in the South China Sea circulation.

  1. Cruise Report: South China Sea Upper Slope Sand Dunes Project, May 8-14, 2013

    DTIC Science & Technology

    2013-06-01

    NPS-OC-14-003 NAVAL POSTGRADUATE SCHOOL MONTEREY, CALIFORNIA CRUISE REPORT: SOUTH CHINA SEA UPPER SLOPE SAND DUNES PROJECT...Report 3. DATES COVERED (From-To) May 8-14, 2013 4. TITLE AND SUBTITLE Cruise Report: South China Sea Upper Slope Sand Dunes Project, May 8-14, 2013...in partnership with Taiwan, a field project to investigate the effects of the large amplitude sand dunes , discovered on the upper slope of the

  2. Isolation, molecular characterization, and phylogenetic analysis of encephalomyocarditis virus from South China tigers in China.

    PubMed

    Liu, Huimin; Yan, Qi; Zhao, Bo; Luo, Jing; Wang, Chengmin; Du, Yingchun; Yan, Jing; He, Hongxuan

    2013-10-01

    Although encephalomyocarditis virus (EMCV) can infect many host species and cause myocarditis and sudden death in many species, little is known about EMCV infection in tigers. A virus was isolated from organs of dead South China tigers with sudden death in southern China. The production of cytopathic effect on BHK cells, and the results of PCR, electron microscopy (EM), and whole genome sequencing indicated that the pathogen was EMCV, the strain was named FJ13. Other pathogenic agents were excluded as possible pathogenic agents. Phylogenetic analyses of the whole genome, ORF (open reading frame) and CCR (capsid coding region) using the neighbour-joining method revealed that EMCV isolates cluster into two groups (group 1 and 2) with two sub-clusters within group 1 (group 1a and 1b), and FJ13 belongs to group 1a. Animal experiment showed that the isolated strain FJ13 could cause clinical symptoms and pathological changes. The results of this study indicated that FJ13 caused myocarditis of tigers and provided new epidemiologic data on EMCV in China. Copyright © 2013 Elsevier B.V. All rights reserved.

  3. An observational analysis of a derecho in South China

    NASA Astrophysics Data System (ADS)

    Xia, Rudi; Wang, Donghai; Sun, Jianhua; Wang, Gaili; Xia, Guancong

    2012-12-01

    Derechos occur frequently in Europe and the United States, but reports of derechos in China are scarce. In this paper, radar, satellite, and surface observation data are used to analyze a derecho event in South China on 17 April 2011. A derecho-producing mesoscale convective system formed in an environment with medium convective available energy, strong vertical wind shear, and a dry layer in the middle troposphere, and progressed southward in tandem with a front and a surface wind convergence line. The windstorm can be divided into two stages according to differences in the characteristics of the radar echo and the causes of the gale. One stage was a supercell stage, in which the sinking rear inflow of a high-precipitation supercell with a bow-shaped radar echo induced a Fujita F0 class gale. The other stage was a non-supercell stage (the echo was sequentially kidney-shaped, foot-shaped, and an ordinary single cell), in which downbursts induced a gale in Fujita F1 class. This derecho event had many similarities with derechos observed in western countries. For example, the windstorm was perpendicular to the mean flow, the gale was located in the bulging portion of the bow echo, and the derecho moved southward along with the surface front. Some differences were observed as well. The synoptic-scale forcing was weak in the absence of an advancing high-amplitude midlevel trough and an accompanying strong surface cyclone; however, the vertical wind shear was very strong, a characteristic typical of derechos associated with strong synoptic-scale forcing. Extremely high values of convective available potential energy and downdraft convective available potential energy have previously been considered necessary to the formation of weak-forcing archetype and hybrid derechos; however, these values were much less than 2000 J during this derecho event.

  4. On the tidally driven circulation in the South China Sea: modeling and analysis

    NASA Astrophysics Data System (ADS)

    Nelko, Varjola; Saha, Abhishek; Chua, Vivien P.

    2014-03-01

    The South China Sea is a large marginal sea surrounded by land masses and island chains, and characterized by complex bathymetry and irregular coastlines. An unstructured-grid SUNTANS model is employed to perform depth-averaged simulations of the circulation in the South China Sea. The model is tidally forced at the open ocean boundaries using the eight main tidal constituents as derived from the OSU Tidal Prediction Software. The model simulations are performed for the year 2005 using a time step of 60 s. The model reproduces the spring-neap and diurnal and semidiurnal variability in the observed data. Skill assessment of the model is performed by comparing model-predicted surface elevations with observations. For stations located in the central region of the South China Sea, the root mean squared errors (RMSE) are less than 10 % and the Pearson's correlation coefficient ( r) is as high as 0.9. The simulations show that the quality of the model prediction is dependent on the horizontal grid resolution, coastline accuracy, and boundary locations. The maximum RMSE errors and minimum correlation coefficients occur at Kaohsiung (located in northern South China Sea off Taiwan coast) and Tioman (located in southern South China Sea off Malaysia coast). This may be explained with spectral analysis of sea level residuals and winds, which reveal dynamics at Kaohsiung and Tioman are strongly influenced by the seasonal monsoon winds. Our model demonstrates the importance of tidally driven circulation in the central region of the South China Sea.

  5. Monitoring early-flood season intraseasonal oscillations and persistent heavy rainfall in South China

    NASA Astrophysics Data System (ADS)

    Gao, Jianyun; Lin, Hai; You, Lijun; Chen, Si

    2016-12-01

    Rainfall variability during the early-flood season (April-June) in South China is largely controlled by both the 10-20 and 20-70-day intraseasonal oscillations (ISO). In this study, a method is described to monitor the ISO and persistent heavy rainfall in South China. Three existing daily real-time 20-70-day ISO indices are compared. It is found that the regional East Asia-western North Pacific (EAWNP) ISO index best represents the early-flood season 20-70-day ISO in South China. A new bivariate boreal summer ISO index is designed to describe the 10-20-day ISO in the EAWNP region. Composite analysis shows that the rainfall anomaly in South China is well captured by the northward propagation of both the 10-20 and 20-70-day ISO. With different phase combinations of the 10-20 and 20-70-day EAWNP ISO, nine conditions are defined ranging from those favorable to those unfavorable to heavy rainfall in South China that can be used to effectively monitor the early-flood season ISO and persistent heavy rainfall in South China.

  6. Source, health risk and composition impact of outdoor very fine particles (VFPs) to school indoor environment in Xi'an, Northwestern China.

    PubMed

    Xu, Hongmei; Guinot, Benjamin; Cao, Junji; Li, Yaqi; Niu, Xinyi; Ho, Kin Fai; Shen, Zhenxing; Liu, Suixin; Zhang, Ting; Lei, Yali; Zhang, Qian; Sun, Jian; Gao, Jinjin

    2017-08-26

    Very fine particles (VFPs, PM0.25) are able to travel deeply into the respiratory tract and can produce adverse health effects, especially to children. Information on the VFPs in schools is generally lacking. We investigated the chemical compositions, sources and health risks of VFPs in a junior secondary school of Xi'an, China, during May 16th to 30th, 2012. The results showed that organic matter (37% and 39%), SO4(2-) (13% and 11%) and geological material (20% and 24%) were the major components of VFPs both outdoors and indoors. The VFP species indoors, such as SO4(2-) and elemental carbon, are mainly from outdoor origins, e.g. coal burning and traffic emissions. But particle resuspension by student activities, chalk dust and import from outdoors of soil dust also contributed to deteriorate air quality in the classroom. By contrast to outdoors, several indoor factors, like higher room temperature, limited volume and longer suspension time of classroom particles, can even lead to significant secondary pollutant production. Heavy metals (mainly from outside) bound to indoor VFPs are supposedly associated to non-cancer health risks, especially Pb through ingestion pathway and Mn through dermal contact. Outdoor VFPs may be associated to PAHs cancer health risks via inhalation way. This study confirms that both indoor and outdoor sources had contributions to indoor VFPs, and that VFPs health risk should be of higher concern in urban areas of Northwestern China. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Comparison of modern pollen distribution between northern and southern South China Sea

    NASA Astrophysics Data System (ADS)

    Luo, C.; Chen, M.; Xiang, R.; Liu, J.; Zhang, L.; Lu, J.

    2013-12-01

    To understand pollen transport mechanic and terrigenous area is the base to explain pollen data correctly in Southern South China Sea (Fig.1). Based on Palynology analyzing the following preliminary conclusions are listed. 1. Air pollen differences between northern and southern South China Sea 15 air pollen samples were collected from northern part of the South China Sea from August to September 2011. 13 air pollen samples were collected from southern South China Sea in December 2011. It was found that the air pollen are different between northern and southern part of South China Sea: the pollen types in the north are more abundant than in the south, Ulmaceae, Monolete spore, Cyperaceae, Euphorbiaceae, Rubiaceae, Artemisia, Chenopodiaceae, Rosaceae, Labiatae occur only in the north, they do not occur or is just sporadic in the south. The total pollen number and concentration in the north is 10 times of the south, one of the reasons may be that the sampling season in the north is autumn with more flowering plants, the sampling season in the south is winter, with fewer flowering plants; the second reason might be that pollen and spore in autumn and winter are mainly spread by the winter wind, thus they reduce from north to south. 2. Pollen differences of the surface sediments between northern and southern South China Sea 14 samples were collected from surface sediments in the northern part of the South China Sea from August to October, 2011. 12 samples were collected from surface sediments in the southern part of the South China Sea from year 1997 to 2002. The differences of pollen characteristics from the surface sediments between northern and southern part of South China Sea are: pollen types and quantities in the north are richer than in south. There are Trilete spores (35-100%), Pinus (3-65%) in northern of SCS, with pollen concentration of 33-1031grain/g. There are only a small amount of Trilete-spore and Pinus pollen in southern of SCS. Pollen concentration in

  8. 78 FR 65711 - Uncovered Innerspring Units From China, South Africa, and Vietnam Institution of Five-Year Reviews

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-01

    ... COMMISSION Uncovered Innerspring Units From China, South Africa, and Vietnam Institution of Five-Year Reviews... innerspring units from China, South Africa, and Vietnam would be likely to lead to continuation or recurrence... orders on imports of uncovered innerspring units from South Africa and Vietnam (73 FR 75390 and...

  9. Pulsed basin development on northern margin of South China Sea

    SciTech Connect

    Ru, K.; Pigott, J.D.

    1987-05-01

    Detailed analysis of the geothermal gradients, structural architecture, genetic stratigraphy, and subsidence rate history of the sedimentary basins on the northern margin of the South China Sea (NMSC) reveal three temporally distinct but regionally correlative tectonic extensional episodes. The timing of these pulsed episodes of basin development are: Episode One, Late Cretaceous to Paleocene; Episode Two, late Eocene to early Oligocene; and Episode Three, middle Miocene. Each initiating episode on the NMSC is characterized by an ephemeral (< 10 m.y.) increase in heat flow (> 3 HFU), formation of regionally en echelon grabens or half-grabens, ensuing transgression, and high subsidence rate (> 50 m/m.y.). Trends of basin boundaries and major fault trends evolved from predominantly northeast for Episode One, to northeast and east-west for Episode Two, and to northwest and east-west and for Episode Three. Tectonically, the northeast and east-west trends resulted primarily from rifting along northwest and north-south extensional directions, respectively. The orientation, sense of displacement and time of activation of the Red River fault, Vietnam fracture zone, and the northeast-east-west and northwest-east-west multiple sets of fractures may be explained as responses to episodic changes in the regional stress field utilizing the guidance of inherited zones of crustal weakness. The timing and extent of the hydrocarbon maturation, reservoir development, and stratigraphic-structural closure in the NMSC were directly affected by this pulsed tectonic activity. Therefore, exploration strategies based purely upon the NMSC being a passive rifted margin are both inappropriate and misleading.

  10. Modulation of the connection between ENSO and the South China Sea Summer Monsoon Onset by the stratospheric QBO

    NASA Astrophysics Data System (ADS)

    Jian, Maoqiu; Han, Pucheng

    2017-04-01

    The El Niño-Southern Oscillation(ENSO) can exert significant impact on the onset of South China Sea Summer Monsoon(SCSSM). We investigate the modulation effects and mechanisms of the stratospheric quasi-biennial oscillation(QBO) on the link between ENSO and the SCSSM onset. The connection between the ENSO and the SCSSM onset is shown to depend on the QBO phase. During the westerly shear phase (WS phase), the correlation between the ENSO and SCSSM onset is not significant. While in the easterly shear phase (ES phase), ENSO events can exert a significant impact on the onset dates of SCSSM with late (early) onsets of SCSSM in the El Niño (La Niña) decay years. During the ES phase, the tropical tropopause is higher over Maritime continent(MC), stratification near tropical tropopause layer(TTL) is more stable due to the temperature anomalies, and the wind shear at TTL is stronger. Therefore, the deep convection in MC is depressed and the effects of QBO strengthen and maintain the El Niño event through Walker Circulation. The effects of the WS phase is contrary. The modulation of the QBO results in the periods of El Niño events is shorter in the WS phase and cannot be sustained until the outbreak of SCSSM. Therefore, during the WS phase the link between the El Niño and the onset of SCSSM is weak. During La Niña events, the main difference in the modulations between two QBO phases on the SCSSM onset is the spatial distribution of wind anomalies. In the ES phase, the warm anomalies near 20°N, associated with the cold anomalies near equator, generate strong easterly thermal wind south of 20°N. It leads an intensification of the easterly anomalies at upper troposphere over the South China Sea(SCS), which is favorable to the early onset of SCSSM. While in the WS phase, the offsetting effect between QBO and La Niña event results in weak wind anomalies in upper troposphere over SCS. In addition, during the La Niña event years in the WS phase, cold anomalies of SST in

  11. Regional Consortia for E-Resources: A Case Study of Deals in the South China Region

    ERIC Educational Resources Information Center

    Chunrong, Luo; Jingfen, Wang; Zhinong, Zhou

    2010-01-01

    Purpose: The purpose of this paper is to analyse the current situation and the social and economic benefits from the consortia acquisitions of electronic resources by the China Academic Library and Information System (CALIS) South China Regional Centre and to recommend improvements for consortia acquisitions. Design/methodology/approach: Analyses…

  12. Assessing South China (Guangzhou) High School Students' Views on Nature of Science: A Validation Study

    ERIC Educational Resources Information Center

    Deng, Feng; Chai, Ching Sing; Tsai, Chin-Chung; Lin, Tzung-Jin

    2014-01-01

    Research on students' views on nature of science (VNOS) in Asian countries such as China is notably lacking. This study aimed to develop and validate an instrument to measure South China high school students' VNOS. Based on the previously acquired qualitative data, the instrument included seven VNOS dimensions which reflect the crucial aspects of…

  13. A Study of People-Run Tertiary Education in South and West China

    ERIC Educational Resources Information Center

    Wang, Yongyang; Secombe, Margaret

    2004-01-01

    Chinese People-Run tertiary education institutions have grown dramatically in recent years. This paper aims to discuss the government deregulation policy and its impact on private tertiary education in China since the 1980s, particularly on south and west China, Gui Zhou province. Three colleges have been selected respectively from economically…

  14. Regional Consortia for E-Resources: A Case Study of Deals in the South China Region

    ERIC Educational Resources Information Center

    Chunrong, Luo; Jingfen, Wang; Zhinong, Zhou

    2010-01-01

    Purpose: The purpose of this paper is to analyse the current situation and the social and economic benefits from the consortia acquisitions of electronic resources by the China Academic Library and Information System (CALIS) South China Regional Centre and to recommend improvements for consortia acquisitions. Design/methodology/approach: Analyses…

  15. Assessing South China (Guangzhou) High School Students' Views on Nature of Science: A Validation Study

    ERIC Educational Resources Information Center

    Deng, Feng; Chai, Ching Sing; Tsai, Chin-Chung; Lin, Tzung-Jin

    2014-01-01

    Research on students' views on nature of science (VNOS) in Asian countries such as China is notably lacking. This study aimed to develop and validate an instrument to measure South China high school students' VNOS. Based on the previously acquired qualitative data, the instrument included seven VNOS dimensions which reflect the crucial aspects of…

  16. Prevent, Promote, and Hedge: US Military Power in the South China Sea

    DTIC Science & Technology

    2012-05-22

    rising nation China intends to avoid the fate of Germany which led to WWI and that of Japan and Germany which led to WWII.41 Zoellick in his response...aligned on either side of the line would militarize the South China Sea region creating a standoff similar to the Iron Curtain formed by US and Soviet

  17. Sources and Delivery of Nutrients to the Northwestern Gulf of Mexico from Streams in the South-Central United States1

    PubMed Central

    Rebich, Richard A; Houston, Natalie A; Mize, Scott V; Pearson, Daniel K; Ging, Patricia B; Evan Hornig, C

    2011-01-01

    Abstract SPAtially Referenced Regressions On Watershed attributes (SPARROW) models were developed to estimate nutrient inputs [total nitrogen (TN) and total phosphorus (TP)] to the northwestern part of the Gulf of Mexico from streams in the South-Central United States (U.S.). This area included drainages of the Lower Mississippi, Arkansas-White-Red, and Texas-Gulf hydrologic regions. The models were standardized to reflect nutrient sources and stream conditions during 2002. Model predictions of nutrient loads (mass per time) and yields (mass per area per time) generally were greatest in streams in the eastern part of the region and along reaches near the Texas and Louisiana shoreline. The Mississippi River and Atchafalaya River watersheds, which drain nearly two-thirds of the conterminous U.S., delivered the largest nutrient loads to the Gulf of Mexico, as expected. However, the three largest delivered TN yields were from the Trinity River/Galveston Bay, Calcasieu River, and Aransas River watersheds, while the three largest delivered TP yields were from the Calcasieu River, Mermentau River, and Trinity River/Galveston Bay watersheds. Model output indicated that the three largest sources of nitrogen from the region were atmospheric deposition (42%), commercial fertilizer (20%), and livestock manure (unconfined, 17%). The three largest sources of phosphorus were commercial fertilizer (28%), urban runoff (23%), and livestock manure (confined and unconfined, 23%). PMID:22457582

  18. Physical and hygroscopic properties and CCN characteristics of the aerosols measured at an island in the northwestern tip of South Korea

    NASA Astrophysics Data System (ADS)

    Shim, S.; Kim, J.; Kim, W.; Yum, S. S.; Chang, I.

    2009-12-01

    Atmospheric aerosols have drawn great attention in recent decades for their direct and indirect effects on climate. Particularly, Asian regions of rapid industrialization are well-known for transporting enormous air pollution aerosols throughout the Pacific. As an effort to monitor the physical and hygroscopic properties of Asian continental anthropogenic aerosols, we measured total aerosol (CN) concentration, hygroscopicity and cloud condensation nuclei (CCN) concentration for about a month (August) in 2009 at a hilly site in Baekryeong Island, located at the northwestern tip of South Korea (N 37°52’, E 124°53’). Since local anthropogenic disturbance is minimal, the site is ideal for monitoring Asian continental outflow when the prevailing wind is from the west. In this study CCN characterization was also attempted. Critical supersaturation (SC) of ambient aerosols of selected diameters of 75nm and 100nm were measured with a DMA-CCN Counter setting. SC, hygroscopicity, and CCN/CN ratios are combined to estimate the CCN capability of these aerosols. Preliminarily the daily mean CN concentration varied from 2768 to 8626 cm-3 while CCN concentration at 1% supersaturation varied from 1571 to 7492 cm-3. The average of CCN/CN ratio was approximately 0.8. The 75 nm ambient particles had the SC range from 0.20 to 0.50 % whereas the 100 nm ambient particles had the SC range from 0.13 to 0.32. More detailed analysis will be shown at the conference.

  19. A reanalysis dataset of the South China Sea.

    PubMed

    Zeng, Xuezhi; Peng, Shiqiu; Li, Zhijin; Qi, Yiquan; Chen, Rongyu

    2014-01-01

    Ocean reanalysis provides a temporally continuous and spatially gridded four-dimensional estimate of the ocean state for a better understanding of the ocean dynamics and its spatial/temporal variability. Here we present a 19-year (1992-2010) high-resolution ocean reanalysis dataset of the upper ocean in the South China Sea (SCS) produced from an ocean data assimilation system. A wide variety of observations, including in-situ temperature/salinity profiles, ship-measured and satellite-derived sea surface temperatures, and sea surface height anomalies from satellite altimetry, are assimilated into the outputs of an ocean general circulation model using a multi-scale incremental three-dimensional variational data assimilation scheme, yielding a daily high-resolution reanalysis dataset of the SCS. Comparisons between the reanalysis and independent observations support the reliability of the dataset. The presented dataset provides the research community of the SCS an important data source for studying the thermodynamic processes of the ocean circulation and meso-scale features in the SCS, including their spatial and temporal variability.

  20. Nonlinear Internal Waves in the South China Sea During ASIAEX

    NASA Technical Reports Server (NTRS)

    Liu, Antony K.; Tang, David T.; Ramp, Steve R.

    2002-01-01

    Internal wave distribution maps have been compiled from more than one hundred ERS-1/2, RADARSAT and Space Shuttle SAR images in the South China Sea (SCS) from 1993 to 2000. Based on these distribution maps, most of internal waves in the northeast part of SCS were propagating westward. The wave crest can be as long as 200 km with amplitude of 100 m, due to strong current from the Kuroshio branching out into the SCS. In recent Asian Seas International Acoustics Experiment (ASIAEX), moorings have been deployed in April 2000 and May 2001. Simultaneous RADARSAT ScanSAR images have been collected during the field test to integrate with the model and the in-situ measurements in the SCS. During ASIAEX in May 2001, many large internal waves were observed at the test area and were the major features for acoustic volume interaction. The environmental parameters have been calculated based on extensive CTD castings and mooring data. Nonlinear internal wave models have been applied to simulate the wave evolution on the continental shelf and the results compare reasonably with mooring measurements. The evolution and dissipation of huge internal waves on the shelf break, mode-two waves, elevation waves, and wave-wave interaction are very important issues for acoustic propagation. The implication of internal wave effects on acoustic propagation will also be discussed.

  1. Mangrove succession enriches the sediment microbial community in South China

    PubMed Central

    Chen, Quan; Zhao, Qian; Li, Jing; Jian, Shuguang; Ren, Hai

    2016-01-01

    Sediment microorganisms help create and maintain mangrove ecosystems. Although the changes in vegetation during mangrove forest succession have been well studied, the changes in the sediment microbial community during mangrove succession are poorly understood. To investigate the changes in the sediment microbial community during succession of mangroves at Zhanjiang, South China, we used phospholipid fatty acid (PLFA) analysis and the following chronosequence from primary to climax community: unvegetated shoal; Avicennia marina community; Aegiceras corniculatum community; and Bruguiera gymnorrhiza + Rhizophora stylosa community. The PLFA concentrations of all sediment microbial groups (total microorganisms, fungi, gram-positive bacteria, gram-negative bacteria, and actinomycetes) increased significantly with each stage of mangrove succession. Microbial PLFA concentrations in the sediment were significantly lower in the wet season than in the dry season. Regression and ordination analyses indicated that the changes in the microbial community with mangrove succession were mainly associated with properties of the aboveground vegetation (mainly plant height) and the sediment (mainly sediment organic matter and total nitrogen). The changes in the sediment microbial community can probably be explained by increases in nutrients and microhabitat heterogeneity during mangrove succession. PMID:27265262

  2. Mangrove succession enriches the sediment microbial community in South China.

    PubMed

    Chen, Quan; Zhao, Qian; Li, Jing; Jian, Shuguang; Ren, Hai

    2016-06-06

    Sediment microorganisms help create and maintain mangrove ecosystems. Although the changes in vegetation during mangrove forest succession have been well studied, the changes in the sediment microbial community during mangrove succession are poorly understood. To investigate the changes in the sediment microbial community during succession of mangroves at Zhanjiang, South China, we used phospholipid fatty acid (PLFA) analysis and the following chronosequence from primary to climax community: unvegetated shoal; Avicennia marina community; Aegiceras corniculatum community; and Bruguiera gymnorrhiza + Rhizophora stylosa community. The PLFA concentrations of all sediment microbial groups (total microorganisms, fungi, gram-positive bacteria, gram-negative bacteria, and actinomycetes) increased significantly with each stage of mangrove succession. Microbial PLFA concentrations in the sediment were significantly lower in the wet season than in the dry season. Regression and ordination analyses indicated that the changes in the microbial community with mangrove succession were mainly associated with properties of the aboveground vegetation (mainly plant height) and the sediment (mainly sediment organic matter and total nitrogen). The changes in the sediment microbial community can probably be explained by increases in nutrients and microhabitat heterogeneity during mangrove succession.

  3. Nonlinear Internal Waves in the South China Sea During ASIAEX

    NASA Technical Reports Server (NTRS)

    Liu, Antony K.; Tang, David T.; Ramp, Steve R.

    2002-01-01

    Internal wave distribution maps have been compiled from more than one hundred ERS-1/2, RADARSAT and Space Shuttle SAR images in the South China Sea (SCS) from 1993 to 2000. Based on these distribution maps, most of internal waves in the northeast part of SCS were propagating westward. The wave crest can be as long as 200 km with amplitude of 100 m, due to strong current from the Kuroshio branching out into the SCS. In recent Asian Seas International Acoustics Experiment (ASIAEX), moorings have been deployed in April 2000 and May 2001. Simultaneous RADARSAT ScanSAR images have been collected during the field test to integrate with the model and the in-situ measurements in the SCS. During ASIAEX in May 2001, many large internal waves were observed at the test area and were the major features for acoustic volume interaction. The environmental parameters have been calculated based on extensive CTD castings and mooring data. Nonlinear internal wave models have been applied to simulate the wave evolution on the continental shelf and the results compare reasonably with mooring measurements. The evolution and dissipation of huge internal waves on the shelf break, mode-two waves, elevation waves, and wave-wave interaction are very important issues for acoustic propagation. The implication of internal wave effects on acoustic propagation will also be discussed.

  4. Mangrove succession enriches the sediment microbial community in South China

    NASA Astrophysics Data System (ADS)

    Chen, Quan; Zhao, Qian; Li, Jing; Jian, Shuguang; Ren, Hai

    2016-06-01

    Sediment microorganisms help create and maintain mangrove ecosystems. Although the changes in vegetation during mangrove forest succession have been well studied, the changes in the sediment microbial community during mangrove succession are poorly understood. To investigate the changes in the sediment microbial community during succession of mangroves at Zhanjiang, South China, we used phospholipid fatty acid (PLFA) analysis and the following chronosequence from primary to climax community: unvegetated shoal; Avicennia marina community; Aegiceras corniculatum community; and Bruguiera gymnorrhiza + Rhizophora stylosa community. The PLFA concentrations of all sediment microbial groups (total microorganisms, fungi, gram-positive bacteria, gram-negative bacteria, and actinomycetes) increased significantly with each stage of mangrove succession. Microbial PLFA concentrations in the sediment were significantly lower in the wet season than in the dry season. Regression and ordination analyses indicated that the changes in the microbial community with mangrove succession were mainly associated with properties of the aboveground vegetation (mainly plant height) and the sediment (mainly sediment organic matter and total nitrogen). The changes in the sediment microbial community can probably be explained by increases in nutrients and microhabitat heterogeneity during mangrove succession.

  5. Episodic rifting and subsidence in the South China sea

    SciTech Connect

    Ru, K.; Pigott, J.D.

    1986-09-01

    The South China Sea experienced at least three stages of rifting and two intervening stages of sea-floor spreading since the Early Cretaceous. Its evolution can be described by an episodic model of tectonism, one of thermal cooling and subsidence, pulsed by temporally and spatially confined heating events. Analysis of regional geologic and geophysical data suggests episodes of rifting and associated thermal activities initiated during the Late Cretaceous, the late Eocene, and the late early Miocene. The rift system corresponding to the first episode trends northeast-southwest, whereas those of the second and third trend east-west. These two trends coincide with the orientations of the major tectonic lineations within the basin. Age estimates from heat-flow and bathymetric data suggest the oceanic crust in the Southwest subbasin is considerably older (55 Ma) than that in the Northwest (35-36 Ma) or East (32 Ma) subbasins. In terms of hydrocarbon potential, the episodes of rifting and drifting would be conducive to the development of overprinted structures and the deposition of several discrete transgressive packages of source rocks and reservoirs, separated by widespread unconformities. The thermal maturity of sedimentary organic matter affected by episodic rifting and subsidence may be greater than expected on a purely passive margin of equivalent age that had not experienced repeated heating. 21 figures.

  6. Dissolved Black Carbon in the South China Sea

    NASA Astrophysics Data System (ADS)

    Fang, Z.; Yang, W.; Chen, M.; Ma, H.

    2015-12-01

    Dissolved black carbon (DBC) has been ubiquitously reported in dissolved organic matter (DOM). However, the abundance and provenance of DBC in the ocean are not well understood. Here, DBC in the South China Sea (SCS) was determined at molecular level using the benzenepolycarboxylic acids (BPCAs) method. DBC showed high concentrations in the upper 100 m seawater with the average of 1.13 μmol l-1 (n=55). In the intermediate seawater (200-1500 m), DBC ranged from 0.67 to 0.89 μmol l-1 with the average of 0.78 μmol l-1 (n=9), exhibiting nearly homogeneous distributions. The vertical distribution pattern indicated that DBC significantly degraded in the photic zone, corresponding to an attenuate constant of 12.5±4.9 km-1. The ratios of B6CA/B3CAs increased downward, implying that aromatic condensation degree of DBC increase during transport from surface to deep water. Using the standing crops of DBC in the upper 200 m and the residence time of seawater, atmospheric deposition of DBC was estimated to be 1.94 TgC yr-1, accounting for around 16% of the global BC deposition. Our study highlights that DBC could be an important component of ocean carbon cycling in Pacific Asia Marginal Seas.

  7. Regulation of South China Sea throughflow by pressure difference

    NASA Astrophysics Data System (ADS)

    Qin, Huiling; Huang, Rui Xin; Wang, Weiqiang; Xue, Huijie

    2016-06-01

    Sea Surface Height (SSH) data from the European Centre for Medium-Range Weather Forecasts-Ocean Reanalysis System 4 (ECMWF-ORAS4) are used to determine the pressure difference in connection with variability of the South China Sea ThroughFlow (SCSTF) from 1958 to 2007. Two branches of SCSTF, the Karimata-Sunda Strait ThroughFlow (KSSTF) and the Mindoro Strait ThroughFlow (MSTF), are examined. Using the ensemble empirical mode decomposition method (EEMD), time series of pressure difference and volume transport are decomposed into intrinsic mode functions and trend functions, with the corresponding variability on different time scales. Pressure difference agrees with the KSSTF volume transport on decadal time scale; while for the MSTF, pressure difference varies similarly with volume transport on interannual time scale. Separating the dynamic height difference into the thermal and haline terms, for the KSSTF more than half of the dynamic height difference (32 cm) is due to the thermal contributions; while the remaining dynamic height difference (23 cm) is due to the haline contributions. For the MSTF, the dynamic height difference (29 cm) is primarily due to the thermal contribution (26 cm).

  8. The epidemiology of tinea manuum in Nanchang area, South China.

    PubMed

    Zhan, Ping; Geng, Chengfang; Li, Zhihua; Jiang, Qing; Jin, Yun; Li, Caixia; Liu, Weida

    2013-08-01

    Tinea manuum is a common superficial fungal infection which is usually coexistent with tinea pedis; there are few studies available on the epidemiology of tinea manuum at present. This study aims to investigate the epidemiology of tinea manuum and its correlation with tinea pedis in south China. A total of 280 patients with tinea manuum were recruited. The epidemiological and clinical data were analyzed, and causative agents were isolated and identified mycologically. Totally, 84.3 % patients with tinea manuum had co-occurrence of tinea pedis, among which 88.4 % patients had experience of scratching their feet. There was a significant relationship between the touch habits and the hand infection (χ(2) = 65.451, P = 0.000). More than 90 % patients had quite the same species of isolates from multiple infected sites in one patient. Therefore, it seems that transmission of dermatophytes from the feet to hand by scratching might be a most common way. As for tinea manuum, whether "unilateral" or "bilateral" is just the result that pathogens spread from feet to hand(s), which is only a special clinical presentation of tinea.

  9. A reanalysis dataset of the South China Sea

    PubMed Central

    Zeng, Xuezhi; Peng, Shiqiu; Li, Zhijin; Qi, Yiquan; Chen, Rongyu

    2014-01-01

    Ocean reanalysis provides a temporally continuous and spatially gridded four-dimensional estimate of the ocean state for a better understanding of the ocean dynamics and its spatial/temporal variability. Here we present a 19-year (1992–2010) high-resolution ocean reanalysis dataset of the upper ocean in the South China Sea (SCS) produced from an ocean data assimilation system. A wide variety of observations, including in-situ temperature/salinity profiles, ship-measured and satellite-derived sea surface temperatures, and sea surface height anomalies from satellite altimetry, are assimilated into the outputs of an ocean general circulation model using a multi-scale incremental three-dimensional variational data assimilation scheme, yielding a daily high-resolution reanalysis dataset of the SCS. Comparisons between the reanalysis and independent observations support the reliability of the dataset. The presented dataset provides the research community of the SCS an important data source for studying the thermodynamic processes of the ocean circulation and meso-scale features in the SCS, including their spatial and temporal variability. PMID:25977803

  10. Wind-induced currents in the South China Sea

    NASA Astrophysics Data System (ADS)

    Luu, Quang-Hung; Tkalich, Pavel

    2016-04-01

    The South China Sea (SCS) is one of the Earth's largest marginal seas. Located in the transitional region between the Pacific Ocean and the Indian Ocean as well as in the convergent zone of various multi-scale atmospheric and climatic drivers, the wind-induced circulations in the SCS are highly complicated. In this study, we derive the high-resolution seasonal patterns of wind-induced circulations in the SCS using the Semi-implicit Eulerian-Lagrangian Finite-Element (SELFE) model. The complicated bathymetry is mainly resolved by the dataset of the Shuttle Radar Topography Mission (SMRT) with the resolution as fine as 15-arc second. We further improve the topography by merging it with very-fine bathymetry being digitized from satellite images for features and islands the in the middle of the SCS (the Spratly and the Paracels). The model is forced by climatological wind and atmospheric pressure from National Centers for Environmental Prediction (NCEP). High-resolution patterns of wind-induced circulations in the SCS during Northeast (NE) and Southwest (SW) monsoons are presented, zooming at small features in the middle of the SCS. We further discuss the distortions of wind-induced currents during NE and SW seasons by examining two cases: the presence and the absence of tides.

  11. Statistical analyses of sea state conditions in South China Sea

    NASA Astrophysics Data System (ADS)

    Osinowo, Adekunle; Lin, Xiaopei; Zhao, Dongliang; Wang, Zhifeng

    2017-06-01

    The statistical characterization of sea conditions in the South China Sea (SCS) was investigated by analyzing a 30-year (1976-2005) numerically simulated daily wave height and wind speed data. The monthly variation of these parameters shows that wave height and wind speed have minimum values of 0.54 m and 4.15 m s-1, respectively in May and peak values of 2.04 m and 8.12 m s-1, respectively in December. Statistical analysis of the daily wave height and wind speed and the subsequent characterization of the annual, seasonal and monthly mean sea state based on these parameters were also done. Results showed that, in general, the slight sea state prevails in the SCS and has nearly the highest occurrence in all seasons and months. The moderate sea condition prevails in the winter months of December and January while the smooth (wavelets) sea state prevails in May. Furthermore, spatial variation of sea states showed that calm and smooth sea conditions have high occurrences (25%-80%) in the southern SCS. The slight sea condition shows the largest occurrence (25%-55%) over most parts of the SCS. High occurrences (8%-17%) of the rough and very rough seas distribute over some regions in the central SCS. Sea states from high to phenomenal conditions show rare occurrence (<12%) in the northern SCS. The calm (glassy) sea condition shows no occurrence in the SCS.

  12. High dark carbon fixation in the tropical South China Sea

    NASA Astrophysics Data System (ADS)

    Zhou, Weihua; Liao, Jianzu; Guo, Yajuan; Yuan, Xiangcheng; Huang, Hui; Yuan, Tao; Liu, Sheng

    2017-08-01

    Dark carbon fixation (DCF) has been usually assumed to be insignificant in the study of microbial production and carbon cycling. In order to evaluate DCF distribution and its contribution to biogenic carbon flux, surface and vertical distribution of DCF, primary production (PP) and bacterial production (BP) were investigated in both offshore and coastal waters in the South China Sea (SCS). Surface DCF was 0.058 μg C L-1 h-1 ( 10% of PP), within the same order of magnitude as BP of 0.047 μg C L-1 h-1 in the offshore waters. Integrated over the 1500 m water column, DCF was 196 mg C m-2 h-1, corresponding to 384% of PP, and represented a newly produced source of organic matter. This suggested that DCF was an important microbial metabolic pathway in the SCS, which might support 83% carbon demand of heterotrophic prokaryotes. Interestingly, the DCF was higher in the deep water ( 0.140 μg C L-1 h-1) than the surface water ( 0.089 μg C L-1 h-1). In addition to the different microbial community, this different vertical distribution of DCF was likely due to the nutrient status, as our nutrient enrichment experiment showed that the addition of glucose, ammonium and phosphate stimulated the DCF rates, especially the addition of glucose plus ammonium.

  13. Spatial trend and pollution assessment of total mercury and methylmercury pollution in the Pearl River Delta soil, South China.

    PubMed

    Chen, Laiguo; Xu, Zhencheng; Ding, Xiaoyong; Zhang, Weidong; Huang, Yumei; Fan, Ruifang; Sun, Jiaren; Liu, Ming; Qian, Donglin; Feng, Yongbin

    2012-07-01

    Total mercury (THg) and methylmercury (MeHg) were measured in large number of soil samples collected from areas with different types of land use, different depth in the Pearl River Delta (PRD) of South China. THg and MeHg concentrations ranged from 16.7 to 3320ngg(-1) and 0.01 to 1.34ngg(-1), respectively. THg levels are highest in the top 0-20cm soil layer, and decrease from the surface to bottom layer soil. Spatial variation was observed with different types of land use. Urban parks had the highest concentrations and the other areas tended to decrease in the order of residential areas, industrial areas, vegetable fields, cereal fields, and woodlands. Temporal variation was also noted, and two relatively high THg contamination zones located in the northwestern part of the PRD have significantly expanded over the last two decades. Both THg and MeHg concentrations were correlated significantly with soil organic matter (OM), but not with soil pH. THg pollution status was evaluated using two assessment methods.

  14. Formation mechanism of the Qiongdongnan basin northwest of the South China Sea-dating the sinistral slip of the Red River Fault Zone

    NASA Astrophysics Data System (ADS)

    Sun, Z.; Jiang, J.; Xie, W.

    2010-12-01

    Locating on the northwestern margin of the South China Sea, the Qiongdongnan basin is a NE-trending rift zone in general. Bounding with the NW-trending Yinggehai basin and the Red River- East Vietnam Fault Zone to the west, the evolution of the Qiongdongnan basin bears large amounts of information about the slip of the Red River Fault zone. Combined the geological analysis with analogue modeling experiments, we suggest that the evolution of the Qiongdongnan is controlled not only by the southeastward to south southeastward extension, but also by the sinistral slip of the Red River Fault zone. The central depression of the Qiongdongnan basin is controlled mainly by the southeastward to south southeastward extension, while the southern depression developed under the combined stress filed of southeastward extension and the dextral slip along the NNW-trending Red River fault zone. The northern depression was formed by the combined effect of the sinistral slip along the Red River Fault Zone and the southeastward extension. According to the age of the shear fault starting to develop in the southwest of the Qiongdongnan basin, as well as the age for the northwestern part to develop, the sinistral slip of the Red River Fault zone began around early oligocene, later than the rifting of the Qiongdongnan basin. The sinistral slip rate of the Red River Fault zone during early Oligocene may be smaller than the displacement rate of the Qiongdongnan basin, but become reversed thereafter, which in turn caused tectonic inversion and folding along the western segment of the Qiongdongnan basin, and NW- to NNW-trending Rediel faults from late Oligocene to middle Miocene. Through the deformation history of the Qiongdongnan basin, we defined the sinistral slip stage Indochina along the Red River Fault zone from about 36Ma to 16Ma, and further a rapid slip occurring after 30Ma.

  15. Education in Rural Areas of China and South Africa: Comparative Perspectives on Policy and Educational Management. Comparative Perspectives: Education in China & South Africa.

    ERIC Educational Resources Information Center

    Gordon, Adele; Wang, Qiang

    This report on the educational systems in China and South Africa compares the policies and processes of the two countries as they attempt to expand and improve rural education. Both countries experienced a major political upheaval, and even though there is a 50-year time lag between these events, political changes ushered in radical educational…

  16. Integrating remote sensing data with WRF for improved simulations of oasis effects on local weather processes over an arid region in northwestern China

    NASA Astrophysics Data System (ADS)

    Wen, X.; Dong, W.; Liao, X.; Lu, S.; Jin, J.

    2012-12-01

    Land use/cover types derived by satellite remote sensing data from the Earth Observing System Moderate Resolution Imaging Spectroradiometer (MODIS) were used to replace the U.S. Survey (USGS) data in the Weather Research and Forecasting (WRF) model. Simulations in this study were further improved by modifying the initial fields of WRF with soil temperature and moisture observations, because these two variables are important to producing "cold-wet island" effects. These improvements enabled the WRF model to reproduce the observed "cold and wet island" effects of the oasis.; Location and landscape map of the Jinta oasis. Jinta oasis is an inverse triangle situated between 98°39‧E and 99°08‧E and 39°56‧N and 40°17‧N in the north-central Heihe River Basin in northwestern China (Fig. 1). The average annual total precipitation is about 59.5 mm and the annual potential evapotranspiration is about 2538.6 mm (Meng et al. 2009). The total area is about 1652 km2. Jinta oasis is a typical irrigated area in arid northwestern China. It has an undulating topography and varies in elevation by only 80 m. ; In the field, there were 4 automatic weather stations (AWSs) and 1 oasis meteorological tower station in the vegetated areas, and 1 Gobi meteorological tower station was located in the nonvegetated area. The four AWSs were at 2 m height, and the two tower stations were at 4 heights (1.8, 5.8, 13, and 18.9 m). This figure shows the comparison of land use/vegetation maps between the default (USGS) and modified MODIS data for the 1 km-resolution domain. Most of the oasis is irrigated cropland, with grassland decreasing rapidly in the interior and outer edges of the Jinta oasis and degrading to desert (Fig. 2b). With population growth, more and more grassland is used to plant crops, which results in the reduction of shrubland and grassland.

  17. Can the South China Sea tell us anything about Canada Basin?

    NASA Astrophysics Data System (ADS)

    Stephenson, Randell; Li, Lu

    2016-04-01

    The Canada Basin (a sub-basin within the Amerasia Basin) and the South China Sea both preserve oceanic spreading centres and adjacent passive continental margins characterised by broad continent-ocean transition zones with hyper-extended continental crust. There are indications that hyper-extension in the South China Sea occurred mainly as a result of flow within a weak lower crustal layer and that it occurred both before and after plate break-up and the onset of ocean lithosphere formation at the sea-floor spreading axis. Available geophysical data from Canada Basin permit similar inferences. Both basins are about the same size and the oceanic segment in both is about the same size. Seafloor spreading in the South China Sea took place in the Cenozoic whereas in Canada Basin it is widely believed to have occurred during the Cretaceous. Widespread magmatism expressed as the High Arctic Large Igneous Province (HALIP) may or may not have played an intrinsic, linked, role in Canada Basin formation. No similar LIP is associated with the South China Sea although one mechanism proposed to have driven its formation is ascribed to mantle plume activity in its northernmost part. More conventionally the mechanism of opening of the South China Sea is considered to be "passive" rather than "active", related to plate reconfigurations in the southeast Asia region linked or not linked to the nearby collision of India and Eurasia and/or subduction of a "proto-South China Sea". The driving mechanism for opening of Canada Basin is poorly discussed in the literature but is generally ascribed to paleo-tectonic plate reconfigurations and subduction in the northern Pacific (Eurasia-North America plates) region in the Mesozoic. Can the South China Sea tell us anything about Canada Basin in terms of the pre-existing lithosphere of each and the geodynamic processes leading to its hyper-extension and eventual break-up?

  18. Dissolved organic carbon in the South China Sea and its exchange with the Western Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Wu, Kai; Dai, Minhan; Chen, Junhui; Meng, Feifei; Li, Xiaolin; Liu, Zhiyu; Du, Chuanjun; Gan, Jianping

    2015-12-01

    Based on a large and high quality dataset of total organic carbon (TOC, an approximation of dissolved organic carbon) collected from three cruises in spring, fall and winter in 2009-2011, we examined the distribution of TOC and its seasonality in the oligotrophic regime of the Northern South China Sea (NSCS) as well as its exchanges with the West Philippine Sea (WPS) in the Northwest Pacific Ocean through the Luzon Strait, the only deep channel linking the South China Sea (SCS) and the Pacific Ocean. Surface TOC concentration in the slope and basin areas of the NSCS varied from 65 to 75 μmol L-1 with relatively high values in the northeast part (southwest of Taiwan Island) in spring, and in the eastern parts of the NSCS during fall and winter. The TOC inventory in the upper 100 m of the water column ranged from 6.0-7.5 mol m-2 with a similar distribution pattern as the surface TOC concentration. There were two most significant differences in the TOC profiles between the SCS and the WPS. One was in the upper 200 m, where more TOC was accumulated in the WPS; the other was in the intermediate layer at ~1000-1500 m, where the gradient of TOC concentration was still persistent below 1000 m in the SCS, a feature which did not exist in the WPS. At this intermediate layer, there also appeared an excess of TOC in the SCS as compared with that in the WPS. The TOC concentration below 2000 m in the SCS was identical to that in the Northwestern Pacific, both of which were ~40 μmol L-1 without significant difference among stations and seasons, suggesting that this deep water TOC was homogeneously distributed in the deep SCS basin owing to the fast replenishment of the deep water from the WPS. We adopted an isopycnal mixing model to derive the water proportion contributed respectively from the SCS and Kuroshio along individual isopycnal plane and examined the impact of the Kuroshio intrusion on the TOC in the NSCS. The upper 100 m TOC inventory in the NSCS was overall

  19. Ventilation time and anthropogenic CO2 in the South China Sea based on CFC-11 measurements

    NASA Astrophysics Data System (ADS)

    Huang, Peng; Zhang, Miming; Cai, Minggang; Ke, Hongwei; Deng, Hengxiang; Li, Wenquan

    2016-10-01

    The South China Sea (SCS) is the largest semi-enclosed marginal sea in Southeast Asia, and is bounded by the Asian continent, Philippine Archipelago, and Great Sunda Islands. Due to the wide shelves on its northwestern and southern ends as well as the presence of numerous islets, atolls and reefs, the average depth of the SCS is only 1350 m. In this study we used measurements of the transient tracer CFC-11 from the SCS to calculate ventilation time-scales and the concentration of anthropogenic CO2 (Cant) based on the transit time distribution. The CFC-11 concentrations decreased consistently with depth and the deep and bottom water in the SCS had a CFC-11 value close to the detection limit (0.01 pmol kg-1 or 0.5 ppt). The ventilation times (mean ages) for the deep and bottom water column were 500-600 years, and based on the mean age profiles the southern part of the intermediate SCS water was older than the northern part. The ventilation time distribution was in agreement with the existence of mean annual cyclonic circulation in the SCS. The mean column inventory of Cant in the northern SCS was 28.9 mol C m-2 (error range (ER): 22.8-35.6 mol C m-2), while in the southern SCS it was 28.4 mol m-2 (ER: 21.9-35.2 molCm-2). The total Cant inventory was estimated to be 1 Pg C (ER: 0.8-1.3 Pg C, referenced to the year 2011), suggesting that the SCS stores less Cant then the adjacent seas. The vertical diffusivity was estimated to be 2-4.6×10-4 m2 s-1 in the SCS based on the "transient steady state". The upwelling was estimated as 13-34 myr-1. The high diffusivity was probably due to the strong internal tide, while the strong upwelling was due to the persistent counterclockwise (cyclonic) circulation.

  20. Sedimentary records of Typhoon Haiyan in the South China Sea

    NASA Astrophysics Data System (ADS)

    Su, C. C.; Chen, Y. H.; Chang, J. H.; Hsu, H. H.; Yu, P. S.; Liu, C. S.

    2016-12-01

    South China Sea (SCS), which is located at the boundary of the Eurasian, Philippine Sea, and Indian plates, is the largest marginal sea of the northwest Pacific and also on the North Western Pacific corridor of typhoons. The unique tectonic setting and climatic conditions make it has to face the severe natural hazards, like submarine landslides, and high sediment discharges which induced by typhoon. On November 8, 2013, the Typhoon Haiyan, which was one of the largest tropical cyclones ever recorded in western Pacific, devastated Philippines and caused catastrophic destruction. Before the Typhoon Haiyan reached Hainan Province, China and Quangninh Province, Vietnam, it emerged over the SCS. How was the large amount of terrestrial materials distributed and recorded in deep sea sediments by such intense typhoon? Is it possible for us to reconstruct the history of extreme tropical cyclones by using deep sea cores? In this study, twelve gravity cores were collected in the Central SCS Basin and around Taiping Island (Itu Aba Island) from 2014 to 2015 and a series of analysis including Multi-Sensor Core Logger, XRF Core Scanner, core surface and X-radiograph images, grain size, and excess 210Pb chronology were conducted for modern extreme event records in cores and attempt to evaluate the possibility of reconstructed extreme typhoon records in cores from the SCS. On core surface images, an obvious brownish oxidized layer exist in core top with higher 210Pb activities beneath the layer. According to the sampling time, we conjecture the oxidized layer might formed by Typhoon Haiyan in 2013. In addition, the Itrax data shows high manganese content only exist in this layer which might related to the modern industrial pollution delivered by typhoon induced flooding from Philippines. The Power Barge 103 of Napocor in Estancia IIoilo was dislodged from its mount by Typhoon Haiyan and the United Nations Disaster Assessment and Coordination Team reported 600,000 liters of bunker

  1. Nature, diversity of deposit types and metallogenic relations of South China

    USGS Publications Warehouse

    Zaw, K.; Peters, S.G.; Cromie, P.; Burrett, C.; Hou, Z.

    2007-01-01

    The South China Region is rich in mineral resources and has a wide diversity of deposit types. The region has undergone multiple tectonic and magmatic events and related metallogenic processes throughout the earth history. These tectonic and metallogenic processes were responsible for the formation of the diverse styles of base and precious metal deposits in South China making it one of the resource-rich regions in the world. During the Proterozoic, the South China Craton was characterised by rifting of continental margin before eruption of submarine volcanics and development of platform carbonate rocks, and the formation of VHMS, stratabound copper and MVT deposits. The Phanerozoic metallogeny of South China was related to opening and closing of the Tethyan Ocean involving multiple orogenies by subduction, back-arc rifting, arc-continent collision and post-collisional extension during the Indosinian (Triassic), Yanshanian (Jurassic to Cretaceous) and Himalayan (Tertiary) Orogenies. The Late Palaeozoic was a productive metallogenic period for South China resulting from break-up and rifting of Gondwana. Significant stratabound base and precious metal deposits were formed during the Devonian and Carboniferous (e.g., Fankou and Dabaoshan deposits). These Late Palaeozoic SEDEX-style deposits have been often overprinted by skarn systems associated with Yanshanian magmatism (e.g., Chengmenshan, Dongguashan and Qixiashan). A number of Late Palaeozoic to Early Mesozoic VHMS deposits also developed in the Sanjiang fold belt in the western part of South China (e.g., Laochang and Gacun). South China has significant sedimentary rock-hosted Carlin-like deposits, which occur in the Devonian- to Triassic-aged accretionary wedge or rift basins at the margin of the South China Craton. They are present in a region at the junction of Yunnan, Guizhou, and Guangxi Provinces called the 'Southern Golden Triangle', and are also present in NW Sichuan, Gansu and Shaanxi, in an area known as

  2. Early Cambrian Pentamerous Cubozoan Embryos from South China

    PubMed Central

    Han, Jian; Kubota, Shin; Li, Guoxiang; Yao, Xiaoyong; Yang, Xiaoguang; Shu, Degan; Li, Yong; Kinoshita, Shunichi; Sasaki, Osamu; Komiya, Tsuyoshi; Yan, Gang

    2013-01-01

    Background Extant cubozoans are voracious predators characterized by their square shape, four evenly spaced outstretched tentacles and well-developed eyes. A few cubozoan fossils are known from the Middle Cambrian Marjum Formation of Utah and the well-known Carboniferous Mazon Creek Formation of Illinois. Undisputed cubozoan fossils were previously unknown from the early Cambrian; by that time probably all representatives of the living marine phyla, especially those of basal animals, should have evolved. Methods Microscopic fossils were recovered from a phosphatic limestone in the Lower Cambrian Kuanchuanpu Formation of South China using traditional acetic-acid maceration. Seven of the pre-hatched pentamerous cubozoan embryos, each of which bears five pairs of subumbrellar tentacle buds, were analyzed in detail through computed microtomography (Micro-CT) and scanning electron microscopy (SEM) without coating. Results The figured microscopic fossils are unequivocal pre-hatching embryos based on their spherical fertilization envelope and the enclosed soft-tissue that has preserved key anatomical features arranged in perfect pentaradial symmetry, allowing detailed comparison with modern cnidarians, especially medusozoans. A combination of features, such as the claustrum, gonad-lamella, suspensorium and velarium suspended by the frenula, occur exclusively in the gastrovascular system of extant cubozoans, indicating a cubozoan affinity for these fossils. Additionally, the interior anatomy of these embryonic cubozoan fossils unprecedentedly exhibits the development of many new septum-derived lamellae and well-partitioned gastric pockets unknown in living cubozoans, implying that ancestral cubozoans had already evolved highly specialized structures displaying unexpected complexity at the dawn of the Cambrian. The well-developed endodermic lamellae and gastric pockets developed in the late embryonic stages of these cubozoan fossils are comparable with extant pelagic

  3. Characterizing the Phytoplankton Community of the South China Sea

    NASA Astrophysics Data System (ADS)

    Aleman, M.; Subramaniam, A.; Hay, I.

    2016-12-01

    The South China Sea (SCS) is a semi-enclosed tropical basin that receives nutrients from two main sources: coastal upwelling and river runoff from the surrounding countries. The southwest (SW) summer monsoon that occurs between March and September drives upwelling off the coast of Vietnam, a rarity compared to most upwelling systems that are driven by eastern boundary current systems. The upwelling in the SCS and the intensity of the SW monsoon are sensitive to climate variability and are affected by phenomenon such as El Niño Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD). The size and location of the Mekong River plume also varies from year to year due to the variation in rainfall and wind strength of the monsoon. The riverine input is also influenced by anthropogenic activity such as agriculture, damming, and land-use changes. Different nutrients are supplied from these two main sources and in different quantities, and affect the structure of the phytoplankton community. Phytoplankton comprise the base of the food web, supporting the growth of higher organisms and ultimately support fisheries. We need to understand how the supply of different nutrients alters the phytoplankton community of the SCS. We sampled 22 stations along the coast of Vietnam aboard the R/V Falkor of the Schmidt Ocean Institute during the pre-monsoon season. High performance liquid chromatography (HPLC) and flow cytometric techniques will be used to characterize the phytoplankton community. The relationship between the different water masses, nutrient sources, and phytoplankton community found in the SCS will be presented.

  4. Cenozoic evolution of Xisha carbonate platforms, Northern South China Sea

    NASA Astrophysics Data System (ADS)

    Wu, S.; Ma, Y.; Dong, D.

    2009-12-01

    During the Tertiary, extensive tropical shallow-water carbonates, including reefs, were deposited in the tectonically complex region of the South China Sea (SCS) and adjacent areas. Previous studies show that large quantity reefs and carbonate sediments developed in the Xisha Islands, but no further study, especially the distribution and development model, was blank because lack of enough data. Based on the fine interpretation of seismic data of carbonate platform and different types of reefs in the Xisha Islands, we proposed that the evolution process of the carbonate platform and reef in the Xisha Islands can be divided into four stages: 1. Isolated carbonate platform of initial stage in Early Miocene; 2. Carbonate platforms widely developed in the Middle Miocene and seaward prograding sequence formed; 3. With the rising sea level, some low-lying area was floodied in Late Miocene and the carbonate platforms and reefs in these areas were drowned to death, the carbonate platform in the Xisha Islands became fade; 4. Sea level continued rising and most area of the Xisha Islands was flooded but the carbonate platforms and reefs can develop at high points. Various factors have influenced the development of the Xisha carbonate platform. The two main factors in this regard are basement structure and relative sea-level change. Based on the development and distribution of various facies belts, we now consider the influence of these two factors on the development of the Xisha carbonate platform. One is the Tectonic movements and the other is Eustatic Fluctuation of sea level control on development of carbonate platforms in the Xisha Islands.

  5. Geography of Food Consumption Patterns between South and North China.

    PubMed

    Song, Fangfang; Cho, Mi Sook

    2017-05-05

    The geographical environment, food culture, and dietary habits are substantially different between the southern and northern regions in China. We investigated the associations with dietary patterns and metabolic syndrome between Chinese adult from the southern and northern regions (North: 1249; South: 1849) using data from the Chinese Health and Nutrition 2009 survey. Respectively, four dietary patterns were identified by factor analysis in each of the two regions. Using factor analysis, each dietary pattern of factor score was calculated for three groups by tertile (T1 < T2 < T3). In the northern region, the association between the Alcohol and Western pattern and the risk of abdominal obesity (OR: 1.31; 95%: 1.01, 1.68) (OR: Odds Ratio), hypertriglyceridemia (OR: 1.35; 95%: 1.05, 1.74), high fasting blood glucose (OR: 1.37; 95%: 1.05, 1.80), and hypertension (OR: 1.55; 95%: 1.45, 1.99) was increased compared T1 to T3. In the southern region, the Convenience Food pattern was positively associated with hypertriglyceridemia (OR: 1.53; 95%: 1.03, 2.26), low high density lipoprotein (HDL)-cholesterol (OR: 1.96; 95%: 1.12, 3.43), and metabolic syndrome (OR: 1.79; 95%: 1.03, 3.11). The Alcohol dietary pattern was positively associated with high fasting blood glucose (OR: 1.83, 95%: 1.13, 2.97). There are some dietary pattern differences in the two regions. It is necessary to consider the factors of food culture and food intake habits in order to provide nutrition education to Chinese individuals from different regions in the future.

  6. Circulation and oxygenation of the glacial South China Sea

    NASA Astrophysics Data System (ADS)

    Li, Dawei; Chiang, Tzu-Ling; Kao, Shuh-Ji; Hsin, Yi-Chia; Zheng, Li-Wei; Yang, Jin-Yu Terence; Hsu, Shih-Chieh; Wu, Chau-Ron; Dai, Minhan

    2017-05-01

    Degree of oxygenation in intermediate water modulates the downward transferring efficiency of primary productivity (PP) from surface water to deep water for carbon sequestration, consequently, the storage of nutrients versus the delivery and sedimentary burial fluxes of organic matter and associated biomarkers. To better decipher the PP history of the South China Sea (SCS), appreciation about the glacial-interglacial variation of the Luzon Strait (LS) throughflow, which determines the mean residence time and oxygenation of water mass in the SCS interior, is required. Based on a well-established physical model, we conducted a 3-D modeling exercise to quantify the effects of sea level drop and monsoon wind intensity on glacial circulation pattern, thus, to evaluate effects of productivity and circulation-induced oxygenation on the burial of organic matter. Under modern climatology wind conditions, a 135 m sea-level drop results in a greater basin closeness and a ∼24% of reduction in the LS intermediate westward throughflow, consequently, an increase in the mean water residence time (from 19.0 to 23.0 years). However, when the wind intensity was doubled during glacial low sea-level conditon, the throughflow restored largely to reach a similar residence time (18.4 years) as today regardless its closeness. Comparing with present day SCS, surface circulation pattern in glacial model exhibits (1) stronger upwelling at the west off Luzon Island, and (2) an intensified southwestward jet current along the western boundary of the SCS basin. Superimposed hypothetically by stronger monsoon wind, the glacial SCS conditions facilitate greater primary productivity in the northern part. Manganese, a redox sensitive indicator, in IMAGES core MD972142 at southeastern SCS revealed a relatively reducing environment in glacial periods. Considering the similarity in the mean water residence time between modern and glacial cases, the reducing environment of the glacial southeastern SCS

  7. Riverine carbon fluxes to the South China Sea

    NASA Astrophysics Data System (ADS)

    Huang, T. H.; Chen, C. T. A.; Tseng, H. C.; Lou, J. Y.; Wang, S. L.; Yang, L.; Kandasamy, S.; Gao, X.; Wang, J. T.; Aldrian, E.; Jacinto, G. S.; Anshari, G. Z.; Sompongchaiyakul, P.; Wang, B. J.

    2017-05-01

    The high precipitation around Southeast Asia results in abundant freshwater outflow, which transports terrestrial dissolved and particulate material to the world's largest marginal sea, namely, the South China Sea (SCS). To estimate the riverine carbon flux to the SCS, carbonate data from 42 rivers were collected. These results, combined with literature data for 13 rivers, indicate that the concentrations of dissolved inorganic carbon (DIC) are positively correlated with the cation exchange capacity and the bulk density, except for the Low Discharge category. The highest DIC concentration and flux are in the Low and Medium Discharge categories. Negative correlations exist between dissolved organic carbon (DOC) concentrations and the base saturation in the Low and High Discharge categories and between DOC and bulk density in the Low and Medium Discharge categories. However, the correlation between the DOC concentration and the organic carbon content in the soil is only significant in the Medium Discharge category. Once the negative exponential relationships between the particulate inorganic carbon (PIC) or the particulate organic carbon (POC) and the total suspended matter are determined, these can be used to estimate the PIC and POC carbon fluxes. Of the annual riverine carbon flux, 83.0 ± 8.1 Tg C, 40.14 ± 6.11 Tg is DIC, 25.03 ± 4.54 Tg is DOC, 1.83 ± 0.35 Tg is PIC, and 16.03 ± 2.87 Tg is POC. The total discharge amounts to 6.2-10.3% of the global riverine discharge for a sea covering only 1% of the world's ocean surface area and for watersheds covering only 2.2% of the global land mass.

  8. Observations of SST diurnal variability in the South China Sea

    NASA Astrophysics Data System (ADS)

    Tu, Qianguang; Pan, Delu; Hao, Zengzhou; Chen, Jianyu

    2015-10-01

    In this study, a 3-hourly time resolution gap free sea surface temperature (SST) analysis is generated to resolve the diurnal cycle in the South China Sea (SCS, 0°-25°N, 100°-125°E).It takes advantage of hourly geostationary satellite MTSAT observations and combines three infrared and two microwave polar satellite observations at different local times. First, all the data are classified into eight SST datasets at 3 hour intervals and then remapped to 0.05°resolution grids. A series of critical quality control is done to remove the outliers.Then bias adjustment is applied to the polar satellite observations with reference to the MTSAT data. Finally, the six satellites SST data are blended by using the optimal interpolated algorithm. The 3-hourly blended SST is compared against buoy measurements. It shows a good agreement that the biases do not exceed 0.2 °C and root mean square errors range from 0.5 to 0.65 °C. A typical diurnal cycle similar to sine wave is observed. The minimum SST occurs at around 0600h and warming peak occurring between 1300h and 1500h local solar time and then decrease in the late afternoon, tapering off at night on March 13, 2008 for example. The frequency of diurnal warming events derived from four years of the blended SST provides solid statistics to investigate the seasonal and spatial distributions of the diurnal warming in the SCS. The sea surface diurnal warming tends to appear more easily in spring, especially in the coastal regions than other seasons and the central regions.

  9. Crustal density structure in northwestern South America derived from analysis and 3-D modeling of gravity and seismicity data

    NASA Astrophysics Data System (ADS)

    Sanchez-Rojas, J.; Palma, M.

    2014-11-01

    This paper presents a three-dimensional (3-D) interpretation of new gravity and seismicity datasets for northern South America. A 3-D forward density model was constructed on the basis of deep wide-angle seismic refraction sections, Moho depth from receiver functions, and surface geology. Density values were estimated from published borehole data for sediments by using empirical velocity-density functions and considering mineralogical-chemical composition variations under typical pressure-temperature conditions for upper and lower crustal rocks. The modeled 3-D density structure was kept as simple as possible. The continental and oceanic plates were formed by two sedimentary bodies, one crustal body, and one mantle lithosphere body overlying a sub-lithospheric mantle. The Caribbean plate was modeled with an atypical crustal thickness of ~ 18 km (including sediments). The geometry of the Caribbean plate was modeled using a combination of gravity modeling and analyses of the seismicity and focal-mechanism solutions. Intermediate seismicity and the orientation of the T-axes appeared aligned along the predicted position of the slab. As a result, the estimated slab dip angle under Maracaibo and the Mérida Andes was ~ 15° and increases up to ~ 20° after 100 km depth. The model shows two orientations in the slab strike: ~ N150°E ± 5 in western Colombia and southward underneath the Maracaibo block. The modeling results suggest that the northern South American upper and lower crusts are relatively light and the density of the Caribbean crust is typical for an oceanic crust.

  10. Atmospheric short-chain chlorinated paraffins in China, Japan, and South Korea.

    PubMed

    Li, Qilu; Li, Jun; Wang, Yan; Xu, Yue; Pan, Xiaohui; Zhang, Gan; Luo, Chunling; Kobara, Yuso; Nam, Jae-Jak; Jones, Kevin C

    2012-11-06

    This study presents the first investigation of concentrations and congener group patterns of atmospheric short-chain chlorinated paraffins (SCCPs) throughout East Asia. Based on an absorption rate calibration experiment, a spatial survey of SCCPs was performed using passive air samplers in China, Japan, and South Korea during two separate periods in 2008. The atmospheric concentrations of SCCPs in China were clearly greater than those in Japan and South Korea, both of which exceed the levels determined for other regions of the world. C(10) components were the most abundant type of SCCPs in China, whereas C(11) components were dominant in Japan and South Korea. With respect to the total chlorine content, Cl(6) and Cl(5) were the predominant compounds in China and Japan; however, Cl(6) and Cl(7) were predominant in South Korea. A similar pattern was also found for remote sites within China, Japan, and South Korea, respectively. Together with the back-trajectories calculated for the remote sites, the results indicate that the SCCPs in the air of East Asia were mainly influenced by local sources due to their relatively low long-range atmospheric transport potential compared to other POPs.

  11. Modeling Study of the Effect of Anthropogenic Aerosols on Late Spring Drought in South China

    SciTech Connect

    Hu, Ning; Liu, Xiaohong

    2013-10-01

    In this study, the mechanisms underlying the decadal variability of late spring precipitation in south China are investigated using the latest version 1 of Community Earth System Model (CESM1). We aim to unravel the effects of different climate forcing agents, such as aerosols and greenhouse gases (GHGs), on the decadal variation of precipitation with transient experiments from pre-industry (for year 1850) to present-day (for year 2000). Our results reveal that: (1) CESM1 can reproduce the climatological features of atmospheric circulation and precipitation for the late spring in south China; (2) Only simulations including the forcing of anthropogenic aerosols can reproduce the observed decreasing trend of late spring precipitation from 1950-2000 in south China; (3) Aerosols affect the decadal change of precipitation mainly by altering the large scale atmospheric circulation, and to a less extent by increasing the lower-tropospheric stability to inhibit the convective precipitation; and (4) In comparison, other climate forcing agents, such as GHGs, have much smaller effects on the decadal change of spring precipitation in south China. Key words: precipitation, aerosols, climate change, south China, Community Earth System Model

  12. Combination of magnetic parameters and heavy metals to discriminate soil-contamination sources in Yinchuan--a typical oasis city of Northwestern China.

    PubMed

    Xia, Dunsheng; Wang, Bo; Yu, Ye; Jia, Jia; Nie, Yan; Wang, Xin; Xu, Shujing

    2014-07-01

    Various industrial processes and vehicular traffic result in harmful emissions containing both magnetic minerals and heavy metals. In this study, we investigated the levels of magnetic and heavy metal contamination of topsoils from Yinchuan city in northwestern China. The results demonstrate that magnetic mineral assemblages in the topsoil are dominated by pseudo-single domain (PSD) and multi-domain (MD) magnetite. The concentrations of anthropogenic heavy metals (Cr, Cu, Pb and Zn) and the magnetic properties of χlf, SIRM, χARM, and 'SOFT' and 'HARD' remanence are significantly correlated, suggesting that the magnetic minerals and heavy metals have common sources. Combined use of principal components and fuzzy cluster analysis of the magnetic and chemical data set indicates that the magnetic and geochemical properties of the particulates emitted from different sources vary significantly. Samples from university campus and residential areas are mainly affected by crustal material, with low concentrations of magnetic minerals and heavy metals, while industrial pollution sources are characterized by high concentrations of coarse magnetite and Cr, Cu, Pb and Zn. Traffic pollution is characterized by Pb and Zn, and magnetite. Magnetic measurements of soils are capable of differentiating sources of magnetic minerals and heavy metals from industrial processes, vehicle fleets and soil parent material. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Detecting the sensitivity of magnetic response on different pollution sources--A case study from typical mining cities in northwestern China.

    PubMed

    Wang, Bo; Xia, Dunsheng; Yu, Ye; Jia, Jia; Nie, Yan; Wang, Xin

    2015-12-01

    Rapid monitoring and discriminating different anthropogenic pollution is a key scientific issue. To detect the applicability and sensitivity of magnetic measurements for evaluating different industrial pollution in urban environment, characteristics of topsoil from three typical fast developing industrial cities (Jinchang, Baiyin and Jiayuguan in Gansu province, northwestern China) were studied by magnetic and geochemical analyses. The results showed that magnetic susceptibility was enhanced near industrial areas, and PSD-MD magnetite dominated the magnetic properties. Magnetic concentration parameters (χlf, SIRM, and χARM) showed different correlations with heavy metals and PLI in the three cities, indicating significantly different magnetic response to different pollution sources. Principal component analysis showed that ferrimagnetic minerals coexist with heavy metals of Fe, As, Cu, Pb, and Zn in Baiyin and Fe, V, Cu, Mn, Pb, and Cr in Jiayuguan. Fuzzy cluster analysis and regression analysis further indicated that the sensitivity of magnetic monitoring to fuel dust is higher than that to mineral dust near non-ferrous metal smelters, and fossil fuel consumption is an important factor for increasing magnetite content. In all the three cities, the sensitivity of magnetic monitoring to pollutants from steel plants is much higher than that from non-ferrous metal plants. Therefore, magnetic proxies provide a rapid means for detecting heavy metal contamination caused by multi-anthropogenic pollution sources in a large scale area, however, the sensitivity was controlled by pollution sources.

  14. Diversity and structure of a bacterial community in grassland soils disturbed by sheep grazing, in the Loess Plateau of northwestern China.

    PubMed

    Gou, Y N; Nan, Z B; Hou, F J

    2015-12-15

    The relationship between disturbance, biodiversity, and ecosystem function has been a hot topic recently in international ecological research, and a universally applicable model remains elusive. In this study, we assessed the diversity and structure of a bacterial community in grassland soils along a disturbance gradient due to sheep grazing. Bacteria were identified based on 16S rDNA gene libraries prepared from a 12-year field experiment that included four grazing, intensity treatments: no grazing, light grazing, moderate grazing and heavy grazing in the Loess Plateau of northwestern China. We found that diversity indices of bacterial 16S rDNA increased with grazing intensity, suggesting that disturbance led to higher bacterial diversity. The bacterial community structure, measured as species composition, was also affected by grazing. In addition, the change in soil bacterial community composition was maximum under heavy grazing, based on the Sorensen similarity index. Overall, the relationship between disturbance and bacterial diversity is complex, therefore, more studies are required to determine the possibility of using microbial diversity as an indicator of ecosystem stability.

  15. Comparative study on the antioxidant activities of extracts of Coreopsis tinctoria flowering tops from Kunlun Mountains, Xinjiang, north-western China.

    PubMed

    Yao, Xincheng; Gu, Chengzhi; Tian, Liping; Wang, Xinbing; Tang, Hui

    2016-01-01

    Coreopsis tinctoria flowering tops (CTFs) from the Kunlun Mountains in Xinjing (north-western China) have been used for tea production for about a century. This study aims to assess the antioxidant activities and total phenolic, flavonoid and proanthocyanidin contents of various solvent extracts of CTF. CTF was extracted using n-hexane, chloroform, ethyl acetate, n-butanol, 75% aqueous ethanol (AEE) and water. The antioxidant activities of the CTF extracts were investigated through DPPH, ABTS, *OH, *O2(-), total antioxidant capacity and reducing power assays. The results showed that n-butanol extract showed the highest contents of total phenols and flavonoids, with DPPH, ABTS and *OH radical-scavenging activities with IC50 values of 134, 90.72 and 13.8 μg mL(-1), respectively. The AEE demonstrated the strongest DPPH and ABTS radical-scavenging activities, with IC50 values of 103 and 75.16 μg mL(-1), respectively. Given its high antioxidant effect, CTF is a good source of natural antioxidants or functional food materials.

  16. Predicting available water of soil from particle-size distribution and bulk density in an oasis-desert transect in northwestern China

    NASA Astrophysics Data System (ADS)

    Li, Danfeng; Gao, Guangyao; Shao, Ming'an; Fu, Bojie

    2016-07-01

    A detailed understanding of soil hydraulic properties, particularly the available water content of soil, (AW, cm3 cm-3), is required for optimal water management. Direct measurement of soil hydraulic properties is impractical for large scale application, but routinely available soil particle-size distribution (PSD) and bulk density can be used as proxies to develop various prediction functions. In this study, we compared the performance of the Arya and Paris (AP) model, Mohammadi and Vanclooster (MV) model, Arya and Heitman (AH) model, and Rosetta program in predicting the soil water characteristic curve (SWCC) at 34 points with experimental SWCC data in an oasis-desert transect (20 × 5 km) in the middle reaches of the Heihe River basin, northwestern China. The idea of the three models emerges from the similarity of the shapes of the PSD and SWCC. The AP model, MV model, and Rosetta program performed better in predicting the SWCC than the AH model. The AW determined from the SWCCs predicted by the MV model agreed better with the experimental values than those derived from the AP model and Rosetta program. The fine-textured soils were characterized by higher AW values, while the sandy soils had lower AW values. The MV model has the advantages of having robust physical basis, being independent of database-related parameters, and involving subclasses of texture data. These features make it promising in predicting soil water retention at regional scales, serving for the application of hydrological models and the optimization of soil water management.

  17. The effects of a dry sand layer on groundwater recharge in extremely arid areas: field study in the western Hexi Corridor of northwestern China

    NASA Astrophysics Data System (ADS)

    Sun, Peng; Ma, Jinzhu; Qi, Shi; Zhao, Wei; Zhu, Gaofeng

    2016-09-01

    Evaporation capacity is an important factor that cannot be ignored when judging whether extreme precipitation events will produce groundwater recharge. The evaporation layer's role in groundwater recharge was evaluated using a lysimeter simulation experiment in the desert area of Dunhuang, in the western part of the Hexi Corridor in northwestern China's Gansu Province. The annual precipitation in the study area is extremely low, averaging 38.87 mm during the 60-year study period, and daily pan evaporation amounts to 2,486 mm. Three simulated precipitation regimes (normal, 10 mm; ordinary annual maximum, 21 mm; and extreme, 31 mm) were used in the lysimeter simulation to allow monitoring of water movement and weighing to detect evaporative losses. The differences in soil-water content to a depth of 50 cm in the soil profile significantly affected rainfall infiltration during the initial stages of rainfall events. It was found that the presence of a dry 50-cm-deep sand layer was the key factor for "potential recharge" after the three rainfall events. Daily precipitation events less than 20 mm did not produce groundwater recharge because of the barrier effect created by the dry sand. Infiltration totaled 0.68 mm and penetrated to a depth below 50 cm with 31 mm of rainfall, representing potential recharge equivalent to 1.7 % of the rainfall. This suggests that only extreme precipitation events offer the possibility of recharge of groundwater in this extremely arid area.

  18. Comparing meteorological records between mountainous and valley bottom sites in the upper reaches of the Heihe River, northwestern China: implications for dendroclimatology

    NASA Astrophysics Data System (ADS)

    Zeng, Qiao; Yang, Bao

    2017-04-01

    Tree-ring records from remote upland areas are widely used in climate reconstructions, but they are typically calibrated by meteorological data from low-lying areas. With the aim of assessing relationships between climatic records from mountainous and valley bottoms, this study compared meteorological records between mountainous sites (lower to upper elevations) and valley bottoms (Qilian (QL) and Yeniugou (YNG)) in the upper reaches of the Heihe River, northwestern China. We found that daily, 5-day, 10-day, and monthly mean air temperatures observed during a 4-year observational period in valley bottoms were strongly correlated ( R = 0.90-0.99) to their mountainous site counterparts. Additionally, temperature records from the QL meteorological station shared a higher percentage of variance with each mountainous site compared to YNG. Correlations of precipitation totals between valley bottoms and mountainous sites showed a similar pattern to temperatures. Furthermore, different time series of total rainfall in YNG can explain more variance than those from QL and were also more suitable representations of mountainous sites. Our results confirmed the reliability of utilizing monthly climatic records from valley bottoms to calibrate tree-ring records in mountainous sites. We also caution that when conducting fine-scale microcoring and dendrometer monitoring studies, lower correlations of short-term scale precipitation records between valley bottoms and mountainous sites may introduce unavoidable errors.

  19. Significant trade-off for the impact of Grain-for-Green Programme on ecosystem services in North-western Yunnan, China.

    PubMed

    Wang, Jitao; Peng, Jian; Zhao, Mingyue; Liu, Yanxu; Chen, Yunqian

    2017-01-01

    Ecological restoration can mitigate human disturbance to the natural environment and restore ecosystem functions. China's Grain-for-Green Programme (GFGP) has been widely adopted in the last 15years and exerted significant impact on land-use and ecosystem services. North-western Yunnan is one of the key areas of GFGP implementation in the upper Yangtze River. Promotion of ecosystem services in this region is of great importance to the ecological sustainability of Yangtze River watershed. In this study, remote sensing and modelling techniques are applied to analyse the impact of GFGP on ecosystem services. Results show that the transformation from non-irrigated farmland to forestland could potentially improve soil conservation by 24.89%. Soil conservation of restored forest was 78.17% of retained forest while net primary production (NPP) already reached 88.65%, which suggested different recovery rates of NPP and soil conservation. Increasing extent of GFGP implementation improved soil conservation but decreased NPP and water yield at sub-watershed scale, which revealed trade-offs between ecosystem services under ecological restoration. Future ecosystem management and GFGP policy-making should consider trade-offs of ecosystem services in order to achieve sustainable provision of ecosystem services.

  20. Seismic investigation of an ocean-continent transition zone in the northern South China Sea

    NASA Astrophysics Data System (ADS)

    Zhu, J.; Qiu, X.; Xu, H.; Zhan, W.; Sun, Z.

    2011-12-01

    Rifted continental margins and basins are mainly formed by the lithospheric extension. Thined lithosphere of passive continental margins results in decompression melt of magma and created oceanic crust and thined ocean-continent transition (OCT) zone. Two refraction profiles used ocean bottom seismometers deployed in the broad continental shelf and three multi-channel seismic reflection lines in the northern South China Sea, acquired by the ship "Shiyan 2" of the South China Sea Institute of Oceanology, Chinese Academy of Sciences in 2010, are processed and interpreted in this study. Seismic reflection lines cut through the Dongsha rise, Zhu-1 and Zhu-2 depression within a Tertiary basin, Pear River Mouth basin (called as Zhujiangkou basin). These tectonic features are clear imaged in the seismic reflection records. Numerous normal faults, cutted through the basement and related to the stretch of the northern South China Sea margin, are imaged and interpreted. Reflection characteristics of the ocean-continent transition (OCT) zone are summaried and outlined. The COT zone is mainly divided into the northern syn-rift subsidence zone, central volcano or buried volcano uplift zone and tilt faulted block near the South Chia Sea basin. Compared to the previous seismic reflection data and refraction velocity models, the segmentation range of the OCT zone is outlined, from width of about 225 km in the northeastern South China Sea , of 160 km in the central to of 110 km in the north-central South China Sea. Based on the epicenter distribution of sporadic and large than 6 magnitude earthquakes, it suggests the OCT zone in the northern South China Sea at present is still an active seismic zone.

  1. Detection and differentiation of pollution in urban surface soils using magnetic properties in arid and semi-arid regions of northwestern China.

    PubMed

    Wang, Bo; Xia, Dunsheng; Yu, Ye; Jia, Jia; Xu, Shujing

    2014-01-01

    Increasing urbanization and industrialization over the world has caused many social and environmental problems, one of which drawing particular concern is the soil pollution and its ecological degradation. In this study, the efficiency of magnetic methods for detecting and discriminating contaminates in the arid and semi-arid regions of northwestern China was investigated. Topsoil samples from six typical cities (i.e. Karamay, Urumqi, Lanzhou, Yinchuan, Shizuishan and Wuhai) were collected and a systematic analysis of their magnetic properties was conducted. Results indicate that the topsoil samples from the six cities were all dominated by coarse low-coercivity magnetite. In addition, the average magnetite contents in the soils from Urumqi and Lanzhou were shown to be much higher than those from Karamay, Yinchuan, Shizuishan and Wuhai, and they also have relatively higher χlf and χfd% when compared with cities in eastern China. Moreover, specific and distinctive soil pollution signals were identified at each sampling site using the combined various magnetic data, reflecting distinct sources. Industrial and traffic-derived pollution was dominant in Urumqi and Lanzhou, in Yinchuan industrial progress was observed to be important with some places affected by vehicle emission, while Karamay, Shizuishan and Wuhai were relatively clean. The magnetic properties of these latter three cities are significantly affected by both anthropogenic pollution and local parent materials from the nearby Gobi desert. The differences in magnetic properties of topsoil samples affected by mixed industrial and simplex traffic emissions are not obvious, but significant differences exist in samples affected by simplex industrial/vehicle emissions and domestic pollution. The combined magnetic analyses thus provide a sensitive and powerful tool for classifying samples according to likely sources, and may even provide a valuable diagnostic tool for discriminating among different cities.

  2. Convective scale structure and evolution of a squall line observed by C-band dual Doppler radar in an arid region of northwestern China

    NASA Astrophysics Data System (ADS)

    Liu, Liping; Zhuang, Wei; Zhang, Pengfei; Mu, Rong

    2010-09-01

    A long-lived and loosely organized squall line moved rapidly across Ürümqi, the capital city of Xinjiang Uygur Autonomous Region of China on 26 June 2005, generating hail and strong winds. The squall line was observed by a dual Doppler radar system in a field experiment conducted in 2004 and 2005 by the Chinese Academy of Meteorological Sciences and the local meteorological bureau in northwestern China. The 3D wind fields within the squall line were retrieved through dual Doppler analyses and a variational Doppler radar analysis system (VDRAS). The formation and structure of the squall line as well as the genesis and evolution of embedded convective cells were investigated. During its life period, the squall line consisted of six storm cells extending about 100 km in length, and produced hail of about 25 mm in diameter and strong surface winds up to 11 m s-1. Radar observations revealed a broad region of stratiform rain in a meso- β cyclone, with the squall line located to the west of this. Two meso- γ scale vortices were found within the squall line. Compared to typical squall lines in moist regions, such as Guangdong Province and Shanghai, which tend to be around 300-400 km in length, have echo tops of 17-19 km, and produce maximum surface winds of about 25 m s-1 and temperature variations of about 8°C this squall line system had weaker maximum reflectivity (55 dB Z), a lower echo top (13 km) and smaller extension (about 100 km), relatively little stratiform rainfall preceding the convective line, and a similar moving speed and temperature variation at the surface.

  3. Identification of Phytophthora species baited and isolated from forest soil and streams in northwestern Yunnan province, China

    USDA-ARS?s Scientific Manuscript database

    Phytophthora species were surveyed by collecting soil samples and placing bait leaves in selected streams during June - October in the years 2005, 2006 and 2010 at three sites in oak forests in Diqing Tibetan Autonomous Prefecture of NW Yunnan province, China. Seventy-three isolates of Phytophthora ...

  4. Hydrogeochemical and isotopic composition of groundwater in the Horgos River Watershed in the NorthWestern Ili Basin in Sinkiang Province, China

    NASA Astrophysics Data System (ADS)

    Jin, S. H.; Jiang, J. Y.; Rao, J. P.

    2016-08-01

    In this study, hydrogeochemical and stable environmental isotopic (oxygen-18 and deuterium) data of groundwater in the Horgos River watershed in the north-western Ili Basin were examined to determine the groundwater chemical characteristics, as well as the origins of the groundwater and surface water. The quaternary aquifer's structure and spatial distribution is complex. Hydrogeochemical data shows that the groundwater is alkaline due to the presence of bicarbonate as the dominant anion. In the north, the dominant groundwater cation was Ca2+ while Mg2+ ions were highest in the south. In addition, water types varied from HCO3-SO4-Ca and HCO3-SO4-Ca-Mg to HCO3-SO4-Mg-Ca and SO4-HCO3-Mg-Ca. Overall, the groundwater in this study showed high total hardness. The dissolving and evaporation inspissation were considered the main controlling factors. Isotopic data (oxygen-18 and deuterium) indicated that the Horgos River was the main recharge source for the groundwater, which rapidly infiltrated across sandstone macropores. Furthermore, surface water and shallow groundwater were significantly affected by evaporation.

  5. Comparison of modern pollen distribution between the northern and southern parts of the South China Sea.

    PubMed

    Luo, Chuanxiu; Chen, Muhong; Xiang, Rong; Liu, Jianguo; Zhang, Lanlan; Lu, Jun

    2015-04-01

    The authors conducted a palynological analysis based on different number of air pollen samples for the northern and southern parts of the South China Sea, respectively, in order to give a reference to reconstruct the paleoclimate of the area. (1) Fifteen air pollen samples were collected from the northern part of the South China Sea from August to September 2011, and 13 air pollen samples were collected from the southern part of the South China Sea in December 2011. The pollen types were more abundant in the north than in the south. The total pollen number and concentration in the north was 10 times more than that in the south, which may be because of the sampling season. Airborne pollen types and concentrations have a close relationship with wind direction and distance from the sampling point to the continent. (2) Seventy-four samples were collected from surface sediments in the northern part of the South China Sea in the autumn. Thirty-three samples were collected from surface sediments in the southern part of the South China Sea in the winter. Pollen concentrations in the north were nearly 10 times higher than that in the south. This is because trilete spores are transported by rivers from Hainan Island to the sea and also by the summer monsoon-forced marine current. (3) Ten air pollen samples and 10 surface sediments samples were selected for comparison. The pollen and spores in the air were mainly herbaceous and woody pollen, excluding fern spores, having seasonal pollen characteristics. Pollen in the surface sediments were mainly trilete, Pinus, and herbaceous, and may also show a combination of annual pollen characteristics.

  6. Comparison of modern pollen distribution between the northern and southern parts of the South China Sea

    NASA Astrophysics Data System (ADS)

    Luo, Chuanxiu; Chen, Muhong; Xiang, Rong; Liu, Jianguo; Zhang, Lanlan; Lu, Jun

    2015-04-01

    The authors conducted a palynological analysis based on different number of air pollen samples for the northern and southern parts of the South China Sea, respectively, in order to give a reference to reconstruct the paleoclimate of the area. (1) Fifteen air pollen samples were collected from the northern part of the South China Sea from August to September 2011, and 13 air pollen samples were collected from the southern part of the South China Sea in December 2011. The pollen types were more abundant in the north than in the south. The total pollen number and concentration in the north was 10 times more than that in the south, which may be because of the sampling season. Airborne pollen types and concentrations have a close relationship with wind direction and distance from the sampling point to the continent. (2) Seventy-four samples were collected from surface sediments in the northern part of the South China Sea in the autumn. Thirty-three samples were collected from surface sediments in the southern part of the South China Sea in the winter. Pollen concentrations in the north were nearly 10 times higher than that in the south. This is because trilete spores are transported by rivers from Hainan Island to the sea and also by the summer monsoon-forced marine current. (3) Ten air pollen samples and 10 surface sediments samples were selected for comparison. The pollen and spores in the air were mainly herbaceous and woody pollen, excluding fern spores, having seasonal pollen characteristics. Pollen in the surface sediments were mainly trilete, Pinus, and herbaceous, and may also show a combination of annual pollen characteristics.

  7. The Palaeoproterozoic Woodlands Formation of eastern Botswana-northwestern South Africa: lithostratigraphy and relationship with Transvaal Basin inversion structures

    NASA Astrophysics Data System (ADS)

    Eriksson, P. G.; Van Der Merwe, R.; Bumby, A. J.

    1998-11-01

    The Woodlands Formation (uppermost Pretoria Group) of eastern Botswana overlies thick quartzites of the Sengoma Formation (Magaliesberg Formation) and comprises a lower unit of interbedded mudrocks and fine-grained recrystallised quartzitic sandstones, succeeded by chaotic and very coarse-grained inferred slump deposits. Within the adjacent western region of South Africa, interbedded mudrocks and quartzitic sandstones stratigraphically overlying the Magaliesberg Formation are now assigned to the lower Woodlands Formation. Within the entire region, interference folding produced by northeast-southwest (F 1 and F 3) and northwest-southeast (F 2) compression, and concomitant faulting characterised inversion of the Pretoria Group basin. This deformation is of pre-Bushveld age and affected all units in the Pretoria Group, including the uppermost Silverton, Magaliesberg and Woodlands Formations, and intrusive Marico Hypabyssal Suite (pre-Bushveld) mafic sills. The Nietverdiend lobe of the Bushveld Complex, intrusive into this succession, was not similarly deformed. Movement along the major Mannyelanong Fault in the northwest of the study area post-dated Transvaal Basin inversion, after which the "upper Woodlands" chaotic slump deposits were formed. The latter must thus belong to a younger stratigraphical unit and is possibly analogous to apparently syntectonic sedimentary rocks (Otse Group) in the Otse Basin of eastern Botswana.

  8. Data from renewable energy assessments for resort islands in the South China Sea.

    PubMed

    Basir Khan, M Reyasudin; Jidin, Razali; Pasupuleti, Jagadeesh

    2016-03-01

    Renewable energy assessments for resort islands in the South China Sea were conducted that involves the collection and analysis of meteorological and topographic data. The meteorological data was used to assess the PV, wind and hydropower system potentials on the islands. Furthermore, the reconnaissance study for hydro-potentials were conducted through topographic maps in order to determine the potential sites suitable for development of run-of-river hydropower generation. The stream data was collected for 14 islands in the South China Sea with a total of 51 investigated sites. The data from this study are related to the research article "Optimal combination of solar, wind, micro-hydro and diesel systems based on actual seasonal load profiles for a resort island in the South China Sea" published in Energy (Khan et al., 2015) [1].

  9. [Degradation of main ecosystems in South China Sea and corresponding conservation countermeasures].

    PubMed

    Lan, Zhuhong; Chen, Guizhu

    2006-10-01

    South China Sea is a significant area of global biological diversity. Due to the long-term unreasonable exploitation and utilization, the habitat there degenerates obviously, and the biodiversity loses seriously. The estimated annual loss of mangrove area ranges from 0.5% to 3.5% , and that of seaweed area is from 20% to 50%. A total of 82% of coral reefs in the Sea display evident degradation. In this paper, a trans-boundary diagnostic analysis of ecosystem degradation in South China Sea was conducted, with the focus on mangrove, seaweed and coral reef. Based on the analysis of the destruction state of the existing ecosystems as well as the main causes of habitat degradation and its trans-boundary impacts, some countermeasures on habitat conservation and management were put forward, aimed to promote the cooperation both at national and at regional levels to implement appropriate approach to reverse the ecosystem degradation trend in South China Sea.

  10. Energy audit data for a resort island in the South China Sea.

    PubMed

    Basir Khan, M Reyasudin; Jidin, Razali; Pasupuleti, Jagadeesh

    2016-03-01

    The data consists of actual generation-side auditing including the distribution of loads, seasonal load profiles, and types of loads as well as an analysis of local development planning of a resort island in the South China Sea. The data has been used to propose an optimal combination of hybrid renewable energy systems that able to mitigate the diesel fuel dependency on the island. The resort island selected is Tioman, as it represents the typical energy requirements of many resort islands in the South China Sea. The data presented are related to the research article "Optimal Combination of Solar, Wind, Micro-Hydro and Diesel Systems based on Actual Seasonal Load Profiles for a Resort Island in the South China Sea" [1].

  11. Leaf morphology and cuticular features of Sphenophyllum in the Gigantopteris flora from South China.

    PubMed

    Yao; Liu; Mapes; Rothwell

    2000-06-01

    Permian specimens of Sphenophyllum with preserved cuticular anatomy have been discovered in Cathaysia and have prompted a detailed re-evaluation of the genus in the Gigantopteris flora in South China. New specimens are described and previously published material is re-examined to clarify taxonomic diversity and to establish geographic and stratigraphic ranges for each species. Recognized taxa include Sphenophyllum apiciserratum sp. nov., S. koboense Kobatake, S. meridionale sp. nov., S. minor (Sterzel) Gu and Zhi, S. sinocoreanum Yabe, S. cf. sinocoreanum Yabe, and S. aff. speciosum (Royle) McClelland. Cuticles of Sphenophyllum apiciserratum and S. koboense are hypostomatic with randomly disposed ordinary cells in intercostal regions. Specific concepts are clarified and unresolved taxonomic problems are discussed. The South China taxa are compared with those from Euramerican, Gondwanan and Angaran floras, and the South China Cathaysian species are found to be taxonomically distinct.

  12. Temporal and spatial distributions of TEC depletions with scintillations and ROTI over south China

    NASA Astrophysics Data System (ADS)

    Deng, Baichang; Huang, Jiang; Kong, Debao; Xu, Jie; Wan, Dehuan; Lin, Guoguo

    2015-01-01

    This study investigated the temporal and spatial distributions of TEC depletions with scintillations and ROTI over south China. Data were collected from two GPS receiver stations in south China from 2011 to 2012. Our results revealed that maxima of distribution of TEC depletions were observed in vernal and autumnal equinox months. During pre-midnight hours and in the region of northern crest of equatorial anomaly, deep TEC depletions (approximately 20 TECU) well coincided with the occurrences of intense scintillations (S4 > 0.5) and large ROTI (approximately 2). But around midnight hours or at the outer edge of northern anomaly crest, only shallow TEC depletions (<10 TECU) were recorded with small ROTI (<1) and no scintillation. Our results suggest that the temporal and spatial variability of TEC depletions during equinox months over south China could be considered as a representative of the evolution phase of the plasma bubbles during post-sunset hours.

  13. Data from renewable energy assessments for resort islands in the South China Sea

    PubMed Central

    Basir Khan, M. Reyasudin; Jidin, Razali; Pasupuleti, Jagadeesh

    2015-01-01

    Renewable energy assessments for resort islands in the South China Sea were conducted that involves the collection and analysis of meteorological and topographic data. The meteorological data was used to assess the PV, wind and hydropower system potentials on the islands. Furthermore, the reconnaissance study for hydro-potentials were conducted through topographic maps in order to determine the potential sites suitable for development of run-of-river hydropower generation. The stream data was collected for 14 islands in the South China Sea with a total of 51 investigated sites. The data from this study are related to the research article “Optimal combination of solar, wind, micro-hydro and diesel systems based on actual seasonal load profiles for a resort island in the South China Sea” published in Energy (Khan et al., 2015) [1]. PMID:26779562

  14. Energy audit data for a resort island in the South China Sea

    PubMed Central

    Basir Khan, M. Reyasudin; Jidin, Razali; Pasupuleti, Jagadeesh

    2015-01-01

    The data consists of actual generation-side auditing including the distribution of loads, seasonal load profiles, and types of loads as well as an analysis of local development planning of a resort island in the South China Sea. The data has been used to propose an optimal combination of hybrid renewable energy systems that able to mitigate the diesel fuel dependency on the island. The resort island selected is Tioman, as it represents the typical energy requirements of many resort islands in the South China Sea. The data presented are related to the research article “Optimal Combination of Solar, Wind, Micro-Hydro and Diesel Systems based on Actual Seasonal Load Profiles for a Resort Island in the South China Sea” [1]. PMID:26900590

  15. Heavy metal pollution in coastal areas of South China: a review.

    PubMed

    Wang, Shuai-Long; Xu, Xiang-Rong; Sun, Yu-Xin; Liu, Jin-Ling; Li, Hua-Bin

    2013-11-15

    Coastal areas of South China face great challenges due to heavy metal contamination caused by rapid urbanization and industrialization. In this paper, more than 90 articles on levels, distributions, and sources of heavy metals in sediments and organisms were collected to review the status of heavy metal pollution along coastal regions of South China. The results show that heavy metal levels were closely associated with local economic development. Hong Kong and the Pearl River Estuary were severely contaminated by heavy metals. However, concentrations of heavy metals in sediments from Hong Kong have continually decreased since the early 1990 s. High levels of heavy metals were found in biota from Lingdingyang in Guangdong province. Mollusks had higher concentrations of heavy metals than other species. Human health risk assessments suggested that levels of heavy metals in some seafood from coastal areas of South China exceeded the safety limit.

  16. Proterozoic polymetamorphism in the Quanji Block, northwestern China: Evidence from microtextures, garnet compositions and monazite CHIME ages

    NASA Astrophysics Data System (ADS)

    Wang, Qinyan; Pan, Yuanming; Chen, Nengsong; Li, Xiaoyan; Chen, Haihong

    2009-05-01

    The Quanji Block, situated close to the triple junction of three major Precambrian terranes in China (i.e., the North China Craton, the Yangtze Block and the Tarim Block), is composed of Precambrian metamorphic crystalline basement and an unmetamorphosed Mesozoic-Paleozoic sedimentary cover; it has been interpreted as a remnant continental fragment. Microtextural relationships, garnet trace element compositions, and monazite CHIME ages in paragneisses, schists and granitic leucosomes show two episodes of regional metamorphism in the Quanji Block basement. The first regional metamorphism and accompaning anatexis took place at ˜1.93 Ga; the second regional metamorphism occurred between ˜1.75 and ˜1.71 Ga. Mineral compositions of the first metamorphism, including those of monazite, were significantly disturbed by the second event. These two regional metamorphic episodes were most likely linked to assembly and breakup of the supercontinent Columbia, respectively.

  17. The rift to drift evolution of the South China Sea

    NASA Astrophysics Data System (ADS)

    Ranero, Cesar R.; Cameselle, Alejandra; Franke, Dieter; Barckhausen, Udo

    2016-04-01

    Re-processing with modern algorithms of multichannel seismic reflection records from the South China Sea provide novel images on the crustal structure of the continental margin and its boundary zone with the oceanic crust (COB). The selected re-processed seismic lines strike perpendicular to the margins' trend and cross the entire basin, providing complementary images of conjugated rift segments of the NW, SW, and E sub-basins. Re-processed sections image the post-rift and syn-rift sediment, and fault-bounded basement blocks, often also intra-crustal fault reflections that together provide detailed information of the tectonic structural style during rifting. Further, the largest imaging improvement has been obtained in the delineation of -very often- clear fairly continuous reflections from the crust-mantle boundary across the continental margin into the oceanic crust. The images show how crustal thickness and structure change in parallel to changes in the tectonic style of the deformation during the evolution of the rift. The interpreted COB occurs in regions where the tectonic style displays the most noticeable changes from segments where extension is dominated by normal faulting to segments where faulting is comparatively minor and the crust shows fairly gentle lateral thickness variations; these latter segments are interpreted as oceanic crust. The identification of the continental and oceanic tectonic domains permits to study the along-strike evolution in rifting processes and rift segmentation. Also, the comparison of the tectonic structure of the conjugated flanks of the continental rift across the ocean basins is used to understand the last stages of rifting and the relative importance of tectonic extension and magmatism in final break up and spreading initiation. Although there is ample evidence of important volcanism in the images, with some spectacular large conical volcanoes formed over continental crust and numerous sill-like reflections in the

  18. Currents on the Continental Shelf of Northern South China Sea

    NASA Astrophysics Data System (ADS)

    Tai, J.; Tang, T.

    2012-12-01

    The shelf current of northern South China Sea (SCS) is investigated by using moored observations. The short-term Acoustic Doppler Current Profiler (ADCP) array, which was deployed cross the shelf, and two long-term ADCPs, one on the shelf and another is at slope, are used to study the spatial structures and temporal variations of shelf current, respectively. The results indicate that the shelf current is quite variable. The tidal current varied in space and in time. For the diurnal tidal currents, the first baroclinic O1 tide dominated on the shelf but the first baroclinic K1 tide dominated at the slope. For the semi-diurnal tides, the barotropic M2 tide dominated on the shelf but first baroclinic mode dominated at the slope. The temporal variation on the shelf showed that barotropic mode is dominant in winter for both diurnal and semi-diurnal tide but only for semi-diurnal tides in summer. The sub-tidal current on the shelf is also variable. The wind played a critical role to drive the subtidal current on the shelf. The wind drove the Ekman transport first, and then piled up the water alone the coast. Finally the along-shelf geostrophic current driven by the seaward pressure gradient was seen. The southward run-off water from Taiwan Strait induced by typhoon, the eddy and the Kuroshio intrusion in the northern SCS also has impact on the current on the shelf and shelf break. The observation showed that SCS Warm Current (SCSWC), which was claimed as a persistent northeasterly flow, appeared/vanished with time. During the winter monsoon season, the headed wind SCSWC appeared only when the wind was relaxed (i.e. the wind stress less than 1.5 dyne/cm2); while the southwestward current was seen primarily when the wind intensified. Obviously, The SCSWC was a transient feature when the winter monsoon was prevailed. The northeastward current was seen frequently during the summer monsoon. Again, the wind caused sea level variation could be the main mechanism for the appear

  19. Wind wave variability in the South China Sea

    NASA Astrophysics Data System (ADS)

    Aboobacker, V. M.; Tkalich, P.; Gulev, S. K.; Grigorieva, V.

    2012-04-01

    Wind wave characteristics in South China Sea (SCS) are studied for the period 1953-2007 using gridded Voluntary Observing Ships (VOS) data within a rectangular domain 90° E - 130° E and 10°S - 30°N. Monthly VOS data are analyzed simultaneously and correlated with NCEP wind data of the same resolution. The trends and variability during the 55-year period are analyzed for wind and wave parameters. Empirical relationships between wind speed and wave parameters are derived for typical regions, including southern SCS, Gulf of Thailand, central SCS and northern SCS. Increasing trend is observed in wave heights during 1953-2007. It has been found that swells are sufficiently contributed to the significant wave heights in the SCS. The wind sea heights and wave periods are highly correlated with wind in the SCS, except for a few regions where the reports in VOS are considerably low. The correlation coefficient of wind sea heights amounts up to 0.86, whereas for the wind sea period reaches 0.82. The correlation coefficient between the wind speed and dominant wave period reaches 0.70, and between wind speed and wind sea period is up to 0.75. The 55-year mean wind speed shows that the wind speeds are higher (up to 6.4 m/s) at the central and northern part of the SCS, whereas those at the southern SCS and Gulf of Thailand are below 5 m/s. The 55-year mean SWH ranges up to 2.75m and the SWH is considerably higher at the northern SCS. A gradual increase in wave height is observed between the decades 1950s to 2000s. Interestingly, a northward shift in the intensity of SWH is observed. The southwest (SW) monsoon waves shows increasing trend in SWH, swell height and wind sea heights which are significantly higher at the northern SCS, however, similar pattern is not evident in the northeast (NE) monsoon waves, showing that the intensity of SW monsoon generated waves becomes increased in the recent decades. Variations associated with ENSO (El Nino Southern Oscillations) are

  20. A new species of Lophophysema (Porifera, Hexactinellida, Hyalonematidae) from the South China Sea.

    PubMed

    Gong, Lin; Li, Xinzheng; Qiu, Jian-Wen

    2014-11-19

    We describe Lophophysema eversa sp. nov. (Porifera, Hexactinellida, Hyalonematidae) based on a single specimen collected from the South China Sea at a depth of 3683 m. The new species can be distinguished from the three known congeners by its unusual body shape with basalia on the side of the body, the lack of macramphidiscs, the combination of the pinular pentactins having spiny tangential rays and the pinular ray of atrialia longer than dermalia and canalaria. This is the first record of the genus Lophophysema from the South China Sea. We also use a partial sequence of the 16S rRNA gene to confirm the family assignment of the new specimen.

  1. Non-linear Internal Wave Evolution in the South China Sea: 2005 Field Program

    DTIC Science & Technology

    2009-05-01

    code) 05/01/2009 Final 11/18/05 - 09/30/07 Non-linear Internal Wave Evolution in the South China Sea : 2005 Field Program N00014-05-1-0140 Pinkel...challenge was to see if the waves arriving at the western slopes of the South China Sea were in fact, propagating trans-basin from generating sites... Sea : 2005 Field Program Final Report: N00014-05-1-0140 Robert Pinkel Marine Physical Laboratory Scripps Institution of Oceanography

  2. Spatial Analysis of Air Quality Monitor Data in China, Japan, and South Korea

    NASA Astrophysics Data System (ADS)

    Rohde, Robert

    2016-04-01

    In 2015, Berkeley Earth published a widely-reported study concluding that air pollution contributes to 1.6 million deaths per year in China. This presentation will provide an update on that work with additional data for China and new analysis for South Korea and Japan. In China, two years of data from more than 1500 monitoring stations allows local trends to be estimated. Preliminary review indicates a trend towards improving air quality across most of China with decreasing emissions at most major population centers. Such improvements are consistent with tightening emissions standards and the decreasing usage of coal. In addition, new spatial analysis has been applied to ~900 monitoring sites in Japan and ~120 sites in South Korea. This new analysis provides information on air quality, pollutant source distributions, and implied mortality in these countries. Finally, boundary crossing fluxes in South Korea and Japan have been used to estimate the fraction of air pollution in Japan and South Korea that has being imported from sources in China.

  3. Study of southern CHAONAN sag lower continental slope basin deposition character in Northern South China Sea

    NASA Astrophysics Data System (ADS)

    Tang, Y.

    2009-12-01

    Northern South China Sea Margin locates in Eurasian plate,Indian-Australia plate,Pacific Plates.The South China Sea had underwent a complicated tectonic evolution in Cenozoic.During rifting,the continental shelf and slope forms a series of Cenozoic sedimentary basins,including Qiongdongnan basin,Pearl River Mouth basin,Taixinan basin.These basins fill in thick Cenozoic fluviolacustrine facies,transitional facies,marine facies,abyssal facies sediment,recording the evolution history of South China Sea Margin rifting and ocean basin extending.The studies of tectonics and deposition of depression in the Southern Chaonan Sag of lower continental slope in the Norther South China Sea were dealt with,based on the sequence stratigraphy and depositional facies interpretation of seismic profiles acquired by cruises of“China and Germany Joint Study on Marine Geosciences in the South China Sea”and“The formation,evolution and key issues of important resources in China marginal sea",and combining with ODP 1148 cole and LW33-1-1 well.The free-air gravity anomaly of the break up of the continental and ocean appears comparatively low negative anomaly traps which extended in EW,it is the reflection of passive margin gravitational effect.Bouguer gravity anomaly is comparatively low which is gradient zone extended NE-SW.Magnetic anomaly lies in Magnetic Quiet Zone at the Northern Continental Margin of the South China Sea.The Cenozoic sediments of lower continental slope in Southern Chaonan Sag can be divided into five stratum interface:SB5.5,SB10.5,SB16.5,SB23.8 and Hg,their ages are of Pliocene-Quaternary,late Miocene,middle Miocene,early Miocene,paleogene.The tectonic evolution of low continental slope depressions can be divided into rifting,rifting-depression transitional and depression stages,while their depositional environments change from river to shallow marine and abyssa1,which results in different topography in different stages.The topographic evolvement in the study

  4. The Levels and Distribution of TN, TP and TOC in the South China Sea

    NASA Astrophysics Data System (ADS)

    Wang, H.; Han, D.

    2012-04-01

    The marine biogeochemistries of carbon, nitrogen and phosphorous have come under increased scrutiny because of their close involvement in climate change and coastal eutrophication. The South China Sea is unique in that located in a subtropical zone, and therefore represents an important regime for biogeochemical studies. However, to our knowledge, few data are available for total nitrogen (TN), total phosphorous (TP) and total organic carbon (TOC) in South Sea, China. The present study aims to contribute to the knowledge of their status through investigating the level and distribution of TN, TP and TOC in South China Sea. A total of 108 seawater samples of 11 sites in south sea, china were collected during August 29- September 4, 2006. An automated and simultaneous method for determination of TN and TOC was applied to all seawater samples. The combined system allowed simultaneous determination for TOC and TN in the same sample using a single injection and provided low detection limits and excellent linear ranges for both TOC and TN. The risk of contamination has been remarkably reduced due to the minimal sample manipulation and automated analyses. And quantitative analyses of TP in seawater were accomplished by a typical chemical method. Concentration ranges of TN and TP were 0.06-0.67, and 0.003-0.071 mg/L, respectively, as well as that of TOC were 0.23-2.51mg/L. The values of TN and TP showed that the status of nutrition is relatively better in south china sea than other marine areas. Moreover, the upright change trend of TN concentration level as well as TP and TOC according to the experimental results at the total 11 sites are simultaneity studied. The concentration of TN initial increases with the increasing of the depth, later the value becomes almost constant. In contrast, the concentration of TOC reduces with the increasing of the depth, later the value becomes almost unchangeable. Compared with the trend of TN and TOC, that of TP appears relatively stable

  5. Paleohydrology of China Lake basin and the context of early human occupation in the northwestern Mojave Desert, USA

    NASA Astrophysics Data System (ADS)

    Rosenthal, Jeffrey S.; Meyer, Jack; Palacios-Fest, Manuel R.; Young, D. Craig; Ugan, Andrew; Byrd, Brian F.; Gobalet, Ken; Giacomo, Jason

    2017-07-01

    Considerable prior research has focused on the interconnected pluvial basins of Owens Lake and Searles Lake, resulting in a long record of paleohydrological change in the lower Owens River system. However, the published record is poorly resolved or contradictory for the period encompassing the terminal Pleistocene (22,000 to 11,600 cal BP) and early Holocene (11,600-8200 cal BP). This has resulted in conflicting interpretations about the timing of lacustrine high stands within the intermediate basin of China Lake, which harbors one of the most extensive records of early human occupation in the western Great Basin and California. Here, we report a broad range of radiocarbon-dated paleoenvironmental evidence, including lacustrine deposits and shoreline features, tufa outcrops, and mollusk, ostracode, and fish bone assemblages, as well as spring and other groundwater-related deposits (a.k.a. ;black mats;) from throughout China Lake basin, its outlet, and inflow drainages. Based on 98 radiocarbon dates, we develop independent evidence for five significant lake-level oscillations between 18,000 and 13,000 cal BP, and document the persistence of groundwater-fed wetlands from the beginning of the Younger Dryas through the early Holocene (12,900-8200 cal BP); including the transition from ground-water fed lake to freshwater marsh between about 13,000 and 12,600 cal BP. Results of this study support and refine existing evidence that shows rapid, high-amplitude oscillations in the water balance of the Owens River system during the terminal Pleistocene, and suggest widespread human use of China Lake basin began during the Younger Dryas.

  6. A revisit to the Higo terrane, Kyushu, Japan: The eastern extension of the North China-South China collision zone

    NASA Astrophysics Data System (ADS)

    Suga, Kenshi; Yui, Tzen-Fu; Miyazaki, Kazuhiro; Sakata, Shuhei; Hirata, Takafumi; Fukuyama, Mayuko

    2017-08-01

    The Higo and Manotani high-T metamorphic rocks belong to the Higo terrane, central Kyushu, Japan. This terrane has been suggested as the eastern extension of the North China-South China collision zone based mainly on the similar petrological and geochronological data to the north Dabie high-grade rocks. In this study, detrital zircon U-Pb dating for the Higo metamorphic rocks yielded a maximum depositional age of 197 Ma with a prominent component at 193-284 Ma (62-95%) and a subsidiary peak at 1847-1875 Ma (19-28%); whereas for the Manotani metamorphic rocks, the maximum depositional age is 263 Ma with a prominent component at 263-304 Ma (98%). These results suggest that the protoliths of the Higo and Manotani metamorphic rocks might be equivalent to those of the early-middle Jurassic Chizu and late Triassic Suo high-P metamorphic rocks, southwest Japan, respectively. The absence of middle Neoproterozoic detrital zircon (c. 700-825 Ma) is incompatible with a proposition that the proto-Japan might have been located close to the South China craton, where Permian-Jurassic sedimentary rocks contain a significant amount of middle Neoproterozoic detrital zircon. The zircon provenance of the Higo terrane, as well as of the Chizu and Suo belts, could therefore be the North China craton, suggesting that the Suo metamorphic rocks, including the Manotani metamorphic rocks, have formed at the subduction plate boundary in the east, which changed into the contemporaneous North China-South China collision plate boundary in the west, likely passing through the Korean Peninsula. The transformation of the Chizu and Suo metamorphic rocks to the Higo and Manotani metamorphic rocks can be accounted for by the oceanward advance of the volcanic arc during trench retreating. The Cretaceous high-T metamorphism and related igneous intrusions of the Higo terrane would be regarded as the initial phase of the Ryoke event.

  7. Isolation and Identification of Feline Herpesvirus Type 1 from a South China Tiger in China

    PubMed Central

    Sun, Heting; Li, Yuanguo; Jiao, Weiyi; Liu, Cunfa; Liu, Xiujuan; Wang, Haijun; Hua, Fuyou; Dong, Jianxiu; Fan, Shengtao; Yu, Zhijun; Gao, Yuwei; Xia, Xianzhu

    2014-01-01

    In 2012, an FHV-1-like virus was isolated from a tiger that presented with clinical signs of sialorrhea, sneezing and purulent rhinorrhea. Isolation was performed with the FK81 cell line, and the virus was identified by PCR, transmission electron microscopy (TEM), and the phylogenetic analysis of the partial thymidine kinase (TK) and glycoprotein B (gB) genes. A total of 253 bp of the TK gene and 566 bp of the gB gene were amplified from the trachea of the tiger by PCR/RT-PCR method. Phylogenetic analysis showed that the isolate belonged to the same cluster with other FHV-1 strains obtained from GenBank. Herpes-like viruses with an envelope and diameters of approximately 200 nm were observed in the culture supernatants of FK81 cells inoculated with samples from the tiger. The FHV-1 infection was confirmed by an animal challenge experiment in a cat model. Our finding extends the host range of FHV-1 and has implications for FHV-1 infection and South China tiger conservation. PMID:24590411

  8. Isolation and identification of feline herpesvirus type 1 from a South China tiger in China.

    PubMed

    Sun, Heting; Li, Yuanguo; Jiao, Weiyi; Liu, Cunfa; Liu, Xiujuan; Wang, Haijun; Hua, Fuyou; Dong, Jianxiu; Fan, Shengtao; Yu, Zhijun; Gao, Yuwei; Xia, Xianzhu

    2014-02-28

    In 2012, an FHV-1-like virus was isolated from a tiger that presented with clinical signs of sialorrhea, sneezing and purulent rhinorrhea. Isolation was performed with the FK81 cell line, and the virus was identified by PCR, transmission electron microscopy (TEM), and the phylogenetic analysis of the partial thymidine kinase (TK) and glycoprotein B (gB) genes. A total of 253 bp of the TK gene and 566 bp of the gB gene were amplified from the trachea of the tiger by PCR/RT-PCR method. Phylogenetic analysis showed that the isolate belonged to the same cluster with other FHV-1 strains obtained from GenBank. Herpes-like viruses with an envelope and diameters of approximately 200 nm were observed in the culture supernatants of FK81 cells inoculated with samples from the tiger. The FHV-1 infection was confirmed by an animal challenge experiment in a cat model. Our finding extends the host range of FHV-1 and has implications for FHV-1 infection and South China tiger conservation.

  9. Impacts of South East Biomass Burning on local air quality in South China Sea

    NASA Astrophysics Data System (ADS)

    Wai-man Yeung, Irene; Fat Lam, Yun; Eniolu Morakinyo, Tobi

    2016-04-01

    Biomass burning is a significant source of carbon monoxide and particulate matter, which is not only contribute to the local air pollution, but also regional air pollution. This study investigated the impacts of biomass burning emissions from Southeast Asia (SEA) as well as its contribution to the local air pollution in East and South China Sea, including Hong Kong and Taiwan. Three years (2012 - 2014) of the Hybrid Single Particle Lagrangian-Integrated Trajectory (HYSPLIT) with particles dispersion analyses using NCEP (Final) Operational Global Analysis data (FNL) data (2012 - 2014) were analyzed to track down all possible long-range transport from SEA with a sinking motion that worsened the surface air quality (tropospheric downwash from the free troposphere). The major sources of SEA biomass burning emissions were first identified using high fire emissions from the Global Fire Emission Database (GFED), followed by the HYSPLIT backward trajectory dispersion modeling analysis. The analyses were compared with the local observation data from Tai Mo Shan (1,000 msl) and Tap Mun (60 msl) in Hong Kong, as well as the data from Lulin mountain (2,600 msl) in Taiwan, to assess the possible impacts of SEA biomass burning on local air quality. The correlation between long-range transport events from the particles dispersion results and locally observed air quality data indicated that the background concentrations of ozone, PM2.5 and PM10 at the surface stations were enhanced by 12 μg/m3, 4 μg/m3 and 7 μg/m3, respectively, while the long-range transport contributed to enhancements of 4 μg/m3, 4 μg/m3 and 8 μg/m3 for O3, PM2.5 and PM10, respectively at the lower free atmosphere.

  10. Genome Sequence of Canine Parvovirus Strain SC02/2011, Isolated from a Puppy with Severe Diarrhea in South China

    PubMed Central

    Cheng, Yi; Ji, Yikuan; Wang, Yu; Sun, Leilei; Huang, Jiaxin

    2012-01-01

    A widespread hemorrhagic gastroenteritis in young dogs occurred in South China. A virulent field canine parvovirus (CPV) strain, SC02/2011, was isolated from a puppy showing enteric signs in Guangdong, China. The genome of CPV strain SC02/2011 was sequenced and analyzed, which will promote a better understanding of the molecular epidemiology and genetic diversity of CPV field isolates in South China. PMID:23166228

  11. Genome sequence of canine parvovirus strain SC02/2011, isolated from a puppy with severe diarrhea in south China.

    PubMed

    Ju, Chunmei; Cheng, Yi; Ji, Yikuan; Wang, Yu; Sun, Leilei; Huang, Jiaxin

    2012-12-01

    A widespread hemorrhagic gastroenteritis in young dogs occurred in South China. A virulent field canine parvovirus (CPV) strain, SC02/2011, was isolated from a puppy showing enteric signs in Guangdong, China. The genome of CPV strain SC02/2011 was sequenced and analyzed, which will promote a better understanding of the molecular epidemiology and genetic diversity of CPV field isolates in South China.

  12. A possible precursor of the South China Sea summer monsoon onset: Effect of the South Asian High

    NASA Astrophysics Data System (ADS)

    Liu, Boqi; Zhu, Congwen

    2016-10-01

    In climatology, the South China Sea (SCS) summer monsoon (SCSSM) generally onsets in Pentad 28 (16-20 May). The eastward extension of the South Asian High into the SCS in Pentad 27 is a possible precursor to the SCSSM onset. In the upper troposphere, the South Asian High (SAH) warms the air by inducing the positive potential vorticity advection, which strengthens precipitation over the southern SCS. When local convection becomes strong enough to decrease the vertical temperature gradient in Pentads 28-29, the upper level warming center overlies the subcloud warm region over the SCS to satisfy the requirement of the angular momentum conservation. A cross-equatorial flow then forms, together with strong vertical easterly wind shear and deep monsoon convection over the SCS, marking the full establishment of the SCSSM. The abrupt change in the SAH in May could therefore be an early indicator of the onset of the SCSSM.

  13. Interdecadal Variations of East Asian Monsoon as Inferred by Tree-ring Data From Northeastern Qaidam Basin, Northwestern China

    NASA Astrophysics Data System (ADS)

    Shao, X.; Huang, L.; Yin, Z.; Guo, Q.

    2006-12-01

    East Asian monsoon is crucial for modulating the climate in China. Especially, the summer monsoon is closely related to the severe flood and drought events in eastern China. To study the characteristics of summer monsoon a long-term record is needed. In this study we attempted to examine the interdecadal variations of East Asian monsoon by using tree-ring data. The summer monsoon index (Ism) for the period of 1873- 2000 was calculated using sea level pressure data. Firstly, we calculated the difference (ΔP) of the sea level pressure between the land (110ºE) and sea (160ºE) from 10ºN to 50ºN with 5º intervals. Then the ΔP values that are smaller than or equal to -5 hPa in June, July and August were summed and defined as the Ism. By this definition Ism values greater than 1.0 represent strong monsoon conditions, and vice versa. Sea level pressure data prior to 1951 were obtained from the Meteorological Office of United Kingdom, and that afterwards were from the NCEP data set. The tree ring data of Qilian junipers (Sabina przewalskii Kom.) are from the northeastern part of the Qaidam Basin, located along the northeastern margin of the Qinghai-Tibetan Plateau. These tree-ring data have been used to reconstruct local precipitation and soil moisture conditions. Previous studies have revealed that there was a teleconnection in rainfall between eastern China and the Qinghai-Tibetan Plateau. We examined the relationships of the ring-width series with the Ism series over the common period of 1873-2000 AD. We found that the tree-ring widths were statistical significantly correlated with Ism. These negative correlations increased significantly after a low-pass filter was used for both data sets, indicating very good potential for reconstruction of low-frequency variations of Ism in the past. Variability of the Ism series and ring-width series were examined using power spectrum analysis and wavelet transformation. The reconstructed Ism values during the period 1440

  14. Rock magnetic properties and paleoenvironmental implications of an 8-Ma Late Cenozoic terrigenous succession from the northern Tian Shan foreland basin, northwestern China

    NASA Astrophysics Data System (ADS)

    Lu, Honghua; Zhang, Weiguo; Li, Youli; Dong, Chenyin; Zhang, Tianqi; Zhou, Zuyi; Zheng, Xiangmin

    2013-12-01

    In the northern Tian Shan foreland basin, northwestern China, the thick Cenozoic terrigenous succession is crucial for paleoclimate-environmental reconstruction of the Asian interior. Here we present a detailed rock magnetic investigation on 245 samples from the ~ 1200-m-thick Neogene Taxi He section with a magnetostratigraphic age span of ca. 8.0 to 2.0 Ma in the northern Tian Shan foreland basin. Our rock magnetic results indicate that the significant variations in composition, concentration and grain size of magnetic minerals occurred at ca. 6.0, 3.7 and 2.7 Ma. The comparable compositions of rare earth elements (REEs) throughout the Neogene Taxi He section suggest no significant modification of the source materials during the interval between ca. 8.0 and 2.0 Ma, and thus sediment provenance is not regarded as responsible for these observed variations in rock magnetic properties. Our further analyses show that the variations in magnetic properties of the Taxi He section are casually linked mainly with lithofacies transition due to range encroachment into foreland basin as well as climate aridification. Identified enhancement of aridification was chronologically constrained at ca. 6.0 and 2.7 Ma. Such climate events are important archives for reconstructing the Late Cenozoic paleoclimatic history of the Asian interior. Further comparison between different paleoclimate records clearly indicates that magnetic parameters such as S- 100mT are potentially effective proxy indices for paleoclimate-environmental reconstruction in the Tian Shan foreland basins and the nearby areas.

  15. Holocene climate changes in the central Asia mountain region inferred from a peat sequence from the Altai Mountains, Xinjiang, northwestern China

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Meyers, Philip A.; Liu, Xingtu; Wang, Guoping; Ma, Xuehui; Li, Xiaoyu; Yuan, Yuxiang; Wen, Bolong

    2016-11-01

    A continuous peat sequence collected in the Altai Mountains, Xinjiang Province, northwestern China, provides a new opportunity to reconstruct the Holocene climate history in the arid central mountain region of Asia. Based on AMS 14C dating, high resolution records of the humification degree and n-alkane distributions reveal that the region experienced a relatively warm and dry early Holocene (10.0-8.0 ka) and a cold and wet early mid-Holocene (8.0-6.3 ka), followed by a warm and dry mid-Holocene (6.3-5.5 ka). A shift to cold and wet conditions occurred between 5.5 and 4.0 ka, and then the climate entered into a warmer period from 4.0 to 2.5 ka. In the late Holocene (2.5-1.0 ka), the region experienced a colder and wetter climate. A gradual shift to warm and dry conditions occurred during the last 1.0 ky in this region. The regional climate patterns have been generally dominated by alternations of warm-dry and cold-wet episodes during the Holocene that were quite different from the warm-wet and cool-dry episodes in the Asian summer monsoon region. Regional comparisons indicate that the climate changes in arid central Asia have been mainly influenced by the North Atlantic Ocean sea surface temperatures (SSTs) via the westerlies. However, owing to the mountainous character of the study areas, glacial meltwater, and other local factors, the climate changes in the Altai Mountains region have not always been concordant with variations of North Atlantic Ocean SSTs. We postulate that the history of moisture balance between regional precipitation, glacier and snow meltwater, and evaporation has been modulated by air temperatures that were mainly influenced by changes in the summer insolation of the Northern Hemisphere.

  16. Impact of HLA-G 14-bp polymorphism on acute rejection and cytomegalovirus infection in kidney transplant recipients from northwestern China.

    PubMed

    Jin, Zhan-Kui; Xu, Cui-Xiang; Tian, Pu-Xun; Xue, Wu-Jun; Ding, Xiao-Ming; Zheng, Jin; Ding, Chen-Guang; Ge, Guan-Qun; Mao, Tian-Ci; Lin, Yuan

    2012-10-01

    Human leukocyte antigen (HLA)-G plays an important role in promoting transplant tolerance and helping human cytomegalovirus (CMV) to subvert host defenses. Strong evidence suggests that HLA-G 14-bp insertion/deletion polymorphism influences the stability of HLA-G mRNAs and levels of protein expression. We hypothesized that HLA-G 14-bp polymorphism of recipients has an influence on the risk of acute rejection (AR) and CMV infection. We investigated the impact of HLA-G 14-bp polymorphism on a total of 363 unrelated Chinese Han individuals who included 42 kidney transplant recipients with AR, 43 recipients with CMV infection, 102 recipients with stable allograft function (STA), and 176 healthy controls (HC). No statistically significant difference was found between all kidney transplant patients and HC (P=0.149). But, our data showed an increased frequency of homozygous genotype +14/+14 bp (P(c)=0.004) and allele +14 bp (P(c)=0.002) in patients with AR when compared with STA, with the odds ratio of 3.17 and 2.28, respectively. Moreover, we found that the frequency of the -14/-14 bp genotype (P(c)=0.008) and the -14 bp allele (P(c)=0.016) was increased in patients with CMV infection when compared with STA, with the OR of 2.66 and 1.96, respectively. Multivariate analysis further demonstrated that HLA-G homozygous +14 bp and -14 bp genotypes were an independent risk factor for allograft rejection and CMV infection, respectively. In conclusion, this study identified an important genetic risk factor for acute allograft rejection, and it was the first to show a significant correlation between HLA-G 14-bp polymorphism and CMV infection after kidney transplantation from northwestern China. Crown Copyright © 2012. Published by Elsevier B.V. All rights reserved.

  17. Reconstruction of Soil Moisture and Vegetation Water Use Conditions Based on Tree-Ring Widths From Qilian Juniper in Qaidam Basin, Northwestern China

    NASA Astrophysics Data System (ADS)

    Yin, Z.; Shao, X.; Liang, E.; Qin, N.

    2005-12-01

    Tree-ring widths have been used widely in studies of environmental changes and reconstructions of past climate. Eleven tree-ring chronologies of approximately 800-1500 years long were developed from Qilian juniper (Sabina przewalskii Kom.) for the eastern part of the Qaidam Basin, northwestern China. The study area is located in an arid/semi-arid region with desert and dry grassland vegetation, but sparse juniper trees can be found on mountain slopes of 3600-4200 m above sea level, along the northeastern margin of the Tibetan Plateau. Previous studies have revealed that ring widths are positively correlated to May and June precipitation, but negatively correlated to temperature of the same months in this region, indicating that water use stress is the most limiting factor for tree growth during the growing season. We performed water balance modeling based on 1955-2002 meteorological data. We found that the tree-ring width is strongly correlated with variables representing soil moisture conditions obtained from the model. Specifically we considered actual evapotranspiration representing the combined effect of water use demand and moisture availability, deficit as the difference between potential evapotranspiration and actual evapotranspiration, representing the severity of water use shortage, and relative soil moisture as the measure of moisture availability. For certain individual months, such as May and June, and various bi-monthly and seasonal combinations (e.g., May-June, April-July, January to July, and July of previous year to current June), the tree-ring chronologies can explain more than 70% of the variation in the soil moisture variables in regression analysis, indicating very good potential for reconstruction of regional soil moisture conditions in the past.

  18. Sensitivity of growth and biomass allocation patterns to increasing nitrogen: a comparison between ephemerals and annuals in the Gurbantunggut Desert, north-western China.

    PubMed

    Zhou, Xiaobing; Zhang, Yuanming; Niklas, Karl J

    2014-02-01

    Biomass accumulation and allocation patterns are critical to quantifying ecosystem dynamics. However, these patterns differ among species, and they can change in response to nutrient availability even among genetically related individuals. In order to understand this complexity further, this study examined three ephemeral species (with very short vegetative growth periods) and three annual species (with significantly longer vegetative growth periods) in the Gurbantunggut Desert, north-western China, to determine their responses to different nitrogen (N) supplements under natural conditions. Nitrogen was added to the soil at rates of 0, 0.5, 1.0, 3.0, 6.0 and 24.0 g N m(-2) year(-1). Plants were sampled at various intervals to measure relative growth rate and shoot and root dry mass. Compared with annuals, ephemerals grew more rapidly, increased shoot and root biomass with increasing N application rates and significantly decreased root/shoot ratios. Nevertheless, changes in the biomass allocation of some species (i.e. Erodium oxyrrhynchum) in response to the N treatment were largely a consequence of changes in overall plant size, which was inconsistent with an optimal partitioning model. An isometric log shoot vs. log root scaling relationship for the final biomass harvest was observed for each species and all annuals, while pooled data of three ephemerals showed an allometric scaling relationship. These results indicate that ephemerals and annuals differ observably in their biomass allocation patterns in response to soil N supplements, although an isometric log shoot vs. log root scaling relationship was maintained across all species. These findings highlight that different life history strategies behave differently in response to N application even when interspecific scaling relationships remain nearly isometric.

  19. Identifying the origin and geochemical evolution of groundwater using hydrochemistry and stable isotopes in Subei Lake Basin, Ordos energy base, Northwestern China

    NASA Astrophysics Data System (ADS)

    Liu, F.; Song, X.; Yang, L.; Zhang, Y.; Han, D.; Ma, Y.; Bu, H.

    2014-05-01

    A hydrochemical and isotopic study was conducted in Subei Lake Basin, northwestern China, to identify the origin and geochemical evolution of groundwater. Water samples were collected, major ions and stable isotopes (δ18O, δ D) were analyzed. In terms of hydrogeological conditions in study area, groundwater can be classified into three types: the Quaternary groundwater, the shallow Cretaceous groundwater, the deep Cretaceous groundwater. Piper diagram and correlation analysis were used to reveal the hydrochemical characteristics of water resources. The dominant water type of lake water was Na-Cl type, which was controlled by strong evaporation and recharge from overland flow and groundwater; the predominant hydrochemical types for groundwater were Ca-HCO3, Na-HCO3, and mixed Ca · Na · Mg-HCO3 types, the groundwater chemistry is mainly controlled by dissolution/precipitation of anhydrite, gypsum, halite and calcite. The dedolomitization and cation exchange are also important factors. Rock weathering is confirmed to play a leading role in the mechanisms responsible for the chemical compositions of groundwater. The stable isotopic values of oxygen and hydrogen in groundwater are close to the local meteoric water line, showing that groundwater is of meteoric origin. The deep Cretaceous groundwater is depleted in heavy isotopes, compared to shallow Cretaceous groundwater. The hydrogen and oxygen isotopes signatures in deep Cretaceous groundwater may show a paleorecharge effect that the deep Cretaceous groundwater was recharged during a geologic period when the climate was wetter and colder than today. Due to strong evaporation effect and dry climatic conditions, heavy isotopes are more enriched in lake water than groundwater. The hydrochemical and isotopic information of utmost importance has been provided to decision-makers by the present study so that a sustainable water resources management policy could be designed for the Ordos energy base.

  20. δ18O and δ13C records from a Cenozoic sedimentary sequence in the Lanzhou Basin, Northwestern China: Implications for palaeoenvironmental and palaeoecological changes

    NASA Astrophysics Data System (ADS)

    Li, Baofeng; Sun, Donghuai; Wang, Xin; Zhang, Yuebao; Hu, Wenwei; Wang, Fei; Li, Zaijun; Ma, Zhiwei; Liang, Baiqing

    2016-08-01

    In northwestern China, carbonate δ18O variation has been closely associated with evaporation and precipitation, whereas the variation of carbonate δ13C generally reflects patterns of palaeovegetation. Located within the transitional zone between the Chinese Loess Plateau and the Tibetan Plateau, the Lanzhou Basin has developed a continuous sequence of Cenozoic sediments which have been subjected to detailed sedimentological and high-resolution magnetostratigraphic analyses. In the present study, pedogenic carbonate O and C isotopic analyses were obtained throughout the entire Cenozoic sequence. The δ18O record exhibits a general positive trend with several abrupt changes. A dramatic positive shift in the δ18O record at ∼33 Ma indicates the initiation of the aridification process within the basin, which was likely associated with the late Eocene westward retreat of the Tethys Sea and global cooling. Two significant positive shifts in the δ18O record at ∼22 Ma and ∼3.5 Ma are synchronous with major increases in aeolian dust deposition on the Chinese Loess Plateau and in the North Pacific Ocean, suggesting the intensified aridity of the Asian interior, which is likely related to the stepwise uplift of the Tibetan Plateau via the blocking of water vapour pathways. The δ13C values exhibit a weak positive trend with a remarkable shift at ∼3.5 Ma. This trend is likely related to a decrease in vegetation density in response to the ongoing Cenozoic aridification, whereas the shift at ∼3.5 Ma may reflect the large-scale expansion of C4 plants.

  1. Hydrological and land use control of watershed exports of dissolved organic matter in a large arid river basin in northwestern China

    NASA Astrophysics Data System (ADS)

    Hu, Yue; Lu, YueHan; Edmonds, Jennifer W.; Liu, Chuankun; Wang, Sai; Das, Oindrila; Liu, Jie; Zheng, Chunmiao

    2016-02-01

    We evaluated variation in dissolved organic matter (DOM) export as a function of hydrology and land use from a large arid river basin in northwestern China. Two soil-derived, humic-like (C1 and C2) and three protein-like fluorescence components (C3, C4, and C5) were identified. During high discharges, river water DOM had higher values of DOC concentration, percent humic fluorescence, and humification index, but lower values of fluorescence index and percent protein fluorescence than found at base flow, suggesting that flow paths shifted to shallower depths flushing out topsoil organic matter. Loading of DOC and soil-derived humic fluorescence were driven largely by discharge, with values over 10 times higher during high discharges than at base flow. Furthermore, both δ13C-DOC and C1 at high flows positively correlated with %agricultural lands within 1 km river buffers, demonstrating that near-river agricultural activities enhanced storm export of soil DOM. At base flow, C4 positively correlated with %agricultural lands, showing stimulation of aquatic bacterial carbon production as a result of elevated nutrient inputs from agricultural lands. Percent contributions of humic fluorescence in groundwater varied with well depths in shallow wells, but this pattern was not observed for deeper groundwater, suggesting that humic DOM could serve as a water source tracer indicating deeper aquifers were isolated from river water and shallow groundwater. Together, our data demonstrate that hydrology and land use controlled the sources and amount of riverine DOM in this large agricultural basin and that regulating storm runoff and near-river agricultural activities should be incorporated in ecosystem-based management of water resources.

  2. Vertical distributions of radionuclides ((239+240)Pu, (240)Pu/(239)Pu, and (137)Cs) in sediment cores of Lake Bosten in Northwestern China.

    PubMed

    Liao, Haiqing; Bu, Wenting; Zheng, Jian; Wu, Fengchang; Yamada, Masatoshi

    2014-04-01

    Artificial radionuclides ((137)Cs, (239+240)Pu, (241)Pu, (241)Am) deposited in lacustrine sediments have been used for dating as well as radionuclide source identification. In the present work, we investigated the vertical distributions of (239+240)Pu and (137)Cs activities, (240)Pu/(239)Pu atom ratios, and (239+240)Pu/(137)Cs activity ratios in sediment cores collected from Lake Bosten, which is the lake closest to the Lop Nor Chinese Nuclear Weapon Test site in northwestern China. Uniformly high concentrations of (239+240)Pu and (137)Cs were found in the upper layers deposited since 1964 in the sediment cores, and these were controlled by the resuspension of soil containing radionuclides from the nearby land surface. As the Chinese nuclear tests varied remarkably in yield, the mixing of the tropospheric deposition from these tests and the stratospheric deposition of global fallout has led to a (240)Pu/(239)Pu atom ratio that is similar to that of global fallout and to a (239+240)Pu/(137)Cs activity ratio that is slightly higher than that of global fallout. However, a low (240)Pu/(239)Pu atom ratio of 0.080 and high (239+240)Pu/(137)Cs activity ratio of 0.087, significantly different from the global fallout values, were observed in one sediment core (07BS10-2), indicating the inhomogenous tropospheric deposition from the Chinese nuclear tests in Lake Bosten during 1967-1973. These results are important to understand the influence of the CNTs on the radionuclide contamination in Lake Bosten.

  3. The pore structure and fractal characteristics of shales with low thermal maturity from the Yuqia Coalfield, northern Qaidam Basin, northwestern China

    NASA Astrophysics Data System (ADS)

    Hou, Haihai; Shao, Longyi; Li, Yonghong; Li, Zhen; Zhang, Wenlong; Wen, Huaijun

    2016-12-01

    The continental shales from the Middle Jurassic Shimengou Formation of the northern Qaidam Basin, northwestern China, have been investigated in recent years because of their shale gas potential. In this study, a total of twenty-two shale samples were collected from the YQ-1 borehole in the Yuqia Coalfield, northern Qaidam Basin. The total organic carbon (TOC) contents, pore structure parameters, and fractal characteristics of the samples were investigated using TOC analysis, low-temperature nitrogen adsorption experiments, and fractal analysis. The results show that the average pore size of the Shimengou shales varied from 8.149 nm to 20.635 nm with a mean value of 10.74 nm, which is considered mesopore-sized. The pores of the shales are mainly inkbottle- and slit-shaped. The sedimentary environment plays an essential role in controlling the TOC contents of the low maturity shales, with the TOC values of shales from deep to semi-deep lake facies (mean: 5.23%) being notably higher than those of the shore-shallow lake facies (mean: 0.65%). The fractal dimensions range from 2.4639 to 2.6857 with a mean of 2.6122, higher than those of marine shales, which indicates that the pore surface was rougher and the pore structure more complex in these continental shales. The fractal dimensions increase with increasing total pore volume and total specific surface area, and with decreasing average pore size. With increasing TOC contents in shales, the fractal dimensions increase first and then decrease, with the highest value occurring at 2% of TOC content, which is in accordance with the trends between the TOC and both total specific surface area and total pore volume. The pore structure complexity and pore surface roughness of these low-maturity shales would be controlled by the combined effects of both sedimentary environments and the TOC contents.

  4. The role of anthropogenic and natural factors in shaping the geochemical evolution of groundwater in the Subei Lake basin, Ordos energy base, Northwestern China.

    PubMed

    Liu, Fei; Song, Xianfang; Yang, Lihu; Han, Dongmei; Zhang, Yinghua; Ma, Ying; Bu, Hongmei

    2015-12-15

    Groundwater resources are increasingly exploited for industrial and agricultural purposes in many arid regions globally, it is urgent to gain the impact of the enhanced anthropogenic pressure on the groundwater chemistry. The aim of this study was to acquire a comprehensive understanding of the evolution of groundwater chemistry and to identify the impact of natural and anthropogenic factors on the groundwater chemistry in the Subei Lake basin, Northwestern China. A total of 153 groundwater samples were collected and major ions were measured during the three campaigns (August and December 2013, May 2014). At present, the major hydrochemical facies in unconfined groundwater are Ca-Mg-HCO3, Ca-Na-HCO3, Na-Ca-HCO3, Na-HCO3, Ca-Mg-SO4 and Na-SO4-Cl types, while the main hydrochemical facies in confined groundwater are Ca-Mg-HCO3, Ca-Na-HCO3, Na-Ca-HCO3, Ca-HCO3 and Na-HCO3 types. Relatively greater seasonal variation can be observed in the chemical constituents of confined groundwater than that of unconfined groundwater. Rock weathering predominates the evolution of groundwater chemistry in conjunction with the cation exchange, and the dissolution/precipitation of gypsum, halite, feldspar, calcite and dolomite are responsible for the chemical constituents of groundwater. Anthropogenic activities can be classified as: (1) groundwater overexploitation; (2) excessive application of fertilizers in agricultural areas. Due to intensive groundwater pumping, the accelerated groundwater mineralization resulted in the local changes in hydrochemical facies of unconfined groundwater, while the strong mixture, especially a large influx of downward leakage from the unconfined aquifer into the confined aquifer, played a vital role in the fundamental variation of hydrochemical facies in confined aquifer. The nitrate contamination is mainly controlled by the local hydrogeological settings coupled with the traditional flood irrigation. The deeper insight into geochemical evolution of

  5. Eastern Iowa, Northwestern Illinois

    NASA Image and Video Library

    1973-06-22

    SL2-10-250 (May-June 1973) --- A vertical view of eastern Iowa and northwestern Illinois, as photographed from Skylab space station in Earth orbit. Davenport, Burlington and Muscatine, Iowa; and Rock Island and Moline, Illinois can be delineated on opposite sides of the Mississippi River. The Iowa River and tributaries of it can also be delineated. This photograph was taken with one of six lenses of the Itek-furnished Multispectral Photographic Facility Experiment S190-A mounted in the Multiple Docking Adapter (MDA) of the space station. A six-inch lens, using 70mm medium speed Ektachrome (SO-356) film, was used. Agencies participating with NASA on the EREP project are the Departments of Agriculture, Commerce and Interior; the Environmental Protection Agency and the Corps of Engineers. All EREP photography is available to the public through the Department of Interior's Earth Resources Observations Systems Data Center, Sioux Falls, South Dakota, 57198. Photo credit: NASA

  6. Sources and Depositions of Atmospheric Trace Metals in PM2.5 over East China Seas and Northwestern Pacific Ocean

    NASA Astrophysics Data System (ADS)

    Zheng, M.; Yan, C.; Guo, X.; Gao, H.; Yao, X.

    2016-12-01

    Previous studies have indicated that trace metals may have significant effects on marine ecosystem. Atmospheric transport of continental aerosols and deposition of marine aerosols are one of the most important ways for trace metals from anthropogenic processes transferred to sea. One Chinese Comprehensive Ocean Experiment by R/V "Dong Fang Hong 2" of Ocean University of China was conducted over East China Seas and West Pacific in spring (from 30 March to 6 May) of 2015. An online multi-metal monitor (Xact 625, Copper Environmental Sciences, LLC) and single particle aerosol mass spectrometer (SPAMS), equipped with PM2.5 cyclone inlets during the cruise were onboard to conduct high time-resolution measurement on metals over these regions. Totally, 23 metals (e.g., Ca, Cu, Fe, Mn, K, Ni, Pb, Se, Zn, and V) were continuously and simultaneously measured with a time resolution of 1 to 2 hour. Therefore, chemical characteristics and spatial distribution of trace metals in marine aerosol were further investigated. In consideration of data quality, only 15 metals were further used and discussed. Our preliminary results showed that the concentrations of the sum of 15 metals ranged from 50 ng/m3 to 3 μg/m3 in this region, and metals inshore tend to have higher concentrations than offshore. The metals detected could be classified into four categories based on their spatial distributions. Source regions were identified by total potential source contribution function (TPSCF) model for each kind of metals. Size distribution of metals were analyzed by SPAMS. Furthermore, dry deposition of metals over this region were calculated and discussed, with a fixed small dry deposition velocity and also with consideration of size-dependent particle dry deposition velocities.

  7. Tension in the South China Sea: Why the Philippines is Challenging China’s Improved Military Might

    DTIC Science & Technology

    2013-12-01

    Armed Forces of the Philippines (AFP), Visiting Forces Agreement (VFA), Joint Marine Seismic Undertaking (JMSU) 15. NUMBER OF PAGES 75 16. PRICE...Capability Upgrade Program JMSU Joint Marine Seismic Undertaking NISP National Internal Security Plan PRC People’s Republic of China SCS South...8 Ibid., 159. 9 Ibid. 5 Chinese patrol boats had “deliberately cut a seismic cable being towed by a survey ship in waters claimed by Vietnam

  8. Multiple origins for the Middle Jurassic to Early Cretaceous high-K calc-alkaline I-type granites in northwestern Fujian province, SE China and tectonic implications

    NASA Astrophysics Data System (ADS)

    Wang, Guo-Chang; Jiang, Yao-Hui; Liu, Zheng; Ni, Chun-Yu; Qing, Long; Zhang, Qiao; Zhu, Shu-Qi

    2016-03-01

    A comprehensive study of zircon U-Pb dating and in situ Hf isotopes, whole-rock major and trace element geochemistry and Sr-Nd isotopes was carried out for three late Mesozoic granitic plutons (Waitun, Shipi and Taiyuan) in northwestern Fujian province, SE China. We assess the origin of the granites and their relationship to the evolution of the late Mesozoic volcanic-intrusive complex belt in SE China. LA-ICP-MS zircon U-Pb dating shows that three plutons were emplaced in the Middle Jurassic to Early Cretaceous (168-109 Ma), in which the Waitun and Shipi plutons are intrusive complexes. All the plutons are composed of high-K calc-alkaline I-type granites with a great diversity in elemental and isotopic compositions. The granites have SiO2 contents of 68.3-78.5 wt.%, showing a gradual decrease in initial 87Sr/86Sr (0.7181 to 0.7091) and increase in εNd (T) (- 16.7 to - 8.1) and εHf (T) (in-situ zircon) (- 20.6 to - 6.9) with decreasing emplacement ages. Geochemical data suggest that the Middle Jurassic ( 168 Ma) Waitun granites are of purely crustal origin, derived by partial melting of a mixed source of Paleoproterozoic metaigneous ( 78%) and metasedimentary ( 22%) rocks at a depth of 30-40 km triggered by underplating of basaltic magma. Mixing of such crustal melts with about 10% basaltic magma could account for the origin of the Late Jurassic ( 161 Ma) Waitun granites. The Late Jurassic ( 156 Ma) Shipi and Early Cretaceous ( 134 Ma) Taiyuan granites were produced by extensive fractional crystallization of primary crustal melts, the source of which show relatively high proportion ( 82%) of metaigneous rocks. The Early Cretaceous ( 109 Ma) Shipi granites were generated by partial melting of a mixed source of Paleoproterozoic metaigneous ( 92%) and metasedimentary ( 8%) rocks at a depth of 30 km plus additional ( 15%) input from coeval basaltic magma. The granites were formed in a continental arc setting induced by northwestward subduction of the Paleo

  9. Conflict Prevention and Confidence Building Measures in the South China Sea

    DTIC Science & Technology

    2013-03-01

    Sam Bateman and Ralf Emmers , eds., Security and International Politics in the South China Sea: Towards a Cooperative Management Regime (New York...reduce potential conflict and manage stability in this region. 15. SUBJECT TERMS ASEAN, ASEAN Plus Three (APT), UNCLOS, EAS, APEC, ARF, AMF...regional and international mechanisms to reduce potential conflict and manage stability in this region. Conflict

  10. Comparing the Experiences and Needs of Postsecondary International Students from China and South Korea

    ERIC Educational Resources Information Center

    Deters, Ping

    2015-01-01

    International students from China and South Korea are an increasingly important part of the international student body in many English-medium postsecondary institutions. The purpose of this qualitative study was to gain a deeper understanding of the experiences and needs of these two groups of students at a Canadian postsecondary institution. Data…

  11. Enlightenment of Development of Higher Education in South Korea to China

    ERIC Educational Resources Information Center

    Che, Zhenghong; Che, Zhengmei

    2012-01-01

    China and South Korea are two neighboring countries and are both developing countries. Furthermore, the modern and contemporary higher education of these two countries originates from the middle and late 19th Century, so there are a lot of similarities between the two countries. However, although the origination period of modern and contemporary…

  12. Analysis of South China Sea Shelf and Basin Acoustic Transmission Data

    DTIC Science & Technology

    2011-09-01

    this region ( Marburger , 2004, and Bernotavicius et al., 2010). The noise was then calculated as the sum of the distributed contributors (shipping... Marburger , J.M., “Estimation of geoacoustic properties in the South China Sea shelf using a towed source and vertical line hydrophone array,” Naval

  13. Bird community comparisons of four plantations and conservation concerns in South China.

    PubMed

    Zou, Fasheng; Yang, Qiongfang; Lin, Yongbiao; Xu, Guoliang; Greenberg, Russell

    2014-01-01

    Plantations of non-native, fast-growing trees are increasing in the tropics and subtropics, perhaps with negative consequences for the native avifauna. We studied bird diversity in 4 types of plantations in South China to determine which plantation types are especially detrimental, and compared our findings with studies in nearby natural forests to assess the magnitude of the negative impact. A total of 57 species was recorded. The mean capture rate of understory birds was 1.7 individuals 100-net-h(-1). Bird richness and capture rate were lower in plantations than in nearby natural forests. Babblers (Timaliidae), primarily forest-dependent species in South China, were particularly under-represented in plantations. Species richness, composition and bird density, particularly of understory birds, differed between plantation types. Plantations of Schima, which is native to South China, had the highest species richness according to point count data. Plantations of Acacia (non-native) supported the highest understory species richness and produced the highest capture rate of understory birds, probably because of their complex structure and high arthropod abundance. If bird diversity is to be considered, we strongly recommend that future re-afforestation projects in South China should, as far as possible, use mixed native tree species, and especially Schima, ahead of the other species. © 2013 Wiley Publishing Asia Pty Ltd, ISZS and IOZ/CAS.

  14. Distribution and Diversity of Microbial Eukaryotes in Bathypelagic Waters of the South China Sea.

    PubMed

    Xu, Dapeng; Jiao, Nianzhi; Ren, Rui; Warren, Alan

    2016-09-30

    Little is known about the biodiversity of microbial eukaryotes in the South China Sea, especially in waters at bathyal depths. Here, we employed SSU rDNA gene sequencing to reveal the diversity and community structure across depth and distance gradients in the South China Sea. Vertically, the highest alpha diversity was found at 75-m depth. The communities of microbial eukaryotes were clustered into shallow-, middle-, and deep-water groups according to the depth from which they were collected, indicating a depth-related diversity and distribution pattern. Rhizaria sequences dominated the microeukaryote community and occurred in all samples except those from less than 50-m deep, being most abundant near the sea floor where they contributed ca. 64-97% and 40-74% of the total sequences and OTUs recovered, respectively. A large portion of rhizarian OTUs has neither a nearest named neighbor nor a nearest neighbor in the GenBank database which indicated the presence of new phylotypes in the South China Sea. Given their overwhelming abundance and richness, further phylogenetic analysis of rhizarians were performed and three new genetic clusters were revealed containing sequences retrieved from the deep waters of the South China Sea. Our results shed light on the diversity and community structure of microbial eukaryotes in this not yet fully explored area.

  15. Restoration of mangrove plantations and colonisation by native species in Leizhou bay, South China

    Treesearch

    Hai Ren; Shuguang Jian; Hongfang Lu; Qianmei Zhang; Weijun Shen; Weidong Han; Zuoyun Yin; Qinfeng Guo

    2008-01-01

    To examine the natural colonisation of native mangrove species into remediated exotic mangrove stands in Leizhou Bay, South China, we compared soil physical–chemical properties, community structure and recruitments of barren mangrove areas, native mangrove species plantations, and exotic mangrove species—Sonneratia apetala Buch.Ham—between plantations and natural...

  16. Geochemical evidence for a catastrophic biotic event at the Frasnian/Famennian boundary in south China

    SciTech Connect

    Wang, Kun; Chatterton, B.D.E. ); Orth, C.J.; Attrep, M. Jr. ); Hongfei Hou ); Geldsetzer, H.H.J. )

    1991-08-01

    A strong {delta}{sup 13}C anomaly coincides with a weak Ir anomaly at the Frasnian/Famennian (F/F) boundary exposed at Xiangtian, Guangxi, south China. The maximum whole-rock Ir abundance is 0.23 ppb (0.35 ppb on a carbonate-free basis) compared with averages of 0.016 and 0.044 ppb above and below the boundary interval. The {delta}{sup 13}C in carbonate abruptly shifts from a late Frasnian level of about +1{per thousand} to {minus}2.49 {per thousand}in the boundary interval and then abruptly returns to pre-boundary levels, suggesting a temporary reduction of surface-water biomass. A widely distributed (over at least several hundred kilometers) limestone breccia unit of possible wave-deposit origin is present directly below the boundary in south China. Enrichments of Al, V, Cr, As, and U, and a dip in the Mn abundance in the boundary interval indicate that reducing conditions might have been associated with the element enrichment. However, an alternative hypothesis is that oceanic impact(s) at the F/F boundary near south China provided the excess Ir and caused the biotic crisis and the formation of breccia deposits observed in the Late Devonian South China Sea.

  17. Soil seed banks in four 22-year-old plantations in South China: implications for restoration

    Treesearch

    Jun Wang; Hai Ren; Long Yang; Danyan Li; Qinfeng. Guo

    2009-01-01

    To better understand the potentials of the soil seed banks in facilitating succession towards a morenatural forest of native tree species, we quantified the size and composition of the soil seed banks inestablished plantations in South China. The seed banks were from four typical 22-year-old plantations, i.e., legume, mixed-...

  18. Poverty Eradication: Lessons from China and South Korea in the 1950s and 1960s.

    ERIC Educational Resources Information Center

    Wignaraja, Ponna

    1996-01-01

    Traces the search for economic development alternatives that go beyond conventional neo-classical and Marxist theory and practice. Outlines case studies of social and economic transformation in South Korea and China and delineates the differences between similar attempts in Latin America and Eastern Europe. (MJP)

  19. Pattern of marine mass extinction near the Permian-Triassic boundary in South China.

    PubMed

    Jin, Y G; Wang, Y; Wang, W; Shang, Q H; Cao, C Q; Erwin, D H

    2000-07-21

    The Meishan section across the Permian-Triassic boundary in South China is the most thoroughly investigated in the world. A statistical analysis of the occurrences of 162 genera and 333 species confirms a sudden extinction event at 251.4 million years ago, coincident with a dramatic depletion of delta13C(carbonate) and an increase in microspherules.

  20. Stature, migration and human welfare in South China, 1850-1930.

    PubMed

    Ward, W Peter

    2013-12-01

    This paper offers new evidence on human stature in south China during the second half of the 19th century and early part of the 20th. It is based on the records kept by the Government of Canada of 97,123 Chinese immigrants who were required to pay an entry tax between 1885 and 1949. While the study population included both sexes and all ages from infancy to old age, it was largely male, with most ages falling between 12 and 50. The data reveal an increase of over 4cm in the adult heights of both sexes between 1850 and 1930. They also indicate an upward trend of over 5cm in the heights of adolescent males. The mean heights of male immigrants fall in the lower range of those reported in other studies of stature in south China. The rising trends contrast with a pattern of stagnation and decline reported in other recent findings but are consistent with other recent evidence of increasing economic growth, real wages, and life expectancy in south China during this period. One likely cause of improved well-being is the influence of the migrants' remittances on socioeconomic change in south China. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Study on the commercial cultivation of Gracila ria in South China

    NASA Astrophysics Data System (ADS)

    Liu, Sijian

    1987-09-01

    An important raw material for making agar-agar is the seaweed Gracilaria, which is distributed worldwide but grows mostly in the natural state in warm tropic and subtropic zones. Some countries have tried in small scale to cultivate the seaweed, but only along the coasts of South China has it been done successfully on a large commercial scale (in pond and raft culture).

  2. Preliminary study on pisionids (Annelida: Polychaeta Pisionidae) from Hainan Island coastal waters, South China Sea

    NASA Astrophysics Data System (ADS)

    Wu, Bao-Ling; Ding, Zhi-Hu; Huang, Feng-Peng

    1998-06-01

    Of the four species of Pisione Grube (1856) collected from the coastal waters of Hainan Island, the South China Sea, and described in this paper, Pisione hainanensis n. sp. is new to science; Pisione oerstedii Grube, 1857; Pisione complexa Alikunhi, 1947, and Pisione levisetosa Zhao, Westheide & Wu, 1991 are reported for the first time from this area.

  3. The spatial and temporal variability of the seasonal mean sea level cycle in the South China Sea

    NASA Astrophysics Data System (ADS)

    Muhaimin Amiruddin, Abd; Haigh, Ivan; Tsimplis, Mikis; Calafat, Francisco; Dangendorf, Soenke

    2015-04-01

    The seasonal cycle is the most energetic component of mean sea level variability and changes in either its amplitude or phase can seriously impact the risk of coastal flooding. Here, tide gauge records and satellite altimetry observations, along with steric and meteorological data are used to investigate the spatial and temporal variability of the seasonal cycle in the South China Sea (SCS) and its forcing mechanisms. The coastal annual amplitude varies significantly from region to region with values ranging from 2 cm to 24 cm, and generally peaks between July and January. The coastal semi-annual amplitude has maximum values of 7 cm, and it peaks between March and June. Along the coast, the seasonal cycle accounts on average for 60% with maximum values of up to 92% of the mean monthly sea level variability. Atmospheric pressure fluctuations explain a significant portion of the seasonal cycle with dominant annual signals in the northern SCS, the Gulf of Thailand and the north-western Philippines Sea. The wind forcing is dominant on the shelf areas of the SCS and the Gulf of Thailand where a simple barotropic model forced by local wind shows amplitudes of up to 27 cm. In the deep basin of the SCS, the Philippines Sea and the shallow Malacca Strait, the steric component is the major contributor with maximum annual amplitudes of up to 15 cm. Significant variability in the annual and semi-annual cycle is found on a year-to-year basis. The annual and semi-annual amplitudes vary by up to 63% and 45% of the maximum values, 15 cm and 11 cm, respectively. On average, stepwise regression analysis of contribution of different forcing factors accounts for 69% of the temporal variability of the annual cycle. The zonal wind and the cross-shore wind were found to exert considerable influence in the Malacca Strait and the northern SCS respectively.

  4. Sustainable management of river oases along the Tarim River in North-Western China under conditions of climate change

    NASA Astrophysics Data System (ADS)

    Rumbaur, C.; Thevs, N.; Disse, M.; Ahlheim, M.; Brieden, A.; Cyffka, B.; Doluschitz, R.; Duethmann, D.; Feike, T.; Frör, O.; Gärtner, P.; Halik, Ü.; Hill, J.; Hinnenthal, M.; Keilholz, P.; Kleinschmit, B.; Krysanova, V.; Kuba, M.; Mader, S.; Menz, C.; Othmanli, H.; Pelz, S.; Schroeder, M.; Siew, T. F.; Stender, V.; Stahr, K.; Thomas, F. M.; Welp, M.; Wortmann, M.; Zhao, X.; Chen, X.; Jiang, T.; Zhao, C.; Zhang, X.; Luo, J.; Yimit, H.; Yu, R.

    2014-10-01

    The Tarim River Basin, located in Xinjiang, NW China, is the largest endorheic river basin of China and one of the largest in whole Central Asia. Due to the extremely arid climate with an annual precipitation of less than 100 mm, the water supply along the Aksu and Tarim River solely depends on river water. This applies for anthropogenic activities (e.g. agriculture) as well as for the natural ecosystems so that both compete for water. The on-going increase of water consumption by agriculture and other human activities in this region has been enhancing the competition for water between human needs and nature. Against this background, 11 German and 6 Chinese universities and research institutes formed the consortium SuMaRiO (www.sumario.de), which aims at gaining a holistic picture of the availability of water resources in the Tarim River Basin and the impacts on anthropogenic activities and natural ecosystems caused by the water distribution within the Tarim River Basin. The discharge of the Aksu River, which is the major tributary to the Tarim, has been increasing over the past 6 decades due to enhanced glacier melt. Alone from 1989 to 2011, the area under agriculture more than doubled. Thereby, cotton became the major crop and there was a shift from small-scale farming to large-scale intensive farming. The major natural ecosystems along the Aksu and Tarim River are riparian ecosystems: Riparian (Tugai) forests, shrub vegetation, reed beds, and other grassland. Within the SuMaRiO Cluster the focus was laid on the Tugai forests, with Populus euphratica as dominant tree, because the most productive and species-rich natural ecosystems can be found among those forests. On sites with groundwater distance of less than 7.5 m the annual increments correlated with river runoffs of the previous year. But, the further downstream along the Tarim River, the more the natural river dynamics ceased, which impacts on the recruitment of

  5. Community structure of archaea from deep-sea sediments of the South China Sea.

    PubMed

    Wang, Peng; Li, Tao; Hu, Anyi; Wei, Yuli; Guo, Wenting; Jiao, Nianzhi; Zhang, Chuanlun

    2010-11-01

    Using the archaeal 16S rRNA gene, we determined the community structures of archaea of subseafloor sediments (∼9-11 m below seafloor) from two geographically distant cores (MD05-2896, south, water depth 1,657 m; MD05-2902, north, water depth 3,697 m) in the South China Sea. Euryarchaeota accounted for 61.4% of total archaeal clone libraries at MD05-2896 and 56.2% at MD05-2902. At both locations, the Euryarchaeota-related sequences were dominated by Marine Benthic Group D, Terrestrial Miscellaneous Eryarchaeotal Group, and South African GoldMine Euryarchaeotal Group; the Crenarchaeota-related sequences were dominated by Marine Benthic Group B, Marine Group I, pSL12, and C3. The community structure showed no significant difference with depth at each location, suggesting the lack of stratification of archaeal populations in the deep-sea marine sediments in the South China Sea. On the other hand, the community structure is significantly different between the two sites, which may be related to geographical difference in the South China Sea.

  6. Paliurus Fruits from the Oligocene of South China and Their Phytogeographic Implications

    PubMed Central

    Dong, Jun-Ling; Sun, Bai-Nian; Ma, Fu-Jun; Wang, Qiu-Jun; Jin, Pei-Hong; Wang, Wen-Jia; Deng, Peng; Yang, Yi; Li, Xiao-Jing

    2015-01-01

    Paliurus favonii Unger is recognized and described based on fruits from the Oligocene Ningming flora of Guangxi, South China. Characteristics of the present specimens include circular winged fruits that are 10.0–11.5 mm in diameter with a central endocarp at 3.0 to 4.0 mm in diameter. The specimens fall into the morphological range of the fossil species P. favonii, which has been observed in other Cenozoic sites in the Northern Hemisphere. The present discovery represents the lowest latitude distribution of P. favonii in the world, and we are presenting the first P. favonii fossil described with detailed cuticular characteristics from China. Further, this finding demonstrates that the genus existed in the Oligocene Ningming region, South China, and provides new information for understanding the fossil history. The dispersal mode for winged fossils demonstrates that wind dispersal is well-represented in the Oligocene Ningming flora. PMID:26536607

  7. Paliurus Fruits from the Oligocene of South China and Their Phytogeographic Implications.

    PubMed

    Dong, Jun-Ling; Sun, Bai-Nian; Ma, Fu-Jun; Wang, Qiu-Jun; Jin, Pei-Hong; Wang, Wen-Jia; Deng, Peng; Yang, Yi; Li, Xiao-Jing

    2015-01-01

    Paliurus favonii Unger is recognized and described based on fruits from the Oligocene Ningming flora of Guangxi, South China. Characteristics of the present specimens include circular winged fruits that are 10.0-11.5 mm in diameter with a central endocarp at 3.0 to 4.0 mm in diameter. The specimens fall into the morphological range of the fossil species P. favonii, which has been observed in other Cenozoic sites in the Northern Hemisphere. The present discovery represents the lowest latitude distribution of P. favonii in the world, and we are presenting the first P. favonii fossil described with detailed cuticular characteristics from China. Further, this finding demonstrates that the genus existed in the Oligocene Ningming region, South China, and provides new information for understanding the fossil history. The dispersal mode for winged fossils demonstrates that wind dispersal is well-represented in the Oligocene Ningming flora.

  8. Cancer Incidence and Mortality Survey in Wuwei, Gansu Province, Northwestern China from 2003 to 2012: A Retrospective Population-based Study

    PubMed Central

    Li, Cheng-Yun; Ye, Yan-Cheng; Liang, Ge-Yu; Zhang, Wen-Hua; Zhang, Zhi-Yi; Liu, Xiao-Qin; Liang, Ying; Xu, Fen-Lan; Li, Jing; Xiang, Ji-Lian

    2016-01-01

    Background: Population-based cancer registry collects the data on cancer incidence and mortality deaths from covered population to describe and survey the epidemics in certain areas. The aim of this study was to estimate the cancer incidence and mortality in Wuwei, Gansu province, Northwestern China from 2003 to 2012. The goal is to better understand cancer distribution and long-term development of cancer prevention and treatment in Wuwei. Methods: Data were collected from the Wuwei Cancer Registry between 2003 and 2012. In this registry, data from 46 cancer report centers were included in this analysis. Incidence/mortality rates, age-specific incidence/mortality rates, age-standardized incidence/mortality rates, and cumulative incidence/mortality rates were calculated. Totally, 9,836,740 person-years (5,110,342 for males and 4,726,398 for females) had been monitored over this time period. The gender ratio of male/female was 1.08:1. The number of new cancer cases and related deaths was 24,705 and 17,287 from 2003 to 2012, respectively. Results: The proportion of morphological verification was 74.43%. The incidence of cases identified through death certification only was 1.21%, and the mortality to incidence ratio was 0.70. The average crude incidence was 251.15/100,000 persons (310.61 and 186.87 for males and females per 100,000 persons, respectively). The age-standardized rates by Chinese standard population (ASR-China) and by world standard population (ASR-world) were 207.76 and 245.42 per 100,000 persons, respectively. The crude cancer mortality was 175.74/100,000 persons (228.34 and 118.86 for males and females per 100,000 persons). ASR for China and the world was 149.57 and 175.13/100,000 persons, respectively. The most common cancers and leading causes of cancer-related deaths in Wuwei were as follows: cancers of stomach, esophagus, liver, lung, colorectum, breast, cervix, lymphoma, blood (leukemia), brain, and central nervous system. In Wuwei, during 2003

  9. Temporal stability and variability of soil-water content in a gravel-mulched field in northwestern China

    NASA Astrophysics Data System (ADS)

    Zhao, Wenju; Cui, Zhen; Zhang, Jiyi; Jin, Jian

    2017-09-01

    Characterizing the spatiotemporal variability of soil-water content (SWC) is of paramount importance in many scientific fields and operational applications. We present a case study of the temporal stability and variability of SWC in a gravel-mulched field, a form of mulching that has been widely used by farmers on the loessial area of China for over 300 years, using Spearman correlation coefficients, frequency distributions and an index of temporal stability. SWC was measured weekly from May to August 2013 in the 0-10, 10-20, 20-30 and 30-50 cm layers. SWC was more variable in the surface soil, due to several environmental factors, and the variability gradually decreased with depth. A large sample size was needed for estimating the mean SWC of the field under dry conditions. High Spearman correlation coefficients between the SWCs measured on different sampling campaigns indicated a high temporal stability. The stability of the SWC spatial patterns over time and along the soil profile allowed us to identify a location representative of the field-mean SWC, with high coefficients of determination ranging between 0.8564 and 0.9325. The large-scale monitoring of SWC from few observations is thus feasible, which will aid the management of soil moisture in gravel-mulched fields in arid regions.

  10. Paleomagnetic age of the Tangxian planation surface, northwestern Zhongtiao Shan of the Shanxi Graben System, North China

    NASA Astrophysics Data System (ADS)

    Xiong, Jianguo; Li, Youli; Zhong, Yuezhi; Si, Supei; Lei, Jinghao; Xin, Weilin; Hu, Xiu; Yao, Yifan

    2017-04-01

    A numerical formation age for the Tangxian planation surface (TXPS) in North China is still controversial. The TXPS, beveled across paleoarchean basement rocks, is overlain by late Cenozoic conglomerate, aeolian red clay, and loess. The magnetostratigraphy of two late Cenozoic deposition sections is established, and two other sections are recorded and measured in this work. The magnetostratigraphy indicates six normal magnetozones (N1 to N6) and six reverse magnetozones (R1 to R6). These magnetozones are correlated to chron C1n through C2An.1r, indicating that the TXPS was formed at 3.12-3.03 Ma. The characteristics of the Zhongtiao Shan tectonic uplift and its relationship with the Tibetan Plateau and Ordos Block are discussed in terms of tectonic uplift. The TXPS formation and accumulation of the late Cenozoic sediments are mainly controlled by tectonic activities. The formation and uplift of the TXPS with a lag in the Shanxi Graben System is consistent with the activities of the Tibetan Plateau and Ordos Block, implying that the NE extension of the Tibetan Plateau epeirogenic uplift advances successively.

  11. Estimating the Evaporation from Irrigation Canals in Northwestern China Using the Double-Deck Surface Air Layer Model

    NASA Astrophysics Data System (ADS)

    Wang, Weizhen

    2017-04-01

    The evaporation from irrigation canals was estimated by the aerodynamic method based on the double-deck surface air layer model (called "DSAL model" for short hereafter). The DSAL model describes the surface air layer over a canal as a composite air layer with two sublayers, the lower sublayer and the upper sublayer. The lower sublayer is a few tens of centimetres thick and formed by the flowing water, in which there is no advection; the upper sublayer is over the lower sublayer and formed by the surface wind. The results were compared to those obtained by the heat balance method; field experiments were conducted in the middle reaches of the Heihe River in north western China. Results showed that cumulative evaporation instances estimated by the DSAL model were equal in order of magnitude to those by the heat balance method on observed days during the daytime (0700˜1900BST). We infer from these experimental results that the evaporation loss in transport in this region is of the order of one percent at most.

  12. Hysteresis Effect of Runoff of the Heihe River on Vegetation Cover in the Ejina Oasis in Northwestern China

    NASA Astrophysics Data System (ADS)

    JIN, Xiaomei; HU, Guangcheng; LI, Wenmei

    The relationship between vegetation growth and groundwater in arid areas is one of the most actively researching topics in ecohydrology. On account of little precipitation, the oasis is the only form of sustenance for living and economic development, for the local people in the arid areas of Northwest China. During recent years, with the increase of water consumption in the middle stream area of the Heihe river basin, the incoming water has decreased gradually and the area of the Ejina oasis in the downstream area has decreased continuously. It has caused lake drying, land desertification, and eco-environmental degradation. The vegetation growth of the oasis has a close relationship with the water resources. Therefore, research on the quantitative relationship between the runoff and the vegetation growth has significance in improving the eco-environment, and balancing the contradiction of water consumption and reasonable allocation of the water resources in the Heihe river basin. Combined with remote sensing data and runoff of the Heihe river, the quantitative relationship between the vegetation growth of the Ejina oasis and the runoff of the Heihe river has been established from the regional scale in this study. The result indicates that the growth of oasis vegetation depends on the runoff of the Heihe river and the groundwater. The time lag of the impact of the runoff of the river on the vegetation cover of the Ejina oasis is one year, and the groundwater links the vegetation cover and the runoff by this hysteresis effect.

  13. Structural analysis and deformation characteristics of the Yingba metamorphic core complex, northwestern margin of the North China craton, NE Asia

    NASA Astrophysics Data System (ADS)

    Yin, Congyuan; Zhang, Bo; Han, Bao-Fu; Zhang, Jinjiang; Wang, Yang; Ai, Sheng

    2017-01-01

    The presence of the Yingba (Yinggete-Bagemaode) metamorphic core complex (MCC) is confirmed near the Sino-Mongolian border in China. We report its structural evolution and the rheological features of ductile shear zones within this complex. Three deformations (Ds, Dm, and Db) since the Late Jurassic are identified. Ds is characterized by ductile structures that resulted from early NW-oriented, low-angle, extensional ductile shearing. Dm is associated with partial melting and magmatic diapirism, which accelerated the formation of the dome-like geometry of the Yingba MCC. Synchronously with or slightly subsequently to Ds and Dm, the Yingba MCC was subjected to brittle, extensional faulting (Db), which was accompanied by the exhumation of the lower crust and the formation of supracrustal basins. The ductile shearing (Ds) developed under greenschist-to amphibolite-facies metamorphic conditions (400-650 °C), as indicated by microstructures in quartz and feldspar, quartz [c] axis fabrics, and two-feldspar geothermometry. The mean kinematic vorticity estimates of 48-62% show a pure shear-preferred flow during Ds. The Yingba MCC provides an excellent sample that recorded an intermediate to high temperature shearing, which also implies the widely extensional regime in northeastern Asia at that time.

  14. Size-related change in Nitraria sphaerocarpa patches shifts the shrub-annual interaction in an arid desert, northwestern China

    NASA Astrophysics Data System (ADS)

    Zhang, Gefei; Yang, Qiyue; Wang, Xiaofen; Zhao, Wenzhi

    2015-11-01

    In arid and semi-arid ecosystems, the effect of shrubs on their understory plants has been frequently reported. Many previous studies have shown that both facilitation and competition act simultaneously, and their balance changes in response to spatial or temporal variations in environmental stresses. Yet, we know little about how the interaction varies between shrubs and their understory plants in vegetation patches with different characteristics. Here, an empirical investigation was conducted in Hexi desert region of northwest China, to evaluate how the net effect of Nitraria sphaerocarpa shrubs on the herbaceous species varies across different sizes of N. sphaerocarpa patches. Our study showed that herbaceous species perform better on small shrub patches. But the magnitude of this facilitative effect decreased with increasing patch size, and finally shifted to interference in large patches. The results indicated that these negative shifts in plant interactions were not clearly related to 'shrub-island effect' in terms of nutrient accumulation or soil properties improvement, but may be explained by the variation in other abiotic factors, such as soil moisture and available light. Changes in root distribution and canopy structure of N. sphaerocarpa shrubs with the increase of patch size seem to also partly explain the variation in shrub-understory species interactions, as a result of increased above- and below-ground niche overlaps.

  15. Dynamics of the Water Circulations in the Southern South China Sea and Its Seasonal Transports

    PubMed Central

    Ooi, See Hai; Samah, Azizan Abu; Akbari, Abolghasem

    2016-01-01

    A three-dimensional Regional Ocean Modeling System is used to study the seasonal water circulations and transports of the Southern South China Sea. The simulated seasonal water circulations and estimated transports show consistency with observations, e.g., satellite altimeter data set and re-analysis data of the Simple Ocean Data Assimilation. It is found that the seasonal water circulations are mainly driven by the monsoonal wind stress and influenced by the water outflow/inflow and associated currents of the entire South China Sea. The intrusion of the strong current along the East Coast of Peninsular Malaysia and the eddies at different depths in all seasons are due to the conservation of the potential vorticity as the depth increases. Results show that the water circulation patterns in the northern part of the East Coast of Peninsular Malaysia are generally dominated by the geostrophic currents while those in the southern areas are due solely to the wind stress because of negligible Coriolis force there. This study clearly shows that individual surface freshwater flux (evaporation minus precipitation) controls the sea salinity balance in the Southern South China Sea thermohaline circulations. Analysis of climatological data from a high resolution Regional Ocean Modeling System reveals that the complex bathymetry is important not only for water exchange through the Southern South China Sea but also in regulating various transports across the main passages in the Southern South China Sea, namely the Sunda Shelf and the Strait of Malacca. Apart from the above, in comparision with the dynamics of the Sunda Shelf, the Strait of Malacca reflects an equally significant role in the annual transports into the Andaman Sea. PMID:27410682

  16. Reviews and new metallogenic models of mineral deposits in South China: An introduction

    NASA Astrophysics Data System (ADS)

    Hu, Rui-Zhong; Chen, Wei Terry; Xu, De-Ru; Zhou, Mei-Fu

    2017-04-01

    In South China, the Yangtze and Cathaysia blocks were welded together along the Jiangnan Fold Belt during Neoproterozoic time (∼830 Ma). Large-scale mineralization in these two blocks occurred from Proterozoic to Cenozoic, making the region one of the most important polymetallic metallogenic provinces in the world. Of particular importance are world-class deposits of iron-oxide copper gold (IOCG), sediment-hosted Mn-P-Al-(Ni, Mo, PGE), syenite-carbonatite-related REE, felsic intrusion-related Sn-W-Mo-Cu-Fe-Pb-Zn, mafic intrusion-related V-Ti-Fe and Cu-Ni-PGE and low-temperature hydrothermal Pb, Zn, Au, and Sb (Fig. 1). In addition, the Ta-Nb, Hg, As, Tl and U deposits in South China are among the world largest of these kinds. Because of these deposits, South China has been a focus of researches for many years. Publications before 2005 were mostly restricted in Chinese. In the past decade, some case studies on some world-class deposits in South China are available in international journals. These recent studies have advanced our understanding of their mode of formation. However, some important issues regarding the timing, tectonic setting and mechanisms of metal concentration still remain poorly understood. This special issue brings together some of the latest information on these topics, including major review papers on specific types of mineralization and several papers dealing with some specific deposits in the region. We anticipate that this issue will generate more interests in the studies of mineral deposits in South China. In this introduction, we outline the tectonic framework and associated deposits.

  17. Dynamics of the Water Circulations in the Southern South China Sea and Its Seasonal Transports.

    PubMed

    Daryabor, Farshid; Ooi, See Hai; Samah, Azizan Abu; Akbari, Abolghasem

    2016-01-01

    A three-dimensional Regional Ocean Modeling System is used to study the seasonal water circulations and transports of the Southern South China Sea. The simulated seasonal water circulations and estimated transports show consistency with observations, e.g., satellite altimeter data set and re-analysis data of the Simple Ocean Data Assimilation. It is found that the seasonal water circulations are mainly driven by the monsoonal wind stress and influenced by the water outflow/inflow and associated currents of the entire South China Sea. The intrusion of the strong current along the East Coast of Peninsular Malaysia and the eddies at different depths in all seasons are due to the conservation of the potential vorticity as the depth increases. Results show that the water circulation patterns in the northern part of the East Coast of Peninsular Malaysia are generally dominated by the geostrophic currents while those in the southern areas are due solely to the wind stress because of negligible Coriolis force there. This study clearly shows that individual surface freshwater flux (evaporation minus precipitation) controls the sea salinity balance in the Southern South China Sea thermohaline circulations. Analysis of climatological data from a high resolution Regional Ocean Modeling System reveals that the complex bathymetry is important not only for water exchange through the Southern South China Sea but also in regulating various transports across the main passages in the Southern South China Sea, namely the Sunda Shelf and the Strait of Malacca. Apart from the above, in comparision with the dynamics of the Sunda Shelf, the Strait of Malacca reflects an equally significant role in the annual transports into the Andaman Sea.

  18. International Ocean Discovery Program Expedition 349 and Multidisciplinary Research in the South China Sea

    NASA Astrophysics Data System (ADS)

    Lin, J.; Li, C. F.; Wang, P.; Koppers, A. A. P.; Dadd, K. A.; Kulhanek, D. K.

    2014-12-01

    The South China Sea (SCS) is one of the largest low-latitude marginal seas in the world, serving as a natural laboratory for studying the linkages between complex tectonic, volcanic, and oceanic processes. The last several years have witnessed significant progress in investigation of the SCS through comprehensive research programs using multidisciplinary approaches and enhanced international collaboration. In January-March 2014, International Ocean Discovery Program (IODP) Expedition 349 drilled and cored five sites in the SCS, with three sites located near the relict spreading center in the East and Southwest Subbasins and two sites near the transition zone between the oceanic and continental crust (Expedition 349 Scientists, 2014). The expedition successfully obtained the first basaltic rock samples of the SCS relict spreading center, discovered large and frequent deep-sea turbidity events, and sampled multiple seamount volcaniclastic layers. The Expedition 349 shipboard and shorebased research involves the participation and strong collaboration of scientists from the international community including scientists from countries and regions surrounding the SCS. Meanwhile, major progress in studying the SCS processes has also been made through comprehensive multidisciplinary programs, for example, the "South China Sea Deep" initiative (Wang, 2012). This presentation will highlight the recent multidisciplinary research initiatives in investigation of the SCS and the important role of international collaboration. Expedition 349 Scientists, 2014. South China Sea tectonics: Opening of the South China Sea and its implications for southeast Asian tectonics, climates, and deep mantle processes since the late Mesozoic. International Ocean Discovery Program Preliminary Report, 349. http://dx.doi.org/10.14379/iodp.pr.349.2014. Wang, P., 2012. Tracing the life history of a marginal sea—on "The South China Sea Deep" research program. Chinese Science Bulletin, 57(24), 3093

  19. Detrital zircon provenance of the Paleogene syn-rift sediments in the northern South China Sea

    NASA Astrophysics Data System (ADS)

    Shao, Lei; Cao, Licheng; Pang, Xiong; Jiang, Tao; Qiao, Peijun; Zhao, Meng

    2016-02-01

    The early rift sedimentation history of the South China Sea is still not well understood due to restricted borehole coverage of the Paleogene strata and lack of reliable stratigraphic dating. We use detrital zircon U-Pb geochronology to explore the source-to-sink characteristics of syn-rift sequences in the northern South China Sea. The results reveal significant intrabasinal provenances in addition to the well-perceived terrigenous supply from the north. The Dongsha Uplift is considered to account for the dominance of the Early Cretaceous zircons in the Eocene samples. The Lower Oligocene sediments in the Qiongdongnan Basin could have been sourced from Hainan Island and local uplifts, but their distinction cannot be confirmed by the U-Pb age spectra. Contemporary sediments in the northern Pearl River Mouth Basin were most likely transported from southeastern South China with well-rounded zircon grains showing U-Pb age similarity to those from the northeastern tributaries of the Pearl River. By contrast, intrabasinal sources from the west and east are suggested to have contributed the infill of the southern part of the Pearl River Mouth Basin based on generally euhedral zircon shapes. These sedimentary source patterns appear to change very little in the Oligocene northern South China Sea. However, the newly detected Neoproterozoic zircons in the Upper Oligocene sediments from borehole L21 tend to indicate a southern source. The episodic and diachronic nature of rifting and erosion processes in the early South China Sea is the cause of complex patterns in the Paleogene provenance history.

  20. Spatial-temporal characteristics of the "cumulative effect" of torrential rain over South China

    NASA Astrophysics Data System (ADS)

    Chu, Qucheng; Wang, Qiguang; Qiao, Shaobo; Feng, Guolin

    2017-02-01

    To expand torrential rain, which is a meso- and microscale weather process, to a meso- and long-scale weather process, in this paper, we choose South China as a sample region and propose the conception of the "Cumulative Effect" of torrential rain (CETR) by using daily precipitation observational data from 740 stations. Through a statistical analysis of the observations, three indexes—continuous time ( L d), control area ( A r), and precipitation contribution rate ( Q s)—are used to define the CETR and indicate the torrential rain processes. The relationships between the CETR and simultaneous total precipitation over South China are analyzed in the pre-flooding and latter flooding seasons. This analysis shows that on both interannual and interdecadal scales, the three indexes are highly correlated with simultaneous total precipitation over South China in the pre-flooding season and latter flooding season. Moreover, an empirical orthogonal function (EOF) analysis is performed to classify the spatial distribution of the CETR. In both the pre-flooding season and the latter flooding season, the four major spatial models of torrential rain are similar to those of total precipitation over South China. With regard to the amount of precipitation caused by the CETR, the latter flooding season is affected more significantly than the pre-flooding season. Regarding the geographical distribution of precipitation, the opposite result occurs. In conclusion, in both the pre-flooding season and the latter flooding season, the CETR influences and even determines the amount and distribution of precipitation over South China.

  1. Atmospheric nitrogen deposition to the northwestern Pacific: seasonal variation and source attribution

    NASA Astrophysics Data System (ADS)

    Zhao, Yuanhong; Zhang, Lin; Pan, Yuepeng; Wang, Yuesi; Paulot, Fabien; Henze, Daven

    2016-04-01

    Rapid Asian industrialization has lead to increased atmospheric nitrogen deposition downwind threatening the marine environment. We present an analysis of the sources and processes controlling atmospheric nitrogen deposition to the northwestern Pacific, using the GEOS-Chem global chemistry model and its adjoint model at 1/2°× 2/3° horizontal resolution over the East Asia and its adjacent oceans. We focus our analyses on the marginal seas: the Yellow Sea and the South China Sea. Asian nitrogen emissions in the model are 28.6 Tg N a-1 as NH3 and 15.7 Tg N a-1 as NOx. China has the largest sources with 12.8 Tg N a-1 as NH3 and 7.9 Tg N a-1 as NOx; the much higher NH3 emissions reflect its intensive agricultural activities. We improve the seasonality of Asian NH3 emissions; emissions are a factor of 3 higher in summer than winter. The model simulation for 2008-2010 is evaluated with NH3 and NO2 column observations from satellite instruments, and wet deposition flux measurements from surface monitoring sites. Simulated atmospheric nitrogen deposition to the northwestern Pacific ranges 0.8-20 kg N ha-1 a-1, decreasing rapidly downwind the Asian continent. Deposition fluxes average 11.9 kg N ha-1 a-1 (5.0 as reduced nitrogen NHx and 6.9 as oxidized nitrogen NOy) to the Yellow Sea, and 5.6 kg N ha-1 a-1 (2.5 as NHx and 3.1 as NOy) to the South China Sea. Nitrogen sources over the ocean (ship NOx and oceanic NH3) have little contribution to deposition over the Yellow Sea, about 7% over the South China Sea, and become important (greater than 30%) further downwind. We find that the seasonality of nitrogen deposition to the northwestern Pacific is determined by variations in meteorology largely controlled by the East Asian Monsoon and in nitrogen emissions. The model adjoint further points out that nitrogen deposition to the Yellow Sea originates from sources over China (92% contribution) and the Korean peninsula (7%), and by sectors from fertilizer use (24%), power plants

  2. Atmospheric nitrogen deposition to the northwestern Pacific: seasonal variation and source attribution

    NASA Astrophysics Data System (ADS)

    Zhao, Y.; Zhang, L.; Pan, Y.; Wang, Y.; Paulot, F.; Henze, D. K.

    2015-09-01

    Rapid Asian industrialization has led to increased downwind atmospheric nitrogen deposition threatening the marine environment. We present an analysis of the sources and processes controlling atmospheric nitrogen deposition to the northwestern Pacific, using the GEOS-Chem global chemistry model and its adjoint model at 1/2° × 2/3° horizontal resolution over East Asia and its adjacent oceans. We focus our analyses on the marginal seas: the Yellow Sea and the South China Sea. Asian nitrogen emissions in the model are 28.6 Tg N a-1 as NH3 and 15.7 Tg N a-1 as NOx. China has the largest sources with 12.8 Tg N a-1 as NH3 and 7.9 Tg N a-1 as NOx; the high-NH3 emissions reflect its intensive agricultural activities. We find Asian NH3 emissions are a factor of 3 higher in summer than winter. The model simulation for 2008-2010 is evaluated with NH3 and NO2 column observations from satellite instruments, and wet deposition flux measurements from surface monitoring sites. Simulated atmospheric nitrogen deposition to the northwestern Pacific ranges 0.8-20 kg N ha-1 a-1, decreasing rapidly downwind of the Asian continent. Deposition fluxes average 11.9 kg N ha-1 a-1 (5.0 as reduced nitrogen NHx and 6.9 as oxidized nitrogen NOy) to the Yellow Sea, and 5.6 kg N ha-1 a-1 (2.5 as NHx and 3.1 as NOy) to the South China Sea. Nitrogen sources over the ocean (ship NOx and oceanic NH3) have little contribution to deposition over the Yellow Sea, about 7 % over the South China Sea, and become important (greater than 30 %) further downwind. We find that the seasonality of nitrogen deposition to the northwestern Pacific is determined by variations in meteorology largely controlled by the East Asian monsoon and in nitrogen emissions. The model adjoint further estimates that nitrogen deposition to the Yellow Sea originates from sources over China (92 % contribution) and the Korean peninsula (7 %), and by sectors from fertilizer use (24 %), power plants (22 %), and transportation (18

  3. Evidence for North-South Long Range Transport of Pollutants Across the South China Sea During the Winter Monsoon

    NASA Astrophysics Data System (ADS)

    Sturges, W. T.

    2015-12-01

    A new atmospheric observing station has been established on the east coast of Peninsular Malaysia on the southern seaboard of the South China Sea. During a first intensive campaign in January-February 2014, evidence was observed for substantial elevations in a wide range of greenhouse gases and ozone depleting substances, including CO­2 and CH4 and industrially-derived halocarbons such as HCFCs, HFCs and chlorinated solvents, during "cold surge" conditions at the end of the winter monsoon. Carbon monoxide and ozone were also elevated at such times. Air mass footprints indicated that flow during these events was from eastern China and the Indochina Peninsular. Satellite fire counts indicated that substantial biomass burning was taking place, notably in Vietnam and Cambodia, at this time. As the air mass footprints moved east towards the Western Pacific, mixing ratios of all such gases declined to typical northern hemispheric background conditions. These findings are of note both as a clear indication of the long-range transport of a mixture of biomass burning products and industrial emissions over thousands of kilometres across the South China Sea, and also because such transported pollutants may be subject to rapid vertical transport to the upper troposphere and lower stratosphere by tropical deep convection.

  4. Mesozoic non-marine petroleum source rocks determined by palynomorphs in the Tarim Basin, Xinjiang, northwestern China

    USGS Publications Warehouse

    Jiang, D.-X.; Wang, Y.-D.; Robbins, E.I.; Wei, J.; Tian, N.

    2008-01-01

    The Tarim Basin in Northwest China hosts petroleum reservoirs of Cambrian, Ordovician, Carboniferous, Triassic, Jurassic, Cretaceous and Tertiary ages. The sedimentary thickness in the basin reaches about 15 km and with an area of 560000 km2, the basin is expected to contain giant oil and gas fields. It is therefore important to determine the ages and depositional environments of the petroleum source rocks. For prospective evaluation and exploration of petroleum, palynological investigations were carried out on 38 crude oil samples collected from 22 petroleum reservoirs in the Tarim Basin and on additionally 56 potential source rock samples from the same basin. In total, 173 species of spores and pollen referred to 80 genera, and 27 species of algae and fungi referred to 16 genera were identified from the non-marine Mesozoic sources. By correlating the palynormorph assemblages in the crude oil samples with those in the potential source rocks, the Triassic and Jurassic petroleum source rocks were identified. Furthermore, the palynofloras in the petroleum provide evidence for interpretation of the depositional environments of the petroleum source rocks. The affinity of the miospores indicates that the petroleum source rocks were formed in swamps in brackish to lacustrine depositional environments under warm and humid climatic conditions. The palynomorphs in the crude oils provide further information about passage and route of petroleum migration, which is significant for interpreting petroleum migration mechanisms. Additionally, the thermal alternation index (TAI) based on miospores indicates that the Triassic and Jurassic deposits in the Tarim Basin are mature petroleum source rocks. ?? Cambridge University Press 2008.

  5. Integrating the SD-CLUE-S and InVEST models into assessment of oasis carbon storage in northwestern China

    PubMed Central

    Huang, Jiejun

    2017-01-01

    Spatio-temporal integrated assessment of land-use change impacts on carbon storage services is a new and important research field in land science and landscape ecology. The objective of this paper is to use an integrated SD-CLUE-S and InVEST model to simulate and predict land-use changes impacts during 2000–2018 on carbon storage at pixel and regional scales in the Zhangye oasis, Northwest China. The SD-CLUE-S model was used to simulate land-use change, and three land-use scenarios (current trend, moderate protection, and strict protection) were defined in collaboration with oasis socioeconomic development and ecological environment conservation by local government. The InVEST model was then used to simulate land-use change impacts on carbon storage at different scales in the oasis. The results showed that: (1) the effects of built-up land expansion were especially notable, with a rapid decrease in cropland during 2009–2018; (2) the strict protection scenario saved the largest amount of carbon storage for the oasis compared with the current trend and moderate protection scenarios. The scientific value of this study has been to show that the proposed modeling method can be used to reflect different land-use patterns and their effects on ecosystem services at multiple scales in the oasis. Furthermore, this research can be used to help government managers encourage stakeholders to contribute funds and strategies to maintain oasis landscape patterns and ecological processes by implementing local plans for potential conservation projects. PMID:28231328

  6. Terrestrial Permian - Triassic boundary sections in South China

    NASA Astrophysics Data System (ADS)

    Bercovici, Antoine; Vajda, Vivi

    2016-08-01

    The Permian-Triassic boundary interval in China comprises a significant record of faunal and floral changes during this important extinction event. Here we discuss the details of palynomorph preservation at the classical Western Guizhou and Eastern Yunnan sections in an effort to expand the stratigraphy and paleontology from these earlier studies.

  7. Maternal Education and Micro-Geographic Disparities in Nutritional Status among School-Aged Children in Rural Northwestern China

    PubMed Central

    Wang, Cuili; Kane, Robert L.; Xu, Dongjuan; Li, Lingui; Guan, Weihua; Li, Hui; Meng, Qingyue

    2013-01-01

    Objectives Prior evidence suggests geographic disparities in the effect of maternal education on child nutritional status between countries, between regions and between urban and rural areas. We postulated its effect would also vary by micro-geographic locations (indicated by mountain areas, plain areas and the edge areas) in a Chinese minority area. Methods A cross-sectional study was conducted with a multistage random sample of 1474 school children aged 5-12 years in Guyuan, China. Child nutritional status was measured by height-for-age z scores (HAZ). Linear mixed models were used to examine its association with place of residence and maternal education. Results Micro-geographic disparities in child nutritional status and the level of socioeconomic composition were found. Children living in mountain areas had poorer nutritional status, even after adjusting for demographic (plain versus mountain, β = 0.16, P = 0.033; edge versus mountain, β = 0.29, P = 0.002) and socioeconomic factors (plain versus mountain, β = 0.12, P = 0.137; edge versus mountain, β = 0.25, P = 0.009). The disparities significantly widened with increasing years of mothers’ schooling (maternal education*plain versus mountain: β = 0.06, P = 0.007; maternal education*edge versus mountain: β = 0.07, P = 0.005). Moreover, the association between maternal education and child nutrition was negative (β = -0.03, P = 0.056) in mountain areas but positive in plain areas (β = 0.02, P = 0.094) or in the edge areas (β = 0.04, P = 0.055). Conclusions Micro-geographic disparities in child nutritional status increase with increasing level of maternal education and the effect of maternal education varies by micro-geographic locations, which exacerbates child health inequity. Educating rural girls alone is not sufficient; improving unfavorable conditions in mountain areas might make such investments more effective in promoting

  8. The oleaginous Botryococcus from the Triassic Yanchang Formation in Ordos Basin, Northwestern China: Morphology and its paleoenvironmental significance

    NASA Astrophysics Data System (ADS)

    Ji, Li-ming; Yan, Kui; Meng, Fan-wei; Zhao, Min

    2010-05-01

    fluctuation was narrow during the Mid-Later Triassic. The ecological type of the palynological flora discovered from the Ch 7 to Ch 8 in Xifeng area is similar to that from the Fuxian Lake, with abundant Botryococcus in the Yungui Plateau of China. These findings imply that the Ordos Basin was in a lower-latitude area of temperate to subtropical climate during the Middle and Late Triassic.

  9. Maternal education and micro-geographic disparities in nutritional status among school-aged children in rural northwestern China.

    PubMed

    Wang, Cuili; Kane, Robert L; Xu, Dongjuan; Li, Lingui; Guan, Weihua; Li, Hui; Meng, Qingyue

    2013-01-01

    Prior evidence suggests geographic disparities in the effect of maternal education on child nutritional status between countries, between regions and between urban and rural areas. We postulated its effect would also vary by micro-geographic locations (indicated by mountain areas, plain areas and the edge areas) in a Chinese minority area. A cross-sectional study was conducted with a multistage random sample of 1474 school children aged 5-12 years in Guyuan, China. Child nutritional status was measured by height-for-age z scores (HAZ). Linear mixed models were used to examine its association with place of residence and maternal education. Micro-geographic disparities in child nutritional status and the level of socioeconomic composition were found. Children living in mountain areas had poorer nutritional status, even after adjusting for demographic (plain versus mountain, β = 0.16, P = 0.033; edge versus mountain, β = 0.29, P = 0.002) and socioeconomic factors (plain versus mountain, β = 0.12, P = 0.137; edge versus mountain, β = 0.25, P = 0.009). The disparities significantly widened with increasing years of mothers' schooling (maternal education*plain versus mountain: β = 0.06, P = 0.007; maternal education*edge versus mountain: β = 0.07, P = 0.005). Moreover, the association between maternal education and child nutrition was negative (β = -0.03, P = 0.056) in mountain areas but positive in plain areas (β = 0.02, P = 0.094) or in the edge areas (β = 0.04, P = 0.055). Micro-geographic disparities in child nutritional status increase with increasing level of maternal education and the effect of maternal education varies by micro-geographic locations, which exacerbates child health inequity. Educating rural girls alone is not sufficient; improving unfavorable conditions in mountain areas might make such investments more effective in promoting child health. Nutrition programs targeting to the least educated groups in plain and in edge areas would be

  10. Spatial pattern of soil moisture and its temporal stability within profiles on a loessial slope in northwestern China

    NASA Astrophysics Data System (ADS)

    Jia, Yu-Hua; Shao, Ming-An; Jia, Xiao-Xu

    2013-07-01

    Temporal stability of spatial distributions of soil moisture are usually observed after repeated surveys of soil moisture across an area. To understand how temporal stability of soil moisture varied with soil depth under the combined influences of vegetation and local topography, we collected soil moisture data at intervals of 10 cm within 1-m profiles on a loessial slope in China in four plots (61 m × 5 m) under different types of vegetation (Korshinsk peashrub, KOP; purple alfalfa, ALF; natural fallow, NAF; millet, MIL). Measurements of soil water content were made by neutron probes on 15 occasions between 2010 and 2012. Soil moisture distributions in both the vertical and horizontal dimensions were investigated to describe its spatial pattern and to lay the groundwork for better understanding its temporal stability characteristics. The results indicated that: (1) soil moisture presented different vertical but similar horizontal trends in the four plots, with significant correlations of soil moisture occurring primarily among adjacent soil layers irrespective of vegetation types, mostly in soil profiles under KOP and ALF and less frequently in soil profiles under NAF and MIL; (2) based on Spearman rank correlation coefficients, with increasing depth temporal stability generally increased under KOP and MIL, but first increased and then decreased under ALF, and increased after the first three measurements under NAF; (3) based on the relative difference technique, points with extreme moisture tended to remain representative at more depths than did points with average moisture and their time stability increased with increasing soil depth; and (4) the correlation between MRD (mean relative differences) and the wetness index weakened with soil depth. The relationship between SDRD (the standard deviation of MRD) and the wetness index varied nonlinearly with soil depth. Vegetation type, soil depth and the wetness index, in descending order of influence, had significant

  11. Contrasting Distributions of Bacterial Branched Tetraethers along a Soil-River-Lake Transect in the Arid Region of Northwestern China

    NASA Astrophysics Data System (ADS)

    Lu, J.

    2016-12-01

    Understanding the transport of branched glycerol dialkyl glycerol tetraethers (brGDGTs) along the soil-river-lake transect is of vital importance, which helps discriminate the autochthonous from allochthonous contribution of brGDGTs in lake and river environment and favors the application of brGDGT-based proxies in paleo-reconstruction. We collected the sediment samples from the Qinghai Lake, the largest saline lake in China, as well as the river sediments and catchment soils, to examine the difference in the distribution of 5- vs. 6-methyl brGDGTs along the soil-river-lake transect. The brGDGT distributions were found to show a large variation along the transect, which can be reflected by the MBT'-derived indices and IR (isomer ratio) indices. There is a considerable difference in brGDGT distributions between soil and the river sediment. The inflowing rivers likely receive terrestrial brGDGT input to a variable degree. BrGDGTs in the Buha river are primarily of autochthonous origin whereas other ephemeral streams, like the Heima river, exhibit a similar brGDGT distribution to the surrounding soils, reflecting that these compounds are likely derived from soils. A higher quantity of 6-methyl brGDGTs and brGDGT-Ia was observed in the lake than in the river sediments, pointing to a preferential degradation of 5-methyl brGDGTs and/or an increase of in situ production of 6-methyl brGDGTs in the lake. Besides the difference in brGDGT distributions caused by the transportation and in situ production along the transect, we also identified the difference caused by several driving factors in different environments. In arid and alkaline soils, both CBT' and IR indices have strong correlations with soil pH even within the narrow pH range. However, we find a clear relationship of CBT with water salinity in Buha river. The difference in soil and river leads to a complicated interpretation for the CBT (CBT') index. In the lake, the MBT' (specially represented by MBT'5ME and MBT'6

  12. Mercury concentrations in forest soils and stream waters in northeast and south China.

    PubMed

    Luo, Yao; Duan, Lei; Wang, Long; Xu, Guangyi; Wang, Shuxiao; Hao, Jiming

    2014-10-15

    Atmospheric deposition of mercury (Hg) is generally higher in China than in North America and Europe. Transport and methylation of Hg deposited in forest ecosystems may cause health risks to humans. We collected water samples from 117 small streams, and soil samples from 25 sites in forested areas in northeast and south China during 2011-2013 to investigate the spatial distribution of Hg. Results showed that Hg concentration in surface soil (0-5 cm in depth) was generally higher in south China (97.8 ± 36.0 μg/kg) than that in the northeast (44.0 ± 14.1 μg/kg). In contrast, the Hg concentration in stream water was higher in northeast China (17.2 ± 11.0 ng/L) than that in the south (6.2 ± 6.4 ng/L). Hg concentrations in surface soil were positively correlated with Hg concentrations in the overlying litter Oe/Oa horizon (r(2)=0.84). Hg concentrations in stream water were positively correlated to DOC (dissolved organic carbon) concentrations (r(2)=0.43) and to the Hg concentration in the litter Oe/Oa horizon (r(2)=0.69). Because the litter Oe/Oa horizon represents Hg accumulated by foliage, the positive correlations indicate that atmospheric Hg deposition was an important factor affecting Hg concentrations in soils and stream water.

  13. The Field Operations and Early Results of the South China Sea Monsoon Experiment (SCSMEX)

    NASA Technical Reports Server (NTRS)

    Lau, K. M.; Ding, Yihui; Wang, Jough-Tai; Johnson, Richard; Keenan, Tom; Cifelli, Robert; Gerlach, John; Thiele, Otto; Rickenbach, Tom; Tsay, Si-Chee

    1999-01-01

    The South China Sea Monsoon Experiment (SCSMEX) is an international field experiment with the objective to better understand the key physical processes for the onset and evolution of the Asian summer monsoon in relation to fluctuation of the regional hydrologic cycle over Southeast Asian, southern East Asia, aiming at improving monsoon prediction. In this article, we present a description of the major meteorological observation platforms during the Intensive Observing Periods (IOP) of SCSMEX. We also provide highlights of early results and discussions of the role of SCSMEX in providing valuable in-situ data for calibration of satellite rainfall estimate from the Tropical Rainfall Measuring Mission (TRMM). Preliminary results indicate that there are distinctive stages in the onset of the South China Sea monsoon including possibly strong influences from extratropical systems as well as from convection over the Indian Ocean and the Bay of Bengal. There are some tantalizing evidence of complex interactions between the supercloud cluster development over the Indian Ocean, advancing southwest monsoon flow over the South China Sea, midlatitude disturbances and the western Pacific subtropical high, possibly contributing to the disastrous flood over Yangtze River Basin in China during June 1998.

  14. Rift-related Devonian sedimentation and basin development in South China

    NASA Astrophysics Data System (ADS)

    Xun, Zhao; Allen, Mark B.; Whitham, Andrew G.; Price, Simon P.

    During Devonian times South China lay to the north of the Palaeo-Tethyan ocean, the boundary being a passive continental margin. A shallow sea covered the southern parts of the continent while northern areas, forming the Huanan Landmass, were emergent. At the beginning of the Devonian most of South China was above sea level. Subsequent transgression from the south gave rise to an irregular coastline with the development of many fault-controlled gulfs. Further transgression led to the development of an epicontinental sea with reefs forming along the margins of the submerged gulfs and black shales deposited within them. By Emsian time a widespread carbonate platform was established, while anoxic deposition continued in the troughs. The marine transgression peaked in the Frasnian Stage. During Famennian time widespread regression occurred and much of South China became once more emergent. Peneplanation of the Huanan Landmass led to the partial infilling of many of the older fault-bounded depressions. Throughout the Devonian the local distribution of sediments was strongly controlled by NE-SW trending transtensional faults that bounded NW-SE trending normal faults. These structures continued to influence sedimentation in the Late Palaeozoic, the Mesozoic and possibly the Tertiary in the offshore Beibu Gulf Basin.

  15. Perceived Environmental Pollution and Its Impact on Health in China, Japan, and South Korea

    PubMed Central

    2017-01-01

    Objectives Environmental pollution is a significant global issue. Both objective (scientifically measured) environmental pollution and perceived levels of pollution are important predictors of self-reported health. The purpose of this study was to compare the associations between perceived environmental pollution and health in China, Japan, and South Korea. Methods Data were obtained from the East Asian Social Survey and the Cross-National Survey Data Sets: Health and Society in East Asia, 2010 (n=7938; China, n=3866; Japan, n=2496; South Korea, n=1576). Results South Koreans perceived environmental pollution to be the most severe, while Japanese participants perceived environmental pollution to be the least severe. Although the Japanese did not perceive environmental pollution to be very severe, their self-rated physical health was significantly related to perceived environmental pollution, while the analogous relationships were not significant for the Chinese or Korean participants. Better mental health was related to lower levels of perceived air pollution in China, as well as lower levels of perceived all types of pollution in Japan and lower levels of perceived noise pollution in South Korea. Conclusions Physical and mental health and individual socio-demographic characteristics were associated with levels of perceived environmental pollution, but with different patterns among these three countries. PMID:28605887

  16. Perceived Environmental Pollution and Its Impact on Health in China, Japan, and South Korea.

    PubMed

    Kamimura, Akiko; Armenta, Bianca; Nourian, Maziar; Assasnik, Nushean; Nourian, Kimiya; Chernenko, Alla

    2017-01-01

    Environment