Ecological indicators showing the succession of macrofauna communities in Sonneratia apetala artificial mangrove wetlands on Qi’ao Island at Zhuhai, South China     

TANG Yijie  FANG Zhanqiang  ZHANG Zaiwang  ZHONG Yanting  CHEN Kang  LIU Benhan  FAN Junjie  XIONG Tiantian  LU Xiaosheng 《海洋学报(英文版)》2014,33(8):62-72

The Sonneratia apetala artificial mangroves in the intertidal zone of Da Wei Bay at Qi’ao Island of Zhu-hai, South China were chosen as the macrofauna succession plots while bare tidal flats of the same size were established as control plots in surrounding interference-free areas. Conventional change indicators of community structure, such as biomass and biodiversity, and indicators, such as exergy and specific exergy, which reflect the information change of overall communities, were used to analyze the succession of macro-fauna communities inS. apetala artificial mangroves. The similarities and differences in variation tendency of the different ecological indicators and their reflected ecological principles were compared. The results showed that from D-1 to D-1275 after plantingS. apetala, the biomass of the macrofauna communities first increased, which was then followed by an increase in the network relationship between the macrofauna communities （analysis of the Pielou evenness index and Shannon-Wiener diversity index）. The system in-formation （specific exergy） increased the slowest. Between D-1460 and D-2370 after plantingS. apetala, there was a decrease in biomass, network structure, and system information in the succession plots. After the decrease in the system information （the specific exergy）, there was a decline in the network relationships （Pielou evenness index and Shannon-Wiener diversity index）. Biomass was the last indicator to decrease. The similarities and differences among the different ecological indicators varied during the succession pro-cess, which reflected the relativity and differences among the indicators. This study suggested that, although the species diversity index can be an effective indicator of two types of changes （network structure and system information）, it was quite clear that species diversity measurement was not suitable for expressing the changes in biomass during the succession process. While exergy and specific exergy can provide useful information  相似文献   

Assessment of future climate change over East Asia due to the RCP scenarios downscaled by GRIMs-RMP   总被引：1，自引：1，他引：0  

Ji-Woo Lee  Song-You Hong  Eun-Chul Chang  Myoung-Seok Suh  Hyun-Suk Kang 《Climate Dynamics》2014,42(3-4):733-747

This study assesses future climate change over East Asia using the Global/Regional Integrated Model system—Regional Model Program (RMP). The RMP is forced by two types of future climate scenarios produced by the Hadley Center Global Environmental Model version 2 (HG2); the representative concentration pathways (RCP) 4.5 and 8.5 scenarios for the intergovernmental panel on climate change fifth assessment report (AR5). Analyses for the current (1980–2005) climate are performed to evaluate the RMP’s ability to reproduce precipitation and temperature. Two different future (2006–2050) simulations are compared with the current climatology to investigate the climatic change over East Asia centered in Korea. The RMP satisfactorily reproduces the observed seasonal mean and variation of precipitation and temperature. The spatial distribution of the simulated large-scale features and precipitation by the RMP is generally less reflective of current climatic conditions than that is given by the HG2, but their inter-annual variations in East Asia are better captured by the RMP. Furthermore, the RMP shows higher reproducibility of climate extremes including excessive heat wave and precipitation events over South Korea. In the future, strong warming is distinctly coupled with intensified monsoonal precipitation over East Asia. In particular, extreme weather conditions are increased and intensified over South Korea as follows: (1) The frequency of heat wave events with temperature greater than 30 °C is projected to increase by 131 and 111 % in the RCP 8.5 and 4.5 downscaling, relative to the current climate. (2) The RCP 8.5 downscaling shows the frequency and variability of heavy rainfall to increase by 24 and 31.5 %, respectively, while the statistics given by the RCP 4.5 downscaling are similar to those of the current climate.  相似文献   

Drought variability at the northern fringe of the Asian summer monsoon region over the past millennia   总被引：3，自引：0，他引：3  

Bao Yang  Shuyuan Kang  Fredrik Charpentier Ljungqvist  Minhui He  Yan Zhao  Chun Qin 《Climate Dynamics》2014,43(3-4):845-859

The northern fringe of the Asian summer monsoon region (NASM) in China refers to the most northwestern extent of the Asian summer monsoon. Understanding the characteristics and underlying mechanisms of drought variability at long and short time-scales in the NASM region is of great importance, because present and future water shortages are of great concern. Here, we used newly developed and existing tree-ring, historical documentary and instrumental data available for the region to identify spatial and temporal patterns, and possible mechanisms of drought variability, over the past two millennia. We found that drought variations were roughly consistent in the western (the Qilian Mountains and Hexi Corridor) and eastern (the Great Bend of the Yellow River, referred to as GBYR) parts of the NASM on decadal to centennial timescales. We also identified the spatial extent of typical multi-decadal GBYR drought events based on historical dryness/wetness data and the Monsoon Asia Drought Atlas. It was found that the two periods of drought, in AD 1625–1644 and 1975–1999, exhibited similar patterns: specifically, a wet west and a dry east in the NASM. Spatial characteristics of wetness and dryness were also broadly similar over these two periods, such that when drought occurred in the Karakoram Mountains, western Tianshan Mountains, the Pamirs, Mongolia, most of East Asia, the eastern Himalayas and Southeast Asia, a wet climate dominated in most parts of the Indian subcontinent. We suggest that the warm temperature anomalies in the tropical Pacific might have been mainly responsible for the recent 1975–1999 drought. Possible causes of the drought of 1625–1644 were the combined effects of the weakened Asian summer monsoon and an associated southward shift of the Pacific Intertropical Convergence Zone. These changes occurred due to a combination of Tibetan Plateau cooling together with more general Northern Hemisphere cooling, rather than being solely due to changes in the sea surface temperature of the tropical Pacific. Our results provide a benchmark for comparing and validating paleo-simulations from general circulation model of the variability of the Asian summer monsoon at decadal to centennial timescales.  相似文献   

Present and projected degree days in China from observation,reanalysis and simulations   总被引：1，自引：0，他引：1  

Qinglong You  Klaus Fraedrich  Frank Sielmann  Jinzhong Min  Shichang Kang  Zhenming Ji  Xiuhua Zhu  Guoyu Ren 《Climate Dynamics》2014,43(5-6):1449-1462

Degree days are usually defined as the accumulated daily mean temperature varying with the base temperature, and are one of the most important indicators of climate changes. In this study, the present-day and projected changes of four degree days indices from daily mean surface air temperature output simulated by Max Planck Institute, Earth Systems Model of low resolution (MPI-ESM-LR) model are evaluated with the high resolution gridded-observation dataset and two modern reanalyses in China. During 1979–2005, the heating degree days (HDD) and the numbers of HDD (NHDD) have decreased for observation, reanalyses (ERA-Interim and NCEP/NCAR) and model simulations (historical and decadal experiments), consistent with the increasing cooling degree days (CDD) and the numbers of CDD (NCDD). These changes reflect the general warming in China during the past decades. In most cases, ERA-Interim is closer to observation than NCEP/NCAR and model simulations. There are discrepancies between observation, reanalyses and model simulations in the spatial patterns and regional means. The decadal hindcast/forecast simulation performance of MPI-ESM-LR produce warmer than the observed mean temperature in China during the entire period, and the hindcasts forecast a trend lower than the observed. Under different representative concentration pathway (RCP) emissions scenarios, HDD and NHDD show significant decreases, and CDD and NCDD consistently increase during 2006–2100 under RCP8.5, RCP4.5 and RCP2.6, especially before the mid-21 century. More pronounced changes occur under RCP8.5, which is associated with a high rate of radiative forcing. The 20th century runs reflect the sensitivity to the initial conditions, and the uncertainties in terms of the inter-ensemble are small, whereas the long-term trend is well represented with no differences among ensembles.  相似文献   

Taxila LBM: a parallel,modular lattice Boltzmann framework for simulating pore-scale flow in porous media     

Ethan T. Coon  Mark L. Porter  Qinjun Kang 《Computational Geosciences》2014,18(1):17-27

The lattice Boltzmann method is a popular tool for pore-scale simulation of flow. This is likely due to the ease of including complex geometries such as porous media and representing multiphase and multifluid flows. Many advancements, including multiple relaxation times, increased isotropy, and others have improved the accuracy and physical fidelity of the method. Additionally, the lattice Bolzmann method is computationally very efficient, thanks to the explicit nature of the algorithm and relatively large amount of local work. The combination of many algorithmic options and efficiency means that a software framework enabling the usage and comparison of these advancements on computers from laptops to large clusters has much to offer. In this paper, we introduce Taxila LBM, an open-source software framework for lattice Boltzmann simulations. We discuss the design of the framework and lay out the features available, including both methods in the literature and a few new enhancements which generalize methods to complex geometries. We discuss the trade-off of accuracy and performance in various methods, noting how the Taxila LBM makes it easy to perform these comparisons for real problems. And finally, we demonstrate a few common applications in pore-scale simulation, including the characterization of permeability of a Berea sandstone and analysis of multifluid flow in heterogenous micromodels.  相似文献   

陕北煤矿区地质环境保护与恢复治理措施——以神府矿区郭家湾煤矿为例     

李永红  何意平  康金栓  张新宇  李辉  滕宏泉  丁佳 《中国煤炭地质》2014,(4):41-45,57

郭家湾煤矿地处神府矿区新民采区西北部,为生态环境脆弱区。井田七层煤三个煤组开采后引发地面塌陷、含水层疏干、土地结构变化等地质环境问题,严重制约了地方经济的发展。为了煤炭资源可持续发展,研究陕北煤矿区地质环境保护与恢复治理措施,以1∶10000野外详细调查为依据,首先进行现状评估,然后针对矿山工程建设可能遭受、加剧、引发的矿山地质环境问题进行预测评估,最后提出了以移民搬迁、回填裂缝、生态恢复、建立矿山地质环境监测体系等为主的防治措施,让煤矿开采与矿山地质环境问题恢复治理并行。旨为陕北地区乃至全国煤矿,在保护地质环境中开发利用矿产资源提供依据和示范。  相似文献   

淮南煤田潘三煤矿4-2煤中矿物对岩浆侵入的响应     

李秀芝  ;陈健  ;康彧  ;刘桂建 《中国煤炭地质》2014,(7):12-14

以淮南煤田潘三煤矿4-2煤层中的岩浆岩、天然焦和煤样品为研究对象,利用X射线衍射仪和X射线荧光光谱仪测试其矿物组成和主量元素含量,研究地下岩浆侵入对煤中矿物成分的影响。结果表明:煤变质成天然焦后,其总的矿物含量增多,并伴随着后生矿物如微斜长石和镁绿泥石的出现。天然焦中后生矿物的组成元素可能来源于岩浆或热液中的主量元素如Si、Al、Na、K、Fe和Mg。  相似文献   

GIS-based lake sediment budget estimation taking into consideration land use change in an urbanizing catchment area     

S. M. Kim  T. I. Jang  M. S. Kang  S. J. Im  S. W. Park 《Environmental Earth Sciences》2014,71(5):2155-2165

The objective of this study was to assess the lake sediment budget of land use changes using the Universal Soil Loss Equation (USLE), sediment delivery ratio (SDR), and trap efficiency (TE). The geographic information system was combined with the USLE to estimate the soil erosion of the Lake Asan watershed. Spatial data for each of the USLE factors were obtained from the land use, soil, and 1/25,000 scale digital contour maps. Landsat-5 TM images were selected for analyzing soil erosion changes due to land use changes. The sediment yield to Lake Asan was estimated using the SDR and TE. The estimated sediment budget was compared with observed data from the Lake Asan watershed between 1974 and 2003. The total estimated annual mean sediment budgets from Lake Asan in 1986, 1992, and 2000 were 0.267, 0.301, and 0.339 × 10⁶ ton, respectively, with an average of 0.302 × 10⁶ ton. The average measured sediment budget was 3.15 × 10⁶ ton year^?1. The average estimated value shows reasonable agreement with the observed sediment balance. The average estimated and measured sediment budgets contain uncertainties due to both the methods and the approach used by the observers. The simulated results indicated that soil erosion in the Lake Asan watershed increased at a rate of approximately 2 % per year from 1986 to 2000 due to land use change. This study may be useful for managers to identify reservoir rehabilitation management methods for stable irrigation water supply.  相似文献   

Hydrologic modelling of the effect of snowmelt and temperature on a mountainous watershed   总被引：2，自引：0，他引：2  

Kwangmin Kang  Joo Hyoung Lee 《Journal of Earth System Science》2014,123(4):705-713

Snowmelt-runoff modelling in a mountainous basin is perceived as difficult due to the complexity of simulation. Theoretically, the snowmelt process should be influenced by temperature changes. It is still controversial as how to incorporate the temperature changes into the snowmelt-runoff model in a mountainous basin. This paper presents the results of a study in the North Fork American River basin where the snowmelt-runoff mechanism is modelled by relating the temperature changes to the elevation band in the basin. In this study, a distributed hydrologic model is used to explore the orographic effects on the snowmelt-runoff using the snowfall-snowmelt routine in Soil and Water Assessment Tool (SWAT). Three parameters, namely maximum snowmelt factor, minimum snowmelt factor, and snowpack temperature lag were analysed during the simulation. The model was validated using streamflow data from October 1, 1991 to September 30, 1994 with and without considering the elevation band. The result of this study suggests that the snowmelt-runoff model associated with the elevation band better represents the snowmelt-runoff mechanism in terms of Nash–Sutcliffe coefficient (E _NS ), R ², and Root Mean Square Error (RMSE).  相似文献   

云南普朗超大型斑岩铜矿床含矿斑岩成因及其成矿意义   总被引：5，自引：1，他引：4  

曹康  许继峰  陈建林  黄肖潇  任江波 《矿床地质》2014,33(2):307-322

普朗超大型斑岩铜矿床位于三江特提斯构造域义敦弧南部的中甸弧内,形成于晚三叠世甘孜-理塘大洋板片向西俯冲的消减带上。与成矿作用密切相关的石英闪长岩和石英二长岩具有相似的化学组成,w（SiO₂）>61%,w（Al₂O₃）为11.28%~19.12%,w（MgO）为1.98%~4.04%,Na₂O/K₂O比值介于0.3~2.4（平均0.8）;富集大离子亲石元素（Rb、Sr、Ba）而亏损高场强元素（Nb、Ta、Zr）,具有较高的Sr/Y（27~63）和La/Yb（14~31）比值,较明显的负Eu异常,在Y-Sr/Y和Yb-La/Yb图解中,部分样品落入埃达克岩范围内,另一些样品则落入正常弧钙碱性岩石范围。普朗含矿斑岩部分样品的埃达克岩地球化学属性可能与以下地质-地球化学过程有关：晚三叠世甘孜-理塘大洋板片向西俯冲时发生脱挥发分作用导致上覆地幔楔遭受流体交代,被流体交代的地幔楔随后发生部分熔融形成正常拉斑玄武质-钙碱性岩浆,这种钙碱性岩浆在岩浆房中或侵位过程中发生角闪石、斜长石和磷灰石等矿物的分离结晶作用形成埃达克质石英闪长岩或石英二长岩。普朗含矿斑岩中黑云母和角闪石斑晶的广泛发育表明原始岩浆是富水的,这种富水环境促进角闪石的大量结晶而抑制部分斜长石的结晶,导致残余岩浆的Sr/Y比值增加,从而使部分岩石样品具有埃达克岩的地球化学特征。这种富水的原始岩浆有利于后期岩浆热液体系的形成及铜等金属元素向流体相中分配转移,并最终形成普朗超大型斑岩铜矿床。  相似文献