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  • 2011 Volume 31 Issue 2
    Published: 20 February 2011
      
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  • Environmental Characteristics and Changes of Coastal Ocean as Land-ocean Transitional Zone of China
    WANG Ying, JI Xiao-mei
    2011, 31(2): 129-135. https://doi.org/10.13249/j.cnki.sgs.2011.02.129
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    Coastal ocean is the transitional zone between the land and the ocean.It extends from coastal Zone to the outer edge of the continental shelves, then continues to continental slopes and continental rises.Approximately matching the region that has been alternately flooded and exposed during the sea level fluctuations of the late Quaternary period, and has covered relatively complete zones with land and ocean interactions.It is an independent environment system which is different from the land and the deep ocean, and is closely related to human living activities.Since ’The United Nations Law of Sea Convention’took effect in 1994, coastal ocean has become a hotspot of the earth sciences domain because of the requirement of maritime sovereignty and resources development.Located on the interaction zone of Asia and the Pacific Ocean, Chinese coast is of various types.The coastal ocean environment and processes are unique due to the river-sea interaction and the influence of human activities.Evolution of China coast reflects the influence of geology, rivers, climate, typhoons, waves, tides, shelf currents, and sea level changes.While tectonics control the broad scale appearance of the coast (either embayed bedrock in emergent regions or plain coast in subsiding regions), rivers dominate the supply of sediment to the sea and help control erosional/accretionary trends.The influence of global change and human activities on river drainage areas also appears in coastal ocean area and affects marine environment remarkably due to the transfixion action of the rivers.The coastal classification was applied to dividing the coast of China into four major sectors.The impact of rivers, waves and tides on coastal processes in each of these sectors varies widely, ranging from river-dominated in the Bohai Sea sector, to wave-dominated in the southern Guangdong/Guangxi sector.The characteristics and problems in the coastal development are analyzed taking the plain coast as an example.The eastern coast has been a living and multiplying place of China for a long time.However, the characteristics of the environmental system of the land-ocean transitional zone have not been well understood.The contemporary large scale development induced a series of problems.The negative effects such as seawater pollution caused the decline of precipitation and freshwater quality, with frequent red tide disasters, and endanger human life.Therefore, more attention should be paid to the study of the environmental characteristics of the land-ocean transitional zone.It is very important to understand the variability of the environmental factors and to standardize the development activities.Historical and realistic examples show that people should investigate the environmental features of the study area, explore the mechanism of its dynamical processes, illustrate the trend of its development, and design projects within the threshold limits to avoid human-induced disasters.
  • Progress on Spatial Variation of Methanogens and Their Influencing Factors in Natural Wetlands
    LIU De-yan, DING Wei-xin
    2011, 31(2): 136-142. https://doi.org/10.13249/j.cnki.sgs.2011.02.136
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    The spatial variability of predominant methanogenic archaea, main pathways of methane production and their influencing factors in natural wetlands are reviewed.Temperature could not only directly alter the community structure and function of methanogenic archaea, but also might affect the supply of substrates for methanogens, which in turn indirectly regulate the function of methanogenic archaea.The underlying mechanism of temperature on methane production in natural wetlands is not to be understood clearly.Acetoclastic methanogens generally live in wetlands vegetated with vascular plants, while reduction of H2/CO2 or hydrogenotrophic methanogensis is the main pathway for methane production in peatland where few vascular plants is present.The presence of free acetic acid in wetlands might reduce the activities of acetoclastic methanogens when pH is <4.7, but hydrogenotrophic methanogens and other microorganisms might have a special mechanism to compensate for decoupling by acetic acid.Meanwhile, we also give hints on future studies from natural wetlands in China.
  • Comprehensive Risk Assessment Method for Groundwater Environment System Based on Stochastic Simulation and Triangular Fuzzy Numbers
    JIN Ju-liang, LIU Li, WANG Ming-wu, LI Ru-zhong, ZHOU Yu-liang
    2011, 31(2): 143-147. https://doi.org/10.13249/j.cnki.sgs.2011.02.143
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    Influenced by the changes in natural conditions and human activities, groundwater vulnerability assessment, focusing on the vulnerability evaluation inherent to the hydrogeology, has reached a new phase of integrated risk assessment by taking into account the pollution caused by human activities, its negative effects on water environment, as well as the index risk rank and risk importance of groundwater environment.To resolve the problems of the impreciseness, complex implementation and the real number, resulted from the existing approaches to quantitatively describe the risk grade and importance of groundwater environment system, a aggregative risk assessment method for groundwater environment system was established, using Stochastic Simulation and Triangular Fuzzy Numbers (ARA-SSTFN).Based on an overall consideration of the hydrogeology and human activity factors, the proposed model transforms the operations between triangular fuzzy numbers and its functions into the conventional operations of real numbers by using stochastic simulation methods to generate triangular numbers.The result shows that the ARA-SSTFN, expressed by the confidence intervals, provides more reliable information on the evaluation results than the current conventional approaches, and can reflect the actual conditions of the comprehensive risk assessment for groundwater environment system affected by various uncertain factors comprehensively.It is also indicated that the ARA-SSTFN has a clear concept, a simple implementation, and it is sufficiently general to be applicable to the comprehensive risk assessment in various resources and environment systems (e.g., water resources, water environments, and water disasters) as a result of comprehensive effects of many uncertain factors, such as randomness, fuzziness and inexact data.
  • Exposure Assessment of Rainstorm Waterlogging on Buildings in Central Urban Area of Shanghai Based on Scenario Simulation
    QUAN Rui-song, LIU Min, ZHANG Li-jia, LU Min, WANG Jing-jing, NIU Hai-yan, XU Shi-yuan
    2011, 31(2): 148-152. https://doi.org/10.13249/j.cnki.sgs.2011.02.148
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    Due to rapid urban development and land use and land cover changes, the waterlogging induced by torrential rain or typhoon in urban areas has been a global hotspot and a potential risk affecting the safety of urban buildings and interior property.This study applied a simplified urban waterlogging model to simulating the inundated water depth in central urban area of Shanghai under different scenarios.And each building was ranked according to its degree of exposure indicated by the inundation depth.Finally, the exposure of buildings to rainstorm waterlogging in central urban area of Shanghai under different scenarios was analyzed and evaluated.The results showed that the warehousing and the old-style residence are the most vulnerable building types when exposed to waterlogging disasters.On the whole, Yangpu District, Putuo District and Xuhui District are the important regions for the government to carry out safety defense, Changning District and Hongkou District have medium exposure rank, and the waterlogging brings little effects in Huangpu District, Jing’an District, Luwan District and Zhabei District.These results will provide references for the local government to improve waterlogging risk management.
  • Modification of Palmer Drought Severity Index of Regional Drought
    ZHANG Wei-dong, SHI Lin
    2011, 31(2): 153-158. https://doi.org/10.13249/j.cnki.sgs.2011.02.153
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    The Palmer Drought Severity Model is an important model to estimate the severity of drought.After being introduced into China in the 20th century, a series of corrections have been made by An Shunqing, etc.This method is used to the operation by the data from single site.We averaged the data of single site and then integrated them.We constructed the model with seven typical sites of Liaohe basin in Liaoning.And we used the data gained from other 23 stations from the Haihe-Luanhe River basin, the Huaihe River basin, the Huanghe River basin and the Changjiang River basin as basic data and relevant data to obtain the weighting coefficient.And we use the Synthetical Water Equilibrium Model replace the former one.After the corroboration, the result accords with the fact, and be meaningful to the research of regional drought.
  • Remote Sensing Retrieval of Suspended Particulate Matter Concentrations of Surface Waters near Radial Sand Ridges Area in the South Yellow Sea
    FAN Hui, HUANG Hai-jun
    2011, 31(2): 159-165. https://doi.org/10.13249/j.cnki.sgs.2011.02.159
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    Two experimental above-water radiance measurement campaigns were conducted during spring and autumn of 2003 in the coastal waters near radial sand ridges area in the South Yellow Sea, with a co-incident water sampling for each measurement.In this paper, response patterns of spectral signature to concentrations of total suspended particulate matter (TSM) and suspended sediment (SSC) in the surface waters were investigated based upon in situ remote sensing reflectance and water sample.The best statistical algorithms, including one-band, two-band or band ratio and three-band algorithms, for TSM and SSC were presented based upon the simulated spectral signature at the wavebands of the major satellite ocean color sensors.The results show that the best performance wavebands of these algorithms in spring were entirely different from those in autumn.This shows that defining TSM and SSC empirical retrieval algorithms suitable for all seasons is to only select the second best performance wavebands.
  • Riverine Organic Carbon Content and Significance of Carbon Isotopic Composition in the Xijiang River, China
    WEI Xiu-guo, LI Ning-li, SHEN Cheng-de, GUO Zhi-xing
    2011, 31(2): 166-171. https://doi.org/10.13249/j.cnki.sgs.2011.02.166
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    This paper presents data of a 8-year time series of particulate organic carbon (POC) and dissolved organic carbon (DOC), and isotopic composition (Δ14C, δ13C) of suspended sediment at Makou section of the Xijiang River.We also discuss the sources of suspended sediment, using natural 14C method.The results of organic carbon concentration show temporal variation.Among them, POC content ranges from 0.13 mg/L to 4.98 mg/L with the average value of 1.35 mg/L and DOC content range from 0.98 mg/L to 4.17 mg/L with the average value of 1.86 mg/L.The content of DOC is slightly higher than that of POC in most cases, indicating that POC produced by mechanical erosion is not dominant, while DOC resulting from decomposition of organic matter was dominant in the Xijiang River.The DOC/POC ratio is 1.34, higher than that of the Changjiang (Yangtze) River and the Huanghe (Yellow) Rivers.In recent years, suspended POCδ13C ranges from -21.3‰ to -26.1‰, showing drift phenomenon with the time, and indicating the overall improvement of the ecological environment in the Xijiang River basin.The suspended sediment Δ14C values ranges from -132‰ to -425‰, whose variation were closely related to soil erosion produced by precipitation during the sampling period.The deeper soil erosion contributes more to "negative" suspended sediment POCΔ14C value and aged organic carbon; while the shallow soil erosion contributes more to "positive" suspended sediment POCΔ14C value and young organic carbon.
  • Rational Ecological Groundwater Level of Populus euphraticawith Different Diameter in Lower Reaches of Tarim River
    YE Mao, XU Hai-liang, GONG Jun-Jun, AN Hong-yan
    2011, 31(2): 172-177. https://doi.org/10.13249/j.cnki.sgs.2011.02.172
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    Based on the methods of Dendrohydrology, this paper analyzed the sensitivity change and trend in the ring width growth of the Populus euphratica with different truck diameter grades under different groundwater depths in the lower reaches of Tarim River.The results show that, with the increase of groundwater depth, the ring width of the Populus euphratica with different trunk diameter grades also has a deceasing trend.The regression equations of groundwater depth and the ring width of the Populus euphratica with different trunk diameter grades is:y=-0.0135 x3+0.2882 x2-2.011 x+6.1356 (truck diameter of 4-10 cm);y=0.008 x3-0.093 x2-0.264 x+5.276 (trunk diameter of 10-30 cm) and y=0.0556 x3-1.2008 x2+8.1323 x-5.547 (trunk diameter of 30-50 cm).Those relationships are significant (p<0.01).With the increase of groundwater depth, the Sk of the ring width change of the Populus euphratica decreases firstly and then increases.When the Sk with trunk diameters of 4-10 cm, 10-30 cm and 30-50 cm are up to maximum, the responding groundwater depth is 3.3 m, 7.4 m and 7.9 m, respectively.We can draw a conclusion that the three groundwater depths are regarded as rational groundwater with water stress of Populus euphratica with different truck diameter.
  • Evolution of Physical and Chemical Characteristics of Loess with Different Landforms in Slope Field under Sand Cover
    ZHANG Li-ping, WANG Xiao-yun, ZHANG He-si
    2011, 31(2): 178-183. https://doi.org/10.13249/j.cnki.sgs.2011.02.178
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    The study aimed at the impacts of the different landforms on the soil physical composition, soil moisture content and soil fertility of the slope loess field under sand cover.The series of samples were collected at section planes and vertical soil layers, in Yinmaquan watershed located on the boundary between Shenmu County and Dongsheng City, where the slope field had the representations.The soil texture, gravimetric soil moisture content and organic matter content of the samples were measured.Based on the analysis of the data, conclusions were obtained:1) The soil texture and physical clay granule content were indices to indicate the desertification degree and evolvement trend.The study area demonstrated a drier and coarser trend towards northwest.2) There were different evolution laws of soil moisture content with different landform positions.It increased vertically from the top to upside of hilly slope, but decreased from the downside to foot.Whatever position the landform had, there was a similar balanced depth existed for the soil to evaporate, infiltrate, leak and hold water.3) The physical clay granule content had closely relationship with the soil fertility and moisture content.The section planes with higher physical clay granule contents had richer soil fertility and more moisture content.4) Effects of the combination of water, fertilizer and organic matter became more effective from the top to the foot of slope field, indicating that landform always had significant impacts on the series of evolution processes such as soil mellowing processes, soil degradation, soil erosion and soil desertification.Furthermore, the results also highlighted the evolution of soil texture with the landforms and the vertical soil layers, and could indicate the process of soil desertification and materials sources.
  • Natural Vegetation Pattern over Northeast China in Late 17th Century
    ZHANG Xue-zhen, WANG Wei-chyung, FANG Xiu-qi, YE Yu, LI Bei-bei
    2011, 31(2): 184-189. https://doi.org/10.13249/j.cnki.sgs.2011.02.184
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    We collected multiple historical documents including gazettes, government archives, traveling notes and so on, from which the primary natural vegetation information is complied.Using the information, the primary natural vegetation pattern prior to significant agriculture (i.e.late 17th century) was reconstructed.The results show that woodland and grassland were dominant vegetation over the Northeast China in the late 17th century.Woodland occupied the mountain areas, of which the northern of the Da Higgan Mountains was occupied by boreal forest, southern of the Changbai Mountains were covered by temperate broadleaf deciduous forest and the other mountains were occupied by mixed forest.Grassland covered Northeast China Plain and Inner Mongolia Plateau.The boundaries between woodland and grassland were nearly consistent with topography contour lines.Besides, swamp had small area and nearly covered the whole Sanjiang Plain.The macro pattern of historical nature vegetation was similar with the potential natural vegetation; however, the boundaries of woodland and grassland from the two datasets were evidently different and there was no swamp in potential natural vegetation dataset.
  • Soil Respiration Variant and Its Effecting Factors at Different Land Use in Arid Land
    ZHOU Hong-hua, LI Wei-hong, YANG Yu-hui, CAO Zhi-chao, LI Zhi
    2011, 31(2): 190-196. https://doi.org/10.13249/j.cnki.sgs.2011.02.190
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    Soil respiration rates at 6 different land-use (i.e., cropland, orchard, abandoned farmlands, plantation, natural forest and grassland) in the lower reaches of the Tarim River were measured with an automated CO2 efflux system (LI-COR 8100), and the temperature, soil moisture, pH, salt content, organic content, total nitrogen content, available nitrogen content and soil texture were measured at the same time.The results showed that the diurnal variation of soil respiration rate of cropland, orchard, abandoned farmlands, plantation, natural forest and grassland, showed a single-peaked curve, were significant differences.The air temperature and land use types were main factors affected the differences of diurnal variation of soil respiration rate, in which the land use types changed the diurnal soil respiration through changing the soil properties including soil temperature, moisture, pH, salt content and texture.
  • Spatial Distribution and Variation of Concentration of Suspended Solids in Taihu Lake based on HJ-1 Satellite Data
    XIA Rui, LI Yun-mei, WU Chuan-qin, JIN Xin, WANG Yan-fei
    2011, 31(2): 197-203. https://doi.org/10.13249/j.cnki.sgs.2011.02.197
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    Taking Taihu Lake as the study area, this paper built linear model based on the satellite data of band 4 of HJ-1, to inverse the concentration of suspended solids and studied the spatial distribution of suspended solids in different months.By extracting each sample’s concentration by sampling equidistantly, the spatial variation can be known by geostatistics.The result shows that the concentration of suspended solids was very high during 2009, and the main grades were 30-50 mg/L and 50-70 mg/L.The distribution of high value zone spread from the northwest or southwest to the center of Taihu Lake.At last, a large area of high value zone was formed in the lake center finally.By the geostatistics theory, we can find that the spatial variation of suspended solids in Taihu Lake existed objective.Not only has it nugget effect, but also it has a strong spatial correlation.The ranges of variation in 2009 were greater than 20 km, except June in which that was 9.2 km.
  • Methodology of Earthquake Evacuation Zoning Based on GIS
    HUANG Jing, YE Ming-wu, WANG Jun, XU Shi-yuan, CHEN Zhen-lou, LIU Yao-long
    2011, 31(2): 204-210. https://doi.org/10.13249/j.cnki.sgs.2011.02.204
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    With rapid urbanization and frequent earthquake disasters,the pre-disaster study of emergency evacuation has become a substantial topic of disaster prevention and mitigation in urban area.Most of the previous studies emphasized large-scale evacuation involving one or more urban areas,while the research that is specific to basic level district,such as a community,is obviously inadequate in terms of evacuation accuracy,efficiency and strategies.In this paper,based on the current layout of emergency evacuation facilities and nighttime evacuation demands in urban community,we used GIS spatial analysis technology to develop a systematical methodology for community evacuation against earthquake.The methodology emphasized the following aspects: the distribution analysis of emergency evacuation demands,the calculation of shelters’space accessibility,and the optimization of evacuation destinations.Meanwhile,we applied the methodology to Lujiazui Street of Pudong New District,Shanghai in China.Consequently,the study showed that the proposed methodology could be used to formulate the pre-event planning for earthquake disasters’prevention and mitigation on community scale,especially for organizing a rapid and smooth evacuation,and optimizing the location allocation of shelters.
  • Based Space-time Elements of Climate Change in China on Hopfield Neural Network in Recent 40 Years
    ZHANG Chong, LI Jing, REN Zhi-yuan
    2011, 31(2): 211-217. https://doi.org/10.13249/j.cnki.sgs.2011.02.211
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    Using the daily precipitation, temperature and relative humidity data of 194 meteorological stations from 1961 to 2000 in China (not including Hong Kong, Macao, Taiwan and Hainan), based on the Spatial Kriging interpolation method in ArcGIS, and through the cluster of Hopfield neural networks as well as analysis of variance, the spatial and temporal characteristics of climate change in China.The results show that a dominant trend of warming occurrs in China, followed by the wet trend, drying trend occurrs in the eastern region, while the western region is gradually humidifying.Judging from the decadal results, we got that there was an equal trend between the trend of dry cooling and wet humid heat from 1960 to 1969; dry-type distribution from 1970 to 1979 was very broad, almost throughout the country; climate change types presented a layered distribution from 1980 to 1989, and according to the main types, warming trend was in the leading position; from 1990 to 2000, warming trend still dominated, followed by drying trend.We conducted clustering analysis using Hopfield neural network method, and test whether differences among the three kinds of climatic factors are significant using analysis of variance.In the final, according to the clustering results, we have analyzed the trend of precipitation, temperature and relative humidity change, results in line with interpolation show the space Kriging credibility.The results show that, driven by global warming, patterns of climate change in China is in a state of adjustment, and humid regions become arid, whereas arid regions humid.
  • A Local Topography-based Variable Outflow Width Method for Determining Multiple Flow Directions of DEM
    CHENG Hai-zhou, XIONG Li-hua
    2011, 31(2): 218-225. https://doi.org/10.13249/j.cnki.sgs.2011.02.218
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    It is one of the important contents in the topography analysis as well as in the hydrological distribution models that how to determine flow directions of water in each cell of DEM.Although many hydrologists have already put forward a lot of different flow direction algorithms over the past dozens of years.A new approach of assigning flow directions of DEM cell is proposed in this study, which is called local topography-based variable flow width method.This approach is based on the analysis of the local topography formation defined within a 3?3 cell window with the recognition that the flow distribution coefficient for each flow direction is changeable with the corresponding slope and outflow width.In the paper, this method has been tested on the digital topography of an actual watershed.Two indices, the total catchment area (TCA) and specific catchment area (SCA), produced by four flow routing algorithms including the D8 (eight flow directions), Dinf (an infinite number of possible single flow directions), MS (multiple flow directions based on slope) and the local topography-based variable flow width method, are selected to compare and analyze efficiencies of those four algorithms.The result shows that the local topography-based variable flow width method can obtain more reasonable spatial distribution of water accumulation, compared with the D8, Dinf, and MS.
  • Distribution and Relationship of Heavy Metals in Wheat in the Changjiang River Delta—A Case Study of Kunshan
    WANG Xiao-rui, ZhOU Sheng-lu, WU Shao-hua
    2011, 31(2): 226-231. https://doi.org/10.13249/j.cnki.sgs.2011.02.226
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    Rapid economic development and increased human activities of Changjiang River Delta made a strong influence on the ecological environment.Taking Kunshan of Suzhou City for example, this study was conducted to search for the heavy metal accumulation in soil and bioaccumulation of wheat in Changjiang River Delta, which will provide a theoretical guidance for economy development and pollution control.The heavy metal in the organs of root, stem, leaf and grain of wheat were studied.In each organ, the eight kinds of heavy metals were examined:Hg, As, Cr, Cu, Ni, Pb, Zn, Cd, and the absorption of heavy metals in different organs were analyzed.The results indicated that the root had the greatest accumulating capability; the absorption of Cd was the maximal while that of Cr was the minimal in each organ.Meanwhile, an analysis on correlations showed there is correlation between content of heavy metal in grain and that in the other organs of wheat, but have no certain rule.This indicates the complexity of outer contaminants and reactions in plant.By the evaluation on the potential risks of heavy metals in wheat, the potential risks of Hg, Zn and Cd have been above moderate levels.Moreover, the potential risk of eight kinds of heavy metals reached a higher level, based on which the author proposed to control heavy metal emissions of this area.
  • Runoff Characteristic in Flood and Dry Seasons in Source Regions of Changjiang River and Huanghe River Based on Wavelet Analysis
    BING Long-fei, SHAO Quan-qin, LIU Ji-yuan, ZHAO Zhi-ping
    2011, 31(2): 232-238. https://doi.org/10.13249/j.cnki.sgs.2011.02.232
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    By decomposing and reconstructing the runoff information from 1965 to 2007 of the hydrologic stations of Tuotuohe,Zhimenda in the source region of Changjiang River,and Jimai,Tangnaihai in the source region of Huanghe River with db3 wavelet,the runoff data of different hydrologic stations were analysized.The result shows that the runoff declines in spring flood season,summer flood season and dry season except for those in Tuotuohe.The order of declining flood/dry season is summer > spring > dry.While runoff of Tuotuohe is always increasing in different stages from 1965 to 2007 with higher increase rate in summer flood season than that in spring one.Complex Morlet wavelet is selected to detect runoff periodicity of the four hydrologic stations mentioned above.Totally the periodicity is 11–12 years in the source region of Huanghe River,while 4–6 years in the spring flood season and 13–14 years in summer flood season in the source region of Changjiang River.The major periodicity in spring,summer and dry season is distinctive greatly in different basins.
  • Spatial Pattern of the Neolithic Cultural Sites in the Middle and Lower Reaches of Hanjiang River
    LI Zhong-xuan, ZHU Cheng, YAN Hui
    2011, 31(2): 239-243. https://doi.org/10.13249/j.cnki.sgs.2011.02.239
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    Using trend surface method, this article discusses spatial process of the Neolithic Site i.e.Daxi culture (6.3-5.0 ka B.P.), Qujialing culture (5.0-4.6 ka B.P.) and Shijiahe culture (4.6-4.0 ka B.P.)in the middle and lower reaches of the Hanjaing Rvier.This research found that the spatial evolution of the Neolithic culture was divided into two stages:(1) Qujialing sites were diffused towards upstream along the Hanjiang River and the Yunshui River; (2) Shijiahe Cultural sites were instead of shrink in the zone of Danjiang-Zaoyang-Yunshui belt.In relation to the Holocene climate and landscape change process, we find that the elevation of the sites above the river was close to the changes of ancient floods and lake area.Therefore, this paper suggested the spatial-temporal distribution of sites is mainly controlled by paleo-floods and lake-expanding, meanwhile social factors e.g.agricultural style and cultural integration also play important roles.
  • Geomorphic Analysis and Its Implication to Neotectonics in Middle of Northern Front of Liulengshan Mountain, Northern Shanxi
    YAN Dong-dong, LÜ Sheng-hua, ZHAO Hong-zhuang, LI You-li
    2011, 31(2): 244-250. https://doi.org/10.13249/j.cnki.sgs.2011.02.244
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    Quantitative study on the geomorphic indices has been carried out on five gullies in the middle of northern front of Liulengshan Mountain.The abnormal values of the indices, including stream length-gradient index (SL index), hypsometric integral (HI), and index of drainage basin shape (Bs), reveal that the evolution of the five gullies has obvious relationship with the neotectonic movement along the northern front of Liulengshan Mountain and the drainage basins are currently in the mature period of geomorphic evolution.The field investigation of the Qiulin gully tests demonstrates the Late Quaternary activities of the fault along the northern front of Liulengshan Mountain.
  • A 645-Year Precipitation Reconstruction in Baluntai Region on Southern Slope of Mid-Tianshan Mountains Based on Tree-ring Width
    ZHANG Tong-wen, WANG Li-li, YUAN Yu-jiang, WEI Wen-shou, YU Shu-long, ZHANG Rui-bo, CHEN Feng, SHANG Hua-ming, FAN Zi-ang
    2011, 31(2): 251-256. https://doi.org/10.13249/j.cnki.sgs.2011.02.251
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    Dendroclimatology is one of the important methods for examining the past global climate changes and the tree-ring data were used widely as an important archive in paleoclimatic research because of its precise dating, annual resolution, and high correlation with instrumental meteorological data.Based on tree-ring chronologies, long-timescale climate variations have been reconstructed on both regional and hemispheric spatial scales.The study area, the Baluntai region is located on the southern slope of the mid-Tianshan Mountains in Xinjiang.So far there are a few dendroclimatogical studies being carried out in this region.The studies were focused on the analysis of tree-ring chronologies’statistics and correlation of chronologies with meteorological data, but the reconstruction of climatic variations has not been done.Because of this, it is very important to reconstruct the climatic variation series in this region in order to recognize the climatic variations on the southern slope of the mid-Tianshan Mountains in the past.In the summer of 2005, 66 spruce (Picea schrenkiana) tree-ring samples were collected from Fustan Gully (FST) (42°45’15.9"N, 86°27’40.0"E), which is located in a mountainous area of Baluntai region.Selected trees did not have outward signs of disturbance (e.g., abrasion scarring, cut branches).Tree-ring samples were prepared, cross-dated and measured following conventional procedures.The site (FST) of tree-ring width residual chronologies was chosen in this study.In addition, meteorological data of Baluntai station close to sampling site were used.The calculation shows that the tree-ring width residual chronology (RESt+1) is significantly correlated with the precipitation from the current July to next June (r=0.73, p<0.01, N=44).In this paper, tree-ring width residual chronology (RESt+1) has been used to reconstruct the precipitation (from the current July to next June) of this region since 1360 A.D.and the explained variance of the function was 52% (F=48.12, p<0.01).After 21-years mean of reconstructed precipitation series was calculated, twelve dry periods in the past 645 years were found in (1370?)-1396, 1442-1469, 1501-1539, 1565-1586, 1619-1652, 1679-1688, 1707-1728, 1755-1788, 1811-1836, 1863-1886, 1907-1918 and 1940-1987, and twelve wet periods were found in 1397-1441, 1470-1500, 1540-1564, 1587-1618, 1653-1678, 1689-1706, 1729-1754, 1789-1810, 1837-1862, 1887-1906, 1919-1939 and 1988-(1994?), respectively.Power spectrum analysis shows that there exist the 16.5-17.2 a, 10.7-11 a, 6.7 a, 2.4-6.6 a and 2.1 a quasi-cycles in precipitation.The periods of 10.7 a to 11 a respond to sunspot cycle length (SCL) and the cycle of aridity in Northwest China.The periods of 2.4 a to 6.7 a probably are related to ENSO events, and the cycle of 2.1 years probably is related to the quasi-biennial oscillation (QBO).Moving t-test technique (MTT) shows that the abrupt change of precipitation occurred in 1496 in this region.