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2016, 8 (4) Online: 01 August 2016 Previous issue Next issue
  • Evolution of permafrost in Northeast China since the Late Pleistocene
  • HuiJun Jin, XiaoLi Chang, DongLiang Luo, RuiXia He, LanZhi Lü, SiZhong Yang, DongXin Guo, XueMei Chen, Stuart A. Harris
  • DOI: 10.3724/SP.J.1226.2016.00269
  • 2016, Vol.8 (4): 269–296 Abstract ( 44) HTML PDF (18957 KB) ( 8 )
  • In Northeast China, permafrost advanced and retreated several times under the influences of fluctuating paleo-climates and paleo-environments since the Late Pleistocene. During the last 60 years, many new data were obtained and studies were conducted on the evolution of permafrost in Northeast China, but so far no systematic summary and review have been made. Based on sedimentary sequences, remains of past permafrost, paleo-flora and -fauna records, and dating data, permafrost evolution since the Late Pleistocene has been analyzed and reconstructed in this paper. Paleo-temperatures reconstructed from the remains of past permafrost and those from paleo-flora and -fauna are compared, and thus the southern limit of permafrost (SLP) in each climate period is inferred by the relationship of the permafrost distribution and the mean annual air/ground temperatures (MAAT/MAGT). Thus, the evolutionary history of permafrost is here divided into five stages:(1) the Late Pleistocene (Last Glaciation, or LG) (65 to 10-8.5 ka), the Last Glaciation Maximum (LGM, 21-13 ka) in particular, the coldest period in the latest history with a cooling of about 6~10℃, characterized by extensive occurrences of glaciation, flourishing Mammathas-Coelodonta Faunal Complex (MCFC), widespread aeolian deposits, and significant sea level lowering, and permafrost greatly expanded southwards almost to the coastal plains (37°N-41°N); (2) the Holocene Megathermal Period (HMP, 8.5-7.0 to 4.0-3.0 ka), 3~5℃ warmer than today, permafrost retreated to about 52°N; (3) the Late Holocene Cold Period (Neoglaciation) (4.0-3.0 to 1.0-0.5 ka), a cooling of 1~3℃, some earlier thawed permafrost was refrozen or attached, and the SLP invaded southwards to 46°N; (4) the Little Ice Age (LIA, 500 to 100-150 a), the latest cold period with significant permafrost expansion; and (5) climate warming since the last century, during which Northeast China has undergone extensive permafrost degradation. The frequent and substantial expansions and retreats of permafrost have greatly impacted cold-region environments in Northeast China. North of the SLP during the HMP, or in the present continuous permafrost zone, the existing permafrost was largely formed during the LG and was later overlapped by the permafrost formed in the Neoglaciation. To the south, it was formed in the Neoglaciation. However, many aspects of permafrost evolution still await further investigations, such as data integration, numerical reconstruction, and merging of Chinese permafrost history with those of bordering regions as well as collaboration with related disciplines. Of these, studies on the evolution and degradation of permafrost during the past 150 years and its hydrological, ecological, and environmental impacts should be prioritized.
  • Uncertainty analysis of runoff and sedimentation in a forested watershed using sequential uncertainty fitting method
  • Tanveer Abbas, Ghulam Nabi, Muhammad W. Boota, Fiaz Hussain, Muhammad I. Azam, HuiJun Jin, Muhammad Faisal
  • DOI: 10.3724/SP.J.1226.2016.00297
  • 2016, Vol.8 (4): 297–310 Abstract ( 34) HTML PDF (4685 KB) ( 16 )
  • The Soil and Water Assessment Tool (SWAT) was implemented in a small forested watershed of the Soan River Basin in northern Pakistan through application of the sequential uncertainty fitting (SUFI-2) method to investigate the associated uncertainty in runoff and sediment load estimation. The model was calibrated for a 10-year period (1991-2000) with an initial 4-year warm-up period (1987-1990), and was validated for the subsequent 10-year period (2001-2010). The model evaluation indices R2 (the coefficient of determination), NS (the Nash-Sutcliffe efficiency), and PBIAS (percent bias) for stream flows simulation indicated that there was a good agreement between the measured and simulated flows. To assess the uncertainty in the model outputs, p-factor (a 95% prediction uncertainty, 95PPU) and r-factors (average wideness width of the 95PPU band divided by the standard deviation of the observed values) were taken into account. The 95PPU band bracketed 72% of the observed data during the calibration and 67% during the validation. The r-factor was 0.81 during the calibration and 0.68 during the validation. For monthly sediment yield, the model evaluation coefficients (R2 and NS) for the calibration were computed as 0.81 and 0.79, respectively; for validation, they were 0.78 and 0.74, respectively. Meanwhile, the 95PPU covered more than 60% of the observed sediment data during calibration and validation. Moreover, improved model prediction and parameter estimation were observed with the increased number of iterations. However, the model performance became worse after the fourth iterations due to an unreasonable parameter estimation. Overall results indicated the applicability of the SWAT model with moderate levels of uncertainty during the calibration and high levels during the validation. Thus, this calibrated SWAT model can be used for assessment of water balance components, climate change studies, and land use management practices.
  • Study of annual mass balance (2011-2013) of Rikha Samba Glacier, Hidden Valley, Mustang,Nepal
  • Sanjaya Gurung, Bikas C. Bhattarai, Rijan B. Kayastha, Dorothea Stumm, Sharad P. Joshi, Pradeep K. Mool
  • DOI: 10.3724/SP.J.1226.2016.00311
  • 2016, Vol.8 (4): 311–318 Abstract ( 36) HTML PDF (2651 KB) ( 20 )
  • Although Himalayan glaciers are of particular interest in terms of future water supplies, regional climate changes, and sea-level rises, little is known about them due to lack of reliable and consistent data. There is a need for monitoring these glaciers to bridge this knowledge gap and to provide field measurements necessary to calibrate and validate the results from different remote sensing operations. Therefore, glaciological observations have been carried out by the Cryosphere Monitoring Project (CMP) since September 2011 on Rikha Samba Glacier in Hidden valley, Mustang district in western Nepal in order to study its annual mass balance. This paper presents the first results of that study. There are 10 glaciers in Hidden Valley, named G1, G2, G3, up to G10. Of these, G5 is the Rikha Samba Glacier, which has the largest area (5.37 km2) in this valley and the highest and lowest altitudes (6,476 and 5,392 m a.s.l., respectively). The glacier mass balance discussed in this paper was calculated using the glaciological method and the equilibrium line altitude (ELA). The glacier showed a negative annual point mass balance along the longitudinal profile of its lower part from September 10, 2011 to October 3, 2012. Stake measurements from October 4, 2012 to September 30, 2013 indicated a negative areal average of annual mass balance -0.088±0.019 m w.e. for the whole glacier. Based on these observations, the ELA of the Rikha Samba Glacier is estimated at 5,800 m a.s.l. in 2013. This negative balance may be due to rising air temperatures in the region, which have been incrementally rising since 1980 accompanied by little or no significant increase in precipitation in that period. The negative mass balance confirms the general shrinking trend of the glacier.
  • An investigation of the effects of dust storms on rat lung using HRCT and blood gas analysis
  • FengFeng Lei, WanYin Luo, ZhiBao Dong, YingZhu Sang, LiZhu Luo, Gang Huang, Hua Liu, QiZhang Chen
  • DOI: 10.3724/SP.J.1226.2016.00319
  • 2016, Vol.8 (4): 319–324 Abstract ( 36) HTML PDF (1730 KB) ( 16 )
  • The increasing intensity and frequency of sand-dust storms in China has led to greater prominence of associated environmental and health issues. Many studies have focused on the health effects of air particulate contaminants, but few formal investigations have studied the effects of sand-dust storms on human and animal health. The aim of this study was to investigate the effects of dust storms on rat lung by using high resolution computed tomography (HRCT) and blood gas analysis through a wind tunnel simulating. We found that the rat lung damage effects can be detected by the HRCT imaging after exposure to sand-dust storm environments, but had no obvious result through blood gas analysis. Exposure durations positively correlated with the damage degree to lung tissue. These will provide some evidence for clinical diagnosis of non-occupational pneumoconiosis.
  • Remote-sensing data reveals the response of soil erosion intensity to land use change in Loess Plateau,China
  • JiaLi Xie, ChangZhen Yan, ZhiXiang Lu, Sen Li
  • DOI: 10.3724/SP.J.1226.2016.00325
  • 2016, Vol.8 (4): 325–333 Abstract ( 33) HTML PDF (4806 KB) ( 24 )
  • Developing an effective approach to rapidly assess the effects of restoration projects on soil erosion intensity and their extensive spatial and temporal dynamics is important for regional ecosystem management and the development of soil conservation strategies in the future. This study applied a model that was developed at the pixel scale using water soil erosion indicators (land use, vegetation coverage and slope) to assess the soil erosion intensity in the Loess Plateau, China. Landsat TM/ETM+ images in 2000, 2005 and 2010 were used to produce land use maps based on the object-oriented classification method. The MODIS product MOD13Q1 was adopted to derive the vegetation coverage maps. The slope gradient maps were calculated based on data from the digital elevation model. The area of water soil-eroded land was classified into six grades by integrating slope gradients, land use and vegetation coverage. Results show that the Grain-To-Green Project in the Loess Plateau worked based on the land use changes from 2000 to 2010 and enhanced vegetation restoration and ecological conservation. These projects effectively prevented soil erosion. During this period, lands with moderate, severe, more severe and extremely severe soil erosion intensities significantly decreased and changed into less severe levels, respectively. Lands with slight and light soil erosion intensities increased. However, the total soil-eroded area in the Loess Plateau was reduced. The contributions of the seven provinces to the total soil-eroded area in the Loess Plateau and the composition of the soil erosion intensity level in each province are different. Lands with severe, more severe and extremely severe soil erosion intensities are mainly distributed in Qinghai, Ningxia, Gansu and Inner Mongolia. These areas, although relatively small, must be prioritised and preferentially treated.
  • Impact of soil conditions on the physiological characteristics of maize plants in an arid region, Northwest China
  • LiWen Zhao, ZhiBin He, WenZhi Zhao
  • DOI: 10.3724/SP.J.1226.2016.00334
  • 2016, Vol.8 (4): 334–342 Abstract ( 33) HTML PDF (4166 KB) ( 16 )
  • Overuse of irrigation water to ensure the crop yield of maize plants has caused serious water shortage problems in the middle reach of Heihe River, China. Thus, further research on the physiological characteristics, i.e., photosynthetic rate and leaf transpiration rate, are urgently needed to develop an efficient irrigation management system. In this paper, we selected two common soil textures (sandy loam, sand) and three one-time irrigation volumes (60 mm, 20 mm, 0 mm) in order to analyze the impact of soil conditions on the physiological characteristics of maize plants. Physiological and meteorological factors, soil water content and plant growing parameters were synchronously monitored on Jun. 30, Jul. 25 and Aug. 27 of 2012. The results indicate that sandy loam is better than sand for the growth of maize plants and single irrigation may provide limited influence on the physiological characteristics. Thus, increasing irrigation times and decreasing one-time volume is suggested for an efficient irrigation system.
  • Effects of artificial vegetation arrangement and structure on the colonization and development of biological soil crusts
  • Yang Zhao, Peng Zhang, YiGang Hu, Lei Huang
  • DOI: 10.3724/SP.J.1226.2016.00343
  • 2016, Vol.8 (4): 343–349 Abstract ( 32) HTML PDF (2578 KB) ( 20 )
  • The colonization and development of biological soil crusts (BSCs) are rarely discussed when investigating vegetation restoration with difference arrangement and structure of anthropogenically damaged areas in semi-arid regions. The present study analyzes the relationships among coverage, height and density of woody vegetation and coverage and thickness of BSCs on the surface mine dumpsite in Heidaigou, China. Results showed that PR (Prunus sibirica L.), PT (Pinus tabulaeformis Carr.) and PPr (P. tabulaeformis Carr., P. sibirica L.) types had the highest coverage of total BSCs, which were 76.8%, 75.9% and 78.9%, respectively and PR showed the thickest BSCs of 4.41 mm. There was a significant correlation between coverage and thickness of BSCs and coverage and height of woody vegetation as a unimodal curve. Our findings suggest that a single woody plant species and low level coverage and height (no more than 30% and 300 cm, respectively) of woody plants may be able to create suitable conditions for facilitating BSCs restoration on the surface of mine dumpsites. The effects of vegetation arrangement and structure on BSCs colonization and development should be considered in reconstructing and managing woody vegetation in disturbed environments, such as surface mine dumpsites in semi-arid areas.
  • The simulation of LUCC based on Logistic-CA-Markov model in Qilian Mountain area, China
  • HaiJun Wang, XiangDong Kong, Bo Zhang
  • DOI: 10.3724/SP.J.1226.2016.00350
  • 2016, Vol.8 (4): 350–358 Abstract ( 73) HTML PDF (3422 KB) ( 29 )
  • The Qilian mountain area was examined for using the Logistic-CA-Markov coupling model combined with GIS spatial analyst technology to research the transformation of LUCC, driving force system and simulate future tendency of variation. Results show that:(1) Woodland area decreased by 12.55%, while grassland, cultivated land, and settlement areas increased by 0.22%, 7.92%, and 0.03%, respectively, from 1986 to 2014. During the period of 1986 to 2000, forest degradation in the middle section of the mountain area decreased by 1,501.69 km2. Vegetation cover area improved, with a net increase of grassland area of 38.12 km2 from 2000 to 2014. (2) For constructing the system driving force, the best simulation scale was 210m×210m. Based on logistic regression analysis, the contribution (weight) of composite driving forces to land use and cover change was obtained, and the weight value was more objectively compared with AHP and MCE method. (3) In the natural scenarios, it is predicted that land use and cover distribution maps of Qilian mountain area in 2028 and 2042, and the Lee-Sallee index test was adopted. Over the next 27 years (2015-2042), farmland, woodland, grassland, settlement areas show an increasing trend, especially settlements with an obvious change of 0.56%. The area of bare land will decrease by 0.89%. Without environmental degradation, tremendous structural change of LUCC will not occur, and typical characteristic of the vertical zone of the mountain would remain. Farmland and settlement areas will increase, but only in the vicinity of Qilian and Sunan counties.