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  • 2012 Volume 67 Issue 11
    Published: 20 November 2012
      
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  • Variations in January Temperature and 0℃ Isothermal Curve in Qinling Mountains Based on DEM
    BAI Hongying, MA Xinping, GAO Xiang, HOU Qinlei
    2012, 67(11): 1443-1450. https://doi.org/10.11821/xb201211001
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    Based on the records of January average temperature during 1959 to 2009 from 39 meteorological sites in the Qinling Mountains, we built the spatial database of January temperature by using space interpolation method based on DEM with the consideration of the influence of terrain factors on the temperature field. Also we extracted the 0℃ isothermal curve and examined the changes in the January average temperature and the 0℃ isothermal curve in the Qinling Mountains during the last 50 years. The January average temperature showed a rising trend at a rate of about 0.2℃/10a, and the 0℃ isothermal curve rose by 143.7 m averagely in the Qinling Mountains during the last 50 years. On longitude, the largest variation in the 0℃ isothermal curve was found in the region of 107°-109°E, where the height increased by 166.2 m during the last 50 years. This value is significantly higher than that in both eastern and western sections of Qinling Mountains; the temporal mutations point for the largest increase in the January temperature was found in 1993. The 0℃ isothermal curve after the mutations point was raised higher by 113.82 m averagely than before.
  • Assessing Climate Change Impact on Seasonal Drought in Main Rice Cropping Regions in the South of China
    MA Xin, WU Shaohong, LI Yu'e, ZHANG Xueyan, GAO Qingzhu, WU Yang
    2012, 67(11): 1451-1460. https://doi.org/10.11821/xb201211002
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    Impact of climate change on seasonal drought in main rice cropping regions in China is important for adjusting rice planting pattern and improving adaptation ability. By comparing the level and spatial and temporal distribution of available water and seasonal drought during 1981-2030, this paper assesses impact of climate change on seasonal drought in main rice cropping regions in the south of China. The results are shown as follows. (1) The mean available water of early rice and late rice will increase by more than 10% in the growing season, while mean available water of medium rice will keep invariant. Meanwhile, the spatial distribution of available water of early rice and later rice becomes more homogeneous. This means that, due to climate change, available water of main rice cropping regions generally in the growing season will be more abundant, and spatial distribution of available water is more homogeneous, which is conductive to mitigate seasonal drought. (2) The area of seasonal drought of early rice will reduce by 12,500 km2, medium rice by 80,000 km2, and especially later rice will decrease by 250,000 km2, accounting for 20% of the planting area of later rice. This means that, under climate change, the seasonal drought on the whole will tend to weaken, especially seasonal drought of later rice will obviously be weakened. (3) Based on the relationship between available water from hydrologic circulation process and water demands for crop growing season, the Water Supplies and Demands Index (WSDI) is suitable for assessing the impact of climate change on seasonal drought in main rice cropping regions.
  • The Effect of Climate Change during Snowmelt Period on Streamflow in the Mountainous Areas of Northwest China
    LI Baofu, CHEN Yaning, CHEN Zhongsheng, LI Weihong
    2012, 67(11): 1461-1470. https://doi.org/10.11821/xb201211003
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    This paper, using daily mean temperature and precipitation from 8 mountainous weather stations over the period 1960-2010 in the arid region of Northwest China, analyzes snowmelt period tendency and its spatial variations and explores the sensitivity of runoff to length, temperature and precipitation of snowmelt period. The results show that mean onset of snowmelt period has a shift of 15.33 days earlier while mean ending date has moved 9.19 days later. Onset of snowmelt period in southern Tianshan Mountains moved 20.01 days earlier while that in northern Qilian Mountains moved only 10.16 days earlier. Mean precipitation and air temperature increases by 47.3 mm and 0.857℃ in the mountainous areas of Northwest China, respectively. The precipitation of snowmelt period with the largest increase was observed in southern Tianshan Mountains, reaching 65 mm, the precipitation and temperature in the northern Kunlun Mountains with the smallest increment increased by 25 mm and 0.617℃, respectively, while the temperature in northern Qilian Mountains rose the highest, an increase of 1.05℃. The annual streamflow is also sensitive to the variations of precipitation and temperature of snowmelt period, because variation of snowmelt period precipitation induce annual streamflow to change by 7.69% while change of snowmelt period temperature results in annual streamflow change by 14.15%.
  • Impact of Climate Change on Actual Evapotranspiration on the Tibetan Plateau during 1981-2010
    YIN Yunhe, WU Shaohong, ZHAO Dongsheng, ZHENG Du, PAN Tao
    2012, 67(11): 1471-1481. https://doi.org/10.11821/xb201211004
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    To quantify the impact of climate change on the evapotranspiration process of alpine ecosystems on the Tibetan Plateau, we performed a series of simulations with the LPJ dynamic vegetation model and 80 meteorological stations from 1981 to 2010. Changes in actual evapotranspiration and the difference between precipitation and actual evapotranspiration (P-E) on the Tibetan Plateau were analyzed. Over the last 30 years, climate change was characterized by significantly increased temperature, slightly increased precipitation and decreased potential evapotranspiration which was significant before 2000. Actual evapotranspiration had increasing trends in most parts of the Tibetan Plateau, and P-E mainly had decreasing trends in southeastern plateau and increasing trends in northwestern plateau. Descending atmospheric water demand would lead to a decreasing trend in actual evapotranspiration; however, it increased in most regions due to more precipitation. Actual evapotranspiration increased (decreased) in most regions where there was 86% (73%) of increased (decreased) precipitation.
  • The Temporal and Spatial Change of Temperature and Precipitation in Hexi Corridor in Recent 57 Years
    MENG Xiujing, ZHANG Shifeng, ZHANG Yongyong
    2012, 67(11): 1482-1492. https://doi.org/10.11821/xb201211005
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    In this study, monthly temperature and precipitation time series from 1955 to 2011 of 12 meteorological stations were collected and means of linear regression, moving average, Mann-Kendall test, accumulated variance analysis and Pettitt were used to diagnose the behavior of temperature and precipitation so as to reveal the regional climate change facts and its trends. The results showed that the average annual temperature in the Hexi Corridor increased significantly in recent 57 years, and its increasing rate was 0.27℃/10a which was twice the level of the IPCC Fourth Assessment Report announced, and its abrupt changes were mainly detected in 1986. The seasonal average temperature in this region had an evident uptrend and the trend was most significant in winter. The annual average precipitation change trend rate was 3.95 mm/10a which had a significant rising trend at statistical significance level, but it was insignificant in its three basins. The rainy season precipitation which had the same fluctuation change as the annual precipitation presented no significant uptrend. There were no consistent abrupt changes observed of the precipitation in this study area, but the rainy season precipitation abrupt changes were mainly observed in 1968. With the increase of temperature and precipitation, warming and wetting is evident in this study area.
  • Palaeoflood Sedimentological and Hydrological Studies on the Yongheguan Reach in the Middle Yellow River
    HUANG Chunchang, LI Xiaogang, PANG Jiangli, ZHA Xiaochun, ZHOU Yali
    2012, 67(11): 1493-1504. https://doi.org/10.11821/xb201211006
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    Typical palaeoflood slackwater deposits of the Holocene age were found at many sites on both sides of the Shanxi-Shaanxi Gorges. A set of 5 beds palaeoflood SWD at the Yongheguang (YHG) site was sampled and investigated in detail. Analyses of the grain-size distribution, loss-on-ignition and CaCO3 content indicate that these SWD consist of sandy silt and silt fine sand. They were sourced from the suspended sediment load of the Yellow River floodwater, which was brought in by storm rains and floods from the triangle zone between Shanxi, Shaanxi and Inner Mongolia. They have recorded 5 extraordinary palaeoflood events on the Yellow River. The age of the palaeoflood events was determined by OSL dating of the sediment and stratigraphic correlation with the Holocene chronological framework established in the drainage basin of the middle reaches of the Yellow River. This shows that these extreme floods occurred during 3200-3000 a BP at the turn from the middle Holocene climatic optimum to the late Holocene dry period, which is the time of climatic decline from the Shang Dynasty to Western Zhou Dynasty, with occurrence of serious drought and flood disasters, harvest failure, famine and major social changes. The reconstructed peak discharges of the palaeoflood range from 28380 to 48590 m3/s, which are much larger than the gauged largest floods in the Shanxi-Shaanxi Gorges in the middle reaches of the Yellow River, thus the flood data series of the river extended to a 10000-year time-scale.
  • Trend Analysis for the Annual Discharge Series of the Yangtze River at the Yichang Hydrological Station Based on GAMLSS
    JIANG Cong, XIONG Lihua
    2012, 67(11): 1505-1514. https://doi.org/10.11821/xb201211007
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    It is very important to study the trends of the inconsistent hydrological series under the changing environments. The conventional methods of trend analysis can only be used to analyze the linear trends of the mean value of hydrological series. In this paper, GAMLSS is introduced to analyze the trends in both the annual average discharge series and the annual minimum monthly discharge series of the Yangtze River at the Yichang hydrological station. GAMLSS can detect not only the time variation of the mean value of the discharge series, but also the time variation of other statistical parameters, such as standard deviation (or coefficient of variation) and coefficient of skew. Model results indicate that the mean of the annual mean discharge series decreases linearly with time, and the annual minimum monthly discharge series do not show any significant linear trend of decrease or increase.
  • Bibliometric Analysis of Research Progress on Ecological Vulnerability in China
    TIAN Yaping, CHANG Hao
    2012, 67(11): 1515-1525. https://doi.org/10.11821/xb201211008
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    Taking CNKI as the main data source, this paper uses bibliometric methods to examine the present situation and the development of research on ecological vulnerability in China. Results show that ecological vulnerability has become a hotspot in China since 1989, and the research can be divided into three development stages. The initial stage (1989-2000) was mainly focused on qualitative research on preliminary theory discussion and regional countermeasures; the rapid development stage (2001-2007) was concentrated on method application and empirical evaluation, characterized by a large increase in literature numbers; the period since 2008 saw a boom of theoretical reviews and initial signs of comprehensive research. In the development process, the empirical research on vulnerability evaluation developed rapidly, whose research scope tended to be more comprehensive and balanced gradually instead of focus on the karst region in Southwest China and agro-pastoral zigzag zone in northern China. But on the whole the development of the theory research lags behind that of the method application, thus, at present, the empirical research method of ecological vulnerability evaluation in China are lack of theory standard, and the empirical research on ecological vulnerability still focus more on the single ecological system, and in existing comprehensive indexes of vulnerability evaluation, natural and economic indexes weight and its regional differences are relatively big, and social indicators weight and its regional differences are smaller.
  • Coppice Dune Formation and Its Significance to Environmental Change Reconstructions in Arid and Semiarid Areas
    LANG Lili, WANG Xunming, Hasi, HUA Ting
    2012, 67(11): 1526-1536. https://doi.org/10.11821/xb201211009
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    Environments in arid and semiarid areas are extremely sensitive to climate change. High wind activity in these regions has resulted in an extensively developed arid geomorphology, but past environmental changes are poorly understood because of the absence of relatively high-resolution proxies. The accumulation characteristics of nebkhas, which have developed extensively in these regions, can be used to reconstruct environmental changes. Here we summarized recent advances in research on the formation, development, and sediment characteristics of nebkhas and their significances to environmental changes in arid and semiarid areas. Based on the previous studies, we suggested that research on nebkha formation can provide distinct clues about environmental changes in arid and semiarid areas; however, further studies are needed.
  • Analysis of Environmental Kuznets Effect of Tourism Waste: Case Study of Huangshan National Park
    ZHANG Jinhe, LI Man, CHENG Jing, ZHOU Jing, WANG Nannan
    2012, 67(11): 1537-1546. https://doi.org/10.11821/xb201211010
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    Tourism waste is by-product of resources consumption and digested by environment, which is the root causes for tourism waste generating environmental and ecological impact. There is a growing interest in tourism waste and it is a new frontier in the field of tourism geography. This paper puts forward and selects six variable indicators, namely tourism solid waste, wastewater, excrement, SO2, NOx and dust, which include three kinds (solid, liquid and gas) of tourism waste and express the quality of the environment, and chooses per capita tourism income to express the development of tourism economy. The aim of this study is to identify the relationship between the environmental quality indicators and per capita tourism income. It, taking the Huangshan National Park as an example, uses the time series data from 1979 to 2010, and tests the environmental Kuznets curve fitting of tourism waste. Four conclusions can be summarized. (1) There is environmental Kuznets inverted U-shaped relationship between the solid and liquid tourism waste emissions and tourism development, but not for the gaseous tourism waste. (2) The turning point of the inverted U-shaped curve of solid waste emissions is 4596.01 t, wastewater emissions is 731491.46 t, and excrement emissions is 15866.43t, with the turning year of 2015. (3) Application of technology plays a larger role in the improvement of ambient air quality in the scenic spot. When energy consumption decreased by 1% per ten thousand yuan, variable values of SO2, NO2 and PM10 would decrease by 3.38%, 4.25% and 0.78%, respectively. Environmental regulation has significant effect on the quality control of the scenic surface water. The rate of wastewater discharge standards increased by 1% as the COD value of the surface water decreased by 3.41%. (4) Tourism waste emissions do not inevitably lead to the decline of the scenic environmental quality, thus restructuring the tourism industry, increasing scientific and technological applications and to strengthen environmental regulation are key means to control environmental pollution and ecological impact of tourism wastes.
  • Spatial Distribution of Soil Total Nitrogen in a Typical Watershed of the Middle Danjiang River
    XU Guoce, LI Zhanbin, LI Peng, HUANG Pingping, LONG Feifei
    2012, 67(11): 1547-1555. https://doi.org/10.11821/xb201211011
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    Field sampling was carried out based on a 100 m × 100 m grid system and typical spot samples. A total of 268 sites were sampled in Yingwugou watershed. The samples were collected in three soil layers at a depth of 0-40 cm. Both traditional and geostatistical methods were applied to analyze total nitrogen in the three different soil depths. The results indicated that the total nitrogen content in the soil profile decreased with the increase of soil depth, and there were significant differences among the three soil layers (P < 0.01). The mean total nitrogen contents in 0-10 m (A1), 10-20 m (A2) and 20-40 cm (A3) were 0.85, 0.47 and 0.30 g/kg, respectively. The best fitted models in the three soil layers were all linear models indicating moderate spatial dependence. The Kriging interpolation showed that the spatial distribution of soil total nitrogen content in different soil layers exhibited ribbon-shaped patterns. The ANOVA showed that the spatial variations of the total nitrogen content for different land use types in A1 and A2 were significant (P < 0.05). The impact of slope on soil total nitrogen content in the three soil depths was significant (P < 0.05). There were significant correlations between the total nitrogen content and elevation, slope and aspect in different soil layers of cropland (P < 0.01). The soil total nitrogen storage in the study are at 0-40 cm was 562.37 t. The total nitrogen contents per square meter at the 0-40 cm soil layer for forestland, cropland and grassland were 0.343, 0.299 and 0.289 kg/m2, respectively.
  • Mass Elevation Effect and Its Contribution to the Altitude of Timberline in the Northern Hemisphere
    ZHAO Fang, ZHANG Baiping, PANG Yu, YAO Yonghui, HAN Fang, ZHANG Shuo, QI Wenwen
    2012, 67(11): 1556-1564. https://doi.org/10.11821/xb201211012
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    Alpine timberline, as the "ecological transition zone," has long attracted attention of scientists in many fields of study, especially scientists of climatic change in recent years. Many unitary and dibasic fitting models have been developed between timberline and its influencing factors. It has been commonly believed that latitude or temperature is a decisive factor for the altitudinal distribution of timberline, and most of the fitting models involve the relationship between timberline and latitude or temperature. However, these models are usually on regional scale and could not be extended to other regions; on the other hand, hemispherical-scale and continental-scale models usually contain only about 100 timberline data and results in low precision. The present article has collected 516 data points of timberline, and takes latitude, continentality and mass elevation effect as independent variables and timberline elevation as dependent variables to set up a ternary linear regression model. Continentality is calculated using the meteorological data released by WorldClim and mountain base elevation (as alternative factor of the mass elevation effect) is extracted on the basis of SRTM 90-meter resolution elevation data. The results show that the coefficient of determination (R2) of the linear model is as high as 0.904, and that the contribution rate of latitude, continentality and mass elevation effect to timberline elevation is 45.02% (p = 0.000), 6.04% (p = 0.000) and 48.94% (p = 0.000), respectively. This revealed that the influence of mountain mass elevation effect on timberline distribution exceeds that of latitude and continentality put together, and that mass mountain effect is the primary factor in determining the elevation distribution of timberline on continental and hemispherical scale. The contribution rate of the mass elevation effect to the timberlines is, although different in different regions, generally high, e.g., 50.49% (p = 0.000) in North America, 48.73% (p = 0.000) in the eastern Eurasia, and 43.6% (p = 0.000) in the western Eurasia.