Table of Content

    20 September 2015, Volume 70 Issue 9 Previous Issue    Next Issue
    Climate Change
    The spatial and temporal variations of winter snowfall in agri-pasture transitional zone of North China
    Ji WANG, Liye HE, Xuemei ZHANG
    2015, 70 (9):  1363-1374.  doi: 10.11821/dlxb201509001
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    Using daily snowfall observations (1961-2012) of 227 meteorological observation stations which are treated by a series of climatic statistical methods, analysis is performed on the temporal and spatial characteristics of winter snowfall in the agri-pasture transitional zone of North China and its relations with circulation factors. The result shows that the high value center of snowfall is located in the northeast of Inner Mongolia in early winter, and then it moves to the southern part of North China at the end of winter and the beginning of spring. The periods of the 1960s and 1970s witnessed more snowfalls at all levels than normal, with high value centers moving eastward from West Inner Mongolia (in the 1960s) to most parts of Hebei and Shanxi provinces (in the 1970s). Since the 2000s, heavy snowfalls across North China have been the most significant in the north of Shanxi and Hebei provinces, with Hulunbuir coming next. Regarding variations of snowfall frequencies, there is a decline in the frequency of heavy snowfalls in different regions, with the most significant decrease occurring in Hebei province and the south of Shanxi province (named as the VI region in this paper). During the period with fewer snowfalls in North China (in the 1980s and 1990s), vapor transport was weak, moving from northwest to southeast; whereas during the years of strong vapor transport, the water transport in the past decade moved from southeast to northwest. The inter-decadal snowfall has a negative correlation with the air temperature and Arctic Oscillation (AO) index, whereas the snowfall at moderate and high levels is positively correlated with the air temperature and AO index in high latitude areas like the Greater Hinggan and Taihang Mountains in northeastern Inner Mongolia.

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    Loss evaluation of farmland caused by sea level rise and storm surge in the Pearl River Delta region under global climate change
    Lei KANG, Li MA, Yi LIU
    2015, 70 (9):  1375-1389.  doi: 10.11821/dlxb201509002
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    The Pearl River Delta region (PRD) is one of the regions seriously threatened by sea level rise and storm surges in Chinese coastal area in the context of global climate change, which causes huge loss of farmland and agricultural production. Based on the relevant research and experience, a loss evaluation model of farmland yield caused by sea level rise and storm surge was established. In this model, the submerged farmland area, cropland area and per unit yield of each kind of crops were concerned, while the impact of wind, flood time, changes of land use and plant structure were not considered during the long prediction term. Taking the PRD in Guangdong as the study area, this paper estimated and analyzed spatial distribution and losses of farmland in different scenarios in the years of 2030, 2050 and 2100, using the digital elevation model, land-use data, the local crop structure, rotation pattern, and yield loss ratio at different submerged heights obtained by field questionnaire investigation. The results showed that the proportion of submerged farmland and losses of agriculture production in the PRD would increase gradually from 2030 to 2100. Yangjiang, Foshan and Dongguan were the areas where submerged farmland increased obviously, while Guangzhou and Zhuhai were the areas with slow increase of submerged farmland. Besides, with sea level rising, the submerged farmland with higher submerged height increased, while that with lower submerged height declined. As for agricultural production, vegetables would have the greatest loss than rice and peanuts. From the point of cities, it was Jiangmen that had the greatest loss of rice. Shanwei and Jiangmen were the areas with serious loss of vegetables. Although the losses of peanut were generally smaller, Jiangmen, Guangzhou and Shanwei had the relatively high losses. At last, some suggestions were put forward, such as building sea wall and tidy gate in Jiangmen, Huizhou and Shanwei, enforcing ecological protection to mitigate storm surges and strengthening disaster warning.

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    Magnitude, frequency and timing of floods in the Tarim River, Xinjiang: Characteristics, causes and impacts
    Xihui GU, Qiang ZHANG, Peng SUN, Mingzhong XIAO, Dongdong KONG
    2015, 70 (9):  1390-1401.  doi: 10.11821/dlxb201509003
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    Nine flood indicators have been defined and trends in magnitude, frequency and timing of floods were predicted using Mann-Kendall trend test method in the Tarim River basin. Moreover, causes behind spatiotemporal variations of floods as well as the impacts of floods on socioeconomy of the Tarim River basin were also investigated. The results indicated that temperature and precipitation increased in the mid- and late 1980s and synchronous amplifications of floods were also identified with similar abrupt floods compared with precipitation and temperature changes. After the mid-1980s, the Tarim River basin experienced periods with frequent floods with evident and persistent increase of flood peak flow. Generally, floods are temperature-induced and rainstorm-induced, significant increase of precipitation extremes is the major driving factor behind rainstorm-induced floods, and increasing temperature is the principal factor behind temperature-induced floods as a result of fast melting of snowpack or glacier. Nevertheless, the floods with the potential to cause loss occurred in a clustering way after the mid-1980s and most of these floods were the results of heavy rain. Furthermore, heavy floods ranked as three record-high floods or floods with return periods more than 10 years usually occurred in similar periods at most of the stations across the basin.

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    Glacier changes in the Qilian Mountains in the past half century: Based on the revised First and Second Chinese Glacier Inventory
    Meiping SUN, Shiyin LIU, Xiaojun YAO, Wanqin GUO, Junli XU
    2015, 70 (9):  1402-1414.  doi: 10.11821/dlxb201509004
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    According to the Second Chinese Glacier Inventory (SCGI) that were mostly compiled based on Landsat TM/ETM+images, the Qilian Mountains contained 2684 glaciers covering an area of 1597.81±70.30βkm2 and ice volume of ~84.48βkm3 from 2005 to 2010. While most glaciers are small (85.66% are smaller than 1.0βkm2), some larger ones (12.74%, with each having 1.0 and 5.0βkm2) cover 42.44% of the total glacier area. The Laohugou No.12 Glacier (20.42βkm2) located on the north slope of the Daxue Range is the only one larger than 20 km2 in the Qilian Mountains. The average median altitude of glacier was 4972.7βm a.s.l. and gradually rose from east to west. Glaciers in the Qilian Mountains are mostly distributed in Gansu and Qinghai provinces, which have 1492 glaciers (760.96βkm2) and 1192 glaciers (836.85βkm2), respectively. In 11 watersheds, the Shule River contains most of the glaciers in either area or volume. However, the Heihe River, the second longest interior river in China, has the minimum average area of glacier. Comparison of glaciers from the SCGI and the revised glacier inventory based on topographic maps and aerial photos taken from 1956 to 1983 indicated that all the glaciers in the Qilian Mountains were receding, which is consistent with other mountains and plateaus in western China. In the past half century, the area and volume of glaciers decreased by 420.81βkm2 (-20.88%) and 21.63βkm3 (-20.26%), respectively. The glaciers which are smaller than 1.0βkm2 constituted the main body of glacier number depression and area recession. Due to shrinkage, the glaciers below 4000βm a.s.l. completely disappeared.

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    Mass balance of a typical monsoonal temperate glacier in Hengduan Mountains Region
    Jiankuo DU, Yuanqing HE, Shuang LI, Shijin WANG, Hewen NIU
    2015, 70 (9):  1415-1422.  doi: 10.11821/dlxb201509005
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    Research on Mt. Yulong is of great significance to evaluating the relationships between climate and glacier change in the Hengduan Mountains. Results show that the glacier mass had huge loss during the study period, varying from a minimum value of -1872 mm water equivalent (w.e.) to a maximum value of -907 mm w.e. The equilibrium line altitude of glacier was 4972 m in 2008, but it had been beyond the upper limit of the glacier since 2009. The accumulation occurred from October to the following May, while the ablation from June to September accounted for over 80% of the total amount of Baishui Glacier No.1. The mass balance vertical gradient was limited at the beginning and the end of the ablation period, and it is smaller in the ablation period compared with the whole year. The mean vertical gradient in this region was 1230 mm w.e. (100 m)-1 during 2008/2009, 2011/2012 and 2012/2013.

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    Simulated effects of agricultural development on surface air temperature over Central and Eastern China in the late 20th century
    Xuezhen ZHANG, Jiyuan LIU, Zhe XIONG, Hongwen ZHANG
    2015, 70 (9):  1423-1433.  doi: 10.11821/dlxb201509006
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    We studied the effects of agricultural development on surface air temperature over Central and Eastern China in the late 20th century by performing four long-term (1980-2000) simulations using the Weather Forecast and Research (WRF) model. The four simulations used exactly the same settings except for the land use and land cover. One simulation referred as control simulation used the satellite-based land use and land cover data of the early 1980s. The other three simulations used the satellite-based land use and land cover data of 2000 only for Northeast, Central and Southeast China. By comparing the seasonal mean temperature of control simulation to ground measurement of 1981-1990, we found that WRF model had a cooling bias of about 2-3 ℃; however, WRF model well reproduced the spatial pattern of seasonal mean temperature with the correlation coefficient of 0.91-0.99 (P < 0.001). By comparing sensitive simulations with control simulation, we found that agriculture development resulted in significant changes of local temperature, but with large spatial differences and seasonal differences. In Northeast and Central China, the conversions from forest and grassland to cropland resulted in a cooling effect and the maximum cooling of about 0.41 ℃ occurred in winter. These land use conversions might enhance surface albedo and thereby reduced the surface net solar radiation; as a result, the surface sensible heat decreased and cooling occurred. In Southeast China, the conversion from forest to cropland led to a warming effect with the maximum being about 0.14 ℃ occurring in summer. The deforestation resulted in a flat surface and, thereby, turbulence was suppressed. Then, due to the suppressed turbulence, surface sensible heat was mostly used to heating bottom air rather than emitting into upper air. As a result, the surface climate warming occurred. The abovementioned cooling and warming effects induced by agriculture development could be comparable locally to the climate background changes. However, these cooling and warming effects had very weak modifications on regional mean temperature. This result implicates that the agriculture development-induced cooling and warming effects merely occurred in the locality and had little impacts on regional temperature changes.

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    Spatial relationship and formation mechanism of geological relics and ethnic cultural resources in western Guangxi, China
    Song HUANG, Yanlin LI, Ruyou LI
    2015, 70 (9):  1434-1448.  doi: 10.11821/dlxb201509007
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    Taking western Guangxi as a typical study area, the paper proposed a universal quantitative study scheme of spatial relationships between geological relics and ethnic cultural resources from the aspects of quantity spatial relationship, quality spatial relationship and spatial coupling relationship. The results show that the quantitative spatial correlation index value R between geological relics and ethnic cultural resources in western Guangxi is 0.478, the close quantity spatial relationship is found to be distinct based on significance testing. The higher the coupling degree value CI is, the closer the quality spatial relationship between geological relics and ethnic cultural resources is; The average CI of western Guangxi is 0.95 to achieve quality level, indicating the close quality spatial relationship; The higher the evaluation value of coupling resources D is, the closer the spatial coupling relationship between geological relics and ethnic cultural resources is. The average D of western Guangxi is 1.04, which indicates a great comprehensive level of the spatial coupling relationship but an unevenly distribution pattern. The D value is high in 12 counties including Jingxi, Pingguo, Nandan and Yizhou, while it is low in counties including Tianlin, Tiandong and Youjiang. The formation mechanism of the close spatial relationship between geological relics and ethnic cultural resources is illuminated by the synchronic and ever-existing interaction and influence of each other in ethnic areas, and geological relics with natural environment form the geography genes that influence and restrict the production, development and evolution of ethnic culture, while ethnic culture is the product that reflects the selection and adaptation of capability of nationalities to varied geological relics with natural environment.

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    Human-Environment Interaction
    Gridding reconstruction of land use pattern in Jiangsu Province in the mid-Qing Dynasty
    Qian PAN, Xiaobin JIN, Yinkang ZHOU
    2015, 70 (9):  1449-1462.  doi: 10.11821/dlxb201509008
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    Reconstructing the spatial data of historical LUCC could fill the gap between modern remote sensing interpretation results and long-term LUCC change analysis, and promote the study of spatiotemporal dynamics of land use and its impacts on climate and ecology. The current studies has obtained certain achievements and revealed the spatial pattern of historical LUCC to some extent. However, the results were normally in the form of single land use type and low spatial resolution. Thus, this study targeted to propose an integrated method of land use reconstruction with relatively high spatial resolution. We set 1820 as the time section and took the administrative boundary of contemporary Jiangsu Province as the study area. Supported by historical documentary records, historical geography research results, modern statistical data and natural environmental data, we divided the land use types into cropland, settlement (including urban land and rural residential land), water body and other lands (including forest, grassland and unused land). Considering the characteristics of regional natural resources and socioeconomic conditions, theoretical hypotheses were proposed to obtain the areas of cropland, urban land and rural residential land at prefectural level. Based on the modern land use pattern, from the perspective of man-land relationship, the land use map of Jiangsu Province in 1820 with a spatial grid of 100 m×100 m was established by administrative seat proximity analysis, integrated suitability indices analysis and so on. Then, statistics of different geographical divisions and comparative analysis of data in sub-regions were used respectively to analyze and validate the results indirectly. The results showed that: (1) In 1820, the area of cropland, urban land, rural residential land, water body and other lands of Jiangsu Province accounted for 48.49%, 4.46%, 0.16%, 15.03% and 31.86% of the total study area respectively. (2) The land use pattern in Jiangsu Province has general features of higher cultivation rate and lower construction rate. Meanwhile, affected by the discrepant population distribution, topography and drainage density, land use in different geographical divisions varied significantly. (3) The proportion of the area of residential land and cropland at county level occupying the correspondent city level in 1820 and 1985 showed a significant positive linear correlation. Therefore, the results of this study had certain reasonability and could provide methodological references for related historical LUCC reconstruction.

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    Identifying contributions of climate change and human activities to spatial-temporal cropland changes: A review
    Xiaoli SHI, Wenjiao SHI
    2015, 70 (9):  1463-1476.  doi: 10.11821/dlxb201509009
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    It is important to study the contributions of climate change and human activities to spatial-temporal changes of cropland in the fields of climate change and land use change. Relationships between spatial-temporal cropland changes and driving forces were studied at qualitative aspects in most of the previous researches. However, the quantitative assessments of the contributions of climate change and human activities to spatial-temporal changes of cropland need to be explored for a better understanding of the dynamics of land use changes. We systematically reviewed the methods of identifying contributions of climate change and human activities to temporal-spatial cropland changes at quantitative aspects, e.g. model analysis, mathematical statistical method, framework analysis, index assessment and difference comparison. The progresses of the previous researches on quantitative evaluation of the contributions were introduced. However, there were four defects in assessing the contributions of climate change and human activities to spatial-temporal cropland changes. For example, the methods were lack of comprehensiveness, and the data need to be more accurate and abundant. Moreover, the scale was single and the explanations were biased. Meanwhile, we concluded a clue about quantitative approaches to assess the contributions from the synthetical aspect to specific driving forces. Besides, the solutions of the future researches on data, scale and explanation were proposed.

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    Orginal Article
    Study of the Cesium-137 Reference Inventory in the Mainland of China
    Wei ZHANG, Shaoming PAN, Kexin ZHANG, Liguo CAO, Jie ZHAO
    2015, 70 (9):  1477.  doi: 10.11821/dlxb201509010
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    Soil erosion is a serious environmental problem closely associated with sustainable development and ultimately the survival of mankind. Cesium-137, a unique artificial radioactive tracer, has been widely applied to the study of soil erosion and deposition since the 1960s. Furthermore, it is a basis for determining a Cesium-137 Reference Inventory (CRI) that employs cesium-137 to measure soil erosion, which can directly influence the accuracy and reliability of the soil erosion rate. This paper references 102 CRI data samples collected from over 80 documents; it also uses the monthly precipitation dataset from the Global Precipitation Climatology Centre from 1981-2010, with spatial resolutions of 2.5°×2.5° and 0.5°×0.5°. The Modified CRI Model for the Mainland of China (MCM) that the paper established is based on incorporating and modifying two previous models, the Walling & He Model (WHM) and the Michio Aoyama Model (MAM). Then we calculate the geographical distributions of CRI by using Kriging/Cokriging interpolation. The model assessment and comparative analysis demonstrate that MCM simulated values are generally in agreement with the observed values and greater than WHM and MAM simulated values. MCM can be applied to higher resolution and higher precision CRI modeling in the Mainland of China. The results show that the range of CRI in the Mainland of China is between 141 and 12123 Bq/m2, and the maximum values are found in parts of northeast China and Xinjiang regions. The minimum values generally come from the regions south of 25°N. Except for some parts of Xinjiang, distributions of CRI in the Mainland of China indicate that CRI increases with precipitation from west to east of the same latitude, while zonal distributions of CRI indicate that CRI increases with the increase of the latitude. Besides, other factors such as large-scale atmospheric flow field, re-suspension, and local nuclear testing contribute to the heterogeneity of CRI in the Mainland of China.

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    Ecology and Environment
    Wavelet multi-resolution analysis of vegetation dynamic change in Dongting Lake Basin
    Yuehong LONG, Jianxin QIN, Xinguang HE, Zhun YANG
    2015, 70 (9):  1491-1502.  doi: 10.11821/dlxb201509011
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    The vegetation dynamic change can be analyzed by applying the discrete wavelet multi-resolution analysis (MRA) to decompose the normalized difference vegetation index (NDVI) time series into subseries at different time scales. In this thesis, the NDVI time series over Dongting Lake Basin was decomposed under different time scales by the wavelet transform. Then the latent seasonal and inter-annual variability of vegetation was mined and assessed. Finally, the possible causes of the changes were analyzed in combination with the land cover change analysis result and the rainfall data. The results show that by using the wavelet multi-resolution analysis, the information related to vegetation dynamics in Dongting Lake Basin can be extracted, which includes the mean of the inter-annual component of NDVI, the minimum level of NDVI, the amplitude of the annual phonological cycle, the timing of the maximum NDVI, the trend in the data series and the magnitude of the land cover change. The information effectively depicts the basin's vegetation dynamics characteristics. Furthermore, with the combination of land cover change analysis result and precipitation data, an obvious correlation was found between the change of vegetation cover and the precipitation change in the basin, that is, the vegetation dynamic changes response to precipitation is the most obvious in the western and northwestern parts of the basin. Although there is no obvious decrease in precipitation in some areas, the vegetation cover has a decreasing trend, which may be related to other factors, such as higher terrain and urbanization.

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    The capacity of soil loss control in the Loess Plateau based on soil erosion control degree
    Haidong GAO, Zhanbin LI, Peng LI, Lianlian JIA, Guoce XU, Zongping REN, Guowei PANG, Binhua ZHAO
    2015, 70 (9):  1503-1515.  doi: 10.11821/dlxb201509012
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    The capacity of soil and water conservation measures, defined as the maximum quantity of suitable soil and water conservation measures contained in a region, were determined for the Loess Plateau based on zones suitable for establishing terraced fields, forestland and grassland with the support of geographic information system (GIS) software. The minimum possible soil erosion modulus and actual soil erosion modulus in 2010 were calculated using the revised universal soil loss equation (RUSLE), and the rate of the minimum possible soil erosion modulus under the soil and water conservation measures to the actual soil erosion modulus was defined as the soil erosion control degree. The control potential of soil erosion and water loss in the Loess Plateau was studied using this concept. Results showed that the actual soil erosion modulus were 3355 t·km-2·a-1, the minimum possible soil erosion modulus was 1921 t·km-2·a-1, and the soil erosion control degree was 0.57 (medium level) on the Loess Plateau in 2010. In terms of zones, the control degree was relatively high in the valley plain zones, soil and rock mountainous zones, and windy sand zones, but relatively low in the soil and rock hilly forest zones, hilly gully zones and plateau gully zones. In terms of river basins, the soil erosion control degree was relatively high in the Dahei River, Huangfu River, Qingshui River, Kuye River and Pianguan River basins, but relatively low in the Qingjian River, Wuding River, Jialu River, and Yanhe River basins. The rate of erosion zones with a soil erosion modulus of less than 1000 t·km-2·a-1 increased from 50.48% to 57.71%, forest and grass coverage rose from 56.74% to 69.15%, ratio of terraced fields increased from 4.36% to 19.03%, and per capita grain yield rose from 418 kg·a-1 to 459 kg·a-1 under the soil and water conservation measures compared with actual conditions.

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    Tectonic uplift of Mt. Lushan indicated by the steepness indices of the river longitudinal profiles
    Nairui WANG, Zhiyong HAN, Xusheng LI, Gang CHEN, Xianyan WANG, Huayu LU
    2015, 70 (9):  1516-1525.  doi: 10.11821/dlxb201509013
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    In this study, we extracted nine river profiles from a 5-m DEM of the Mt. Lushan region. Knickpoints of two types, namely the vertical-step knickpoint and the slope-break knickpoint, are recognized, and are compared with the geological settings to determine their origins. At the same time, we calculated the channel steepness index (ksn) and concavity (θ) of separated parts of these rivers, using the stream-power incision model. The results show that these rivers are almost in a transient state represented by the occurrence of knickpoints. The vertical-step knickpoints are related to inhomogeneous substrates and the slope-break knickpoints are ascribed to the lowering of the base level due to rapid mountain uplift. The parts of the rivers below the slope-break knickpoint have a relatively large ksn, which probably indicates a shift from low rate at early uplift to a later high rate. The steepness index in the south of the mountain is larger than that in the north, which might be induced by different uplift rates or substrates.

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    Main characteristics of geography journals indexed in SCI
    Xin ZHAO
    2015, 70 (9):  1526-1534.  doi: 10.11821/dlxb201509014
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    Based on the 2014 SCI Journal Citation Reports released in June 2015, 46 geography journals are divided into five categories, namely integrated physical geography (8 journals), geomorphology and Quaternary studies (17 journals), geographical information science (10 journals), regional physical geography (7 journals) and ecology and landscape (4 journals). Then some indexes including impact factor and total citations of each category are analyzed. Furthermore, studies on the enhancement of academic influence of these journals covering 2009-2014 are conducted. Meanwhile, we made a statistical analysis of the information concerning the number of published papers, publishing country, publication cycle and publishers. Finally, we examine the relationship among the subject, academic influence, editing and publishing of international geography journals. Some conclusions can be drawn as follows: (1) IEEE J-STARS, INT J DIGIT EARTH and J GEOGR SCI are the top three in terms of the growth of impact factor and total citations. (2) The factors affecting quality of journals include academic level, subject development, journal types, the number of papers published, and native language of authors. (3) A total of 33 journals (or 71.7%) of international physical geography are published in the United Kingdom, the United States and the Netherlands. Most of the 46 geography journals (27 or 58.7%) are published by the world prestigious Springer, Elsevier, Taylor & Francis and Wiley-Blackwell.

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