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Table of Content

    14 March 2015, Volume 70 Issue 3 Previous Issue    Next Issue
    Orginal Article
    PAGES synthesis study on climate changes in Asia over the last 2000 years: Progresses and perspectives
    Quansheng GE, Jingyun ZHENG, Zhixin HAO
    2015, 70 (3):  355-363.  doi: 10.11821/dlxb201503001
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    The established background and goals of the last 2 millennia climate research network, past global changes (PAGES2K) were introduced, and the distinctive significance of Asia2k in PAGES project was expounded. The main research progresses from PAGES-Asia2k working group and contributions of China to the synthetic climate reconstructions of the last 2000 years were also addressed in this paper. In addition, we analyzed the challenge and key issues during the studies on climate reconstructions over Asia, and discussed the research activities in the future work. Asia is an ideal area to conduct synthesis studies on the climate changes for the past 2000 years due to its long history and abundant proxy types with a high time-resolution; however, at present, the related research work is still in its infancy. The recent progresses showed that during the past 1200 years there was a warmer period (830-1220), a colder period (1340-1880), and a rapid warming period (the 20th century). However, the climate of Asia is characterized by various types, complicated process changing and large regional differences. Thus, the future work of this project will focus on the following topics: developing the new methodologies for climate change reconstructions to improve the reliabilities of reconstructed results in individual sites (regions) and the temporal-spatial resolutions, data coverage for the whole continent; developing the PAGES-Asia2k proxy climate database for synthesis study to reconstruct the regional temperature series and spatial patterns of wet and dry changes; furthermore, studying the mechanism and impact of climate change and its adaptation at regional scale.

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    The spatio-temporal change of agricultural hydrothermal conditions in China from 1951 to 2010
    Xiaoju NING, Yaochen QIN, Yaoping CUI, Xu LI, Youmin CHEN
    2015, 70 (3):  364-379.  doi: 10.11821/dlxb201503002
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    Based on the daily observation data of 824 meteorological stations during 1951-2010 released by national meteorological information center, this paper evaluates the change of heat, moisture and winter conditions for crop growth. In this paper, we, taking the average over ten years as a value, analyze the spatial and temporal variations of the agricultural hydrothermal conditions in a 1-km grid. Then we build the regression equations of agricultural hydrothermal conditions to simulate the change trend over years. The main conclusions are summarized as follows. (1) The annual mean temperature, mean temperature in the coldest month and accumulated temperatures of the daily mean temperature ≥0℃ increased significantly for most parts of China, whose contours moved northward in the past 60 years. (2) The mean temperature in the hottest month can be identified into the falling region and rising region, the latter is distributed in Northeast China, Inner Mongolia Plateau and the coast of southeast China. The middle and lower reaches of the Yellow River and the Yangtze River belong to the region in a remarkable reduction. (3) The annual precipitation has an increasing trend, but it is inconspicuous. (4) The contours of 800 mm rainfall and the southern of 400mm rainfall were stable between 1951 and 2010, which determined the distribution pattern of agricultural production of China. However, the mean temperature in the hottest month of the middle and lower reaches of both the Yellow and Yangtze rivers had a decreasing trend from 1951 to 2010, and the contour of mean temperature in the coldest month shifted northward, in particular, the 0℃ contour gradually moved to the yellow line by the region of Qinling-Huaihe River. This had a major impact on the distribution of crops as well as on the farming system. Thus, the complex change of high temperature, low temperature, and heat supply in the crop growing period and water had impact on the agricultural production, which would change due to the regional differences and crop characteristics. We will study the suitable cultivation of crop in the background of global climate change by considering more factors and then explore the adaptability of regional agriculture to climate change.

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    Characteristics of water surplus and deficit change in 10 major river basins in China during 1961-2010
    Ge GAO, Chongyu XU
    2015, 70 (3):  380-391.  doi: 10.11821/dlxb201503003
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    In this paper, linear regression and Mann-Kendall methods are used to examine the climate trend characteristics of annual water surplus and deficit and their causes in the 10 major river basins over China during 1961-2010. The results showed that: (1) The mean annual water surplus and deficit in China during 1961-2010 was negative and the water condition was deficient. The spatial pattern of normal values shows surplus in the south and deficit in the north and west parts of China. (2) The normal monthly values of water surplus and deficit across China show surplus from June to August and deficit in other months. The most surplus was observed in July and the most deficit in April. Different monthly variations were found in each river basin. (3) Decadal variation of annual water surplus and deficit of China shows the feature of more-less-more than normal. The deficit of the 1990s was the least in the past 50 years. In the 2000s, the water deficits of China were more than normal, which was mainly caused by more deficit and less surplus in most of the river basins. (4) Annual, spring, summer and winter water surplus and deficit of China increased during 1961-2010 and the water condition became better, while it decreased significantly in autumn. (5) In the basins of Songhua River, Liaohe River, Haihe River, Yellow River and river basins of Southwest China, the annual water surplus and deficit showed a decreasing trend. For the four major river basins, the decreasing rate of annual precipitation was greater than that of annual potential evapotranspiration, and the decreasing annual precipitation played a great role in these regions. But in river basins of Southwest China, the increasing rate of annual precipitation was less than that of annual potential evapotranspiration, which led to a reduction of water availability. In the Huaihe and Yangtze river basins, the decreasing rate of annual evapotranspiration was greater than that of annual precipitation, which resulted in an uptrend of annual water surplus and deficit. In river basins of Southeast China, Pearl River Basin and river basins of Northwest China, the increase in annual precipitation and decrease in annual evapotranspiration are both beneficial to water increase.

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    Comprehensive evaluation of precipitation heterogeneity in China
    Yonglin LIU, Junping YAN, Minyi CEN
    2015, 70 (3):  392-406.  doi: 10.11821/dlxb201503004
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    Through comparisons of various methods, the method of precipitation concentration degree (PCD) was used to study precipitation heterogeneity. In addition to PCD, normal distribution functions, cumulative frequencies, and percentiles were used to establish a graded evaluation index of precipitation heterogeneity. A comprehensive evaluation of precipitation heterogeneity and its spatiotemporal variation in China in 1960-2013 were analyzed. Results indicated that: (1) seven categories of precipitation heterogeneity could be identified: high centralization, moderate centralization, mild centralization, normal, mild dispersion, moderate dispersion, and high dispersion; (2) during the study period, the precipitation in more parts of China tended to be normal or dispersed, which is beneficial to human activities.

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    Implication of the heating effect of the Tibetan Plateau for mountain altitudinal belts
    Yonghui YAO, Mei XU, Baiping ZHANG
    2015, 70 (3):  407-419.  doi: 10.11821/dlxb201503005
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    The immense and towering Tibetan Plateau (TP) acts as a heating source and shapes the climate of both the Eurasian continent and the entire world. The heating effect of the TP was first noticed by meteorological scientists in the 1950s due to the important implications of the plateau for Asian climate. Most researches focused on its role as the heat source in summer and its implications for Asian climate, but little has been done on the quantitative information about the heating effect of the plateau and its implications for the position of mountain altitudinal belts (MABs). Using estimated air temperature data, observed meteorological data, MAB / treeline data and ASTER GDEM data, this paper compares the position / height of MABs and alpine treelines between the main TP and the surrounding mountains / lowland and explains the spatial pattern of MAB / treeline of TP from the point of view of the heating effect. The results demonstrate the following important characteristics. (1) Due to the heating effect of TP, the air temperatures and the length of growing season gradually increase from the eastern edge to the interior main TP. The monthly mean air temperature in the interior main plateau is approximately 2-7 ℃ higher than that in the surrounding mountains and adjacent lowland areas. At an elevation of 4500 m (corresponding to the mean altitude of the TP), the monthly mean temperature differences between the plateau and the Sichuan Basin range from 3.58 °C (April) to 6.63 °C (June); the height of the 10°C isotherm of the warmest month goes upward from the edge to the interior of the plateau, which is 4000 m in the Qilian Mts. and its eastern edges, while uplifts to 4600-5000 m are observed along the belt of Lhasa- Zuogong; the warmth index at the altitude of 4500 m in the interior main TP can reach 15°C / month, but it is lower than 15°C / month on the eastern edges and the northern parts of the TP. (2) In terms of air temperatures, the height of the 10°C isotherm of the warmest month and the warmth index gradually increase from the easternmost to the interior of the main plateau; MABs and treeline follow a similar trend rising inwards, the dark-coniferous forest is distributed at an altitude of 1000-1500m higher in the interior main plateau than on the eastern edges, and the alpine steppe belts are about 700-900 m higher in the interior main plateau than on the eastern edges.

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    Correlation analysis of rainfall and ENSO in Shanxi
    Fen LI, Jianxin ZHANG, Zhiwen HAO, Yongli WU, Jinhong ZHOU
    2015, 70 (3):  420-430.  doi: 10.11821/dlxb201503006
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    Based on the monthly rainfall data, the CPC (Climate Prediction Center) Southern Oscillation Index (SOI) and the monthly Pacific SST (Sea Surface Temperature) of NOAA (The National Oceanic and Atmospheric Administration) at 38 meteorological stations in Shanxi, trend analysis and correlation analysis methods were used to analyze the response of the seasonal rainfall during recent 56 years to ENSO events in this province. The results are shown as follows: (1) In La Nina years, the annual, autumn and winter rainfall had increasing trends, while the spring and summer rainfall decreased. In El Nino years, the spring rainfall had increasing trends, but the annual, summer, autumn and winter rainfall decreased. In the year after a La Nina event, the winter rainfall would increase, but the annual, spring, summer and autumn rainfall decreased. (2) The annual rainfall showed that there was a positive correlation between Pacific SST of the previous year in Nino 3 and 4 regions and annual rainfall in Shanxi. If Pacific SST of the previous year was higher (or lower), the rainfall in Shanxi would be correspondingly more (or less) than that in a normal year. The annual rainfall was negatively correlated to Pacific SST of the same year in Nino 3 region. If Pacific SST of a year is higher (or lower), the annual rainfall in Shanxi would be less (or more) than that in a normal year. (3) SOI was significantly and negatively correlated to the rainfall trend index of most parts of Shanxi province. The correlation coefficients in some parts of the central-western and eastern-northern Shanx were over -0.5, and the monthly rainfall of these areas would be less (or more) if SOI was positive (or negative).

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    Origination, study progress and prospect of karst tiankeng research in China
    Wei SHUI, Yiping CHEN, Yawen WANG, Zheng'an SU, Su ZHANG
    2015, 70 (3):  431-446.  doi: 10.11821/dlxb201503007
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    Karst tiankeng, which was discovered in peak cluster and hoodoo karst areas of southern China at the end of the 20th century, is a very special and grand negative karst landform. Karst tiankeng in China has been paid more attention by geomorphologists and geologists all over the world since it was discovered to have its unique values in aspects of scientific research, world natural heritage sites and global geological heritage and tourism. Until now, according to classification method of morphology, geomorphogeny and geomorphic evolution, it has been disputed for a long time whether karst tiankeng can be significantly distinguished from normal dolines. Additionally, the understanding of the classification, geomorphic evolution, developmental conditions, geological dating, and karst ecological environment of tiankeng are still extensively disputed by geomorphologists and geologists.Meanwhile, a growing recognition of the values and the development and protection methods has been received all over the world. This paper reviews the research stages and present progress, as well as the values and the development and protection methods of karst tiankeng in China. Finally, we point out some questions in the studies of karst tiankeng in China and research directions to be paid more attention in the further studies.

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    Progress in anthropogenic geomorphology
    Jialin LI, Lei YANG, Xiaoping YANG
    2015, 70 (3):  447-460.  doi: 10.11821/dlxb201503008
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    With the improving capabilities of human beings in remaking the nature, human activity has become the third morphotectonic force during the modern geomorphological process. The effect of human activities on original geomorphological features of earth surface is extremely obvious, in some aspects, the energy level of its remarking forces in earth environment even surpasses that of natural forces. Accordingly various man-made landforms generate from different natural geomorphological structures. Man-made landform is a humanistic-featured landform shaped by the coordinated morphotectonic forces from human and nature within a certain natural geographical background. This paper first summarizes main research progress of man-made geomorphology from the following aspects, namely, the origin of anthropogenic geomorphology, man-made landform agents and geomorphology categorization, the evolution of man-made landforms and its influencing mechanism, map presentation of man-made landforms and the effects of man-made landforms on the environment. After that, this paper pointed out that man-made geomorphology has attracted much attention from researchers, however, many problems on the object, content, methodology and theoretical system in current studies need to be solved. The study of man-made geomorphology should refer to research achievements in relevant subjects and modern geo-information techniques, so as to raise our cognitive levels and examine the vitality, characteristics and scientific meanings of this discipline. Finally, this study forecasted the progress of man-made geomorphology, and argued that future study in anthropogenic geomorphology should strengthen the construction in the disciplinary system of anthropogenic geomorphology, constituent materials and morphologic characteristics, spatial expansion process and the evolution laws, regional variations and accumulative environment effects from man-made landform, environment management and international comparative study of man-made landforms, which will promote the development of anthropogenic geomorphology and the process of man-made landforms in modern social and economic constructions.

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    LUCC simulation based on the cellular automata simulation: A case study of Dalian Economic and Technological Development Zone
    Jun YANG, Peng XIE, Jianchao XI, Quansheng GE, Xueming LI, Zhandong MA
    2015, 70 (3):  461-475.  doi: 10.11821/dlxb201503009
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    China has been experiencing the exceptionally drastic land-use/cover changes (LUCC) in the last decades. Many techniques focused on the simulation of the single type of land-use change. However, simulating changes between different types of land-use is much more difficult than simulating change for a single type of land-use. The key to simulations based on the Cellular Automata (CA) model is how to define the transition rules. This paper built a localized land-use competition CA model to examine land-use change rules for several land-use candidates under different localized land-use patterns. By this method, the potential transformation amount of each land-use type was calculated and an optimum transition rule was used to balance the amount of land-use changes of complicated types during the simulation period. The total area of each land-use type was predicted by Markov analysis as the global variable during the whole simulation period. This CA-Markov method was adopted to simulate LUCC in Dalian Economic and Technological Development Zone in 1998 and 2009, followed by a comparative experiment. The results show that: (1) The established test method is feasible for exploring the interaction between various land-use classes; (2) This model had high simulation precision, and the Kappa coefficients in urban area, agricultural area and undeveloped area were 0.762, 0.634 and 0.678, respectively; (3) The model proposed in this paper shows a symbolic way to studying the conversion among different land-use types, which could be used to improve the interactive relationship of LUCC.

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    Land ecological suitability assessment for forest coupled with the resilience perspective: A case study in Wangqing county, Jilin province, China
    Yanxu LIU, Yanglin WANG, Jian PENG, Hai WEI, Zhiqing SONG, Xiaofei ZHANG
    2015, 70 (3):  476-487.  doi: 10.11821/dlxb201503010
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    This article tries to examine the changing trend and sustainability of vegetation according to the resilience concept. Then it analyzes the wood land habitats in a typical forest county from a temporal-spatial perspective. Moreover, artificial neural network, trend analysis, partial correlation analysis and R/S analysis were adopted to respectively evaluate the habitat quality, the change of vegetation, the driving force and the judgment of trend dependence. The result shows that there exists good ecological suitability on watershed level. The low ecological suitable region is in the habitat with a poor natural background and intense human activity, while the high ecological suitable region has good ecological conditions in the habitats and the sustainable ability in ecological resilience. This study uses Hurst index to judge the persistence as the spatial expression of resilience. In this concept system, the resilience perspective can be applied in specific regional forestry management. Compared with the subjective evaluations, the mathematical measurement methods used in this article, such as neural network clustering of SOFM, the trend analysis of Theil-Sen Median, and the significance test of Mann-Kendall, can effectively reduce the uncertainty.

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    Impact of joint operation of reservoirs on the change ratio of downstream cross-sectional geometry parameters: A case study of the Inner Mongolian reach of the Yellow River
    Teng SU, Suiji WANG, Yanguo MEI
    2015, 70 (3):  488-500.  doi: 10.11821/dlxb201503011
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    Studies of the impacts of reservoir operation on downstream channel changes have been a hot spot in fluvial geomorphology in the last decades. However, it remains unknown on how to quantitatively express channel adjustments induced by the joint operation of upstream reservoir systems. The joint operation of the Liujiaxia and Longyangxia reservoirs on the upper Yellow River since 1986 has significantly influenced downstream channel variations. The objective of the paper is to analyze the channel cross-section changes at Dengkou, Bayangaole, Sanhuhekou, and Toudaoguai gauge stations located in the Inner Mongolian reach of the upper Yellow River in the period 1978-1982 (the earlier period, before the joint operation) and the period 2008-2012 (the later period, after the joint operation). As for the four gauge stations, we calculated the change ratios of cross-sectional geometry parameters, including channel cross-section area, water width, mean water depth, and the ratio of width to depth, at a given water level after the flooding season. The results show that most of the change ratios of the geometry parameters increased remarkably after the flooding season. Furthermore, the change ratio of each parameter at all the channel cross-sections decreased significantly in the later period compared with that during the earlier period. The change ratio of the cross-section area decreased 3.4 times while that of the water width and mean water depth decreased 3.5 times and 2.8 times, respectively. Spatially, the downstream variations of the change ratio of the geometry parameters evolved from a convex curve in the earlier period to an "S"-shaped curve in the later period. The observed decreases of the change ratios of channel geometry parameters are due to the joint operation of large upstream reservoirs. These reservoirs stored a large amount of flood water and reduced the peak discharge and maximum flow velocity in the flooding season; as a result, the erosion ability of the floods decreased. With the joint operation of the large reservoirs, the Inner Mongolian reach of the Yellow River shrunk significantly in recent years and the channel is faced with a great risk of extreme floods. Therefore, it is necessary to reasonably utilize the dam's adjustment functions for a better control of runoff and sediment export in the flooding season. With effective measures taken, the channel can avoid further shrinkage and is thus ready for extreme floods.

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    Water consumption in Inner Mongolian reach of the Yellow River since integrated water regulation
    Shuangyan JIN, Suiye ZHANG, Zhijin MA, Ping ZHANG
    2015, 70 (3):  501-508.  doi: 10.11821/dlxb201503012
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    The integrated water regulation of the Yellow River was initiated in March 1999. This paper analyzed the annual allocation, inter-annual variance and relation of water diversion and recession in Inner Mongolian reach of the Yellow River main stream from 1999 to 2011. Water diversion and recession gates from Shizuishan to Toudaoguai reach of the Yellow River were verified with the aid of remote sensing images. Water consumption of Inner Mongolian reach is calculated by both the water diversion-recession method and the water balance method. The results indicated that the mean ratio of water recession and water diversion in the Hetao Irrigation District of Inner Mongolia Autonomous Region is 0.16 with a year-on-year increase. The correlation between water recession and diversion in this district is good, i.e. larger water diversion is companied with larger water recession. The average water consumption calculated through the water diversion-recession method is 7.544 billion m3 and the inter-annual variance is relatively steady, while the result obtained through the water balance method is 5.672 billion m3 and the inter-annual variation is obvious. The difference of the results by these two methods is remarkable. One of the important reasons for causing the difference is the discrepancy between the numbers of the certified water gates and actual water gates.

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