Table of Content

20 July 2011, Volume 66 Issue 7 Previous Issue    Next Issue

Comparison between Quaternary Glaciations in China and the Marine Oxygen Isotope Stage (MIS): An Improved Schema ZHAO Jingdong, SHI Yafeng, WANG Jie 2011, 66 (7):  867-884.  doi: 10.11821/xb201107001 Abstract ( )   PDF (887KB) ( )   Save In the past two decades, dating techniques, including cosmogenic radionuclide (CRN) or terrestrial in situ cosmogenic nuclides (TCN), optically stimulated luminescence (OSL), electron spin resonance (ESR), which can potentially and directly determine the ages of glacial landforms and sediments have been refined and widely applied. These techniques in combination with other dating methods, such as lichenometry, 14C and thermoluminescence (TL) dating, have promoted further understanding of Quaternary glaciations in China, and some new progress has been achieved. For example, abundant dating data, which are consistent with the stratigraphy and geomorphology have been determined; glacial sequences constrained by numerical ages in the Qinghai-Xizang Plateau and bordering mountains have been obtained; the coupling relationship between the uplift of the Qinghai-Xizang Plateau and the glacier evolution in Quaternary has been identified. An improved comparative schema between Quaternary glaciations and marine oxygen isotope stage (MIS) has been proposed on the basis of the available data. The improved comparative schema includes 15 special stages and sub-stages during the last 1 million years. Information, such as time (ka), MIS, Chinese glaciations are accessible. The authors expect more comments and suggestions on the improved schema. References | Related Articles | Metrics

Climatic Change in Cold and Warm Winter over Tibet during 1961-2010 DU Jun, YANG Zhigang, SHI Lei, MAPengfei 2011, 66 (7):  885-894.  doi: 10.11821/xb201107002 Abstract ( )   PDF (782KB) ( )   Save According to the China national standard, the warm winter is classified into two groups by space and intensity grades. In the space group the warm winter is divided into two spatial grades as single station warm winter, and regional warm winter. In the intensity group, there are two grades as weak warm winter (warm winter) and strong warm winter. Average winter air temperature is divided into three probability categories to define the threshold of warm winter for single station and its warm winter intensity. Then the division criteria for regional winter warm intensity are calculated according to percentile rank of warm winter stations. In accordance with this standard, the grade of single station and regional cold winter are determined. On the basis of the division method for cold and warm winter, the characteristics of cold and warm winter from 1961 to 2010 over Tibet are analyzed. The results show that the mean temperature in winter has increased over Tibet with a rate of (0.29-1.04) oC/10a in recent half century, and the maximum value is in Bangoin. Especially in recent 20 years (1991-2010), the warming amplitude becomes stronger with a rate of (0.73-2.36) oC/10a. Regional warm winter index has an obvious rising trend at a decadal rate of 16%, which is higher than that in Northeast China, North China and Northwest China. Frequency of single station warm winter is 32%-52% with 6%-26% of strong warm winters. There are 21 regional warm winter years over the 50 years with 10 strong warm winters, and there are more occurrences of warm winter in the 2000s, while the most extensive and strongest of regional warm winter occurred in 2006 and 2009. The results also show that the frequency of single station cold winter is 18%-40% with 2%-20% of strong cold winters, and that regional cold winter index has a decreasing trend at a decadal rate of 12%. There are 16 regional cold winter years over the 50 years with 8 strong cold winters, and more occurrences of cold winter was observed in the 1960s. Additionally, the year 1962 witnessed the most extensive and strongest regional cold winter, followed by 1968 and 1983. References | Related Articles | Metrics

Expansion of Glacial Lakes and Its Implication for Climate Changes in the Chinese Himalaya WANG Xin, LIU Shiyin, MO Hongwei, YAO Xiaojun, JIANG Zongli, GUOWanqin 2011, 66 (7):  895-904.  doi: 10.11821/xb201107003 Abstract ( )   PDF (900KB) ( )   Save The Himalayas has drawn a wide attention in the context of the changing climate. The expansion of glacial lakes shows the variation of climate changes and is of importance to understand the risks of glacial lake outburst flood. On the basis of large scale topographical maps, DEMs, ASTER, images, glacial lake area variation against elevation and the changes of distance between glacial lake and its parent glacier were analyzed and the climatic implications were discussed in the Chinese Himalaya. The results show that, in the past 30 years, (1) the survived glacial lake expansion was a dominant contributor to the increase of glacial lake area, accounting for about 67%, and new formed lakes contributed to the rest 33% of area increment; (2) glacial lake area was averagely increasing in all 100-m-elevation bands where the largest growth occurred at elevations of 5000-5300 m, indicating a vertical variety of climate changes; (3) the more closer the glacial lake is to its parent glacier, the greater the area increasing rate of the glacial lakes, and among 15 types of glacial lake-glacier distance variation, 60% of net lake area increment was due to the lakes directly connected with parent glaciers in the 2000s in Chinese Himalaya. References | Related Articles | Metrics

Spatial Distribution and Temporal Trends in Potential Evaporation over Hengduan Mountains Region from 1960 to 2009 ZHU Guofeng, HE Yuanqing, PU Tao, LI Zongxing, WANG Xufeng, JIAWenxiong, XIN Huijuan 2011, 66 (7):  905-916.  doi: 10.11821/xb201107004 Abstract ( )   PDF (1084KB) ( )   Save In this paper, annual and seasonal changes of potential evaporation were analyzed to conduct studies on hydrological model and ecological environment based on climate data at 20 meteorological stations in the Hengduan Mountains region during 1960-2009, in combination of the Penman-Monteith model. The changing trend in potential evaporation over the Hengduan Mountains is analyzed in this study. With the method of Spline under ArcGIS, the spatial distribution of potential evaporation is presented to research the regional difference. And the correlation analysis is used to discuss the dominant factor affecting the potential evaporation. The results indicate that the annual potential evaporation showed a decreasing tendency since the 1960s, especially from the 1980s to the 1990s, while it showed an increasing tendency since 2000. Regional potential evaporation showed a rate of -0.17 mm a-1. The potential evaporation in north, middle and south of Hengduan Mountains exhibited decreasing trends over the studied period, and its regional trend was on the decline from the southwest to the northeast. References | Related Articles | Metrics

MODIS-based Air Temperature Estimation in the Hengduan Mountains and Its Spatio-temporal Analysis YAO Yonghui, ZHANG Baiping, HAN Fang 2011, 66 (7):  917-927.  doi: 10.11821/xb201107005 Abstract ( )   PDF (1061KB) ( )   Save Climatic conditions are difficult to obtain in high mountain areas due to few meteorological stations and, if any, their poorly representative locations in valleys. Fortunately, remote sensing data can be used to estimate near-surface air temperature (Ta) and other climatic conditions. This paper makes use of recorded meteorological data and MODIS data on land surface temperature (Ts) to estimate monthly mean air temperatures in the Hengduan Mountains. A total of 64 weather stations and 84 MODIS images for seven years (2001 to 2007) are used for analysis. Regression analysis and spatio-temporal analysis of monthly mean Ts vs. monthly mean Ta are carried out, showing that recorded Ta is closely related to MODIS Ts in the study region (mean R2 = 0.72) and the mean standard error of 2.07 oC. The regression analysis of monthly mean Ts vs. Ta for every month of all the stations shows that monthly mean Ts can be used to accurately estimate monthly mean Ta (R2 ranging from 0.63 to 0.90 and standard error between 2.22 oC and 3.05 oC). Thirdly, the retrieved monthly mean Ta for the whole study region varies between -2.25 oC (in January, the coldest month) and 15.64 oC (in July, the warmest month), and for the warm (growing) season (May-September), it is from 10.44 oC to 15.64 oC. Finally, the elevation of isotherms is greater in the central mountain ranges than that in the outer margins; the 0 oC isotherm occurs at elevations of about 4700±500 m in October, and it drops to 3500±500 m in January, and ascends back to 4700±500 m in May next year, which means that monthly mean Ta in the areas below 5200 m is above 0 oC for 6 to 12 months. This clearly indicates that MODIS data could be used to have an accurate estimation of air temperature in mountain regions. References | Related Articles | Metrics

Responses of Cropland Phenophases to Agricultural Thermal Resources Change in Northeast China LI Zhengguo, TANG Huajun, YANG Peng, ZHOU Qingbo, WUWenbin, ZOU Jinqiu, ZHANG Li, CHANG Hsiaofei 2011, 66 (7):  928-939.  doi: 10.11821/xb201107006 Abstract ( )   PDF (880KB) ( )   Save In this study, by using the SPOT/VGT NDVI ten-day composed time-series data, observed crop phenophases and climate data collected from 1998 to 2010, we investigate the responses of cropland phenophases to agricultural thermal resources change in Northeast China. Firstly, the seasonality parameters, such as the start date, the end date, the peak date and length of the growing season, were extracted from the smoothed NVDI time-series dataset and showed a close correlation with the observed crop phenophases; Secondly, the spatio-temporal trends of the major agricultural thermal resources in Northeast China were illustrated and analyzed over the past 20 years; Thirdly, we focus on the responses of cropland phenophases to agricultural thermal resources change. The results show that the start date of growing season has a significant positive correlation with the first date of the temperature ≥ 10 oC (P < 0.01), especially in the northern part of Songnen Plain, eastern part of Sanjiang Plain and central-eastern part of Jilin Province. As for extracted length of growing season and observed days of growing period, significant correlations can be found in the same regions. However, notability check shows that there are no significant correlations between the end date and the first frost date in the study area. Opposite correlations are observed between the length of growing season and the accumulated temperature ≥10 oC. In the northern part of Songnen Plain, eastern part of Sanjiang Plain and central part of Jilin and Liaoning provinces, positive correlation coefficients are higher than the critical value of the level of 0.05, while negative correlation coefficients reach the level of 0.55 in central-southern part of Heilongjiang Province and some parts of Sanjiang Plain. References | Related Articles | Metrics

Soil Loss Tolerance for Black Soil Species in Northeast China XIE Yun, DUAN Xingwu, LIU Baoyuan, LIU Gang, FENG Yanjie, Gao Xiaofei 2011, 66 (7):  940-952.  doi: 10.11821/xb201107007 Abstract ( )   PDF (971KB) ( )   Save Soil Loss Tolerance (T) is a quantitative criterion for soil conservation, and it is determined empirically at present due to limited quantitative researches. The black soil region of Northeast China, one of the major grain production bases in China, was selected as the study area. Soil depths were investigated and physicochemical properties of soil profiles were analyzed for 21 black soil species in the study area. T values of the 21 black soil species, calculated by using a modified productivity index model, varied from 68 t/km2×a to 358 t/km2×a, and 141 t/km2 × a in average, and 106 t/km2 × a for albic black soils (Albic Stagni-Udic Isohumosols), 129 t/km2 × a for black soils (Hapli-Udic Isohumosols), and 184 t/km2 × a for meadow black soils (Mottlic Hapli-Udic Isohumosols). Soil depths and soil erosion vulnerability index were two key factors influencing T values. The correlation coefficients of these two factors with T were 0.750 and 0.605 repectively. The meadow black soils had the largest soil depth and similar erosion vulnerability index close to that of black soils, and its T value was 42.6% larger than that of black soils. The soil depth of Albic black soils was 22.1% larger than that of black soils, and its T value was 21.7% smaller than that of black soils. This is due to the existence of obstacle horizon for Albic black soils. Therefore, determination of T values for different soil species or families is more practical for soil conservation in terms of soil profile properties. References | Related Articles | Metrics

A Comprehensive Assessment Method of Hydropower Development Impact on Runoff and Sediment Change LIU Xinyou, HE Daming 2011, 66 (7):  953-960.  doi: 10.11821/xb201107008 Abstract ( )   PDF (729KB) ( )   Save The rivers in Southwest China are the major base for large-scale hydropower development, and its change and responses of sediment and runoff are quite complicated. The assessment of the change and response has been the focus topics for the cascade hydropower dams building. In this paper, the Lancang River, which has 25 years' large-scale hydropower development, was chosen as a study case for establishing the affected evaluation indexes system of runoff and sediment and the reduction model of indexes, determining the indexes weight by AHP and factor analysis method, and setting up the indexes affected level evaluation models using the "marginal efficiency" principle. After the assessment of runoff and sediment change under the cascade development in Lancang River based on these methods and the model mentioned above, the results are obtained as follows. (1) During the 30 years of the hydropower development from 1986 to 2007, the impact of sediment transport affected by the cascade development is much greater than that of runoff change; 72.7% of the years with "very low" impact level of sediment transport change, 18.2% with "low" level, and 9.1% with "average" level. (2) The change process of runoff and sediment level affected presents a "U"-shaped pattern of "high-low-high" under the disturbing Manwan dam running and Dachaoshan dam building, which indicates a balance of sediment change due to the joint effect resulting from sediment reduction by Manwan reservoir and sediment increase by the Dachaoshan dam building. References | Related Articles | Metrics

Using ISA to Analyze the Spatial Pattern of Urban Land Cover Change: A Case Study in Shenzhen LIU Zhenhuan, WANG Yanglin, PENG Jian, XIE Miaomiao, LI You 2011, 66 (7):  961-971.  doi: 10.11821/xb201107009 Abstract ( )   PDF (972KB) ( )   Save Based on land cover classification data, there are two key problems that has been often overlooked when we use indices method to analyze the landscape pattern of land cover in rapid urbanization areas. One is mixed pixel involved in the classification process, which has impact on classification accuracy and the final conclusion of landscape pattern analysis. The other is that it is difficult for landscape pattern indices method to detect the change in a pixel and local urban areas, which can only explain the macro regional patterns of urbanization. To solve these problems, based on continuous data, Linear Spectral Method Analysis (LSMA) is used to acquire the index of Impervious Surface Area (ISA) in this case study, considering impervious surface component as the main landscape in urban areas. Thus, we can effectively analyze the spatial pattern and expansion processes of urbanization. Taking Shenzhen as a study area, spatial autocorrelation, semi-variance function and other geo-statistical methods are used to reveal the macro spatial-temporal patterns of a continuous landscape change, and fractal dimension and profile methods are also used to analyze urban landscape along the change direction of location. The results indicated that the continuous landscape metrics and geostatistical methods can help us to understand the spatial and temporal changes of urbanization at regional and local levels, since land cover change, especially in rapid urbanization areas, has a significant gradient characteristic and spatial continuity. References | Related Articles | Metrics

A Model for Regional Land Use Optimization Allocation Based on Multi-agent System and Its Application ZHANG Honghui, ZENG Yongnian, TAN Rong, LIU Huimin 2011, 66 (7):  972-984.  doi: 10.11821/xb201107010 Abstract ( )   PDF (813KB) ( )   Save Land use optimization allocation is one of the important aspects of sustainable regional land use. However, the current prevalent land use optimization allocation model, which is used for directing a sustainable land use system, needs to be improved, because the current models ignore the collaborative optimization of land uses in terms of quantitative structure, spatial pattern, and benefit. The objective of this paper is to establish a new model to solve the shortcomings, i.e., the RLUOA (Regional Land Use Optimization Allocation) model, which aims to achieve regional sustainable land use. The model is established through a multi-agent system, which defines respectively the decision making rules of the related agents including the central government of the region, the branches of the government that implements the downstream orders, and the land users practically using the land. The RLUOA model was applied to the simulation of land use optimization allocation in Changsha, a typical city located in central China. The simulation result shows that the model can reasonably allocate the land into different spatial units under the constraint of multi-objective, and achieve the collaborative optimization of land use in terms of quantitative structure, spatial pattern, and benefit. The resulted optimal land allocation meets the requirements of building economically feasible, socially acceptable, and environment-friendly land use pattern, and improves obviously the overall economic, ecological and social benefits of the land use in the region. Consequently, the model can provide auxiliary support and scientific references for the decision making associated with sustainable regional land use and for the general land use planning design. References | Related Articles | Metrics

The Process of Land Cultivation Based on Settlement Names in Jilin Province in the Past 300 Years ZENG Zaozao, FANG Xiuqi, YE Yu 2011, 66 (7):  985-993.  doi: 10.11821/xb201107011 Abstract ( )   PDF (824KB) ( )   Save Settlements, as a land-use type, can reflect the interaction between human activities and natural environment. In a new cultivation area, establishment of new settlements and agricultural land cultivation were carried out simultaneously, which made it possible to identify the process of land cultivation through studying the temporal and spatial growth of settlements. Settlement names, which recorded the actual situation when people migrated to a new cultivated area, have very important values in research on land exploitation and historical process of land use/cover change. Based on the chorography of toponym in Jilin, this paper studied settlement names according to different types of land cultivation, and developed a method of classification for land cultivation-settlements. Then it identified two types of land cultivation-settlement, which were governmental cultivation-settlements and individual cultivation-settlements. Furthermore the latter could also be divided into two sub-types, individual migration-settlements and governmental recruitment-settlements. In this paper, the process of temporal-spatial distribution of land cultivation in Jilin Province in the past 300 years has been recognized, which may be helpful to study the land use/cover change in Jilin, and also provide an attempt to conduct research on land cultivation based on toponym, or settlement names. References | Related Articles | Metrics

Accuracy Validation of TRMM 3B43 Data in Lancang River Basin ZENG Hongwei, LI Lijuan 2011, 66 (7):  994-1004.  doi: 10.11821/xb201107012 Abstract ( )   PDF (1297KB) ( )   Save The Lancang river basin is a typical area of lacking data with complicated terrain and climate characteristics. It is located in the upper reaches of Mekong river basin. There is great potential to carry out hydrological prediction in ungauged basins by using satellite estimate precipitation data. As a precipitation radar satellite, TRMM has been collecting plentiful fine temporal-spatial precipitation data, so it is significant to use the TRMM precipitation data to study hydrological and climatic characteristics in the Lancang river basin. However, it is necessary to check the accuracy of TRMM data before using it. Based on the correlation coefficients and scatter points slope methods, the accuracy of TRMM 3B43 data at monthly time scale during 1998-2009 was validated by using the 35 rain gauges data, which were distributed in the Lancang river basin and its surrounding areas. Then the influence of slope and elevation on the checking result based on Thiessen polygons and K-Means cluster methods was analyzed. Finally, principal component analysis was used to compare the differences of elevation and slope on the accuracy of TRMM 3B43. The results are obtained as follows. (1) Compared with the 35 rain gauges, TRMM 3B43 data displayed good accuracy in the whole study area at monthly time scale. (2) There were significant differences of accuracy among the 35 sites; the TRMM 3B43 data had good accuracy in the upstream and downstream of the research areas, while the middle area was poor, especially Bomi, Gongshan, Deqin and Shangrila. (3) Compared with slope, the influence of elevation on the accuracy of TRMM 3B43 was more complicated, and the accuracy showed that there was a high-low-high variation when the elevation decreased from upstream to downstream, which may be caused by strong spatial heterogeneity of precipitation in this area. (4) The slope of research area had great influence on the accuracy of TRMM 3B43 data, which decreased as the increase of slope, the middle research area has the maximum slope so the accuracy was the worst, while the upstream and downstream had relatively high accuracy due to flat terrain. References | Related Articles | Metrics