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  • 2001 Volume 56 Issue 4
    Published: 15 July 2001
      
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  • Simulations of Carbon Exchange Between Global Terrestrial Ecosystem and the Atmosphere
    LI Yin peng, JI Jin jun
    2001, 56(4): 379-389. https://doi.org/10.11821/xb200104001
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    In this paper the NPP of global terrestrial ecosystem is estimated by an Atmosphere Vegetation Interaction Model (AVIM). AVIM consists of two intercoupled components: physical processes, involving water and energy transfer among soil, vegetation and the atmosphere at the land surface and eco physiological processes, i.e., photosynthesis, respiration, dry matter allocation, littering and phenology. Globally vegetation is classified into 13 types and soil texture is classified into 6 types, and parameters of eco physiological processes for each vegetation type for AVIM are collected. Daily weather data for 0.5?0.5 grid cells as the forcing of model are generated from monthly climate data. The estimated NPP for different vegetation types at 19 sites are validated with the observed. Three time steps are used for different processes in the model: 30 minutes for physical processes, one hour for physiological processes, and one day for biomass accumulation of tissues. The main results of NPP estimation show that global averaged NPP is 405.13 g C m 2 yr 1, varying from 99.58 g C m 2 y 1 (tundra) to 996.2 gm 2 yr 1 (rainforest). Global total annual NPP is about 60.72 Gt C yr 1, in which the maximum part, about 15 84 Gt C yr 1, or 26.09% of the total, is contributed by tropical rainforest.
  • Simulation Analyses of Terrestrial Carbon Cycle Balance Model in Northeast China
    WANG Shao qiang, ZHOU Cheng hu, LIU Ji yuan, LI Ke rang, YANG Xiao mei
    2001, 56(4): 390-400. https://doi.org/10.11821/xb200104002
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    We have estimated vegetation carbon and soil organic carbon based on the fourth national forest inventory with 121 plots and second national soil survey with 388 soil profiles. Our estimate indicates that the amount of vegetation and soil organic carbon for Northeast China are 2.81×10 15 gC and 26.43×10 15 gC respectively, and that the densities of vegetation and soil organic carbon are 2.27 kgC/m 2 and 21.27 kgC/m 2 respectively. The eastern and northern parts of the region have much higher carbon storage than the rest of the region. Meanwhile, based on climate material, the simplified Terrestrial Carbon Cycle Balance (TCCB) model was established,which is semi mechanism and semi statistics. Through the TCCB model, this paper calculated the litter carbon pool, NPP, carbon fluxes and described the spatial characters of carbon pools and fluxes in Northeast China. Based on the TCCB model simulation, under current climate conditions, NPP in Northeast China is 5.16×10 8 tC/a, vegetation litterfall rate is 5.16×10 8 tC/a, litter mineralization rate is 3.61×10 8 tC/a, soil organic inputting rate is 1.55×10 8 tC/a, the litter carbon pool is 4.67×10 8 tC, and the soil decomposition rate is 1.55×10 8 tC/a. The carbon budget was also analyzed based on the estimates of carbon pools and fluxes. The spatial distribution of carbon pools and carbon fluxes in different compartments of terrestrial ecosystem was depicted with map respectively in Northeast China.
  • Ecosystem Productivity Regionalization of China
    XU Ji tian, CHEN Bai ming, ZHANG Xue qin
    2001, 56(4): 401-408. https://doi.org/10.11821/xb200104003
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    The regionalization of ecosystem productivity in China is the process and result of dividing China into different regions according to the difference and likelihood of biota productivity. The ecosystem productivity region considers the modern topographic delineation and its macro control on the formation of ecosystem landscape characteristics and the influences of monsoon climate and the differentiation of ecosystems caused by light, temperature, water, and other conditions. The productivity zone firstly considers different ecosystem types and their combination characteristics, and then considers difference of ecosystem productivity for different types (e.g., farmland, forest and grassland). According to the value of comprehensive ecosystem productivity for each productivity zone in China, the comprehensive ecosystem productivity of China is divided into 5 grades. Finally, the regionalization divides the whole country into 12 first level ecosystem productivity regions, and 64 second level ecosystem productivity zones.It can be seen clearly from the regionalization that the grade distribution of ecosystem productivity of China is stepwise, which correlates well with the three steps of China’s topographic profiles. The regionalization also indicates that the level of farmland ecosystem productivity can well evaluate the level of ecosystem productivity for most parts of China (i.e., 46 zones). However, for the rest of China (i.e., 18 zones), there exists sharp difference between the level of farmland ecosystem productivity and ecosystem productivity because of the imbalance of regional development.
  • Spatial Variation of Fluorescence Excitation of Water Soluble Organic Matter in Eastern China
    ZHANG Jia shen, TAO Shu, CAO Jun
    2001, 56(4): 409-416. https://doi.org/10.11821/xb200104004
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    Forty six top soil samples covering 20 soil types were collected from eastern China mainly in the summer of 1998 and early spring of 2000. Water soluble organic matter (WSOM) of the samples were extracted with 2∶1 weight ratio of soil to water. Fluorescence excitation spectroscopy was recorded with Hitachi F 2500 fluorescent photometer and molecular size distribution of WSOM was determined with Sephadex G 25. All WSOM samples were not processed with pH adjusting and concentrating. Correlation analysis was used to study spatial variation of the intensity of fluorescence excitation per unit carbon of WSOM and its relationship with average molecular size. Also, the same analyses were performed on fulvic acids extracted from part of the soil samples. It was found that no significant negative correlation existed between the intensity of fluorescence excitation per unit carbon of WSOM and molecular size of WSOC, but partial correlation became true with pH as the controlling factor, showing pH is important to excitation intensity of WSOM without pH adjustment. No similar relationship was found for FA samples, which was considered to be partly due to the small amount of samples of FA (only 12 samples). Both the intensity of fluorescence excitation per unit carbon of WSOM and FA showed the same trend, increasing from south to north in the study area, which was similar to the trend of pH, average molecular size of both WSOM and FA, but opposite to that of the temperature and precipitation. The pH value of soil may play an important role in regulating spatial variation of fluorescent property of WSOM, which needs further investigation.
  • Land Use Pattern in Transect of the Yangtse River and Its Influential Factors
    LONG Hua lou, LI Xiu bin
    2001, 56(4): 417-425. https://doi.org/10.11821/xb200104005
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    The terrestrial transects of IGBP emphasize on explaining issues concerning global change through gradient methods, and land use is one of the gradient factors. The socio economic development extent, largely influencing decade scale land use change, is mainly taken into account to determine the research sphere of transect of the Yangtse River. Accordingly, considering the boundary of district, it covers an area of 1.12 million km 2 or so, contains 310 counties/cities, under jurisdiction of 11 provinces (autonomous regions, municipalities) of Shanghai, Jiangsu, Anhui, Jiangxi, Hubei, Hunan, Chongqing, Sichuan, Yunnan, Qinghai and Tibet. Supported by geographic information system, the land use pattern after a decade or more rapid socio economic development in transect of the Yangtse River is obtained through analyzing and dealing with the land use data of the mid 1990s. Then, canonical correlation analysis is applied to identify the influential factors of land use pattern in transect of the Yangtse River. Through operations of the statistical package for social sciences (SPSS) and specific analysis of the results, the contribution of each influential factor to land use pattern can be identified quantitatively. At the same time, tests are carried out through the canonical correlation coefficient and redundancy analysis. It is concluded that the land use pattern in transect of the Yangtse River is affected by physical factors and socio economic factors synthetically. Through foregoing analysis, abstracted influential factors involve height above sea level, temperature, terrain, economic density (i.e. GDP value per km 2), and village labors density. The distribution of pasture shows positive correlation with height above sea level and negative correlation with the warmest month average temperature, and it implies that pasture is usually distributed in the region with high sea level and low temperature. The positive correlation between economic density and the distribution of land for urban and rural construction shows that rapid socio economic development has been resulting in continuing sprawl of land for urban and rural development. The two factors of the coldest month average temperature and slope have positive correlation with the distribution of woodland. Furthermore, positive correlation between village labors density and the distribution of farmland implies the more village labors in a region, the more farmland proportion.
  • Structural Analysis and Optimal Use of Land Types in Mountainous Regions ——Taking Qinling Mountains of Shaanxi Province as an Example
    LIU Yan sui
    2001, 56(4): 426-436. https://doi.org/10.11821/xb200104006
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    Taking northern slope of Qinling Mountains in Shaanxi Province as an example, This paper puts forward structural multiclass,functional multivariate and spatial arrangement of land type patterns based on systematic analysis of the spatial, quantitative and qualitative structures of land types, and completes the designs of optimal allocation models and schemes of land use in Qinling Mountains The conclusions are as follows: (1) The differentiation of land types in mountainous areas has its own spatial and temporal speciality In spatial dimension, with the change of altitude, the altitudinal differentiation of land types is formed, which represents different zones in a series; in temporal series, owing to the continuous change of natural environment and the influence of human economic activities, a reversible successive series in land use has been produced The speciality in space and time provides a theoretic foundation for the optimal allocation of land use in mountainous areas (2) Structural patterns obviously represent how different kinds of land types combine and their comparison in quality and quantity, which involves three kinds of structures, namely spatial, qualitative, quantitative structures The analysis of structural patterns can disclose the heterogeneity and orderliness of land types in structure and function, and then bring forward theoretical foundation for the design of allocation models in mountainous land use (3) The physical zonality, vulnerability in environment, multilevel and complexity of landscape determine the necessity and speciality in land use optimal allocation based on mountainous land structural patterns The optimal allocation of mountainous land use ought to obey the theories of landscape ecology and sustainable development, comprehensively analyze its ecological suitability in present land use, suitability of land types and scientific decision making in ecological design of mountainous land use, and advance the ecological model and measures to optimize the structure and layout in mountainous land use (4) The optimal allocation model of land use, in some sense, generalizes and describes systematic structural characteristics and functional attributes of mountainous land use In spatial dimension, it consists of three models in detail, namely macro regional, meso industrial and micro operational models The solution of optimal allocation is the concrete representation of the optimal allocation model in mountainous land use, which, virtually, is the optimization of industrial land use structure and layout, and is suitable and practical in mountainous land use Its implementation, however, ought to be brought into all round and special layouts of regional land use, get the support of the economic and social factors including investment, technology and labor as well as conversion of ethical ideology in land use.
  • The Analysis of Rural Settlement Hollowizing System of the Southeast of Taiyuan Basin
    CHENG Lian sheng, FENG Wen yong, JIANG Li hong
    2001, 56(4): 437-446. https://doi.org/10.11821/xb200104007
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    In this thesis, a definition for hollowization settlement is given on the basis of the principles: the relative quality, the functional transformation, the absolute abandonment and the sharp decrease in population. Based on Radar Model, 5 subbreeding environment types of hollowizing settlement are revealed: Type 1: easiest hollowizing environment which contains 4 impelling factors; Type 2: easier hollowizing environment which contains 3 impelling factors and 1 retraining factor; Type 3: plane and easy hollowizing environment which contains 2 impelling factors and 2 retraining factors; Type 4: more difficult hollowizing environment which contains 1 impelling factor and 3 retraining factors; Type 5: most difficult hollowizing environment which contains 4 retraining factors. Two indices including relatively hollowizing rate and absolute hollowizing rate are applied for expounding the hollowizing state of the settlement in the region. Two location sensibility indices( w J and w x ) constitute 2?2 rank matrix which divides the settlements of the region into four hollowizing ranks: Rank 1: high speed hollowizing settlement, w J>1,w x>1; Rank 2: steadily hollowizing settlement, w J>1,w x<1; Rank 3: latently hollowizing settlement, w J<1,w x>1; Rank 4: slowly hollowizing settlement, w J<1,w x<1. According to the price consumption budget line and the theory of land price, 3 driving powers covering the low building cost, the comparative profit and the consumption budget are discovered. Concerning the basic line, buffering line and end line, one hollowizing settlement space is divided into 3 parts: the core zone, buffering zone and the new expanding zone. Based on the growth declining state of the hollowizing settlement space, 5 patterns of the settlement hollowizing process are posed: (1) the growth process pattern of the core zone; (2) the expanded process pattern of the core zone; (3) the growth process pattern of the buffering zone; (4) the expanded process pattern of the buffering zone; (5) the growth process pattern of the new expanding zone. The checking measures against the settlement hollowizing are discussed lastly.
  • Effects of Land Use on Soil Quality in a Hilly Area ——A Case Study in Zunhua County of Hebei Province
    GUO Xu dong, FU Bo jie, CHEN Li ding, MA Ke ming, LI Jun ran
    2001, 56(4): 447-455. https://doi.org/10.11821/xb200104008
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    How to use rationally the lands in hilly areas is very important to preserve soil quality and develop sustainable land use model. This study was undertaken to evaluate the effects of land use on soil nutrients and soil bulk density in the hilly area of Zunhua County of Hebei Province. Samples were collected from top soil (0～20 cm) of pine forest, grassland, chestnut forest, and slope farmland that had been cultivated for about 6 months and for over 3 years. The results indicated that deforestation and cultivation led to increase in soil bulk density and decrease mostly in soil nutrients. Compared to pine forest, the bulk density value of grassland, 6 months’s cultivated land, chestnuts and 3 years cultivated land increased by 13.3%, 14.2%, 27.5% and 39.7%, respectively. Most soil nutrients except available N and available P showed significant differences among different land use types. Soil nutrient contents except total P in chestnuts and over 3 years cultivated soils decreased significantly in comparison with pine forest. Chestnut forest witnessed a decrease in soil organic matter by 60.7%, total N by 35.6%, total K by 21.3% and available K by 57%; while over 3 years cultivated soils saw a decrease in SOM by 62.9%, total N by 52.6%, total K by 31% and available K by 60%. The soil degradation indices showed that grassland and slope farmland cultivated for about 6 months did not degrade significantly, however, a severe degradation occurred to over 3 years’s cultivated land and chestnut forest. Obviously, cultivation on steeper slopes results in severe soil degradation and diminishes greatly soil quality. It seems that the development of chestnuts by deforestation is also not a sustainable land use model though more income can be obtained. The soils under chestnuts will subject to severe degradation unless appropriate soil and water conservation practices were conducted.
  • Mono-window Algorithm for Retrieving Land Surface Temperature from Landsat TM6 data
    Qin Zhi hao, Zhang Ming hua, Arnon Karnieli, Pedro Berliner
    2001, 56(4): 456-466. https://doi.org/10.11821/xb200104009
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    Landsat TM data has a thermal band (TM6) to monitor the thermal radiance and surface temperature of the earth. For a long time, retrieval of surface temperature from TM6 data is done through the method called atmospheric correction, which requires the estimate of atmospheric thermal radiance and absorption. The computation is complicated and the accuracy is strongly subjected to the estimate, hence has few applications in real world. In this paper, a new method with simple computation and high accuracy is developed on the basis of thermal radiance transfer equation of the ground. The impacts of both atmosphere and the emitted ground on the thermal radiance transfer of the ground are directly involved into the proposed algorithm, which requires 3 essential parameters for the retrieval: emissivity, transmittance and atmospheric average temperature. Validation indicates that the accuracy of the algorithm is high up to <0.4℃ for the estimate of the essential parameters with no errors and <1.1℃ for the estimate moderate errors. Since the method is applicable for the remote sensing data with only one thermal band, it has been termed as mono window algorithm.
  • Variation of Precipitation in Shanghai during the Last one Hundred Years and Precipitation Differences between City and Suburb
    ZHOU Li ying, YANG Kai
    2001, 56(4): 467-476. https://doi.org/10.11821/xb200104010
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    Based on the observed data of precipitation during 1893～1999 in Shanghai and its suburbs during 1961～1999, by means of power spectrum analysis and some statistical methods, including cumulative anomaly percentage, 11 year running average, t tests for paired samples etc, this paper mainly discusses the space time features of precipitation in Shanghai The results obtained are as follows: (1) The variation of precipitation in Shanghai has been obvious in the last one hundred years There are more rainfall in the 1990s comparing with other decades in the 20th century and less in the 1960s The anomaly of annual precipitation varies from -33 4%(1978) to 54 8%(1999) A total of twenty drought and flooding years for the time span of 1893～1999, thus the probability of normal annual precipitation is 81 3% (2) The significant periodic components of inter annual precipitation are 2a, 3 2a and 35 2a The climate in Shanghai from 1893～1999 can be divided into six periods which include three dry ones, dwelling from the end of the 19th century, from 1921～1940 and 1960～1981, and three wet ones dwelling from 1906～1920, 1941～1959 and 1982 to the beginning of the 21st century The amplitude of variation of dry/wet period has increased since 1960 The recent wet period seems to extend (3) The effect of rain island influences the time and space distribution of precipitation in Shanghai It shows that the precipitation differences between the urban and suburban areas (except the newly developed districts of Minhang and Pudong) are significant, with 2 tailed sig value being less than 0 01 Annual precipitation increment in the urban area is one and a half times as much as that of the suburbs Regional precipitation differences in the 1980s and the 1990s have been enlarged by 1%～3% comparing with that in the 1960s and the 1970s (4) The rain island effect in Shanghai mainly exists from June to September which covers two important rain periods— the plum rain and the typhoon rain During these months precipitation in the northern part of Shanghai is more than the southern On the other hand, there is no rain island effect from the end of autumn to next May and the southern Shanghai has more precipitation than the northern Precipitation from June to September is signified by an obvious long term trend, while precipitation from October to next May displays fluctuations.
  • Temporal-Spatial Distribution Characteristics and Causes of Dust-day in China
    QUAN Lin sheng, SHI Shao ying, ZHU Ya fen, QIAN Wei hong
    2001, 56(4): 477-485. https://doi.org/10.11821/xb200104011
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    In this paper, the daily 850 hPa geopotential high data of NCEP/NCAR reanalysis for 1948～1999 are used to find the vortex fluctuations, which represent daily cyclone activity in northern China. Three data sets, the grid cyclone frequency for 1948～1999, the 160 station temperature and precipitation for 1950～1998 are used to calculate the correlation with the 338 station dust day frequency for 1954～1998 in China’s mainland. The result shows that the frequency of dust day is strongly corresponded with the low air temperature in winter and cyclone activity in spring. Based on this relationship, an index describing dust day frequency has been formulated. This dust index can well calibrate against the variability of dust day in northern China, except for Xinjiang region in Northwest China.
  • Double-Thresholds in the Scour-Fill Process of Wide-Range Water-Sediment Two-Phase Flows and its Implications in Geomorphology
    XU Jiong xin
    2001, 56(4): 486-493. https://doi.org/10.11821/xb200104012
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    Through an analysis of the data from some rivers on the Loess Plateau of China, the phenomenon of double thresholds in scour fill process of wide range water sediment two phase flows has been found. The threshold located in non hyperconcentrated flows may be called the lower threshold, and that in hyperconcentrated flows the upper threshold. This double threshold phenomenon plays an important role in sediment transportation of heavily sediment laden rivers. With the increase in sediment concentration, the channel sediment delivery ratio shows an increase first, followed by a decline, intersecting twice with the straight line representing the sediment delivery ratio of 1.0. The two intersection points correspond the lower and upper thresholds, respectively. A new explanation for alluvial channel pattern formation can be reached considering the double thresholds in scour fill process of wide range water sediment two phase flows. Based on the data from nearly 100 alluvial rivers in China, the mean annual sediment transport rate has been plotted against water discharge, with different channel patterns, i.e., meandering at low concentrations, braided and meandering at hyperconcentrations represented by different symbols. The three patterns can be well differentiated by the straight lines represented by suspended sediment concentrations of C=60 kg/m 3 and C=3.3 kg/m 3. The two characteristic concentrations can be regarded as a reflection of the double thresholds in scour fill process of wide range water sediment two phase flows in rivers.