In this paper, species composition, biomass change pattern and differences of 2 types of alpine vegetations in the northeastern part of Qinghai were analyzed. Monitoring results showed that there were significant differences in soil humidity moisture and evaporation between Kobresia humilis meadow and Potentilla fruticosa shrub which grew in the same regions with similar altitudes and precipitation but different topography. The species constitute 2 types of alpine vegetations which are different due to limitations of environmental factors, especially soil temperature and moisture. With respect to the general biogeography of the region, the Potentilla fruticosa shrubs, dominated by Potentilla fruticosa and accompanied with Kobresia capillifolia, Kobresia pygmaes, Festuca ovina and some forbs, are found on the northern slopes. The Kobresia humilis meadows, typical alpine meadow dominated by Kobresia humilis and accompanied with Elymus mutans, are widely distributed along the valley floor. The above-ground biomass of Kobresia humilis meadow is greater than that of Potentilla fruticosa shrub. As for underground biomass (0-40 cm), both types of vegetations maintained relatively great values during the period from May to September, but the occurrence time of its peak value and the lowest value differs from each other for the 2 types of vegetations. The annual net underground production of Potentilla fruticosa shrub is greater than that of Kobresia humilis meadow, whereas, the turnover value of underground production of Kobresia humilis meadow is greater than that of Potentilla fruticosa shrub.

Based on the "shortest path matrix", the selected characteristic indices-distance, time and speed, this paper analyses the current spatial structure of accessibility in the cities which the national trunk highway system connects, and impacts the speed index made. The cities connected by the national trunk highway system turn out the obvious "core-periphery" model with speed index. The top 50 most accessible cities are concentrated in the middle of eastern China, and the bottom 50 ones are located at the periphery such as northwestern, southwestern and northeastern China. The spatial structure of accessibility measured by time index shows a concentric layer structure with attribute falling gradually from interior to periphery. Moreover, the spatial structure of accessibility in cities connected by the national trunk highway system has obvious boundary effect, which shows wave transformation under different speed conditions. The evidence shows that the change in speed acceleration of the national trunk highway system with an urban accessibility of 60-80 km/h is significantly greater than that of 80-100 km/h. For a given city, averaged 33 cities can be reached within eight hours--a normal working day. Most of the cities with the maximum urban access in eighty hours are concentrated in eastern China, averaged 70 cities. The cities with the minimum urban access in eighty hours are located in the northwestern, southwestern, northeastern and southeastern parts of China. Besides further construction, accelerating the speed of the future national trunk highway system will bring about more impacts on the spatial structure of the cities in China.

The MODIS product of the land surface vapor flux (MOD16) is not yet released by NASA because some parameters in the algorithm are very unstable in the time and space scales, which are difficult to be or cannot be derived from the remote sensing data. In this study, we validated the original algorithm of MOD16 with the ground measured data from April to May in 2002 (Yucheng Ecological Experimental Station in Shandong, CAS). The result showed that the estimated vapor flux was about 20% more than the observed values. We revised the original model by adjusting the crop physiological temperature parameters and coefficients for calculating the aerodynamic resistance, and the fractional vegetation cover according to the characteristics of winter wheat in Yucheng Station. The slope of the regression line plotted with the result simulated by the revised algorithm and the field measured data was 0.9706, and the correlation coefficient (R₂

By transplanting original plants/soil system into lysimeters and treating those lysimeters with five precipitation treatments: 80%, 90%, 100%, 110% and 120% of the average annual precipitation, plant productivity and soil moisture were observed. Field experiment in Yuansi county, Hebei, showed that precipitation change was a very sensitive factor influencing both the productivity and soil moisture. Precipitation increase resulted in the increase of productivity. When precipitation increased by 10%, productivity increased by about 15%. The experiment also showed that higher precipitation generally resulted in higher soil moisture, which should be the reason for productivity increase in high precipitation treatments, though good plant growth, in some treatments, might also feed back on the soil moisture change. In order to see the possible effect of both temperature and precipitation changes on soil moisture, without changing plant growth pattern, WAVES model is calibrated, validated and used for the simulation of response of soil moisture to climatic change. The simulation shows that temperature associated with precipitation decrease or no precipitation change will definitely result in the decrease of soil moisture, indicating a great possibility of plant productivity decrease. Though precipitation increase would benefit the soil moisture, however, it is showed that 10% precipitation increase will not bring any benefit to soil moisture if temperature rises by 4 ^oC. Precipitation rise by 10% will possibly create only a slightly favorable soil moisture condition if temperature rises by 2 ^oC. It is thus suggested that the positive effect of 10% precipitation increase on soil moisture will possibly be offset by roughly a temperature rise of 3 ^oC . As soil moisture is the key factor influencing plant productivity, plant productivity will possibly follow the same trend. However, since the effect of CO₂ concentration rise on plant transpiration and plant growth is not considered in the model simulation, there are still quite a lot of uncertainties remaining. The results need to be testified by future studies.

Photosynthetically active radiation (PAR) is a key variable required by almost all terrestrial ecosystem models. Unfortunately, the current incident PAR products estimated from remotely sensed data at spatial and temporal resolutions are not sufficient for carbon cycle modeling. In this paper, a method was proposed to retrieve land surface PAR from MODIS data in non-cloudy sky. Firstly, the maximum PAR in top of atmosphere was calculated in any place and at any time. Then the atmospheric parameters, vapor and aerosol, were estimated from MODIS data. Finally, the land surface PAR was computed by radiative transfer model using atmospheric parameters and sun geometrical information. The method was used to retrieve PAR in Shandong and the result was tested by the ground data in Yuncheng station of CERN with the error less than 10%.

The resource and environment in Tibet is unparalleled. It is important to make full use of new high-tech for socio-economic sustainable development and ecosystem protection. Based on the richness of information from the explorations, the construction of resource and environment information system in Tibet is absolutely necessary. In this article, after the analysis of system demand, the system architecture, database content and system functions are introduced and a wonderful future of this system is described.

There is an increasing demand for the exploration of geo-information by visualization. The paper mainly deals with a multimedia electronic mapping system, composed of preprocessing sub-system, map-making subsystem and map-view sub-system. The spatial cognition on geographic objects and their spatial semantic relationship is emphasized. A psychological cognition model is introduced for the associative and humanized representation of concept and knowledge, so as to facilitate developing application-oriented multimedia system.

The Tibetan Plateau is the least human-disturbed region in the world. Its outstanding topographic features and ecological characteristics give it a fame of "Natural Lab" for global change research. An improved TEM model based on MODIS satellite data and field observations data during 2000-2002 were used to estimate annual net primary productivity (NPP) in the Tibetan Plateau. A validation by using the observed NPP at different sites shows that the estimated NPP is well agreed with the measured NPP. The simulated results show that the estimated annual primary productivity of the entire Tibetan Plateau is 302.44×1012 gC yr^-1, among which forest NPP takes up 39.7% of the total, though forests comprise only 9.74% of the Tibetan Plateau region; NPP accumulation for summer is 246.7×1012 gC yr^-1, which is 80% of the year total.

This paper describes a method for the estimation of the net primary productivity (NPP) by integrating remotely sensed and GIS data with a process-based ecosystem model. Hokkaido Island of Japan was selected as a case to validate our method. In order to improve the estimation accuracy, we improved the BEPS model (Boreal Ecosystem Productivity Simulator) for NPP estimation by incorporating new land cover classification logic, a robust Normalized Difference Vegetation Index-Leaf Area Index (NDVI-LAI) algorithm and employing GIS data with high quality as the input of the model. As the results of the model calculation, the mean and total NPP for the study area in 1998 was 644 g C/m²/yr and 0.078 Gt C/yr, respectively. In addition, the effect of the quality of the model input requirements on accurate NPP estimation using a process-based model was also assessed. The results show that the higher quality input data obtained from GIS datasets for a process-based model improved the NPP estimation accuracy for Hokkaido Island by about 16.6%-39.7%.

By using Terra/MODIS satellite data in 2002, the dynamic variation of surface water area and water storage in Dongting Lake was studied. We, at first, divided the whole Dongting Lake into three parts (WDL: West Dongting Lake, SDL: South Dongting Lake, EDL: East Dongting Lake from west side) according to geographical characteristics. Secondly, surface water area was detected based on the spectral deference between water and terrestrial area using satellite (Terra/MODIS) NDVI (Normalized Difference Vegetation Index) data. Thirdly, the surface water area was overlaid on the lake bottom DEM with a grid size of 50 m by 50 m, and the water level could be calculated. Finally, the water storage was obtained by times water depth (difference between water surface elevation and lake-bottom elevation.) with the grid area. The total water storage at Dongting Lake was calculated by accumulating all water column values in the whole lake. By comparing the estimated water level and storage with the measurements in the three parts of the Dongting Lake, we found that there are high correspondences between the two, which implies that our method is an effective approach to estimate water level and water storage of a large lake.

In 2009, a total of nearly 900 million international tourist arrivals were counted worldwide. A global activity of this scale can be assumed to have a substantial impact on the environment. In this contribution, five major aspects such as the change of LUCC and the use of energy and its associated impacts had been recognized. Recently, the impact of tourism on environment and climate attracts the attention of international organizations and societies in pace with rapid development of tourism industry. Energy consumption and CO₂ emissions in tourism sector has become a hot topic of international tourism research in recent five years. The use of energy for tourism can be divided according to transport-related purposes (travel to, from and at the destination) and destination-related purposes excluding transports (accommodation, food, tourist activities, etc.). In addition, transports, accommodation and food are related to many other industries dependent on energy. Thus, the estimations of energy consumption and CO₂ emissions in tourism sector have become a worldwide concern. Tourism in China grows rapidly, and the number of domestic tourists was 1902 million in 2009. Energy use and its impact on the environment increase synchronously with China's tourism. It is necessary to examine the relationship between energy use and CO₂ emissions. In this article, a preliminary attempt was applied to estimate the energy consumption and CO₂ emissions from China's tourism sector in 2008. Bottom-up approach, literature research and mathematical statistics technology were also adopted. According to the calculations, Chinese tourism-related may have consumed approximately 428.30 PJ of energy in 2008, or ahout 0.51% of the total energy consumptions in China. It is estimated that CO₂ emissions from tourism sector amounted to 51.34 Mt, accounting for 0.86% of the Chinese total. The results show that tourism is the industry of low-carbon and the leading industry coping with global climate change, energy-saving and CO₂ emission reduction. Based on this, the authors hold that tourism should become an important field in low-carbon economy.

The original purpose of the TOPEX/ Poseidon was to measure sea surface height. Making use of the concept, "assuming datum plane", TOPEX/Poseidon derived water level changes data were converted to water level data. Furthermore, the rating curve between satellite-derived "water level" and in situ river discharge was established. Using this approach, the actual river discharge can be determined from TOPEX/Poseidon data without the need of the actual water level. Based on the two years (1998, 1999) TOPEX/Poseidon data and ground observed river discharge data around Datong station which is located in the lower reaches of the Yangtze River, the approach was validated. The results show that TOPEX/Poseidon data can be used to determine river discharge in the lower reaches of the Yangtze River.

In order to acquire high resolution, data fusion technique can be used to combine multiple data from different sensors. This study practices two methods of data fusion: IHS transformation method and wavelet-based method. The result showed that IHS transformation method was a relatively simple one to be used, but it can not remain all information except for three bands of RGB. However, the wavelet-based method is relatively complicated and it can get high resolution images in all bands. As an approach to scale down the resolution of images, a so-called pixel level data scaring model was used in this study. Comparisons were made from data acquired by four multi-spectral sensors (Landsat/ETM+, Terra/ASTER, Terra/MODIS, and NOAA/AVHRR) over Kushiro Marsh in Hokkaido, Japan, on September 26, 2001. To reveal the effect of the sensors' spatial resolution, simulated data are generated from the higher spatial resolution (small size pixel) data to match the lower spatial resolution (larger size pixel) data. The result shows that the Terra/ASTER images can be effectively down-scaled to the resolution of Landsat/ETM+. However, it is rarely effective to scale down both Landsat/ETM+ and Terra/ASTER images to the resolution of MODIS and AVHRR.

This paper expounded the author's study on the geo-analysis of various information sources including Geo-Science characteristics and time property of remote sensing image, such as Agro-phonological date (Heading data of rice, heading spring maize and tillering & jointing date of wheat) in different areas. RS image mapping is based on knowledge and application of fusion information technical system in RS image thematic mapping.

In order to better understand the biogeochemical process of the Changjiang (Yangtze) River and pollutant load flowed into the East China Sea from the river and provide scientific basis for eco-environmental and water resources protection, field surveys along the Changjiang River from Chongqing to Shanghai (about 2300 km long) were carried out in autumns of 1998 and 1999 through the international cooperative study between the National Institute for Environmental Studies (NIES), Japan and the Changjiang Water Resources Commission, China. In this paper, the preliminary results of water quality conducted in the joint survey were presented. From the concentration variations of SS, DOC, T-P, NH_4-N, NO_3-N and DT-N along the main course of the Changjiang River during both surveys of 1998 and 1999, it is evident that the concentrations of SS and nutrients in the autumn of 1999 were higher than that in the summer of 1998, because the influence of non-point pollutant source and the discharge and water level during the survey period in 1999 was much higher than that in 1998. On the other hand, the general tendency of the nutrient distribution increased from upstream to downstream along the main course of the Changjiang; the concentrations of nutrients were evidently higher in the downstream of big cities than that in the upstream of these big cities. Water quality was improved after passing through the Gezhouba Dam. It was also found that the BOD and NH_4-N concentrations increased sharply after passing Dongting and Poyang lakes.

To evaluate the performance of a computer model simulating runoff in the upper reaches of the Changjiang (Yangtze) River Basin over a relatively short time interval, including examining the applicability of the input precipitation data generated from global circulation models and satellite data, we used a spatially distributed model, HSPF with the ISLSCP precipitation data for 1987 and 1988 as input data. The Nash-Sutcliffe coefficient (R₂) for 5-day average stream flow was 0.94 in the calibration period and 0.95 in the verification period for the whole upper region. Moreover, the model simulated the 5-day average stream flow well in each main tributary, as shown by R₂ values of 0.46 to 0.96, except that it underestimated the peak flow rates during the flood season over two years by up to 71% in the Tuojiang River and 61% in the Jialingjiang River. The ISLSCP precipitation tended to be more frequent and less intense than the measured precipitation. This was probably the main reason why the HSPF did not perform well in all regions at all times.

Though the annual total sediment load at Yichang hydro-station increased from the 1950s to the 1980s, it tended to decrease gradually in the 1990s. The reason of increase is due to violent deforestation and rapid landuse change, while that of decrease may be due to countermeasures taken to control sediment yields and lots of dams built on the upstream basins. The Jialingjiang River watershed is one of the main sources of sediments in the Changjiang river watershed, and the annual total load in the 1990s from the Jialingjiang River basin discharged into the Changjiang River reduced to about 36% of that before 1988. To clarify the reason of decrease of annual sediment-inflow rate in this basin is of great significance to sediment control related forest planning, reservoir sedimentation prevention at the Three Gorges Dam and habitat and ecosystems preservation in the Changjiang River, etc. In this study we developed a surface erosion type of sediment yield model for watershed slope, applied it to Jialingjiang River watershed in 1987, and investigated its applicability.

After an introduction to the background, general characteristic, objective, scheme, part division and map types about the atlas, a new computer aided design method for maps is given and presented as the following parts: map designing, establishment of graphic database for geographical base map, computer map compiling and plate making technology and flow designing.

For implementing water resources management in the Yellow River Basin, water resources assessment is very necessary and important. The accuracy of water resources assessment relies on predictability of the hydrological cycle. Different land uses, topographical features, geological and soil conditions, and artificial water uses (mainly agricultural irrigation) determine the complexity of hydrological characteristics in this basin. With the limited observation of the river discharge, it is difficult to develop a lumped model for simulating hydrology in different sub-basins based on parameter calibration. The physically-based hydrological model can be helpful in this case. The present research attempts to incorporate all available spatial information into the hydrological modeling by a distributed approach. A physical model is developed using the physical governing equations for description of the hydrological processes. It carries out a 10-year (1980-1989) simulation of the natural hydrological cycle. Based on the hydrological simulation, the paper discusses the spatial-temporal hydrological characteristics and the status of water resources in the Yellow River Basin.

Tourism has made great progress in China since the implementation of reform and opening-up policy, and the quantity of foreign and domestic tourists has a great increase not only in every province but also in cities. Based on the theory of primate city distribution and rank-size distribution which have been frequently used in urban geography since the 1920s, this paper uses the date of major cities and provinces to explain tourism size distribution on the scale of province and single city in China. Considering the possible error in recording the number of the domestic tourists, this paper selects the number of foreign tourists as the criterion of tourism size. On provincial scale, tourism size distribution follows primate city distribution, Beijing and Guangdong province are the primate province (city) in turn since 1990, the primate quotiety is between 1 to 1.6. What is more, according to the balance of the size and rank change, the tourism size growth mode of the province in China can be classified as equalization mode, accelerate growth mode, decelerate growth mode whereas through regression, tourism size turns out to follow the rank-size distribution on single city scale, the tourism size and its rank accords with the Pareto distribution well. Besides, this paper also discusses the impacts of the facts, such as economic condition, city function, tourism resource and boundary port on tourism size distribution, aiming at offering a new method for research of the tourism size and assisting the formulation of tourism policies at national and regional levels.

In this paper we tried to analyze agricultural land use changes in Beijing City, and make clear their spatio-temporal structure. The sectoral structure of cultivated land is closely related to the physical land conditions, so that distribution of agricultural land use is basically determined by land conditions, which is one of the basic driving forces. As regards food crops cultivation, its sectoral structure is closely related to the driving forces as complex of land conditions, industrialization, policies, infrastructure and innovation. Although the sectoral structure of vegetables cultivation is closely related to the available land conditions, it is more important for them to develop alternative economic activities with the growth of urbanization and socialist market economy. On the other hand, the sectoral structure of fruits production is most closely related to the enlargement of profitability with the growth of urbanization and socialist market economy rather than the available land condition and alterative economic activities. Following our discussion, it seems to be concluded that sectoral differences of agricultural land use in Beijing City have been generally presented since the 1980s. This sectoral structure has been closely related to the complex of driving forces such as land conditions, agricultural policies, the alternative economic activities and urbanization. In addition, we calculated through mesh data of village and township statistics in Beijing City. Food crops productivity will be raised greatly due to constant agricultural technology innovation, and food crops land ratio will rise to 75% by 2020. Vegetables productivity will make marked progress in the inner urban fringe, and it will decrease greatly in the outer urban fringe of Beijing City. Vegetables land ratio will also reach 15% by 2020. Types of fruits productivity and culture of fruits over Beijing City by 2020 will not change much than now.

Ranging from 83^o41' to 95^o11'E and from 30^o27' to 35^o39'N, northern Tibet in the highest of Tibet is known as the ridge of the roof of world with a mean elevation of 4500 m. Northern Tibet is the headstream of the Yangtze River, Nujiang River and Lancang River. It is both the "sensitive area" of climate system and the "water tower" of China. The environmental condition of this area has significant effect on the main rivers, climate and eco-environment of Tibet and the whole country, even on the globe for its rigorous natural condition and fragile ecosystem. This study selected vegetation cover as the main evaluation index, calculated the grassland degradation index (GDI) and established the remote sense monitoring and evaluation system for grassland degradation in northern Tibet, according to the national standard (GB19377-2003), based on the remote sensing data such as NDVI data derived from NOAA/AVHRR with a spatial resolution of 8 km of 1981-2000 and from SPOT/VGT with a spatial resolution of 1 km of 2001 and from MODIS with a spatial resolution of 0.25 km of 2002-2004 respectively in this area, in combination with the actual condition of grassland degradation. The grassland degradation processes and their response to climate change during 1981-2004 were discussed and analyzed systematically in the study. The result indicated that grassland degradation in northern Tibet is very severe, and mean value of the GDI in recent 20 years is 2.54 which belongs to the severe degradation grade. From 1981 to 2004, the grassland degradation fluctuated evidently with great interannual variations in proportion of degradation degree and GDI but the total tendency turned to severe during this period with the grassland degradation grade changed from light to severe in northern Tibet. The extremely seriously degraded and seriously degraded respectively occupied 1.7% and 8.0% of the study area, the moderately and lightly degraded grassland accounted for 13.2% and 27.9% respectively and un-degraded grassland occupied 49.2% of the total grassland area in 2004. The grassland degradation was severe especially in the conjunctive area of Naqu, Biru and Jiali counties, the headstream of the Yangtze River that is Galadandong snow mountain, the areas along the Qinghai-Tibet railway and highway, and areas around the Tanggula and Nyainqentanglha snow mountains and glaciers. So the snow mountains and glaciers as well as their adjacent areas in northern Tibet which were sensitive to climate change and the areas along the vital communication line with frequent human activities experienced relatively severe grassland degradation.

Based on the improvement of current international major customer satisfaction index models, and taking the characteristics of tourist attraction into consideration, this paper puts forward a creative model of Tourism Attraction Customer Satisfaction Index (TACSI). It is a structural equation model with casual relationships, which is made up of 7 latent variables and 23 observed variables. There are 11 kinds of positive and negative correlativities among the 7 latent variables. Trunk Hill Park in Guilin is taken as an example in empirical study. By means of LISREL, the test result on TACSI model indicates that the measurement model has high goal dependability since the observed variables have a significant effect on customer satisfaction; the path coefficients between the latent variables are basically consistent with the assumption; and the whole TACSI model has a good goodness of fit. In addition, the authors compare the fitness result of TACSI model with ACSI model, which shows that TACSI model is more feasible because it can explain the variables better than ACSI model.

On maintaining ecological balance and promoting economical development, it is necessary to strengthen the spatial relation among the landscape patterns whose functions are similar. The growing awareness of the adverse effects of habitat fragmentation on natural systems has resulted in a rapidly increasing number of actions to reduce current fragmentation of natural systems as well as a growing demand for tools to predict and evaluate the effect of changes in the landscape on connectivity in the natural world. For promoting and positioning functions of each landscape unit in the whole Taiwan island, systematically studying characteristics of landscape patterns in the research areas, and identifying energy routes of landscape function flows, this study chooses the basic regionalism units as the research areas such as Wuxi watershed to analyze connectivity traits among network nodes with single function as well as spatial interactions of different functional networks based on landscape function network establishment. Then from the aspect of consolidating network configuration to strengthen landscape functions, this study puts forward some strategies to optimize landscape patterns. Through linkage analysis of network nodes, it is found that urban function network structure is better than ecological function network in Wuxi watershed, and most urban function sub-nodes are located around the urban function centers, which can allow landscape functions export and transmit. The connectivity of ecological function nodes is similar, but the first and second level nodes such as Hongxiang and Gaomei wetlands are isolated and less connected, so this study proposes to consolidate function transmitting routes and highlight significance of main transferring nodes like Erzhaishan and Beikengzi aiming at optimizing ecological landscape in Wuxi watershed.

In this study, plot and watershed scale experiments were conducted to study the effect of some extraordinary rainfalls on the export of nutrients from agricultural land. The results of three-year plot experiments show that more than 50% of annual nitrogen and phosphorus losses via surface runoff happened between June and August, when the monsoon and typhoon rains are heavy and frequent. During the three largest storms, 35.7%-52.4% of the annual N and 46.8%-66.4% of the annual P were exported by surface runoff from different land use types. Nutrient concentrations increased with hydrological process during storm flow, decreased with the prolongation of storms yet remained at higher concentrations compared with base flow time. About 30% of N and more than 40% of the annual P loads were exported from the watershed by the four largest storms. Reducing agricultural practices such as tillage and fertilization during frequent heavy rainfall period are effective ways for mitigating agricultural nonpoint source pollution.

To obtain an overview of land use effects on the accumulation of Pb in the soil, 600 samples were collected from Beijing. The results showed that the geometric mean of all soil samples was 26.6 mg/kg, significantly higher than the background concentration of Beijing soil (24.6 mg/kg). Based on the assessment compared with background concentration, increasing of Pb was found to be the highest in greenbelt and orchard and to a somewhat lesser extent in vegetable field and paddy field, whereas anthropogenic input seemed to be less important in natural soil. And the concentrations of Pb in greenbelt and orchard were significantly higher than those in other land use types. Using baseline as the criterion, the orchard showed the highest ratio beyond the limit for 21.4%. Corresponding values of greenbelt, vegetable field, paddy field, and cornfield were 18.2%, 11.1%, 8.3% and 5.2%, respectively and 7.2% for the total samples. The samples over the limit were mainly distributed in districts of Changping, Chaoyang, Daxing, Fengtai, Haidian and Shijingshan. The six districts were attributed with high ratios beyond the baseline limit for soil samples. Therefore, the concentrations of Pb in the soils declined gradually with the increment of the distance of the soils from the city zone. Through present investigation, it was found that the impacts of human activities of atmospheric precipitation, landfill of waste and fertilizer application are probably the important reasons for Pb concentrations under different land-use types.

Having analyzed the tree ring width and maximum latewood density of Pinus densata from west Sichuan, we obtained the different climate information from tree-ring width and maximum latewood density chronology. The growth of tree ring width was responded principally to the precipitation in May, which might be influenced by the activity of southwest monsoon, whereas the maximum latewood density reflected the summer temperature (June-September). According to the correlation relationship, a transfer function had been used to reconstruct summer temperature for the study area. The explained variance of reconstruction is 51% (F = 52.099, p < 0.0001). In the reconstruction series: before the 1930s, the climate was relatively cold, and relatively warm from 1930 to 1960, and this trend was in accord with the cold-warm period of the last 100 years, west Sichuan. Compared with Chengdu, the warming break point in west Sichuan is 3 years ahead which shows Tibetan Plateau was more sensitive to temperature change. There was an evident summer warming signal after 1983. Although the last-100 running average of summer-temperature in the 1990s was the maximum, the running average of the early 1990s is below the average line and it was cold-summer; summer-drought presented in the late 1990s.

Based on 740 stations daily precipitation datasets in China, the precipitation- concentration degree (PCD) and precipitation-concentration period (PCP) of different intensity durative precipitation events were calculated to analyze their statistical characteristics, mainly including spatial and temporal distributions, variations and climatic trends of the two parameters of the durative heavy precipitation events in China. It is proved that these two parameters of heavy rainfall can display the temporal inhomogeneity in the precipitation field. And it is also found that there is a good positive relationship between the precipitation-concentration degree and annual rainfall amount in eastern China and central China. This method can be applied in flood assessment and climate changing fields.