At present, there isn't a flexible and actually running distributed hydrological model in the Hai river basin. Based on SWAT (Soil and Water Assessment Tool), a whole basin distributed hydrological model for Hai River basin is presented. In this model, according to the Hai river basin characteristics, the river networks in the plain region is reasonably modified, the 17 river mouths are generalized, the 28 big reservoirs are considered. Because of the difference between China and USA, the soil type database and land use types are transformed and reclassified. By using the hydro meteorological data from 1995 to 2002, we carry on the optimization and sensitivity analysis of the model parameters based on the parameters analysis system building by ourselves. The simulation results are reasonable and can provide the important hydrology supporting foundation for the water resources management and the eco- environment's restoration in the Hai river basin.
To protect and rehabilitate health of riverine ecosystem in Chaobaihe River, this paper investigated the ecological implication of the streamflow regime and proposed the concept of ecological flow. The spectrum of the ecological flow includes extreme low flow, low flow, high pulse, high flow and extreme high flow in consistent with those proposed by IHA (Indicators of Hydrologic Alteration). For the case study in the headwaters of Chaobaihe River using daily streamflow data from 1956 to 2003 of Dage Hydrological Station, because of the significant changes of hydrologic cycle, the period from 1956 to 1974 was named reference period, while 1975 to 2003 was named as influenced period. The results showed that the ecological flow spectrum of the influenced period was quite different from that of reference period. The average value of extreme low flow, low flow, high pulse, high flow and extreme high flow are respectively 1.09, 2.43, 6.5, 14.95 and 25 m3/s in reference stage, while the influenced period extreme low flow, low flow and high flow drop respectively by 31%, 4% and 9%, and the extreme high flow disappears but the high pulse was increased by 5%. From the point of view of ecological flow, if the ecological situation in reference period is acceptable for ecological restoration, it is important to increase the quantity of extreme low flow in the headwaters of Chaobaihe River.
Precipitation estimation with high quality and highresolution in time and space is significant for land model simulation, land data assimilation, and the weather, climate and environment research. To estimate precipitation distribution from rain gauge, the traditional methods interpolate the precipitation in space and time without considering the function of the cloud and discontinuity of precipitation incident in time and space. The paper develops a highresolution precipitation estimation scheme by using geostationary satellite data, which estimates six- hour resolution precipitation by using multi- channel satellite data and gauge data, and then interpolates the six- hour resolution precipitation into one- hour resolution precipitation by using cloud precipitation probability as weight. The newly developed method is applied to FY2C satellite data and its 6- hour resolution precipitation data to get one- hour resolution precipitation, and is validated again precipitation observation, which shows that the scheme is reasonable.
Basin level water analysis is the base for scientific water assessment and rational allocation. Traditional basin level water balance analysis mainly adopted simple lumped models based on limited station data. It is hard to meet complicated basin water resource management when consider spatial changes of water cycle. This paper probed into one water balance analysis way with relationship of upstream and downstream considered based on distributed hydrologic simulation technique and take Haihe River Basin for example. Haihe River Basin is located in North China, which spatio- temporal variability of precipitation and evaporation is relatively great. So we built distributed hydrological model using SWAT, base on hydrological process the water balance of the Haihe River basin and the third - level water resource regions is analyzed. According to analysis results, the article also discussed the necessity and countermeasures for maintaining healthy water balance and reducing basin evaportransprition to carry on real water saving in agriculture.
In this paper, we develop a crop distribution data (CLCV- 3C) base on the Chinese Land Cover data (CLCV) and the global crop distribution data developed by SAGE at the University of Wisconsin-Madison, and investigate the effects of crop distribution on land surface simulations over the intake area of the South- to- North Water Transfer Project using the NCAR/ CLM model with the two land cover data. The numerical results show that the crops affect the energy and water balance over the intake area of the South - to- North Water Transfer Project differently; the simulated net radiation, sensible heat, runoff increase, and evapotranspiration decrease in the wheat area, while the simulated net radiation, sensible heat, evapotranspiration increase and runoff decrease in the maize and rice area; the effect of crop distribution on energy balance is greater then that on water balance.
With the effects of climate change and large - scale human activities, interactions between groundwater and surface water become more and more complex and acute. So studying groundwater and surface water as a whole system is urgent now. There are many integrated surface water and groundwater models, and they are divided into different kinds according to different standard. This paper summarized the existing 16 major integrated surface water and groundwater models at home and abroad，and classified them into close coupling and loose coupling. SWATMOD, MIKE - SHE and MODBRANCH model are described in detail on their functions, structures, coupling methods and deficiencies. At last, key problems to be addressed such as conversion of temporal or spatial scale, soil moisture movement in heterogeneous soil, parameter uncertainty, interactions between stream and ground water are pointed out, and the paper concluded that a complicated system model combining all the components in water cycle is the a trend of integrated models’development in present.
Soil quality indicates the effects of natural factors and human activities on land resource. It is important for the imporvment of land quality and sustainable land use to understand deeply the relationships between the spatiotemporal variability of soil quality and environmental factors. The spatiotemporal variation in soil quality means the soil properties show the significant differentiation and diversity at different scales of time and space. Actually, the spatiotemporal variation in soil properties is related to the joint - influences of several environmental factors at multiple - scales including vegetation, land use, meteorological factors (e.g. rainfall), topography and soil. However, the key scale and dominant factors are different for the different time, space and scale. In this paper, the concept and characteristics of spatiotemporal variability of soil quality are first intruduced, then the studies on the spatiotemporal variation in soil quality and its relation to the environmental factors are reviewed. The studies on the Loess Plateau in China are stressed. At the same time, the development trends of soil quality variability are discussed, aiming to provide insights into further soil quality study.
A growing body of literature sheds new light on the importance of the temperature sensitivity (Q10) of soil respiration for understanding terrestrial carbon cycling. It has been well known that small changes in Q10 value will have great influence on soil CO2 efflux, due to its nonlinear response to temperature. Because most of large- scale carbon cycle models are based on the temperature sensitivity, the accurate determination of Q10 value is essential in estimating carbon efflux in terrestrial ecosystems and predicting future climate change. Unfortunately, this value remains uncertain yet. A fixed Q10 of 2.0 has been widely used in modeling leaf - to ecosystem- scale respiration responses to temperature, until several recent studies suggest that Q10 value is not constant during a year, but tends to decrease with increasing temperature and decreasing soil moisture. A fixed Q10 used in empirical or processes- based models, therefore, can result in a greatly over - or under - estimated soil respiration, due to the variability of Q10 value. More insight information in the relationship between Q10 and controlling factors is vital for accurately estimating soil respiration and for developing management strategies to improve soil fertility and to increase C sequestration in soil. In this paper, we reviewed recent advances and hotspots in Q10 research, especially focused on the responses of resistant and labile carbon to temperature. We further reviewed why Q10 value is so variable and explained this phenomenon based on the Michaelis -Menten kinetics. In addition, we reviewed how soil temperature and moisture influence substrate availability and enzymes activity and hence influence temperature sensitivity of soil respiration.
The wetland ecosystem is very complex, which has many characteristics and functions, such as integration, ecology, service, self- maintenance and autoregulation. Based on the ecological complexity theory, the paper analyses the wetland characteristics of Hutuo river from Gangnan reservoir to Huangbizhuang reservoir, and constructs the evaluation system and the standards of the health ranks to diagnose and evaluate the wetland ecosystem health from four aspects: structure, state, function and coordination with the fuzzy comprehensive evaluation model. The result shows that the wetland is in sub- health.
Wuhan “1 +8”metropolitan region plays an extremely significant role in central China's construction as well as in the process of national economic development. From the perspective of spatial pattern, this paper adopts the latest administrative division data, fundamental geographic information database and statistic data to conduct quantitative analysis on both transportation accessibility and regional superiority of the present cities within Wuhan metropolitan region. The result shows an obvious regional advantage for the cities compared with other cities in the province. More specifically, Xiaogan occupies the highest indicators in location among all the 8 cities inside the region while Qianjiang, Xiantao and Tianmen comparatively rank behind. Each city is accessible within two hours from other cities in the region. Wuhan and Xiaogan have the highest increasing speed for traveling time distance, while Tianmen, Huangshi and Xianning behave weak and heed to improve their infrastructure construction.
By the research of the community lodgeable status，we can estimate the city lodgeable and offer the advice and guidance for the community programming of city. This article makes an investigation on Dalian's community by questionnaires, We made a full consideration to the representation and multi - level characteristics of the appraisal factors, and selected 6 second- level indexes and 24 monomial indexes to establish an index system; make use of the basis analysis, we can receive the preference chart of community lodgeable; and make a preliminary appraisal on community lodgeable status in Dalian using analytic hierarchy process and geographic information system software Surfer 8.0 unifies. Finally, by Peach, s differentiation degree conception, we could receive the polarization indexes of the community lodgeable, and the index is 27.6. The findings indicated that, the whole appraisal of the community lodgeable of Dalian is good; there is difference among the four downtown districts. The high lodgeable status areas are distributed in the eco- environmental scenic spots, the commerce activity centers and the administration centers.
Human being is the main body of infomationization, the rapid development of information technology has had a vital impact on personal communication network. Based on a survey of 12 cities and more than 2,000 questionnaires in Suzhou-Wuxi - Changzhou area, by using SPSS software and modeling methods, the paper analyses its evolution characteristics and principles of personal communication network under the influence of infomationization from three aspects: personal information sources, contact methods, contact frequency, and comes to some conclusions: The rate of traditional sources of information such as TV, newspapers is declining, while the rate of new sources of information like the Internet, celluar phones is increasing; On the personal contact methods, the traditional contact of geographic physical space is gradually declining, while telecommunication of virtual space is flourishing, and the latter has a strong dominant position etc. The paper indicates that the relationship between geographical physical space and network virtual space is not alternative but complementary and so on. The frequency of personal communication between the cities is increasingly more, and the amplitude of personal contact frequency index has a remarkably positive correlation with the rank of cities.
This paper analyzed a large number of investigation files, which come from the rural area of ten villages, Henan province. Result of this analysis indicated that the number and scale of rural households'migration employment is a synthetical outcome, which is affected by economic factors, family factors and environment factors. The Optimal Multiple Regression Model shows that several factors have a heavy influence on the migration employment of rural households in Henan province. First, there is a positive impact between the scale of migration employment and the benefit of migration employment, the cost of migration employment, the population statement of rural households, the expense of rural households, and so on. In addition, people who have junior high school degree will bring a forward- looking effect on the scale of migration employment, while senior high school degree or upwards will produce a negative effect on the scale of migration employment. Third, as far as the environment factors are concerned, we can get the conclusion that the development level of economy has a positive impact on the migration employment. Terrain, reachability and the land use style have a negative impact on the migration employment.
Some scholars have calculated ecological footprint using the theory of emergy analysis. But there are some drawbacks in their studies. This paper singles out the ecological footprint of cropland from 6 types of land use as study topic focusing on the regional differences in Jiangsu province, revises the ecological carrying capacity with productivity factor because land use efficiencies vary across regions, and uses ecological gap index (EGI) in place of ecological deficit or remainder to evaluate the ecological sustainability. In the research of ecological carrying capacity of cropland, the solar radiation, precipitation, soil fertility, the efficiency of land use and area of cropland are considered as natures of ecological carrying capacity, and a new concept of “standard area”is established in terms of the quality class of cropland. In Jiangsu province, ecological carrying capacity of cropland in northern region is more than that in the middle and southern regions, that is, Yancheng, Huaian and Suqian have the highest ones while those Wuxi, Nanjing and Suzhou are the lowest. Ecological footprint of cropland in southern region is less than that in the middle and northern regions, that is, Yancheng, Nantong and Huaian have the greatest ones while those Wuxi, Suzhou and Changzhou are the least. Ecological gap indexes of cropland of all 13 regions in Jiangsu are all lower than 0.5, which means croplands usees are unsustainable. Cropland’ s EGI in the middle part is lower compared with southern and northern parts, and the midst is better than the eastern and western districts in Jiangsu’s middle part. Suzhou and Wuxi have the highest EGI, and that Nantong and Yancheng have the lowest EGI. The results can be helpful for integrating the theory of emergy analysis to the conventional model of ecological footprint and for sustainable use of cropland in this province.
This paper works out port connection index and composite Gini coefficient so as to play a quantification analysis on evolution of port regional combination in Chang- Shan archipelagos from 1986 to 2004 based on research about evolution of port regional combination and consider that da - chang- shan port regional combination is always most important door - port and ports in Chang- Shan archipelagos are tend to concentrate. Then this paper plays an analysis on the projects of connection of island and land of Chang- Shan archipelagos, and on the spatial structure of port regional combination in above possible projects of connection of island and land of Chang- Shan archipelagos.
Gravity models are the basic tools which are widely applied in the research of spatial interaction (SI). It is well known that SI decreases as the distance increases or the mass decreases. The measurement and explanation on parameters are hot topics but the temporal variations of them are not discussed so frequently. This paper deals with how and why the parameters change with time by using the unrestrained gravity model and the data set consists of China's railway passenger flows between about 200 cities. We find that scale parameters show an increasing trend with a little fluctuation and distance - decay parameters grow over time instead of monotonic decrease over time. And an empirical and theoretical explanation will be given to why the general assumptions of monotonic increasing scale parameters and monotonic decreasing distance - decay parameters are not obeyed.
The paper elaborates the accessibility concept and application scope in the different disciplines simply, analyzes the factors influencing accessibility, summarizes quantification method used commonly at the present stage in geometry topology, points out application conditions and insufficiency of the gravity model, the distance model, the accumulation opportunity method. In this foundation, discovers that quantification limiting to the spatial criterion can not respond the relation of the spatial network accurately, in view of this question, proposes the quantification model basing on the time impedance function, which takes the main variable by the practice capacity. This model can respond the spatial demand intensity indirectly. Then the paper introduces the node importance concept，it can reflect factors influencing accessibility in the road network even more directly, such as society, economy, transportation. This model can make up for the insufficiency of space and time method.
Taking road network in Longitudinal Range- Gorge Region (LRGR) as an case study, we got the bound of road - effect zone through overlay method of GIS considering its influencing factors. Then we calculated the percentage of road- effect zone area in certain region and study the spatial variability in LRGR. Further, road density, population density, village number, ecological capacity and average altitude were selected to analyze their relationship with road effect zone. The results showed that different road types had various road- effect zones. Spatial contribution of road effect showed a great regional difference. The effect zone decreased from Kunming to region around. Honghe River Valley had a higher value than Lancang and Nujiang River Valley. In LRGR, there showed significant spatial convergence region in east, north and south - west of LRGR. Correlation analysis showed that there existed significant correlation between road- effect proportion and road density, population density, village number, ecological capacity while no correlation with average altitude.
