Xiangzheng Deng

The patterns and driving forces of urban sprawl in China

Along with its economic reform, China has experienced a rapid urbanization. This study identified the urban sprawl patterns in China using high-resolution Landsat Thematic Mapper and Enhanced Thematic Mapper data of 1989/1990 and 1999/2000, and analyzed the sprawl patterns during 1990-2000. Our results show that Chinas urban land increased by 817 million hectares. It was also found that Chinas urban sprawl had high spatial differences: such four sprawl patterns as concentric, leapfrog, linear and multi-nuclei, and their combinations coexisted. Case studies of the thirteen super cities showed that urban sprawl had been largely driven by demographic change, economic growth, and changes in land use policies and regulations.

Drought Monitoring in Northern China based on Remote Sensing Data and Land Surface Modeling

In this paper, agricultural and hydrological drought definitions are adopted to estimate the severity of drought in northern China in recent years. Particularly crop transpiration as important parameter is added in the drought index algorithm. Land surface model Noah are used and driven by a combination of meteorological reanalysis dataset (NCEP GDAS) and high resolution precipitation (CMORPH) and surface parameters from satellites (MODIS). The seasonal or yearly surface parameters (such as Albedo and LAI) from climatology are replaced by monthly data derived from MODIS, in order to represent the vegetation dynamics more accurately. Products for Crop transpiration and soil evaporation are derived at passing time of MODIS satellites. Temperature products of MODIS are adopted and are validated by simultaneous observation data of Dongping lake in Shandong province of China. Using vegetation transpiration (LEv) and latent evaporation (LE0= Rn-G) with high every 3 hours time resolution and 1km space resolution in north China, plant water stress index (PWSI) can be got. It is feasible that a combination of the land surface models and the two sources ET remote sensing model to monitoring drought using PWSI drought index according to the application of the method in North China.

Interpolating the Information of Site-based Soil Organic Carbon Stocks into Surface: a Case Study in the North China Plain

It is of great significance to understand the spatial variability of soil organic carbon (SOC) stocks of North China Plain which is one of the most important grain production bases in China. In this paper, we use Kriging interpolation method to generate a surface using the site-based SOC stocks in North China plain and then analyze the spatial variability of carbon SOC stocks. The surface data on the SOC stocks offers the one of the most important reference information to support the carbon management.

Critical controlling of PRED system of oasis ecology in the arid region of central Asia: a case study of Keriya River Valley oases, Xinjiang

Oases is a special ecosystem formed in arid climate and hungriness environment, in which resident, water and soil are the principal factor and exchanges of materials, energy and information are the main functional characteristics. The oases regions in central Asia are not only the basilic cradle of civilization of human beings, but also the important strategic places in world growing awareness of the potential benefits. We choose Keriya River Basin oases in south of Xinjiang as a case to study critical controlling of Oases Evolution, Based on the theories and methods used for environmental geology, physical geography, land resource research, and oases ecology. This study try to indicate the essential factors driving the oases ecosystem and the interactional dynamic mechanism in different scales and levels, confirm the optimal equilibrium aggregate of harmonious development between Population, Resources, Environment and Development, and establish the critical controlling pattern of sustainable development. We advance the indicator system to research the evolution of the PRED System of oases in Keriya River valley oases, in basis of the information derived from the field investigation and local materials. According to inquisitional result based on technical support of Geographic Information System (GIS) and Remote Sense (RS), the comparisons and analyses are carried out in land use at the upper reaches, vegetation change in the middle reaches, and desertification at the lower reaches, which narrates the regulations of Keriya River Valley oases land cover dynamic change. The main land cover types represent distinct characteristics of the local place. On the basis of field survey and statistical data, we use ARCINFO software to preprocess these data and the 2 TM satellite images. Through analyzing these images resulting from post-classification compare, we sums up the concrete quantificational dynamic distributed data of 13 land types covering a span of 15 years and regulation of the local ecological environment system. It finally points out that the trend of Keriya River Valley oases desertification expansion is mainly related to two important reasons: impact of natural environment and impact of human activities. In order to improve the local ecological environment, people inhabited this

Intercomparison of two trapezoid-based soil moisture downscaling methods using three scaling factors

ABSTRACT This paper compared two soil moisture downscaling methods using three scaling factors. Level 3 soil moisture product of advanced microwave scanning radiometer for EOS (AMSR-E) is downscaled from 25 to 1u2005km. The downscaled results are compared with the soil moisture observations from polarimetric scanning radiometer (PSR) microwave radiometer and field sampling. The results show that (1) the scaling factor of normalized soil thermal inertia (NSTIs) and vegetation temperature condition index (VTCI) are better than soil evaporative efficiency in reflecting soil moisture; (2) for method 1, NSTIS is the best in the downscaling of soil moisture. For method 2, VTCI is the best; (3) no significant differences of the correlation coefficients (R2) and the biases were found between the two methods for the same scaling factors. However, method 2 shows a better potential than method 1 in the time-series applications of the downscaling of soil moisture; (4) compared with the relationship between the area-averaged soil moisture of AMSR-E and that of PSR, R2 of the 6 sets of the downscaled soil moisture almost do not decrease, which suggests the validity of the downscaling of soil moisture with the two downscaling methods using the three scaling factors.

An Evapotranspiration Assimilation Method Based on Ensemble Kalman Filter and À Trous Wavelet

It is challenging to assimilate the evapotranspiration product (EP) retrieved from satellite data into land surface models (LSMs). In this paper, a perturbed ensemble Kalman filter (PEKF) and a trous wavelet transform (AWT) integrated method are proposed to implement the evapotranspiration assimilation. In this method, the AWT is used to decompose the EPs into multiple channels since it is very powerful in fusing high frequency spatial information of multisource data, and then the Kalman filter is performed in the AWT domain. The proposed method combines the advantages of the PEKF that is capable of accommodating model error and observation error, and the AWT can effectively perform multiresolution fusion. Assimilation experiment conducted with the Noah model and the EP retrieved from the MODIS data shows that the proposed method performs better than the traditional ensemble Kalman filter (EnKF) and PEKF methods. The analysis results fit well with the evapotranspiration observation at two field sites with different land surface conditions. These indicate that the proposed method is promising for assimilating regional scale satellite retrieved EP into LSMs.

Assessment of Suitability of Land Uses using a Multi-Source Information Fusion Method: A Case Study in the Hilly Area of Shandong Peninsular of China

Land is one of the most important natural resources. The assessment of the current land use pattern suitability can help people make good use of the natural resources. In this paper, the land-use suitability index (SI) is used to evaluate the suitability of the land use pattern in the hilly area of Shandong Peninsular of China. Land use data is derived from Landsat TM/ETM acquired in 1988 and 2000 using the multi-source information fusion method. The results indicate that, the land-use suitability is slightly improved from 1988 to 2000 and the corresponding SI-values changed from 0.77 to 0.80. The difference value of land-use suitability is only 0.03, not as large as people previously predicted.

Predicting Soil Organic Carbon Dynamics Under Various Scenarios using Data Assimilation Strategy: a Case Study in the North China Plain

It is of great significance to predict soil organic carbon (SOC) stock of North China Plain which is one of the most important grain production bases with wheat-corn rotation as its main cropping system in China. In this study, a data simulation strategy is developed to predict SOC stock which is featured by the syntheses of two models, Estimation System for Agricultural Productivity (ESAP) and the spatial explicit SOC decomposition model. Model-based simulation indicates that the SOC stock in the agricultural soils of North China Plain would change in a nonlinear trend in the next two decades.

Scenario analyses of the landscape change in the loess plateau: a case study of Qingyang Prefecture, China

Using the remotely sensed data from the interpretation of Landsat TM/ETM digital imagines, this paper analyzes the landscape changes of Qingvang prefecture since the mid-1980s by means of spatial analysis technologies, and further analyzes and identified different types of driving factors affecting the evolvement of ecosystem. Based on the area percentage data of ecological types in 2000, the spatiotemporal pattern of landscape change in Qinyang prefecture in 2005, 2010 and 2015 were simulated separately and the law and features of the change of ecosystem within the study area during the period of 2005-2015 was analyzed based on the simulation. The conclusion of this study is of significance on the decision making on the environmental protection and land use planning, rational exploitation of water and soil resources and implementation of sustainable development strategies in the watershed of the Loess Plateau.

Monitoring and assessment of landscape change in the minjiang watershed, the upper reaches of Yangtse River

Minjiang River is one of the major branches of Yangtze River where the forest resources abound. But the excessive logging and over-grazing has resulted in the destruction of the landscape, the reduction of ecological function of forest system in controlling soil erosion, the loss of biodiversity, the frequent occurrence of natural disasters such as mud-rock flow and landslide, and the more and more severe in desertification, and a severity to the ecological environment in the whole Yangtze River basin. This paper, based on the Landsat TM/ETM sensor data, analyzes the dynamic succession of the landscape pattern in Minjiang river watershed during 1985-2000 using the GIS spatial techniques. By tracking the change of landscape ecological indexes, this paper identified the succession of landscape pattern in the upper reaches of Minjiang River from 2005 to 2015. The findings of this study offers some valuable information on formulating the ecosystem protection planning and land use planning, exploiting rationally the water and land resources, and implementing the sustainable development strategy.