Search

The regional economic discrepancy has always been acting as a very important part of the region-economy research. Taking county level of Baiyin as the study unit, the temporal characteristics of the regional economy disparity of Baiyin was analyzed through calculating the standard deviation, extreme difference, coefficient of variation and RHL of per capita GDP of different counties and districts from 1994 to 2008. Using the principal component analysis and cluster analysis, the spatial characteristics of the regional economic disparity of 2008 was also analyzed by constructing a comprehensive economic index system which includes fourteen economic indices. The results show: Firstly, the absolute discrepancy of regional economy of five counties (districts) shows an enlarging trend in Baiyin, and this trend mentioned above was speeded up espacially after 2003. The polarization of regional economy was becoming more and more obvious. The standard deviation and extreme difference of per capita GDP increased to 13646.70 yuan and 37007.00 yuan in 2008 from 2819.13 yuan and 7684.00 yuan in 1994 respectively, enlarging 3.84 times and 3.82 times respentively. Secondly, the relative discrepancy of regional economy slightly reduced in Baiyin in the last 15 years. Thirdly, based on the scores of comprehensive economic strength, three counties and two districts of Baiyin was divided into three types of economic areas, namely, more developed, middle developed and less developed.

Based on the observational data in Lanzhou and two other sites surrounding it from 1951 to 2010, this paper analyzes the surface air temperature changes of Lanzhou and its surrounding sites during the past 60 years by the surface air temperature Linear trends and the surface air temperature trend coefficient; this paper also study the changes of urbanization in Lanzhou by the changes of the population in Lanzhou for the past 60 years. We found that there is a close relation between surface air temperature change and urbanization development. There are distinct seasonal differences in effects of urbanization on surface air temperature change trend, and different effects of urban heat island are observed in different time periods. After 1984, the average surface air temperature trend coefficient of Lanzhou was more obvious than those of the surrounding sites; the changes trend is bigger than the value of before 1984, which indicating that the urban heat island effect increases with the increase of both the surface air temperature and the warming rate. We also found that the heat island effect of Lanzhou vary according to the season and month, the most significant warming trend occurs at all the three sites in spring, sequentially followed by spring, autumn and summer. Urbanization of Lanzhou had greater effect on the maximum surface air temperatures than on the minimum. The surface air temperature trend coefficient of the former is larger than the latter and the surface air temperature increasing trend becomes bigger after 1975.

Through changing ecosystem's internal structure and functiong, land use change has affected the supply of ecosystem services. Taking Lanzhou as a study area, this paper used the land use dynamic degree model and ecosystem service value evaluation model to analyse the characteristic of land use change and evaluate the ecosystem service value of Lanzhou from 1997 to 2005. And sensitivity index was introduced to verify the reliability of ecological value coefficient. The results show:Firstly,there were greater changes in the dissimilar land use types during the period of 1997–2005. The area of garden plot, forestland,residential land, industrial and mining land and traffic land increased. In contrast, the area of cultivated land,grassland,water region and unutilized land land decreased. Among which the changes of area and speed of residential Land and industrial and mining land were all the largest, with the land use dynamic degree of 18.15%, and its area changes to 119395.09 hm2 from 48689.79hm2 in the study period. Secondly, the ecosystem service value presented rising trend totally with the trend rate of 0.13%, which indicates that environmental effect by afforestation and conversion of cropland to forest has won initial success in Lanzhou.

Based on the climatic data of four meteorological stations from 1960 to 2009,using FAO Penman-Monteith model, ArcGIS IDW interpolation and Mann-Kendall test and T-test, the paper analyzes the changing trends,spatial and temporal differences and mutation characteristics of surface dry and wet conditions.The results show: Firstly, the overall trend of surface dry and wet conditions had been becoming wetter and wetter with the trend rate of humid index 0.006/10yr during the period of 1960-2009 in Shiyang River Basin.The surface was drier in the period of 1960s-1970s,and then became wetter after 1980s,especially after 2000.Secondly,the spatial differences of surface dry and wet conditions are significant.The mean annual humid index decreased from 0.404 of the upper reaches to 0.081 of the lower reaches gradually and the changing rates also changed from fast to slow. Furthermore, the lower reaches appeared the most dramatic fluctuation, followed by the upper reaches and the slightest fluctuation in the middle of river.Thirdly,the seasonal variations of surface dry/wet conditions were very different.The mean annual humid index was the largest in summer,followed by the autumn and the less in winter and spring.The overall changing trends of four seasons were all increasing,but the wetting trend was more significant in autumn and winter than that in spring and summer.Correlation analysis shows the correlation coefficients between summer, autumn,winter,spring and the mean annual were 0.665,0.591,0.397 and 0.334 respectively,which were all accepted for the 1% significance level,indicating the humid index increasing in the four seasons,especially for the two fomers, made greater contribution to the annual humid index changing.Finally,the mutation threshold of annual humid index occurred in the year around 1983,while the mutation years for the winter,spring and autunm were 1984,1981 and 1999 respectively and the unconspicuous mutation in summer.