Remote sensing of the urban heat island and its changes in Xiamen City of SE China

World-wide urbanization has significantly modified the landscape, which has important climatic implications across all scales due to the simultaneous removal of natural land cover and introduction of urban materials. This resulted in a phenomenon known as an urban heat island(UHI). A study on the UHI in Xiamen of China was carried out using remote sensing technology. Satellite thermal infrared images were used to determine surface radiant temperatures. Thermal remote sensing data were obtained from band 6 of two Landsat TM/ETM\++ images of 1989 and 2000 to observe the UHI changes over 11-year period. The thermal infrared bands were processed through several image enhancement technologies. This generated two 3-dimension-perspective images of Xiamen's urban heat island in 1989 and 2000, respectively, and revealed heat characteristics and spatial distribution features of the UHI. To find out the change of the UHI between 1989 and 2000, the two thermal images were first normalized and scaled to seven grades to reduce seasonal difference and then overlaid to produce a difference image by subtracting corresponding pixels. The difference image showed an evident development of the urban heat island in the 11 years. This change was due largely to the urban expansion with a consequent alteration in the ratio of sensible heat flux to latent heat flux. To quantitatively compare UHI, an index called Urban-Heat-Island Ratio Index(URI) was created. It can reveal the intensity of the UHI within the urban area. The calculation of the index was based on the ratio of UHI area to urban area. The greater the index, the more intense the UHI was. The calculation of the index for the Xiamen City indicated that the ratio of UHI area to urban area in 2000 was less than that in 1989. High temperatures in several areas in 1989 were reduced or just disappeared, such as those in old downtown area and Gulangyu Island. For the potential mitigation of the UHI in Xiamen, a long-term heat island reduction strategy of planting shade trees and using light-colored, highly reflective roof and paving materials should be included in the plans of the city planers, environmental managers and other decision-makers to improve the overall urban environment in the future.

Spatio-temporal Variation of Landscape Heterogeneity under Influence of Human Activities in Xiamen City of China in Recent Decade

Xiamen is an economically competitive and highly urbanized city along the coastal area of Fujian Province, China. The research on spatio-temporal variation of landscape heterogeneity under the influence of human activities is of great importance to the further study on the relationship of landscape pattern and ecological process. It is also crucial to the discovery of spatial variation and intensity distribution of human activities. The research analyzed the intensity of human impacts and the spatial variation features and dynamics of landscape patterns by introducing statistical theories and approaches. We analyzed spatio-temporal variation of landscape heterogeneity using the geostatistical techniques, such as semivariogram and Kriging interpolation.Results show that there is a higher correlation between landscape heterogeneity indexes and human impact index. Both the indexes show a moderate spatial autocorrelation as well as an obvious characteristic of anisotropy. From 1998 to 2008, the spatial differentiation of the changes in the intensity of human activities and the changes in landscape heterogeneity shows that the landscape patterns in Xiamen are closely related with the urban land utilization methods, the condition of traffic and geographical location and the physical geographical condition such as the terrain and the ecological environment. The process of urbanization has a significant impact on the urban landscape pattern.

Analysis on the situation and countermeasures of water resources supply and demand in the cities of small and medium-sized river basins along southeast coast of China-taking Xiamen City as an example

The small and medium-sized river basins along southeast coast of China hold comparatively abundant water resources.However,the rapid resources urbanization in recent years has produced a series of water problems such as deterioration of river water quality,water shortage and exacerbated floods,which have constrained urban economic development.By applying the principle of triple supply-demand equilibrium,this paper focuses on the estimation of levels of water supply and demand in 2030 at different guarantee probabilities,with a case study of Xiamen city.The results show that water shortage and inefficient utilization are main problems in the city,as the future water supply looks daunting,and a water shortage may hit nearly 2×10^(8)m^(3)in an extraordinarily dry year.Based on current water supply-demand gap and its trend,this paper proposes countermeasures and suggestions for developing and utilizing groundwater resources and improving the utilization rate of water resources,which can supply as a reference for other southeast middle-to-small-sized basin cities in terms of sustainable water resources and water environment protection.

Study on the Dry Island Effect in Xiamen City

Using relative humidity data from two meteorological stations in Xiamen and absolute humidity calculated from temperature and water vapor,the annual,seasonal and monthly change characteristic of relative humidity and absolute humidity were comprehensive analyzed.Then the dry island effect of Xiamen city was studied.The result demonstrated that because of unique geographical features,the air humidity showed different change rules between urban and suburb.There was no obvious dry island effect in urban and suburb at last century.The change trend of average air humidity was unapparent before 90th of last century.From early 90th of last century,the air humidity in suburb began to decrease obviously.There was dry mutation for these two stations in 1993 and 2004 respectively.From the beginning of early of this century,both areas became dry obviously.The seasonal average relative humidity of Tongan station decreased each season,but what in Xiamen station changed unapparent.The seasonal average absolute humidity of Tongan station decreased apparently in spring and summer,but what did not change obviously in autumn and winter.The seasonal average absolute humidity of Xiamen station decreased apparently in summer,but what did not change apparently in other seasons.As respect from climate change of air humidity of each time,it decreased obviously at all four times at Tongan station.Relative humidity diminished most apparently at 8 and 20 o'clock.Absolute humidity diminished most apparently at 14 o'clock.For Xiamen station,relative humidity diminished most apparently at 14 o'clock.Absolute humidity diminished most apparently at 2 and 20 o'clock.

Xiamen,A Livable City

People say the best way to know the layout of a city is to see it from the sky.Seen from the sky,Xiamen is circled entirely by water,newly built buildings standing in order like toy bricks.With new architecture,a well arranged layout and adjacent waters,Xiamen represents distinct characteristics of China's newly uprising cities.

应用3S技术研究厦门市森林生态网络布局

该文探讨了3S技术在厦门市森林生态网络体系中的应用方法和手段,从整体上提高了厦门市生态环境建设的水平。本文可为相同自然条件和社会务件的城市森林生态建设提供参考。

Comparison of inorganic chemical compositions of atmospheric TSP,PM10 and PM2.5 in northern and southern Chinese coastal cities

To compare the inorganic chemical compositions of TSP（total suspended paniculate）,PM10（particulate matter with an aerodynamic diameter less than 10 μm） and PM2.5（particulate matter with an aerodynamic diameter less than 2.5 μm） in southern and northern cities in China,atmospheric particles were synchronously collected in Dalian（the northern city）and Xiamen（the southern city） in spring and autumn of 2004.The mass concentrations,twenty-three elements and nine soluble ions were assessed.The results show that in Dalian,the mass concentrations of Mg,Al,Ca,Mn and Fe in spring were 4.0-10.1,2.6-8.0,4.1-12,1.2-3.6 and 2.9-7.9 times higher,respectively,than those in Xiamen.The dust storm influence is more obvious in Dalian in spring.However,in Xiamen,heavy metals accounted for 13.9%-17.9%of TSP,while heavy metals contributed to 5.5%-9.3%of TSP in Dalian.These concentrations suggest that heavy metal pollution in Xiamen was more serious.In addition,the concentrations of Na＋,Cl-,Ca2＋ and Mg2＋ were higher in Dalian due to the influence of marine aerosol,construction activities and soil dust.The NO3-/SO42- ratios in Dalian（0.25-0.49） were lower than those in Xiamen（0.51-0.62）,indicating that the contributions of vehicle emission to particles in Xiamen were higher.Coefficient of divergence values was higher than 0.40,implying that the inorganic chemical composition profiles for the particles of Dalian and Xiamen were quite different from each other.