| Land is a place for human activities and an important natural resource,which is affected by human activities and natural environmental factors.Many factors including global warming,environment deterioration,forest being massively destroyed,urban expansion and the loss of biodiversity,are giving unprecedented pressure to land.Land use is experiencing huge changes and these changes will impact fiercely on the climate and the environment around us.In China,the country which is experiencing rapid development,the relationship between the continuous expansion of urban construction land and urban heat island is a very important issue to study.Hubei province is located in the central region of China,it is a province with large population and essential to the economy of the whole China.Hubei is given much importance and focus by Chinese government.As the national strategy of"The rise of central China",the "two type society" construction plan and the comprehensive reform experiment of the urban agglomeration around Wuhan city implemented the regional land use change is worth noting,the corresponding climate change and its effect need to be studied.Wuhan is a city which is typically burning hot in summer".In order to establish a suitable living environment,to explore the relationship between urban heat island and other factors is especially necessary.In this study,the spatial distribution of land use data obtained by remote sensing interpretation is analyzed firstly.The single dynamic attitude of land use,comprehensive dynamic attitude of land use,land use degree and other techniques are used.The analysis tools such as spatial autoregressiveness,spatial hotspot,and spatial anomaly are also conducted.The regression equation is established by using Baidu index and land use change data,and the spatial distribution law is studied and the relationship between them is established.Secondly,the Hubei province meteorological site monthly data are captured.Five indexes-the annual average temperature,annual average heat value,the annual average temperature,minimum year accumulative rainfall and relative humidity index-were selected.The data which don’t obey normal distribution are under the Box-Cox data transformation to make it qualified,and then the interpolation of kriging model was also conducted to get the meteorological spatial distribution of the whole Hubei province.The meteorological data and socio-economic data obtained from Hubei Statistical yearbook are used,component analysis(PCA)is conducted to analyze the impact on land use change.Then,on the basis of analyzing the temporal trend and spatial distribution characteristics of climate change,the influence of land use change on climate is studied.When studying the impact of land use change on urban heat-island effect,ARIMAX model is adopted to study the time series relationship between this heat-island effect and land surface temperature(LST)when normalized difference vegetation index(NDVI)and monthly average land surface temperature are set as input variables.Meanwhile,the impact of construction land change on heat island is also studied.The main contents and conclusions are as follows:(1)The characteristics of land use change were studied on the base of single dynamic attitude of land use change,comprehensive dynamic attitude of land use change,land use degree,hot spot of land use change and outlier point,and the influence of policy factors on land use change was also studied.The overall land use situation of Hubei province is that the cultivated land covers across the whole province,the forest land is mainly concentrated in the west region and around the edge of Hubei Province.The waters is mostly located near the rivers in center and south region.A large number of non-construction land use types have been converted to construction land,and the urban scope has expanded dramatically.On the whole,the change of land use type in the central region near Wuhan shows a large dynamic attitude towards comprehensive land use change,which decreases with the increase of distance.The land use degree of Hubei province is positive on the whole,and the land use of the whole province presents a trend of continuous development.The unused land is around the riverbank zone,and the construction land is mostly in the large and medium-sized cities.The changes of cultivated land,forest land and construction land are highly correlated with the policies.(2)Based on principal component analysis,13 indicators are selected from 36 change is the major one,while the impact of natural factors such as climate is the minor one.The cultivated land is negatively correlated with the social economic factors but is in the positive correlation with the climate factors.Forest land change is negatively correlated with both the social economic factors and natural factors,the grass land is negatively changed corresponding to the social economic factors,while it is positively correlated with the natural factors,construction land are presenting a consistent trend with both of social economic factors and natural factors.(3)Based on the Kriging model,the annual mean temperature,annual mean maximum temperature,annual mean minimum temperature,annual cumulative precipitation,annual mean relative humidity and their spatial distribution were interpolated from the data of national and local stations in Hubei province from 1990 to 2015.The results show that the average annual temperature,maximum temperature and minimum temperature in the study period show an overall rising trend,which has slowed down in recent years,and the precipitation and wetland have declined somewhat,but the change range is not very big.In terms of spatial distribution,the temperature in the south and east is relatively high on the whole,but it is relatively high in Yichang.The precipitation is mainly in the south,the southeast and the southwest are areas with relatively high precipitation,and the humidity is relatively high in the south along the river and less in the north.On the whole,the impact of land use on climate is mainly the elevation of the lowest surface temperature,while the third region has the greatest impact,and the change of land use in the third region is closely related to the change of the highest temperature in this region.(4)ARIMAX model analyzes the heat-island effect in Wuhan and Yichang,heat-island effect is found in both these two cities.The heat-island effects in these two cities are both positively correlated with NDVI and monthly average temperature,but the influence degree is different.The heat-island effect and the NDVI in Yichang exists a 3 order lag,which is 5 order lag in Wuhan.The construction land in Wuhan and Yichang has a great influence on the urban heat-island warming,and the influence of construction land of the two cities on the surface temperature has a plateau period,and the change in Yichang is more significant. |
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