Spatial-temporal Variation Of Impervious Surface And Its Environmental Response In Guanzhong Area

The Guanzhong area is located at the important origin of the Chinese civilization.After the Guanzhong Plain urban agglomeration is rosed to a national-level urban agglomeration,the rapid development of urbanization will lead to the expansion of the impervious surface of the Guanzhong area inevitably.Quickly and accurately monitoring the dynamic changes of impervious surface,studying the regular and dynamic characteristics of impervious surface expansion,and quantitatively analyzing the environmental response of impervious surface expansion will provide reference for the optimization design,planning and development of impervious surface in Guanzhong area.The article uses the Landsat series satellite data of 45 sceneries in the Guanzhong area in 2000,2004,2009,2015 and 2020 to extract the impervious surface,then systematically analyze the temporal-spatial dynamic characteristics of impervious surface.At the same time,92 sceneries MOD11A2 which is land surface temperature product data and 730 sceneries MOD19A2 which is aerosol optical depth product data of the Guanzhong area of every year in 2000,2004,2009,2015 and 2020 are download and they are using to quantitatively analyze the environmental response of temporal-spatial variation of impervious surface in the Guanzhong area.(1)The article proposes a new ratio of impervious surface index(RISI).The RISI can extract the impervious surface of a large area accurately and distinguish soil well,but the accuracy of identifying bright sand is not good.The article combines support vector machine supervision and classification to eliminate sand,and proposes a method that is combination RISI and support vector machine to extract impervious surface.Using this method to extract the impervious surface of five stage in Guanzhong area,the overall accuracy is over 90%,the method can distinguish soil and sand well.(2)Temporal-spatial variation of impervious surface.The impervious surface of the Guanzhong area has increased from 783.55 km~2 in 2000 to 3924.58 km~2 in 2020,and the proportion of impervious surface has increased from 1.41%in 2000 to 7.08%in2020.During the research period,the impervious surface is concentrated in the southeast of the Guanzhong area,along the northeast-southwest direction distribution.The impervious surface mainly expands in the three directions of north,northeast and west,while the expansion of the south and southeast is slower.The barycenter of impervious surface has always been in the eastern part of the regional center of gravity,but it has a tendency to move to the west.High-density areas of impervious surface are accumulated continuously,over time,a large number of low-medium-density areas appear.The landscape pattern index shows that proportion of impervious surface landscape is increasing,patch density continues to increase,while patch shapes become more complex and diverse,and concentration of the largest patch on impervious surface continues to increase.(3)Environmental response of temporal-spatial variation of impervious surface.temperature response.The annual average land surface temperature in Guanzhong area is fluctuant.Distribution area of the low temperature zone and the medium temperature zone is getting smaller,while the sub-high temperature zone and the high temperature zone is getting larger.The percentage of impervious surface is positively correlated with the annual average land surface temperature by a power function;the impervious surface density is linearly positively correlated with the annual average land surface temperature.The landscape shape index(LSI)of the impervious surface has the closest relationship with the annual average land surface temperature.With the accumulation of impervious surface increasing,aggregation index(AI)of impervious surface has the stronger correlation with the annual average land surface temperature.Aerosol optical depth response.The annual average aerosol optical depth in the Guanzhong area is reduce overall,and spatial distribution is different in different years.The percentage of impervious surface is positively correlated with the annual average aerosol optical depth in a power function;the impervious surface density has a low correlation with the annual average aerosol optical depth.The landscape shape index(LSI)of the impervious surface has the closest correlation with the annual average aerosol optical depth.With the accumulation of impervious surface increasing,the correlation between aggregation index(AI)of impervious surface and the annual average aerosol optical depth becomes stronger.