Research On Aerosol Optical Depth Change Based On Interpolationmodel Of Beijing-Tianjin-Hebei Typical Region

Atmospheric aerosol usually refers to the tiny particles suspended in the atmosphere, particle size can range from 0.001μm to dozens of micron.The shortwave radiation and longwave radiation transmission process and precipitation process of atmospheric aerosol make it plays an important role in the earth’s atmosphere radiation balance and climate change. In recent years,atmospheric aerosols have become the main composition of the air pollution in many big and medium-sized cities.When the PM10 in Aerosol was ihaled, it can cause many diseases and affect human’s health. Although the ground-based monitoring site can perform on the aerosol particles, the sites are uneven distribution, which is difficult to monitor the temporal and spatial changes of the aerosol all-round, MODIS has unique advantages in the aerosol optical thickness monitoring and make up for the deficiency of the ground –based monitoring greatly.As one of the most basic of aerosol optical properties,Aerosol Optical Depth is a physical quantity to measure atmosphere aerosol particle’s absorption reflection scattering of solar radiation.Because the direct influence of the propagation in the atmosphere of solar radiation make AOD become a key factor determining the climate effects of aerosols, It often be used to study variations and regional climate effect of aerosol.But if Terra satellite encounters cloudy rain snow or other bad weather,it will unable to obtain remote sensing image on ground. And undeserved data processing will cause the shortage of some data.In this paper,data sources is the Terra Atmosphere Level 2 Products-MODIS/AOD(MOD04-L2).Scope of the study is Bejing-Tianjin-Hebei Region. Time scale is the annual October from 2009 to 2013 and the spatial resolution MOD04-L2 data is 1000 m.ARCGIS and ENVI as the technology platform,this article explores a new interpolated study way of remote sensing retrieved AOD missing values.According to geomorphological conditions of Bejing-Tianjin-Hebei Region,it is divided into six regions:Bashang plateau, Northwestern mountions of Bejing-Tianjin-Hebei Region, northeast mountains Bejing-Tianjin-Hebei Region, Taihang Mountains, coastal plain area and inland plains area. On the basis of the MODIS AOD data of October in 2009 and 2010 for two years,sample point data that are selected respectively in each region make daily regional average.According to the daily variation rule of AOD,we making seven standard interpolation principle,which are used to establish the times series trend line interpolation model obtaining the IDL programming language, so interpolation is out of the daily aerosol optical depth image in October of 2009-2013 year of Beijing-Tianjin-Hebei plain region.Compared with the original image,overall trend of interpolation results image is consistent, but there are a small part of obviously smaller or bigger results.Then on the basis of the daily aerosol optical depth image,and using one by one pixel average method,the article respectively calculated monthly average of AOD of the original image and the interpolation image of Bejing-Tianjin-Hebei plain region. Research has shown that in space the original image and interpolation image of AOD have basically the same change trend,which increase from the northwest to the southeast; In time AOD increased gradually since 2009, AOD of 2012 is the worst of five years,AOD declined in 2013; the highest difference of five years between the original image and interpolation image of AOD is 0.02.The difference is small,and the interpolation result is better.Finally this article extracted AOD of ten cities inside the plain area of Bejing-Tianjin-Hebei Region,and analyzed spatial distribution of AOD.The results showed that the high value city of the plain area of Bejing-Tianjin-Hebei Region are Handan City, Langfang City, Cangzhou City.These three cities draw a straight line,and the high value areas located in the southeastern region of this line including these three cities. Median value cities that are Langfang City, Tangshan City, Tianjin City, located mainly in northeastern region of the plain area of Bejing-Tianjin-Hebei Region.The city in west of the plain area of Bejing-Tianjin-Hebei Region including Xingtai City, Shijiazhuang City, Baoding City and Beijing City are the low value cities.