The Temporal And Spatial Distribution Of CH4 Vertical Column Density Over China Bsaed On Satellite Remote Sensing Data

Methane (CH4) is an important trace atmospheric greenhouse gases in the atmosphere. And its concentration changes not only affect the radiation balance of the ground-gas system, but also play a very important role in tropospheric and stratospheric chemistry. The distribution of CH4 varies will influence the radiation effect, dynamic and chemical effects in the stratosphere, and further refer to the troposphere by their interaction. Concentrations of atmospheric CH4 have been surprisely rising during recent years, while the source and sink of CH4 and its variation are not completely knowed, and large uncertainties limit the budget of atmospheric CH4 limit the accuracy of climate-change projections, so it is particularly concerned in internation. Understanding of atmospheric CH4 concentration of temporal and spatial characteristics has a very important theoretical significance and important value for in-depth understanding of land-air circulation system, improving the balance of atmospheric CH4 sources and sinks, mastering of atmospheric CH4 changes at the regional scale.The varied of atmospheric CH4 sources over China are important for global CH4 research on climate-chage. Based on this, we focus on the analsis of CH4 distribution pattern and influenced factor by the vertical column density CH4 concentration product in tropospheric from SCIAMACHY, combined with natural data and socio-economic data et al from 2003 to 2005. The results of analysis on atmospheric CH4 column concentrations from 2003 to 2005 are showed that:(1) Regional and uneven charactical. The CH4 in atmosphere concentration in eastern coastal was higher than its concentration in middle and western. The maximun is showed in Hunan Jiangxi,Hubei,Anhui,Guizhou provience, then its huabei zone; At the same time, the minimum is showed over Tibet and Qinghai zone, especially in Tibet Plateau. And the results from eco-region are that:CH4 sichuan-basin> CH4 huazhong> CH4 huanan> CH4 xinan> CH4 dongbei> CH4 huabei> CH4 xibeineimeng> CH4 Tibet Plateau. And yearly mean increasing is the first over Sichuan Basin, while the concentration of atmospheric CH4 over Tibet Plateau is decreasing yearly, reaching-12.04ppb.(2) Yearly and seasonaly pattern. The atmospheric CH4 concentration is increasing yearly from 2003 to 2005, the highest atmospheric CH4 concentartion was showed in August and there were two inflection points in May and Octorber. The extern of atmospheric CH4 concentration was 16336.90ppb-1888.35ppb, the order was:CH4 summer> CH4 autumn> CH4spring> CH4winter.(3) From the land use type. The etmospheric CH4 concentration showed:CH4 construction> CH4 irrigation> CH4 forest> CH4 others> CH4 unuse> CH4 grass. And the degree of CH4 concentration over construction,irrigation and forest was 1775.57ppb-1776.62ppb, difference was about 1ppb; Moreover, the CH4 concentration over others (paddy and water et al) is 1773.12 ppb, the difference was 2.50 ppb with former; The CH4concentration over grass and unused land was 1723.44 ppb-1728.59 ppb, with the difference reaching 50 ppb, being low value.(4) There are more reasons for the regional spatial pattern of atmospheric CH4 over China, but the climate factors were dominant. The analysis revealed that NDVI,precipitation,temperature were manifest correlation with the atmospheric CH4 concentration, and the correlation were 0.713,0.697,0.629, respectively. At the same time, the UVB showed the negetive correlation with the atmospheric CH4 concentration and the correlation is -0.884. So, we can get that the role of UVB on the CH4 concentration was negetive wholly, although some reaseraches view plant can emit the CH4 under aerobic conditions and the UVB was the incentives and assited. In different seasons,different land use types and different geographical regions, that climate factors influence on atmosoheric CH4 concentration was varied. Such as, over Qinghai-Tibet Plateau being relatively low human activity, the temperature was the greast impact on the CH4 concentration of broad-leaved mixed forest and coniferous forest, explaining 49%,43% of the spatial distribution in growing season (June-September), while the sominant factors of this eco-region are rainfall and ultraviolet radiation (UVB) in non-growing season. But, the role of ultraviolet radiation was particularly obvious for alpine meadow.(5) Other factors. The effects of other various factors on column density of atmospheric methan showed that:industrial waste gas emissions from fuel combustion> Cities of the total garbage> natural gas consumption> Coal consumption>coke consumption, and the correlation coefficient was 0.788,0.348,0.339,0.184,0.159, respectively. So, industrial gas emission was the main atmospheric CH4 source, municipal waste and natural gas was second. And the fossil fuels burning foucused in the higher population density, relative scarcity of coal energy zone improved the atmospheric CH4 concentration value, for example:Shan dong, Jiangsu and Anhui et al, while ruminant animals CH4 emission uplift the atmospheric CH4 concentration value for Henan provience. In addition, the wind speed and direction can educe the concentration of atmospheric CH4 value in western and elevate the atmospheric CH4 concentration value of the eastern region.