Temporal and spatial characteristics of atmospheric methane in the Yangtze River basin and the analysis of the main environmental impact factors

Methane (CH4), a significant atmospheric trace-gas, controls numerous chemical processes and species in the troposphere and stratosphere and is also a strong greenhouse gas with significantly adverse environmental impacts. Since the SCIAMACHY on the Envisat was in orbit since 2002, CH4 measurements at a regional scale became available. This study ( 1) firstly improved the spatial resolution of 0.5 degrees x0.5 degrees lat/lon grid data provided by University of Bremen IUP/IFE SCIAMACHY near-infrared nadir measurements using the scientific retrieval algorithm WFM-DOAS to 0.1 degrees x0.1 degrees lat/lon with the ordinary Kriging method, ( 2) then analyzed the spatial-temporal characteristics of atmospheric CH4 concentration in the Yangtze River basin (YRB), China from 2003 to 2005,( 3) finally analyzed the relations with the main environmental factors: the precipitation from GSMaP MVK+ 0.1x 0.1 lat/lon degree grid data and the temperature from 147 meteorological stations in the YRB. The analysis shows that atmospheric methane concentration has significant and obvious characteristics of the spatial distribution of the inter-annual cycle fluctuations and seasonal characteristics during the year, and points out that the temperature is the main impact factor.