Spatiotemporal variations in mid-upper tropospheric methane over China from satellite observations

Abstract

Spaceborne measurements by the Atmospheric Infrared Sounder (AIRS) on the EOS/Aqua satellite provide a global view of methane (CH 4 ) distribution in the mid-upper troposphere (MUT-CH 4 ). The focus of this study is to analyze the spatiotemporal variations in MUT-CH 4 over China from 2003 to 2008. Validation of AIRS CH 4 products versus Fourier transform infrared profiles demonstrates that its RMS error is mostly less than 1.5%. A typical atmospheric methane profile is found that shows how concentrations decrease as height increases because of surface emissions. We found that an important feature in the seasonal variation in CH 4 is the two peaks that exist in summer and winter in most parts of China, which is also observed in in-situ measurements at Mt. Waliguan, Qinghai Province, China (36.2879°N 100.8964°E, 3810 m). Also, in the summer, only one peak existed in western and southern China since there are no more significant anthropogenic sources in winter than at any other time of the year.

Long-Term Trends of Atmospheric CH4 Concentration across China from 2002 to 2016

“…The potential change in sources of CH 4 emissions will greatly influence the CH 4 concentration in the atmosphere. However, few studies have been conducted to evaluate the long-term spatiotemporal variations of atmospheric CH 4 concentrations across China [20][21][22][23][24][25].…”

Space-borne observation of methane from atmospheric infrared sounder: data analysis and distribution over Iraq

“…The lowest value of CH 4 (1.759 ppmv) during the spring season (March-May) was appeared at the pristine desert environment at the west and the south-west region While the highest value (1.880 ppmv) appeared on May at the north and north east regions of Iraq. The mean and standard deviation of CH 4 for spring season was (1.834±0.0028 ppmv) which is the lowest during the entire period for the study area and the mean CH 4 Space-borne observation of methane from atmospheric infrared sounder from these sources [8], while the lowest values of CH 4 appeared at the pristine desert environment due to the winds which plays an important role in mixing gases and result into mitigate the concentration of CH 4 on height 800 meters at the rest parts of Iraq. In Iraq "Shamal winds" is the most predominant prevailing strong northwesterly wind; it is steady and blows from the north and northwest.…”

“…The remote sensing techniques (satellite measurements) were employed to study the spatiotemporal distributions and variations of CH 4 in various researches for different regions in the world, which provide some information and evidence of CH 4 sources and traces in the atmosphere [6][7][8].…”

Modulation of midtropospheric methane by El Niño

“…Zhang et al . [] used CH 4 data from the Atmospheric Infrared Sounder (AIRS) to study middle‐upper tropospheric methane and found that AIRS CH 4 agrees well with the Fourier transform infrared profiles in China [ Zhang et al ., ]. Xiong et al .…”

“…CH 4 measurements are available from many different satellites, including ADEOS, GOSAT, SCIAMACHY (Scanning Imaging Absorption Spectrometer for Atmospheric Chartography), AIRS (Atmospheric Infrared Sounder), and IASI [Clerbaux et al, 2003;Frankenberg et al, 2005;Frankenberg et al, 2006;Xiong et al, 2008;Razavi et al, 2009;Saitoh et al, 2012;Crevoisier et al, 2013;Xiong et al, 2013]. Zhang et al [2011] used CH 4 data from the Atmospheric Infrared Sounder (AIRS) to study middle-upper tropospheric methane and found that AIRS CH 4 agrees well with the Fourier transform infrared profiles in China [Zhang et al, 2011]. Xiong et al [2009] found a strong CH 4 plume in the middle troposphere during South Asia monsoon seasons (July-September), providing evidence of strong upward transport moving CH 4 from the surface to middle troposphere [Xiong et al, 2009].…”