Abstract
Abstract. Several satellites have been launched to monitor the increasing concentrations of greenhouse gases, especially CO2 and CH4 in the atmosphere, through backscattered hyperspectral radiance in the shortwave infrared (SWIR) band. The vertical profiles of greenhouse gases and aerosols could strongly affect the results from these instruments. To investigate the effects of the vertical distribution of CO2 on the uncertainty of SWIR satellite retrieval results, we conducted observations of the vertical profiles of CO2, CH4 and aerosol particles at 0.6–7 km above sea level using a Beechcraft King Air 350ER in Jiansanjiang (46.77∘ N, 131.99∘ E), Heilongjiang Province, northeast China, on 7–12 August 2018. The profiles from this aircraft captured a decrease in CO2 from 2 km to the minimum altitude due to the absorption of vegetation at the surface in summer. CH4 measurements showed about a 0.2 ppm increase from 2.0 to 0.6 km on 10 August, which may result from emissions from the large area of paddy fields below, and a constant mole fraction between 1.951 and 1.976 ppm was recorded at 2 km and above. Comparison of CO2 profiles from a new version of the carbon cycle data assimilation system Tan-Tracker (v1), retrievals from OCO-2 and aircraft measurements was conducted. The results from OCO-2 and the assimilation model system Tan-Tracker captured the vertical structure of CO2 above 3 km, whereas below 3 km the values from OCO-2 and the Tan-Tracker model were lower than those from in situ measurements. Column-averaged CO2 volume mole fractions calculated from in situ measurements showed biases of -4.68±0.44 ppm (-1.18±0.11%) compared to OCO-2 retrievals.
Highlights
Global warming due to greenhouse gases (GHGs) has become one of the most urgent and widely studied issues in recent years
The aircraft used for this experiment was a Beechcraft King Air 350ER, which is a twin-turboprop aircraft designed for weather modification missions and measurement of trace gases and aerosols by the China Meteorological Administration (CMA)
The CO2 concentration increased with height in the troposphere (Fig. 5a), which may result from CO2 uptake by rice plants near the surface during the summer growth season
Summary
Global warming due to greenhouse gases (GHGs) has become one of the most urgent and widely studied issues in recent years. The Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) noted that the global average temperature has increased by 0.85◦ over the period of 1880–2012. GHGs, especially the increasing CO2 levels in the atmosphere related to anthropogenic activities, are blamed for global warming, because they absorb and emit radiant energy within the thermal infrared range. Accurate measurement of CO2 concentrations and their spatial and temporal variations in the atmosphere is essential for estimation of sources and sinks in regional and global models (Patra et al, 2005a, b; Zhang et al, 2008). The Global Atmospheric Watch program (https://community.wmo.int/activity-areas/gaw, last access: 19 June 2020) coordinates the systematic observation and Published by Copernicus Publications on behalf of the European Geosciences Union
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
