Abstract
We quantify the impact of atmospheric transport and limited marine boundary layer sampling on changes in global and regional methane burdens estimate using tracer transport model simulations with annually repeating methane emissions and sinks but varying atmospheric transport patterns. We find the 1σ error due to this transport and sampling effect on annual global methane increases to be 1.11 ppb/year and on zonal growth rates to be 3.8 ppb/year, indicating that it becomes more critical at smaller spatiotemporal scales. We also find that the trends in inter-hemispheric and inter-polar difference of methane are significantly influenced by the effect. Contrary to a negligible trend in the inter-hemispheric difference of measurements, we find, after adjusting for the transport and sampling, a trend of 0.37 ± 0.06 ppb/year. This is consistent with the emission trend from a 3-D inversion of the measurements, suggesting a faster increase in emissions in the Northern Hemisphere than in the Southern Hemisphere.
| Original language | English |
|---|---|
| Pages (from-to) | 2302-2311 |
| Number of pages | 10 |
| Journal | Geophysical Research Letters |
| Volume | 46 |
| Issue number | 4 |
| Early online date | 29 Jan 2019 |
| DOIs | |
| Publication status | Published - 28 Feb 2019 |
Funding
We acknowledge the support by the Netherlands Organization for Scientific Research (NWO) and Copernicus Atmosphere Monitoring Service (“CAMS_73 Greenhouse gases fluxes”). The TM5 model computations were carried out on the Dutch national supercomputer Cartesius maintained by SURFSara (www.surfsara.nl). NOAA CH4 measurements are freely available from NOAA's public ftp server (ftp://aftp.cmdl.noaa.gov/data).
| Funders | Funder number |
|---|---|
| Copernicus Atmosphere Monitoring Service | |
| NOAA's public ftp server | |
| Nederlandse Organisatie voor Wetenschappelijk Onderzoek |
Keywords
- atmospheric burden
- atmospheric transport
- CH emissions
- interhemispheric difference
- methane
- TM5
