A 15-year record of CO emissions constrained by MOPITT CO observations
Long-term measurements from satellites and surface stations have demonstrated a decreasing trend of tropospheric carbon monoxide (CO) in the Northern Hemisphere over the past decade. Likely explanations for this decrease include changes in anthropogenic, fires, and/or biogenic emissions or changes i...
| Main Authors: | , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-04-01
|
| Series: | Atmospheric Chemistry and Physics |
| Online Access: | http://www.atmos-chem-phys.net/17/4565/2017/acp-17-4565-2017.pdf |
| Summary: | Long-term measurements from satellites and surface stations have demonstrated
a decreasing trend of tropospheric carbon monoxide (CO) in the Northern
Hemisphere over the past decade. Likely explanations for this decrease
include changes in anthropogenic, fires, and/or biogenic emissions or changes
in the primary chemical sink hydroxyl radical (OH). Using remotely sensed CO
measurements from the Measurement of Pollution in the Troposphere (MOPITT)
satellite instrument, in situ methyl chloroform (MCF) measurements from the World
Data Centre for Greenhouse Gases (WDCGG) and the adjoint of the GEOS-Chem
model, we estimate the change in global CO emissions from 2001 to 2015. We show
that the loss rate of MCF varied by 0.2 % in the past 15 years,
indicating that changes in global OH distributions do not explain the recent
decrease in CO. Our two-step inversion approach for estimating CO emissions
is intended to mitigate the effect of bias errors in the MOPITT data as well
as model errors in transport and chemistry, which are the primary factors
contributing to the uncertainties when quantifying CO emissions using these
remotely sensed data. Our results confirm that the decreasing trend of
tropospheric CO in the Northern Hemisphere is due to decreasing CO emissions
from anthropogenic and biomass burning sources. In particular, we find
decreasing CO emissions from the United States and China in the past 15 years,
and unchanged anthropogenic CO emissions from Europe since 2008. We
find decreasing trends of biomass burning CO emissions from boreal North
America, boreal Asia and South America, but little change over Africa. In
contrast to prior results, we find that a positive trend in CO emissions is likely
for India and southeast Asia. |
|---|---|
| ISSN: | 1680-7316 1680-7324 |