In:
Atmospheric Chemistry and Physics, Copernicus GmbH, Vol. 22, No. 14 ( 2022-07-29), p. 9617-9646
Kurzfassung:
Abstract. We review the capability of current and scheduled satellite
observations of atmospheric methane in the shortwave infrared (SWIR) to
quantify methane emissions from the global scale down to point sources. We
cover retrieval methods, precision and accuracy requirements, inverse and
mass balance methods for inferring emissions, source detection thresholds,
and observing system completeness. We classify satellite instruments as area
flux mappers and point source imagers, with complementary attributes. Area
flux mappers are high-precision (〈1 %) instruments with 0.1–10 km
pixel size designed to quantify total methane emissions on regional to
global scales. Point source imagers are fine-pixel (〈60 m)
instruments designed to quantify individual point sources by imaging of the
plumes. Current area flux mappers include GOSAT (2009–present), which
provides a high-quality record for interpretation of long-term methane
trends, and TROPOMI (2018–present), which provides global continuous daily
mapping to quantify emissions on regional scales. These instruments already
provide a powerful resource to quantify national methane emissions in
support of the Paris Agreement. Current point source imagers include the
GHGSat constellation and several hyperspectral and multispectral land
imaging sensors (PRISMA, Sentinel-2, Landsat-8/9, WorldView-3), with
detection thresholds in the 100–10 000 kg h−1 range that enable
monitoring of large point sources. Future area flux mappers, including
MethaneSAT, GOSAT-GW, Sentinel-5, GeoCarb, and CO2M, will increase the
capability to quantify emissions at high resolution, and the MERLIN lidar
will improve observation of the Arctic. The averaging times required by area
flux mappers to quantify regional emissions depend on pixel size, retrieval
precision, observation density, fraction of successful retrievals, and
return times in a way that varies with the spatial resolution desired. A
similar interplay applies to point source imagers between detection
threshold, spatial coverage, and return time, defining an observing system
completeness. Expanding constellations of point source imagers including
GHGSat and Carbon Mapper over the coming years will greatly improve
observing system completeness for point sources through dense spatial
coverage and frequent return times.
Materialart:
Online-Ressource
ISSN:
1680-7324
DOI:
10.5194/acp-22-9617-2022
Sprache:
Englisch
Verlag:
Copernicus GmbH
Publikationsdatum:
2022
ZDB Id:
2092549-9
ZDB Id:
2069847-1