Table 2. Examples of Instruments for Measuring Methane (CH₄) and Carbon Dioxide (CO₂) Using the Satellite Methods Depicted in Figure 4^a.

method	instrument	gas	discussion	resolutionb spectral (nmc)d spatial (km2)	main reference
SWIR: Atmospheric Sensor	SCIAMACHY	CH4, CO2	Large spatial coverage and achieved first global mapping (2002–2012)	0.4, 1.4, 0.2	(Buchwitz, et al. 2005)
				30 × 60
	GOSAT	CH4, CO2	Fine spectral resolution, measures select global locations (2009–present)	0.02, 0.06, 0.10	(Kataoka, et al. 2017)
				10 × 10
	GHGSat	CH4, CO2	Constructed with a very fine pixel resolution to measure facility scale emissions. Claire (2016–present) Iris (2020–present)	0.1	(Jervis, et al. 2021)
				0.05 × 0.05
	TROPOMI	CH4	Can produce daily estimates of surface emissions of methane. (2017–present)	0.25	(Hu, et al. 2018)
				7 × 7
SWIR: Imaging Spectrometer	PRISMA	CH4, CO2	The first two main satellites launched using hyperspectral sampling. Attains fine pixel resolution. (2019–present)	10	(Cusworth, et al. 2019)
	EnMap			0.03 × 0.03
	EMIT	CH4, CO2	Will attain moderate pixel and spatial resolution. Data will be publicly available.	7.4	(Ayasse, et al. 2019)
				0.06 × 0.06
	Carbon Mapper	CH4, CO2	Will attain fine pixel and spatial resolution. Data will be publicly available. (Not launched yet.)	6	(Carbon Mapper)
				0.03 × 0.03
TIR	MethaneSAT	CH4, CO2	Intended for broad monitoring with point source estimation. Data will be publicly available. (Not launched yet.)	0.3	(Rohrschneider, et al. 2021)
				0.01 × 0.04
	TES	CH4	Achieved the smallest TIR pixel size with fine precision (2004–2011)	0.8	(Worden, et al. 2012)
				5 × 8
	IMG	CH4, CO2	Provided the first satellite sensing of methane (1996–1997)	0.1 cm–1	(Shimoda, Ogawa et al. 2000)
				8 × 8
	CrIS	CH4, CO2	Hyperspectral infrared sounding method with the best vertical resolution through the troposphere. (2011–present)	0.625 cm–1	(Nalli, et al. 2020)
				14 × 14
Lidar	Merlin	CH4	Intended to measure in dark conditions at a fine resolution. (Not launched yet.)	N/A	(Wührer, et al. 2019)
				200 μm

^aFull names of abbreviations: SCanning Imaging Absorption spectroMeter for Atmospheric CartograpHY (SCIAMACHY), Greenhouse gases Observing SATellite (GOSAT), Greenhouse Gas Satellite (GHGSat), TROPOspheric Monitoring Instrument (TROPOMI), PRecursore IperSpettrale della Missione Applicativa (PRISMA), The Environmental Mapping and Analysis Program (EnMAP), Technology Experiment Satellite (TES), Interferometric Monitor for Greenhouse gases (IMG), Cross-track Infrared Sounder (CrIS), Methane Remote Sensing Lidar Mission (Merlin).

^bWhen the instrument measures both CO₂ and CH₄ at varying spectral resolutions, resolution is given as band1, band2, and band3.

^cExcept where otherwise noted.

^dGiven as the full width at half maximum (FWHM).