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  • Product Sheet: Methane emission monitoring

Methane emission Monitoring

Image credit: ESA

PRODUCT DESCRIPTION

Category

Component products

Air Quality

N/A

Uses

  • Environmental monitoring - baseline historic mapping of environment and ecosystems
  • Environmental monitoring - continuous monitoring of changes throughout the lifecycle

Geo-information requirements

  • Air quality and emissions
  • Distribution and status of assets
  • Detailed land cover information

Description

Atmospheric methane (CH4) is the second-most abundant anthropogenic greenhouse gas (GHG) after CO2. During shale gas field development, unexpected emissions of methane and other light gases can occur. Knowledge of background and industrial emissions helps to meet emissions guidelines. For example, in the USA, the Environmental Protection Agency (EPA) regulates emissions from the oil and gas sector, and methods are issued for in situ measurement.

Satellite EO-based quantification of methane in the troposphere is a new area of research. Airborne hyperspectral systems, such as: MAMAP, AVIRIS-ng, HyTES, and CARVE demonstrate the future potential. Several EO sensors have been tested.  The SCIAMACHY instrument on board the ENVISAT satellite acquired CH4 monitoring data for seven years, and was a ground-breaking technology development platform. The sensor estimated total CH4 quantity of the at-nadir atmospheric column through modelling based on direct measurements of short-wave infrared (SWIR) radiation. Overall, the research reveals limitations in methane retrievals and deviations from validation data, as well as the relatively coarse spatial resolution of the observations (individual SCIAMACHY pixels are 30 km × 60 km, while some derived models average the data to a regular 1° longitude × 1° latitude grid).

The newer, operational TANSO Fourier Transform Spectrometer (FTS) sensor on board the Japanese Greenhouse Gases Observing SATellite (GOSAT) is dedicated to greenhouse gas monitoring. TANSO-FTS operates in the SWIR and thermal infrared (TIR) regions of the electromagnetic spectrum. SWIR measurements allow for the retrieval of CH4 column concentrations with high sensitivity near the Earth’s surface.

In 2015, a novel instrument operating in the SWIR region will be launched aboard the GHGSat nanosatellite. It will have unprecedented spatial resolution (tens of meters) and sensitivity equal to or better than any existing or previous SWIR satellite instruments.  Using a novel observational paradigm, the GHGSat instrument will retrieve both total CH4 values (through depth of atmosphere columns) and local emission rates for identifiable CH4 emission sources. GHGSat will also measure CO2 emissions.

In 2017 a new EO system dedicated to methane monitoring will be launched. The Methane Remote LiDAR Mission (MERLIN) Integrated Path Differential Absorption (IPDA) LiDAR will measure total-column CH4 with high accuracy, and represents a new approach to atmospheric monitoring – MERLIN will be a micro-satellite launched into a polar orbit by DLR and CNES. Mission planners expect CH4 concentration measurements at better than 2% error, even under cloudy or variable illumination conditions. In contrast to existing passive remote sensors, measurements in polar regions will be possible and biases due to aerosol layers and thin ice clouds will be minimised. Further, the LiDAR instrument will allow retrieval of methane fluxes in all seasons and at night time.

Methane emissions can be attributed to different sources (e.g., livestock, oil and gas, and mining) and are also dependent on land cover type, and are particularly affected by wetlands. Wetland extent and land use information can be used to improve the accuracy of methane emission maps.

The methane emissions monitoring product can currently deliver archived and operational regional scale methane estimates (raster image values) along with summary statistics. Significant short-term improvements in accuracy are expected due to the scheduled launch of new sensors and the development of new operational analytical methods.

Known restrictions / limitations

  • EO estimates of CH4 from SCIAMACHY (satellite decommissioned in 2012) yield small differences between minimum and maximum values, complicating analysis efforts. Further, estimation error magnitude is similar to the variability in the greenhouse gas mixing ratio being measured.
  • Spatial resolution of methane retrievals from satellite-based EO are currently relatively coarse – native resolution of sensors is around 10 km (GOSAT) to 30 km (SCIAMACHY) or more. Models may average the data to a regular 1° longitude × 1° latitude grid.
  • Future systems, such as GHGSat and MERLIN, should provide improved retrievals. Short wave infrared (SWIR) measurements from GHGSat will be in the tens of metres. The novel LiDAR system on the MERLIN satellite will be dedicated to CH4 monitoring and will provide data with 50 km resolution. Both systems will measure CH4 abundance with an accuracy of about 1-2%.

Lifecycle stage and demand

Pre-license

Exploration

Development

Production

Decommission

**

**

**

****

 

Pre-License: Baseline/background levels of methane emissions and sources are potentially useful.

Exploration/Development: Baseline/background levels of methane emissions and sources are important to determine how hydraulic fracturing may impact natural leakage rates. Monitoring during exploration is required.

Production: Extensive air monitoring is needed to determine how hydraulic fracturing may impact methane natural leakage rates. Detection of unexpected methane leakage. In-situ monitoring and airshed modelling using complimentary data.

Decommissioning: N/A

Environmental monitoring: Detection of unexpected methane leakage on a regional basis. Complimentary data to in-situ monitoring and airshed modelling.

Geographic coverage and demand

Demand and coverage is global.

Challenges Addressed

OTM:021  Air quality (emissions) monitoring

HC:4106  Air quality monitoring on an airshed and site specific basis

HC:4107  Detection of unexpected methane leakage on a regional basis

PRODUCT SPECIFICATIONS

Input data sources

Satellite data:

  • Operational: GOSAT (2009 – present)
  • Archived: ENVISAT SCIAMACHY and MIPAS (2002 – 2012)
  • Planned: GHGSat, MERLIN IPDA LIDAR, GOSAT-2 TANSO-FTS/2, CarbonSat (ESA), Sentinel-5P (TROPOMI sensor), FY-3D and FY-3F (National Remote Sensing Center of China), Meteor-MP-N1 and N2 (Russian Federal Service for Hydrometorology and Environmental Monitoring).

Additional data:

  • Ground measurements are required for evaluating satellite data and retrieval models; targeted aircraft campaigns can also provide verification and better understanding of source regions. Ground-based measurements from the Total Carbon Column Observing Network (TCCON) supports product development.

Spatial resolution and coverage

The spatial resolution of satellite-based products is relatively coarse and in the range of 0.5‑60 km.

Individual SCIAMACHY pixels are 30 km × 60 km. Some of the models average the data to a regular 1° longitude × 1° latitude grid.

Minimum Mapping Unit (MMU)

N/A

Accuracy / constraints

The SCIAMACHY CH4 data set can be characterized by a single ground pixel retrieval precision of about 1.7%. The airborne MAMAP sensor provides total column relative accuracy of <≈1% on scales of several kilometres for clear sky atmospheric conditions.

Accuracy assessment approach & quality control measures

In all methane emission retrieval programs, ground measurement sites play a critical role in evaluating satellite data and retrieval models; targeted aircraft campaigns can also provide verification and better understanding of source regions.

Frequency / timeliness

Observation frequency: Global monthly mean maps are available from January 2003 to April 2012 (SCIAMACHY) and from June 2009 to September 2012 (GOSAT). Methane flux inversions (MACC project) are available for the period July 2009 to June 2013.

Timeliness of delivery: Following model development and calibration, products are made available immediately, e.g., on a monthly basis.

Availability

Archived SCIAMACHY data are available from ESA. GOSAT data are distributed by JAXA. Methane products are also available from the Tropospheric Emission Monitoring Internet Service (TEMIS).

Delivery / output format

Data type:

  • Raster
  •  Summary statistics

File format:

  • Geotiff or client-specified common spatial formats
  • Standard office formats

 

Download product sheet.


Lead author:

Hatfield Consultants/SRC

Peer reviewer:

OTM/GeoVille, GHSat

Author(s):

Aleksandrowicz, Pierce

Document Title:

emission Monitoring

# of Pages:

4

Circulation:

Internal – Project consortium and science partners

 

External – ESA

                     

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