Methane Products Overview¶
Each TanagerMethane item will have the plumes that are able to be detected by a human operator within a corresponding TanagerScene based on a methane enhancement data layer, derived from a matched filter (doi:10.5194/amt-8-4383-2015).
TanagerMethane products are only offered in their orthorectified format. These products can be obtained from the Planet APIs through the TanagerScene item type.
A Tanager Methane Product is representative of a single plume and will have the dimensions of the plume extent. They are represented in the Planet Platform as the TanagerMethane item type.
The Methane QuickLook (MQL) bundle is designed for easy interpretation by methane experts with limited remote sensing knowledge. Within each bundle customers will have access to multiple imagery assets, listed below, for their purposes.
Tanager Methane QuickLook Products¶
Tanager’s Methane QuickLook is a low latency, derived methane product that will reveal point source emission locations and estimates of magnitude in kg/hr for observed plumes This product will be delivered to customers within a 72 hour timeframe after acquisition enabling customers to quickly identify and take action where emissions are detected.
Available Assets¶
| Asset Name | Asset-Type | Description |
|---|---|---|
| Ortho Methane QuickLook Plume | ortho_ql_ch4 | Preliminary 8-bit scaled methane plume intensity in (ppm-m) parts-per-million-meter, in GeoTIFF format. The image will contain an alpha channel indicating pixels with no plume detections. |
| MethaneQuickLook Plume Metadata | ql_ch4_json | Preliminary plume locations, length, size in kg/hr and confidence measure indicating the level of visual interpretation certainty, in GeoJSON format. |
Methane Plume Metadata¶
Relevant for ql_ch4_json TanagerMethane assets.
| Parameter | Description | Type |
|---|---|---|
| plume_id | Unique identifier for each plume. The format is <stripid>_<part>. The “part” postfix (e.g., "A", “B”, “C”) identifies multiple plumes captured in the same image in the order they were detected. |
string |
| plume_latitude | Latitude estimate of plume origin. | |
| plume_longitude | Longitude estimate of plume origin. | |
| plume_quality | This field is only used for Methane QuickLook, ql_ch4_json asset-type. Qualitative assessment of plume quality captured by a human operator during the plume detection process (good, questionable or bad). More on Plume quality classification below. | string |
| datetime | Date and time of the acquisition in Coordinated Universal Time (UTC). | datetime |
| ime | The total kilograms (kg) of methane in a plume above the background concentration at the time of image capture. | float |
| fetch | Plume length, meters (m) | float |
| emission | Quantified emission rate of a plume, estimated using the Integrated Methane Enhancement method. (Duren et al., 2019 - "California's Methane Super-Emitters", Nature) | |
| emission_uncertainty | The uncertainty in an emission rate, derived from uncertainty in IME and wind speed. | |
| wind_speed_avg | Mean wind speed m/s | float |
| wind_speed_std | Standard deviation wind speed m/s | float |
| wind_direction_avg | Wind direction (degrees) | float |
| wind_direction_std | Wind direction standard deviation (degrees) | float |
| wind_source | Wind source from reanalysis. (e.g. Openmeteo, HRRR, ERA5) | string |
| strip_id | Strip ID of the Tanager collect that was used for plume detection. | string |
Item Properties¶
The following is the metadata that is publicly available in the Data API for each TanagerScene and TanagerMethane item.
| Parameter | Description | Type |
|---|---|---|
| _permissions | Assets available for the item which the authenticated user has permission to download. | array |
| geometry | Geographic boundary of the item’s footprint, formatted as a GeoJSON polygon. | json |
| id | Globally unique item identifier. | string |
| acquired | The RFC 3339 acquisition time of the image. | datetime |
| cloud_percent | Percent of cloud values in the dataset. Cloud values represent scene content areas (non-blackfilled) that contain opaque clouds which prevent reliable interpretation of the land cover content. | double |
| collection_mode | Maximum Sensitivity (4x8), Standard Sensitivity (1x8), Glint | string |
| ground_control | If the image meets the positional accuracy specifications this value will be true. If the image has uncertain positional accuracy, this value will be false. | boolean |
| gsd | The average ground sampling distance of the associated Item. Computed for each item to account for variations over the length of a collection. | double |
| item_type | The name of the item type. For example, TanagerScene or TanagerMethane. | string (e.g. TanagerScene) |
| light_haze_percent | Percent of light haze values in the dataset. Light haze values represent scene content areas (non-blackfilled) that contain thin low altitude clouds, higher altitude cirrus clouds, soot and dust which allow reliable recognition of land cover features, and have up to +/-10% uncertainty on commonly used indices (EVI and NDWI). | double |
| pixel_resolution | Pixel resolution of the ortho products associated with this Item. | double |
| provider | Name of the imagery provider. | string (e.g. "tanager","planetscope", "skysat") |
| published | The RFC 3339 timestamp at which this item was added to the API. | datetime |
| publishing_stage | Stage of publishing for an item. TanagerScene items will be first published and remain in the “finalized” stage. | string |
| quality_category | Metric for image quality. To qualify for “standard” image quality an image must meet a variety of quality standards. If the image does not meet these criteria it is considered “test” quality. | string: “standard” or “test” |
| satellite_azimuth | Tanager’s off track pointing direction, in degrees (0-360). | double |
| satellite_id | Globally unique identifier of the satellite that acquired the underlying imagery. I.E. 4001 | string |
| strip_id | The unique identifier of the image strip that the item came from. | string |
| sun_azimuth | The angle of the sun, as seen by the observer, measured clockwise from the north (0 - 360). | double |
| sun_elevation | The angle of the sun above the horizon (0 - 90). | double |
| updated | The RFC 3339 timestamp at which this item was updated in the API. | datetime |
| view_angle | The satellite’s across-track, off-nadir viewing angle. | double |
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