Difference between revisions of "Standard Names For Satellite Observations"
From Earth Science Information Partners (ESIP)
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The [http://cf-pcmdi.llnl.gov/ Climate and Forecast (CF) metadata convention] maintains a list of [http://cf-pcmdi.llnl.gov/documents/cf-standard-names/ ''standard names''] for data stored in variables of a netCDF file. Not many standard names in that list are relevant to satellite observation data so additional names are proposed here. The new names and accompanying information will follow the CF [http://cf-pcmdi.llnl.gov/documents/cf-standard-names/guidelines guidelines]. | The [http://cf-pcmdi.llnl.gov/ Climate and Forecast (CF) metadata convention] maintains a list of [http://cf-pcmdi.llnl.gov/documents/cf-standard-names/ ''standard names''] for data stored in variables of a netCDF file. Not many standard names in that list are relevant to satellite observation data so additional names are proposed here. The new names and accompanying information will follow the CF [http://cf-pcmdi.llnl.gov/documents/cf-standard-names/guidelines guidelines]. | ||
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==Proposed Names== | ==Proposed Names== | ||
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|'''Definition''' | |'''Definition''' | ||
|Alphanumeric identifier of a sensor band. | |Alphanumeric identifier of a sensor band. | ||
| + | |} | ||
| + | |||
| + | {| class="wikitable" | ||
| + | |'''Standard name''' | ||
| + | | central_wavelength | ||
| + | |- | ||
| + | |'''Canonical units''' | ||
| + | | m | ||
| + | |- | ||
| + | |'''Definition''' | ||
| + | | The central wavelength of a sensor's band, calculated as the first moment of the band's spectral response function. | ||
| + | |} | ||
| + | |||
| + | |||
| + | {| class="wikitable" | ||
| + | |'''Standard name''' | ||
| + | | central_wavenumber | ||
| + | |- | ||
| + | |'''Canonical units''' | ||
| + | | m-1 | ||
| + | |- | ||
| + | |'''Definition''' | ||
| + | | The central wavenumber of a sensor's band, calculated as the first moment of the band's spectral response function. | ||
| + | |} | ||
| + | |||
| + | {| class="wikitable" | ||
| + | |'''Standard name''' | ||
| + | | central_frequency | ||
| + | |- | ||
| + | |'''Canonical units''' | ||
| + | | Hz | ||
| + | |- | ||
| + | |'''Definition''' | ||
| + | | The central frequency of a sensor's band, calculated as the first moment of the band's spectral response function. | ||
|} | |} | ||
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|'''Definition''' | |'''Definition''' | ||
|The difference between top-of-atmosphere (TOA) brightness temperature of the reference sensor and TOA brightness temperature of the monitored sensor. This TOA brightness temperature difference is a measure of the calibration difference between the monitored and reference sensors. Standard scene is a target area with typical Earth surface and atmospheric conditions that is accepted as a reference. Brightness temperature of a body is the temperature of a black body which radiates the same power per unit solid angle per unit area at a given wavenumber. TOA brightness temperature of the standard scene is calculated using a radiative transfer simulation for a given viewing geometry. The resultant top-of-atmosphere spectral radiance is then integrated with each sensor's spectral response function and converted to equivalent brightness temperature. | |The difference between top-of-atmosphere (TOA) brightness temperature of the reference sensor and TOA brightness temperature of the monitored sensor. This TOA brightness temperature difference is a measure of the calibration difference between the monitored and reference sensors. Standard scene is a target area with typical Earth surface and atmospheric conditions that is accepted as a reference. Brightness temperature of a body is the temperature of a black body which radiates the same power per unit solid angle per unit area at a given wavenumber. TOA brightness temperature of the standard scene is calculated using a radiative transfer simulation for a given viewing geometry. The resultant top-of-atmosphere spectral radiance is then integrated with each sensor's spectral response function and converted to equivalent brightness temperature. | ||
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Revision as of 21:29, August 27, 2012
The Climate and Forecast (CF) metadata convention maintains a list of standard names for data stored in variables of a netCDF file. Not many standard names in that list are relevant to satellite observation data so additional names are proposed here. The new names and accompanying information will follow the CF guidelines.
Proposed Names
| Standard name | sensor_band_identifier |
| Canonical units | N/A |
| Definition | Alphanumeric identifier of a sensor band. |
| Standard name | central_wavelength |
| Canonical units | m |
| Definition | The central wavelength of a sensor's band, calculated as the first moment of the band's spectral response function. |
| Standard name | central_wavenumber |
| Canonical units | m-1 |
| Definition | The central wavenumber of a sensor's band, calculated as the first moment of the band's spectral response function. |
| Standard name | central_frequency |
| Canonical units | Hz |
| Definition | The central frequency of a sensor's band, calculated as the first moment of the band's spectral response function. |
| Standard name | time_interval |
| Canonical units | s |
| Definition | An interval of time. |
| Standard name | datetime_iso8601 |
| Canonical units | N/A |
| Definition | String containing date-time information in one of the ISO 8601 formats. Variables with this standard name cannot serve as coordinate variables. |
| Standard name | platform_zenith_angle |
| Canonical units | degree |
| Definition | The angle between the line of sight to the platform and the local zenith. |
| Standard name | sensor_zenith_angle |
| Canonical units | degree |
| Definition | The angle between the line of sight to the sensor and the local zenith. |
| Standard name | platform_scan_angle |
| Canonical units | degree |
| Definition | The angle between the line of sight from the platform and the nadir line. Nadir is the direction given by the vertical from the platform looking towards the center of the Earth. |
| Standard name | sensor_scan_angle |
| Canonical units | degree |
| Definition | The angle between the line of sight from the sensor and the nadir line. Nadir is the direction given by the vertical from the sensor looking towards the center of the Earth. |
| Standard name | platform_azimuth_angle |
| Canonical units | degree |
| Definition | The horizontal angle between the line of sight to the platform and a reference direction which is often due north. The angle is measured clockwise. |
| Standard name | sensor_azimuth_angle |
| Canonical units | degree |
| Definition | The horizontal angle between the line of sight to the sensor and a reference direction which is often due north. The angle is measured clockwise. |
| Standard name | relative_sensor_azimuth_angle |
| Canonical units | degree |
| Definition | Difference between two sensor_azimuth_angle values. |
| Standard name | toa_outgoing_spectral_radiance |
| Canonical units | mW m-2 sr-1 (cm-1)-1 |
| Definition | "toa" means top of atmosphere; "outgoing" means emitted toward outer space; "spectral" means per unit wavenumber or as a function of wavenumber. Radiance is the radiant power per unit area in a particular direction per unit of solid angle. |
| Standard name | toa_outgoing_spectral_radiance_mean_within_collocation_target |
| Canonical units | mW m-2 sr-1 (cm-1)-1 |
| Definition | An average of toa_outgoing_spectral_radiance observations from sensor's adjacent field of views within a collocation target. Collocation target is an area on the Earth's surface at which observations from at least two sensors are collected. Its size is defined by the sensor with the largest field of view footprint. |
| Standard name | toa_outgoing_spectral_radiance_stdev_within_collocation_target |
| Canonical units | mW m-2 sr-1 (cm-1)-1 |
| Definition | Standard deviation of toa_outgoing_spectral_radiance observations from sensor's adjacent field of views within a collocation target. Collocation target is an area on the Earth's surface at which observations from at least two sensors are collected. Its size is defined by the sensor with the largest field of view footprint. |
| Standard name | toa_outgoing_spectral_radiance_mean_within_collocation_scene |
| Canonical units | mW m-2 sr-1 (cm-1)-1 |
| Definition | An average of toa_outgoing_spectral_radiance observations within a collocation scene. Collocation scene is a grouping of sensor's adjacent field of views (FOVs) centered on a collocation target. Collocation target is an area on the Earth's surface at which observations from at least two sensors are collected. Its size is defined by the sensor with the largest FOV footprint. Collocation scene's size is typically about twice the size of its collocation target. |
| Standard name | toa_outgoing_spectral_radiance_stdev_within_collocation_scene |
| Canonical units | mW m-2 sr-1 (cm-1)-1 |
| Definition | Standard deviation of toa_outgoing_spectral_radiance observations within a collocation scene. Collocation scene is a grouping of sensor's adjacent field of views (FOVs) centered on a collocation target. Collocation target is an area on the Earth's surface at which observations from at least two sensors are collected. Its size is defined by the sensor with the largest FOV footprint. Collocation scene's size is typically about twice the size of its collocation target. |
| Standard name | linear_term_of_spectral_radiance_correction_due_to_intercalibration |
| Canonical units | 1 |
| Definition | Linear term (slope) of the formula for correcting measured spectral radiance. The correction is derived from intercalibration between the monitored and the reference sensor. The resulting corrected spectral radiance of the monitored sensor becomes comparable to measured spectral radiance of the reference sensor. "Spectral" means per unit wavenumber or as a function of wavenumber. Radiance is the radiant power per unit area in a particular direction per unit of solid angle. |
| Standard name | constant_term_of_spectral_radiance_correction_due_to_intercalibration |
| Canonical units | mW m-2 sr-1 (cm-1)-1 |
| Definition | Constant term (offset) of the formula for correcting measured spectral radiance. The correction is derived from intercalibration between the monitored and the reference sensor. The resulting corrected spectral radiance of the monitored sensor becomes comparable with measured spectral radiance of the reference sensor. "Spectral" means per unit wavenumber or as a function of wavenumber. Radiance is the radiant power per unit area in a particular direction per unit of solid angle. |
| Standard name | covariance_between_constant_and_linear_terms_of_spectral_radiance_correction |
| Canonical units | mW m-2 sr-1 (cm-1)-1 |
| Definition | Covariance between constant_term_of_spectral_radiance_correction_due_to_intercalibration and linear_term_of_spectral_radiance_correction_due_to_intercalibration values. |
| Standard name | toa_brightness_temperature_of_standard_scene |
| Canonical units | K |
| Definition | "toa" means top of atmosphere. Brightness temperature of a body is the temperature of a black body which radiates the same power per unit solid angle per unit area at a given wavenumber. Standard scene is a target area with typical Earth surface and atmospheric conditions that is accepted as a reference. The top-of-atmosphere radiance of the standard scene is calculated using a radiative transfer model for a given viewing geometry. The resultant top-of-atmosphere spectral radiance is then integrated with a sensor's spectral response function and converted to equivalent brightness temperature. |
| Standard name | toa_brightness_temperature_bias_at_standard_scene_wrt_intercalibration |
| Canonical units | K |
| Definition | The difference between top-of-atmosphere (TOA) brightness temperature of the reference sensor and TOA brightness temperature of the monitored sensor. This TOA brightness temperature difference is a measure of the calibration difference between the monitored and reference sensors. Standard scene is a target area with typical Earth surface and atmospheric conditions that is accepted as a reference. Brightness temperature of a body is the temperature of a black body which radiates the same power per unit solid angle per unit area at a given wavenumber. TOA brightness temperature of the standard scene is calculated using a radiative transfer simulation for a given viewing geometry. The resultant top-of-atmosphere spectral radiance is then integrated with each sensor's spectral response function and converted to equivalent brightness temperature. |
Table Template for Standard Name Proposals
| Standard name | ...standard name...
|
| Canonical units | ...units...
|
| Definition | ...text...
|
