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Description

GEDI Version 1 data products were decommissioned on February 15, 2022. Users are advised to use the improved GEDI02_A Version 2 data product.

The Global Ecosystem Dynamics Investigation (GEDI) mission aims to characterize ecosystem structure and dynamics to enable radically improved quantification and understanding of the Earth’s carbon cycle and biodiversity. The GEDI instrument produces high resolution laser ranging observations of the 3-dimensional structure of the Earth. GEDI is attached to the International Space Station and collects data globally between 51.6 degrees N and 51.6 degrees S latitudes at the highest resolution and densest sampling of any light detection and ranging (lidar) instrument in orbit to date.

The purpose of the GEDI Level 2A Geolocated Elevation and Height Metrics product (GEDI02_A) is to provide waveform interpretation and extracted products from each GEDI01_B received waveform, including ground elevation, canopy top height, and relative height (RH) metrics. The methodology for generating the GEDI02_A product datasets is adapted from the Land, Vegetation, and Ice Sensor (LVIS) algorithm. The GEDI01_B product is provided in HDF5 format and has a spatial resolution (average footprint) of 25 meters.

The GEDI02_A data product contains 156 variables for each of the eight beams, including ground elevation, canopy top height, relative return energy metrics (describing canopy vertical structure, for example), and many other interpreted products from the return waveforms. Additional information for the variables can be found in the GEDI Level 2A Dictionary.

Known Issues

  • Known Issues: Section 7 of the User Guide provides additional information on known issues.

  • Data acquisition gaps: GEDI data acquisitions were suspended on December 19, 2019 (2019 Day 353) and resumed on January 8, 2020 (2020 Day 8).

Product Summary

Platforms
ISS
Instruments
GEDI
Spatial Extent

N: 90 S: -90 E: 180 W: -180

Spatial Resolution
25 Meters x 25 Meters
Location
GLOBAL LAND
Coordinate System
CARTESIAN
Granule Spatial Representation
NO_SPATIAL
Temporal Extent
2019-04-18 to 2020-09-03
Temporal Resolution
Varies
Data Partner
Land Processes Distributed Active Archive Center (LP DAAC) ,
Global Ecosystem Dynamics Investigation, Goddard Space Flight Center, NASA (NASA/GSFC/GEDI)
Concept ID
C2141085552-LPCLOUD
Data State
DEPRECATED
Number of Files/Granules
0
Processing Level
2A
Published
Updated
Science Keywords
Topography ,
Lidar ,
Plant Phenology ,
VEGETATION HEIGHT ,
Vegetation Cover ,
Canopy Characteristics

File Naming Convention

GEDI02_A_2019247221245_O04131_T05060_02_001_01.h5

The file name begins with the Product Short Name (GEDI02_A), followed by the Julian Date and Time of Acquisition designated as YYYYDDDHHMMSS (2019247221245), the Orbit Number starting with the letter O (O04131), Track Number (T05060), the Positioning and Pointing Determination System type where 00 is predict, 01 rapid, 02 and higher is final (02), the Software Release Number (001), the Granule Production Version (01), and the Data Format (h5).

Documents

Variables

The table below lists the variables contained within a single granule for this dataset. Variables often contain observed or derived geophysical measurements collected from a variety of sources, including remote sensing instruments on satellite and airborne platforms, field campaigns, in situ measurements, and model outputs. The terms variable, parameter, scientific data set, layer, and band have been used across NASA’s Earth science disciplines; however, variable is the designated nomenclature in NASA’s Common Metadata Repository (CMR). Variable metadata attributes such as Name, Description, Units, Data Type, Fill Value, Valid Range, and Scale Factor allow users to efficiently process and analyze the data. The full range of attributes may not be applicable to all variables. Additional information on variable attributes is typically available in the data, user guide, and/or other product documentation.

For questions on a specific variable, please use the Earthdata Forum.

Name Description Units Data Type Fill Value Valid Range Scale Factor Offset
rx_giters Number of iterations to converge Gaussian fit to rxwaveform N/A uint16 N/A 1 to 100 N/A N/A
rx_gloc Location (mean) of the Gaussian fit to the rxwaveform Nanoseconds float32 N/A 0 to 1420 N/A N/A
rx_gloc_error Error on rx_gloc parameter estimate Nanoseconds float32 N/A 0 to 1420 N/A N/A
rx_gwidth Width (1 sigma) of the Gaussian fit to the rxwaveform Nanoseconds float32 N/A 0 to 1420 N/A N/A
rx_gwidth_error Error on rx_gwidth parameter estimate Nanoseconds float32 N/A 0 to 300 N/A N/A
rx_iwaveamps Fraction of integrated waveform at location of each detected mode Number float32 N/A 0 to 1 N/A N/A
rx_maxamp Maximum amplitude of rxwaveform relative to mean noise level Number float32 N/A N/A N/A N/A
rx_maxpeakloc Waveform sample where maximum amplitude of waveform occurs Number uint16 N/A 1 to 1420 N/A N/A
rx_max_mode_count Maximum number of modes saved for each footprint N/A int64 0 0 to 40 N/A N/A
rx_mean_noise_level If amplitude is less than this value, no Gaussian fitting is performed to the rxwaveform Number float64 N/A 0 to 350 N/A N/A
rx_modeamps Amplitudes of each detected mode within waveform Number float32 N/A -100 to 1420 N/A N/A
rx_modeenergytobotloc Total energy from the center of each detected waveform mode to botloc Number float32 N/A -1000 to 1000000 N/A N/A
rx_modelocalenergy Energy between +/- 8 samples of each detected mode, mean noise level removed Number float32 N/A -1000 to 1000000 N/A N/A
rx_modelocalenergyabovemean Energy between +/- 8 samples of each detected mode Number float32 N/A -1000 to 1000000 N/A N/A
rx_modelocalslope Signal trend within +/- 8 samples of each detected mode Number float32 N/A -100 to 100 N/A N/A
rx_modelocs Sample numbers of each detected mode (relative to bin 0 of waveform) Nanoseconds float32 N/A 0 to 1420 N/A N/A
rx_modewidths 1 sigma width estimates of each detected mode in waveform Nanoseconds float32 N/A 0 to 700 N/A N/A
rx_nummodes Number of modes detected in waveform Nanoseconds uint8 N/A N/A N/A N/A
rx_pulsethresh Amplitude used to flag low amplitude return waveforms Number float64 N/A 0 to 4096 N/A N/A
rx_ringthresh Multipler on noise stddev to detect presence of ringing below the mean in the pulse Number float64 N/A 0 to 4096 N/A N/A
rx_searchsize In combination with preprocessor_threshold, used to define area of waveform to be searched by algorithm Nanoseconds float64 0 0 to 500 N/A N/A
rx_sentinel_location Location of sentinel pulse used by sensitivity algorithm Nanoseconds float64 0 0 to 300 N/A N/A
rx_smoothing_width_locs Width of Guassian pulse convolved with waveform to reduce noise prior to toploc/botloc identification Nanoseconds float64 0 0 to 30 N/A N/A
rx_smoothing_width_zcross Width of Guassian pulse convolved with waveform to reduce noise prior to pulse mode identification Nanoseconds float64 0 0 to 30 N/A N/A
rx_smoothwidth Smoothing width to apply to waveforms before Gaussian fitting Nanoseconds float64 N/A 0 to 50 N/A N/A
rx_subbin_resolution Factor of increased vertical resolution relative to native waveform resolution (~0.15 m) N/A int64 0 0 to 10 N/A N/A
rx_use_fixed_thresholds Noise stddev multipliers used to detect the highest and lowest elevation returns N/A int32 0 0 to 1 N/A N/A
sd_corrected Noise standard deviation, corrected for odd/even digitizer bin errors based on pre-launch calibrations Number float32 N/A 0 to 20 N/A N/A
sd_sm Noise standard deviation of the smoothed waveform Number float32 N/A 0 to 100 N/A N/A
search_end Sample number indicating end of signal search Nanoseconds float32 N/A 0 to 1420 N/A N/A
search_start Sample number indicating start of signal search Nanoseconds float32 N/A 0 to 1420 N/A N/A
selected_algorithm Identifier of algorithm selected as identifying the lowest non-noise mode N/A uint8 N/A 1 to 6 N/A N/A
selected_mode Identifier of mode selected as lowest non-noise mode N/A uint8 N/A 0 to 40 N/A N/A
selected_mode_flag Flag indicating status of selected_mode Class Flag uint8 N/A 0 to 4 N/A N/A
sensitivity Maxmimum canopy cover that can be penetrated N/A float32 N/A 0 to 1 N/A N/A
sensitivity_aN Maxmimum canopy cover, using algorithm N, that can be penetrated considering the SNR of the waveform. This Variable record represents sensitivity_a1 through sensitivity_a6. N/A float32 N/A 0 to 1 N/A N/A
shot_number Shot number N/A uint64 N/A N/A N/A N/A
smoothing_width_locs Used in debugging only Nanoseconds float64 N/A 0 to 1420 N/A N/A
smoothwidth Width of Gaussian function used to smooth noise sections of waveforms Nanoseconds float32 N/A 0 to 20 N/A N/A
smoothwidth_zcross Width of Gaussian function used to smooth waveform between botloc and toploc Nanoseconds float32 N/A 0 to 20 N/A N/A
solar_azimuth Solar azimuth N/A float32 N/A N/A N/A N/A
solar_elevation Solar elevation N/A float32 N/A N/A N/A N/A
stale_return_flag Flag indicating return signal above detection threshold was not detected Class Flag uint8 N/A 0 to 1 N/A N/A
stddev Noise standdard deviation used in algorithm Number float32 N/A 0 to 4096 N/A N/A
surface_flag Indicates elev_lowestmode is within 300 m of DEM or MSS Class Flag uint8 N/A 0 to 1 N/A N/A
toploc Sample number of highest detected return Number float32 N/A 0 to 1420 N/A N/A
toploc_miss Flag indicating algorithm didn't detect valid toploc value Class Flag uint8 N/A 0 to 1 N/A N/A
zcross Sample number of center of lowest mode above noise level Nanoseconds float32 N/A 0 to 1420 N/A N/A
zcross0 Location of center of highest mode above noise level relative to bin0 of waveform Nanoseconds float32 N/A 0 to 1420 N/A N/A
zcross_amp Amplitude of smoothed waveform at lowest detected mode Number float32 N/A 0 to 4096 N/A N/A
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