NASA Global Ecosystem Dynamics Investigation (GEDI)
Update and Potential Collaboration
GEDI Science Definition Team
1st CCI Biomass User Workshop – September 25-26, 2018 – Paris
Presentation Outline
• Science Goals, Questions and Objectives• Current Mission Status• L1 Science Requirements• Science Approach and Data Products• Biomass Cal/Val Activities• Summary
1st CCI Biomass User Workshop – September 25-26, 2018 – Paris
Global Ecosystem Dynamics Investigation
High Resolution Laser Ranging of the Earth’s Forests and
Topography
1st CCI Biomass User Workshop – September 25-26, 2018 – Paris
Science Questions and Objectives
Carbon Cycle Biodiversity
GEDI Goal: Advance our ability to characterize the effects of changing climate and land use on ecosystem
structure and dynamics
1st CCI Biomass User Workshop – September 25-26, 2018 – Paris
Current Mission Status
• Currently in Phase D• TVAC completed Sunday• Oct TBD – KDP-D/E• Oct 13th – Ship Date• Nov 27th – LRD
1st CCI Biomass User Workshop – September 25-26, 2018 – Paris
GEDI Lidar Measurements
GEDI’s sole observable is the lidar waveform which provides ground
elevation, canopy height, cover and various profiles and metrics.
GEDI makes up to 10 billion observations of forest and
land surface structure over its nominal two-year mission
Amplitude
RH
75
RH
50
RH25
Normalized Cumulative Return Energy
110
120
130
140
150
1600.25 0.5 0.75 1.00
0 50 100 150 200
WGS
84 e
leva
tion
(m)
Elevation of center of lowest mode
Highest reflecting surfaceelevation
Lowest reflecting surfaceelevation
25 m
1st CCI Biomass User Workshop – September 25-26, 2018 – Paris
• Acquire lidar canopy vertical profile data required to estimate aboveground woody carbon density for the Earth’s global tropical and temperate forests within the ISS orbital coverage at ≤ 1 km resolution. At the end of two years after on-orbit checkout, at least 80% of the 1 km cells will meet an accuracy within 20% standard error, or 20 Mg/ha whichever is greater, subject to instrument availability.
• Acquire transects (that is, near contiguous, along-track laser footprint observations) of tropical & temperate forest canopy vertical profiles from the top of canopy to the ground. Instrument performance must be sufficient to acquire profiles in conditions of up to about 95% canopy cover for all beams. Additionally, at least one laser beam must have sufficient power to acquire profiles in conditions of up to 98% canopy cover.
• Record, validate, publish, and deliver science data records (L0-L1B) and validated data products and model outputs (L2-L4) to the DAACs designated by NASA for use by the scientific community.
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Baseline Requirements
80% of 1 km cells meet a biomass accuracy of 20% SE or 20 Mg/ha
Acquire transects of canopy profiles in conditions of up to 95%/98% cover
1st CCI Biomass User Workshop – September 25-26, 2018 – Paris
• Previously: 1 power and 2 coverage lasers ® 3 lasers, 5 beams, 10 tracks• Now: 2 power and 1 coverage laser ® 3 lasers, 4 beams, 8 tracks
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Science Changes – New Mission Configuration
5.4 km
There is no impact to Level 1 Science Requirements
1st CCI Biomass User Workshop – September 25-26, 2018 – Paris
• GEDI measurement is the waveform (Level 1B)- Waveform is used to derive height and profile metrics using established algorithms (Level
2 & Level 3)
• GEDI produces biomass (Level 4) empirically at footprint and gridded level - Other L4 products produced only for selected areas as demonstrations
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Science Approach and Data Products
1st CCI Biomass User Workshop – September 25-26, 2018 – Paris
GEDI Science Data Products
Product/ Data File Description Source
First Data Delivery After
IOC
DataLatency
ArchiveSite
GEDI00_B Level 0B Instrument Products (Sci, GPS, ST) MOC Within 24 hours of receipt
at GSFC Within 24 hours of receipt at GSFC LPDAAC
GEDI01_A Level 1A Waveform Fitted Parameters SOC First 2 months of L1
released at 6 months4 months in monthly intervals LPDAAC
GEDI01_B Level 1B Geolocated Waveforms SOC First 2 months of L1
released at 6 months4 months in monthly intervals LPDAAC
GEDI02_ALevel 2A Footprint Elevation and Height Metrics
SOC First 2 months of L2 released at 6 months
4 months in monthly intervals LPDAAC
GEDI02_B Level 2B Footprint Cover and Profile Metrics SOC First 2 months of L2
released at 6 months4 months in monthly intervals LPDAAC
GEDI03 Level 3A Gridded Land Surface Metrics SOC
Populated with first 2 months of L2 data at 6 months
4 months in monthly intervals ORNLDAAC
GEDI04_A Level 4A Footprint Aboveground Biomass SOC First 12 months of L3 data
at 17 months
6 months after global sampling required to meet L1 requirement
ORNLDAAC
GEDI04_B Level 4B Gridded Aboveground Biomass SOC First 12 months of L3 data
at 17 months
6 months after global sampling required to meet L1 requirement
ORNLDAAC
1st CCI Biomass User Workshop – September 25-26, 2018 – Paris
• GEDI relies on crowd-sourced field and airborne lidar data• Pre-launch calibration allows us to exploit a vast array of past and present
field studies
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Pre-Launch Calibration for Biomass
GEDI Forest StructureData Base
GEDI PerformanceTool
1st CCI Biomass User Workshop – September 25-26, 2018 – Paris
• GEDI relies on crowd-sourced field and airborne lidar data• Pre-launch calibration allows us to exploit a vast array of past and present
field studies
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Pre-Launch Calibration for Biomass
GEDI Forest StructureData Base
GEDI PerformanceTool
CoverageStrong
1st CCI Biomass User Workshop – September 25-26, 2018 – Paris
• Complex effort spanning many different organizations • Common framework required to standardize existing field and airborne lidar
data• Every plot has associated small footprint lidar data as well as field data
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GEDI Forest Structure Database (July 2018)
Number of plots Number of simulated GEDI footprints (0.0625 ha)
1,448,033 trees in 4,823 plots (native resolution) from 95 projects
1st CCI Biomass User Workshop – September 25-26, 2018 – Paris
• Candidate models selected - ATBD designed with flexibility to easily modify/change models
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GEDI Footprint Biomass Models
Footprint-level biomass models are built from existing coincident ALS/field data
Systematic comparison of model performance based on cross-validation and geographic transferability
Stratification of modelsPlant Functional Type (PFT)Continental Region
OLS Regression
RMSE = 55.8%Stratified by PFT and Region
1st CCI Biomass User Workshop – September 25-26, 2018 – Paris
• CEOS Land Product Validation Biomass Focus Area- GEDI team co-leading validation protocol development- >50 international biomass experts writing document for well vetted product
validation- GEDI team will follow CEOS protocol for post-launch biomass product validation
• Multi-Mission Analysis Platform- NASA/ESA activity for increased data sharing, open code and algorithm
development on upcoming missions (NISAR, BIOMASS, GEDI)- NASA MAP will ingest GEDI field and lidar data to bolster consistent cal/val
activities
• Multi-Mission Biomass Cal/Val Subgroup- Members of GEDI, ICESat-2, NISAR and ESA’s BIOMASS have monthly meetings to
discuss cal/val- Ensure consistent cal/val approaches (following CEOS)- Coordinate new field and airborne collections
GEDI Cal/Val Partnerships and Collaboration
1st CCI Biomass User Workshop – September 25-26, 2018 – Paris
• GEDI is scheduled for launch on November 27, 2018• Data products are clearly defined and based on mature algorithms
- GEDI L4 biomass gridding (Sean Healey) is next!
• Pre- and post-launch calibration and validation approaches are in place and final details being formalized
• GEDI continues to leverage activities across other NASA missions and programs, as well as international activities to both provide additional cal/val margins and to extend data products
• The GEDI team are working closely with CEOS groups, the NASA-ESA Multi-Mission Analysis Platform, and other missions teams on data sharing and coordinated cal/val- Laura Duncanson, 8:45AM Wednesday- New opportunities with CCI+ Biomass
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Summary
1st CCI Biomass User Workshop – September 25-26, 2018 – Paris