Skip to main content
ORNL DAAC HomeNASA Home
DAAC Home > Get Data > NASA Projects > Arctic-Boreal Vulnerability Experiment (ABoVE) > User guide

ABoVE: Reflectance Spectra of Tundra Plant Communities across Northern Alaska

Get Data

Documentation Revision Date: 2019-07-19

Dataset Version: 1

Summary

This dataset reports full-spectrum (350-2500 nm) reflectance measurements of diverse plant communities at the plot-level and individual plant species at the leaf-level, at multiple sites across northern Alaska during the 2017 and 2018 summer field seasons. Plot-level reflectance data (1 m2) include an assemblage of vascular and non-vascular species comprising tundra plant communities, while leaf-level scans are specific to one particular tundra species. Reflectance measurements were collected using a HR-1024i spectrometer and data were calibrated using a Spectralon white reference panel during sampling to correct for changing light conditions. Sampling methods and data and metadata structure follow that of the Ecological Spectral Information System (EcoSIS) Spectral Library.

This dataset contain raw reflectance spectra for various tundra vegetation plots and species leaves and has not been analyzed or processed to quantify uncertainty. Measurements are being collected during the 2019 growing season and will be added to this dataset.

There are four data files provided with this dataset, two for each year, including a spectral library file with full-spectrum (350-2500 nm) reflectance observations and a metadata file with corresponding sample characteristics. Companion files include readme *.txt files for most measurement sites with general site descriptions and measurement plot details and photo collections (*.jpg) of most measured plots, plants, and leaf samples.

Figure 1. In situ measurement plot at a Common Garden Ecotype site near Eagle Creek, Alaska. Common garden sites (6 total) were established with different populations of the tussock-forming sedge, E. vaginatum, taken from different latitudes in Alaska. Source: EagleCreek_Ecot_170728_Images/DSCN5451.JPG

Citation

Zesati, S.V., C.E. Tweedie, K.F. Huemmrich, P.K. Campbell, and M. Velez-Reyes. 2019. ABoVE: Reflectance Spectra of Tundra Plant Communities across Northern Alaska. ORNL DAAC, Oak Ridge, Tennessee, USA. https://doi.org/10.3334/ORNLDAAC/1685

Table of Contents

  1. Dataset Overview
  2. Data Characteristics
  3. Application and Derivation
  4. Quality Assessment
  5. Data Acquisition, Materials, and Methods
  6. Data Access
  7. References

Dataset Overview

This dataset reports full-spectrum (350-2500 nm) reflectance measurements of diverse plant communities at the plot-level and individual plant species at the leaf-level, at multiple sites across northern Alaska during the 2017 and 2018 summer field seasons. Plot-level reflectance data (1 m2) include an assemblage of vascular and non-vascular species comprising tundra plant communities, while leaf-level scans are specific to one particular tundra species. Reflectance measurements were collected using a HR-1024i spectrometer and data were calibrated using a Spectralon white reference panel during sampling to correct for changing light conditions. Sampling methods and data and metadata structure follow that of the Ecological Spectral Information System (EcoSIS) Spectral Library. This dataset contain raw reflectance spectra for various tundra vegetation plots and species leaves and has not been analyzed or processed to quantify uncertainty.

Project: Arctic-Boreal Vulnerability Experiment

The Arctic-Boreal Vulnerability Experiment (ABoVE) is a NASA Terrestrial Ecology Program field campaign based in Alaska and western Canada between 2016 and 2021. Research for ABoVE links field-based, process-level studies with geospatial data products derived from airborne and satellite sensors, providing a foundation for improving the analysis and modeling capabilities needed to understand and predict ecosystem responses and societal implications.

Acknowledgements:

NASA ABoVE Grant NNX17AC58A and Research Opportunities in Space and Earth Sciences Program, Grant NNX13AK85A.

Data Characteristics

There are four data files provided with this dataset, two for each year, including a spectral library file with full-spectrum (350-2500 nm) reflectance observations and a metadata file with corresponding sample characteristics. Companion files include readme *.txt files for most measurement sites with general site descriptions and measurement plot details and photo collections (*.jpg) of most measured plots, plants, and leaf samples. 

Spatial Coverage:  Northern Alaska

ABoVE Reference Locations:

Domain: Core ABoVE

ABoVE Grid cells: Ch051v019, Ch049v007, Ch050v007, Ch046v008, Ch048v020, Ch048v021, Ch044v023, Ch044v033

Spatial resolution: Multiple points

Temporal coverage: 2017-07-18 to 2018-08-14

Temporal resolution: one or more measurements during a growing season at each plot

Study Areas (All latitude and longitude given in decimal degrees)

Site Westernmost Longitude Easternmost Longitude Northernmost Latitude Southernmost Latitude
Northern Alaska -157.412046 -145.51512 71.34615 65.43485

 

Data File Information

There are four data files provided with this dataset, two for each year, including a spectral library file with full-spectrum (350-2500 nm) reflectance observations and a metadata file with corresponding sample characteristics. Companion files include readme *.txt files for most measurement sites with general site descriptions and measurement plot details and photo collections (*.jpg) of most measured plots, plants, and leaf samples. 

Table 1. Data and companion file names and descriptions..

File names Description Notes
sel_2017_spectral_library_svc_data.csv Full-spectrum (350-2500 nm) reflectance measurements of plant communities, plants, and leaves collected in 2017. Data file structure and content follow that of Ecological Spectral Information System (EcoSIS) Spectral Library. (https://ecosis.org/)
sel_2018_spectral_library_svc_data.csv Same as above, but data collected in 2018.  
sel_2017_spectral_library_svc_metadata.csv   Metadata file with corresponding sample characteristics for 2017 measurements. Unique row identifier aligns “row for row” with measurement file. Metadata file structure and content follow that of Ecological Spectral Information System (EcoSIS) Spectral Library. (https://ecosis.org/)
sel_2018_spectral_library_svc_metadata.csv Same as above, but data collected in 2018.  
     Companion Files    
Site and Measurement Readme Files (readme_*.txt)  28 Readme files General site descriptions and measurement plot details.  See Table 2 for location and site crosswalk to Readme files.
Image Files (*.zip)  24 compressed files Collections of images of plots, plants, and leaf samples.  Note that individual image files (*.jpg) are not always named by plot. Nevertheless, the order of the plot images in a collection, matches the order of the plot measurements in the data/metadata files. See Table 2 for location and site crosswalk to image files.

 

Table 2. 2017 and 2018 locations and measurement sites paired with respective Readme files and Collections of site, plant, and leaf images.

location 2017 site_name Site and Measurement (readme_*.txt) Image Files (*.zip) Count 2017 2018 site_name Count 2018
Atqasuk CALM- Circumpolar Active Layer Monitoring Atqasuk_CALM_Spectral_Data_Metadata Atqasuk_CALM_All_Dates_Images 30 same 64
Atqasuk LEAF - Plant Leaf Spectra Atqasuk_LEAF_Spectral_Data Atqasuk_Leaf_170805_Images 95    
Atqasuk MISP- Mobile Instrumented Sensor Platform Atqasuk_MISP_Spectral_Data Atqasuk_MISP_All_Dates_Images 100 same 50
Atqasuk         PLANT - Plant Spectra: Opportunistic Samples 20
Barrow (Utqiagvik) BEO- Barrow Environmental Observatory Biocomplexity Utqiagvik_BEO_Spectral_Data_Metadata Utqiagvik_BEO_170809_Images 59    
Barrow BMBV - Barrow Mounds Bowerville Utqiagvik_Mounds_Site_Spectral_Data_ Metadata Utqiagvik_BMBV_170816_Images 49    
Barrow BMDC - Barrow Mounds Duck Camp Utqiagvik_Mounds_Site_Spectral_Data_ Metadata Utqiagvik_BMDC_170816_Images 53    
Barrow CALM- Circumpolar Active Layer Monitoring Utqiagvik_CALM_Spectral_Data_Metadata Utqiagvik_CALM_All_Dates_Images 30 same 115
Barrow COAST - Chukchi Coast Spectroscopy  Utqiagvik_Chukchi_Coast_Spectral_Data_ Metadata Utqiagvik_Chukchi_Coast_170818_ Images 33 same 38
Barrow COAST - Elson Coast Spectroscopy    Utqiagvik_Elson_Coast_170819_Images 76    
Barrow DEM- Digital Elevation Model Site Utqiagvik_DEM_Site_Spectral_Data_Metadata Utqiagvik_DEM_170814_Images 28    
Barrow ITEX - International Tundra Experiment (Dry) Utqiagvik_ITEX_Spectral_Data_Metadata   31    
Barrow         ITEX - (Dry):  Site 1 subdivision 24
Barrow         ITEX - (Dry): Site 3 subdivision 180
Barrow ITEX - International Tundra Experiment (Wet) Utqiagvik_ITEX_Spectral_Data_Metadata   48 same 156
Barrow LEAF - Plant Leaf Spectra Utqiagvik_LEAF_Spectral_Data_Metadata Utqiagvik_Leaf_170807_Images 85    
Barrow MetTower - D Utqiagvik_MetStationD_Spectral_Data_ Metadata Utqiagvik_Met_Tower_170813_Images 25    
Barrow MICRO - Microtopo Grid (Row A) Utqiagvik_Microtopo_Historical_Site_Spectral_ Data_Metadata   68    
Barrow MICRO - Microtopo Grid (Row B) Utqiagvik_Microtopo_Historical_Site_Spectral_ Data_Metadata   68    
Barrow MISP- Mobile Instrumented Sensor Platform Utqiagvik_MISP_Spectral_Data_Metadata Utqiagvik_MISP_All_Dates_Images 90 same 250
Barrow MISP- Mobile Instrumented Sensor Platform (Diurnal Run) Utqiagvik_MISP_Spectral_Data_Metadata   546    
Barrow OSLEAF - Oil Spill Plant Leaf Spectra Utqiagvik_OSLEAF_Spectral_Data_Metadata Utqiagvik_OSLEAF_170815_Images 118    
Barrow OSR - Oil Spill Runway Utqiagvik_OSRW_Spectral_Data_Metadata Utqiagvik_OSRW_170814_Images 7    
Barrow PLANT - Plant Spectra Utqiagvik_Pfrigidus_Spectral_Data_Metadata Utqiagvik_PetFri_170810_Images 17    
Barrow         Drain Ponds Site: Opportunistic Samples 61
Barrow         Pond Margins Site: Opportunistic Samples 44
Coldfoot Ecotype Coldfoot_Ecotype_Spectral_Data_Metadata Coldfoot_Ecot_170727_Images 85    
Eagle Creek Ecotype EagleCreek_Ecotype_Spectral_Data_Metadata EagleCreek_Ecot_170728_Images 18    
Eagle Creek LEAF - Plant Leaf Spectra EagleCreek_LEAF_Spectral_Data_Metadata (*) EagleCreek_Leaf_170729_Images 90    
Imnavit MISP- Mobile Instrumented Sensor Platform Imnavait_MISP_Spectral_Data_Metadata   46    
Imnavait         CALM- Circumpolar Active Layer Monitoring 64
No Name Creek LEAF - Plant Leaf Spectra NoNameCreek_LEAF_Spectral_Data_Metadata (*) NoName_Creek_Leaf_170731_Images 26    
Sagwon Ecotype Sagwon_Ecotype_Spectral_Data_Metadata Sagwon_Ecotype_170725_Images 133    
Sagwon LEAF - Plant Leaf Spectra Sagwon_LEAF_Spectral_Data_Metadata Sagwon_Leaf_170725_Images 30    
Toolik Ecotype Toolik_Ecotype_Spectral_Data_Metadata Toolik_Ecotype_170726_Images 17    
Toolik LEAF - Plant Leaf Spectra readme_Toolik_LEAF_Spectral_Data_Metadata Toolik_Leaf_170724_Images 82    
Toolik MISP- Mobile Instrumented Sensor Platform Toolik_MISP_Spectral_Data_Metadata   45    
Toolik         CALM- Circumpolar Active Layer Monitoring 64

(*) Includes general site coordinates.

 

Data Dictionary for files sel_2017_spectral_library_svc_data.csv  (2,258 observations) and sel_2018_spectral_library_svc_data.csv  (1,130 observations).

Column number Column name Units/format Description
1 unique_id   Unique row identifier that is the concatenation of location_site_plot_type_date_time_measurement for this observation. There is a matching row of metadata in the corresponding *.metadata.csv file.
2 - 995 wavelengths, 338.1 - 2516.3 nm Each column contains the reflectance values for the respective wavelength that is the column name. There are 994 columns with intervals between columns ranging from 1.5 - 3.9 nm.

 

Data Dictionary for files sel_2017_spectral_library_svc_metadata.csv  (2,258 observations) and sel_2018_spectral_library_svc_metadata.csv  (1,130 observations).

Column name Units/format Description
location_site_plot_type_date_time_measurement   Unique row identifier that is the concatenation of location_site_plot_type_date_time_measurement for this observation. There is a matching row of reflectance data in the corresponding *_spectral_library_svc_data.csv file.
location   Location Name
site_name   Site Name
target_name   Target Name
target_scale_level   Target Scale Level. PL=plot, LF=leaf, MD=??? 
measurement_date yyyy-mm-dd Measurement Date
measurement_time_of_day_(utc)  Hh:mm:ss Measurement Time
measurement_type    Measurement Quantity. Scale for spectral instensity (e.g. DN, radiance, irradiance, reflectance)
proj_title   Project Title
proj_funding_agency   Funding Source
proj_award   Funding Source Grant Number
proj_funding_country   Country
proj_start_year  yyyy Start Year
proj_end_year  yyyy End Year
proj_initiative   Initiative
proj_discipline   Theme. Research context for the spectral measurements. Agriculture, Biochemistry, Ecology, Forest, Global Change, Land Cover, Other, Phenology, Physiology, Water Quality
proj_contact_name   Contact Name
proj_contact_role   Contact role
proj_contact_email   Contact Email
proj_institution   Institution
proj_page_link   Website
proj_keywords   Keywords
site_country   Site Country
site_start_year  yyyy Year
site_ecosystem_type   Ecosystem Type. Alpine, Antarctic, Aquatic, Arctic, Arctic Tundra, Coastal, Crops, Desert, Estuary, Forest, Freshwater, Grassland, Lake, Marine, Montane, Ocean, Pond, Rainforest, River, Savanna, Scrubland, Shrubland, Steppe, Tundra, Urban, Woodland
latitude  Decimal degrees  Latitude
longitude  Decimal degrees  Longitude
measurement_method   Acquisition Method. Minimum measurement unit for your spectra (i.e. contact probe, proximal with X-degree foreoptic, pixel, other).
sample_platform   Sample Platform. Platform from which the spectral measurements were made (e.g. handheld, boom, tram, UAV).
measurement_venue   Measurement Venue. Setting in which the spectral measurements were made. Greenhouse, Laboratory, Other, Outdoor
target_status   Target Status. State of the measurement target.  Dried, Fresh, Green, Ground, Liquid, Live, Other, Panel, Standard
wavelength_units   Wavelength Units. Wavelength units (e.g. nm, um, Hz)
light_source   Light Source. Description of the light source used for your spectral measurements. Lamp, Laser, Other, Sun
instrument_manufacturer   Instrument Manufacturer. Spectrometer manufacturer.
instrument_model   Instrument Model. Spectrometer model.
calibration   Calibration (Spectralon Ratio)
data_type   Data Type (processed)
processing_averaged Y,N Processing Averaged. Is the measurement an average of multiple measurements?
processing_interpolated Y,N Processing Interpolated. Is the measurement interpolated?
processing_resampled Y,N Processing Resampled. Is the measurement resampled? (e.g. are multiple wavelengths averaged?)
processing_software    Processing software

 

 

Application and Derivation

The use of consistent sampling methods and data and metadata structures that follow Ecological Spectral Information System (EcoSIS) Spectral Library (https://ecosis.org/) standards ensures comparability of results across sites within this study and across all EcoSIS library data. Full-spectrum (350-2500 nm) reflectance measurements of plant communities at the leaf and plot scales enables integration with other remotely sensed spectral data for scaling up to watershed, regional, and global scale earth system models.

Quality Assessment

This dataset contain raw reflectance spectra for various tundra vegetation plots and species leaves and has not been analyzed or processed to quantify uncertainty.

Data Acquisition, Materials, and Methods

Sites

Full-spectrum (350-2500 nm) reflectance measurements of diverse plant communities at the plot-level and individual plant species at the leaf-level, were collected at multiple sites across northern Alaska during the 2017 and 2018 summer field seasons. General locations and specific sites are listed in Table 2. The latitude and longitude of each in situ measurement or collected leaf sample is include in the metadata files. The coordinates were acquired using either a DGPS or handheld GPS.

Measurements

In situ reflectance measurements were collected using a HR-1024i spectrometer and data were calibrated using a Spectralon white reference panel during sampling to correct for changing light conditions. Sampling methods and data and metadata structure follow that of Ecological Spectral Information System (EcoSIS) Spectral Library (https://ecosis.org/).

Leaf spectral reflectance scans were collected in a controlled lab setting using a HR-1024i spectrometer, leaf-clip and fibers. Data were calibrated using a Spectralon white reference panel included in the leaf clip. Samples were collected and scanned the same day during the 2017 summer growing season.

Readme Files

Readme files with general site descriptions and coordinates and measurement plot details or leaf scanning details were prepared for those data and samples collected at established sites. See Table 2.

Those sites and measurements that do not have readme files indicate that the measurements were either at new plots or were simply of interest to the project to collect and don’t necessarily pertain to any specific site. In many cases data were collected to expand the spectral library in an effort to capture as much vegetation diversity as possible.

Images

Photographs of plots, plants, and leaf samples were generally taken. See Table 2.

Please be aware that individual image files (*.jpg) are not always named by site – plot within the site collection. But also note, that the order of the in-situ measurement plot photos in a site collection, matches the order of the site - plot measurements in the metadata and data files.

 

Examples of Readme files:

Below are excerpts of content from selected Readme files and Related Photographs for typical measurement and sample types.

 

Leaf Clips:  readme_Atqasuk_LEAF_Spectral_Data.txt

DATA OVERVIEW

This dataset represents full spectrum (i.e. 350 - 2500nm) leaf spectral reflectance data for species located in Atqasuk, Alaska. Scans were collected in a controlled lab setting using a HR-1024i spectrometer, leaf-clip and fibers. Samples were collected and scanned the same day during the 2017 summer growing season and acquired data were calibrated using a Spectralon white reference panel included in the leaf clip.

Site description:

Leaf samples were collected within a 50 meter squared area radius surrounding the Mobile Instrumented Sensor Platform (MISP) transect (2 x 50 meters). These transects were established at various locations throughout the Arctic

leaf photo

Figure 2. Display of leaf and sample measurement metadata..Source: Atqasuk_Leaf_170805_Images/DSCN5738.JPG

leaf plot

Figure 3. Field plot photo for source of leaf sample. Source: Atqasuk_Leaf_170805_Images /DSCN5685.JPG

 

In situ Plot Measurements: readme_Atqasuk_MISP_Spectral_Data.txt

DATA OVERVIEW

This dataset represents full-spectrum (i.e. 350-2500nm) plot-level spectral reflectance data along the Mobile Instrumented Sensor Platform (MISP) transect in Atqasuk, Alaska.

Site description:

Mobile Instrumented Sensor Platform (MISP) transects (2 x 50 meters) were established at various locations throughout the Arctic as a contribution to the US Arctic Observing Network (AON),(Healey, N.C., et al. 2014). Each 50 meter transect was divided into smaller 1 x 2 meter plots and marked with white wooden boards secured to the tundra with 12” metal stakes. The robotic sensor systems collect high spatial and temporal resolution environmental data across a multitude of vegetation functional types and spanning a moisture and latitudinal gradient across the Arctic.

Spatial resolution: spectral reflectance point samples for an approximate 1 meter squared area.

in situ plot

Figure 4. Typical in situ measurement plot photo. Area is approximately 1 m2. Source: Atqasuk_MISP_All_Dates_Images/O_3-4.JPG

 

In situ Plant Measurements: readme_Utqiagvik_Pfrigidus_Spectral_Data_Metadata.txt

DATA OVERVIEW

This dataset represents full-spectrum (i.e. 350-2500nm) plot-level spectral reflectance data of Petasites frigidus growing near the Mobile Instrumented Sensor Platform (MISP) transect in Utqiagvik, Alaska.

Site description:

Mobile Instrumented Sensor Platform (MISP) transects (2 x 50 meters) were established at various locations

Spatial resolution: average spectral reflectance for an approximate 1 meter squared area.

plant plot

Figure 5. Photo of in situ measurement plot with predominately Petasites frigidus. Area is approximately 1 m2. Source: Utqiagvik_PetFri_170810_Images/DSCN6002.JPG

 

 

Data Access

These data are available through the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

ABoVE: Reflectance Spectra of Tundra Plant Communities across Northern Alaska

Contact for Data Center Access Information:

References

Ecological Spectral Information System (EcoSIS) Spectral Library. (https://ecosis.org/)