SNF Site Characterization Validation Data Set Guide Document
Summary:
This data set documentation is currently in work. In the interim, an
abstract of the entire Superior National Forest (SNF) data collection
activity from which the SNF Site Characterization Validation Data Set
is a product is being provided.
During the summers of 1983 and 1984, the National Aeronautics and
Space Administration (NASA) conducted an intensive experiment in a
portion of the Superior National Forest (SNF) near Ely, Minnesota,
USA. The purpose of the experiment was to investigate the ability of
remote sensing to provide estimates of biophysical properties of
ecosystems, such as leaf area index (LAI), biomass and net primary
productivity (NPP). The study area covered a 50 x 50 km area centered
at approximately 48 degrees North latitude and 92 degrees West
longitude in northeastern Minnesota at the southern edge of the North
American boreal forest. The SNF is mostly covered by boreal forest.
Boreal forests were chosen for this project because of their relative
taxonomic simplicity, their great extent, and their potential
sensitivity to climatic change. Satellite, aircraft, helicopter and
ground observations were obtained for the study area.
These data comprise a unique dataset for the investigation of the
relationships between the radiometric and biophysical properties of
vegetated canopies. This is perhaps the most complete dataset of its
type ever collected over a forested region. A key goal of the
experiment was to use the aircraft measurements to scale up to
satellite observations for the remote sensing of biophysical
parameters.
Table of Contents:
1. Data Set Overview
2. Investigator(s)
3. Theory of Measurements
4. Equipment
5. Data Acquisition Methods
6. Observations
7. Data Description
8. Data Organization
9. Data Manipulations
10. Errors
11. Notes
12. Application of the Data Set
13. Future Modifications and Plans
14. Software
15. Data Access
16. Output Products and Availability
17. References
18. Glossary of Terms
19. List of Acronyms
20. Document Information
1. Data Set Overview:
Data Set Identification:
SNF Site Characterization Validation.
Data Set Introduction:
These data comprise a unique dataset for the investigation of the
relationships between the radiometric and biophysical properties of
vegetated canopies. This is perhaps the most complete dataset of its
type ever collected over a forested region.
Objective/Purpose:
The purpose of this study was to investigate the ability of remote
sensing to provide estimates of biophysical properties of ecosystems,
such as leaf area index (LAI), biomass and net primary productivity
(NPP). A key goal of the experiment was to use the aircraft
measurements to scale up to satellite observations for the remote
sensing of biophysical parameters.
Summary of Parameters:
This data set includes the following information: coverage by
vegetation, diameter at breast height, biomass, leaf area index, NPP,
understory leaf extension, canopy coverage, reflectance and
transmittance.
Discussion:
This data set documentation is currently in work. In the interim, an
abstract of the entire Superior National Forest (SNF) data collection
activity from which the SNF Site Characterization Validation data set
is a product is being provided.
In the interim, we are providing an abstract of the entire Superior
National Forest (SNF) data collection activity from which the SNF Site
Characterization Validation data set is a product that we have
incorporated into the ORNL DAAC search and order systems.
During the summers of 1983 and 1984, the National Aeronautics and
Space Administration (NASA) conducted an intensive experiment in a
portion of the Superior National Forest (SNF) near Ely, Minnesota,
USA. The purpose of the experiment was to investigate the ability of
remote sensing to provide estimates of biophysical properties of
ecosystems, such as leaf area index (LAI), biomass and net primary
productivity (NPP). The study area covered a 50 x 50 km area centered
at approximately 48 degrees North latitude and 92 degrees West
longitude in northeastern Minnesota at the southern edge of the North
American boreal forest. The SNF is mostly covered by boreal forest.
Boreal forests were chosen for this project because of their relative
taxonomic simplicity, their great extent, and their potential
sensitivity to climatic change. Satellite, aircraft, helicopter and
ground observations were obtained for the study area. These data
comprise a unique dataset for the investigation of the relationships
between the radiometric and biophysical properties of vegetated
canopies. This is perhaps the most complete dataset of its type ever
collected over a forested region.
Detailed vegetation data were collected on the ground for about 100
sampled sites. These sites represent a range of stand density and age
for spruce and aspen and also include jackpine and mixed stands. At
each site, five circular subplots of 16 meters in diameter were
sampled within a large plot of 60 meters in diameter. Within the
subplots, all woody stems over 2 meters in height were tallied by
species, diameter, and height. Within each subplot, coverage by
vegetation was determined for the canopy, subcanopy and understory.
Thirty each of black spruce and aspen trees from outside the plots
were sacrificed and dimension analysis relations developed between
diameter at breast height, biomass and leaf area index. Also,
above-ground NPP was estimated for each test site. For the aspen
sites, bark area and understory leaf area indexes were found. During
the spring, measurements of understory leaf extension and canopy
coverage were made on several days to describe the phenology of an
aspen stand.
Measurements of the optical properties of canopy components were made
for wavelengths between 0.35 and 2.1 micrometers. Reflectance and
transmittance properties of leaves and needles of eight major
overstory tree species and three understory shrubs were measured.
Multiple measurements of aspen and spruce allow an investigation of
the variability of optical properties within a species, spagnum moss
and leaf litter. Above-canopy reflectance was observed by a
helicopter-mounted Barnes Modular Multiband Radiometer (MMR). The
helicopter MMR data have a spatial resolution of approximately 32
meters. In 1983, 10 days of data were collected between May and
October, with a total of 105 sites observed. In 1984, 8 days of data
were collected between May and September, with a total of 29 sites
observed. Several sites have multiple observations, to allow studies
of seasonal variation. Thematic Mapper Simulator (TMS) data were
collected from the NASA C-130 flying over the SNF. The flights were in
a 'criss-cross' pattern to allow observation of the same location with
multiple sun and view angles. The TMS scans out to 50 degrees off
nadir; in flights at 5000 feet above ground level, a nadir pixel
covers 3.81 meters along the scan. Three days of TMS data are
presented; these data have been atmospherically corrected and
calibrated to determine surface reflectance. A key goal of the
experiment was to use the aircraft measurements to scale up to
satellite observations for the remote sensing of biophysical
parameters.
Related Data Sets:
Not available.
2. Investigator(s):
Investigator(s) Name and Title:
Dr. Forrest G. Hall
NASA Goddard Space Flight Center
Dr. K. Fred Huemmrich
NASA Goddard Space Flight Center
Dr. Donald E. Strebel
Versar, Inc.
Dr. Scott J. Goetz
Universtity of Maryland
Ms. Jaime E. Nickeson
NASA Goddard Space Flight Center
Dr. Kerry D. Woods
Bennington College
Dr. Celeste Jarvis
NASA Headquarters
Title of Investigation:
Biophysical, Morphological, Canopy Optical Property, and Productivity
Data on the Superior National Forest.
Contact Information:
Dr. Forrest G. Hall
NASA Goddard Space Flight Center
Code 923
Greenbelt, Maryland 20771
USA
Fax +1 (301) 286-0239
Telephone +1 (301) 286-2974
Email: fghall@ltpmail.gsfc.nasa.gov
3. Theory of Measurements:
Not available.
4. Equipment:
Sensor/Instrument Description:
Collection Environment:
Ground-based.
Source/Platform:
Field Investigation.
Source/Platform Mission Objectives:
Not available.
Key Variables:
* Forest composition/structure
* Litter characteristics
* Scattering
Principles of Operation:
Not available.
Sensor/Instrument Measurement Geometry:
Not available.
Manufacturer of Sensor/Instrument:
Not available.
Calibration:
Not available.
5. Data Acquisition Methods:
Not available.
6. Observations:
Data/Field Notes:
Not available.
7. Data Description:
Spatial Characteristics:
The study area covered a 50 x 50 km area centered at approximately 48
degrees North latitude and 92 degrees West longitude in northeastern
Minnesota at the southern edge of the North American boreal forest.
Temporal Characteristics:
During the summers of 1983 and 1984, the National Aeronautics and
Space Administration (NASA) conducted an intensive experiment in a
portion of the Superior National Forest (SNF) near Ely, Minnesota,
USA.
Data Characteristics:
__________________________________________________________________________
Variable Name/ Long Name SAS Type Generic Type
Description
__________________________________________________________________________
1 grid_id GRID_ID $ 5 CHAR(5)
"Grid ID"
__________________________________________________________________________
2 plot_id PLOT_ID 8 NUMBER(3,0)
"Plot ID within the site"
__________________________________________________________________________
3 photo_id PHOTO_ID 8 NUMBER(4,0)
"Photo ID for site location"
__________________________________________________________________________
4 obs_datc OBS_DATE $ 12 DATE
"Observation date in DD-MON-YY
format (e.g. 01-JAN-90)"
__________________________________________________________________________
5 pct_rock PCT_ROCK 8 NUMBER(3,0)
"Percent of ground cover that is
rock"
__________________________________________________________________________
6 pct_soil PCT_SOIL 8 NUMBER(3,0)
"Percent of ground cover that is
bare soil"
__________________________________________________________________________
7 pct_herb PCT_HERB 8 NUMBER(3,0)
"Percent of ground cover that is
herbaceous matter"
__________________________________________________________________________
8 pct_shrb PCT_SHRUB 8 NUMBER(3,0)
"Percent of ground cover that is
low shrubs"
__________________________________________________________________________
9 pct_othr PCT_OTHER 8 NUMBER(3,0)
"Percent of ground cover that is
other materials (identified by
OTHER_ID)"
__________________________________________________________________________
10 other_id OTHER_ID $ 12 CHAR(12)
"Other ground cover: water,
dead matter, etc."
__________________________________________________________________________
11 shrbspec SHRUB_SPECIES $ 6 CHAR(6)
"Shrub species code (see SNF
plant species reference file,
spec_ref.dat)"
__________________________________________________________________________
12 shrbcvr SHRUB_COVER 8 NUMBER(3,0)
"Percent of coverage of the low
shrub layer that is specified by
SHRUB_SPECIES for the plot"
__________________________________________________________________________
13 subcspec SUBCAN_SPECIES $ 6 CHAR(6)
"Subcanopy species code (see
SNF plant species reference file,
spec_ref.dat)"
__________________________________________________________________________
14 subc_cvr SUBCAN_COVER 8 NUMBER(3,0)
"Percent of coverage of the
subcanopy layer that is specified
by SUBCAN_SPECIES for the plot"
__________________________________________________________________________
15 subcstem SUBCAN_STEMS 8 NUMBER(3,0)
"Number of tree stems of subcanopy
species specified by SUBCAN_SPECIES
within a 2 meter radius of the plot
center"
__________________________________________________________________________
16 subc_ht SUBCAN_HEIGHT 8 NUMBER(3,0)
"Average height of subcanopy species
specified by SUBCAN_SPECIES within a
2 meter radius of the plot center"
__________________________________________________________________________
17 can_spec CANOPY_SPECIES $ 6 CHAR(6)
"Canopy species code (see SNF plant
species reference file, spec_ref.dat)"
__________________________________________________________________________
18 prismcnt PRISM_COUNT 8 NUMBER(3,0)
"The BAF prism count of all tree
stems for the species specified by
CANOPY_SPECIES"
__________________________________________________________________________
19 can_clos CANOPY_CLOSURE 8 NUMBER(4,0)
"Percent canopy closure of entire
overstory of plot"
__________________________________________________________________________
20 grid_n 8
"Grid ID (numeric for sorting)"
__________________________________________________________________________
21 plot_n 8
"Plot ID (numeric for sorting)"
_________________________________________________________________
Sample Data Record:
Not available at this time.
8. Data Organization:
Not available.
Data Granularity:
A general description of data granularity as it applies to the IMS
appears in the EOSDIS Glossary.
Data Format:
The data files associated with this data set consist of numeric and
character fields of varying lengths aligned in columns. The first row
of each data file contains the 8 character SAS variable name that
links to the data format definition file. Character fields are
enclosed in double quotes and numeric fields are listed without
quotes.
Missing data values can be of two varieties:
1. Values that were identified as missing in the original data files.
Missing numeric values of this type are identified in these data
as -999.
2. Those holes that were created as a result of combining files that
contained a slightly different variable set. Missing values of
this type are identified in these data files as empty double
quotes for character fields and a single period, '.' for numeric
fields.
9. Data Manipulations:
Not available.
10. Errors:
Sources of Error:
Not available.
Quality Assessment:
Data Validation by Source:
Not available.
Confidence Level/Accuracy Judgment:
Not available.
Measurement Error for Parameters:
Not available.
Additional Quality Assessments:
Not available.
Data Verification by Data Center:
The Superior National Forest data was received from the Goddard Space
Flight Center in three media:
* As data dumps from the original Oracle SNF database maintained by
GSFC, transferred electronically from the GSFC system to the ORNL
system;
* As ASCII files that mirrored the tables published in the Tech
Memo; and
* As hard copy (Tech Memo).
Data from both electronic sources were input into SAS by ORNL DAAC
data management staff and compared using computer code developed to
process the SNF data. In many cases, the data values from both sources
were found to be identical. In some cases, however, differences were
identified and the providers of the data were consulted to resolve
inconsistencies.
Additionally, some variable columns were available in one source, but
not the other for various reasons. For example, some calculated
variables/columns were provided in the ASCII files (reflecting the
Tech Memo tables) that were not stored in the Oracle database for
purposes of space conservation.
For similar reasons, coded values were used for many of the site and
species identifier variables. A separate reference table was provided
to link the coded variable with its definition, e.g., the SPECIES_REF
file and the SITE_REF file.
The database produced by the ORNL DAAC is a hybrid product that is a
composite of data and information extracted from all three source
media. In data sets where coded variables were included, the code
definition variables have been added to improve usability of the data
set as a stand-alone product.
Therefore the ASCII files that are available through the ORNL DAAC
on-line search and order systems are output from a data set that is a
product of the essential core of numeric data provided by the data
source (GSFC), augmented with additional descriptive information
provided by GSFC and reorganized by the ORNL DAAC into a data
structure consistent with other similar data sets maintained by the
ORNL DAAC.
11. Notes:
Limitations of the Data:
Not available.
Known Problems with the Data:
None known at this revision.
Usage Guidance:
Not available.
Any Other Relevant Information about the Study:
None.
12. Application of the Data Set:
The aircraft measurements in this data set can be used to scale up to
satellite observations for the remote sensing of biophysical
parameters.
13. Future Modifications and Plans:
None known at this revision.
14. Software:
Not available.
15. Data Access:
Contact Information:
ORNL DAAC User Services
P.O. Box 2008
Mail Stop 6407
Oak Ridge National Laboratory
Oak Ridge, TN 37831-6407
Telephone: (423) 241-3952
FAX: (423) 574-4665
Email: ornldaac@ornl.gov
Data Center Identification:
EOSDIS Distributed Active Archive Center
P.O. Box 2008
Mail Stop 6407
Oak Ridge National Laboratory
Oak Ridge, TN 37831-6407
USA
Telephone: (423) 241-3952
FAX: (423) 574-4665
Email: ornldaac@ornl.gov
Procedures for Obtaining Data:
Users may place requests by letter, telephone, electronic mail, FAX,
or personal visit. Data is also available via the World Wide Web at
http://www-eosdis.ornl.gov.
Data Center Status/Plans:
The Superior National Forest Data is available from the ORNL DAAC.
Please contact the ORNL DAAC User Services Office for the most current
information about these data.
16. Output Products and Availability:
Available online, as a computer FTP file (zipped or unzipped), on tape
or IBM-formatted diskettes.
17. References:
Not available.
Archive/DBMS Usage Documentation.
Contact the EOS Distributed Active Archive Center (DAAC) at Oak Ridge
National Laboratory (ORNL), Oak Ridge, Tennessee (see the Data Center
Identification Section). Documentation about using the archive and/or
online access to the data at the ORNL DAAC is not available at this
revision.
18. Glossary of Terms:
A general glossary for the DAAC is located at EOSDIS Glossary.
19. List of Acronyms:
URL
Uniform Resource Locator
A general list of acronyms for the DAAC is available at
http://cdiac.esd.ornl.gov/cdiac/pns/acronyms.html.
20. Document Information:
Document Revision Date:
Not available.
Document Review Date:
March 3, 1997.
Document ID:
ORNL-SNF_SITE_86.
Citation:
Please cite the following NASA Technical Memorandum 104568 in any work
or any publication using these data:
Hall, F.G., K.F. Huemmrich, D.E. Strebel, S.J. Goetz, J.E. Nickeson,
and K.D. Woods, July 1992. Biophysical, Morphological, Canopy Optical
Property, and Productivity Data From the Superior National Forest.
NASA Technical Memorandum 104568. National Aeronautics and Space
Administration, Washington, D.C. 20546.
Document Curator:
Donna O. Lambert
dlambert@daacs.esd.ornl.gov
Document Author: Merilyn J. Gentry
mjg@walden.rmt.utk.edu
Document URL:
http://www-eosdis.ornl.gov /SNF/guides/site_char_valid.html
_________________________________________________________________
SNF Home Page | Oak Ridge DAAC Home Page | ORNL Home Page
ORNL DAAC User Services Office: 423-241-3952; email
ornldaac@ornl.gov
Web Document Curator: Sarah Jennings, xqj@ornl.gov
Document Editor: Donna Lambert Revision Date: September 24, 1997
URL: http://www-eosdis.ornl.gov /SNF/guides/site_char_valid.html