NASA/TM--2000-209891, Vol. 68

Technical Report Series on the

Boreal Ecosystem-Atmosphere Study (BOREAS)

Forrest G. Hall and Jaime Nickeson, Editors

Volume 68

BOREAS RSS-16 AIRSAR CM Images:

Integrated Processor Version 6.1 Level-3b

Sasan Saatchi, Jet Propulsion Laborato_, Pasadena, California

Jeffrey A. Newcomer and Richard Strub, Raytheon ITSS

Fred lrani, Hughes STX

National Aeronautics and

Space Administration

Goddard Space Flight Center

Greenbelt, Maryland 20771

August 2000

https://ntrs.nasa.gov/search.jsp?R=20010004617 2018-05-14T14:52:34+00:00Z
NASA Center for AeroSpace Information

7121 Standard Drive

Hanover, MD 21076-1320

Price Code: A17

Available from:

National Technical Information Service

5285 Port Royal Road

Springfield, VA 22161

Price Code: A10
BOREAS RSS-16 AIRSAR CM Images: Integrated Processor Version 6.1

Level-3b

Sasan Saatchi, Jeffrey A. Newcomer, Richard Strub, Fred Irani

Summary

The BOREAS RSS-16 team used satellite and aircraft SAR data in conjunction with various ground

measurements to determine the moisture regime of the boreal forest. RSS-16 assisted with the

acquisition and ordering of NASA JPL AIRSAR data collected from the NASA DC-8 aircraft. The

NASA JPL AIRSAR is a side-looking imaging radar system that utilizes the SAR principle to obtain

high-resolution images that represent the radar backscatter of the imaged surface at different

frequencies and polarizations. The information contained in each pixel of the AIRSAR data represents

the radar backscatter for all possible combinations of horizontal and vertical transmit and receive

polarizations (i.e., HH, HV, VH, and VV). Geographically, the data cover portions of the BOREAS

SSA and NSA. Temporally, the data were acquired from 12-Aug-1993 to 31-Ju1-1995. The level-3b

AIRSAR CM data are in compressed Stokes matrix format, which has 10 bytes per pixel. From this

data format, it is possible to synthesize a number of different radar backscatter measurements. The data

are stored in binary image-format files.

Note that the level-3b AIRSAR data are not contained on the BOREAS CD-ROM set. An inventory

listing file is supplied on the CD-ROM to inform users of the data that were collected. See Sections 15

and 16 for information about how to acquire the data.

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

Page 1
1. Data Set Overview

1.1 Data Set Identification

BOREAS RSS-16 AIRSAR CM Images: Integrated Processor Version 6.1 Level-3b

1.2 Data Set Introduction

The BOReal Ecosystem-Atmosphere Study (BOREAS) Staff Science effort covered those activities

that were BOREAS community-level activities or required uniform data collection procedures across

sites and time. These activities included the acquisition of the relevant aircraft image data. Data from

the Airborne Synthetic Aperture Radar (AIRSAR) system onboard the National Aeronautics and Space

Administration (NASA) DC-8 aircraft were acquired by staff at the Jet Propulsion Laboratory (JPL)

and provided for use by BOREAS researchers.

The level-3b AIRSAR Compressed Matrix (CM) data set described here was produced at the JPL

Synthetic Aperture Radar (SAR) processing facility and delivered to the BOREAS Information System

(BORIS) on CD-ROM. This data set represents a replacement to the CM data previously delivered to

BORIS. In February of 1998, after the AIRSAR data had been delivered to BORIS, documented,

inventoried, and delivered to Oak Ridge National Laboratory (ORNL), we.received a letter from JPL

notifying us that they had discovered and resolved a problem in the AIRSAR Integrated Processor

Versions 5.01 and 5.02, with which BOREAS data had been processed. At this time, the AIRSAR

program management offered to reprocess all delivered data with a new processor. This data set

represents the reprocessed data, processed with the AIRSAR Integrated Processor Version 6.1.

1.3 Objective/Purpose

The purpose of this data set is to provide multifrequency and multipolarization SAR images over

the BOREAS Southern Study Area (SSA). This data set supplements other visible and near-infrared

remote sensing images compiled by BOREAS. The level-3b AIRSAR data were acquired at three

frequencies of P-band, L-band, and C-band and for all linear polarization combinations (HH, HV,

VH, and VV). The level-3b AIRSAR CM image data products contain data from all 12 frequency and

polarization combinations. AIRSAR images are used to estimate surface parameters such as canopy

water content, soil moisture, and stand biomass and density.

1.4 Summary of Parameters

SAR parameters: incidence angle, aircraft altitude, range resolution, azimuth resolution, frequency,

polarization.

1.5 Discussion

AIRSAR image data gathering for BOREAS was conducted in 1993 and 1994 over the two study

areas in Canada. BOREAS was designed to study regional land surface climatology and to develop

methods for deriving quantitative information about surface variables from remote sensing data. The

AIRSAR experiment was devised to provide surface moisture and vegetation variables suitable for the

soil-vegetation-atmosphere interaction models. In particular, the high-resolution data obtained by the

AIRSAR system can be used to derive information about the variability of the surface parameters,

which in turn can be used to address the scaling problem.

1.6 Related Data Sets

BOREAS RSS-16 Level-3b DC-8 AIRSAR SY Images

Page 2
2. Investigator(s)

2.1 Investigator(s) Name and Title

Dr. Sasan S. Saatchi

2.2 Title of Investigation

Estimation of Evapotranspiration Using SAR Derived Parameters

2.3 Contact Information

Contact 1:

Dr. Sasan S. Saatchi

Jet Propulsion Laboratory

Mail Stop 300-243

4800 Oak Grove Drive

Pasadena, CA 91109

(818) 354-1051

saatchi@ bacchus.jpl.nasa.gov

Contact 2:

Dr. Jakob J. vanZyl

Jet Propulsion Laboratory

Mail Stop 300-243

4800 Oak Grove Drive

Pasadena, CA 91109

(818) 354-1365

Contact 3:

Jaime Nickeson

Raytheon ITSS

NASA GSFC

Code 923

Greenbelt, MD 20771

(301) 286-3373

(301) 286-0239 (fax)

Jaime.Nickeson@gsfc.nasa.gov

3. Theory of Measurements

The basic quantity measured by a polarimetric radar is a complex (amplitude and phase) scattering

matrix for each resolution element of the radar image. This implies that AIRSAR is a multichannel

system designed to maintain phase coherence between radar antennas and different channels. The

polarization states used in the AIRSAR system are based on horizontal and vertical antennas. The radar

is configured to measure all possible combinations available from the horizontal (H) and vertical (V)

antennas (i.e., H transmitting, H receiving, and so forth). The complete scattering matrix for a

resolution element can then be determined. Knowledge of the scattering matrix permits calculation of

the received power for any possible combination.

Page 3
4. Equipment

4.1 Sensor/Instrument Description

SAR refers to a technique used to synthesize a very long antenna by combining signals (echoes)

received by the radar as it moves along its flight track. NASA JPL currently maintains and operates the

AIRSAR/Topographic SAR (TOPSAR), which flies on the NASA DC-8 aircraft.

The AIRSAR system is an airborne SAR that operates simultaneously in a fully polarimetric mode

at three frequencies (P-, L-, and C- bands). JPL operates the radar aboard the NASA Ames Research

Center DC-8 aircraft. The data collected by the AIRSAR system are processed to polarimetric imagery

at JPL and provided to BORIS in digital and photographic forms. The AIRSAR system provides

several output products, including real-time imagery and the final processed digital products. Two of

the most common digital products are the CM products and the Synoptic (SY) products.

The real-time imagery is provided to the investigators for a SAR pass. This is a low-resolution,

black-and-white, single-frequency/polarization (typically LHH) image of the entire pass. No digital

data of this type are provided. Annotation of the image allows the investigators to select areas for

further processing. The information on the data includes run name (name assigned to the data

acquisition pass, typically the site name), Greenwich Mean Time (GMT) (day of year followed by

GMT), A/C Lat-Lon, frame count, and frequency/polarization.

The standard AIRSAR CM product consists of a 16-look (20-MHz) or 8-look (40-MHz)

"polarization compressed" digital file on tape for each frequency (for input to polarization synthesis

software provided by JPL) and a color photo product. The frame product corresponds to about 12 km

along-track of imagery by 10-15 km across-track. As part of the standard products, the data sets are

calibrated by the ground SAR processor.

During the 1993 experiment, only limited data were collected over the BOREAS study areas. In

1994, a large amount of imagery was collected and is summarized in Section 7 below. In 1995, a

special collection effort was planned to collect imagery over an area of the SSA that had been burned

the previous season.

4.1.1 Collection Environment

The AIRSAR system operates within the fuselage of the DC-8 aircraft during flight. The AIRSAR

was flown at medium altitudes aboard NASA's DC-8 aircraft based at NASA's JPL and provided

11-m slant range resolution at an altitude of 8000 m.

4.1.2 Source/Platform

NASA DC-8 aircraft.

4.1.3 Source/Platform Mission Objectives

The objective was to acquire multipolarization and multifrequency SAR images over the BOREAS

study areas and transect region.

4.1.4 Key Variables

Polarization, radar frequency, radar look angle, aircraft altitude, range resolution, azimuth

resolution, site lat-long coordinates, aircraft geometry.

4.1.5 Principles of Operation

The NASA JPL AIRSAR is a side-looking imaging radar system that utilizes the SAR principle to

obtain high-resolution images that represent the radar backscatter of the imaged surface at different

frequencies and polarizations.

4.1.6 Sensor/Instrument Measurement Geometry

During the BOREAS experiment, the instrument was located in the NASA DC-8 aircraft

approximately 7,800 m above ground. The antennas are located on the port side of the aircraft looking

at an angle over the site. The nominal pointing angle was 28 degrees, which covered the ground

surface from approximately 28 to 72 degrees. All DC-8 AIRSAR CM level-3b images are produced at

Page 4
6 m inrangeand12m inazimuthresolutions.

4.1.7 Manufacturer of Sensor/Instrument

Jet Propulsion Laboratory

4800 Oak Grove Drive

Pasadena, CA 91109

(818) 354-4321

4.2 Calibration

4.2.1 Specifications

In one mode of operation, this system is capable of simultaneously collecting all four polarizations

(HH, HV, VH, and VV) for three frequencies: L-band (lambda ~ 24 cm), C-band (lambda ~ 6 cm),

and P-band (lambda ~ 68 cm). In another mode of operation, the AIRSAR/TOPSAR system collects

all four polarizations (HH, HV, VH, and VV) for two frequencies: L-band (lambda - 24 cm) and

P-band (lambda - 68 cm), while operating as an interferometer at C-band to simultaneously generate

topographic height data.

AIRSAIUTOPSAR also has an along-track interferometer mode that is used to measure current

speeds. Typical image sizes for AIRSAR/TOPSAR products are 12 km x 12 km, with 10-m resolution

in both dimensions. Topographic map products generated by the TOPSAR system have been shown to

have a height accuracy of 1 m in relatively flat areas and 5 m in mountainous areas.

4.2.1.1 Tolerance

Each image contains detailed calibration information in the header information area.

4.2.2 Frequency of Calibration

Much of the data produced by the AIRSAR are now calibrated, so that the radar backscatter

measurements are in normalized radar cross-section format (m2/m2) or 0"0 (sigma zero). Sigma zero is

the radar cross-section (measured in m2) normalized by the area of the measurement, which in this case

is the pixel area in square meters.

4.2.3 Other Calibration Information

Two types of complementary calibration techniques are used for AIRSAR data calibration: intemal

calibration and external calibration. For the internal calibration, the information collected from the

system tests that are performed regularly during the flight is used to obtain calibration parameters to be

used in the AIRSAR processor. This will ensure that all the polarization channels are calibrated relative

to one another at each frequency. For external calibration, which calibrates the radar cross-section of

the scene absolutely and removes channel imbalance and the cross-talk, information from the scene and

dihedral comer reflectors as external targets is used. Investigators who are interested in checking the

accuracy of the calibration and performing other corrections themselves can request a copy of the

POLCAL software and the user's manual directly from JPL.

5. Data Acquisition Methods

The AIRSAR system acquires data during flights of the DC-8 aircraft. The instrument system acquires

the data across the various spatial elements while the aircraft motion provides the forward motion for

image acquisition.

Page 5
6.1 Data Notes

None given.

6.2 Field Notes

None given.

6. Observations

7. Data Description

7.1 Spatial Characteristics

7.1.1 Spatial Coverage

The BOREAS AIRSAR CM Level-3b images cover sections of the SSA and the Northern Study

Area (NSA). The SSA and the NSA are located in the southwest and northeast portions of the overall

BOREAS region.

Each image covers a 12-km along-track and 10-km across-track area. The images contain 1,280

pixels in each of the approximately 5,000 lines.

Most of the BOREAS AIRSAR level-3b CM imagery is over the SSA. There are two early season

dates of level-3b SY imagery of the NSA. The SSA and the NSA are located in the southwest and

northeast portions of the overall region.

The North American Datum of 1983 (NAD83)

corner coordinates of the SSA are:

Latitude Longitude

Northwest 54.321°N I06.228ow

Northeast 54.225°N I04.237ow

Southwest 53.515°N I06.321ow

Southeast 53.420°N I04.368oW

The NAD83 corner coordinates of the NSA are:

Latitude Longitude

Northwest 56.249°N 98.825ow

Northeast 56.083°N 97.234ow

Southwest 55.542°N 99.045ow

Southeast 55.379°N 97.489°W

7.1.2 Spatial Coverage Map

Not available.

7.1.3 Spatial Resolution

Resolution in range: 6.66 m (across-track). Resolution in azimuth: 12.27 m (along-track).

7.1.4 Projection

The Remote Sensing Science (RSS)-16 team informed BORIS personnel that the images have been

resampled into a regular spatial grid; however, the details of the projection used are not known.

7.1.5 Grid Description

The RSS-16 team informed BORIS personnel that the images have been resampled into a regular

spatial grid; however, the details of the gridding are not known.

Page 6
7.2 Temporal Characteristics

7.2.1 Temporal Coverage

The AIRSAR CM level-3b data were collected during concentrated periods from 12-Aug-1993 to

31-Ju1-1995.

7.2.2 Temporal Coverage Map

Date Study Area

12-Aug-1993 SSA

ll-Jun-1994 SSA

17-Apr-1994 NSA

17-Apr-1994 SSA

20-Apr-1994 NSA

21-Jui-1994 SSA

22-Apt-1994 SSA

23-Jui-1994 SSA

26-Apr-1994 SSA

28-Jui-1994 SSA

31-Jui-1995 SSA

7.2.3 Temporal Resolution

Most of the SSA Modeling Sub-Area (MSA) was covered by the AIRSAR CM images on two or

three occasions from 12-Aug- 1993 to 31 -Jul- 1995.

7.3 Data Characteristics

7.3.1 Parameter/Variable

The data files contain a mixture of character and binary components. The user is encouraged to

contact JPL personnel for detailed format descriptions. For the most part, the actual image data are

INTEGER*2 in a format compatible with Sun computer systems. The parameters contained in the

inventory listing file on the CD-ROM are:

Column Name

SPATIAL COVERAGE

DATE OBS

TIME OBS

PLATFORM

INSTRUMENT

NUM BANDS

PLATFORM ALTITUDE

NW LATITUDE

NW LONGITUDE

NE LATITUDE

NE LONGITUDE

SW LATITUDE

SW LONGITUDE

SE LATITUDE

SE LONGITUDE

JPL PRODUCT ID

CRTFCN CODE

Page 7
7.3.2 Variable Description/Definition

To translate the integer*2 values supplied in the file to radar cross-sections, one has to apply the

following calculation:

(DN^2)/(General scale factor)

where the General scale factor is the general scale factor supplied in field 2 of the calibration header.

The descriptions of the parameters contained in the inventory listing file on the CD-ROM are:

Column Name Description

SPATIAL COVERAGE

DATE OBS

TIME OBS

PLATFORM

INSTRUMENT

NUM BANDS

PLATFORM ALTITUDE

NW_LATITUDE

NW LONGITUDE

NE LATITUDE

NE LONGITUDE

SW LATITUDE

SW LONGITUDE

SE LATITUDE

SE LONGITUDE

JPL PRODUCT ID

CRTFCN CODE

The general term used to denote the spatial area

over which the data were collected.

The date on which the data were collected.

The Greenwich Mean Time (GMT) when the data were

collected.

The object (e.g., satellite, aircraft, tower,

person) that supported the instrument.

The name of the device used to make the

measurements.

The number of spectral bands in the data.

The nominal altitude of the data collection

platform above the target.

The NAD83 based latitude coordinate of the northwest corner of the minimum bounding rectangle

for the data.

The NAD83 based longitude coordinate of the

northwest corner of the minimum bounding

rectangle for the data.

The NAD83 based latitude coordinate of the north

east corner of the minimum bounding rectangle for

the data.

The NAD83 based longitude coordinate of the

north east corner of the minimum bounding

rectangle for the data.

The NAD83 based latitude coordinate of the south

west corner of the minimum bounding rectangle for

the data.

The NAD83 based longitude coordinate of the

southwest corner of the minimum bounding

rectangle for the data.

The NAD83 based latitude coordinate of the south

east corner of the minimum bounding rectangle for

the data.

The NAD83 based longitude coordinate of the

southeast corner of the minimum bounding

rectangle for the data.

The JPL Radar Data Center product identifier.

The BOREAS certification level of the data.

Examples are CPI (Checked by PI), CGR (Certified

by Group), PRE (Preliminary), and CPI-??? (CPI

but questionable).

Page 8
7.3.3 Unit of Measurement

The image values are stored as the amplitude, i.e. as the square root of the power reflected back

from the target. The measurement units for the parameters contained in the inventory listing file on the

CD-ROM are:

Column Name

..............................

SPATIAL COVERAGE [none]

DATE OBS [DD-MON-YY]

TIME OBS [HHMM GMT]

PLATFORM [none]

INSTRUMENT [none]

NUM BANDS [counts]

PLATFORM ALTITUDE [meters]

NW LATITUDE [degrees]

NW LONGITUDE [degrees]

NE LATITUDE [degrees]

NE LONGITUDE [degrees]

SW LATITUDE [degrees]

SW LONGITUDE [degrees]

SE LATITUDE [degrees]

SE LONGITUDE [degrees]

JPL PRODUCT ID [none]

CRTFCN CODE [none]

Units

7.3.4 Data Source

The imagery were collected by the AIRSAR sensor aboard the NASA DC-8 research aircraft and

were processed and provided by the Radar Data Center at the Jet Propulsion Laboratory, Pasadena,

California. The sources of the parameter values contained in the inventory listing file on the CD-ROM

are"

Column Name Data Source

SPATIAL COVERAGE [Derived by BORIS from the image data

DATE OBS [Extracted from the image data files]

TIME--OBS [Extracted from the image data files]

PLATFORM [Constant value]

INSTRUMENT [Constant value]

NUM BANDS [Extracted from the image data files]

PLATFORM ALTITUDE [Extracted from the image data files]

NW LATITUDE [Derived by BORIS developed software]

NW--LONGITUDE [Derived by BORIS developed software]

NE--LATITUDE [Derived by BORIS developed software]

NE--LONGITUDE [Derived by BORIS developed software]

SW--LATITUDE [Derived by BORIS developed software]

SW--LONGITUDE [Derived by BORIS developed software]

SE--LATITUDE [Derived by BORIS developed software]

SE--LONGITUDE [Derived by BORIS developed software]

JPL PRODUCT ID [Extracted from the image data files]

CRTFCN CODE [Assigned by BORIS]

files]

Page 9
7.3.5 Data Range

Typically radar images exhibit a dynamic range less than 30 dB. Therefore each data set is scaled by

a single value for all pixels such that the dynamic range of the total power elements in the Stokes

matrices falls within values between 2-128 and 2127. The total power for each matrix is then coded

into two bytes, one for the exponent in the above range and one for the mantissa. The other eight

elements stored in the 10-byte sample are then normalized. The following table gives information about

the parameter values found in the inventory table on the CD-ROM:

Column Name

Minimum Maximum Missng Unrel Below Data

Data Data Data Data Detect Not

Value Value Value Value Limit Cllctd

SPATIAL COVERAGE N/A N/A None None None None

DATE OBS 12-AUG-93 31-JUL-95 None None None None

TIME OBS 910 2141 None None None None

PLATFORM DC-8 DC-8 None None None None

INSTRUMENT N/A N/A None None None None

NUM BANDS 3 3 None None None None

PLATFORM ALTITUDE 7397.7 7770.5 None None None None

NW LATITUDE 53.9064 56.16305 None None None None

NW LONGITUDE -106.96903 -98.40082 None None None None

NE LATITUDE 53.85669 55.98273 None None None None

NE LONGITUDE -106.0159 -97.0018 None None None None

SW LATITUDE 53.46364 55.99398 None None None None

SW LONGITUDE -107.03206 -98.44842 None None None None

SE LATITUDE 53.41428 55.83307 None None None None

SE LONGITUDE -106.09375 -97.01739 None None None None

JPL PRODUCT ID N/A N/A None None None None

CRTFCN CODE CPI CPI None None None None

Minimum Data Value -- The minimum value found in the column.

Maximum Data Value -- The maximum value found in the column.

Missng Data Value -- The value that fndicates missing data. This is used to

indicate that an attempt was made to determine the

parameter value, but the attempt was unsuccessful.

Unrel Data Value -- The value that indicates unreliable data. This is used

to indicate an attempt was made to determine the

parameter value, but the value was deemed to be

unreliable by the analysis personnel.

Below Detect Limit -- The value that indicates parameter values below the

instruments detection limits. This is used to

indicate that an attempt was made to determine the

parameter value, but the analysis personnel determined

that the parameter value was below the detection

limit of the instrumentation.

Data Not Cllctd -- This value indicates that no attempt was made to

determine the parameter value. This usually

indicates that BORIS combined several similar but

not identical data sets into the same data base table

but this particular science team did not

measure that parameter.

Blank -- Indicates that blank spaces are used to denote that type of value.

N/A -- Indicates that the value is not applicable to the respective column.

None -- Indicates that no values of that sort were found in the column.

Page 10
7.4 Sample Data Record

A sample data record for the level-3b AIRSAR SY images is not available here. The following is a

sample of the first few records from the level-3b AIRSAR CM inventory table on the CD-ROM:

SPATIAL COVERAGE,DATE OBS,TIME OBS,PLATFORM, INSTRUMENT,NUM_BANDS,

PLATFORM ALTITUDE,NW LATITUDE,NW LONGITUDE,NE LATITUDE,NE_LONGITUDE, SW_LATITUDE,

SW LONGITUDE, SE LATITUDE,SE LONGITUDE, JPL PRODUCT ID,CRTFCN_CODE

,SSA,,12-AUG-93,1604, 'DC-8', 'AirSAR',3,74OI.3,54.18676,-106.96903,54.15057,

-i06.0159,53.5401,-i07.03206,53.50446,-i06.09375, '5408', 'CPI'

,SSA,,12-AUG-93,1633, 'DC-8', 'AirSAR',3,7479.3,54.12961,-106.81807,54.09205,

-105 86264,53.4834,-i06.88333,53.44641,-I05.94272, '5396', 'CPI'

'SSA ,12-AUG-93,1700, 'DC-8', 'AirSAR',3,7494.4,54.18495,-I06.6663,54.1459,

-105 70355,53.53942,-I06.73396,53.50095,-i05.78614, '5399', 'CPI'

'SSA ,12-AUG-93,1713, 'DC-8', 'AirSAR',3,7502.7,54.15652,-106.07887,54.11219,

-105 i0684,53.50504,-i06.15637,53.46139,-I05.19952, '5398', 'CPI'

8. Data Organization

8.1 Data Granularity

The smallest unit of data tracked by BORIS was a particular level-3b CM image.

8.2 Data Format(s)

The CD-ROM inventory listing file consists of numerical and character fields of varying length

separated by commas. The character fields are enclosed with single apostrophe marks. There are no

spaces between the fields.

Since detailed format information on the AIRSAR data is available from JPL, BORIS personnel

have not provided an exhaustive description of the data here. Please contact JPL personnel for further

details.

The AIRSAR Integrated Processor Version 6.1 product received from JPL on CD-ROM contains

seven files for each acquisition. The files of primary interest for data users are the P, L, and C

frequency bands, named *_p.dat, *_L.dat, and *_C.dat, respectively. The other files are *.r, *.g, and

a *.b files, which are the red, green, and blue files, respectively, used to create the browse prints

(*.gif file), also included. In some cases a *.moc file is included, which is a motion data file, but this

was included inconsistently and unintentionally.

Each record of a level-3b AIRSAR CM data file contains 10,240 bytes. The first three records in

each file contain header information. The number of data records in a file varies depending on the

length of the flight line. Each data record of 10,240 bytes contains a portion of the compressed Stokes

matrix data. More specific information is as follows:

FILE 1 (the entire scene, headers and image data, is contained in a single file)

C-band records:

JPL AIRSAR New Header Record (Logical Record I)

* 20 records, each containing 50 ASCII characters.

* Remainder of the logical record (24,600 bytes) is filler.

JPL AIRSAR Parameter Header Record (Logical Record 2)

* i00 records, each containing 50 ASCII characters.

* Remainder of record (20,600 bytes) is filler.

JPL AIRSAR Calibration Header Record (Logical Record 3)

* 20 records, each containing 50 ASCII characters.

* Remainder of record (24,600 bytes) is filler.

Page 11
JPL AIRSAR CM Compressed Stokes matrix data records

(Logical Record 4 to the end of the band). The end of the band can

be determined by using the first five parameters (logical record size,

nHeader recs, nLines, nSamples, nBytes per sample) listed in the New

Header Record:

logical rec size * (nHeader recs - # already read(3)) +

nLines * nSamples * nBytes per sample

Physical Record Size

Example:

25600 * (6-3) + 6699 * 2560 * I0

1024

L-band records:

JPL AIRSAR New Header Record (Logical Record i)

* 20 records, each containing 50 ASCII characters.

* Remainder of the logical record (24,600 bytes) is filler.

JPL AIRSAR Parameter Header Record (Logical Record 2)

* i00 records, each containing 50 ASCII characters.

* Remainder of record (20,600 bytes) is filler.

- JPL AIRSAR Calibration Header Record (Logical Record 3)

* 20 records, each containing 50 ASCII characters.

* Remainder of record (24,600 bytes) is filler.

JPL AIRSAR CM Compressed Stokes matrix data records

(Logical Record 4 to the end of the band). The end of the band can

be determined by using the first five parameters (logical record size,

nHeader recs, nLines, nSamples, nBytes per sample) listed in the New

Header Record:

logical rec size * (nHeader recs - # already read(3)) +

nLines * nSamples * nBytes per sample

Physical Record Size

P-band records:

JPL AIRSAR New Header Record (Logical Record i)

* 20 records, each containing 50 ASCII characters.

* Remainder of the logical record (24,600 bytes) is filler.

JPL AIRSAR Parameter Header Record (Logical Record 2)

* i00 records, each containing 50 ASCII characters.

* Remainder of record (20,600 bytes) is filler.

JPL AIRSAR Calibration Header Record (Logical Record 3)

* 20 records, each containing 50 ASCII characters.

* Remainder of record (24,600 bytes) is filler.

Page 12
JPL AIRSAR CM Compressed Stokes matrix data records

(Logical Record 4 to the end of the band). The end of the band can

be determined by using the first five parameters (logical record size,

nHeader recs, nLines, nSamples, nBytes per sample) listed in the New

Header Record:

logical rec size * (nHeader recs - # already read(3)) +

nLines * nSamples * nBytes per sample

Physical Record Size

9. Data Manipulations

9.1 Formulae

None.

9.1.1 Derivation Techniques and Algorithms

None given.

9.2 Data Processing Sequence

9.2.1 Processing Steps

BORIS staff makes the AIRSAR CM level-3b images available by"

• Duplicating the JPL delivered images for backup purposes.

• Extracting pertinent header information from the images for use in inventorying the level-3b

image by date and time in the online data base.

• Reviewing the content of the extracted header information for potential problems/anomalies.

• Loading the needed information into the online data base.

9.2.2 Processing Changes

In early 1998, a problem was found in the AIRSAR Integrated Processor Versions 5.01 and 5.02.

This problem affected the backscatter cross-section o'-0values in some of the BOREAS products.

BORIS personnel have sent both the 5.0x and 6.1 versions of the data to the ORNL DAAC. Users are

encouraged to be sure they get the most recent version of the images that were contained on CD-ROM.

9.3 Calculations

9.3.1 Special Corrections/Adjustments

None given.

9.3.2 Calculated Variables

None given.

9.4 Graphs and Plots

None.

Page 13
10. Errors

10.1 Sources of Error

In early 1998, a problem was found in the AIRSAR Integrated Processor Versions 5.01 and 5.02.

This problem affected the backscatter cross section o'-0 values in some of the BOREAS products.

BORIS personnel have sent both the 5.0x and 6.1 versions of the data to the ORNL DAAC. Users are

encouraged to be sure they get the most recent version of the images that was contained on CD-ROM.

10.2 Quality Assessment

10.2.1 Data Validation by Source

None given.

10.2.2 Confidence Level/Accuracy Judgment

None given.

10.2.3 Measurement Error for Parameters

None given.

10.2.4 Additional Quality Assessments

None given.

10.2.5 Data Verification by Data Center

BORIS staff reviews the images using developed software that was designed based on data

product format documents received from JPL. The software reads through the data products on tape

and summarizes the contents in ASCII files on disk. These files are reviewed visually by BORIS

personnel for anomalous items.

11. Notes

11.1 Limitations of the Data

None given.

11.2 Known Problems with the Data

The data are provided in two different formats (see Section 8.2). Also see Section 9.2.2.

11.3 Usage Guidance

In early 1998, a problem was found in the AIRSAR Integrated Processor Versions 5.01 and 5.02.

This problem affected the backscatter cross section er0 values in some of the BOREAS products.

BORIS personnel have sent both the 5.0x and 6.1 versions of the data to the ORNL DAAC. Users are

encouraged to be sure they get the most recent version of the images that were contained on CD-ROM.

11.4 Other Relevant Information

None given.

12. Application of the Data Set

AIRSAR images are used to estimate surface parameters such as canopy water content, soil moisture,

and stand biomass and density.

Page 14
None.

13. Future Modifications and Plans

14. Software

14.1 Software Description

BORIS staff developed software and command procedures to:

• Check and extract information from level-3b AIRSAR CM images on tape and write the

information to ASCII files on disk for both data formats.

° Read the ASCII disk file and log the level-3b AIRSAR CM images into the Oracle data base

tables.

The software mentioned under items 1 and 2 is written in the C language and is operational on VAX

6410 and MicroVAX 3100 systems at Goddard Space Flight Center (GSFC). The primary

dependencies in the software are the tape input/output (I/O) library and the Oracle data base utility

routines.

14.2 Software Access

All of the described software is available upon request. BORIS staff would appreciate knowing of

any problems discovered with the software, but cannot promise to fix them.

15. Data Access

The level-3b AIRSAR CM images are available from the Earth Observing System Data and

Information System (EOSDIS) ORNL Distributed Active Archive Center (DAAC).

15.1 Contact Information

For BOREAS data and documentation please contact:

ORNL DAAC User Services

Oak Ridge National Laboratory

P.O. Box 2008 MS-6407

Oak Ridge, TN 37831-6407

Phone: (423) 241-3952

Fax: (423) 574-4665

E-mail: omldaac@ornl.gov or ornl@eos.nasa.gov

15.2 Data Center Identification

Earth Observing System Data and Information System (EOSDIS) Oak Ridge National Laboratory

(ORNL) Distributed Active Archive Center (DAAC) for Biogeochemical Dynamics

http://www-eosdis.oml.gov/.

15.3 Procedures for Obtaining Data

Users may obtain data directly through the ORNL DAAC online search and order system

[http://www-eosdis.oml.gov/] and the anonymous FTP site [ftp._//www-eosdis.oml.gov/data/] or by

contacting User Services by electronic mail, telephone, fax, letter, or personal visit using the contact

information in Section 15.1.

Page 15
15.4 Data Center Status/Plans

The ORNL DAAC is the primary source for BOREAS field measurement, image, GIS, and

hardcopy data products. The BOREAS CD-ROM and data referenced or listed in inventories on the

CD-ROM are available from the ORNL DAAC.

16. Output Products and Availability

16.1 Tape Products

The AIRSAR level-3b CM data can be made available on 8-mm or Digital Archive Tape (DAT)

media.

16.2 Film Products

None.

16.3 Other Products

Although the inventory is contained on the BOREAS CD-ROM set, the actual level-3b AIRSAR

CM images are not. See Section 15 for information about how to obtain the data.

During the data acquisition flight, 35-mm photographs were taken of the areas imaged by the

AIRSAR system. Anyone interested in these photographs should contact Dr. Sasan Saatchi (see

Section 2.3.)

17. References

17.1 Platform/Sensor/Instrument/Data Processing Documentation

Freeman, T. 1998. What is Imaging Radar? JPL Imaging Radar.

NASA JPL. Date unknown. "AIRSAR Data Formats," Chapter 4.

NASA JPL. 1995. AIRSAR Integrated Processor Documentation: DATA FORMATS. Version 0.01.

17.2 Journal Articles and Study Reports

Newcomer, J., D. Landis, S. Conrad, S. Curd, K. Huemmrich, D. Knapp, A. Morrell, J. Nickeson,

A. Papagno, D. Rinker, R. Strub, T. Twine, F. Hail, and P. Sellers, eds. 2000. Collected Data of The

Boreal Ecosystem-Atmosphere Study. NASA. CD-ROM.

Sellers, P. and F. Hall. 1994. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version

1994-3.0, NASA BOREAS Report (EXPLAN 94).

Sellers, P. and F. Hall. 1996. Boreal Ecosystem-Atmosphere Study: Experiment Plan. Version

1996-2.0, NASA BOREAS Report (EXPLAN 96).

Sellers, P., F. Hail, and K.F. Huemmrich. 1996. Boreal Ecosystem-Atmosphere Study: 1994

Operations. NASA BOREAS Report (OPS DOC 94).

Sellers, P., F. Hall, and K.F. Huemmrich. 1997. Boreal Ecosystem-Atmosphere Study: 1996

Operations. NASA BOREAS Report (OPS DOC 96).

Sellers, P., F. Hall, H. Margolis, B. Kelly, D. Baldocchi, G. den Hartog, J. Cihlar, M.G. Ryan, B.

Goodison, P. Crill, K.J. Ranson, D. Lettenmaier, and D.E. Wickland. 1995. The boreal

ecosystem-atmosphere study (BOREAS): an overview and early results from the 1994 field year.

Bulletin of the American Meteorological Society. 76(9): 1549-1577.

Page 16
Sellers,P.J.,F.G.Hall, R.D.Kelly, A. Black,D. Baldocchi,J. Berry,M. Ryan,K.J. Ranson,P.M.

Crill, D.P.Lettenmaier,H. Margolis,J.Cihlar,J.Newcomer,D. Fitzjarrald,P.G.Jarvis,S.T.

Gower,D. Halliwell,D. Williams,B. Goodison,D.E.Wickland,andF.E.Guertin.1997.BOREAS

in 1997:ExperimentOverview,ScientificResultsandFutureDirections.Journalof Geophysical

Research102(D24):28,731-28,770.

vanZyl, J. 1992.TheAIRSARSystem.JPLdocument.

vanZyl, J. 1995.AIRSARIntegratedProcessorDocumentation,Version0.01,April 21.

17.3 Archive/DBMS Usage Documentation

None.

None.

18. Glossary of Terms

AIRSAR

ASCII

BOREAS

BORIS

BPI

CCT

CD-ROM

CM

DAAC

DAT

EOS

EOSDIS

GMT

GSFC

JPL

MSA

NAD83

NASA

NSA

ORNL

PANP

RSS

SAR

SSA

SY

TOPSAR

URL

19. List of Acronyms

- Airborne Synthetic Aperture Radar

- American Standard Code for International Interchange

- BOReal Ecosystem-Atmosphere Study

- BOREAS Information System

- Bytes per inch

- Computer Compatible Tape

- Compact Disk - Read-Only Memory

- Compressed Matrix

- Distributed Active Archive Center

- Digital Archive Tape

- Earth Observing System

- EOS Data and Information System

- Greenwich Mean Time

- Goddard Space Flight Center

- Jet Propulsion Laboratory

- Modeling Sub-Area

- North American Datum of 1983

- National Aeronautics and Space Administration

- Northern Study Area

- Oak Ridge National Laboratory

- Prince Albert National Park

- Remote Sensing Science

- Synthetic Airborne Radar

- Southern Study Area

- Synoptic

- Topographic SAR

- Uniform Resource Locator

Page 17
20. Document Information

20.1 Document Revision Dates

Written: 31-Jul- 1995

Last Updated: 23-Sep- 1999

20.2 Document Review Date

BORIS Review: 05-May- 1998

Science Review:

20.3 Document ID

20.4 Citation

When using these data, please include the following acknowledgment as well as citations of

relevant papers in Section 17.2:

The AIRSAR data were provided by the Radar Data Center at NASA's Jet Propulsion Laboratory.

Also, cite the BOREAS CD-ROM set as:

Newcomer, J., D. Landis, S. Conrad, S. Curd, K. Huemmrich, D. Knapp, A. Morrell, J.

Nickeson, A. Papagno, D. Rinker, R. Strub, T. Twine, F. Hall, and P. Sellers, eds. Collected Data of

The Boreal Ecosystem-Atmosphere Study. NASA. CD-ROM. NASA, 2000.

20.5 Document Curator

20.6 Document URL

Page 18

Form Approved

REPORT DOCUMENTATION PAGE oe8 No. o7o4-o188

Publicreportingburdenforthis collectionof informationis estimated to average 1 hourper response,includingthe timefor reviewinginstructions,searchingexistingdata sources,

gathering end maintainingthe data needed, and completingand reviewingthe collection of information. Send commentsregardingthisburdenestimateor anyother aspect of this

collectionof information,includingsuggestionsfor reducingthis burden,to WashingtonHeadquartersServices,Directoratefor InformationOperationsand Reports.1215 Jefferson

Davis Highway,Suite 1204, Arlington,VA 22202-4302, and to the Office of Management and Budget, PaperworkReductionProject(0704-0188), Washington,DC 20503.

1. AGENCY USE ONLY (Leave b/ank) 2. REPORT DATE 3. REPORT TYPE AND DATES COVERED

August 2000 Technical Memorandum

4. TITLE AND SUBTITLE 5. FUNDING NUMBERS

Technical Report Series on the Boreal Ecosystem-Atmosphere Study (BOREAS)

BOREAS RSS-16 AIRSAR CM Images: Integrated Processor Version 6.1 923

Level-3b

6. AUTHOR(S) RTOP: 923-462-33-01

Sasan Saatchi, Jeffrey A. Newcomer, Richard Strub, and Fred Irani

Forrest G. Hall and Jaime Nickeson, Editors

7. PERFORMING ORGANIZATION NAME(S) AND ADDRESS (ES)

Goddard Space Flight Center

Greenbelt, Maryland 20771

9.SPONSORING/ MONITORINGAGENCYNAME(S)AND ADDRESS(ES)

National Aeronautics and Space Administration

Washington, DC 20546-0001

8. PEFORMING ORGANIZATION

REPORT NUMBER

2000-03136-0

10.SPONSORING/MONITORING

AGENCYREPORTNUMBER

TM--2000-209891

Vol. 68

11. SUPPLEMENTARY NOTES

S. Saatchi: Jet Propulsion Laboratory, Pasadena, California; J.A. Newcomer, R. Strub,

and J. Nickeson: Raytheon ITSS; F. Irani: Hughes STX

124. DISTRIBUTION ! AVAILABILITY STATEMENT 12b. DISTRIBUTION CODE

Unclassified-Unlimited

Subject Category: 43

Report available from the NASA Center for AeroSpace Information,

7121 Standard Drive, Hanover, MD 21076-1320. (301) 621-0390.

13. ABSTRACT (Maximum 200 words)

The BOREAS RSS-16 team used satellite and aircraft SAR data in conjunction with various ground

measurements to determine the moisture regime of the boreal forest. RSS-16 assisted with the acquisition and ordering of NASA JPL AIRSAR data collected from the NASA De-8 aircraft. The NASA

JPL AIRSAR is a side-looking imaging radar system that utilizes the SAR principle to obtain highresolution images that represent the radar backscatter of the imaged surface at different frequencies

and polarizations. The information contained in each pixel of the AIRSAR data represents the radar

backscatter for all possible combinations of horizontal and vertical transmit and receive polarizations

(i.e., HH, HV, VH, and VV). Geographically, the data cover portions of the BOREAS SSA and NSA.

Temporally, the data were acquired from 12-Aug-1993 to 31-Jul-1995. The tevel-3b AIRSAR CM data

are in compressed Stokes matrix format, which has 10 bytes per pixel. From this data format, it is

possible to synthesize a number of different radar backscatter measurements. The data are stored in

binary image-format files.

14.SUBJECTTERMS

BOREAS, remote sensing science, SAR, AIRSAR.

17.SECURITYCLASSIFICATION18.SECURITYCLASSIFICATION

OFREPORT OFTHISPAGE

Unclassified Unclassified

NSN7540-01-280-5500

19. SECURITY CLASSIFICATION

OF ABSTRACT

Unclassified

15. NUMBER OF PAGES

18

16. PRICE CODE

20. LIMITATION OF ABSTRACl

UL

Standard Form 298 (Rev. 2-89)

Prescribedby ANSI Std. Z39.18

298-102