BOREAS TE-12 Leaf Optical Data for SSA Species

Summary

The BOREAS TE-12 team collected several data sets in support of its
efforts to characterize and interpret information on the reflectance,
transmittance, and gas exchange of boreal vegetation. This data set
contains measurements of hemispherical spectral reflectance and
transmittance factors of individual leaves, needles (ages: current and
past 2 years\' growth, i.e., for 1993, the growing seasons of 1993,
1992, and 1991 were measured; in 1994, the growing seasons of 1994,
1993, and 1992 were measured), twigs (reflectance only), and substrate
at near-normal incidence measured using a LI-COR LI-1800-12 integrating
sphere attached to a Spectron Engineering SE590 spectroradiometer.
Procedures of Daughtry et al. (1989) were followed. These procedures
permitted measurement of samples that: 1) filled the entire integrating
sphere sample port, and 2) were narrow with a length greater than the
sample port diameter. Optical properties were measured at the SSA Fen,
YJP, YA, and OBS sites. The data are stored in tabular ASCII files.

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

This data set includes measurements of leaf optical properties of
individual leaves and needles collected during the growing seasons of
1993 and 1994.

1.1 Data Set Identification

BOREAS TE-12 Leaf Optical Data for SSA Species

1.2 Data Set Introduction

Hemispherical spectral reflectance and transmittance factors of
individual leaves, needles (ages: current and past 2 years\' growth,
i.e., for 1993, the growing seasons of 1993, 1992, and 1991 were
measured; in 1994, the growing seasons of 1994, 1993, and 1992 were
measured), twigs (reflectance only) and substrate at near-normal
incidence measured using a LI-COR LI-1800-12 integrating sphere attached
to a Spectron Engineering SE590 spectroradiometer. Each SE590 has a
unique wavelength associated with each of its 252 bands. A cubic spline
interpolation was applied to the 252-bands to standardize the
wavelengths to every 5 nm from 400 to 1000 nm, so that
wavelength-to-wavelength comparisons can be made between SE590s.

1.3 Objective/Purpose

The purpose of this work was to characterize optical properties of
boreal forest canopy and substrate elements.

1.4 Summary of Parameters

Hemispherical reflectance and transmittance factors of needles and twigs
(from current and past years\' growth) and individual leaves and
substrate elements. Measurements were made for both tops and bottoms of
leaves and needles.

1.5 Discussion

Intensive Field Campaign (IFC)-1993:

Optical properties were measured at two sites in the BOReal
Ecosystem-Atmosphere Study (BOREAS) Southern Study Area (SSA): at or
near the Nipawin Fen (FEN) and Nipawin Jack Pine \[Young-Dry\] (YJP).
Canopy access was limited to only ground level collection of samples.
Samples from trees were from various heights within the tree, but
generally were from the lower third of the entire canopy height. Black
spruce \[Picea mariana\], jack pine \[Pinus banksiana\], Labrador tea
\[Ledum groenlandicum\], and aspen \[Populus tremuloides\] were sampled
near the SSA-FEN site. Bog birch \[Betula pumila\], buck bean
\[Menyanthes trifloiate\], marsh marigold \[Caltha palustris\], and
cinquefoil \[Potentilla palustris\] were sampled in the SSA-FEN site.
Jack pine needles and substrate (dead needles, bark, blueberry
\[Vaccinium sp.\], and bearberry \[Arctostaphylos uva-ursi\]) were
sampled at the SSA-YJP site.

Procedures of Daughtry et al. (1989) were followed. These procedures
permitted measurement of two sample types: type 1, which filled the
entire integrating sphere sample port, and type 2, which were narrow
with a length greater than the sample port diameter. One of the two
external light sources was used with the integrating sphere: a standard
illuminator with a beam (11.4-mm diameter spot size) and a modified
illuminator with a restricted beam spot (slitted illuminator\--3.5-mm x
11-mm spot size). Sample type 1 used the standard light source, while
sample type 2 used either the standard or the modified light source
depending on sample length.

Optical properties measured for sample type 1 were reflectance and
transmittance of the adaxial (top) and abaxial (bottom) surfaces.
Measurement procedures limited to sample type 2 reflectance and
transmittance measurements to only one surface of a sample; generally,
the adaxial surface was measured.

Focused Field Campaign (FCC)-Winter (W):

Optical properties were measured at two sites in the SSA: Old Jack Pine
(OJP) and Old Black Spruce (OBS). The measurement methods described
above were used. Jack pine trees were sampled at SSA-OJP, and black
spruce trees were sampled at SSA-OBS. Adaxial and abaxial surfaces of
the needles were measured.

FFC-Thaw (T):

Optical properties were measured at two sites in the SSA: OJP and OBS.
Jack pine trees were sampled at SSA-OJP, and black spruce trees were
sampled at SSA-OBS. Measurements were made following the modified
procedures of Daughtry et al. (1989) in which an image analysis system
was used to measure the nonintercepted illumination beam. Reflectance
and transmittance of the adaxial and abaxial surfaces of the samples
were measured.

IFC-1, #-2, and #-3:

Optical properties were measured at five sites in the SSA: YJP, FEN,
OBS, Old Aspen (OA), and Young Aspen (YA). Jack pine, bearberry, and
fuzzy-spiked wild rye \[Elymus Innovatus\] and some substrate components
(dead needles and bark) were sampled at SSA-YJP. Bog birch (of various
senescing stages), buck bean, and a sedge \[Carex sp.\] were measured at
SSA-FEN. Black spruce, wildrose \[Rosa woodsii\], Labrador tea \[Ledum
groenlandicum\], and blueberry were sampled at SSA-OBS. Mature aspen was
measured at SSA-OA during IFC-1 only. Young aspen, hazelnut \[Corylus
cornuta\], alder \[Alnus crispa\], and balsam poplar \[Populus
balsamifera\] were measured at the SSA-YA (IFC-2 and -3); aspen,
hazelnut, and balsam poplar were measured at various senescent stages
during IFC-3 only.

Optical properties were measured following the modified procedures of
Daughtry et al. (1989). An image analysis system was used to measure the
nonintercepted illumination beam area. Reflectance and transmittance of
the adaxial (top) and abaxial (bottom) surfaces were measured for sample
types 1 and 2. Generally, the adaxial surface was measured.

1.6 Related Data Sets

BOREAS TE-12 SSA Shoot Geometry Data

BOREAS TE-12 SSA Water Potential Data

BOREAS TE-10 Leaf Optical Properties

2\. Investigator(s)

2.1 Investigator(s) Name and Title.

Elizabeth A. Walter-Shea

Associate Professor

2.2 Title of Investigation

Radiation and Gas Exchange of Canopy Elements in a Boreal Forest

2.3 Contacts Information

[Contact 1]{.underline}:

Mark A. Mesarch

University of Nebraska- Lincoln

Lincoln, NE

\(402\) 472-5904

\(402\) 472-0284

\(402\) 472-6614 (fax)

mmesarch@unlinfo.unl.edu

[Contact 2]{.underline}:

Elizabeth A. Walter-Shea

University of Nebraska- Lincoln

Lincoln, NE

\(402\) 472-1553

\(402\) 472-6614 (fax)

agme012@unlvm.unl.edu

[Contact 3]{.underline}:

Cynthia J. Hays

University of Nebraska- Lincoln

Lincoln, NE

\(402\) 472-6701

\(402\) 472-6614 (fax)

agme025@unlvm.unl.edu

[Contact 4]{.underline}:

Shelaine Curd

Raytheon STX Corporation

NASA GSFC

Greenbelt, MD

\(301\) 286-2447

\(301\) 286-2039 (fax)

shelaine.curd@gsfc.nasa.gov

[Contact 5]{.underline}:

Andrea Papagno

Raytheon STX Corporation

NASA GSFC

Greenbelt, MD

\(301\) 286-3134

\(301\) 286-2039 (fax)

apapagno@pop900.gsfc.nasa.gov

3\. Theory Of Measurements

Leaves, needles, and bark are canopy elements that are important in
scattering radiation in boreal forest vegetation (Norman and Jarvis,
1974). Needle and bark properties can vary considerably depending on age
and height in the canopy; elements deep in the canopy may be covered
with algae and fungi, and shade-induced effects on shoot development may
exist (Norman and Jarvis, 1974; Smith and Carter, 1988). In the
near-infrared portion of the electromagnetic spectrum, little radiation
is absorbed; thus, scattering by canopy elements will be significant. In
contrast, leaves and needles absorb a large portion of
photosynthetically active radiation (PAR) (Daughtry et al., 1989;
Williams, 1991). Conifer needles absorb more PAR than deciduous leaves;
twigs, especially the current year\'s growth, also absorb PAR (Williams,
1991). Thus, the scattering component of PAR may be small except in
sparse canopies with high underlying surface albedo.

In the LI-COR 1800-12 integrating sphere (LI-COR, Inc., Lincoln,
Nebraska), the sample is held to the outside of the sphere, with a small
section of the sample acting as part of the sphere wall. The interior of
the sphere is coated with barium sulfate to make a uniform diffuse
reflector. In this type of sphere, the sensor, in this case the SE590,
does not directly observe the sample. The field of view of the sensor is
a section of the sphere wall.

To calculate reflectance, a comparison of the wall illumination caused
by a beam of radiation reflected by the sample material to that
reflected from the reference material is calculated. The LI-COR 1800-12
uses the same illumination source for both cases. The source is moved
between ports to illuminate the sample and reference material. Under
ideal conditions, the sample reflectance is given by the ratio of the
illuminated sample output and the reference output. In reality, other
factors must be considered. First, the reference material is not a
perfect reflector. Also, not all of the incoming radiation beam hits the
sample or reference; some radiation is scattered off of the sphere walls
without hitting the target. Finally, adjustments must be made if the
sample does not cover the entire port of the integration sphere.

Transmittance is calculated by comparing the wall illumination from
radiation passed through the sample to the illumination when no sample
was present. As with reflectance measurements, corrections must be made
to the ideal case. Daughtry et al. (1989) describes the measurement
methods for the three cases of leaf sizes. Case 1 is for leaves that can
completely cover the sample port of the integration sphere; case 2 is
for leaves that are too narrow to cover the sample port but are long
enough to be attached to a sample holder outside of the view through the
sample port.

The difficulty in determining the reflectance and transmittance of
leaves that are too small to cover the sample port (case 2) is that what
is observed in the sample port now consists of a combination of the
leaves and the material between the leaves; air for case 2. The problem
in this case is to determine the area of leaves covering the sample port
and adjust the measured reflected and transmitted fluxes by that
fractional area. The fractional area of the needles was determined using
a solid-state camera. The image of the sample was transferred to a PC,
where the areas were calculated.

4.Equipment

4.1 Instrument Description

The Spectron Engineering SE590 is a portable battery- or A/C-operated
spectroradiometer consisting of a CE500 data analyzer/logger controller,
CE390 spectral detector head, and an external battery charger/power
supply. The CE500 is a self-contained microprocessor-based controller
that processes the signal from the detector head, amplifying and
digitizing it with 12-bit resolution. For each spectral scan, the
controller actuates the CE390 shutter, measures and stores the dark
current, calculates optimum integration time, acquires the spectrum, and
automatically subtracts the noise for all 256 spectral elements. A
series of scans can be taken and automatically averaged; for these
measurements, four scans were averaged for full leaf samples and eight
scans were averaged for all other samples. The entire 12-bit binary
spectrum is stored in a double-precision register until it is
transmitted through the RS-232C port. The spectral detector head uses a
diffraction grating as the dispersive element; the spectrum is imaged
onto a 256-element photodiode array. Each element integrates
simultaneously, acquiring the spectrum in a fraction of a second. The
interconnect cable from the spectral head to the controller couples the
spectral signals to the controller, and the timing and control signals
to the detector head. A shutter in the detector head, operated by the
controller, closes the light path for dark current measurements. For
further information, consult the SE590 operating manual. Serial Number
1571 was used.

The LI-COR LI-1800-12 Integrating Sphere is an instrument for collecting
radiation that has been reflected from or transmitted through a sample
material. An external light source illuminates a spot on the sample.
Either a standard light source (11.4-mm diameter) or a modified light
source that restricts the illumination spot size (3.5-mm x 11-mm) was
used. The lamp used in the external light source is a 6-Volt 10-Watt
glass-halogen. For a further description, see the LI-COR Integrating
Sphere Instruction Manual. Serial Number IS115-8304 was used in 1993,
and IS319 was used in 1994.

An image analysis system was used to measure the gaps between sample
elements (e.g., needles, twigs) when a sample did not fill the entire
integrating sphere sample port or a single sample element was too narrow
to be completely encompassed by the modified light source.

A Coho solid-state camera (model 4812-2000/ES16) with a 60-mm focal
1ength:2.8 Nikon lens was used to view a sample. A near-infrared filter
was added to the lens after 20-August-1994. The camera was mounted
approximately 24.1 cm above the sample. The lens was set at an aperture
of 11 mm.

The sample was placed on a Wolff two-bulb fluorescent light table. Red
transparencies were placed under the sample to restrict the total amount
of light in the system to an area of peak response (608 nm) to avoid
saturating the signal from the camera. After 30-August-1994, a black
cloth was draped around the camera lens down to the light table to
reduce the amount of extraneous light shining on the sample or into the
lens.

A Data Translation frame grabber board (UM-08128-B) was used to input
the signal from the camera to an IBM 80286. SPSS' software JAVA version
1.4 was used to measure the areas of the gaps between needles. The
display monitor was an IBM VGA with 640- by 480- pixels.

4.1.1 Collection Environment

Measurements of black spruce and jack pine needles were made in the
control environment of the laboratory. Aspen leaves were measured
on-site at the SSA-YA and SSA-OA site. Other samples were measured at
the site where they were collected or back at the lab.

4.1.2 Source/Platform

The Spectron Engineering SE590 was connected to the LI-COR integrating
sphere. This assembly was mounted on a camera tripod and adjusted to
ensure that the light source was level.

4.1.3 Source/Platform Mission Objectives

None given.

4.1.4 Key Variables

Specular reflectance, transmittance and absorbance of needle and leaf
elements.

4.1.5 Principles of Operation

The SE590 spectral detector head uses a diffraction grating as the
dispersive element; the spectrum is imaged onto a 256-element photodiode
array. Each element integrates simultaneously, acquiring the spectrum in
a fraction of a second.

The LI-COR LI-1800-12 integrating sphere is an external integrating
sphere, which means that the sample is external to the sphere; when it
is in place, a small part of the sample actually makes up part of the
sphere wall. For further information, see the LI-COR 1800-12 Integrating
Sphere Instruction Manual.

The Cohu solid state camera transmits a signal to the frame grabber
board, which translates the intensity of each pixel to a gray scale from
0 (black) to 255 (white) levels. The JAVA software program was set up to
count the number of pixels in a defined area of interest for a range of
gray scales that represent the \"white\" gaps between the sample needle
elements.

4.1.6 Instrument Measurement Geometry

The SE590 was mounted on the LI-COR LI-1800-12 integrating sphere. A
tripod is attached to the support connecting the SE590 and integrating
sphere. A modified external light source with a slitted beam (3.5 mm x
11 mm) was used to illuminate narrow samples and associated reference. A
standard external light source with a circular beam (11.4-mm diameter
spot size) was used to illuminate all other samples and associated
reference. The light source was kept in a horizontal position according
to integrating sphere manual requirements.

4.1.7 Manufacturer of Instrument

Spectron Engineering SE590 Spectroradiometer:

Spectron Engineering, Inc.

25 Yuma Court

Denver, CO 80223

\(303\) 733-1060

LI-COR LI-1800-12 Integrating Sphere:

LI-COR, Inc.

Box 4425

Lincoln, NE 68504

\(402\) 467-3576

Cohu Solid State Camera:

Cohu, Inc., Electronics Division

5755 Kearny Villa Road

P.O. Box 85623

San Diego, CA 92138-0221

\(619\) 277-6700

\(619\) 277-0221 (fax)

Frame Grabber Board:

Data Translation, Inc.

100 Locke Drive

Marlboro, MA 01752-1192

\(508\) 481-3700

SPSS, Inc.

233 S. Wacker Drive

11th Floor

Chicago, IL 60606-6307

\(800\) 543-2185

\(800\) 841-0064 (fax)

4.2 Calibration

4.2.1 Specifications

Each SE590 has a unique wavelength associated with each of its 252
bands. A cubic spline interpolation was applied to the 252 bands to
standardize the wavelengths to every 5 nm from 400 to 1000 nm, so that
wavelength to wavelength comparisons can be made between SE590s.

4.2.1.1 Tolerance

The SE590 response was checked periodically using neutral density
filters of known transmittances (Mesarch et al., 1991). For all
measurement periods, no corrections were made to the SE590 response,
because mean relative errors were less than 0.2 percent across
wavelengths. The collimation of the LI-COR LI-1800-12 integrating sphere
illuminator was checked daily by making a stray light measurement
(LI-COR, 1983). Results from a temperature dependency study indicate
that measurements at 1000 nm may result in discrepancies of
approximately 50-W/m^2^/sr/µm if the instrument temperature varies for
16 to 43.5 ° C (Blad et al., 1990). The temperature effect should be
negligible because the suite of measurements required to calculate
reflectance and transmittance ratios is acquired in a short period of
time, during which temperature change is minor to nonexistent.

4.2.2 Frequency of Calibration

Transmittance filter tests were conducted before, during, and after
field measurements. A preseason wavelength characterization was
performed at Goddard Space Flight Center (GSFC) in April 1993 and March
1994.

4.2.3 Other Calibration Information

Wavelengths, in nanometers, used for data reduction for IFC-1993 and
FFC-W were:

channel wavelength ch. wavelength ch. wavelength

\-\-\-\-\-\-- \-\-\-\-\-\-\-\-\-- \-\-- \-\-\-\-\-\-\-\-\-- \-\--
\-\-\-\-\-\-\-\-\--

1 369.0514 2 371.7167 3 374.3852

4 377.0569 5 379.7318 6 382.4099

7 385.0912 8 387.7756 9 390.4633

10 393.1541 11 395.8481 12 398.5453

13 401.2457 14 403.9493 15 406.6561

16 409.3661 17 412.0792 18 414.7955

19 417.5151 20 420.2378 21 422.9637

22 425.6928 23 428.4250 24 431.1605

25 433.8992 26 436.6410 27 439.3860

28 442.1342 29 444.8856 30 447.6402

31 450.3980 32 453.1590 33 455.9231

34 458.6905 35 461.4610 36 464.2347

37 467.0116 38 469.7917 39 472.5750

40 475.3615 41 478.1512 42 480.9440

43 483.7400 44 486.5393 45 489.3417

46 492.1473 47 494.9561 48 497.7680

49 500.5832 50 503.4016 51 506.2231

52 509.0478 53 511.8757 54 514.7068

55 517.5411 56 520.3786 57 523.2193

58 526.0631 59 528.9102 60 531.7604

61 534.6138 62 537.4704 63 540.3302

64 543.1932 65 546.0594 66 548.9288

67 551.8013 68 554.6770 69 557.5560

70 560.4381 71 563.3234 72 566.2119

73 569.1035 74 571.9984 75 574.8965

76 577.7977 77 580.7021 78 583.6097

79 586.5205 80 589.4345 81 592.3517

82 595.2721 83 598.1956 84 601.1224

85 604.0523 86 606.9854 87 609.9217

88 612.8612 89 615.8039 90 618.7498

91 621.6989 92 624.6511 93 627.6065

94 630.5652 95 633.5270 96 636.4920

97 639.4602 98 642.4315 99 645.4061

100 648.3839 101 651.3648 102 654.3489

103 657.3362 104 660.3267 105 663.3204

106 666.3173 107 669.3174 108 672.3206

109 675.3271 110 678.3367 111 681.3495

112 684.3655 113 687.3847 114 690.4071

115 693.4327 116 696.4615 117 699.4934

118 702.5285 119 705.5669 120 708.6084

121 711.6531 122 714.7010 123 717.7520

124 720.8063 125 723.8638 126 726.9244

127 729.9882 128 733.0552 129 736.1254

130 739.1988 131 742.2754 132 745.3552

133 748.4381 134 751.5243 135 754.6136

136 757.7061 137 760.8018 138 763.9007

139 767.0028 140 770.1081 141 773.2166

142 776.3282 143 779.4430 144 782.5611

145 785.6823 146 788.8067 147 791.9343

148 795.0650 149 798.1990 150 801.3362

151 804.4765 152 807.6200 153 810.7667

154 813.9166 155 817.0697 156 820.2260

157 823.3855 158 826.5481 159 829.7140

160 832.8830 161 836.0552 162 839.2306

163 842.4092 164 845.5910 165 848.7760

166 851.9642 167 855.1555 168 858.3500

169 861.5478 170 864.7487 171 867.9528

172 871.1601 173 874.3705 174 877.5842

175 880.8011 176 884.0211 177 887.2443

178 890.4707 179 893.7003 180 896.9331

181 900.1691 182 903.4083 183 906.6506

184 909.8962 185 913.1449 186 916.3968

187 919.6519 188 922.9102 189 926.1717

190 929.4364 191 932.7043 192 935.9753

193 939.2495 194 942.5270 195 945.8076

196 949.0914 197 952.3784 198 955.6685

199 958.9619 200 962.2585 201 965.5582

202 968.8611 203 972.1672 204 975.4765

205 978.7890 206 982.1047 207 985.4236

208 988.7456 209 992.0709 210 995.3993

211 998.7309 212 1002.0650 213 1005.4030

214 1008.7440 215 1012.0890 216 1015.4360

217 1018.7870 218 1022.1410 219 1025.4980

220 1028.8590 221 1032.2220 222 1035.5890

223 1038.9590 224 1042.3320 225 1045.7080

226 1049.0870 227 1052.4700 228 1055.8560

229 1059.2450 230 1062.6370 231 1066.0320

232 1069.4310 233 1072.8330 234 1076.2380

235 1079.6460 236 1083.0570 237 1086.4720

238 1089.8890 239 1093.3100 240 1096.7340

241 1100.1620 242 1103.5920 243 1107.0260

244 1110.4620 245 1113.9020 246 1117.3460

247 1120.7920 248 1124.2420 249 1127.6940

250 1131.1500 251 1134.6090 252 1138.0720

Wavelengths, in nanometers, used for data reduction for FFC-T and IFC-1,
-2, and -3 were:

channel wavelength ch. wavelength ch. wavelength

\-\-\-\-\-\-- \-\-\-\-\-\-\-\-\-- \-\-- \-\-\-\-\-\-\-\-\-- \-\--
\-\-\-\-\-\-\-\-\--

1 369.1879 2 371.884 3 374.5831

4 377.285 5 379.9898 6 382.6975

7 385.4081 8 388.1217 9 390.8381

10 393.5574 11 396.2796 12 399.0047

13 401.7327 14 404.4635 15 407.1973

16 409.934 17 412.6736 18 415.4161

19 418.1614 20 420.9097 21 423.6609

22 426.4149 23 429.1719 24 431.9317

25 434.6945 26 437.4601 27 440.2286

28 443.0001 29 445.7744 30 448.5516

31 451.3317 32 454.1147 33 456.9007

34 459.6895 35 462.4812 36 465.2758

37 468.0733 38 470.8737 39 473.6769

40 476.4831 41 479.2922 42 482.1042

43 484.9191 44 487.7368 45 490.5575

46 493.3811 47 496.2075 48 499.0369

49 501.8691 50 504.7043 51 507.5423

52 510.3832 53 513.2271 54 516.0738

55 518.9234 56 521.7759 57 524.6313

58 527.4897 59 530.3509 60 533.215

61 536.082 62 538.9519 63 541.8247

64 544.7003 65 547.5789 66 550.4604

67 553.3448 68 556.2321 69 559.1222

70 562.0153 71 564.9113 72 567.8101

73 570.7119 74 573.6165 75 576.5241

76 579.4345 77 582.3478 78 585.2641

79 588.1832 80 591.1052 81 594.0301

82 596.9579 83 599.8887 84 602.8223

85 605.7588 86 608.6982 87 611.6405

88 614.5857 89 617.5337 90 620.4847

91 623.4386 92 626.3954 93 629.3551

94 632.3176 95 635.2831 96 638.2515

97 641.2227 98 644.1969 99 647.1739

100 650.1539 101 653.1367 102 656.1224

103 659.1111 104 662.1026 105 665.097

106 668.0943 107 671.0945 108 674.0977

109 677.1037 110 680.1126 111 683.1244

112 686.1391 113 689.1567 114 692.1771

115 695.2005 116 698.2268 117 701.256

118 704.2881 119 707.323 120 710.3609

121 713.4017 122 716.4453 123 719.4919

124 722.5413 125 725.5937 126 728.6489

127 731.707 128 734.7681 129 737.832

130 740.8988 131 743.9685 132 747.0411

133 750.1167 134 753.1951 135 756.2764

136 759.3606 137 762.4477 138 765.5377

139 768.6305 140 771.7263 141 774.825

142 777.9266 143 781.0311 144 784.1384

145 787.2487 146 790.3619 147 793.4779

148 796.5969 149 799.7187 150 802.8435

151 805.9711 152 809.1016 153 812.2351

154 815.3714 155 818.5106 156 821.6527

157 824.7977 158 827.9457 159 831.0965

160 834.2502 161 837.4068 162 840.5663

163 843.7287 164 846.8939 165 850.0621

166 853.2332 167 856.4072 168 859.5841

169 862.7638 170 865.9465 171 869.1321

172 872.3205 173 875.5119 174 878.7061

175 881.9033 176 885.1033 177 888.3062

178 891.5121 179 894.7208 180 897.9324

181 901.1469 182 904.3643 183 907.5847

184 910.8079 185 914.034 186 917.263

187 920.4949 188 923.7297 189 926.9673

190 930.2079 191 933.4514 192 936.6978

193 939.9471 194 943.1992 195 946.4543

196 949.7123 197 952.9731 198 956.2369

199 959.5035 200 962.7731 201 966.0455

202 969.3208 203 972.5991 204 975.8802

205 979.1642 206 982.4511 207 985.7409

208 989.0337 209 992.3293 210 995.6278

211 998.9292 212 1002.233 213 1005.54

214 1008.85 215 1012.163 216 1015.479

217 1018.798 218 1022.12 219 1025.444

220 1028.772 221 1032.102 222 1035.435

223 1038.771 224 1042.11 225 1045.452

226 1048.797 227 1052.145 228 1055.496

229 1058.849 230 1062.206 231 1065.565

232 1068.927 233 1072.292 234 1075.66

235 1079.031 236 1082.405 237 1085.782

238 1089.161 239 1092.544 240 1095.929

241 1099.317 242 1102.709 243 1106.103

244 1109.5 245 1112.899 246 1116.302

247 1119.708 248 1123.116 249 1126.528

250 1129.942 251 1133.359 252 1136.78

5\. Data Acquisition Methods

The CANOPY_LOCATION parameter of the data set is a relative measure
based upon the height of the sample location relative to the height of
the canopy. Therefore, a sample collected from the top of a short tree
in a tall canopy and a sample collected from the bottom of a short tree
in a short canopy can both be designated as \"low\" for the HEIGHT
parameter. CANOPY_LOCATION parameters used are HIGH, LOW, MIDDLE,
GROUND, AND UNDER. UNDER refers to an understory component being
measured. GROUND refers to the lower third of the total canopy height.

For IFC-1993 and IFC-1, -2, and -3:

Samples were cut from plants, covered with damp cheesecloth, sealed in a
Ziploc-type storage bag, and stored and transported in a cool ice chest
to the lab for processing. Generally, processing of conifer needles and
twigs required 2 to 3 days to complete. If the samples were not measured
on the same day they were cut from the plant, they were stored in a
refrigerator for processing in the next 1 or 2 days. The cut end of the
samples from YA and FEN (i.e., aspen, bog birch, buck bean, marsh
marigold, cinquefoil, and sedge) were placed in water-filled vials upon
cutting and remained so until completion of optical measurements,
generally within 10 minutes of cutting.

For FFC-W and FFC-T:

Samples were collected from trees and placed in Ziploc-type storage bags
containing damp paper towels. The samples were packed in ice and shipped
to Lincoln, NE, for measurement.

Adaxial leaf surfaces of aspen, buck bean, bog birch, and substrate
element samples typically were brighter in color and had a glossier
sheen than the abaxial surfaces. The abaxial surface of Labrador tea
leaves was heavily pubescent; the current year\'s growth was white
pubescent, and the prior years\' growth having rust-colored pubescent.
The black spruce surface without the whitish lines was defined as the
adaxial surface. Jack pine needles were attached to twigs in paired
fascicles and generally had a semicircular cross-sectional shape. The
outer semicircular convex, curved side of the needle was considered the
adaxial surface. (For a more detailed description of the shape of the
needles, see the BOREAS TE-12 shoot geometry document.)

Approximately 40 needles for a particular age class (e.g., 1994 growth,
1993 growth) were selected from three shoots on a cut sample and placed
in a bag. Needles were randomly sampled from this mixture to produce
three samples per age class.

A sample mount was designed to maintain the sample elements in the same
orientation relative to one another for all measurements. Two types of
sample mounts were constructed, one for each light source. One sample
mount had an aperture the same size as the integrating sphere sample
port and slightly larger than the illumination spot of the full lamp
(e.g., 11.4-mm diameter); the second sample mount had an aperture (5.5
mm x 15 mm) designed to hold the short black spruce needles and slightly
larger than the beam dimensions of the slitted illuminator (3.5 mm x 11
mm) for the integrating sphere. Approximately 6-11 sample elements
(e.g., needles or twigs) were placed on the sample mount using
transparent tape to affix the needle ends to the sample mount in such a

way that the tape would not be visible in the integrating sphere sample
port. The elements were placed so that gaps between elements were
approximately equal. Prior to 20-Jul-1994, elements were spaced a sample
element apart. Samples made after 20-Jul-1994 were constructed so that
the sample elements were evenly spaced, but the fraction of
nonintercepted illumination beam was approximately 5-15-% of the total
beam area.

Stray light was measured at the beginning of each day and/or at the
beginning of a set of measurements with each light source used. The
color of the needles and twigs was coded using the Munsell color chips
(Munsell, 1977) prior to optical measurements. The method of sample
measurement varied based on physical size of the sample element:

For sample type 1, the sample element filled the integrating sphere
sample port (samples included were aspen, hazelnut, balsam poplar,
alder, blueberry, wildrose, bearberry, sedge, bog birch, and buck bean).
Procedures for optical property measurements are described by Daughtry
et al.(1989). During the measurement, individual leaves remained
attached to the branch that was cut from the plant. Each leaf measured
was inserted into the integrating sphere sample port with the adaxial
(top) surface facing the inside of the sphere. Three measurements
followed: 1) light reflected from the reference for the adaxial surface,
2) light reflected from the adaxial surface, and 3) light transmitted
through the abaxial (bottom) surface. The sample was removed from the
sample port and reinserted so that the abaxial surface faced the inside
of the sphere; the sample was arranged so that the same portion of the
sample as for the adaxial surface was measured. Three additional
measurements followed: 1) light transmitted through the adaxial surface,
2) light reflected from the abaxial surface, and 3) light reflected from
the reference for the abaxial surface. The modified external light
source was used for narrow leaf samples (e.g., wildrose, blueberry, and
bearberry). All other samples were illuminated with the standard
external light source.

For sample type 2, the sample elements were narrow and the tape holding
the needles was not visible in the sample holder (samples included were
jack pine and black spruce needles and twigs).

Prior to 20-Apr-1994:

The fraction of nonintercepted illumination beam was determined using
the painting technique described in Daughtry et al. (1989). This method
allowed only one surface to be measured per sample. Either the standard
or the modified light source was used depending on the sample mount
used.

The sample mount was inserted into the integrating sphere sample holder
with the adaxial needle surfaces facing inside the sphere. Light
reflected from the adaxial needle surface and from the reference with
the sample in place (adaxial reference) was measured. The sample mount
was removed from the sphere. Light reflected from the reference without
a sample and integrating sphere wall (transmitted mode without sample)
was measured. The sample mount was placed back into the integrating
sphere sample holder with the adaxial needle surfaces facing toward the
inside of the sphere. Light transmitted through the abaxial surfaces was
measured. The sample was turned so that the abaxial needle surfaces of
the sample were facing the inside of the sphere. Three additional
measurements followed: 1) light transmitted through the adaxial needle
surfaces, 2) light reflected from the reference with the sample in place
(abaxial reference), and 3) light reflected from the abaxial needle
surfaces.

After the entire suite of measurements was made, the sample mount was
removed from the integrating sphere. The intended measured surface was
painted with Testors (1149) black paint, with care taken not to paint
the other side of the sample element. The sample mount was placed in the
integrating sphere sample holder with the blackened surface facing away
from the sphere. Light transmitted through the blackened sample was
measured.

After 20-Apr-1994:

A modified set of procedures for optical property measurements described
by Daughtry et al. (1989) was used. The sample mount was attached to a
mask with an aperture the size of the illumination light source beam.
This assembly was placed on the light table underneath an image analysis
system\'s camera. The image was captured and the gap area measured by
counting the number of \"whitish\" pixels. The area was ratioed to the
total area of the incident beam (i.e., the area of the mask) to give the
gap fraction (area of nonintercepted illumination beam). The sample was
then placed in the integrating sphere sample holder and the suite of
measurements, described above, was made. The measurement of the
blackened sample was not made.

Prior to 20-Apr-1994:

To calculate the fraction of nonintercepted illumination beam, the
painting technique described in Daughtry et al. (1989) was used. The
standard light source was used for all samples.

Multiple measurements of the transparent tape alone were made of
reflectance and transmittance properties; little variation was found
between pieces of tape. Thus, a sample, constructed of tape only, was
used to characterize the light reflected and transmitted through the
tape for each sample in the suite of measurements described below. The
tape sample was placed in the integrating sphere with the adhesive side
of the tape facing the inside of the sphere. The light reflected from
the tape and the light reflected from the reference with the sample in
place (adhesive side) were measured. The tape sample was turned so that
the adhesive side was facing away from the inside of the sphere. The
light reflected from the reference with the sample in place (nonadhesive
side) and the light transmitted through the tape were measured. The
needle sample mount was placed in the sample holder with the sample
elements facing away from the inside of the sphere. Light transmitted
through the sample was measured. The sample mount was removed from the
sphere. The light transmitted through the sample port without the sample
(i.e., a sphere wall reference) and the light reflected from the
reference (without the sample) were measured. Then, the sample mount was
placed in the sample holder with the sample elements facing away from
the inside of the sphere. Light reflected from the reference with the
sample in place (for transmittance calculation) was measured. Then the
sample mount was placed in the sample holder with the sample elements
facing toward the inside of the sphere. Light reflected from the
reference with the sample in place (for reflectance calculation) and the
light reflected from the sample were measured.

After the entire suite of measurements was made, the sample mount was
removed from the integrating sphere. The intended measured surface was
painted with Testors (1149) black paint, with care taken not to paint
the tape. The sample mount was placed in the integrating sphere sample
holder with the blackened surface facing away from the sphere.
Transmitted radiation through the blackened sample was measured.

After 20-April-1994:

This method allows measurement of only one side of the sample. The image
analysis system was used, in the same manner as type 2, to measure the
fraction of nonintercepted illumination beam. The sample was then placed
in the integrating sphere, and the suite of measurements, as described
above, was made except for the measurement of the blackened sample.

For more details on the LI-COR LI-1800-12 integrating sphere
configuration for each measurement, see Mesarch et al. (1991).

6\. Observations

6.1 Data Notes

None given.

6.2 Field Notes

Needle ages measured in 1993 were 1993 growth, 1992 growth and 1991
growth. Needle and twig ages measured in 1994, unless otherwise noted,
are 1994 growth, 1993 growth, and 1992 growth.

Sampled: 04-Aug-1993

Measured: 04-Aug-1993

Leaf optical properties from aspen near SSA-FEN; 3 trees x 3 branches x
3 replications; both adaxial and abaxial surfaces. First replication was
for a leaf at the top of the branchlet, second replication was for a
leaf in the middle of the branchlet, and third replication was for a
leaf on the lowest part of the branchlet. Branches were selected from
the north side of the trees.

Sampled: 04-Aug-1993

Measured: 05-Aug-1993

Needle optical properties from jack pine near SSA-FEN; 3 trees x 1
branch x 3 ages x 3 replications of adaxial needle surfaces; several
measurements of abaxial needle surface and adaxial twig surface.
Branches from trees 1 and 2 were sunlit, and the branch from tree 3 was
shaded.

Sampled: 06-Aug-1993

Measured: 07-10-Aug-1993

Coordinate measurements of leaf gas exchange and needle optical
properties from black spruce near SSA-FEN. 3 trees x 4 branches x 3 ages
x 3 replications of adaxial needle surface. Tree 1 was sunlit, tree 2
was lightly shaded, and tree 3 was deeply shaded. All trees were about 3
to 3.5 m tall in a grove of trees about 10 m tall. Needles from the
shoots that were measured for photosynthesis rates were not used for
optical property measurements. Instead, needles from a shoot near those
sampled for gas exchange were used.

Sampled: 16-Aug-1993

Measured: 17-18-Aug-1993

Optical properties from jack pine needle and substrate elements at
SSA-YJP. 9 trees x 1 branch x 3 ages x 1 replication of adaxial needle
surface; several measurements of abaxial needle surface and adaxial twig
surface. 9 samples were measured of dead needles, bark, blueberry,
bearberry, and leafy lichen; both adaxial and abaxial surfaces were
measured of all substrate elements except the dead needles.

Sampled: 19-Aug-1993

Measured: 19-Aug-1993

Coordinated measurements of leaf gas exchange and leaf optical
properties on aspen near SSA-FEN (11 trees x 1 branch x 1 replication on
both adaxial and abaxial leaf surfaces). Trees were approximately 2 m
tall. Also leaf optical properties of bog birch (5 plants x 3 color
classes x 1 replication of adaxial and abaxial leaf surface) and buck
bean (9 plants x 1 replication of adaxial and abaxial leaf surface).

Sampled: 20-Aug-1993

Measured: 21-Aug-1993

Coordinated measurements of leaf gas exchange and needle optical
properties on black spruce near SSA-FEN. 5 trees x 1 branch x 3 ages x 1
replication of adaxial needle surface; several measurements of abaxial
needle surface and adaxial twig surface. Needles measured for
photosynthesis rates were not used for optical property measurements;
instead, needles from shoots close to the shoot used for gas exchange
were used. Leaf optical properties of other vegetation in or near the
SSA-FEN (e.g., marsh marigold, cinquefoil and Labrador tea) were
measured (5 plants x 1 replication of adaxial and abaxial leaf surface).

Sampled: 03-Feb-1994

Measured: 13-Feb-1994

Needle optical properties on jack pine collected at SSA-OJP. 7 trees x 1
branch x 3 ages x 3 replications; measurement of both adaxial and
abaxial surfaces. Needles were from the 1993, 1992, and 1991 growth.

Sampled: 07-Feb-1994

Measured: 14-Feb-1994

Needle optical properties from black spruce collected at SSA-OBS. 8
trees x 1 branch x 3 ages x 3 replications; measurement of both adaxial
and abaxial surfaces. Needles were from the 1993, 1992, and 1991 growth.

Sampled: 14-Apr-1994

Measured: 20-21-Apr-1994

Needle optical properties from jack pine collected at SSA-OJP. 1 tree x
3 branches x 3 ages x 3 replications; measurement of both adaxial and
abaxial surfaces. Needles were from the 1993, 1992, and 1991 growth.

Sampled: 15-Apr-1994

Measured: 20-21-Apr-1994

Needle optical properties from black spruce collected at SSA-OBS. 6
trees x 2 branches x 3 ages x 3 replications; measurement of both
adaxial and abaxial surfaces. Needles were from the 1993, 1992, and 1991
growth.

Sampled: 26-May-1994

Measured: 27-29-May-1994

Needle leaf optical properties on jack pine collected at SSA-YJP. 9
trees x 1 branch x 3 ages x 3 replications; measurements of both adaxial
and abaxial surfaces. Trees were located about 150 m east of the hut and
20-50 m north of access road. Branches were from the south side of the
trees and generally in full sunlight at 1230-1600 local time. Branches
were collected 2-4 m from the soil surface. Needles were from the 1993,
1992, and 1991 growth.

Sampled: 29-May-1994

Measured: 29-May-1994

Leaf optical properties from aspen collected at SSA-YA. 3 trees x 3
branches x 3 replications; measurements of both adaxial and abaxial
surfaces. Leaves were from branches sampled from the south side of the
trees and 1.5-2 m from the soil surface.

Sampled: 01-Jun-1994

Measured: 2-4-Jun-1994

Needle optical properties from black spruce collected at SSA-OBS. 3
trees x 3 branches x 3 ages x 3 replications; measurements of mostly
adaxial surfaces. Needles were from the 1993, 1992, and 1991 growth.
Samples were collected from the top of the trees via th canopy access
tower and on the south-facing side of the trees. Branches were sunlit.

Sampled: 04-Jun-1994

Measured: 04-Jun-1994

Needle optical properties from jack pine samples that were coordinated
with shoot gas exchange measurements. Samples were collected at SSA-YJP.
4 trees x 1 branch x 2 ages x 3 replications; measurements of both
adaxial and abaxial surfaces. Needles were from the 1993 and 1992
growth. In addition, reflectance was measured from 1994\'s unexpended
growth (the entire unexpended shoot); 1 replication for each tree.

Sampled: 06-Jun-1994

Measured: 06-Jun-1994

Measurements of leaf optical properties on aspen collected at SSA-OA. 3
trees x 3 branches x 3 replications for the top of the canopy and 1 tree
x 3 branches x 3 replications from the lowest leaf level in the canopy.
Measured adaxial and abaxial surfaces. Sample collection was made from
the canopy access tower.

Sampled: 07-Jun-1994

Measured: 8-9-Jun-1994

Needle optical properties from black spruce collected at SSA-OBS. 3
trees x 3 branches x 3 ages x 3 replications; measurements of mostly
adaxial surfaces. Needles were from the 1993, 1992, and 1991 growth.
Samples were collected from lower in the canopy (approximately 9 m from
the soil surface) via the canopy access tower. Branches from trees 1 and
2 were mostly shaded. Branches from tree 3 were sunlit most of the time.
Measured reflectance properties of black spruce twigs.

Sampled: 07-Jun-1994

Measured: 07-Jun-1994

Leaf optical properties from aspen collected at SSA-YA. 3 trees x 3
branches x 3 replications from sunlit branches at the top of the canopy;
measured adaxial and abaxial surfaces.

Sampled: 10-Jun-1994

Measured: 10-12-Jun-1994

Needle optical properties from jack pine collected at SSA-YJP. 9 trees x
1 branch x 3 ages x 3 replications; measurements of both adaxial and
abaxial surfaces. Trees were located about 150 m east of the hut and
20-50 m south of the access road. Branches were collected near the top
of the south side of trees. Needles were from the 1993 and 1992 growth.
In addition, reflectance was measured from 1994\'s growth (the shoot was
just expanding) for the entire shoot. Measured reflectance for 3
replications of male cones from each tree.

Sampled: 15-Jun-1994

Measured: 15-Jun-1994

Leaf optical properties from aspen collected at SSA-YA. 3 trees x 3
branches x 3 replications for the top of the canopy; measured adaxial
and abaxial surfaces. The optical property system was set up inside the
van because rain prevented \"outdoor\" measurements.

Sampled: 21-Jul-1994

Measured: 23-24-Jul-1994

Needle optical properties from jack pine collected at SSA-YJP. 9 trees x
1 branch x 3 ages x 3 replications; measurements of both adaxial and
abaxial surfaces. Trees were located about 250 m east of the hut and 80
m south of the access road. Branches were collected from the south side
of sunlit trees, 1.5-2 m from the soil surface. Needles from 1994, 1993,
and 1992 growth were measured.

Sampled: 25-Jul-1994

Measured: 26-27-Jul-1994

Needle optical properties from jack pine collected at SSA-YJP. 9 trees x
1 branch x 3 ages x 3 replications; measurements of both adaxial and
abaxial surfaces. Trees were located about 150 m east of the hut and
20-40 m north of the access road. Branches were collected from the south
side of sunlit trees at the top of the canopy. Twig reflectance was
measured. Needles from 1994, 1993, and 1992 growth were measured.

Sampled: 29-Jul-1994

Measured: 29-Jul-1994

Leaf optical properties from aspen collected at SSA-YA. 3 trees x 3
branches x 3 replications from the top of the canopy; measured adaxial
and abaxial surfaces. Branches were sunlit. Leaf optical properties on
understory components (hazelnut, balsam poplar, and alder) collected at
SSA-YA. 9 trees x 1 replication. Samples were shaded within the aspen
canopy.

Sampled: 30-Jul-1994

Measured: 31-Jul-02-Aug-1994

Needle optical properties from black spruce collected at SSA-OBS. 3
trees x 3 branches x 3 ages x 3 replications; mostly adaxial surfaces.
Samples were collected from sunlit branches at the top of the canopy via
the canopy access tower. Needles were from the 1994, 1993, and 1992
growth.

Sampled: 02-Aug-1994

Measured: 02-04-Aug-1994

Needle optical properties from black spruce collected at SSA-OBS. 3
trees x 3 branches x 3 ages x 3 replications; mostly adaxial surfaces.
Samples were collected from shaded branches lower in the canopy
(approximately 9 m from the soil surface) via the canopy access tower.
Needles were from the 1994, 1993, and 1992 growth. Reflectance
properties of black spruce twigs were measured. Optical properties of
understory components were also measured (e.g., wildrose, Labrador tea,
and blueberry); 5 samples of each component.

Sample: 05-Aug-1994

Measured: 05-Aug-1994

Leaf optical properties on species (e.g., bog birch, buck bean, buck
bean with dried, rusty residue {rimpis}, and sedge) at SSA-FEN. 5
samples of each species; adaxial and abaxial surfaces were measured.

Sampled: 04-Sep-1994

Measured: 05-06-Sep-1994

Needle optical properties from black spruce collected at SSA-OBS. 3
trees x 3 branches x 3 ages x 3 replications; mostly adaxial surfaces.
Samples were collected from lower in the canopy (approximately 9 m from
the soil surface) via the canopy access tower. Trees 1 and 3 are sunlit
samples, and tree 2 is shaded. Measurements were not made on tree 3
branch 2. Needles from 1994, 1993, and 1992 growth were measured.

Sampled: 04-Sep-1994

Measured: 04-Sep-1994

Leaf optical properties from aspen collected at SSA-YA. 3 trees x 3
branches x 3 replications from sunlit branches at the top of the canopy;
adaxial and abaxial surfaces were measured.

Sampled: 07-Sep-1994

Measured: 08-11-Sep-1994

Needle optical properties from black spruce collected at SSA-OBS. 3
trees x 3 branches x 3 ages x 3 replications. Samples were collected
from the top of the canopy via the canopy access tower. Reflectance
properties of black spruce twigs were measured. Optical properties of
understory components (e.g., wildrose, Labrador tea, and blueberry); 5
samples of each component.

Sampled: 07-Sep-1994

Measured: 07-Sep-1994

Coordinated measurements of leaf optical properties and gas exchange on
aspen, hazelnut, and balsam poplar collected at SSA-YA. 3 leaf color
classes x 3 replications from the middle of the canopy. The color
classes were leaves that were identified as Strong Yellow Green (5GY 4/4
to 5GY 6/8), Moderate Yellow Green (2.5GY 5/6 to 2.5GY 7/4), and Strong
Yellow (5Y 8/6 to 5Y 8/12).

Sampled: 11-Sep-1994

Measured: 11-13-Sep-1994

Needle optical properties from jack pine collected at SSA-YJP. 9 trees x
1 branch x 3 ages x 3 replications; both adaxial and abaxial surfaces
were measured. Needles were from 1994, 1993, and 1992 growth. Trees were
located about 150 m east of the hut and 20-40 m north of the access
road; branches were collected from the top of the canopy. Twig
reflectance was measured. Understory components (e.g., brown and yellow
jack pine needles, bark, bearberry, and fuzzy-spiked wild rye) were
measured.

Sampled: 14-Sep-1994

Measured: 14-15-Sep-1994

Needle optical properties from jack pine collected at SSA-YJP. 9 trees x
1 branches x 3 ages x 3 replications; both adaxial and abaxial surfaces
were measured. Trees were located about 100 m east of the hut and 20-40
m north of the access road (near the canopy access scaffolding). Sunlit
branches were collected from the south side of the trees approximately
2-3 m from soil surface. Twig reflectance was measured.

7\. Data Description

7.1 Spatial Characteristics

See below.

7.1.1 Spatial Coverage

The measurement sites and associated North American Datum 1983 (NAD83)
coordinates are:

SSA-OBS canopy access tower located at the flux tower site, site id
G8I4T, Lat/Long: 53.98717 N, 105.11779 W, Universal Transverse Mercator
(UTM) Zone 13, N:5,982,100.5 E:492,276.5

SSA-FEN site id F0L9T, Lat/Long: 53.80206 N, 104.61798 W, UTM Zone 13,
N:5,961,566.6 E: 525,159.8

SSA-OA canopy access tower located 100 m up the path to the flux tower
site, site id C3B7T, Lat/Long: 53.62889 N, 106.19779 W, UTM Zone 13,
N:5,942,899.9 E:420,790.5

SSA-YA canopy access tower, site id D0H4T, Lat/Long: 53.65601 N,
105.32314 W, UTM Zone 13, N:5,945,298.9, E:478,644.1

SSA-YJP near the flux tower site, site id F8L6T, Lat/Long: 53.87581 N,
104.64529 W, UTM Zone 13, N:5,969,762.5 E:523,320.2

7.1.2 Spatial Coverage Map.

Not available.

7.1.3 Spatial Resolution

The standard external light source has a spot size 11.4 mm in diameter.
The modified external light source has a spot size restricted to 3.5 mm
x 11 mm. Jack pine needles were longer than the spot size of 11.4 mm,
while the black spruce needles were slightly longer than the 3.5-mm
narrow part of the modified external light source. Broad leaves easily
fit into the 11.4-mm diameter of the standard light source.

7.1.4 Projection

None given.

7.1.5 Grid Description

None given.

7.2 Temporal Characteristics

Aspen, hazelnut, balsam poplar, alder, marsh marigold, cinquefoil,
sedge, buck bean, and bog birch leaves were measured on the same day
that the samples were cut from the plant. Samples of aspen, hazelnut,
and poplar were measured at least once every IFC; the other species were
measured at least once during BOREAS. Substrate elements were measured
up to two days after they were collected. Black spruce and jack pine
samples were measured between 1 and 4 days after they were collected.
Jack pine and black spruce samples were collected two times each IFC.

7.2.1 Temporal Coverage.

Branches were collected from 1530-0023 Greenwich Mean Time (GMT). Leaf,
needle, and twig optical properties measurement times ranged from
1130-0500 GMT. Measurements were not made continuously (IFC-1993:
04-Aug-1993 through 21-Aug-1993; IFC-1 1994: 26-May-1994 through
15-Jun-1994; IFC-2: 21-Jul-1994 through 05-Aug-1994; IFC-3: 04-Sep-1994
through 11-Sep-1994).

The following list gives the date, site, and type of samples collected:

Date Site Species

\-\-\-\-\-\-\-\-\-- \-\-\-\-\-\-- \-\-\-\-\-\-\-\-\--

04-AUG-1993 SSA-FEN Jack Pine

04-AUG-1993 SSA-FEN Aspen

06-AUG-1993 SSA-FEN Black Spruce

16-AUG-1993 SSA-YJP Jack Pine

19-AUG-1993 SSA-FEN Aspen

19-AUG-1993 SSA-FEN Buck Bean

19-AUG-1993 SSA-FEN Bog Birch

20-AUG-1993 SSA-FEN Black Spruce

21-AUG-1993 SSA-FEN Ledum

26-May-1994 SSA-YJP Jack Pine

29-May-1994 SSA-YA Aspen

01-JUN-1994 SSA-OBS Black Spruce

04-JUN-1994 SSA-YJP Jack Pine

06-JUN-1994 SSA-OA Aspen

07-JUN-1994 SSA-OBS Black Spruce

07-JUN-1994 SSA-YA Aspen

10-JUN-1994 SSA-YJP Jack Pine

15-JUN-1994 SSA-YA Aspen

21-JUL-1994 SSA-YJP Jack Pine

25-JUL-1994 SSA-YJP Jack Pine

29-JUL-1994 SSA-YA Aspen

29-JUL-1994 SSA-YA Hazelnut

29-JUL-1994 SSA-YA Alder

29-JUL-1994 SSA-YA Balsam Poplar

30-JUL-1994 SSA-OBS Black Spruce

02-AUG-1994 SSA-OBS Black Spruce

02-AUG-1994 SSA-OBS Ledum

02-AUG-1994 SSA-OBS Wild Rose

02-AUG-1994 SSA-OBS Blueberry

05-AUG-1994 SSA-FEN Bog Birch

05-AUG-1994 SSA-FEN Buck Bean

05-AUG-1994 SSA-FEN Sedge

04-SEP-1994 SSA-OBS Black Spruce

04-SEP-1994 SSA-YA Aspen

07-SEP-1994 SSA-OBS Black Spruce

07-SEP-1994 SSA-OBS Ledum

07-SEP-1994 SSA-OBS Wild Rose

07-SEP-1994 SSA-OBS Blueberry

07-SEP-1994 SSA-YA Aspen

07-SEP-1994 SSA-YA Hazelnut

07-SEP-1994 SSA-OBS Balsam Poplar

08-SEP-1994 SSA-YJP Jack Pine

11-SEP-1994 SSA-YJP Jack Pine

7.2.2 Temporal Coverage Map

None given.

7.2.3 Temporal Resolution

Measurements of sample type 1 required approximately 3 minutes.
Measurements of sample type 2 required a minimum of 7 minutes. The most
time-consuming part of the procedure was creating the sample. The
optimum time interval between sample measurements was a few minutes
during a measurement period.

7.3 Data Characteristics

Data characteristics are defined in the companion data definition file
(te12lod.def).

7.4 Sample Data Record

Sample data format shown in the companion data definition file
(te12lod.def).

8\. Data Organization

8.1 Data Granularity

All of the Leaf Optical Data for SSA Species are contained in one
dataset.

8.2. Data Format

The data files contain numerical and character fields of varying length
separated by commas. The character fields are enclosed in single
apostrophe marks. There are no spaces between the fields. Sample data
records are shown in the companion data definition file (te12lod.def).

9\. Data Manipulations

9.1 Formulae

None given.

9.1.1 Derivation Techniques/Algorithms

For sample type 1: sample fills the integrating sphere sample port:

REFL(I) = \[(R(I) - STR(I)) / (REF(I) - STR(I))\] \* 100 \[1\]

where

REFL = hemispherical reflectance of adaxial or abaxial leaf surface

(percent)

I = channel

R = adaxial or abaxial reflected measurement (counts)

STR = stray light measurement (counts)

REF = adaxial or abaxial reference measurement (counts)

TRAN(I) = \[T(I) / (REF(I)-STR(I))\] \* 100 \[2\]

where

TRAN = hemispherical transmittance adaxial or abaxial leaf surface

(percent)

T = adaxial or abaxial transmitted measurement (counts)

REF = abaxial or adaxial reference measurement (counts)

Measurements of nonintercepted beam fraction for sample types 2 and 3
after 20-Apr-1994: The image analysis system was used to measure the
gaps between the sample elements. The ratio of the total gap area to the
incident beam area was used as a measure of the fractional area of
nonintercepted beam, FRACT.

For sample type 2:

REFL(I) = {\[R(I) - STR(I)\] \* \[1 - FRACT\] /

\[REFR(I) - STR(I)\]} \* 100 \[3\]

where

I = channel

R = adaxial or abaxial reflected measurement (counts)

STR = stray light measurement (counts)

REFL = hemispherical reflectance of surface (percent)

REFR = reference measurement with surface (intended to be calculated)

facing toward the sphere (counts)

FRACT = fractional area of nonintercepted beam

TRAN(I) = {\[T(I) / (REFT(I) - STR(I))\] - \[(W(I) \* FRACT) /

(REF(I) - STR(I))\]} \* \[1.0 / (1.0 - FRACT)\] \* 100 \[4\]

where

TRAN = hemispherical transmittance of surface (percent)

REFT = reference measurement with surface (intended to be calculated)

facing away from sphere (counts)

REF = adaxial or abaxial reference measurement (counts)

W = integrating sphere wall reference measurement (transmitted without a

sample) (counts)

T = transmitted measurement of sample (counts)

For sample type 2 and measurements made before 20-Apr-1994: the
fractional area of nonintercepted beam is calculated from a measurement
of the painted sample.

FRAC1 = TBLACK(ii) / {\[REFT(ii) - STR(ii)\] \* W(ii) /

\[REFN(ii) - STR(ii)\]} \[5\]

where

FRAC1 = first iteration of fraction of beam not intercepted by sample

ii = channel centered at approximately 680 nanometers

TBLACK = transmitted measurement of painted sample (counts)

REFT = reference measurement with surface facing away from sphere
(counts)

W = integrating sphere wall reference measurement (transmitted without a

sample) (counts)

REFN = reference measurement without sample (count)

STR = stray light measurement (counts)

TRAN680 = {\[T(ii) / (REFT(ii) - STR(ii))\] -

\[(W(ii) \* FRAC1) / (REFN(ii) - STR(ii)\]} / (1.0 - FRAC1) \[6\]

where

TRAN680 = transmittance of sample at 680 nanometers

T = transmitted measurement of unpainted sample (counts)

FRACT = {\[T(ii) / (REFT(ii) - STR(ii))\] - TRAN680} /

{\[W(ii) / \[REFN(ii) - STR(ii)\] - TRAN680} \[7\]

where

FRACT = fractional area of nonintercepted beam

For instrument check using the neutral density filters:

TRAND(I) = {\[T(I) / (REF(I) - STR(I))\] \*

\[(X(I) - STR(I)) / W(I)\]} \* 100.0 \[8\]

where

TRAND = transmittance of the neutral density filter (percent)

T = transmitted measurement of unpainted sample (counts)

I = channel

W = integrating sphere wall reference measurement (transmitted without a

sample) (counts)

REF = reference measurement with filter in sample port (counts)

X = reference measurement with nothing in sample port (counts)

STR = stray light measurement (counts)

9.2 Data Processing Sequence

9.2.1 Processing Steps

For sample type 1, where the sample filled the integrating sphere sample
port (e.g., aspen, buck bean, bog birch, bearberry, and lichen).
Equation 1 was used to calculate the hemispherical reflectance for the
adaxial and abaxial surfaces. Equation 2 was used to calculate the
hemispherical transmittance for adaxial and abaxial surfaces. Note that
the transmittance calculations use the reference from the opposite
surface (e.g., adaxial transmittance uses reference with abaxial surface
facing into the sphere).

For sample type 2, where the narrow sample was not completely covering
the sample port, but was long enough to extend across the sample mount
(e.g., jack pine and black spruce), equations 3 and 4 were used to
calculate hemispherical reflectance and transmittance, respectively,
based on the fraction of nonintercepted beam.

For sample type 2, where the narrow sample was not completely covering
the sample port and the date was before 20-Apr-1994, the fraction of the
nonintercepted beam was calculated using the measurement from the
painting technique (e.g., jack pine and black spruce). Equation 5 was
used to make a first estimate of the fraction of the illumination beam
not intercepted by the sample. Measurements from the instrument channel
that was centered around 680 nm (i.e., channel 109 was centered at
678.97 nm and 677.10 nm in 1993 and 1994, respectively) were used,
because minimal transmitted radiation through the sample at this
wavelength was assumed (Daughtry et al., 1989). Equation 5 was used to
calculated the actual transmittance for the channel close to 680 nm,
based on the estimate of the fraction of beam not striking the sample
calculated in Equation 5. The actual fraction of nonintercepted beam was
calculated with Equation 7.

For the neutral density filter test of the integrating sphere and
spectroradiometer, equation 8 was used to calculate the hemispherical
transmittance of the neutral density filter. Each filter was measured
three times. The results were compared to the known transmittances of
the filters.

For all sample measurements:

Each SE590 has a unique centered wavelength associated with each of its
252 channels that varies over time. A cubic spline interpolation was
applied to the 252 channels to standardize the centered wavelength to
every 5 nm from 400 to 1000 nm, so that from wavelength to wavelength
and year to year, comparisons could be made among measurements from
various SE590s used in BOREAS.

The measurements submitted are individual sample measurements or
averaged by replication and/or branch. Individual sample measurements
are listed when a corresponding gas exchange measurement was made.
Average values were submitted for other measurements. Averages are
composed of all replications for a tree/age. For example, black spruce
samples collected on 01-Jun-1994 included 3 trees by 3 branches/tree by
3 ages by 3 replications/age for one height in the canopy. Nine files
would be submitted for this collection, one file for each tree and age
class for this height. All understory and substrate elements were
averaged together per sampling date, unless age or color classification
is stated. Files that include averages also include standard deviations.

9.2.2 Processing Changes

For sample type 2, where the narrow sample was not completely covering
the sample port and the date was before 20-Apr-1994, the fraction of the
nonintercepted beam was calculated using the measurement from the
painting technique (e.g., jack pine and black spruce).

9.3 Calculations

None given.

9.3.1 Special Corrections/Adjustments

None given.

9.3.2 Calculated Variables

None given.

9.4 Graphs and Plots

None given.

10\. Errors

10.1 Sources of Error

Errors can result if the sample thickness does not permit proper sealing
around the sample holder of the integrating sphere (this can be a
problem especially in the midvein area of leaves or with twigs and
bark). Light entering or exiting from the loose seal can result in
erroneous values. If the light source is not maintained in a horizontal
position, the light output can vary, leading to errors as the light
source is placed in different configurations in the suite of
measurements to calculate reflectance and transmittance. Samples of bark
and lichen tended to crack when placed in the integrating sphere sample
holder thus allowing light to pass through the sample; reflectances
could be biased lower and transmittances could be biased higher than if
no cracks were present.

Sample type 2 measurements had a greater chance of error than sample
type 1 measurements, especially in the calculation and measurement of
the fraction of nonintercepted beam. The measurement method requires
that the sample always be placed in the integrating sphere sample holder
in the same orientation relative to the integrating sphere for each
measurement; otherwise, the fraction of nonintercepted illumination beam
will not be representative of the true gap fraction between elements
throughout the suite of measurements. The sample mount was designed to
minimize this error. The lower light intensity of the modified external
light source (compared to the standard light source) and the low
reflectance and transmittance of the samples (particularly in the blue
region of the spectrum; 400 to 500 nm) result in low illumination levels
in the sphere that approach the sensitivity level of the SE590.

Samples created with large gap fractions complicated the transmittance
measurements. Large fractions allowed more nonintercepted light into the
sphere than small gap fractions, dominating the transmitted light
signal.

Variations in the sample transmitted component may be masked by the
nonintercepted light and/or be below the sensitivity of the SE590.

Errors in the calculation of the fraction of the nonintercepted beam
using the image analysis system were due to the variability of the light
intensity of the fluorescent light source, resolution of the solid-state
camera with respect to the individual gap areas to be measured, and the
pixel-counting selection process. These errors resulted in approximately
10 to 30 percent relative error when estimating the fraction. Larger
relative errors tended to occur when samples were created with small
fractions (i.e., 5 to 20 percent). However, the sensitivity of the
optical property calculations to the error in the fraction is minimal at
the small fractions. Reflectance calculations are negligibly affected
across the wavelength range of 400 to 1000 nm. Transmittance
calculations vary 1 to 1.5 percent absolute for small fractions with
relative errors of 10 percent in fraction estimation. Samples made
before 20-Jul-1994 were constructed with a wide range of fractions, 30
to 80 percent, and the relative error in fraction measurement was also
large (i.e., 10 to 30 percent). Optical properties, especially
transmittance, are more sensitive to errors in the gap fraction
estimation when the gap fraction is large than when it is small. A 10
percent relative error in large gap fraction measurement gives a 1 to 5
percent and 5 percent absolute error in reflectance and transmittance
calculations, respectively, across the wavelength range.

The following table lists the range of gap fractions that were
measured/calculated, the extreme relative error of the gap fraction, and
the resulting error in the calculation of optical properties using these
gap

fractions.

Gap Relative Optical Visible Near Infrared

Range Error Measurement Abs . Rel. Abs. Rel.

\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\-\--

1\. Round Aperture

5 to 15 10% Refl \<0.5 \<3 1 2

Trans 1.25 16 1.25 4.6

20% Refl \<0.5 \<3 1.25 2.5

Trans 2 \>20 2 5

30 to 60 10% Refl 1.5 8.5 4.5 8.5

Trans 6.5 \>20 5.5 14.5

20% Refl 2 11.7 7 15.5

Trans 10 \>20 8 20

40 to 80 10% Refl 7.5 \>20 12.5 20

Trans 15 \>20 14 \>20

30% Refl 15 \>20 22 \>20

Trans \>20 \>20 25 \>20

2\. Slitted Aperature

5 to 15 15% Refl \<1 \<6 1.25 2.5

Trans 1.5 20 1.75 5.8

30% Refl 1.5 8 2 4

Trans 4 \>20 2.5 7.7

Where Abs is Absolute and Rel is Relative.

Additional information may be found in the report by Mesarch et al.,
1991.

10.2 Quality Assessment

The integrating sphere/SE590 system response changed little between the
measurement periods as indicated by the transmittance measurements of
neutral density filters. Mean bias errors of known transmittances using
the standard external light source averaged over the Thematic Mapper
(TM) waveband regions were 0.13%, -0.09%, -0.09% and -0.03% (450-520,
520-600, 630-690, and 760-19900 nanometers, respectively). Mean bias
errors of known transmittances using the modified external light source
averaged over the TM waveband regions were 0.13%, -0.09%, -0.13% and
-0.07%.

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

Data were examined for general consistency and clarity.

11\. Notes

None.

11.1 Limitations of the Data

None given.

11.2 Known Problems with the data.

Transmittance measurements for sample type 2 occasionally have negative
values, which resulted from errors in the measurement of the fraction of
nonintercepted illumination beam and the sensitivity of the SE590,
especially in the visible region of the spectrum (400 to 700 nm).

11.3 Usage Guidance

Reflectance measurements for all measurement are usable. Transmittance
measurements for sample type 2 may occasionally contain negative values
and should be used with discretion. Transmittance measurements made
before 20-Jul-1994, especially in the visible region of the spectrum
(400 to 700 nm) may not show the small changes based on canopy location
or light environment (shaded or unshaded), whereas measurements after
20-Jul-1994 may show more nuances of transmittance.

11.4 Other Relevant Information

Acknowledgment of other research staff who assisted in measurements:

Liquang Chen, UNL Graduate Student

Brian P. Lang, UNL Undergraduate Student

12\. Application of the Data Set

This data set can be used to examine the optical properties of boreal
vegetation.

13\. Future Modifications and Plans

None given.

14\. Software

14.1 Software Description

SPSS' software JAVA version 1.4.

14.2 Software Access

None given.

15\. Data Access

15.1 Contact Information

Ms. Beth Nelson

BOREAS Data Manager

NASA GSFC

Greenbelt, MD

\(301\) 286-4005

\(301\) 286-0239 (fax)

Elizabeth.Nelson@gsfc.nasa.gov

15.2 Data Center Identification

See Section 15.1.

15.3 Procedures for Obtaining Data

Users may place requests by telephone, electronic mail, or fax.

15.4 Data Center Status/Plans

The Terrestrial Ecology (TE)-12 Leaf optic data are available from the
Earth Observing System Data and Information System (EOSDIS) Oak Ridge
National Laboratory (ORNL) Distributed Active Archive Center (DAAC). The
BOREAS contact at ORNL is:

ORNL DAAC User Services

Oak Ridge National Laboratory

\(865\) 241-3952

ornldaac@ornl.gov

ornl@eos.nasa.gov

16\. Output Products and Availability

16.1 Tape Products

None.

16.2 Film Products

None.

16.3 Other Products

Tabular American Standard Code for Information Interchange (ASCII)
files.

17\. References

17.1 Platform/Sensor//Instrument/Data Processing Documentation

LI-COR LI-1800-12 Integrating Sphere Instruction Manual. 1983. Pub. No.
8305-0034. LI-COR, inc., Lincoln, NE.

Spectron Engineering, Inc. Operating Manual: SE590 field-portable
data-logging spectroradiometer, Spectron Engineering, Denver, CO 80223.

17.2 Journal Articles and Study Reports

Blad, B.L., E.A. Walter Shea, C.J. Hays, and M.A. Mesarch. 1990.
Calibration of field reference panel and radiometers used in FIFE 1989.
AgMet Progress Report 90-3. Department of Agricultural Meteorology.
University of Nebraska-Lincoln. Lincoln, Nebraska 68583-0728.

Daughtry, C.S.T., L.L. Biehl, and K.J. Ranson. 1989. A new technique to
measure the spectral properties of conifer needles. Remote Sens.
Environ. 27:81-1991.

Mesarch, M. A., E.A. Walter-Shea, B.F. Robinson, J.M. Norman and C.J.
Hays. 1991. Performance evaluation and operation of a field-portable
radiometer for individual leaf optical measurements. AgMet Progress
Report 91-2. Department of Agricultural Meteorology, University of
Nebraska-Lincoln, Lincoln, Nebraska 68583-0728.

Munsell Color Charts for Plant Tissue. 1977. MACBETH Div. of Kollmorgen
Instrument Corp., Baltimore, MD.

Norman, J.M. and P.G. Jarvis. 1974. Photosynthesis in Stika Spruce
\[Picea

Sitchenis (Bong.) Carr.\] III. Measurements of canopy structure and
interception of radiation. J. Appl. Ecol. 11:375-398.

Sellers, P. and F. Hall. 1994. Boreal Ecosystem-Atmosphere Study:
Experiment Plan. Version 1994-3.0, NASA BOREAS Report (EXPLAN 94).

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.

Sellers, P., F. Hall, and K.F. Huemmrich. 1996. Boreal
Ecosystem-Atmosphere Study: 1994 Operations. NASA BOREAS Report (OPS DOC
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. Hall, and K.F. Huemmrich. 1997. Boreal
Ecosystem-Atmosphere Study: 1996 Operations. NASA BOREAS Report (OPS DOC
96).

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, and F.E. Guertin.
1997.

BOREAS in 1997: Experiment overview, scientific results, and future

directions. JGR BOREAS Special Issue, 102 (D24), 28731-28769.

Smith, W.K. and G.A. Carter. 1988. Shoot structural effects on needle
temperatures and photosynthesis in conifers. Amer. J. of Bot.
75:496-500.

Williams, D.L. 1991. A comparison of spectral reflectance properties at
the needle, branch and canopy level for selected conifer species. Remote
Sens. Environ. 35:79-1993.

17.3 Archive/DBMS Usage Documentation

None.

18\. Glossary of Terms

Abaxial: The bottom surface of a leaf or needle. For aspen, buck bean,
bog birch, and substrate element samples, this side was not as bright in
color and had a less glossier sheen than the adaxial surfaces. The
abaxial surface of Labrador tea leaves was heavily pubescent; the
current year\'s growth was white pubescent, and the prior years\' growth
having rust-colored pubescent. For black spruce, this was the surface
with the whitish lines. Jack pine needles were attached to twigs in
paired fascicles and generally had a semicircular cross-sectional shape.
For jack pine needles, the inner semicircular concave, curveed side was
considered to be the abaxial surface.

Absolute (Abs) Error: Percent absolute error.

Adaxial: The top surface of a leaf or needle. For aspen, buck bean, bog
birch, and substrate element samples, this side was typically brighter
in color and had a glossier sheen than the abaxial surfaces. The adaxial
surface of Labrador tea leaves was the least pubescent surface. For
black spruce, this was the surface without the whitish lines. Jack pine
needles were attached to twigs in paired fascicles and generally had a
semicircular cross-sectional shape. The outer semicircular convex,
curved side of the needle was considered the adaxial surface.

Adaxial Transmittance: The light shines on the adaxial surface, goes

through the needle, and then passes into the integrating sphere. The

spectroradiometer then measures the integrated light that is bouncing

around in the sphere.

Adaxial Reflectance: The light shines on the adaxial surface, bounces

off this surface, and then bounces around in the integrating sphere. The

spectroradiometer then measures the integrated light that is bouncing

around in the sphere.

Abaxial Transmittance: The light shines on the abaxial surface, goes

through the needle, and then passes into the integrating sphere. The

spectroradiometer then measures the integrated light that is bouncing

around in the sphere.

Abaxial Reflectance: The light shines on the abaxial surface, bounces

off this surface, and then bounces around in the integrating sphere. The

spectroradiometer then measures the integrated light that is bouncing

around in the sphere.

Channel (ch): One band on the SE590, each having a unique wavelength.

Reflectance (Refl): The light shines on the specified surface and
bounces

off this surface and then bounces around in the integrating sphere; the

spectroradiometer then measures the integrated light that is bouncing

around in the sphere

Relative (Rel) Error: Percent relative error.

Transmittance (Trans): The light shines on the specified surface, goes

through the needle and then passes into the integrating sphere; the

spectroradiometer then measures the integrated light that is bouncing

around in the sphere.

19\. List of Acronyms

ASCII - American Standard Code for Inforamtion Interchange

BOREAS - BOReas Ecosystem-Atmosphere Study

BORIS - BOREAS Information System

DAAC - Distributed Active Archive Center

EOS - Earth Observing System

EOSDIS - EOS Data and Information System

FEN - Nipawin Fen site

FFC-T - Focused Field Campaign/Thaw 1994

FFC-W - Focused Field Campaign/Winter 1994

GMT - Greenwich Mean Time

GSFC - Goddard Space Flight Center

IFC - Intensive Field Campaign

NAD - North American Datum of 1983

NASA - National Aeronautics and Space Administration

NSA - Northern Study Area

OA - Old Aspen

OBS - Old Black Spruce

OJP - Old Jack Pine

ORNL - Oak Ridge National Laboratory

PANP - Prince Albert National Park

PAR - Photosynthetically Active Radiation

SSA - Southern Study Area

Stdev - Standard Deviation

TE - Terrestrial Ecology

TM - Thematic Mapper

UNL - University of Nebraska - Lincoln

URL - Uniform Resource Locator

UTM - Universal Transverse Mercator

YA - Young Aspen

YJP - Young Jack Pine

20\. Document Information

20.1 Document Revision Date

Written: 30-Sept-1996

Last Updated: 14-Sep-1998

20.2 Document Review Date(s)

BORIS Review: 30-Apr-1997

Science Review: 27-Jul-1998

20.3 Document ID

20.4 Citation

Please acknowledge the efforts of E.A. Walter-Shea, M.A. Mesarch, and L.
Chen at the University of Nebraska-Lincoln

20.5 Document Curator

20.6 Document URL

[Keywords]{.underline}

Reflectance

Transmittance

Optical Properties

Integrating Sphere