BOREAS TGB-05 CO2, CH4, and CO Chamber Flux Data over the NSA

Summary

The BOREAS TGB-05 team collected a variety of trace gas concentration
and flux measurements at several NSA sites. This data set contains
carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO) chamber
flux measurements conducted in 1994 at upland forest sites that
experienced stand-replacement fires. These measurements were acquired to
understand the impact of fires on soil biogeochemistry and related
changes in trace gas exchange in boreal forest soils. Relevant ancillary
data, including data concerning the soil temperature, solar irradiance,
and information from nearby unburned control sites, are included to
provide a basis for modeling the regional impacts of fire and climate
changes on trace gas biogeochemistry. The data are provided 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

1.1 Data Set Identification

BOREAS TGB-05 CO2, CH4, and CO Chamber Flux Data over the NSA

1.2 Data Set Introduction

These measurements are required to understand the impact of fires on
soil biogeochemistry and related changes in trace gas exchange in boreal
forest soils. Relevant ancillary data, including data concerning the
soil temperature and solar irradiance, are included to provide a basis
for modeling the regional impacts of fire and climate changes on trace
gas biogeochemistry.

1.3 Objective/Purpose

The objective of this study is to examine the effects of fire on
soil-atmosphere fluxes of trace carbon gases (CO2, CH4, CO) in upland
black spruce and jack pine ecosystems located within the BOReal
Ecosystem-Atmosphere Study (BOREAS) Northern Study Area (NSA) near
Thompson, Manitoba.

1.4 Summary of Parameters

This data set contains measurements of ambient carbon dioxide (CO2),
methane CH4 and CO concentrations; CO2, CH4, and CO fluxes; ambient and
soil temperatures; and solar irradiance.

1.5 Discussion

The soil-atmosphere exchange of CO2 is an important component of the
carbon budget of the boreal forest biome. Soil-atmosphere exchange of
CH4 and CO in the boreal biome has major effects on the atmospheric
content of these radiatively and chemically important trace gases.
Closed chamber techniques with gas chromatography were used to determine
the soil surface flux of CO2, CH4, and CO at five BOREAS auxiliary sites
in the NSA that were exposed to intense stand-replacement fires during
the 7-year period prior to 1994. Flux data were also obtained at nearby
control sites. Relevant ancillary data were simultaneously obtained at
the sites. The experiments were conducted from the beginning of June
through the end of August 1995.

The results from this study indicate that upland soils in burned boreal
forests are generally net sources of both CO2 and CO, but net sinks of
atmospheric CH4. Soil temperatures in these burned sites were generally
higher than those observed in nearby unburned controls. Soil respiration
includes both root respiration and decomposition of soil organic matter
(SOM). Despite the loss of root respiration in the burn sites, soil
respiration was nearly the same in the burn sites as in unburned
controls. This indicates that enhancement of SOM decomposition by the
warming of the soil offset the reduction in root respiration. In sites
exposed to the most intense fires, however, where surface organic matter
was considerably reduced and converted to charcoal by fire, soil
respiration was significantly reduced compared to other sites that were
investigated. CH4 sinks were generally greater in the well-drained jack
pine stands than in black spruce stands. CO fluxes are affected by
thermal and photochemical production at the soil surface and by
microbial consumption deeper in the soil. Thus, CO fluxes in the open
burn sites were positive during daylight, whereas the fluxes were
negative in the unburned forest soils.

1.6 Related Data Sets

BOREAS TGB-01 Soil CH4 and CO2 Profile Data over NSA Tower Sites

BOREAS TGB-01 CH4 and CO2 Chamber Flux Data from NSA Tower Sites

BOREAS TGB-01 CH4 Concentration and Flux Data from NSA Tower Sites

BOREAS TGB-01 SF6 Chamber Flux Data over NSA Jack Pine Sites

BOREAS TGB-03 CO2 and CH4 Chamber Flux Data over the NSA

2\. Investigator(s)

2.1 Investigator(s) Name and Title

Dr. Richard G. Zepp and Dr. Roger A. Burke

U.S. EPA, Athens, GA

2.2 Title of Investigation

Trace Gas Exchange in the Boreal Forest Biome: Effects of Fire and
Beaver Activity

2.3 Contact Information

Contact 1

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

Dr. Richard G. Zepp

U.S. Environmental Protection Agency

Athens, GA

\(706\) 355-8117

zepp.richard@epamail.epa.gov

Contact 2

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

Sara Golightley

Raytheon STX Corporation

NASA Goddard Space Flight Center

Greenbelt, MD

\(301\) 286-2624

Sara.Golightly@gsfc.nasa.gov

3\. Theory of Measurements

The CO2, CH4, and CO fluxes at the surface of the soil are important
components of the carbon budget of the boreal forest. Stand-replacement
fires may affect the soil-surface fluxes of these gases. Fire removes
the canopy and part of the moss, lichen, and shrub cover, thus altering
soil temperature, moisture, and nutrient composition. Models of trace
gas biogeochemistry in the boreal forest, such as CENTURY, require field
measurements of these fluxes in order to calibrate the models and test
their predicted fluxes. In order to understand and quantify the carbon
gas exchange in these systems, it is necessary to measure their exchange
under a variety of conditions in unburned plots and burned plots of
various postburn ages.

In particular, CO exchange from the forest ecosystem floor is a poorly
understood process that may exhibit a significant effect on the ambient
CO levels. The forest floor may act as both a source and sink for CO.
Sink activity is believed to be the result of consumption of CO by
microbial activity, while production is primarily the result of thermal
and photochemical decomposition of living and dead organic matter. The
net exchange from the forest floor will therefore be determined by the
relative source and sink strengths of these processes. Some parameters
that are believed to be important in CO exchange are temperature,
moisture content, soil nutrient levels, SOM content, and light
intensity.

4\. Equipment

4.1 Sensor/Instrument Description

CH4 and CO2 were measured using a Karl Gas Chromatograph (GC) equipped
with flame-ionization detector (FID) (for CH4) and thermal conductivity
detector (TCD) (for CO2). CO was measured using a Trace Analytical
(Menlo Park, CA) RGA-3 GC. This instrument isolates CO, and reacts with
HgO, producing Hg vapor. The Hg vapor is detected by atomic absorbance.
Samples are injected through an injection loop (0.5 or 1mL).

Aluminum chamber bases (0.215-m inner diameter \[i.d.\]) were used for
isolating a section of the forest floor. The chambers were anchored with
three or four spikes that were 0.20 m in length. The chambers were also
equipped with a cylindrical skirt to prevent lateral diffusion of gases.
Three skirt sizes were used depending on the ecosystem type: 5 cm, 10
cm, and 20 cm. The opening of the base had a trough filled with water to
provide support and seal the chamber top.

Light measurements were made with an International Light IL1700
radiometer using probes for various light regions (SED 623 for visible,
SED 240 for ultraviolet \[UV\]-A, and SED 033 for UV-B).

Soil temperature was measured with a portable temperature probe
(Cole-Palmer thermistor thermometer L-08110-20).

Soil water content was measured using a 1502B Time Domain Reflectometer
(TDR) \[Topp et al., 1980\].

4.1.1 Collection Environment

Measurements were made at open sites that had experienced
stand-replacement fires within the prior 7 years or at nearby shaded
control forest sites that had not burned for at least 70 years. The soil
temperatures and solar irradiance were typically much higher at the
burned sites than at the control sites. Data were collected under a
variety of ambient temperatures ranging from near 0 degrees C to near 28
degrees C.

4.1.2 Source/Platform

All measurements were made on the ground

4.1.3 Source/Platform Mission Objectives

The mission objective was to measure soil surface CO2, CH4, and CO
fluxes and relevant ancillary data in fire scars and nearby controls.

4.1.4 Key Variables

CO2, CH4, and CO flux; soil temperature; soil moisture content; and
light intensity (total, UV-A, and UV-B).

4.1.5 Principles of Operation

The chamber assays for CO, CO2, and CH4 followed the methods established
by Hutchinson and Livingston \[1993\]. Analysis of CH4 \[Crill, 1991\]
was conducted with 0.5% precision.

4.1.6 Sensor/Instrument Measurement Geometry

Not applicable.

4.1.7 Manufacturer of Sensor/Instrument

RGA-3 Chromatograph

Trace Analytical

3517-A Edison Way

Menlo Park, CA 94025

IL-1700 Radiometer

International Light, Inc.

17 Graf Road

Newburyport, MA 01950

Temperature Probe

Cole-Palmer Instrument Company

7425 North Oak Park Avenue

Niles, IL 60714

TDR

Tektronix, Inc.

Beaverton, OR

4.2 Calibration

4.2.1 Specifications

Instruments were configured and maintained according to manufacturers\'
specifications noted in the instruction manuals and were calibrated
routinely according to standards.

4.2.1.1 Tolerance

The precision of fluxes, for the trace gas measurements, computed from
three replicates, is expected to be 15% for CO2 and CH4, and 5-10% for
CO. The precision is judged by the standard deviation of the three
measurements.

4.2.2 Frequency of Calibration

Calibration was performed immediately before measuring each day\'s
samples. Correlation coefficients of 0.99 or better were achieved in all
cases. A secondary standard of near atmospheric CO2, CH4, or CO
concentration was injected periodically during analysis to ensure that
no instrumental drift occurred.

4.2.3 Other Calibration Information

CH4 and CO2 concentrations were calculated by comparing sample peak
areas obtained with a Shimadzu CR501 dual channel integrator to those
resulting from repeated analysis of two CH4 standards and two CO2
standards. The CH4 standards contained 0.90-ppm and 2.05-ppm CH4, and
the CO2 standards contained 356.1-ppm and 397.4-ppm CO2. The standard
gases were supplied by the BOREAS project and calibrated by the
Atmospheric Environment Service (AES) of Canada. Based on 10 to 15 daily
measurements of these standards, the precision of analysis (standard
deviation divided by the mean value expressed in percentage) was 0.7 ±
0.3% for CH4 and 1.7 ± 0.4% for CO2. For CO calibration, a standard
curve was generated each day by injecting calibrated volumes of a 9.5 ±
0.14-ppm CO primary standard (National Institute of Standards and
Technology, Gaithersburg, MD).

5\. Data Acquisition Methods

A static chamber technique \[such as that described by Whalen and
Reeburgh, 1988\] was used to estimate soil/atmosphere CH4 and CO2
exchange. The chamber consists of a permanently deployed circular
aluminum collar, with a water seal and skirt, and an opaque lid. The
collars were \~10, 25, or 30 cm deep in areas with significant moss,
lichen, or burned vegetation cover, and \~5 cm deep in areas in which
the vegetation had burned to the mineral layer. The lid is constructed
of aluminum and is equipped with a septum for syringe sampling and a
small hole to equalize pressure. The total enclosed area is 0.036 m2,
and the enclosed volume is about 8.7 liters.

CH4 and CO2 flux samples were collected at 5-minute intervals over the
course of 20 minutes in 60-mL polypropylene syringes with siliconized
polypropylene plungers and nylon three-way stopcocks. Syringes were
stored in the dark at ambient temperature until analysis. Concentration
determinations were made using a Carle AGC GC equipped with a TCD and a
FID. Gas samples were introduced to the GC via a 10-port gas sampling
valve plumbed for the simultaneous filling of two sample loops and then
injection into two columns. Separation of CH4 and CO2 was accomplished
with 1/8-inch outer diameter (o.d.) stainless steel Hayesep-D (3 m for
the FID side and 2 m for the TCD side) analytical columns.

Soil-atmosphere CO exchange was measured using transparent, static soil
chambers. These chambers consisted of two parts: a semipermanent base
installed into the ground and a removable glass cover that isolated the
atmosphere immediately above the base. The aluminum chamber bases
consisted of an open-ended, 0.215-m i.d. cylinder (the skirt). The
bottom edge of the skirt was beveled to aid insertion into the soil.
Skirt lengths were either 0.5 or 0.10 m, depending upon the thickness of
the organic layer above the mineral soil. A concentric trough (\~30 cm
i.d. and 4 cm deep) was welded to the top of the chamber. This trough,
when filled with water, provided an airtight seal with the top. Three or
four 0.5-cm-o.d. x 10-cm-long aluminum spikes were attached
symmetrically around the circumference of the skirt to provide a secure
installation. The glass chamber tops were Kimax™ (Kimble, Vineland, NJ)
borosilicate jars (25 cm deep, \~24 cm i.d., volume \~12 liters). These
jars were transparent to visible (400-700 nm) and UV-A (315-400 nm)
light, but filtered out a part of UV-B (280-315 nm) radiation. Two
1/4-inch holes were drilled in the side of each glass jar with a
90-degree radial displacement and \~15 cm vertical displacement between
each hole. These holes were used as sampling and vent ports. The holes
were plugged with small corks, and needles were inserted through the
corks. The vent consisted of a 1inch-long, 22-gauge needle, and the
sampling port consisted of a 4- to 6-inch-long, 18-gauge needle. Both
needles were left open to the atmosphere during sampling, thereby
preventing pressure differentials during experiments.

Soil-atmosphere CO exchange was measured in the following manner. First,
the trough of the chamber base was filled with enough water to ensure an
airtight seal with the chamber top. Then, the top was quickly but gently
placed in the trough and a gas sample of \~20 mL was removed from the
chamber. Additional samples were collected (usually at 7-minute
intervals) for a total of at least four samples. For each sample, the
syringe was connected to the sampling needle and pumped three times to
ensure a well-mixed chamber. Approximately 20 mL of sample was
collected, and the syringe stopcock was closed. The back of the syringe
barrel was sealed with a minimum amount of distilled water and stored in
a plastic ziplock bag on ice until analysis. The all-glass syringes
(Popper & Sons, New Hyde Park, NY) were fitted with gas-tight Teflon™
stopcocks (Alltech Associates, Deerfield, IL) and encased in black
heat-shrink tubing to keep their contents dark. Sampling was conducted
between the hours of 1000 and 1500 local time with the exception of two
diurnal studies.

Air and soil temperatures (at a depth of 10 cm for CO2 and CH4; 1.0 cm
for CO) were measured with a thermocouple probe. Volumetric soil
moisture content was measured with a TDR as described by Topp et al.
\[1984\]. Total solar irradiance was measured during the CO flux
measurements with the light probe placed close to the environmental
chamber.

6\. Observations

6.1 Data Notes

None given.

6.2 Field Notes

Date Location Activity

July 19 Arrive Thompson

July 20 Lab Set up laboratory

July 21 Gillam Road: 94GR, CGR CH4, CO2, CO fluxes

July 22 Gillam Road: 92GR, 87GR CH4, CO2, CO fluxes

July 23 Leaf Rapids Road: 89JP, CJP CH4, CO2, CO fluxes

July 24 Leaf Rapids Road: 89FR, CFR CH4, CO2, CO fluxes

July 25 Gillam Road: 94GR CH4, CO2, CO fluxes; process studies

July 26 Gillam Road: 94GR, 87GR CH4, CO2, CO fluxes

July 27 Gillam Road: CGR, 92GR CH4, CO2, CO fluxes

July 28 Gillam Road: CGR, 92GR CH4, CO2, CO fluxes; process studies

July 29 Tower Beaver Pond CO flux from pond

July 30 Off

July 31 Off

Aug 1 Gillam Road: 94GR, 92GR CH4, CO2, CO fluxes

Aug 2 Gillam Road: CGR, 87GR CH4, CO2, CO fluxes

Aug 3 Leaf Rapids Rd: 89JP, CJP CH4, CO2, CO fluxes

Aug 4 Gillam Road: 92GR CH4, CO2, CO fluxes; diurnal

Aug 5 Gillam Road: 92GR CH4, CO2, CO fluxes; diurnal continued

Aug 6 Gillam Road: CGR, 87GR CH4, CO2, CO fluxes

Aug 7 Gillam Road: 94GR, 92GR CH4, CO2, CO fluxes

Aug 8 Lab Shut down equipment; ship soil samples

Aug 14 Arrive Thompson

Aug 15 Lab Set up lab

Aug 16 Gillam Road: CGR, 94GR CH4, CO2, CO fluxes

94GR #6 dug up by animal;. re-install in another location about 10 ft
toward Thompson

Aug 17 Gillam Road: 92GR, 87GR CH4, CO2, CO fluxes

Aug 18 Gillam Road: CGR CH4, CO2, CO fluxes; diurnal

Aug 19 Gillam Road: CGR CH4, CO2, CO fluxes; diurnal continued

Aug 20 Off

Aug 21 Leaf Rapids Road: 89FR, CFR CH4, CO2, CO fluxes

Aug 22 Leaf Rapids Road: 89JP, CJP CH4, CO2, CO fluxes

Four chamber bases missing from 89 Jack Pine site - presumed stolen;
remove remaining bases to prevent additional theft and remove some
chambers from CJP site for placement in new control site on Gillam Road

Aug 23 Gillam Road: CGR, 92GR CH4, CO2, CO fluxes

Aug 24 Gillam Road: 87GR, 94GR CH4, CO2, CO fluxes

Aug 25 Gillam Road: NGRC, CGR, 87GR CH4, CO2, CO fluxes; SF6 at 87GR

Place three chamber bases in New Gillam Road Control (two medium skirt,
one deep skirt)

Aug 26 Gillam Road: CGR, 92GR, 87GR Simul. rain event at CGR, 92GR,
87GR,

94GR, NCGR 94GR; CH4, CO2, CO fluxes at NCGR

Aug 27 Off

Aug 28 Gillam Road: CGR, 92GR CH4, CO2, CO fluxes

Aug 29 Gillam Road: 87GR, 94GR CH4, CO2, CO fluxes

Aug 30 Gillam Road: 92GR, 94GR, 87GR SF6 diffusion studies

Aug 31 Lab; Leaf Rapids Road: 89FR, CFR SF6 analysis; SF6 diffusion and
CH4/CO2 at 89FR and CFR

Sept 1 Gillam Road: 92GR, 94GR SF6 diffusion studies

Sept 2 Lab Pack and ship equipment

Sept 2 Leave Thompson

7\. Data Description

7.1 Spatial Characteristics

7.1.1 Spatial Coverage

Measurements were performed on upland black spruce (Picea mariana) and
jack pine (Pinus banksiana) forest sites in the vicinity of the BOREAS
NSA, which is located near Thompson, Manitoba (55¤91\' N, 98¤42\' W).
Four black spruce sites, three burned and one control, were selected
about 100 km northeast of Thompson, Manitoba. The sites were located at
56¤09\' N, 96¤44\' W; 56¤08\' N, 96¤42\' W. All four black spruce sites,
which were located within 5 km of each other, were exposed to very
similar climatic conditions. The jack pine burn site was located in a
large burn site (115,643 ha; summer 1989) on Hwy 391 near Leaf Rapids,
Manitoba, 140 km west-northwest of Thompson, Manitoba. A jack pine stand
located 133 km west-northwest of Thompson, unburned for at least 80
years, served as the control for the jack pine burn site.

At each site, the environmental chambers were used to measure fluxes
within an area that was approximately 10,000 m2.

7.1.2 Spatial Coverage Map

A map showing site locations is included.

7.1.3 Spatial Resolution

The environmental chambers used to measure soil fluxes of CO2, CO, and
CH4 covered an area about 0.036 m2. Flux measurements for CO2, CO, and
CH4 were at six locations within the site.

7.1.4 Projection

Not applicable.

7.1.5 Grid Description

Not applicable.

7.2 Temporal Characteristics

7.2.1 Temporal Coverage

The environmental chambers were used to measure soil surface fluxes
between June and September 1994. Data were obtained during Intensive
Field Campaign (IFC)-1, IFC-2, August 1994, and the first week of IFC-3.

7.2.2 Temporal Coverage Map

Not available.

7.2.3 Temporal Resolution

Individual flux measurements generally were made over a period of 20 to
30 minutes. Flux experiments were routinely conducted between the hours
of 10:00 and 1600. local time with selected diurnal studies during
August 1994 conducted throughout the day and night.

The flux and ancillary data at a given black spruce site were obtained
with a sampling frequency of 2-3 days during the periods noted in
Section 7.2.1. Data at the jack pine sites were obtained on a weekly
basis.

7.3 Data Characteristics

Data characteristics are defined in the companion data definition file
(tgb5cflx.def).

7.4 Sample Data Record

Sample data format shown in the companion data definition file
(tgb5cflx.def).

8\. Data Organization

8.1 Data Granularity

All of the CO2, CH4 and CO Chamber Flux Data over the NSA are contained
in one dataset.

8.2 Data Format(s)

The data files contain numerical and character fields of varying length
separated by commas. The character fields are enclosed with a single
apostrophe marks. There are no spaces between the fields. Sample data
records are shown in the companion data definition file (tgb5cflx.def).

9\. Data Manipulations

9.1 Formulae

9.1.1 Derivation Techniques and Algorithms

None.

9.2 Data Processing Sequence

9.2.1 Processing Steps

Gas samples were collected from the environmental chambers at the field
sites, transferred to the laboratory, and analyzed by gas
chromatography. The fluxes were then calculated from measured
concentrations of the gases vs. time.

9.2.2 Processing Changes

None given.

9.3 Calculations

9.3.1 Special Corrections/Adjustments

For each chamber experiment, the concentration of CO within the chamber
was plotted as a function of time after sealing the chamber top over the
base. These plots showed three different patterns: (1) linear changes
with time, (2) first-order decay with time, and (3) initial linear
increase followed by a diminished rate of increase, often yielding a
steady state. Concentration vs. time plots were initially plotted to
determine the curve shape, and the data analysis was determined based on
curve shape. Data were analyzed by performing linear regression (slope =
CO exchange rate), by performing log-linear regression (slope =
first-order rate constant), or by determining the initial slope.

9.3.2 Calculated Variables

Fluxes of CO2 and CH4 were calculated by linear regression of the
measured concentrations of samples (typically five) collected during
each chamber deployment. CO fluxes were calculated as described in
Section 9.3.1.

9.4 Graphs and Plots

Data were plotted using Lotus Freelance, Lotus 123, and Quattro Pro.

10\. Errors

10.1 Sources of Error

A few flux measurements were rejected because of various problems such
as loss of one or more time points, contaminated or leaky syringes, GC
problems, or disturbance of the site during sampling. These problems
usually became apparent when either: (1) the initial concentration was
not close to the ambient concentration, or (2) the correlation
coefficient of the linear regression was not significant at the 90%
confidence level (r2 = 0.810 for n = 4; r2 = 0.648 for n = 5).

10.2 Quality Assessment

Based on the actual performance of the flux measurement system during
this study, the minimum detectable flux of CH4 is estimated to be about
0.3 mg CH4-C m-2 d-1, and the minimum detectable flux of CO2 to be 0.1 g
CO2-C m-2 d-1.

10.2.1 Data Validation by Source

Calibrations and instrumentation ranges were checked, and data were
checked for values that were not in expected ranges.

10.2.2 Confidence Level/Accuracy Judgment

For all of the CO2 and CH4 data analyzed with regressions, data sets
were rejected if the correlation coefficient of the linear regression
was not significant at the 90% confidence level (r2 = 0.810 for n = 4;
r2 = 0.648 for n = 5). For CO measurements that exhibited decreasing CO
concentrations vs. time, the data sets were rejected if the correlation
coefficient of the linear regression of log concentration vs. time was
not significant at the 90% confidence level.

10.2.3 Measurement Error for Parameters

Typically, replicate measurements of the same gas sample are within 10%
RSD for CO2, CH4, and CO.

10.2.4 Additional Quality Assessments

Multiple comparison procedures were performed with the software package
SigmaStat (Jandel Scientific, San Rafael, CA) to test for statistically
significant differences in gas fluxes and volumetric water content among
sets of samples grouped by site or by date within a given site. Each
data group was tested for normality (Kolmogorov-Smirnov test) and equal
variance (Levene median test) with the SigmaStat package. For
comparisons of data groups with normal distributions and equal
variances, a One Way Analysis of Variance (ANOVA) was performed to test
for differences in mean values of the different groups. If significant
differences in the means were found, then a Student-Newman-Keuls (SNK)
All Pairwise Multiple Comparisons Procedure was performed to identify
specific differences between groups. For comparisons of data groups in
which normality and/or equal variance conditions were not met, a
Kruskal-Wallis ANOVA on ranks was performed. If the differences in the
median values among these groups were found to be significant, then
specific differences between groups were tested for by the DunnÌs Method
of All Pairwise Multiple Comparisons. Mean ranks were calculated from
the results of the ranking procedures associated with the nonparametric
tests and are presented to indicate trends in the various parameters.
Probability and significance levels were set to 0.05 in the SigmaStat
package unless otherwise specified. Simple and multiple linear
regression procedures were also performed with the SigmaStat package.
Zar \[1984\] and Glanz and Slinker \[1990\] give details of the
statistical tests performed.

10.2.5 Data Verification by Data Center

Data were examined for general consistency and clarity.

11\. Notes

11.1 Limitations of the Data

There are no known limitations. However, the user should be aware that
there are few other data sets available on soil trace gas fluxes in
sites that have been recently burned. Therefore, there is no way at this
point to judge the representativeness of this data set.

11.2 Known Problems with the Data

None.

11.3 Usage Guidance

None given.

11.4 Other Relevant Information

The procedures and data obtained in this study are monitored by several
mechanisms:

a\) Formal methods of comparisons. Several comparisons have been made
under field and laboratory conditions that have substantiated that the
instruments used in this study provide reliable measurements of trace
gases.

b\) Informal comparisons among investigators. Comparisons of the data
obtained in this study at unburned control sites with flux data obtained
using environmental chambers or towers at other BOREAS NSA sites
indicate that these fluxes are in the same range as those observed
elsewhere in this region. This favorable comparison suggests that these
results are representative of this region.

c\) Review in the scientific literature. These and other BOREAS results
will be published in a timely fashion in a Special Issue of the Journal
of Geophysical Research so that they will be available to the
international scientific community. In these publications, the methods
must be justified to peer referees. These justifications are based on
other published methods and tests, which are described in previous
papers.

12\. Application of the Data Set

None given.

13\. Future Modifications and Plans

None.

14\. Software

14.1 Software Description

These results are being used to improve the CENTURY soils model so that
it can be used to evaluate carbon storage and trace gas fluxes in boreal
forest soils.

14.2 Software Access

The SigmaStat, Lotus, and other commercial software packages are
available from their specific commercial developers.

The CENTURY software will be available from Dr. Dennis Ojima and Dr.
William Parton, NREL, Colorado State University, Ft. Collins, CO. The
data also likely will be used to improve and test other models that
simulate the biosphere-atmosphere exchange of trace gases.

15\. Data Access

15.1 Contact Information

Ms. Beth Nelson

BOREAS Data Manager

NASA GSFC

Greenbelt, MD

\(301\) 286-4005

\(301\) 286-0239 (fax)

beth@ltpmail.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

These 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

None.

17.2 Journal Articles and Study Reports

Burke, R.A., R.G. Zepp, M.A. Tarr, W.L. Miller, and B.J. Stocks. 1998.
Effect of fire on soil-atmosphere exchange of methane and carbon dioxide
in a Canadian Boreal Forest. J.Geophys. Res. (accepted).

Crill, P.M. 1991. Seasonal patterns of methane uptake and carbon dioxide
release by a temperate woodland soil. Global Biogeochemical Cycles 5:
319-334.

Glanz, S.A. and B.K. Slinker. 1990. Primer of Applied Regression and
Analysis of Variance. McGraw-Hill, New York, 777 pp.

Hutchinson, G.L., and G.P. Livingston. 1993. Use of chamber systems to
measure trace gas fluxes, in Agricultural Ecosystem Effects on Trace
Gases and Global Climate Change. ASA Special Publication No. 55.
American Society of Agronomy, Madison, WI, pp. 63-78.

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

Sellers, P.and F. Hall. 1997. BOREAS Overview Paper. JGR Special Issue
(in press). Whalen, S.C., and W.S. Reeburgh. 1988. A methane flux time
series for tundra environments. Global Biogeochem. Cycles, 2, 399-409.

Sellers, P., F. Hall, 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.

Topp, G.C., J.L. Davis, W.G. Bailey, and W.D. Zebchuk. 1984. The
measurement of soil water content using a portable TDR hand probe. Can.
J. Soil Sci., 313-321.

Zar, J.H. Biostatistical Analysis, 2nd Ed. Prentice-Hall, Englewood
Cliffs, NJ, 718 pp.

Zepp, R.G., W.L. Miller, M.A. Tarr, R.A. Burke, and B.J. Stocks. 1998.
Soil-atmosphere fluxes of carbon monoxide during early stages of
post-fire succession in upland Canadian boreal forests. J. Geophys. Res.
(accepted).

17.3 Archive/DBMS Usage Documentation

None.

18\. Glossary of Terms

None given.

19\. List of Acronyms

AES - Atmospheric Environment Services

ANOVA - One Way Analysis of Variance

ASCII - American Standard Code for Information Interchange

BOREAS - BOReal Ecosystem-Atmosphere Study

BORIS - BOREAS Information System

CGR - Certified by Group

CPI - Checked by PI

CPI-??? - CPI but questionable

DAAC - Distributed Active Archive Center

EOS - Earth Observing System

EOSDIS - EOS Data and Information System

FID - Flame Ionization Detector

GC - Gas Chromatograph

GMT - Greenwich Mean Time

GSFC - Goddard Space Flight Center

IFC - Intensive Field Campaign

NASA - National Aeronautics and Space Administration

URL - Uniform Resource Locator

PANP - Prince Albert Natinoal Park

PI - Principal Investigator

PRE - Preliminary

ORNL - Oak Ridge National Laboratory

SNK - Student-Newman-Keuls

SOM - Soil Organic Matter

SSA - Southern Study Area

TCD - Thermal conductivity Detector

TDR - Time Domin Reflectometer

TGB - Trace Gas Biogeochemistry

UV - Ultraviolet

20\. Document Information

20.1 Document Revision Date

Written: 04-Jun-1997

Last updated: 20-Jul-1998

20.2 Document Review Date(s)

BORIS Review: 06-Oct-1997

Science Review:

20.3 Document ID

20.4 Citation

20.5 Document Curator

20.6 Document URL

Keywords

Methane

Carbon Dioxide

Carbon Monoxide