NASA/TMm2000-209891, Vol. 191

Technical Report Series on the

Boreal Ecosystem-Atmosphere Study (BOREAS)

Forrest G. Hall and Karl Huemmrich, Editors

Volume 191

BOREAS TF-1 SSA-OA

Weekly Tower CH 4 and N20 Flux

George Thurtell and Grant Edwards, University of Guelph, Ontario

Isobel Simpson, University of California, Irvine

National Aeronautics and

Space Administration

Goddard Space Flight Center

Greenbelt, Maryland 20771

October 2000

https://ntrs.nasa.gov/search.jsp?R=20010022498 2018-05-14T18:55:59+00:00Z
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NASA/TMm2000-209891, Vol. 191

Technical Report Series on the

Boreal Ecosystem-Atmosphere Study (BOREAS)

Forrest G. Hall and Karl Huemmrich, Editors

Volume 191

BOREAS TF-1 SSA-OA

Weekly Tower CH 4 and N20 Flux

George Thurtell and Grant Edwards, University of Guelph, Ontario

Isobel Simpson, University of California, Irvine

National Aeronautics and

Space Administration

Goddard Space Flight Center

Greenbelt, Maryland 20771

October 2000
NASA Center for AeroSpace Information

7121 Standard Drive

Hanover, MD 21076-1320

Price Code: A17

Available from:

National Technical Information Service

5285 Port Royal Road

Springfield, VA 22161

Price Code: A10
BOREAS TF-1 SSA-OA Weekly Tower CH 4 and N20 Flux

George Thurtell, Grant Edwards, Isobel Simpson

Summary

The BOREAS TF-1 team collected various trace gas and energy flux data in its efforts to characterize

the temporal energy and gas exchanges that occurred over the SSA-OA site. This data set contains

methane (CH4) and nitrous oxide (N20) fluxes that were measured at the BOREAS SSA-OA site.

These fluxes were measured from 16-Apr to 16-Sep-1994. The data were averaged to weekly values

and are available 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 TF-01 SSA-OA Weekly Tower CH4 and N20 Flux

1.2 Data Set Introduction

Fluxes of CH4 and N20 were measured at the BOReal Ecosystem-Atmosphere Study (BOREAS)

Southern Study Area (SSA) Old Aspen (OA) site. These fluxes were measured through the growing

season of 1994. The tower-based fluxes were determined using a high-resolution tunable diode laser

Trace Gas Analysis System (TGAS) together with micrometeorological techniques. The fluxes were

small and required long averaging times to be resolved. Half-hour averages were determined and these

were averaged to weekly values.

Page 1
1.3 Objective/Purpose

The global budgets of CH4 and N20 are poorly constrained, and several priority trace gas research

areas have been specified, including the boreal forest. The objectives of this research were to quantify

the exchange of CH4 and N20 at the aspen site and to better understand the factors that control their

exchange.

1.4 Summary of Parameters and Variables

Half-hour observations were combined to produce weekly CI_ and N20 flux values. The data set

includes weekly average, standard error, and number of half-hourly values used to calculate the

average, for both CI_ and N20. By convention, a positive flux indicates trace gas emission, and a

negative flux indicates uptake.

1.5 Discussion

Boreal forests have been reported as net sinks of CH4, although the uptake of CH4 by soils has not

been well characterized. CH4 oxidation in moist soils may be a negative feedback on atmospheric CH4

increases. Generally, there is a lack of N20 for all northern ecosystems.

1.6 Related Data Sets

BOREAS TF-02 SSA-OA Tower Flux and Meteorological Data

BOREAS TF-01 SSA-OA Undercanopy Flux, Meteorological, and Soil Temperature Data

BOREAS TF-04 CO2 and CH4 Chamber Flux Data from the SSA

2. Investigator(s)

2.1 Investigator(s) Name and Title

George Thurtell, University of Guelph

Grant Edwards, University of Guelph

2.2 Title of Investigation

Boreal Forest Atmosphere Interactions: Exchanges of Energy, Water Vapor, and Trace Gases

2.3 Contact Information

Contact 1:

Isobel Simpson

Chemistry Department

University of California, Irvine

Irvine, CA 92697

(949) 824-6024

(949) 824-2905 (fax)

isimpson@uci.edu

Contact 2:

Grant Edwards

University of Guelph

Department of Land Resource Science

Guelph, Ontario

Canada N1G 2W1

(519) 824-5730 (fax)

gedwards@net2.eos.uoguelph.ca

Page 2
Contact 3:

George Thurtell

University of Guelph

Department of Land Resource Science

Guelph, Ontario

Canada N1G 2W1

(519) 824-4120

(519) 824-5730 (fax)

gthurtel@lrs.uoguelph.ca

Contact 4:

K. Fred Huemmrich

University of Maryland

Code 923

NASA GSFC

Greenbelt, MD 20771

(301) 286-4862

(301) 286-0239 (fax)

Karl.Huemmrich@gsfc.nasa.gov

3. Theory of Measurements

The tower-based fluxes were determined using the flux-gradient method. Measurements were made of

the concentration differences of CH< and N20 between 26.8 and 37.5 m above the forest floor. The

canopy height was 22 m. Air was alternately sampled from either level every 4 seconds, and the

resulting concentration differences were averaged over half an hour. Micrometeorological data

collected at 39.1 m using a sonic anemometer were used to determine a transfer coefficient. Together,

the concentration differences and stability-corrected transfer coefficient were used to determine the flux

of CH4 and N20 in the following flux-gradient relationship:

Flux -

- [ ustar k (conc2 - concl) ]

(z2 - d)

0.74 [ in { } - psih2 + psihl ]

(zl - d)

where ustar is the friction velocity [m/s]; k is yon Karman's constant (taken as 0.4); z2 and zl are the

upper (37.5 m) and lower (26.8 m) sampling heights, respectively; conc2 and conc 1 are the respective

concentrations [ng/m3] at z2 and zl; d is the zero plane displacement; and psih2 and psihl are the

respective scalar diabatic correction functions at z2 and z 1.

A value for the zero plane displacement was determined before, during, and after leaf-out using

sonic anemometer data collected during times of neutral atmospheric stability.

Page 3
4. Equipment

4.1 Sensor/Instrument Description

4.1.1 Collection Environment

Data were collected through the growing season of 1994. The site was burned approximately 80

years ago, and the primary forest cover was trembling aspen (Populus tremuloides) with some balsam

poplar (Populus balsamifera). The aspen canopy architecture features an open trunk space with the

crown concentrated at the top 5-6 m of the trees. The maximum aspen leaf area index in 1994 was 2.4.

There was a rich understory comprising 60% hazelnut (Corylus cornuta) and 15% wild rose (Rosa

woodsii). The soil is classified as an Orthic Gray Aluvisol, featuring a well- to moderately

well-drained loam to clay loam till and an organic layer depth less than 8 cm.

4.1.2 Source/Platform

Measurements were made from a 37-m double-scaffold walk-up tower. Two Campbell Scientific

tunable diode laser TGAS were used to measure the concentration differences of CH< and N20

between 26.8 and 37.5 m above the forest floor. Air was alternately sampled from either level every 4

seconds, and the resulting concentration differences were averaged over half an hour.

Micrometeorological data collected at 39.1 m using a 20-cm-path Kaijo-Denke sonic anemometer were

used to determine a transfer coefficient.

4.1.3 Source/Platform Mission Objectives

The purpose of the tower was to suspend instruments to measure trace gas, energy fluxes, and

meteorological variables above a mature aspen stand.

4.1.4 Key Variables

Half-hour observations were combined to produce weekly CH< and N20 flux values. The data set

includes weekly average, standard error, and number of half-hourly values used to calculate the

average, for both CI4< and NzO. By convention, a positive flux indicates trace gas emission, and a

negative flux indicates uptake.

4.1.5 Principles of Operation

Laser-based trace gas analysis is based on absorption spectroscopy, whereby each molecule is

known to absorb radiation in a characteristic spectrum. In the TGAS unit, a lead-salt laser is housed in

a liquid nitrogen-cooled Dewar. The laser beam is sent through a single-path, 1.5-m sample tube, and

then is split into sample and reference gas cells, each housing a Peliter-cooled

cadmium-mercury-telluride detector. Air sampled from outside is pumped through the sample tube,

where it encounters the laser beam. A good absorption line is selected based on its strength and the

absence of interference by other absorbing gases. The laser emission is tunable, and the laser is

modulated to scan back and forth across the entire absorption feature 500 times a second. The area

under the absorption feature is integrated to determine the concentration of the trace gas within the air

sample. Concentration readings are output at 10 Hz, and each reading is calibrated in real time against a

reference gas (in this case CH4 or NzO) of known concentration.

4.1.6 Sensor/Instrument Measurement Geometry

Air intakes were located on the SSA-OA flux tower at 0.5, 5.0, 18.1, 26.8, and 37.5 m above the

ground. Concentration differences were determined in 4-hour cycles between each pair of intakes with

an emphasis on the above canopy measurements (the 26.8- and 37.5-m intakes). The air from the

upper and lower intakes passed through an equal amount of 0.5-inch inner diameter (i.d.) high-density

polyethylene tubing to a common Perma Pure dryer located on the tower. A total of four dryers were

installed on the tower, one for each pair of intakes.

Page 4
4.1.7 Manufacturer of Sensor/Instrument

TGASunits:

Campbell Scientific, Inc.

815 West 1800 North

Logan, UT 84321-1784

(435) 753-2342

(435) 750-9540 (fax)

info@campbellsci.com

4.2 Calibration

4.2.1 Specifications

Concentration readings from TGAS were output at 10 Hz. Each reading is calibrated in real time

against a reference gas (in this case CH4 or N20) of known concentration.

4.2.1.1 Tolerance

See Section 9.2.1.

4.2.2 Frequency of Calibration

Calibration against a reference gas was done in real time.

4.2.3 Other Calibration Information

None.

5. Data Acquisition Methods

A suite of four concentration differences was measured between five levels both above and within the

aspen canopy. The concentration differences were determined in a 4-hour cycle, with emphasis on the

above-canopy measurements. The TGAS units operated 24 hours a day over the 5 months of

measurement, with about 1 hour of data edited out each day during liquid nitrogen fills.

A five-way Whitey ball valve (model SS-45ZF8-42ACZ) with an electric actuator (model

MS-142ACZ) was used to switch the sampling among air intakes. For a given pair of intakes, a

Numatics solenoid valve (model 152SS-400K) located on the tower was used to alternately draw

sample air from the upper and lower intakes every 4 s. Rapid switching between the two levels acts as

a high-pass filter and therefore reduces the low-frequency noise.

The air from the upper and lower intakes passed through an equal amount of 0.5-inch i.d. high

density polyethylene tubing to a common Perma Pure dryer (model PD-1000-SS48) located on the

tower. A total of four dryers were installed on the tower, one for each pair of intakes. Drying is

necessary to avoid corrections to the flux measurements for density effects caused by water vapor

transfer.

The dried air then was pumped at low pressure through tubes from the tower to a hut housing the

TGAS units. Travel through a common long tube ensured that the upper and lower air samples had a

common temperature by the time they reached the TGAS units. A Whitey needle valve (model

SS-3NRM4) positioned at the end of each dryer was used to create a pressure drop, and the pressure

in each TGAS unit was maintained at 75 mbar. The concentration readings recovered from the solenoid

valve switch in 0.6-0.7 s, and the first 0.8 s of data were discarded following each 4-s switch. Delay

times to account for the travel time down the tubes were also set in the TGAS units.

The sample air was split and diverted through the two TGAS units in parallel,. The air was then

exhausted through a Busch pump (model RA-0040-A005-1002) at 22 actual ft3/min.

Page 5
6. Observations

6.1 Data Notes

None.

6.2 Field Notes

The TGAS concentration differences were edited out during liquid nitrogen fills (twice daily),

power surges, laser alignment, etc.

7. Data Description

7.1 Spatial Characteristics

7.1.1 Spatial Coverage

All data were collected at the BOREAS SSA-OA site. North American Datum of 1983 (NAD83)

coordinates for the site are latitude 53.62889 ° N, longitude 106.19779 ° W, and elevation of 600.63 m.

7.1.2 Spatial Coverage Map

Not applicable.

7.1.3 Spatial Resolution

Large eddy simulations using characteristics appropriate for the aspen site indicated that under

neutral atmospheric stability, 90% of the measured trace gas flux, was expected to originate from

within a distance of 2 km upwind of the tower, with a peak influence distance of 200 m.

7.1.4 Projection

Not applicable.

7.1.5 Grid Description

Not applicable.

7.2 Temporal Characteristics

7.2.1 Temporal Coverage

Fluxes were measured from 16-Apr to 16-Sep-1994. The data were averaged to weekly values.

7.2.2 Temporal Coverage Map

None.

7.2.3 Temporal Resolution

The fluxes were small and required long averaging times to be resolved. Half-hour averages were

determined, and these were averaged to weekly values.

7.3 Data Characteristics

Page 6
7.3.1 Parameter/Variable

The parameters contained in the data files on the CD-ROM are:

Column Name

SITE NAME

SUB SITE

START DATE

END DATE

MEAN WEEKLY CH4 FLUX

STD ERR WEEKLY CH4 FLUX

NUM WEEKLY CH4 FLUX

MEAN WEEKLY N20 FLUX

STD ERR WEEKLY N20 FLUX

NUM WEEKLY N20 FLUX

CRTFCN CODE

REVISION DATE

7.3.2 Variable Description/Definition

The descriptions of the parameters contained in the data files on the CD-ROM are:

Column Name Description

SITE NAME

SUB SITE

START DATE

END DATE

MEAN WEEKLY CH4 FLUX

STD ERR WEEKLY CH4 FLUX

NUM WEEKLY CH4 FLUX

MEAN WEEKLY N20 FLUX

STD ERR WEEKLY N20 FLUX

NUM WEEKLY N20 FLUX

The identifier assigned to the site by BOREAS, in

the format SSS-TTT-CCCCC, where SSS identifies

the portion of the study area: NSA, SSA, REG,

TRN, and TTT identifies the cover type for the

site, 999 if unknown, and CCCCC is the identifier

for site, exactly what it means will vary with

site type.

The identifier assigned to the sub-site by BOREAS,

in the format GGGGG-IIIII, where GGGGG is the

group associated with the sub-site instrument,

e.g. HYD06 or STAFF, and IIIII is the identifier

for sub-site, often this will refer to an

instrument.

The date on which the collection of data

commenced.

The date on which the collection of the data was

terminated.

The weekly averaged methane flux, based on half

hour methane fluxes.

The standard error of the weekly averaged methane

flux, based on half hour methane fluxes.

The number of half hour flux values used in

calculating the weekly averaged methane flux.

The weekly averaged nitrous oxide flux, based on

half hour nitrous oxide fluxes.

The standard error of the weekly averaged nitrous

oxide flux, based on half hour nitrous oxide

fluxes.

The number of half hour flux values used in

calculating the weekly averaged nitrous oxide

flux.

Page 7
CRTFCN CODE

REVISION DATE

The BOREAS certification level of the data.

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

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

but questionable).

The most recent date when the information in the

referenced data base table record was revised.

7.3.3 Unit of Measurement

The measurement units for the parameters contained in the data files on the CD-ROM are:

Column Name Units

SITE NAME

SUB SITE

START DATE

END DATE

MEAN WEEKLY CH4 FLUX

STD ERR WEEKLY CH4 FLUX

MUM WEEKLY CH4 FLUX

MEAN WEEKLY N20 FLUX

STD ERR WEEKLY N20 FLUX

MUM WEEKLY N20 FLUX

CRTFCN CODE

REVISION DATE

[none]

[none]

[DD-MON-YY]

[DD-MON-YY]

[nanomoles] [meters^-2] [second^-l]

[nanomoles] [meters^-2] [second^-l]

[counts]

[nanomoles] [meters^-2] [second^-l]

[nanomoles] [meters^-2] [second^-l]

[counts]

[none]

[DD-MON-YY]

7.3.4 Data Source

The sources of the parameter values contained in the data files on the CD-ROM are:

Column Name Data Source

SITE NAME

SUB SITE

START DATE

END DATE

MEAN WEEKLY CH4 FLUX

STD ERR WEEKLY CH4 FLUX

MUM WEEKLY CH4 FLUX

MEAN WEEKLY N20 FLUX

STD ERR WEEKLY N20 FLUX

MUM WEEKLY N20 FLUX

CRTFCN CODE

REVISION DATE

[Assigned by BORIS.]

[Assigned by BORIS.]

[Supplied by Investigator.]

[Supplied by Investigator.]

[TGAS and sonic anemometer]

[TGAS and sonic anemometer]

[Supplied by Investigator.]

[TGAS and sonic anemometer]

[TGAS and sonic anemometer]

[Supplied by Investigator.]

[Assigned by BORIS.]

[Assigned by BORIS.]

7.3.5 Data Range

The following table gives information about the parameter values found in the data files on the

CD-ROM.

Minimum Maximum Missng Unrel Below Data

Data Data Data Data Detect Not

Column Name Value Value Value Value Limit Cllctd

SITE NAME SSA-9OA-FLXTR SSA-9OA-FLXTR None None None None

SUB SITE 9TF01-FLX01 9TF01-FLX01 None None None None

START DATE 17-APR-94 II-SEP-94 None None None None

END DATE 23-APR-94 17-SEP-94 None None None None

Page 8
MEAN WEEKLY CH4 FLUX -.22375

STD ERR WEEKLY CH4 .30813

FLUX

NUM WEEKLY CH4 FLUX 35

MEAN WEEKLY N20 FLUX -.1225

STD ERR WEEKLY N20 .04023

FLUX

NUM WEEKLY N20 FLUX 35

CRTFCN CODE CPI

REVISION DATE 24-MAY-99

5.33 None None None None

2.09 None None None None

115 None None None None

.16341 None None None None

.11909 None None None None

120 None None None None

CPI None None None None

24-MAY-99 None None None None

Minimum Data Value --

Maximum Data Value --

Missng Data Value --

Unrel Data Value --

Below Detect Limit --

Data Not Cllctd --

The minimum value found in the column.

The maximum value found in the column.

The value that indicates missing data. This is used to

indicate that an attempt was made to determine the

parameter value, but the attempt was unsuccessful.

The value that indicates unreliable data. This is used

to indicate an attempt was made to determine the

parameter value, but the value was deemed to be

unreliable by the analysis personnel.

The value that indicates parameter values below the

instruments detection limits. This is used to

indicate that an attempt was made to determine the

parameter value, but the analysis personnel determined

that the parameter value was below the detection

limit of the instrumentation.

This value indicates that no attempt was made to

determine the parameter value. This usually

indicates that BORIS combined several similar but

not identical data sets into the same data base table

but this particular science team did not

measure that parameter.

Blank

N/A

None

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

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

-- Indicates that no values of that sort were found in the column.

7.4 Sample Data Record

The following are wrapped versions of data record from a sample data file on the CD-ROM.

SITE NAME,SUB SITE,START DATE,END DATE,MEAN WEEKLY CH4 FLUX,

STD ERR WEEKLY CH4 FLUX,NUM WEEKLY CH4 FLUX,MEAN WEEKLY N20 FLUX,

STD ERR WEEKLY N20 FLUX,NUM WEEKLY N20 FLUX,CRTFCN CODE,REVISION DATE

'SSA-9OA-FLXTR', '9TF01-FLX01',I7-APR-94,23-APR-94,-.13125, .93125,50,-.1225,

.11909,

50, 'CPI',24-MAY-99

'SSA-9OA-FLXTR', '9TF01-FLX01',24-APR-94,30-APR-94, .6325, .78688,72,-.05932,

.i0727,67, 'CPI',24-MAY-99

Page 9
8. Data Organization

8.1 Data Granularity

The smallest unit of data tracked by the BOREAS Information System (BORIS) was data collected

at a given site on a given date.

8.2 Data Format

The Compact Disk-Read-Only Memory (CD-ROM) files contain American Standard Code for

Information Interchange (ASCII) numerical and character fields of varying length separated by

commas. The character fields are enclosed with single apostrophe marks. There are no spaces between

the fields.

Each data file on the CD-ROM has four header lines of Hyper-Text Markup Language (HTML)

code at the top. When viewed with a Web browser, this code displays header information (data set

title, location, date, acknowledgments, etc.) and a series of HTML links to associated data files and

related data sets. Line 5 of each data file is a list of the column names, and line 6 and following lines

contain the actual data.

9. Data Manipulations

9.1 Formulae

9.1.1 Derivation Techniques and Algorithms

The fluxes of CH4 and N20 were determined in the following flux-gradient relationship:

Flux -

- [ ustar k (conc2 - concl) ]

(z2 - d)

0.74 [ in { } - psih2 + psihl ]

(zl - d)

where: ustar is the friction velocity [m/s]

k is von Karman's constant (taken as 0.4)

z2 and zl are the upper (37.5 m) and lower (26.8 m) sampling heights

conc2 and concl are the respective concentrations [ng/m3] at z2 and zl

d is the zero plane displacement

psih2 and psihl are the respective scalar diabatic correction functions at z2 and zl

9.2 Data Processing Sequence

9.2.1 Processing Steps

The editing criteria applied to the 39.1-m sonic anemometer data in preliminary analysis include:

• Measured horizontal windspeed (Umeas) > 1.5 m/s.

• Calculated horizontal windspeed (Ucalc) > 1.5 m/s. Ucalc was determined from the

logarithmic wind profile equation using ustar from the sonic anemometer.

• Zeta ( [z-d]/L ) between -10 and 2, where L is the Monin-Obukhov length.

• The ratio of Umeas and Ucalc between 0.8 and 1.2.

BORIS staff processed these data by:

• Reviewing the initial data files and loading them online for BOREAS team access.

• Designing relational data base tables to inventory and store the data.

• Loading the data into the relational data base tables.

• Working with the team to document the data set.

• Extracting the data into logical files.

Page 10
9.2.2 Processing Changes

None.

9.3 Calculations

9.3.1 Special Corrections/Adjustments

None.

9.3.2 Calculated Variables

See Section 9.1.1.

9.4 Graphs and Plots

None.

10. Errors

10.1 Sources of Error

Wind speed editing was introduced because sonic anemometers can give error at low wind speeds

due to flow distortion around the transducers.

10.2 Quality Assessment

10.2.1 Data Validation by Source

Quality checks were made as part of the data processing to remove poor data values. See Section

9.2.1.

10.2.2 Confidence Level/Accuracy Judgment

The half-hour above-canopy trace gas concentration differences were often close to the resolution

of the TGAS units for both CH4 and N20.

10.2.3 Measurement Error for Parameters

None.

10.2.4 Additional Quality Assessments

None.

10.2.5 Data Verification by Data Center

BOREAS Information System staff reviewed the data and documentation for clarity and

consistency.

1 1. Notes

11.1 Limitations of the Data

The sonic anemometer and the TGAS units operated 24 hours a day, and the edited data include

half hours collected in both the daytime and the nighttime. 1994 was a record warm, frost-free year in

the BOREAS SSA.

11.2 Known Problems with the Data

None.

11.3 Usage Guidance

None.

Page 11
11.4 Other Relevant Information

Overall, the preliminary analysis indicates a small net upwards N20 flux of 1.5+0.7 ng/m2/s from

April to September 1994. N20 is produced by soil bacteria during nitrification and denitrification, and

these initial results suggest that this forest is efficient in its use of nitrogen. The data also show an

overall CI_ emission of 24+5 ng/n_/s during the measurement period. Well-aerated soils in temperate

and tropical regions have been shown to consume CH4, and we had also expected to see CH4

consumption at the OA site. We have carefully investigated the CH4 results, and we believe the

upwards CH4 fluxes to be real. We are continuing to investigate the observed emission of CH4 from

the OA stand. However, at this time we expect that CH< emissions from warm, wet areas located

throughout the footprint were greater than CH< uptake in drier areas, to give a net upwards flux of

CH4 during the measurement period.

12. Application of the Data Set

These data are useful for the study of nitrogen and carbon exchange in a mature aspen forest.

13. Future Modifications and Plans

We are continuing to assess our data selection criteria, and we remind BORIS users that these results

are preliminary only and may change after further analysis.

14.1 Software Description

None given.

14.2 Software Access

None given.

14. Software

15. Data Access

The SSA-OA weekly tower CH4 and N20 flux data are available from the Earth Observing System

Data and Information System (EOSDIS) Oak Ridge National Laboratory (ORNL) Distributed Active

Archive Center (DAAC).

15.1 Contact Information

For BOREAS data and documentation please contact:

ORNL DAAC User Services

Oak Ridge National Laboratory

P.O. Box 2008 MS-6407

Oak Ridge, TN 37831-6407

Phone: (423) 241-3952

Fax: (423) 574-4665

E-mail: ornldaac@oml.gov or oml@eos.nasa.gov

Page 12
15.2 Data Center Identification

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

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

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

15.3 Procedures for Obtaining Data

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

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

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

information in Section 15.1.

15.4 Data Center Status/Plans

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

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

CD-ROM are available from the ORNL DAAC.

16. Output Products and Availability

16.1 Tape Products

None.

16.2 Film Products

None.

16.3 Other Products

These data are available on the BOREAS CD-ROM series.

17. References

17.1 Platform/Sensor/Instrument/Data Processing Documentation

None.

17.2 Journal Articles and Study Reports

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

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

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

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

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

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

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

Sellers, P., F. 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).

Page 13
Sellers,P.,F. Hall, H. Margolis,B. Kelly, D. Baldocchi,G. denHartog,J.Cihlar, M.G. Ryan,B.

Goodison,P.Crill, K.J.RansomD. Lettenmaier,andD.E. Wickland. 1995.Theboreal

ecosystem-atmospherestudy(BOREAS):anoverviewandearlyresultsfrom the1994field year.

Bulletinof theAmericanMeteorologicalSociety.76(9):1549-1577.

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

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

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

in 1997:ExperimentOverview,ScientificResultsandFutureDirections.Journalof Geophysical

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

Simpson,I.J., G.C.Edwards,G.W. Thurtell, G. denHartog,H.H. Neumann,andR.M. Staebler.

1997.Micrometeorologicalmeasurementsof methaneandnitrousoxideexchangeaboveaborealaspen

forest.Journalof GeophysicalResearch102(D24):29,331-29,341.

17.3 Archive/DBMS Usage Documentation

None.

None.

18. Glossary of Terms

ASCII

BOREAS

BORIS

CD-ROM

DAAC

EOS

EOSDIS

GIS

GMT

GSFC

HTML

i.d.

IFC

NAD83

NASA

NSA

OA

ORNL

PANP

SSA

TF

TGAS

URL

19. List of Acronyms

- American Standard Code for Information

- BOReal Ecosystem-Atmosphere Study

- BOREAS Information System

- Compact Disk-Read-Only Memory

- Distributed Active Archive Center

- Earth Observing System

- EOS Data and Information System

- Geographic Information System

- Greenwich Mean Time

- Goddard Space Flight Center

- Hyper-Text Markup Language

- Inner diameter

- Intensive Field Campaign

- North American Datum of 1983

- National Aeronautics and Space

- Northern Study Area

- Old Aspen

- Oak Ridge National Laboratory

- Prince Albert National Park

- Southern Study Area

- Tower Flux

- Trace Gas Analysis System

- Uniform Resource Locator

Interchange

Administration

Page 14
20. Document Information

20.1 Document Revision Date

Written: 03-Jun- 1999

Revised: 22-Nov- 1999

20.2 Document Review Date(s)

BORIS Review: 10-Jun-1999

Science Review:

20.3 Document ID

20.4 Citation

When using these data, please include the following acknowledgment:

Data were collected and processed by Isobel Simpson, Grant Edwards, George Thurtell. The

results are described in the paper Simpson et al., 1997.

If using data from the BOREAS CD-ROM series, also reference the data as:

Simpson, I.J., G.C. Edwards, G.W. Thurtell, and T.A. Black, "Boreal Forest Atmosphere

Interactions: Exchanges of Energy, Water Vapor, and Trace Gases." In Collected Data of The Boreal

Ecosystem-Atmosphere Study. Eds. J. Newcomer, D. Landis, S. Conrad, S. Curd, K. Huemmrich,

D. Knapp, A. Morrell, J. Nickeson, A. Papagno, D. Rinker, R. Strub, T. Twine, F. Hall, and P.

Sellers. CD-ROM. NASA, 2000.

Also, cite the BOREAS CD-ROM set as:

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

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

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

20.5 Document Curator

20.6 Document URL

Page 15
REPORT DOCUMENTATION PAGE FormApproved

OMB No. 0704-0188

Public reporting burden for this collection of informationis estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources,

gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this

collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson

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

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

October 2000 Technical Memorandum

4. TITLE AND SUBTITLE 5. FUNDING NUMBERS

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

BOREAS TF-1 SSA-OAWeekly Tower CH 4 and N20 Flux 923

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

George Thurtell, Grant Edwards, and Isobel Simpson

Forrest G. Hall and Karl Huemmrich, Editors

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

Goddard Space Flight Center

Greenbelt, Maryland 20771

9. SPONSORING / MONITORING AGENCY NAME(S) AND ADDRESS (ES)

National Aeronautics and Space Administration

Washington, DC 20546-0001

8. PEFORMING ORGANIZATION

REPORT NUMBER

2000-03136-0

10. SPONSORING / MONITORING

AGENCY REPORT NUMBER

TM--2000-209891

Vol. 191

11. SUPPLEMENTARY NOTES

G. Thurtell, G. Edwards, and I. Simpson: University of Guelph, Ontario;

K. Huemmrich: University of Maryland, NASA Goddard Space Flight Center, Greenbelt, Maryland

12a. DISTRIBUTION / AVAILABILITY STATEMENT

Unclassifie_Unlimited

Subject Category: 43

Report available from the NASA Center for AeroSpace Information,

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

12b. DISTRIBUTION CODE

13. ABSTRACT (Maximum 200 words)

The BOREAS TF-1 team collected various trace gas and energy flux data in its efforts to characterize

the temporal energy and gas exchanges that occurred over the SSA-OA site. This data set contains

methane (CU4) and nitrous oxide (N20) fluxes that were measured at the BOREAS SSA-OA site.

These fluxes were measured from 16-Apr to 16-Sep-1994. The data were averaged to weekly values

and are available in tabular ASCII files.

14. SUBJECT TERMS

BOREAS, tower flux.

17. SECURITY CLASSIFICATION

OF REPORT

Unclassified

NSN 7540-01-280-5500

18. SECURITY CLASSIFICATION

OF THIS PAGE

Unclassified

19. SECURITY CLASSIFICATION

OF ABSTRACT

Unclassified

15. NUMBER OF PAGES

15

16. PRICE CODE

20. LIMITATION OF ABSTRACT

UL

Standard Form 298 (Rev. 2-89)

Prescribed by ANSI Std. Z39.18

298-102