NASA/TMm2000-209891, Vol. 227

Technical Report Series on the

Boreal Ecosystem-Atmosphere Study (BOREAS)

Forrest G. Hall and Sara K. Conrad, Editors

Volume 227

BOREAS TGB-4 NSA-BVP Tower

Flux and Meteorological Data

Nigel T. Roulet

McGill University, Montreal, Quebec

National Aeronautics and

Space Administration

Goddard Space Flight Center

Greenbelt, Maryland 20771

November 2000

https://ntrs.nasa.gov/search.jsp?R=20010022580 2018-05-14T19:01:46+00:00Z
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NASA/TMm2000-209891, Vol. 227

Technical Report Series on the

Boreal Ecosystem-Atmosphere Study (BOREAS)

Forrest G. Hall and Sara K. Conrad, Editors

Volume 227

BOREAS TGB-4 NSA-BVP Tower

Flux and Meteorological Data

Nigel T. Roulet

McGill University, Montreal, Quebec

National Aeronautics and

Space Administration

Goddard Space Flight Center

Greenbelt, Maryland 20771

November 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 TGB-4 NSA-BVP Tower Flux and Meteorological Data

Nigel T. Roulet

Summary

The BOREAS TGB-4 team measured the exchange of heat, water, and CO2 between a boreal forest

beaver pond and the atmosphere in the NSA for the ice-free period of BOREAS. The data cover the

period of 28-May to 18-Sep-1994. The data 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 TGB-04 NSA-BVP Tower Flux and Meteorological Data

1.2 Data Set Introduction

This data set includes heat, CO2, and water vapor fluxes measured from the BOReal

Ecosystem-Atmosphere Study (BOREAS) Northern Study Area (NSA)-Beaver Pond (BVP) tower.

Anemometer, temperature (wet and dry bulb), and CO2 profile measurements were collected from a

tower located in the middle of a beaver pond. These data along with radiometric measurements were

used to calculate the surface turbulent fluxes using the profile and energy balance technique.

Measurements of the water level, flow rates, and light penetration of the beaver pond were also

collected.

Page 1
1.3 Objective/Purpose

Theobjectiveof this studywasto quantifytheexchangeof heat,water,andC02 between boreal

forest beaver ponds and the atmosphere for the ice-free period of BOREAS. The fluxes of heat, water,

and CO2 from one beaver pond were measured continuously using the energy balance Bowen ratio

approach. The diffuse and bubble flux CH4 were measured several times a week using chambers. The

chamber approach was used to sample CO2 and CH4 flux from four to five additional beaver ponds,

once every 2 weeks, and regional surveys of the surface concentrations of CO2, CH4, and dissolved

organic carbon (DOC) were carried out on accessible beaver ponds.

1.4 Summary of Parameters

Variables measured include latent heat flux, sensible heat flux, soil heat flux, CO 2 flux, net

radiation, incident and reflected Photosynthetically Active Radiation (PAR), underwater PAR, incident

and reflected solar radiation, wind speed and direction, precipitation amount, air temperature, vapor

pressure, air pressure, flow rate of water out of the pond, and water table height.

1.5 Discussion

In BOREAS, each surface flux station was located in a unique boreal forest ecosystem component

in northern and southern study areas, in an attempt to characterize the boreal forest at both the northern

and southern extremes of its extent. In this study, the surface flux station was deployed in a beaver

pond to make measurements of the fluxes of CO2, CH4, and the energy budget components. These

fluxes were considered important in characterizing wetlands of the boreal forest. The surface fluxes

were measured using the profile and energy balance technique. Supporting meteorological

measurements were also made at this site.

1.6 Related Data Sets

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

BOREAS TF- 10 NSA-Fen Tower Flux and Meteorological Data

BOREAS TF- 11 SSA-Fen Tower Flux and Meteorological Data

2. Investigator(s)

2.1 Investigator(s) Name and Title

Dr. N.T. Roulet

Department of Geography

McGill University

2.2 Title of Investigation

The Fluxes of Energy and Trace Gases from Beaver Ponds and Dry Upland Forest Floor in the

NSA

2.3 Contact Information

Contact 1:

Dr. N.T. Roulet

Department of Geography

McGill University

805 Sherbrooke St. W.

Montreal, Quebec, Canada H3A 2K6

(514) 398-4945

(514) 398-7437 (fax)

roulet@ felix.geog.mcgill.ca

Page 2
Contact 2:

K. FredHuemmrich

Universityof Maryland

NASA GSFC

Code923

Greenbelt,MD 20771

(301)286-4862

(301)286-0239(fax)

Karl.Huemmrich@gsfc.nasa.gov

3. Theory of Measurements

A four-level profile measurement system of temperature, wind speed, humidity, and C02 were used to

calculate the flux of sensible heat, momentum, latent heat, and CO2, respectively, from a tower located

in the middle of a beaver pond. According to well-accepted footprint theory, the tower was sufficiently

low to the ground to obtain flux measurements representative of the pond and not the surrounding

forested area. Differential measurements between levels were then used to calculate the actual fluxes

based upon the well-proven profile technique.

4. Equipment

4.1 Sensor/Instrument Description

Instrumentation at this site was fairly elaborate. The basis of the system was the Campbell

Scientific CR7 data logger, which controlled operation and saved incoming data for later analysis. Also

included was a LI-COR model 6252 CO2 analyzer capable of measuring CO2 concentrations at a fast

sampling rate.

Measurements were collected from a short tower using a profile system at 25 cm, 50 cm, 100 cm,

and 150 cm above the pond surface. Gas sampling locations were switched automatically by the data

logger, allowing sufficient time to purge the sampling lines of the previous level's air before a

measurement was taken.

Due to the fluctuating nature of the pond surface height, continuous measurements were made of

its movement (by potentiometer). The surface heights were then used to correct the actual height of the

instruments above the water surface as this greatly affects the calculated fluxes.

4.1.1 Collection Environment

Measurements were collected from the end of May through mid-September of 1994. Over that time

period, temperature conditions ranged from slightly below freezing to about 28 °C.

4.1.2 Source/Platform

A ground-based platform was situated on a stable dock-like structure in the center of the pond. It

was accessible by a floating boardwalk. The tower was mounted on this dock, and the profile

instruments were placed at the appropriate levels and wired back to a low-profile instrument box also

on this dock. Within this box were the data logger, CO2 analyzer, gas sampler switching system (from

one level to the next), and power supply panel and converter from 120V AC to 12V DC.

4.1.3 Source/Platform Mission Objectives

The mission objective was to collect continuous energy balance and CO 2 fluxes from an active

beaver pond surface.

Page 3
4.1.4 Key Variables

Profile measurements, all at 0.25, 0.5, 1.0, and 1.5 m:

• Temperature profile (using thermocouples)

• Moisture profile (using thermocouples and wet/dry bulb technique)

• Wind speed profile

• CO2 concentration

• CH4 concentration

Nonprofile measurements:

• Water table measurements referenced to lowest instrument profile level (0.25 m)

• Incoming solar radiation (up-facing pyranometer)

• Outgoing solar radiation (down-facing pyranometer)

• Net radiation (all-wave radiometer)

• Water temperature profile (1 cm, 5 cm, 10 cm, 20 cm) (using thermocouples)

• Atmospheric pressure at surface

• Incoming PAR

• Outgoing PAR

• Wind direction

• Precipitation

• Underwater PAR

4.1.5 Principles of Operation

The calculation of fluxes required a calculation based upon measured momentum flux. Wind speed

profiles determine the momentum flux toward the surface and the associated transfer coefficient Km is

calculated and corrected for stability by temperature profile measurements. Using similarity theory, the

same transfer coefficient is applied to the fluxes of sensible and latent heat, and CO2 using the formula

of the form:

Flux = K x dA/dz

where K is the eddy diffusivity or transfer coefficient, and the second term is the gradient of the entity

concerned. A good review of the procedures used is found within Oke (1987), Appendix A2, Section

2b. Given the calculations of sensible and latent heat and measured net, incoming, and outgoing

radiation, this allows closure of the energy and surface balance equations by attributing the difference

to the ground heat flux (Qg).

4.1.6 Sensor/Instrument Measurement Geometry

All profile measurements collected data at heights of 0.25, 0.5, 1.0, and 1.5 m above the water

surface when established, with water surface fluctuation accounted for during operation.

Wind direction, incoming and outgoing radiation sensors, and net radiation were measured 2 m

above established water surface.

Atmospheric pressure and precipitation were measured on the tower platform.

4.1.7 Manufacturer of Sensor/Instrument

Thermocouples (for both dry and wet bulb):

Type T

Supplier: Electrosonic, Inc.

1100 Gordon Baker Road

Willowdale, Ontario, Canada M2H 3B3

Page 4
DataLoggersandMultiplexes:

CampbellScientificCanadaCorp.

11564-149thStreet

Edmonton,AB, CanadaT5M 1W7

(403)454-2505

(403)454-2655(fax)

WaterTableMeasurement

TwentyTurnBournesPrecisionPotentiometers

Manufacturedby:Electrosonic,Inc.

1100GordonBakerRoad

Willowdale,Ontario,CanadaM2H 3B3

Anemometry:R.M. YoungCompany(viaCampbellScientific)

Winddirection:R.M.YoungCompany(viaCampbellScientific)

C02 concentration:

LI-CORModel6252GasAnalyzer

LI-COR, Inc.

P.O.Box 4425

Lincoln, NE 68504

(402)467-3576

Pyranometers:Kipp andZonen,ModelCM11

NetRadiometer:Middleton

Atmosphericpressure:Met-OneModel090B-4(viaCampbellScientific)

PAR Sensors:L-ICOR Model 'Quantum'

LI-COR, Inc.

P.O.Box 4425

Lincoln, NE 68504

(402)467-3576

UnderwaterPAR: LI-CORModel 'Underwater'

LI-COR, Inc.

P.O.Box 4425

Lincoln, NE 68504

(402)467-3576

Precipitation:Sierra/MISCO,Inc.,Tippingbucketmodel2501

Sierra/MISCO,Inc.

1825EastshoreHighway

Berkeley,CA 94710

Page5
4.2 Calibration

• Thermocouples:all calibratedbeforedeploymento ensuretherewerenooffsetsbetweenthe

psychrometers.Also, attheendof thefield season,all psychrometerswererunhorizontallyto

determineif anyoffsetshaddevelopedoverthesummer.

• Anemometry:calibratedpriorto deployment.

• Radiometricsensors(netradiation,PAR, solar):calibratedprior to deployment.

• CO2gasanalyzer:calibratedprior to setup,midsummer,andendof season.Notethatfor

theseprofilemeasurements, absoluteCO2concentrationneednotbeexact,sinceit is the

differencebetweenlevelsthatisimportanttocalculatetheflux.

• Waterlevel:apotentiometerandmachinedaluminumwheelcalibratedfromprevious

experimentswereused.Weeklymanualmeasurementsof watertabledepthweretakento

ensurepropercalibrationof theelectronicmeasurementwhichisrequiredto accountforthe

changingheightsof theinstrumentsabovethewatersurface.

4.2.1 Specifications

• Thermocouples:typeT thermocoupleratedat_+0.001°Cmaximumerror

• Anemometry:ratedat0.1m/swith astallspeedof 0.1m/s

• Winddirection:+ 2 °

• CO2 concentration: +0.1 ppm (0,02 ppm with 15-second averaging time used)

• Radiometry: approximately _+1.0 W/m2

• Water levels: maximum error of + 1 mm

• Precipitation: _+1mm

• Atmospheric pressure: +0.01 kPa

4.2.1.1 Tolerance

Thermocouples: range allowable: +62.5 °C of data logger temperature

Anemometry: range: within observable limits

CO2 concentration: 0 to 1000 ppm

Radiometry: within observable limits

Water levels range allowable: large; depends upon length of beaded cable

Atmospheric pressure: approximately 90-106 kPa

4.2.2 Frequency of Calibration

All instruments were calibrated once, before field deployment, except the gas analyzer, which was

also calibrated midsummer and checked again at the end of the field season.

4.2.3 Other Calibration Information

No corrections were required according to the calibration methods described above.

5. Data Acquisition Methods

Anemometer, temperature (wet and dry bulb), and C02 profile measurements on the tower, along with

radiometric measurements, were used to calculate the surface turbulent fluxes using the profile and

energy balance technique.

Each of these parameters was measured every 10 seconds and averaged, and then saved on the data

logger every 30 minutes. These data were later transferred to computer, where the energy and CO2

flux values were calculated using the standard flux-profile technique.

Radiometric, temperature, CO2, and pressure readings were made by differential voltage

measurements, which were multiplied by a calibration coefficient at the data logger and saved for later

download. A CO2 concentration at each level was determined once very 90 seconds.

The data logger controlled switching of the gas sampling ports (at each level) automatically by

solenoids, and saved the associated 30-minute average reading for later download.

Page 6
Forwaterlevelreadings,apotentiometervariedthevoltagemeasuredbythedataloggerasthefloat

(orbogshoe)onthebeadedcableroseandloweredin responseto watertablechanges.Thedata

loggermeasuredthischangingvoltage,whichwaseasilyconvertedintotheheightchangesincethe

potentiometerswerecalibratedto 1mV of changebeingequalto 1mmof verticalwaterchange.This

readingwassavedandusedfor therecalculationof instrumentheightsevery30minutes.

6. Observations

6.1 Data Notes

There are several periods of missing data within this set, due mainly to generator failure. In most

cases, these periods are less than 24 hours, since daily visits to check instrumentation were made

throughout the field campaign.

6.2 Field Notes

None.

7. Data Description

7.1 Spatial Characteristics

7.1.1 Spatial Coverage

All data were collected at the BOREAS NSA BVP site. North American Datum of 1983 (NAD83)

coordinates for the site are latitude 55.84225 ° N, longitude 98.02747 ° W, and elevation of 186.74 m.

7.1.2 Spatial Coverage Map

Not available.

7.1.3 Spatial Resolution

The tower was set up in the center of a beaver pond complex considered to be representative of this

environment according to standard footprint theory. The tower was placed to give a 150-m fetch in all

directions except for 310 ° to 100% In this section, the fetch was less than 100 m.

7.1.4 Projection

None.

7.1.5 Grid Description

None.

7.2 Temporal Characteristics

The data were collected continuously every 10 seconds for all variables except C02 concentration,

which was collected every 30 seconds. All readings were then averaged over 30-minute intervals (180

and 60 measurements, respectively, for average calculation).

7.2.1 Temporal Coverage

The data were collected during the summer of 1994 between the months of May and September.

7.2.2 Temporal Coverage Map

None.

7.2.3 Temporal Resolution

Resolution is 30 minutes. These represent average values of the previous 30 minutes.

Page 7
7.3 Data Characteristics

7.3.1 Parameter/Variable

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

Column Name

SITE NAME

SUB SITE

DATE OBS

TIME OBS

SENSIBLE HEAT FLUX ABV CNPY

LATENT HEAT FLUX ABV CNPY

NET RAD ABV CNPY

SOIL HEAT FLUX

CO2 FLUX ABV CNPY

DOWN PAR ABV CNPY

UP PAR ABV CNPY

DOWN PAR UNDER WATER

WIND DIR 200CM

WIND SPEED 100CM

AIR TEMP 100CM

VAPOR PRESS ABV CNPY

RAINFALL

DOWN SOLAR RAD ABV CNPY

UP SOLAR RAD ABV CNPY

SURF PRESS

WATER TABLE HGT

WATER OUTFLOW WEST

WATER OUTFLOW EAST

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

DATE OBS

TIME OBS

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 data were collected.

The Greenwich Mean Time (GMT) when the data were

collected.

Page 8
SENSIBLE HEAT FLUX ABV CNPY

LATENT HEAT FLUX ABV CNPY

NET RAD ABV CNPY

SOIL HEAT FLUX

CO2 FLUX ABV CNPY

DOWN PAR ABV CNPY

UP PAR ABV CNPY

DOWN PAR UNDER WATER

WIND DIR 200CM

WIND SPEED 100CM

AIR TEMP 100CM

VAPOR PRESS ABV CNPY

RAINFALL

DOWN SOLAR RAD ABV CNPY

UP SOLAR RAD ABV CNPY

SURF PRESS

WATER TABLE HGT

WATER OUTFLOW WEST

WATER OUTFLOW EAST

CRTFCN CODE

REVISION DATE

The sensible heat flux measured above the canopy.

The latent heat flux measured above the canopy.

The net radiation measured above the canopy.

The surface soil heat flux.

The carbon dioxide flux measured above the

canopy.

The incoming photosynthetically active radiation

measured above the canopy.

The reflected (outgoing) photosynthetically

active radiation measured above the canopy.

The incoming photosynthetically active radiation

measured under water.

The wind direction measured at 2 meters above the

reference surface.

The wind speed measured at 1 meter above the

reference surface.

The air temperature measured at 1 meter above

the reference surface.

The vapor pressure measured above the canopy.

The amount of rainfall measured above the canopy

in the 30 minute period following the given time.

The downward (incoming) solar radiation measured

above the canopy.

The reflected (outgoing) solar radiation measured

above the canopy.

The atmospheric pressure measured at the station.

Water table height above a reference surface.

The volume of water leaving the pond from the

western drainage.

The volume of water leaving the pond from the

eastern drainage.

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

DATE OBS

TIME OBS

SENSIBLE HEAT FLUX ABV CNPY

LATENT HEAT FLUX ABV CNPY

NET RAD ABV CNPY

SOIL HEAT FLUX

CO2 FLUX ABV CNPY

DOWN PAR ABV CNPY

UP PAR ABV CNPY

[none]

[none]

[DD-MON-YY]

[HHMM GMT]

[Watts] [meter^-2]

[Watts] [meter^-2]

[Watts] [meter^-2]

[Watts] [meter^-2]

[micromoles] [meter^-2] [second^-l]

[watts] [meter^-2]

[watts] [meter^-2]

Page 9
DOWN PAR UNDER WATER

WIND DIR 200CM

WIND SPEED 100CM

AIR TEMP 100CM

VAPOR PRESS ABV CNPY

RAINFALL

DOWN SOLAR RAD ABV CNPY

UP SOLAR RAD ABV CNPY

SURF PRESS

WATER TABLE HGT

WATER OUTFLOW WEST

WATER OUTFLOW EAST

CRTFCN CODE

REVISION DATE

[watts] [meter^-2]

[degrees from North]

[meters] [second^-l]

[degrees Celsius]

[kiloPascals]

[millimeters]

[Watts] [meter^-2]

[Watts] [meter^-2]

[kiloPascals]

[millimeters]

[meters^3] [second^-l]

[meters^3] [second^-l]

[none]

[DD-MON-YY]

7.3.4 Data Source

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

Column Name Data Source

SITE NAME

SUB SITE

DATE OBS

TIME OBS

SENSIBLE HEAT FLUX ABV CNPY

LATENT HEAT FLUX ABV CNPY

NET RAD ABV CNPY

SOIL HEAT FLUX

CO2 FLUX ABV CNPY

DOWN PAR ABV CNPY

UP PAR ABV CNPY

DOWN PAR UNDER WATER

WIND DIR 200CM

WIND SPEED 100CM

AIR TEMP 100CM

VAPOR PRESS ABV CNPY

RAINFALL

DOWN SOLAR RAD ABV CNPY

UP SOLAR RAD ABV CNPY

SURF PRESS

WATER TABLE HGT

WATER OUTFLOW WEST

WATER OUTFLOW EAST

CRTFCN CODE

REVISION DATE

[Assigned by BORIS.]

[Assigned by BORIS.]

[Supplied by Investigator.]

[Supplied by Investigator.]

[Supplied by Investigator.]

[Supplied by Investigator.]

[Net radiometer]

[Supplied by Investigator.]

[Infrared Gas Analyzer]

[quantum sensor]

[quantum sensor]

[quantum sensor]

[windvane]

[anemometer]

[Thermocouple]

[wet/dry thermocouples]

[tipping bucket rain gauge]

[Pyranometer]

[Pyranometer]

[barometer]

[Potentiometer]

[Supplied by Investigator.]

[Supplied by Investigator.]

[Assigned by BORIS.]

[Assigned by BORIS.]

Page 10
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

SUB SITE

DATE OBS

TIME OBS

SENSIBLE HEAT FLUX

ABV CNPY

NSA-BVP-FLXTR

TGB04-FLX01

28-MAY-94

0

-643 31

LATENT HEAT FLUX ABV -868 65

CNPY

NET RAD ABV CNPY -137 6

SOIL HEAT FLUX -498 83

CO2 FLUX ABV CNPY -25

DOWN PAR ABV CNPY 0

UP PAR ABV CNPY 0

DOWN PAR UNDER WATER 0

WIND DIR 200CM 0

WIND SPEED 100CM .2

AIR TEMP 100CM -2.32

VAPOR PRESS ABV CNPY .5

RAINFALL 0

DOWN SOLAR RAD ABV 0

CNPY

UP SOLAR RAD ABV 0

CNPY

SURF PRESS 97.7

WATER TABLE HGT -2.495

WATER OUTFLOW WEST 0

WATER OUTFLOW EAST 0

CRTFCN CODE CPI

REVISION DATE 17-MAR-99

NSA-BVP-FLXTR None None None None

TGB04-FLX01 None None None None

17-SEP-94 None None None None

2330 None None None None

832.66 -999 None None None

824.41 -999 None None None

769

1035.11

23.4224

412.1

26.68

71.2

359.5

5.98

28.67

3.15

129 84

959

107 5

i01 7

1.362

2932.243

.03

CPI

17-MAR-99

-999 None None None

-999 None None None

-999 None None Blank

-999 None None None

-999 None None None

-999 None None None

-999 None None None

-999 None None None

-999 None None None

-999 None None None

-999 None None Blank

-999 None None None

-999 None None None

-999 None None None

-999 None None Blank

-999 None None Blank

-999 None None Blank

None None None None

None None None None

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

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

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

indicate that an attempt was made to determine the

parameter value, but the attempt was unsuccessful.

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

to indicate an attempt was made to determine the

parameter value, but the value was deemed to be

unreliable by the analysis personnel.

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

instruments detection limits. This is used to

indicate that an attempt was made to determine the

parameter value, but the analysis personnel determined

that the parameter value was below the detection

limit of the instrumentation.

Page 11
Data Not Cllctd This value indicates that no attempt was made to

determine the parameter value. This usually

indicates that BORIS combined several similar but

not identical data sets into the same data base table

but this particular science team did not

measure that parameter.

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

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

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

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,DATE OBS,TIME OBS,SENSIBLE HEAT FLUX ABV CNPY,

LATENT HEAT FLUX ABV CNPY,NET RAD ABV CNPY, SOIL HEAT FLUX,CO2 FLUX ABV CNPY,

DOWN PAR ABV CNPY,UP PAR ABV CNPY,DOWN PAR UNDER WATER, WIND DIR 200CM,

WIND SPEED 100CM, AIR TEMP 100CM, VAPOR PRESS ABV CNPY,RAINFALL,

DOWN SOLAR RAD ABV CNPY,UP SOLAR RAD ABV CNPY, SURF PRESS,WATER TABLE HGT,

WATER OUTFLOW WEST,WATER OUTFLOW EAST,CRTFCN CODE,REVISION DATE

'NSA-BVP-FLXTR', 'TGB04-FLX01',28-MAY-94,2200,-6.73,102.54,269.3,173.49,1.8638,

170.1,13.31,23.02,134.3,3.32,24.28,.88,-999.0,359.3,33.13,98.9,1.281,-999.0,

-999.0, 'CPI',I7-MAR-99

'NSA-BVP-FLXTR', 'TGB04-FLX01',28-MAY-94,2230,-II.54,177.5,257.2,91.24,3.1192,

162.8,12.81,22.13,152.5,3.7,24.7,.87,-999.0, 347.6,31.97,98.9,1.281,-999.0,

-999.0, 'CPI',I7-MAR-99

'NSA-BVP-FLXTR', 'TGB04-FLX01',28-MAY-94,2300,-17.85,260.95,252.1,9.0,2.4295,

157.8,11.83,21.7,141.4,3.92,24.5,.85,-999.0,342.8,29.13,98.8,1.281,-999.0,

-999.0, 'CPI',I7-MAR-99

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.

Page 12
9. Data Manipulations

9.1 Formulae

9.1.1 Derivation Techniques and Algorithms

The calculation of fluxes required later computer calculation based upon measured momentum flux.

Wind speed profiles determine the momentum flux toward the surface and the associated transfer

coefficient Km is calculated and corrected for stability by temperature profile measurements. Using

similarity theory, the same transfer coefficient is applied to the fluxes of sensible and latent heat, and

CO2 using the formula of the form:

Flux = K x dA/dz

where K is the eddy diffusivity or transfer coefficient, and the second term is the gradient of the entity

concerned. A good review of the procedures used is found within Oke (1987), Appendix A2, Section

2b. Given the calculations of sensible and latent heat and measured net, incoming, and outgoing

radiation, this allows closure of the energy and surface balance equations by attributing the difference

to the ground heat flux (Qg).

9.2 Data Processing Sequence

9.2.1 Processing Steps

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.

9.2.2 Processing Changes

None.

9.3 Calculations

9.3.1 Special Corrections/Adjustments

None.

9.3.2 Calculated Variables

The CO 2 flUX and the latent, sensible, and soil heat fluxes were calculated.

9.4 Graphs and Plots

None.

Page 13
10. Errors

10.1 Sources of Error

Instrument error could occur due to wire disconnection or shorting, multiplexer or data logger

malfunction, or battery or generator failure. In addition, due to the elaborate nature of calculating

fluxes based upon profile measurements, certain theoretical errors can become large in some situations.

These situations occur mainly at dusk and overnight when wind speeds become very small and

differences in wind speed become negligible over such a short tower. In these cases, the eddy

diffusivity can become zero, resulting in a zero flux value. Under these circumstances, our methods

would suggest there are no fluxes either up or down, although they must be occurring, but below the

sensitivity of ordinary profile system anemometry. In addition, very small gradients of any parameter

approaching the limitations of the instrument could also result in an underestimate of the actual existing

flux by reducing the gradient to something approaching zero. This may seem important; however,

these times occur infrequently, and the fluxes must be quite small. In any case, over a diurnal period

the errors associated with the profile technique are not thought to be a significant missing component

of the energy or CO2 balance.

10.2 Quality Assessment

10.2.1 Data Validation by Source

All data were plotted and checked to determine if there were any outlying points that were

obviously incorrect. These points were removed and replaced by -999, which was used to indicate

missing or bad values within the data set submitted.

10.2.2 Confidence Level/Accuracy Judgment

The confidence level of this data set is high, since the submitted data have been visually checked

for inconsistencies. Perhaps the greatest potential error is associated with the ground heat flux (Qg),

which is obtained by residual. This same system has been used successfully in previous experiments at

the Experimental Lakes Area, in northwest Ontario.

10.2.3 Measurement Error for Parameters

Energy balance terms are thought to be within 10% when calculated, and certainly less than that

when measured directly, the error in this case is discussed in Section 5.2.1. As discussed above,

ground heat flux error could be larger since it is calculated by residual from all other energy budget

terms.

10.2.4 Additional Quality Assessments

Since the calculated surface energy budget and CO 2 flUX is based upon the calculation of an

accurate momentum flux or eddy diffusivity value (K), a test was initiated toward the end of the

campaign to test this calculated variable. In addition to the profile measurements of wind speed, a sonic

anemometer was placed on the tower and the momentum coefficient was calculated using this

instrument. Over the 4 days of overlapping measurement, differences between systems were not

significant, and no corrections due to over- or underestimation were suggested.

10.2.5 Data Verification by Data Center

Data were examined to check for spikes, values that are four standard deviations from the mean,

long periods of constant values, and missing data.

Page 14
11. Notes

11.1 Limitations of the Data

See Section 10.1.

11.2 Known Problems with the Data

There were no known problems with the submitted data.

11.3 Usage Guidance

None required.

11.4 Other Relevant Information

Beavers were frequently sighted, and seemed completely undisturbed by our tower in the center of

their pond. In fact, they seemed quite inquisitive and were often seen passing near the tower platform.

There was one bear sighting at the pond edge, even with the nearby noisy generator. Fauna

environmental impact was therefore negligible.

12. Application of the Data Set

These data are useful for the study of water, energy, and carbon exchange in a beaver pond.

None.

13. Future Modifications and Plans

14.1 Software Description

None given.

14.2 Software Access

None given.

14. Software

15. Data Access

The NSA-BVP tower flux and meteorological 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@ornl.gov or ornl@eos.nasa.gov

Page 15
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.oml.gov/] and the anonymous FTP site [ftp://www-eosdis.oml.gov/data/] or by

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

information in Section 15.1.

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

Campbell Scientific Corporation CR7 Manual LI-COR 6252 Gas Analyzer Manual

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.

Oke, T.R. 1987. Boundary layer climates. Routledge, Second Edition, New York, 435p.

Roulet, N.T., N. Comer, A. Dove, J. Etchevery, C. Robinson, S. Glenn, and P. Crill. (date

unknown). Missing carbon sinks, beaver ponds, and the boreal carbon budget. Centre for Climate and

Global Change Newsletter, 6(1): 5-8.

Roulet, N.T., P.M. Crill, N.T. Comer, A.E. Dove, and R.A. Boubonniere. 1997. CO2 and CH4 flux

between a boreal beaver pond and the atmosphere. Journal of Geophysical Research 102(D24):

29,313-29,319.

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

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

Page 16
Sellers,P.andF.Hall. 1996.BorealEcosystem-AtmosphereStudy:ExperimentPlan.Version

1996-2.0,NASA BOREASReport(EXPLAN 96).

Sellers,P.,F. Hall, andK.F. Huemmrich.1996.BorealEcosystem-AtmosphereStudy:1994

Operations.NASA BOREASReport(OPSDOC94).

Sellers,P.,F. Hall, andK.F. Huemmrich.1997.BorealEcosystem-AtmosphereStudy:1996

Operations.NASA BOREASReport(OPSDOC96).

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.

17.3 Arehive/DBMS Usage Documentation

None.

None.

18. Glossary of Terms

A/D

ASCII

BOREAS

BORIS

BVP

CD-ROM

DAAC

DOC

EC

EOS

EOSDIS

GIS

GMT

GSFC

HTML

IRGA

NAD83

NASA

NSA

ORNL

PANP

PAR

PC

19. List of Acronyms

- Analog to Digital

- American Standard Code for Information Interchange

- BOReal Ecosystem-Atmosphere Study

- BOREAS Information System

- Beaver Pond

- Compact Disk-Read-Only Memory

- Distributed Active Archive Center

- Dissolved Organic Carbon

- Eddy Covariance

- Earth Observing System

- EOS Data and Information System

- Geographic Information System

- Greenwich Mean Time

- Goddard Space Flight Center

- HyperText Markup Language

- Infrared Gas Analyzer

- North American Datum of 1983

- National Aeronautics and Space Administration

- Northern Study Area

- Oak Ridge National Laboratory

- Prince Albert National Park

- Photosynthetically Active Radiation

- Personal Computer

Page 17
PPFD

REBS

SSA

TF

TGB

URL

WAB

WMO

- Photosynthetic Photon Flux Density

- Radiation Energy Balance Systems

- Southern Study Area

- Tower Flux

- Trace Gas Biogeochemistry

- Uniform Resource Locator

- Wind Aligned Blob

- World Meteorological Organization

20. Document Information

20.1 Document Revision Date

Written: 22-May- 1995

Revised: 12-Sep- 1999

20.2 Document Review Date(s)

BORIS Review: 08-Apr- 1999

Science Review:

20.3 Document ID

20.4 Citation

When using these data, please acknowledge N. Roulet and his team and include citations of

relevant papers in Section 17.2.

When using these data please acknowledge N. Roulet and his team.

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

Roulet, N.T., "The Fluxes of Energy and Trace Gases from Beaver Ponds and Dry Upland Forest

Floor in the NSA." 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 18
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

November 2000 Technical Memorandum

4. TITLE AND SUBTITLE 5. FUNDING NUMBERS

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

BOREAS TGB-4 NSA-BVP Tower Flux and Meteorological Data 923

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

Nigel T. Roulet

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. 227

11. SUPPLEMENTARY NOTES

N.T. Roulet: McGill University, Montreal, Quebec;

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 TGB-4 team measured the exchange of heat, water, and CO 2 between a boreal forest

beaver pond and the atmosphere in the NSA for the ice-free period of BOREAS. The data cover the

period of 28-May to 18-Sep-1994. The data are available in tabular ASCII files.

14. SUBJECT TERMS

BOREAS, trace gas biogeochemistry.

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

18

16. PRICE CODE

20. LIMITATION OF ABSTRACT

UL

Standard Form 298 (Rev. 2-89)

Prescribed by ANSI Std. Z39.18

298-102