BOREAS AFM-02 King Air 1994 Aircraft Flux and Moving Window Data

Summary:

The BOREAS AFM-02 team collected pass-by-pass fluxes (and many other
statistics) for a large number of level (constant altitude), straight
line passes used in a variety of flight patterns. The data were
collected by the University of Wyoming King Air in 1994 BOREAS IFCs 1-3.
Most of these data were collected at 60-70 m above ground level, but a
significant number of passes were also flown at various levels in the
planetary boundary layer, up to about the inversion height. This
documentation concerns only the data from the straight and level passes
that are presented as original samples and moving window values. Another
archive of King Air data is also available, containing data from all the
soundings flown by the King Air 1994 IFCs 1-3.

Note that although there are less than 100 records in any data file,
there are over 170 columns of data. Most spreadsheet software should be
able to handle up to 256 columns of data.

Table of Contents

\* 1 Data Set Overview

\* 2 Investigator(s)

\* 3 Theory of Measurements

\* 4 Equipment

\* 5 Data Acquisition Methods

\* 6 Observations

\* 7 Data Description

\* 8 Data Organization

\* 9 Data Manipulations

\* 10 Errors

\* 11 Notes

\* 12 Application of the Data Set

\* 13 Future Modifications and Plans

\* 14 Software

\* 15 Data Access

\* 16 Output Products and Availability

\* 17 References

\* 18 Glossary of Terms

\* 19 List of Acronyms

\* 20 Document Information

1\. Data Set Overview

1.1 Data Set Identification

BOREAS AFM-02 King Air 1994 Aircraft Flux and Moving Window Data

1.2 Data Set Introduction

The King Air was flown in a variety of flight patterns in BOREAS-94, but
predominantly in various sequences of straight, constant-altitude passes
for measurement of fluxes and flux profiles in the boundary layer above
the BOREAS experiment sites. This document describes the contents of
these \"flux\" archives, which also include statistical summaries of a
large number of navigational, dynamic, and thermodynamic parameters.

1.3 Objective/Purpose

The Wyoming King Air is one of four flux aircraft flown in BOREAS. The
primary objectives of its operation were to measure fluxes of sensible
heat, latent heat (moisture), momentum, and carbon dioxide in the
boundary layer. In addition, atmospheric dynamic, thermodynamic, and
radiation data were collected, along with the standard aircraft
parameters of position, altitude, heading, etc. These data will be used
for estimates of surface fluxes, boundary layer budgets, error analysis
of flux measurements, and will be integrated with smaller and larger
scale measurements from the project.

1.4 Summary of Parameters

The following is a list of variables for each \"flux pass\" by the King
Air. Section 7 defines the variables and their origins in detail. The
moving window data values represent averages over 180-second measurement
periods with each period overlapping the period before and the period
after by 90 seconds. With the average King Air airspeed being 85-90 m/s,
the segments will have an average length of 15.3 to 16.2 km. Note: Those
variables flagged (\*\*) were not measured by the King Air.

VARIABLES:

BOREAS aircraft i.d.

Date

BOREAS mission designator

Mission number of day

Pass number

Segment number

Run start time, GMT

Starting latitude

Starting longitude

Starting BORIS grid E

Starting BORIS grid N

Run end time, GMT

Ending latitude

Ending longitude

Ending BORIS grid E

Ending BORIS grid N

Aircraft heading

Mean pressure altitude

Mean radar altitude

Mean wind direction

Mean wind speed

Air temperature

Potential temperature

Mixing ratio, H~2~0

U, westerly wind component

V, southerly wind component

Static pressure

Surface radiative temperature \*\*

Downwelling total radiation

Upwelling total radiation

Downwelling longwave radiation

Upwelling longwave radiation

Net radiation \*\*

Upwelling PAR \*\*

Downwelling PAR \*\*

Auxiliary radiation sensor \*\*

Greenness index \*\*

CO~2~ concentration as mole CO~2~ per mole dry air (also referred to as
CO~2~ molar mixing ratio. If it were given as just CO~2~ mixing ratio,
the units would be mass CO~2~ per mass dry air).

Ozone concentration \*\*

Methane concentration \*\*

Satellite simulator channels 1-4 \*\*

Standard deviations of the following:

Air temperature

Potential temperature

Mixing ratio, H~2~0

U, westerly wind component

V, southerly wind component

Static pressure

Surface radiative temperature \*\*

Downwelling total radiation

Upwelling total radiation

Downwelling longwave radiation

Upwelling longwave radiation

Net radiation \*\*

Upwelling PAR \*\*

Downwelling PAR \*\*

Auxiliary radiation sensor \*\*

Greenness index \*\*

CO~2~ concentration (mole CO~2~ per mole dry air)

Ozone concentration \*\*

Methane concentration \*\*

Satellite simulator, channels 1-4 \*\*

Linear trends of the following:

Trend in air temp.

Trend in potential temp.

Trend in mixing ratio

Trend in u

Trend in v

Trend in static pressure

Trend in surface radiation temperature \*\*

Trend in downwelling total radiation \*\*

Trend in upwelling total radiation \*\*

Trend in downwelling longwave radiation \*\*

Trend in upwelling longwave radiation \*\*

Trend in greenness index \*\*

Trend in CO~2~ concentration

Trend in O~3~ concentration \*\*

Trend in CH~4~ concentration \*\*

In various categories to follow, the following variables are referred to
as the flux variables:

Vertical gust, w

Westerly wind component, u

Southerly wind component, v

Along wind component

Crosswind component

Potential temperature

H~2~0 mixing ratio (mass H~2~O per mass dry air)

CO~2~ mixing ratio (mass CO~2~ per mass dry air)

O~3~ concentration \*\*

CH~4~ concentration \*\*

In various categories to follow, these variable pairs are referred to as
the flux variable pairs:

w, u

w, v

w, alongwind comp.

w, crosswind comp.

w, potential temp

w, H~2~O mixing ratio (mass H~2~O per mass dry air)

w, CO~2~ mixing ratio (mass CO~2~ per mass dry air)

w, O~3~ concentration \*\*

w, CH~4~ concentration \*\*

Potential temperature, H~2~O mixing ratio

List of fluxes:

Momentum flux, south component

Momentum flux, west component

Momentum flux along mean wind

Momentum flux across

Sensible heat flux, H

Latent heat flux, LE

CO~2~ flux

Ozone flux \*\*

Ozone deposition velocity \*\*

Methane flux \*\*

Standard deviations for the raw flux variables

Skewness for the raw flux variables

Kurtosis for the raw flux variables

Correlation coefficients for the raw flux variable pairs

Fluxes using the raw data

Constants used in the flux calculations (such as specific heats, latent
heat)

Standard deviations for the linearly detrended flux variables

Skewness for the linearly detrended flux variables

Kurtosis for the linearly detrended flux variables

Correlation coefficients for the linearly detrended flux variable pairs

Fluxes using the linearly detrended data

1.5 Discussion

The King Air was flown in all three IFCs in BOREAS-1994. The archived
data were collected during straight and level flight lines over the
BOREAS Study Areas and on regional runs between Southern Study Area
(SSA) and Northern Study Area (NSA). A variety of flight patterns were
used, including grids, L- patterns, profiling stacks, and soundings,
which are described in more detail in Section 7. Two separate sets of
data have been submitted to the BORIS archive: 1-second resolution
listings of various variables from the soundings, and fluxes and
statistics from the level flux runs. Variables in the latter category
include pass-length averages and other statistics, momentum and scalar
fluxes, and supporting meteorological, radiometric and aircraft
positional data. The high-rate data from which all these variables were
computed were not submitted to BORIS. If required, they may be acquired
from the University of Wyoming directly.

1.6 Related Data Sets

Related data sets include the King Air sounding data for BOREAS-94 and
the flux and/or sounding archives from the other three flux aircraft:

BOREAS AFM-01 Moving Window Aircraft Flux Data

BOREAS AFM-02 Aircraft Sounding Data

BOREAS AFM-03 Aircraft Flux and Moving Window Data

BOREAS AFM-03 Aircraft Sounding Data

BOREAS AFM-04 Aircraft Flux Data

BOREAS AFM-04 Aircraft Sounding Data

2\. Investigator(s)

2.1 Investigator(s) Name and Title

Dr. Robert D. Kelly, Associate Professor

University of Wyoming

Laramie, WY

2.2 Title of Investigation

Airborne Investigation of Biosphere-Atmosphere Interactions over the
Boreal Forest.

2.3 Contact Information

Contact 1

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

Robert D. Kelly

University of Wyoming

Laramie, WY

\(307\) 766-4955

\(307\) 766-2635 (fax)

HREF=\"

Contact 1

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

Jeffrey Newcomer

Raytheon ITSS

NASA/GSFC

Greenbelt, MD

(301)286-7858

(301)286-0239 (fax)

Jeffrey.Newcomer@gsfc.nasa.gov

3\. Theory of Measurements

A series of introductory monographs addressing the theory and practice
of measuring atmospheric variables from a moving, aircraft platform may
be found in (Lenschow, D. H., ed., 1986: Probing the Atmospheric
Boundary Layer, Amer. Meteor. Soc., Boston). An introduction to the
general topic of eddy correlation fluxes may be found in (Stull, R. B.,
1988: An Introduction to Boundary Layer Meteorology, Kluwer Acad. Pub.,
Boston).

The aircraft uses gust sensors to measure the 3-D air motion relative to
the aircraft and a combination of an inertial platform, accelerometers,
and (more recently) satellite-based global positioning system (GPS) to
measure the motion of the aircraft relative to the earth. These data are
combined to determine aircraft position and the earth-relative 3-D
winds. Scalar quantities, including static pressure, temperature, water
vapor mixing ratio, and CO~2~ mixing ratio are also measured with
fast-response, aircraft-mounted sensors. For each straight, level pass
by the aircraft the local means or trends are removed from each of the
wind components and the scalar values, leaving the gust components u\',
v\', w\', T\', r\', etc. with which the eddy correlation fluxes are
calculated.

4\. Equipment:

4.1 Sensor/Instrument Description

Table of University of Wyoming King Air Instruments

+-----------------+------------------+--------------+-----------------+
| Variable        | Instrument       | Accuracy     | Resolution      |
+-----------------+------------------+--------------+-----------------+
| Hi-rate         | Rosemount        | 0.50 C       | 0.01 C          |
| temperature     | housing with     |              |                 |
|                 | fast-response    |              |                 |
|                 | thermistor       |              |                 |
|                 | (design by       |              |                 |
|                 | Friehe, UCI)     |              |                 |
+-----------------+------------------+--------------+-----------------+
| Dewpoint        | Cambridge Model  | 1.0 C, \>0 C | 0.006 C         |
| temperature     | 1373C            |              |                 |
+-----------------+------------------+--------------+-----------------+
| Water vapor mix | LICOR 6262 IR    | 1% of        | 0.001 g/kg      |
| ratio           | spectrometer     | reading      |                 |
+-----------------+------------------+--------------+-----------------+
| CO~2~ mix ratio | LICOR 6262 IR    | +/-1ppm at   | 350 ppm         |
|                 | spectrometer     | .01 ppm      |                 |
+-----------------+------------------+--------------+-----------------+
| Magnetic        | King             | 1 degree     | 0.02 degree     |
| heading         | KPI553/Sperry    |              |                 |
|                 | C14-43           |              |                 |
+-----------------+------------------+--------------+-----------------+
| Static pressure | Rosemount        | 0.5 mb       | 0.06 mb         |
|                 | 1201FA1B1A       |              |                 |
+-----------------+------------------+--------------+-----------------+
| Static pressure | Rosemount 1501   | 0.5 mb       | 0.003 mb        |
+-----------------+------------------+--------------+-----------------+
| Geometric       | Stewart Warner   | 1% reading   | 0.24 ft         |
| Altitude        | APN159           |              |                 |
+-----------------+------------------+--------------+-----------------+
| Geometric       | King KPA 405     | 3% \<500 ft  | 0.48 ft         |
| Altitude        |                  |              |                 |
|                 |                  | 6% \> 500 ft |                 |
+-----------------+------------------+--------------+-----------------+
| Total pressure  | Rosemount 831CPX | 2 mb         | 0.005 mb        |
+-----------------+------------------+--------------+-----------------+
| Azimuth VOR     | King KNR615 VOR  | 1 degree     | 0.02 degree     |
+-----------------+------------------+--------------+-----------------+
| Distance DME    | King KNR705A DME | 0.2 nautical | 0.1 nautical    |
|                 |                  | miles        | mile            |
+-----------------+------------------+--------------+-----------------+
| Lati            | Tremble 2000 GPS | 100 m        | 0.000172 degree |
| tude/longtitude |                  |              |                 |
+-----------------+------------------+--------------+-----------------+
| Lati            | Honeywell        | 0.8 nm/hr    | 0.000172 degree |
| tude/longtitude | Laseref SM       | drift        |                 |
+-----------------+------------------+--------------+-----------------+
| Ground velocity | Honeywell        | 13.5 ft/s    | 0.0039 kts      |
|                 | Laseref SM       |              |                 |
+-----------------+------------------+--------------+-----------------+
| Vertical        | Honeywell        | 0.5 ft/s     | 0.03215 ft/min  |
| velocity        | Laseref SM       |              |                 |
+-----------------+------------------+--------------+-----------------+
| Pitch/roll      | Honeywell        | 0.05 degree  | 0.000172 degree |
|                 | Laseref SM       |              |                 |
+-----------------+------------------+--------------+-----------------+
| Platform        | Honeywell        | 0.2 degree   | 0.000172 degree |
| heading         | Laseref SM       |              |                 |
+-----------------+------------------+--------------+-----------------+
| Flow angle      | Rosemount        | 0.2 degree   | 0.00375 degree  |
|                 | 858AJ/831CPX     |              |                 |
+-----------------+------------------+--------------+-----------------+
| Vertical        | Humphrey         | 0.002 g      | 0.0001 g        |
| acceleration    | SA0905021        |              |                 |
+-----------------+------------------+--------------+-----------------+
| Rate of climb   | Rosemount        | 1%, \<15000  | 0.004 m/s       |
|                 | 1241A4BCDE       | ft           |                 |
|                 |                  |              |                 |
|                 |                  | 2%, \>25000  |                 |
|                 |                  | ft           |                 |
+-----------------+------------------+--------------+-----------------+
| Engine torque   |                  | \-\--        | 0.2 ft-lbf      |
+-----------------+------------------+--------------+-----------------+
| Liquid Water    | In-house CSIRO   | 0.2 g/m^3^   | 0.0003 g/m^3^   |
| Content         | hot wire         |              |                 |
+-----------------+------------------+--------------+-----------------+
| Liquid Water    | Bacharach LWH    | 0.2 g/m^3^   | 0.0002 g/m^3^   |
| Content         |                  |              |                 |
+-----------------+------------------+--------------+-----------------+
| Cloud drops     | PMS FSSP         | 3 micron     | 3 micron        |
+-----------------+------------------+--------------+-----------------+
| Radiation:      |                  |              |                 |
+-----------------+------------------+--------------+-----------------+
| Upwelling       | Eppley           | 5 W/m^2^     | 1 W/m^2^        |
| Shortwave       | Pyranometer      |              |                 |
|                 |                  |              |                 |
| (0.3-3 microns) |                  |              |                 |
+-----------------+------------------+--------------+-----------------+
| Downwelling     | Eppley           | 5 W/m^2^     | 1 W/m^2^        |
| Shortwave       | Pyranometer      |              |                 |
|                 |                  |              |                 |
| (0.3-3 microns) |                  |              |                 |
+-----------------+------------------+--------------+-----------------+
| Upwelling IR    | Eppley           | 15 W/m^2^    | 1 W/m^2^        |
|                 | Pyrgeometer      |              |                 |
| (4-50 microns)  |                  |              |                 |
+-----------------+------------------+--------------+-----------------+
| Downwelling IR  | Eppley           | 15 W/m^2^    | 1 W/m^2^        |
|                 | Pyrgeometer      |              |                 |
| (4-50 microns)  |                  |              |                 |
+-----------------+------------------+--------------+-----------------+

4.1.1 Collection Environment

4.1.2 Source/Platform

Platform: Beechcraft Super King Air model 200T, twin-turboprop aircraft

4.1.3 Source/Platform Mission Objectives

See section 1.4

4.1.4 Key Variables

See sections 1.4, 1.5, 7.3

4.1.5 Principles of Operation

See section 3.

4.1.6 Sensor/Instrument Measurement Geometry

The gust probe was mounted at end of aircraft nose boom, so that the
gust probe tip was about 2 m ahead of the nose of the aircraft. Inertial
platform (IRS) and accelerometers were mounted close to the main wing
spar (close to aircraft c.g.). Fast-response (Friehe-type) Temperature
probe mounted below nose of aircraft, 1.29 m aft from the gust probe
tip. Water vapor and CO~2~ measurements obtained with LICOR 6262
infrared absorption spectrometer. Air drawn from airstream above
aircraft cabin into 12.7-mm i.d. tube which faces forward, about 0.3 m
above the fuselage skin and 4.06 m aft of the gust probe tip. Airflow in
the tube maintained with high-capacity vacuum pump at 60-70 SLPM (about
9 m/s), for Reynolds number about 50,000 (fully developed turbulent
flow). At 1.52 m from the inlet, air is drawn from the center of the
tube into the LICOR trough a short 6.4-mm i.d. tube, again by vacuum
pump, at average flow rate of 6-8 SLPM (also fully turbulent). As
verified by flying the aircraft through a power-plant plume, there is a
time delay of 0.3 s between the gust probe data and the LICOR data. This
delay is removed in the software at the time of data processing. The
LICOR 6262 was operated in absolute mode, in which the closed-path
absorption in the sample chamber was simultaneously compared to the
closed-path absorption in the reference chamber. Air in the reference
chamber was circulated continuously through scrubbers that remove both
water and CO~2~, and was circulated at a flow rate of 2 SLPM. Cambridge
chilled-mirror dew-point hygrometer mounted inside cabin drew air from
vacuum pump driven sample tube. All cloud and precipitation probes (PMS
and liquid water content) were mounted near wing tips, both wings.

4.1.7 Manufacturer of Sensor/Instrument

See table in section 4.1

4.2 Calibration

Instruments subject to calibration as follows:

Air temperature: Used manufacturer\'s one-time calibration for Rosemount
model 102, then compared Friehe-type probe against Rosemount.

Water vapor concentration: Before each flight, the LICOR H~2~O channel
was calibrated by flushing the chamber with a beam-filling gas of known
H~2~O concentration, generated with a LI-COR Model 610 Dew-Point
generator, with accuracy +/-0.03 C.

CO~2~ concentration: Before each flight, the LICOR CO~2~ channel was
calibrated by flushing the chamber with a gas of known CO~2~
concentration (Source: Scott Specialty, Longmont, Colo., concentration
403.5 ppm, accurate to 4%). Static pressure and gust differential
pressures: The gust probe differential pressure sensors (for up-down and
left-right angle of flow measurements) and absolute pressure sensor
(gust probe total pressure) were calibrated at the beginning of each
IFC, using the Rosemount 1501 (accurate to 0.5 mb).

4.2.1 Specifications

See table 4.1

4.2.1.1 Tolerance

None given.

4.2.2 Frequency of Calibration

See section 4.2

4.2.3 Other Calibration Information

None given.

5\. Data Acquisition Methods

The straight-line, constant altitude passes used for the flux
calculations were all parts of several different flight patterns uses
throughout BOREAS-94. What follows here is a brief description of those
patterns, including the short, two-letter identifier used for
communications, labeling data files, etc.

ID Description (second letter denotes NSA or SSA)

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

CS Candle Lake runs, SSA only, usually along path a-d.

FS,FN Flights of two (intercomparison runs), various locations.

GS,GN Grid patterns. Sequence of 9 evenly spaced, parallel flight lines,

covering a 32x32 km square area (King Air), with lines oriented either

east-west or north-south.

HS,HN Stack patterns

LS,LN Transects of intermediate length (e.g. 100 km).

PS,PN Budget box pattern (see Betts et al., 1990, Boundary Layer
Meteorology,

50, 109-137.

RT Regional transect. For King Air, route used in transit between NSA
and SSA. Coincide with Electra RTs.

TS,TN Site-specific run at a TF (tower flux) site.

Navigation waypoints used for flying the patterns:

Pt. Lat. Long.

A 53° 32.0\' -106° 34.0\'

C 53° 37.8\' -106° 11.4\' (same as PANP-OA)

G 53° 55.6\' -104° 59.7\'

H 54° 07.0\' -104° 13.5\'

K 54° 41.7\' -103° 47.5\'

L 54° 57.3\' -101° 58.0\'

M 55° 54.8\' -99° 07.5\'

O 55° 53.2\' -98° 00.0\'

P 60° 30.0\' -98° 00.0\'

Q 60° 30.0\' -95° 30.0\'

R 59° 00.0\' -95° 30.0\'

CH 58° 44.5\' -94° 04.0\' (Churchill airport)

a 53° 34.7\' -106° 23.8\'

b 53° 42.8\' -105° 52.0\'

c 53° 55.0\' -105° 04.0\'

d 53° 59.0\' -104° 47.2\'

f 53° 59.8\' -104° 43.5\'

g 53° 32.0\' -104° 27.6\'

h 53° 56.8\' -105° 20.5\'

i 54° 03.7\' -104° 45.5\'

j 53° 43.8\' -104° 34.0\'

k 53° 35.8\' -106° 18.0\'

m 54° 05.2\' -104° 50.5\'

n 53° 32.2\' -104° 19.5\'

s 53° 17.0\' -105° 43.0\'

t 53° 38.0\' -105° 43.0\'

u 53° 17.0\' -105° 32.0\'

v 53° 43.0\' -105° 17.0\'

Centers of north and south KA grids:

North 55° 52.5\' -98° 31.5\'

South 53° 51.5\' -104° 48.6\'

Other locations:

NOAA radar 55° 56.0\' -98° 36.8\'

6\. Observations

6.1 Data Notes

None given.

6.2 Field Notes

None given.

7\. Data Description

7.1 Spatial Characteristics

7.1.1 Spatial Coverage

The majority of the data were collected over the BOREAS SSA and NSA. The
North American Datum 1983 (NAD83) corner coordinates of the SSA are:

Latitude Longitude

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

Northwest 54.321° N 106.228 W

Northeast 54.225° N 104.237 W

Southwest 53.515° N 106.321 W

Southeast 53.420° N 104.368 W

The NAD83 corner coordinates of the NSA are:

Latitude Longitude

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

Northwest 56.249° N 98.825 W

Northeast 56.083° N 97.234 W

Southwest 55.542° N 99.045 W

Southeast 55.379° N 97.489 W

The actual spatial coverage of the data values is defined by the flight
pattern, leg length, etc. These values are contained in each archived
set of numbers for each pass or segment.

The moving window data values represent averages over 180-second
measurement periods with each period overlapping the period before and
the period after by 90 seconds. With the average King Air airspeed being
85-90 m/s, the segments will have an average length of 15.3 to 16.2 km.

7.1.2 Spatial Coverage Map

Not available.

7.1.3 Spatial Resolution

The fluxes and statistics archived here are for passes or segments of
passes between pre-defined waypoints, as part of various flight patterns
(see Section 5). The shortest times for such passes/segments are about 2
min, i.e., about 10 km. Thus, the spatial resolution is about 10 km or
greater. For the grid patterns (GS, GN) the passes are each 32 km in
length. The Candle Lake (CS) runs were divided into two segments, one
over the relatively homogeneous Old Aspen area surrounding the OA flux
tower (east end of CL run), and the other over the area at the west end
of the run dominated by black spruce. Each long leg of the regional
transects (RT) was segmented into 180-second segments, each overlapping
the adjoining two segments by 50%.

7.1.4 Projection

Not applicable.

7.1.5 Grid Description

Not applicable.

7.2 Temporal Characteristics

7.2.1 Temporal Coverage

Times of data collection contained in table to follow in this section.

Abbreviations used in weather notes in table:

cu cumulus

st status

ci cirrus

sct scattered

Zi inversion height above ground

H haze

K smoke

cist cirrostratus

clr clear

ovc overcast

RW- light rain showers

acu altocumulus

Abbreviations in flight descriptions:

rt round trip

agl above ground level (in feet)

msl above mean sea level (in feet)

mult multiple

TAS true airspeed

lvl level

wind \"L\" \"L\" with one leg parallel to wind direction, flown as at
least one round trip.

See section 5 for flight pattern descriptions.

Summary of UW King Air research flights for BOREAS 1994

Times(UT)

  -------- ------- ------ ------ --------------- ---------------------------
  Date     Start   End    Hrs    Weather         Description and comments

  940525   1745    2000   2.9    5-10% sct cu    CS, 2 rts a-h, 300 agl FS,
                                                 first a-h with FE

  940526   1646    1905   3.0    ci, small % cu  GS, full rt, 300 agl

  940531   1645    1929   3.6    cu incr 10-40%  FS, 300 agl with FT PS,
                                 sharp jump Zi   using W,E ends FK grid at
                                                 200 agl, 2500 and 3400 msl
                                                 FS, a-d, 300 agl, with FE

  940601   630     1802   2.4    H, ci, cist sct LS, j-i-h-i-j, 200 agl CS,
                                 cu \< 1%        one rt d-a-d, 200 agl

  940604   1616    1919   3.8    clr then cu     CS, mult passes 200 agl,
                                 incr rapidly,   3000 msl FS, d-a, 200 agl,
                                 end ovc         with FL

  940606   1546    1809   3.1    cu \< 5%        LS, mult h-i-j, 200
                                                 agl-2900 msl

  940607   1447    1649   4.8    clr entire      RT, a-h-k-l-m, 200 agl
                                 pattern         

           1649    1904          clr entire      GN, full rt, all 300 agl,
                                 pattern         EW lines

  940608   1520    1742   2.9    clr             LN, mult t-o at 200 agl,
                                                 2100 msl FN, m-o, 300 agl
                                                 with FT

  940610   1642    1901   3.0    sct ci, K all   GN, full rt, 200 agl, NS
                                 sky             lines

  940611   1646    1844   2.6    K, cu to 80%,   RT, o-m-l-k-h-a, 200 agl
                                 RW-             

  940720   1656    2044   4.4    H, K, cu 10-50% CS, a-d, 300 agl to 4800
                                                 msl (co-ord with FE) FS,
                                                 two a-d, 300 agl with FE

  940721   1652    1905   3.0    clr?            GS, full rt, 200 agl, NS
                                                 lines FS, one run SW of
                                                 grid with FT

  940723   1528    1800   3.2    clr, incr to    CS, mult a-d at 200 agl,
                                 20% cu          3500 msl

  940724   1655    1943   3.4    clr over site   GS, full rt, 200 agl, EW
                                                 lines

  940725   1519    1753   3.2    clr             CS, mult a-d at 200 agl,
                                                 3000 msl

  940726   1628    1832   2.7    K, ci           RT, a-h-k-l-m-o, 200 agl

  940727   1609    1909   4.3    K, altocu, cu   GN, full rt 200 agl, NS
                                                 lines TN (mult) at radar,
                                                 500-1000 agl

  940728   1620    1810   2.6    K, ci           HN(GN) time-centered m-o,
                                                 200 agl, 1800 and 2700 msl

  940731   1550    1859   3.7    K, clr above    GN

  940831   1720    1938   2.9    K, cu \<1 to    GN, full rt, 200 agl, EW
                                 40%             lines

  940901   1550    1717   1.9    clr above K     FN, rt 200 agl, with FT FN,
                                                 rt 200 agl, diff TAS than
                                                 FT LN, o-m-o-m-o, 200 agl

  940903   1548    1811   3.0    ci, K, cu 0-10% GN, full rt, 200 agl, EW
                                                 lines

  940906   1605    1833   2.9    cu 20-80%       GN, full rt, 200 agl, NS
                                                 lines

  940908   1606    1823   2.8    acu, ci, cist,  RT, o-m-l-k-h-a, 200 agl
                                 ci ovc          

  940909   1940    2131   2.7    ci, cist        CS, mult 200 agl-2600 msl,
                                 thinning        with FE FS, 300 agl, with
                                                 FE

  940912   1735    2004   3.6    cu incr 0-30%   CS, 3 rts, all 200 agl Test
                                                 = 3 rt over OA area of CS

  940913   1645    1905   3.4    clr, then cist  GS, full rt, 200 agl, EW
                                 and ci          lines Test = wind \"L\" at
                                                 8500 msl

  940916   1653    1914   4.8    clr             GS, full rt, NS lines, 200
                                                 agl

           1925    2053          clr then \<5%   CS, d-a mult lvls, with FE
                                 cu              FS, second a-d with FE, 600
                                                 agl

  940917   1712    1902   2.4    clr, thin ci to FS, one end=a, 200 agl,
                                 W               with FT CS, a-d, two rts,
                                                 200 agl
  -------- ------- ------ ------ --------------- ---------------------------

7.2.2 Temporal Coverage Map

See section 7.2.1

7.2.3 Temporal Resolution

See section 7.2.1. Also, each archived data entry contains the start and
end times for the pass/segment being summarized.

The moving window data values represent averages over 180-second
measurement periods with each period overlapping the period before and
the period after by 90 seconds. With the average King Air airspeed being
85-90 m/s, the segments will have an average length of 15.3 to 16.2 km.

7.3 Data Characteristics

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

7.4 Sample Data Record

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

8\. Data Organization

8.1 Data Granularity

The King Air data are in two files: one for unaveraged flux pass data
and a second for moving window averaged data.

8.2 Data Format(s)

The data files contain 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. Sample
data records are shown in the companion data definition file
(faamwdat.def).

9\. Data Manipulations

9.1 Formulae

Constants used in flux calculations:

The specific heat of air (Cp) is calculated as a function of the average
water vapor mixing ratio, ignoring the pressure-dependent isobaric
residual (Smithsonian Meteorological Tables, p. 339). In equation form,
Cp=Cp0 + b\*rbar, where Cp0=1004.42 J/kgK, b=1845.98, and rbar is the
average water vapor mixing ratio, in units of g/g of kg/kg.

The latent heat of vaporization, Lv, is calculated as a function of the
average temperature, Tbar, as Lv=Lv0 + c\*Tbar, where Lv0=3.15209e06
J/kg, and c=-2382.9 for Tbar in degrees Kelvin. These values were
obtained by a least-squares fit to values tabulate in the Smithsonian
Meteorological Tables, p. 343).

Formulas used for the various eddy covariance fluxes. In these
expressions, the angle brackets \<\> denote an average over the length
of the time series.

Sensible heat flux:

Sensible heat flux, H, calculated as H=(density of moist air)\*(Specific
heat of air at constant pressure)\*\<w\'\*theta\'\>. Here w is the
vertical air motion component (updraft), and theta is the air potential
temperature. Resulting units: W m\^-2.

Latent heat flux:

Latent heat flux, E, calculated as E=(density of moist
air)\*Lv\*\<w\'r\'\>,

where r is the water vapor mixing ratio. Resulting units: W m\^-2.

Carbon dioxide flux:

Carbon dioxide flux, A, calculated as A=(density of dry
air)\*\<w\'C\'\>, where C is the CO~2~ concentration expressed as mixing
ratio (mass CO~2~ per mass dry air). The units from this calculation
would be mass CO~2~/m\^2 s. By BORIS convention, however, the archived
units are converted to micromole CO~2~ m\^-2 s\^-1.

Momentum fluxes:

The various vertical fluxes of horizontal momentum are calculated as
(density of moist air)\*\<w\'vel\'\>, giving units of kg/ms\^2, where
vel is u, v, unat, or vnat. Here, (u,v) is the horizontal wind vector in
east-west and north-south coordinates, while (unat,vnat) is the vector
of along- and cross-wind components of the horizontal wind, with unat
parallel to the pass-average wind direction.

9.1.1 Derivation Techniques and Algorithms

Not applicable.

9.2 Data Processing Sequence

9.2.1 Processing Steps

As listed in Section 7.3, there are two basic categories of numbers
(statistics and fluxes) in the archived values for each pass. The first
category (groups 3, 4, and 6-10) are statistics and fluxes based on the
\"raw\" data, i.e., on the time series data as they were recorded and
processed. The second category (groups 12-16) are \"detrended.\" In
these cases the linear trends were removed by calculating an
equal-weight least-squares line fit (y=mx+b) for each variable, then
subtracting that line from the original series. Group 5 contains the
linear trends (the slopes, or m values) from those least-squares fits.
The fluxes for the first category (\"raw\") are based on the covariance
values w\'s\', where w\'=w-wmean, s=s\'-smean, wmean is the simple
arithmetic average of w, and smean is the simple arithmetic average of
the scalar s. The second category \"detrended\" fluxes are based on
w\'s\' where w\'=w-(fitted line for w) and s\'=s-(fitted line for s).

The moving window data values represent averages over 180-second
measurement periods with each period overlapping the period before and
the period after by 90 seconds. With the average King Air airspeed being
85-90 m/s, the segments will have an average length of 15.3 to 16.2 km.

9.2.2 Processing Changes

None.

9.3 Calculations

See 9.1.

9.3.1 Special Corrections/Adjustments

Time lag between CO~2~/H~2~O measurements and gust probe: Due to the
geometry of the instrument locations (See section 4.1.6), there is a
significant lag between measurements by the LICOR device (water vapor
and carbon dioxide) and the 3-D winds. Based on instrument placement,
external airflow velocities, and internal (sampling tubes) flow
velocities, the lag was predicted to be 0.3 sec. In contrast, the
distance between the gust probe tip and the Friehe temperature probe
causes negligible lag between the temperature and wind measurements.
Thus, the lag between the temperature and LICOR measurements should be
equivalent to that between the wind and LICOR measurements. The
predicted temperature-LICOR lag (0.3 sec) was verified by flying the
plane several times through the plume from a local power plant, at
distances close enough to the source that changes in temperature, water
vapor, and CO~2~ were very abrupt at the plume edges. Thus, prior to any
other calculations, the LICOR data are shifted 0.3 sec, to bring those
data in sync with the remainder of the data.

9.3.2 Calculated Variables

See lists of variables in sections 1.4, 7.1, and 7.3.

9.4 Graphs and Plots

Not applicable.

10\. Errors

10.1 Sources of Error

As with any time-series measurements, there are uncertainties in the
values of the resulting measured and derived quantities simply due to
the limits of the sampling techniques. Each archived flux and statistic
is a single sample, or single realization, of the measurement, and thus
has a higher level of uncertainty than if multiple measurements were
possible.

Sampling limits:

As detailed by Lenschow and Stankov (1986, J. Atmos. Sci., 43,
1198-1209), substantial uncertainties are present in single-pass
measurements of fluxes. Even to reduce such uncertainties below the 10%
range, for example, would require a single aircraft pass to be very long
(distance), in fact, so long that other uncertainties would result
from 1) having the BL characteristics change with time and 2) having the
flight track pass over changing surface characteristics. The most direct
technique available with aircraft to address this problem is to make
repeated, shorter passes along the same track or at least along similar
tracks. The fluxes and statistics from the individual passes may then be
combined to at least reduce the standard error of each measurement. This
strategy was incorporated into many of the King Air flight patterns.

Instrument limits:

See 11.2

10.2 Quality Assessment

An extensive intercomparison of the BOREAS flux aircraft has been
written and submitted for publication in an issue of J. Geophys. Rsch.
dedicated to BOREAS analyses (authorship: R. Dobosy, J. I. MacPherson,
R. Desjardins, R. D. Kelly, S. Oncley, and D. H. Lenschow). In that
text, King Air measurements, including means and variances of all the
flux variables, as well as the fluxes themselves, are compared with
corresponding values from the Canadian NRC Twin Otter and the NCAR
Electra, for multiple wing-to-wing passes at various times during the
1994 experiment. As of this writing, these comparisons are the best
available assessments of the overall data quality for the King Air, at
least in comparison with similarly instrumented platforms.

10.2.1 Data Validation by Source

None given.

10.2.2 Confidence Level/Accuracy Judgement

None given.

10.2.3 Measurement Error for Parameters

None given.

10.2.4 Additional Quality Assessments

None given.

10.2.5 Data Verification by Data Center

Data were examined for general consistency and clarity.

11\. Notes

11.1 Limitations of the Data

For each pass or segment of a pass, the statistics and fluxes are
archived for time series with simple arithmetic means removed and then
again for time series with simple linear trends removed. The first set
(\"demeaned\") thus represents the original, raw data with no filtering
applied. The second set (detrended) also represents unfiltered data,
having only the linear trends removed. In order to apply more
complicated, non-linear detrending or filtering methods, the original
data must be obtained.

11.2 Known Problems with the Data

Vertical velocity measurements:

Spectral density plots of vertical velocity (w) generally show a fairly
well defined inertial subrange, with -5/3 slope out to about 9 Hz, at
which point the effects of the anti-aliasing low-pass filter are
evident. Many of the w spectral plots do, however, show a slight
\"bulge\" above the -5/3 line in the range 0.1-1 Hz. As of this writing
(July 9, 1996) we believe this is an artifact of the post-flight
calculations. Examples of these spectra can be seen in the JGR
manuscript comparing the four BOREAS flux aircraft (Dobosy et al., 1996,
JGR dedicated issue).

High-rate H~2~O measurements (LICOR 6262):

The LICOR 6262 response is described by the manufacturer as being a 90%
response to step-function changes in concentration in 0.1 s. The
combination of this characteristic, any along-flow mixing in the sample
tubes, and the anti-aliasing filter are evident in the spectral density
plots for H~2~O mixing ratio. These plots generally show an inertial
subrange (slope -5/3) out to about 2 Hz, at which point the response
drops sharply. At 2 Hz, the SNR is usually about 20 dB. Implications of
this response for the flux calculations are that the H~2~O fluxes are
being resolved only to about 2 Hz (about 40 m for typical research
airspeeds).

CO~2~ measurements (LICOR 6262):

The response characteristics for CO~2~ are generally the same as for
H~2~O, except that the SNR at 2 Hz is usually 10 dB or less. As with
CO~2~, these figures imply that the CO~2~ fluxes are being resolved only
to about 2 Hz (about 40 m for typical research airspeeds).

11.3 Usage Guidance

Note that although there are less than 100 records in any data file,
there are over 170 columns of data. Most spreadsheet software should be
able to handle up to 256 columns of data.

11.4 Other Relevant Information

None given.

12\. Application of the Data Set

These data can be used to obtain study area and regional scale estimates
of the various fluxes.

13\. Future Modifications and Plans

None given.

14\. Software

14.1 Software Description

Not applicable.

14.2 Software Access

Not applicable.

15\. Data Access

15.1 Contact for Data Center/Data Access Information

These BOREAS data are available from the Earth Observing System Data and
Information System (EOS-DIS) 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

15.2 Procedures for Obtaining Data

BOREAS data may be obtained through the ORNL DAAC World Wide Web site at
http://www-eosdis.ornl.gov/ or users may place requests for data by
telephone, electronic mail, or fax.

15.3 Output Products and Availability

Requested data can be provided electronically on the ORNL DAAC\'s
anonymous FTP site or on various media including, CD-ROMs, 8-MM tapes,
or diskettes.

The complete set of BOREAS data CD-ROMs, entitled \"Collected Data of
the Boreal Ecosystem-Atmosphere Study\", edited by Newcomer, J., et al.,
NASA, 1999, are also available.

16\. Output Products and Availability

16.1 Tape Products

Not applicable.

16.2 Film Products

Not applicable.

16.3 Other Products

Comma-delimited ASCII text files.

17\. References

17.1 Platform/Sensor/Instrument/Data Processing Documentation

See refs listed in section 17.2

17.2 Journal Articles and Study Reports

Baijards, S.A.M., S. O. Ogunjemiyo, R. D. Kelly, and P. H. Schuepp.
1996: Preliminary analysis of dual aircraft boundary layer grid flux.
Submitted to J. Geophys.

Rsch.

Baijards, S. A. M. and R. D. Kelly 1996. Conditional sampling applied to
BOREAS aircraft data., Preprints, 22nd Conf. on Agric. and Forest
Meteor., 28 Jan. - 2 Feb. 1996, Atlanta, GA.

Betts, A. K., R. L. Desjardins, and J. I. MacPherson 1989: Boundary
layer heat and moisture budgets. Spring 1989 meeting of Amer. Geophys.
Union, May 7-11, 1989, Baltimore.

Betts, A. K., R. L. Desjardins, and J. I. MacPherson. 1990. Boundary
layer heat and moisture budgets from FIFE. AMS Symposium on First ISLSCP
Field Experiment (FIFE), 70th AMS Annual Meeting, Feb. 5-9, 1990,
Anaheim, CA.

Dobosy, R.J., T. L. Crawford, J. I. MacPherson, R. L. Desjardins, R. D.
Kelly, S.P. Oncley, and D. H. Lenschow. 1994. Intercomparison among the
four flux aircraft at BOREAS. Submitted to J. Geophys. Rsch.

Kelly, R. D., J. I. MacPherson, R. J. Dobosy, and T. L. Crawford 1996.
BOREAS 1994 intercomparison among three flux aircraft., Preprints, 22nd
Conf. On Agric. and Forest Meteor., 28 Jan. - 2 Feb. 1996, Atlanta, GA.

McDermott, M.L. and R. D. Kelly. 1996. Variation of boundary layer
fluxes with heterogeneous surface vegetation and seasonal change.
Submitted to J. Geophys. Rsch.

McDermott, M. L. and R. D. Kelly 1995. Fluxes over a heterogeneous
forest., Preprints 11th Symposium on Bound. Layers and Turbulence,
Charlotte, NC, 27-31 March, 1995.

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

Sellers, P., F. Hall, H. Margolis, B. Kelly, D. Baldocchi, G. den
Hartog, J. Cihlar, M.G. Ryan, B. Goodison, P. Crill, K.J. Ranson, D.
Lettenmaier, and D.E. Wickland. 1995. The boreal ecosystem-atmosphere
study (BOREAS): an overview and early results from the 1994 field year.
Bulletin of the American Meteorological Society. 76(9):1549-1577.

Sellers, P., F. Hall, and K.F. Huemmrich. 1996. Boreal
Ecosystem-Atmosphere Study: 1994 Operations. NASA BOREAS Report (OPS DOC
94).

Sellers, P. and F. Hall. 1996. Boreal Ecosystem-Atmosphere Study:
Experiment Plan. Version 1996-2.0, NASA BOREAS Report (EXPLAN 96).

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

Sellers, P.J., F.G. Hall, R.D. Kelly, A. Black, D. Baldocchi, J. Berry,
M. Ryan, K.J. Ranson, P.M. Crill, D.P. Lettenmaier, H. Margolis, J.
Cihlar, J. Newcomer, D. Fitzjarrald, P.G. Jarvis, S.T. Gower, D.
Halliwell, D. Williams, B. Goodison, D.E. Wickland, and F.E. Guertin.
1997. BOREAS in 1997: Experiment Overview, Scientific Results and Future
Directions. Journal of Geophysical Research 102 (D24): 28,731-28,770.

17.3 Archive/DBMS Usage Documentation

None given.

18\. Glossary of Terms and abbreviations

Abbreviations used in weather notes:

cu cumulus

st status

ci cirrus

sct scattered

Zi inversion height above ground

H haze

K smoke

cist cirrostratus

clr clear

ovc overcast

RW- light rain showers

acu altocumulus

Abbreviations in flight descriptions:

rt round trip

agl above ground level (in feet)

msl above mean sea level (in feet)

mult multiple

TAS true airspeed

lvl level

wind \"L\" \"L\" with one leg parallel to wind

direction, flown as at least one round trip.

19\. List of Acronyms

BOREAS - BOReal Ecosystem-Atmosphere Study

BORIS - BOREAS Information System

DAAC - Distributed Active Archive Center

EOS - Earth Observing System

EOSDIS - EOS Data and Information System

GSFC - Goddard Space Flight Center

NASA - National Aeronautics and Space Administration

ORNL - Oak Ridge National Laboratory

URL - Uniform Resource Locator

NCAR - National Center for Atmospheric Research

NRC - National Research Council, Canada

BL - atmospheric Boundary Layer

20\. Document Information

20.1 Document Revision Date

Written: 16-JUL-1996

Last Updated: 11-Feb-1999

20.2 Document Review Date(s)

BORIS Review: 08-Feb-1999

Science Review:

20.3 Document ID

20.4 Citation

20.5 Document Curator

20.6 Document URL