Global Tropospheric Experiment Transport and Atmospheric Chemistry near the Equator-Atlantic (TRACE A) Langley ASDC Data Set Document

This document provides information on data products obtained during the GTE TRACE A atmospheric science expedition conducted over Eastern Brazil, the South Atlantic Ocean and South Africa during September* and October 1992. The objective of the mission were (1) to study the relative contributions of the photochemistry and the large- and small-scale circulation features to the enhanced ozone concentrations observed over the tropical Atlantic Ocean and (2) to characterize and quantify the source and transport of primary and secondary ozone precursors associated with biomass burning in South America and southern Africa. Measurements were made primarily by investigators' instruments located on the NASA DFRC DC-8 airborne laboratory. Also provided are a list of principal investigators, a brief summary of measurement techniques and a list of publications.

*Second and remaining flights delayed by one month due to repairs required to a damaged landing gear on the DC-8. Second test flight was accomplished on 9/18/92.

This document provides information for the following four data sets:

trdc8mXX.zip:	Measurements acquired aboard the DC-8 aircraft during flight XX
trsat.zip:	Daily corrected version 6 TOMS data for the TRACE-A study region
trbnd.zip:	CO, O3, N2O, CH4, and CO2 measurements aboard the INPE-Brazilian Bandeirante aircraft
trsndasc.zip:	Ozonesonde data from Ascension Island
trsndcon.zip:	Ozonesonde data from Brazzaville, Congo
trsndcui.zip:	Ozonesonde data from Cuiaba, Brazil
trsndeto.zip:	Ozonesonde data from Etosha Pan, Namibia
trsndnat.zip:	Ozonesonde data from Natal, Brazil
trsndpor.zip:	Ozonesonde data from Porto Nacional, Brazil
trsndpre.zip:	Ozonesonde data from Pretoria, South Africa

The investigators involved in the TRACE A mission were funded by NASA. The funded investigators, their organization and their grant, agreement or contract were:

Investigator	Organization	Grant
Aircraft:
J. Bradshaw	Georgia Tech	NAG-1-1415
E. Browell	NASA Langley	N/A
G. Gregory	NASA Langley	N/A
B. Heikes	U of Rhode Island	NAG-1-1395
S. Rowland	U of California-Irvine	NAG-1-783
G. Sachse	NASA Langley	N/A
H. Singh	NASA Ames	N/A
R. Talbot	U of New Hampshire	NAG-1-1233
Modeling:
J. Fishman	NASA Langley	N/A
D. Jacob	Harvard	NAG-1-1421
T. Krishnamurti	Florida State U	NAG-1- 1312
A. Thompson	NASA Goddard	N/A

Aircraft data sets are available for each investigation for each flight. Airborne measurements were typically obtained at constant altitude over the Atlantic Ocean during transit flights (i.e. "survey" flights), and over multiple altitudes closer to Brazil and southern Africa during flight from the intensive sites. Flight missions were conducted during TRACE A from August 18 through October 26, 1992. Section 4.b lists the flight dates. Flight tracks and profiles are shown in Fishman et al., [1996]. The duration, altitude range, ascent and descent rate, and flight path for each mission varied depending on mission objectives and environmental conditions. Further information about the measurement region and time frame may be found in the Journal of Geophysical Research, Vol. 101, No. D19, 23865-23879, October 30, 1996.

This data collection includes all of the in-situ aircraft (DC-8 & INPE Bandeirante), ozonesonde and TOMS satellite data submitted to the GTE data archive by the TRACE A investigators listed in Section 1.d. Included are the atmospheric chemistry, meteorological and navigational data recorded aboard the NASA Ames DC-8 airborne laboratory, the INPE Bandeirante aircraft, ozonesonde and TOMS satellite data. Not included in this archive are fire count satellite data, NOAA satellite imagery, rawinsondes, kinematic trajectories, modeling data and merged data sets. These data can be found at the GTE data archive at http://www-gte.larc.nasa.gov/.

TRACE A and SAFARI investigators have both individually reported the results of their investigations in the Journal of Geophysical Research, Vol. 101, No. D19, October 30, 1996.

There are data sets available from the Langley ASDC for 13 other GTE missions conducted from 1983 to 2001. See the GTE home page at http://www-gte.larc.nasa.gov and/or http://eosweb.larc.nasa.gov/PRODOCS/gte/table_gte.html for a description of the available data.

John D. Barrick
MS 483
NASA Langley Research Center
Hampton VA 23681-0001
Telephone: 757-864-5831
Fax: 757-864-5841
E-mail: j.d.barrick@larc.nasa.gov

John Bradshaw (Principal Investigator, Deceased)
Scott Sandholm (Co-Investigator)
Georgia Institute of Technology
Earth and Atmospheric Sciences
Baker Building, Room 107
923 Dalney Street
Atlanta GA 30332-0340
Telephone: 404-894-3895/3824
Fax: 404-894-5073
E-mail: ss27@prism.gatech.edu

Edward V. Browell
Mail Stop 401A
NASA Langley Research Center
Hampton VA 23681-0001
Telephone: 757-864-1273
Fax: 757-864-7790
E-mail: e.v.browell@larc.nasa.gov

Gerald L. Gregory (retired)
NASA Langley Research Center

Brian G. Heikes
University of Rhode Island
Graduate School of Oceanography
South Ferry Road
Narragansett RI 02882-1197
Telephone: 401-874-6810/6683
Fax: 401-874-6898
E-mail: zagar@notos.gso.uri.edu

Dean Lauritsen
Atmospheric Technology Division
Surface and Sounding Systems Facility
NCAR
P O Box 3000
Boulder CO 80307-3000
Telephone: 303-497-1000
Fax: 303-497-8770

F. Sherwood Roland
University of California-Irvine
Department of Chemistry
Irvine, CA 92717
Telephone: 714-856-6016
Fax: 714-725-2905
E-mail: rowland@uci.edu

Glen W. Sachse
MS 472
NASA Langley Research Center
Hampton VA 23681-0001
Telephone: 757-864-1566
Fax: 757-864-8818
E-mail: g.w.sachse@larc.nasa.gov

Hanwant Singh
NASA Ames Research Center
Singh Group
Mail Stop 245-5
Moffett Field CA 94035
Telephone: 415-604-6769
Fax: 415-604-3265
E-mail: hb_singh@arc.nasa.gov

Robert W. Talbot
University of New Hampshire
Institute of Earth, Oceans, Space
Morse Hall
Complex Systems Research Center
Durham NH 03820
Telephone: 603-862-1546
Fax: 603-862-0188
E-mail: rwt@christa.unh.edu

Don Blake
University of California-Irvine
Department of Chemistry
Irvine, CA 92717
Telephone: 714-856-4195
Fax: 714-725-2905
E-mail: dblake@orion.oac.uci.edu

Jack Fishman
NASA Langley Research Center
Mail Stop 401A
Hampton VA 23665-5225
Telephone: 804-864-2720
Fax: 804-864-7790
E-mail: j.fishman@larc.nasa.gov

Volker Kirchhoff
Instituto Nacional de Pesquisas Espaciais
C. P. 515
12201 Sao Jose dos Campos
Sao Paulo, Brazil
Telephone: (55) 123-41-8977
Fax: (55) 123-21-8743

Robert J. McNeal (retired)
NASA Headquarters

James M. Hoell, Jr. (retired)
NASA Langley Research Center

T. Krishnamurti
Florida State University
Department of Meteorology
Tallahassee FL 32306-3034
Telephone: 904-644-2210
Fax: 904-644-8579
E-mail: tnk@in.met.fsu.edu

Henry Fuelberg
Florida State University
Department of Meteorology
Tallahassee FL 32306-3034
Telephone: 904-644-6466
Fax: 904-644-9642
E-mail: fuelberg@met.fsu.edu

Mark Shipham (no longer at NASA LaRC)

Richard J. Bendura (retired)
NASA Langley Research Center

Leo DeGreef (no longer at NASA Ames)
Airborne Science Program Office
MS D1623H
Edwards, CA 93523-0273
Phone: (661) 276-7453
Fax: (661) 276-3719
E-mail: airsci.program.coordinator@dfrc.nasa.gov

Jacqueline Johnson (no longer at ST Systems)
ST Systems Corp.

Leo DeGreef (no longer at NASA Ames)
Joseph W. Drewry (retired)
NASA Langley Research Center

Joseph W. Drewry (retired)
NASA Langley Research Center

Meinrat O. Andreae - SAFARI
Max Planck Institute for Chemistry
Postfach 3060
D-6500 Mainz
Federal Republic of Germany
Telephone: (11)49-6131-305-420
Fax: (011)49-6131-305-487

Dominique Nganga
Marien Ngouabi University
B. P. 69 Brazzaville
Republic of Congo
Telephone: N/A
Fax: (011) 242-83-6642

Jannette Lindesay - SAFARI
Climatology Research Group
University of Witswatersrand
P O Wits, Johannesburg 2030,
South Africa
Telephone: (011)27-11-716-2998
Fax: (011)27-11-716-3000

Potential usage and applications of the described data sets can be seen in the articles that comprise the Journal of Geophysical Research TRACE A Special Section (Vol.101, No. D19 October 30, 1996) and the Second Scientific Conference of the International Global Atmospheric Chemistry (IGAC) Project, September 1994.

For convenience of the users, the calculated variables below are provided.

Mach Number, M:
	M = Mach Number Ps = Static Pressure Qc = Differential Pressure

Static Air Temperature, Ts:
	TS = Static Air Temperature (°K) TT = Total Air Temperature (°K) γ = 1.4, ratio of specific heat of air at constant pressure and volume

True Air Speed, TAS:
	TAS = True Air Speed (knots) TS = Static Air Temperature (°K) M = Mach Number a = Speed of Sound

Potential Temperature, θ:
	θ = Potential Temperature (°K) TS = Static Air Temperature (°K) Ps = Static Pressure (mb)

Vapor Pressure, e :

e_water (mb) = [1.0007 + (3.46 * 10^-6 * P_S)] * 6.1121* EXP[17.502 * T/(240.97 + T)]

e_ice (mb) = [1.0003 + (4.18 * 10^-6 * P_S)] * 6.1115* EXP[22.452 * T/(272.55 + T)]

e = Partial Pressure of Water Vapor (mb)
P_S = Static Pressure (mb)
T = Static Air Temperature (°C) for Saturation Vapor Pressure
or
T = Dew/Frost Point(°C) for Partial Pressure of Water Vapor

Note:

1. ProjDP of zero or greater should be used to derive the partial pressure of water vapor w.r.t water (e_water) and the ProjDP less than zero should be used to derive the partial pressure of water vapor w.r.t ice (e_ice).

2. StatTempDegC and ProjDP parameters recorded in the P-3B data set are substituted to calculate saturation vapor pressure and partial pressure of water vapor , respectively.

3. TSDEGC and ProjDP parameters recorded in the DC-8 data set are substituted to calculate saturation vapor pressure and partial pressure of water vapor, respectively. Also notice in the DC-8 data set there is a redundant static air temperature measurement, TSCALC, which is calculated by DADS. Although TSDEGC and TSCALC track closely they can diverge by ≈1° at the low and high ends of the measurement range.

Specific Humidity, q:
Mixing Ratio, r:
Note: ppmv = 1.608 * ppmw ppmw = 0.622 * ppmv

Relative Humidity, %:
w.r.t. water,	w.r.t. ice,

This data set contains all of the in-situ aircraft (DC-8 and Bandeirante), ozonesonde and TOMS satellite data submitted to the GTE data archive by the TRACE A investigators listed in Section 1.d. Included are the atmospheric chemistry, meteorological and navigational data recorded aboard the NASA Ames DC-8 airborne laboratory, the INPE Bandeirante aircraft, ozonesonde and TOMS satellite data. Not included in this archive are fire count satellite data, NOAA satellite imagery, rawinsondes, kinematic trajectories, modeling data and merged data sets. These data can be found at the GTE data archive at http://www-gte.larc.nasa.gov/. No additional data products relevant to TRACE A are anticipated.

This data is available online or on a CD-ROM via the LaRC ASDC at http://eosweb.larc.nasa.gov and from the GTE data archive at http://www-gte.larc.nasa.gov. Users may also order data by letter, telephone, and electronic mail from the ASDC (see 3e).

Science, Users and Data Services Group
Atmospheric Science Data Center
MS 157D
Langley Research Center
Hampton, VA 23681 USA
Phone: 757-864-8656
Fax: 757-864-8807
E-mail: larc@eos.nasa.gov
Internet: http://eosweb.larc.nasa.gov

Airborne measurements were made over Brazil, the South Atlantic Ocean and southern Africa. A more detailed description of the surface level environmental characteristics for the experiment region is provided in the individual papers for each investigation included in the Journal of Geophysical Research, Vol. 101, No. D19 October 30, 1996. Additional information may be found in other publications authored by the principal investigators or on the GTE homepage at http://www-gte.larc.nasa.gov.

TRACE A flight missions were conducted during September and October, 1992. The duration, altitude range, ascent and descent rate, and flight path of each mission varied depending on mission objective and environmental conditions. The nominal airspeed ranged from greater than 500 knots (approximately 575 mph) at 11 km altitude to 150 knots (approximately 175 mph) at 3.7 km.

Data Platforms	Min Lat	Max Lat	Min Lon	Max Lon
DC-8 Aircraft	38S	44N	126W	40E
Bandeirante Aircraft	17S	10S	56E	48W
TOMS	40S	10N	50E	80W

Ozonesonde Launch Site	Latitude	Longitude
Ascension Island	8.00S	15.00W
Congo	4.28S	15.25E
Cuiba	15.30S	56.00W
Etosha	19.20S	15.90E
Natal	6.00S	35.00W
Porto	10.80S	48.40W
Pretoria	25.90S	28.20E

TRACE A aircraft missions were conducted from 8/18/92* through 10/31/92. The dates and times for each mission are given in Fishman et al., [1996]. Ground site measurements were obtained from (date) to (date).

Data Platform	Begin Date	End Date
DC-8 Aircraft	8/18/92*	10/26/92
Bandeirante Aircraft	9/9/92	10/1/92
TOMS	09/01/92	10/31/92

Ozonesonde Launch Site	Begin Date	End Date
Ascension Island	7/28/90	10/24/92
Congo	4/6/90	10/20/92
Cuiba	9/18/92	10/10/92
Etosha	9/9/92	10/18/92
Natal	3/12/90	10/23/92
Porto	9/15/92	10/1/92
Pretoria	9/2/92	10/7/92

*Second and remaining flights delayed by one month due to repairs required to a damaged landing gear on the DC-8. Second test flight was accomplished on 9/18/92.

Not all of the parameters are in each data set granule. Also, the ranges vary between data sets and between granules within each data set. Species measured are given in Fishman et al., [1996].

Parameter Description

The variables measured are standard atmospheric chemical and meteorological species requiring no further elaboration here.

Unit of Measurement

The units of measure vary widely depending on species and measurement environment and are addressed in the individual papers for each investigation included in the Journal of Geophysical Research, Vol. 101, No. D19, October 30, 1996.

Parameter Range

The ranges of data vary widely depending on species and measurement environment and are addressed in the individual papers for each investigation included in the Journal of Geophysical Research, Vol. 101, No. D19, October 30, 1996.

Sample Data Record

The GTE Data Format Document at http://eosweb.larc.nasa.gov/guide/gte/gte_fmt.html contains examples of each data set type.

The sources of error vary depending on species and measurement environment and are addressed in the papers included in the TRACE A special issue of the Journal of Geophysical Research, Vol. 101, No. D19, October 30, 1996, and/or papers referenced in that publication and readme files and/or header records associated with each data file.

1. Known Problems with the Data:

   None reported for the current archive version. See the readme files and header records included with each data set for information provided by the responsible investigator.

2. Future Modifications and Plans:

   The data sets submitted to the ASDC are considered final and no further updates are planned.

Details of data acquisition and materials are addressed in the papers contained in the Journal of Geophysical Research TRACE A Special Section (Vol.101, No. D19, October 30, 1996) and the Second Scientific Conference of the International Global Atmospheric Chemistry (IGAC) Project, September 1994

Journal of Geophysical Research, Vol. 101, No. D19, October 30, 1996.

Second Scientific Conference of the International Global Atmospheric Chemistry (IGAC) Project, Fuji-Yoshida, Japan, September 5-9, 1994.

GTE Bibliography (http://www-gte.larc.nasa.gov/gte_pubs_update.htm)

Fishman, J., J. M. Hoell, R. D. Bendura, R. J. McNeal, V. W. J. H. Kirchhoff, NASA GTE TRACE A Experiment (September-October 1992): Overview, J. Geophys. Res., Vol. 101, 23865-23879, October 30, 1996.

ASDC - Atmospheric Science Data Center
Bnd - Brazilian airplane (Bandeirante)
DFRC - Dryden Flight Research Center
EOSDIS - Earth Observing System Data and Information System
FSU - Florida State University
GTE - Global Tropospheric Experiment
IMS - Information Management System
INPE - Instituto Nacional de Pesquisas Espaciais
LaRC - Langley Research Center
NASA - National Aeronautics and Space Administration
NCAR - National Center for Atmospheric Research
NOAA - National Oceanographic and Atmospheric Administration
ProjDP - Project Dew Point
SAFARI - Southern African Fire-Atmosphere Research Initiative
TOMS - Total Ozone Mapping Spectrometer
TRACE A - Transport and Chemistry near the Equator in the Atlantic
TSCALC - Static temperature, calculated by DADS
TSDEGC - Static temperature, measured directly, in Celsius

Creation Date:

October 1996

Revision Date:

October 31, 1996; May 29, 1997; November 24, 1997; November 2003

Review Date:

October 31, 1996; May 29, 1997; November 24, 1997; November 2003

Identification:

Curator:

Langley DAAC User and Data Services Office
Telephone: (757) 864-8656
FAX: (757) 864-8807
E-mail: larc@eos.nasa.gov

URL:

http://eosweb.larc.nasa.gov/GUIDE/dataset_documents/gte_tracea_dataset.html