4

4.0 MISSION DESIGN

The objectives of the TRACE-P study are discussed in Section 2.0. To accomplish these objectives, the mission design includes a pre-deployment phase involving ozonesonde launches from six sites in Hong Kong, Japan, and Taiwan, the field deployment phase utilizing the instrumented NASA DC-8 and P-3B aircraft from two operational sites in the western Pacific, and the post deployment analyses and reporting phase. The pre-deployment phase was initiated in March 2000, and continues through March 2002; the field deployment phase is scheduled for early spring 2001; and the analyses and reporting phase is scheduled for completion with submittal of manuscripts by the investigators for publication TBD.

4.1 Measurement Requirements

The instrument detection limits and time resolutions for species/parameter measurements are listed in Table 4.1-1. A description of the priority ratings and footnotes for Table 4.1-1 are listed in Table 4.1-2.

Table 4.1-1 Measurement Requirements for the DC-8 and P-3B Instrumentation

Species/Parameter	Detection Limit^(a)	Time Resolution	DC-8 Priority	P-3B Priority
O₃ (in situ)	3 ppbv 1 ppbv^(b)	1 sec	1	1
NO	3 pptv 1 pptv^(b)	1 min 10 sec^(b)	1	1
H₂O^(c)	3 ppmv	1 min 10 hz^(b)	1	1
CO	5 ppbv	1 sec	1	1
Atmospheric State Parameters ^(d)	Aircraft standard	1 sec	1	1
Vertical Winds^(d)	10 cm/sec	10 hz	NA	2
Remote ozone (nadir and zenith)	5 ppbv	Z<500 m X<60 km	1	NA
Remote aerosol (nadir and zenith)	Scattering ratio .02 @ 600 nm	Z<60 m X<500 m	2	3 (nadir)
Range-resolved remote water vapor	0.01g/kg	Z< 500m X<70km	2	NA
PAN	5 pptv	5 min	2	2
HNO₃	5 pptv	5 min	2	2
H₂O₂	10 pptv	5 min 1 min^(b)	2	2
CH₃OOH	10 pptv	5 min	2	2
Speciated Hydrocarbons (C₂-C₈)	20 pptv	5 min	2	2
Halocarbons	2 pptv	5 min	2	2
OH	1x 10⁵ molec/cm³	5 min	2	2
HO₂	1x10⁷ molec/cm³	5 min	2	2
NO₂	5 pptv	1 min	2	2
CO₂	0.5 ppmv ^(e)	1 min	2	2
N₂O	0.5 ppbv ^(e)	1 min	2	2
CH₄	20 ppbv ^(e)	1 min	2	2
Acetone	50 pptv	5 min	2	3
Spectrally resolved nadir & zenith actinic flux for J-value determination	0.1 µw/nm/cm^-2 280 nm - 420 nm @ 1nm resolution	30 sec	2	2
J {O(¹D)}	2 X 10 ^-4 /s	30 sec	2	2
J {NO₂} ^(d) (nadir & zenith)	1 X 10^-4/s	30 sec	2	2
SO₂	5 pptv	5 min 1 min^(b)	2	2
Lightning events ^(d)	Range 400 km	<3 min hold time	2	2
CH₂O	50 pptv	5 min 1 min^(b)	2	2
Aerosols size/ number distribution	10 nm - 20 µm	5 min per scan	2	2
Aerosol composition (ionic analysis)	5 pptv	10 min<> 5 min^(b)	2	2
Range-resolved remote temperature sounding	2 K	1 km	2	NA
Black Carbon	0.1 µg/m³	5 min	3	2
In situ aerosol light scattering coefficient	10^-7/m	10 sec	3	3
Organic nitrates (Alkyl nitrates)	6 pptv	5 min	3	3
Condensation Nuclei	10/cm³	10 sec	4	2
Ultra fine aerosols	Size range 3-15 nm	5 min	3	2
DMS	1 pptv	5 min	3	3
H₂SO₄ ^(g)	2 x 10⁵ molec/m³	5 min	3	2
Alcohols	20 pptv	5 min	3	3
Organic acids	10 pptv	5 min	3	3
²²²Rn	0.05 Bq/SCM	5 min	3	NA
²¹⁰Pb	0.1 Bq/SCM	10 min 5 min^(b)	3	NA
⁷Be	1.0 Bq/SCM	10 min 5 min^(b)	3	NA
NH₃	10 pptv	5 min	3	3
Column content of trace gases (e.g., CO)	Species –dependent	10 min 5 min^(b)	3	3
Isotopic content of water vapor	Isotope-dependent	10 min 5 min^(b)	3	3
MSA^(g)	2 x 10⁵molec/cm^-3	1 min	4	4
DMSO^(g)	2 x 10⁶molec/cm^-3	1 min	4	4
HNO4	5 pptv	5 min	5	5
RO₂	0.1 pptv	5 min	5	5
>C₁ - Aldehydes	20 pptv	5 min	5	5
C₃ - ketones	20 pptv	5 min	5	5
Ethene/Propene	2 pptv	1 min with real time output	5	5
Size Resolved Single Particle Chemical Composition	Species-dependent	<1 min	5	5
Range-resolved measurement of other chemical species	Species-dependent	5 min	5	5

Table 4.1-2 Description of Priority Ratings and Footnotes for Table 4.1-1

Rating	Description	Meaning
1	Mission Critical	The measurement is essential to the interpretation of data related to the objectives of mission.
2	Very Important	The measurement is important to several scientific issues being addressed by the mission.
3	Important	The measurement is important to some scientific aspects of the mission. Space requirements of instrument will be a prime consideration for inclusion in the payload.
4	Less Important	Measurements would be useful but information not considered critical to interpretation of mission results. A measurement at this level will be considered only if it utilizes an instrument used also to make another measurement at the priority 1 or 2 level.
5	New Technology/ Very Important Measurement	Measurements involving instruments that represent the application of new technologies/approaches to measuring species of very high scientific interest. Measurement involves technical risk, but consideration will be given to including at least one such measurement in the payload.
(a) Detection limit at S/N=2 (b) Preferred characteristics (c) Water vapor at 1mm resolution will be provided by the GTE Project Office (d) Provided by GTE Project Office (e) Precision of measurement

4.2 Aircraft Investigations

Tables 4.2-1 and 4.2-2 list the Principal Investigators and measurements aboard the DC-8 and P-3B aircraft respectively. A brief description of each investigation, including measurement technique and characteristics of the parameters measured may be found at the GTE homepage on the internet (http://www-gte.larc.nasa.gov/). Layout of the instruments aboard each aircraft is shown at the same internet site and in Figures 4.2-1 and 4.2-2, which follow. Aircraft characteristics are listed in Appendix C of this document.

Table 4.2-1 DC-8 Investigators/Parameters

PI	Organization	Parameter
Bruce E. Anderson	NASA Langley	Ultra fine aerosols, aerosol size/number distribution, black carbon, in-situ aerosol light scattering coefficient, condensation nuclei
Eric C. Apel and Daniel D. Riemer	NCAR University of Miami	Alcohols, > C₁-aldehydes
Elliot L. Atlas	NCAR	Organic nitrates, halocarbons
Melody A. Avery and Stephanie Vay	NASA Langley	O₃, CO₂
Donald R. Blake	University of California – Irvine	CO, CH₄, speciated HC (C₂-C₈), DMS, halocarbons, organic nitrates
Edward V. Browell	NASA Langley	Remote O₃(N & Z), remote aerosol profiles (N & Z)
William H. Brune	Pennsylvania State University	OH, HO₂
Alan Fried	NCAR	CH₂O
Brian G. Heikes	University of Rhode Island	CH₃OOH, H₂O₂, CH₂O
Project Office (John Barrick)	NASA Langley	See Table 4.3-1
Glen W. Sachse	NASA Langley	CO, CH₄, N₂O, H₂O
Scott T. Sandholm	Georgia Institute of Technology	NO, NO₂
Richard E. Shetter	NCAR	Spectrally-resolved N & Z actinic flux for J-value determination, J{O(¹D)}, J{NO₂} (N & Z)
Hanwant B. Singh	NASA Ames	PAN, acetone, alcohols, organic nitrates
Robert W. Talbot	University of New Hampshire	HNO₃, SO₂, aerosol composition, ²¹⁰Pb, ⁷Be

Table 4.2-2 P-3B Investigators/Parameters

PI	Organization	Parameter
Elliot L. Atlas	NCAR	Organic nitrates, halocarbons
Melody A. Avery and Stephanie A. Vay	NASA Langley	O₃, CO₂
Alan R. Bandy	Drexel University	SO₂, DMS
Donald R. Blake	University of California – Irvine	CO, CH₄, speciated HC (C₂-C₈), DMS, halocarbons, organic nitrates
Christopher A. Cantrell	NCAR	HO₂, RO₂
Antony D. Clarke	University of Hawaii	Aerosol size/number distribution, black carbon, in-situ aerosol light scattering coefficient, condensation nuclei
Fred L. Eisele	Georgia Institute of Technology	OH, H₂SO₄, MSA, HNO₃
Frank Flocke	NCAR	PAN, PPN, MPPN
Yutaka Kondo	Tokyo University	NO, NO₂
Project Office (John Barrick)	NASA Langley	See Table 4.3-1
Project Office (John Barrick)	NASA Langley	_TAMMS_{(Latitude, Longitude, Pressure altitude, Static pressure, Impact pressure, Static temperature, Pitch, Roll, True heading, U, V, W, Specific humidity (q1011), Specific Humidity (LymanAlpha), Virtual potential temperature)}
Glen W. Sachse	NASA Langley	CO, CH₄
Richard E. Shetter	NCAR	Spectrally-resolved N & Z actinic flux for J-value determination, J{O(¹D)}, J{NO₂} (N & Z)
Rodney J. Weber	Georgia Institute of Technology	Ultra fine aerosols, aerosol composition

Figure 4.2-1 DC-8 Instrument Layout

Figure 4.2-2 P-3B Instrument Layout

4.3 Project Measurements

Table 4.3-1 presents the parameters describing meteorological, navigational, and other aircraft parameters or "housekeeping measurements" to be measured aboard the two aircraft. These measurements will be obtained by the DC-8 Data Acquisition and Distribution System (DADS) and the P-3B Project Data System (PDS) and are to be provided to all investigators by the GTE Project Office.

Table 4.3-1 TRACE-P Project Measurements

Parameter	Aircraft	Origin
Day	Both	1
Time	Both	1
Latitude	Both	1
Longitude	Both	1
Pitch	Both	1
Roll	Both	1
Wind speed	Both	1
Wind direction	Both	1
True air speed	Both	1, 3
Ground speed	Both	1
True heading	Both	1
Drift angle	DC-8	1
Pressure altitude	Both	1
Radar altitude	Both	1
Indicated air speed	DC-8	1
Vertical speed	DC-8	1
Distance to go	DC-8	1
Time to go	DC-8	1
Alignment status	DC-8	1
Align/from/to	DC-8	1
Mach Number	Both	1, 3
Cross track distance	DC-8	1
Desired Track	DC-8	1
Track angle error	DC-8	1
Track angle	Both	1
D/F point temp.	Both	2
D/F point temp. (2 & 3-stage)	DC-8	1
Static air temp.	Both	1,3
Total air temp.	Both	1,2
Potential temp.	Both	3
Cabin altitude	Both	2
Static Pressure	Both	1, 2
Differential pressure	P-3B	2
Partial pressure H₂O wrt ice	Both	3
Partial pressure H₂O wrt water	Both	3
Rel. humid. wrt ice	Both	3
Rel. humid. wrt water	Both	3
Sat. vapor press. of H₂O wrt ice	Both	3
Sat. vapor press. of H₂O wrt water	Both	3
IR surface temp.	Both	2
Sun elev. grd. ref.	DC-8	3
Sun azim. grd. ref.	DC-8	3
Sun elev. A/C ref.	DC-8	3
Sun azim. A/C ref.	DC-8	3
Forward nadir cloud video	Both	2
Storm scope	Both	2
Weather radar	DC-8	1
Polar Sat. images	DC-8	1
J (NO₂) zenith & nadir	Both	2

                                  Origin notes:   1-- aircraft sensor
                                                        2-- Project sensor
                                                        3-- calculated
                                                       (DC-8 listed first and P-3B second)

4.4 Ozonesonde Network

The pre-deployment phase of TRACE-P, consisting of a 12 ozonesonde network, was initiated to provide a time history of tropospheric ozone in the TRACE-P study region and to augment the data obtained aboard the aircraft during deployment. Ozonesonde balloons are released from Trinidad Head, California; Hilo, Hawaii; Sapporo, Tsukuba, Naha, and Kagoshima Japan; Java, Indonesia; Fiji; American Samoa; Hong Kong; Taiwan; and Cheju Island, Korea. More details of the network are given in Section 5.3.

4.5 Ground Measurements

4.5.1 Trace Gases

Continuous measurements of key species by a ground-based instrument will be conducted as part of the TRACE-P mission. PI Makoto Koike (Tokyo University) will measure tropospheric column amounts of carbon monoxide (CO), ethane (C₂H₆), and hydrogen cyanide (HCN) using Fourier-transform infrared spectrometers (FTIR). These instruments have been placed at the Moshiri (44.4°N, 142.3°E) and Rikubetsu (43.5°N, 143.8°E) Observatories and Tsukuba(36.0°N, 140.1°E), Japan.

FTIR measurements of CO, C₂H₆, and HCN will be made before, during, and after the TRACE-P deployment. Comparing results obtained by the DC-8 and P-3B aircraft with the FTIR results obtained during the TRACE-P deployment will provide important information on the spatial and temporal changes in these species. FTIR results obtained over a longer time period will provide useful information on the seasonal changes of these key species.

4.5.2 Ozonesondes

As part of the TRACE-P mission, PI Samuel J. Oltmans (NOAA) will operate two ozonesondes located at Trinidad Head, California (41.1°N, 124.8°W) and Hilo, Hawaii (19.4°N, 155.1°W). During TRACE-P deployment the soundings at Hilo, Hawaii and Trinidad Head, California will increase to three per week in order to better capture the frequency of events that may reach the mid-Pacific or west coast of the United States. Eighteen soundings will be performed during a six-week period at each site. In addition, weekly ozonesonde data beginning in early 2000 through spring 2002 will be provided to the TRACE-P data archive.

The enhanced number of ozone vertical profiles to be carried out at the two downwind sites during TRACE-P deployment will provide an opportunity to investigate the extent to which Asian emissions may be affecting ozone in the troposphere over the Pacific and the west coast of North America. Analysis of the ozone profile data will include the use of back trajectory calculations to characterize the flow patterns that bring air parcels to these sites and climatological trajectory analyses.

4.6 Meteorological Support

Overall meteorological support will be provided by investigator teams from the Massachusetts Institute of Technology and Florida State University. The Principal Investigators from these teams also serve as the Co-mission Meteorologists (see Table 3.0) providing forecasting for flight planning during the deployment phase of TRACE-P. Members of these teams will conduct post-mission research and analyses focused on understanding the meteorological setting of TRACE-P, and the meteorological impact on long-range transport of the chemical constituents measured during the expedition. The Hong Kong Observatory, Yokota Air Force Base Meteorology Office, and GTE Project Office will also provide additional meteorological support.

4.7 Model Investigations

In addition to the analyses and modeling studies that will be conducted as part of the experimental investigations listed in Tables 4.2-1 and 4.2-2, more focused modeling investigations (Table 4.7-1) will also be conducted by those Science Team members whose role is listed as "Theoretical Investigation" in Table 3.0-1.

The modeling activities are planned as a part of the "real-time" field activities as well as post-mission analyses. These analyses will incorporate various chemical models focusing on specific science issues as well as meteorological models for real time air mass trajectories. Table 4.7-1 lists the modeling products for each investigation, along with a brief description of the models.

Table 4.7-1 Modeling and Meteorological Analyses

PI	Organization	Parameter
Gregory R. Carmichael	University of Iowa	3D CTM and emission inventory
James H. Crawford	NASA Langley	Box model and meteorology support
Douglas D. Davis	Georgia Institute of Technology	Box model
Johann Feichter	Max-Plank-Institut fur Meteorologie	3D CTM and meteorology support
Henry E. Fuelberg	Florida State University	Meteorology support
Daniel J. Jacob	Harvard University	Box model and 3D CTM
Reginald E. Newell	MIT	Meteorology support
Michael J. Prather	University of California – Irvine	3D CTM
Anne M. Thompson	NASA Goddard	Meteorology support

4.8 Satellite Data Products

The use of satellite data products will play an integral part in the TRACE-P mission. In addition to the use of satellite data by Science Team members listed in Table 4.7-1 for modeling and meteorological analysis, some Science Team members will focus their analyses on satellite data products for mission planning and post mission analysis. These Science Team members are listed in Table 4.8-1 and in Table 3.0-1 with the role of "Satellite Data Analysis." This data will be available on the individual instrument web pages.

Table 4.8-1 Satellite Data Products

Organization

Products

Anne M. Thompson

NASA Goddard

SeaWIFS (smoke, dust, ocean color, clouds, lightning)

TOMS (total absorbing aerosol (smoke and dust), tropospheric ozone)

Charles R. Trepte

NASA Langley

SAGE II (tropospheric ozone and aerosol)

4.9 Aircraft Measurement Methodology

The combined instrumentation payload aboard the DC-8 and P-3B (see Tables 4.2-1 and 4.2-2) was selected to meet the objectives and tasks (addressed in Section 2.4) of the TRACE-P investigations. Differences in aircraft characteristics and payloads aboard each aircraft suggest differences in the methodology to be employed by the respective P-3B and DC-8 investigator teams in designing flight plans. For TRACE-P both planes will be focused on the single set of objectives and tasks given in Section 2.4.

The DC-8 payload, for example, includes the DIAL system, which provides an important capability for characterization of the ozone and aerosol structure above and below the DC-8 flight altitude. A significant addition to the capabilities of the DC-8 payload, over that during PEM-Tropics A and B is the measurement of aerosols. The DC-8 aircraft has the capability for longer range and higher altitude coverage than the P-3B aircraft. Because of these important characteristics of the aircraft capability and payload, it is anticipated that the DC-8 flights will tend to emphasize characterization of ozone photochemical precursors concentrations on a very large scale, together with a more detailed air mass characterization based on measurements of both photochemical as well as non-photochemical species.

The P-3B's characteristics and payload differ from the DC-8's in several important ways. For example, it operates more efficiently at low altitudes. It will also have instrumentation for making hydroxyl radical measurements as well as systems for measuring several important sulfur compounds and aerosol composition. In addition, the P-3B will be instrumented for turbulent air motion measurements (e.g., TAMMS). The hydroxyl and sulfur instrumentation should make possible a more in-depth examination of both the photochemical oxidizing characteristics of the tropical troposphere, and sources and critical transformation processes controlling atmospheric sulfur. The TAMMS system, on the other hand, will offer the capability for boundary layer flux measurements of selected species. Because of these payload and operational characteristics, it is anticipated that the P-3B flights will tend to emphasize process-oriented studies associated with sulfur and ozone/hydroxyl photochemistry and include some boundary layer flux investigations.

The locations of the experiments aboard each aircraft are given in Figures 4.2-1 and 4.2-2 and the GTE homepage (http://www-gte.larc.nasa.gov/). Aircraft characteristics are listed in Appendix C.

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