TRACE-P P-3B Status Updates

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Flight 16: Yokota Local 2 (24 March, 2001)

This flight was planned to begin with an intercomparison leg at 17 Kft with the DC-8.  Following the intercomparison, low altitude sampling legs were planned along the southern coast of Japan and to the north in the Sea of Japan.  Model predictions indicated both regions should have surface outflow below about 6 Kft with cleaner conditions above.


The intercomparison leg at the beginning of the flight went well.  Conditions were fairly constant for most species, although ozone showed some variability ranging from 70 to 90 ppbv.  Other measurements showed increased structure during a period of turbulence about 13 minutes into the 20 minute intercomparison. Sampling along the southern coast of Japan did show surface outflow below 6 Kft as expected.  CO was highly variable with mixing ratios often in the 300 ppbv range and sometimes exceeding 400 ppbv.  NOy and SO2 were consistently at ppbv levels.  Crossing Japan to the north, very different conditions were encountered over the Sea of Japan.  At all altitudes, CO rarely exceeded 200 ppbv and was often around 100 ppbv.  Although background levels for all species were lower, several plumes were encountered from the boundary layer up to altitudes of 10Kft with ppbv level enhancements in SO2 and NOy (which had a large fraction attributed to PAN).  These plumes also contained large enhancements in CN and smaller enhancements in ozone, CO, and DP.  The Georgia Tech group reported that aerosol composition was similar to the north and south of Japan indicating a mixture of dust and anthropognic aerosol.  Despite the similarity in composition, aerosol mass loading was 5 times higher south of Japan as compared to the north.

Flight 15: Yokota Local 1

This flight to the east of Japan was intended to profile across a frontal boundary near 150E, sample beyond the front, and cross the frontal zone again on the return to Yokota.

Results:  Heading out to the frontal zone, vertical profiles revealed ozone to be about 10 ppbv lower beyond the front.  CO values were similar below 8 Kft and were lower beyond the front at higher altitudes.  CO values were rather low both behind and beyond the front falling mostly in the 100-200 ppbv range.  The vertical ascent at 40N fell within the frontal zone and showed almost no gradient in the CO (120 ppbv) and ozone (60 ppbv)profiles while relative humidity was near 100% between the surface and 15 Kft.  Returning across the frontal zone, CO values remained less than 200 ppbv until reaching the boundary layer.  At 5.5 Kft, evidence of new particle formation was reported by the UH group, and both ultrafine and fine particle counts showed a strong correlation with variations in NOy.  On the final boundary layer run, polluted air with CO up to 400 ppbv and NOy up to 3 ppbv were observed.  PAN was measured to be the dominant NOy species through most of the flight often accounting for 40-50% of total NOy.  On the approach into Yokota, strong pollution encountered at 4 Kft included CO in excess of 700 ppbv, CO2 in excess of 400 ppmv, NOy greater than 20 ppbv, and PAN over 3 ppbv.

Flight 14: Okinawa-Yokota Transit  

This flight between Okinawa and Yokota was planned to include a northbound leg along 124.5E beginning at 30N stretching into the Yellow Sea up to 37N, then south again before heading east toward Yokota AFB, Japan.  This mission was intended to sample the same area of the Yellow Sea as flight 13 to capture strong surface level outflow not present on the previous flight.  

Results:  On the initial ascent from Okinawa, a layer of elevated CO and NOy was observed between 5-10 Kft.  Clean chemical conditions prevailed over the early portion of the flight into the Yellow Sea down to 5 Kft, although a large dust plume was encountered at 10Kft.  The first polluted conditions were encountered on a descent from 5000 to 500 ft with the most polluted conditions persisting in the lowest 1000 ft.  CO was sustained above 700 ppbv and exceeded 1 ppm.  SO2, NOy, and PAN were also sustained above ppbv levels.  Dust was also encountered several more times during the flight between 5 and 10 Kft.  Flying eastward toward Yokota, volcanic emissions were encountered at 4.5 Kft with variations in SO2 of several ppbv accompanied only by enhancements in CN and H2SO4.  On the final leg into Yokota, O3 reaching 122 ppbv was encountered at 18 Kft. 

Flight 13: Hong Kong-Okinawa Transit  

This flight between Hong Kong and Okinawa was planned to include a northbound leg along 124.5E beginning at 22N to the east of Taiwan stretching into the Yellow Sea up to 37N, then south again into Okinawa.  Model products predicted strong low level outflow north of 25N and centered between 4-12Kft.  

Results:  On the initial ascent from Hong Kong, an interesting layered structure was observed in CO, O3, NOy, and CN.  10 distinct layers were observed between the inversion (4.5Kft) and 19Kft.  Moving eastward to the south of Taiwan, the atmosphere was fairly clean at all altitudes as expected.  The first polluted conditions were encountered on a descent to the surface with CO exceeding 200 ppbv below 4000 ft.  At 500 ft, NOy exceeded 3 ppbv and NO was sustained in the 300-500 pptv range.  During this time northerly winds were encountered although southerly winds were forecast.  Over the Yellow Sea, CO maximized between 3000-7000 ft with sustained values above 400 ppbv and periods above 600 ppbv.  Below 3000 ft, CO was less, around 200 ppbv.  Conversely, NOy and SO2 were maximized near the surface at ppbv levels.

Flight 12: Hong Kong Local 4  

The P-3B took a track heading north to the east of Taiwan along 124.5E. This track was selected to attempt to sample a stratospheric intrusion expected just north of 26N.  Returning to Hong Kong a short leg of high altitude sampling into the South China Sea was planned to look for potential biomass burning outflow.  

Results:  A layer of elevated CO and NOy was observed on the initial ascent between 7 and 10Kft.  This layer was not present on the initial descent about 1 hour later.  As in previous flights to the east and north, boundary layer legs were characterized by high variability in NO, NOy, SO2, and CN suggestive of shipping lanes.  Numerous ship sightings were also reported from the cockpit.  An uncooperative air traffic control representative prevented sampling of the expected stratospheric intrusion by forcing the P-3B to stay below 7.5Kft north of 26N.  On reaching the South China Sea, conditions were fairly clean up to 20Kft with CO decreasing with altitude. Between 20-24Kft, a few thin layers were observed with elevated CO, NO, NOy, O3, and CN.  Although not dramatic, CO at 24Kft was higher than that at 20Kft.  Another layer at 22Kft contained enhanced O3 and NOy which were anticorrelated with dew point. 

Mar 10:  Third Hong Kong Local Flight

Flight 11 Summary  – Hong Kong Local 3

A flight southward over the South China Sea was planned to look at outflow during a quiescent period.  Model predictions indicated clean condition in the free troposphere with some pollution trapped in the marine boundary layer.


As expected, clean conditions prevailed over much of the flight, and pollution in the boundary layer was encountered at latitudes consistent with outflow from Manila in the Phillippines.  Differences in boundary layer measurements on the outbound and return legs were suggestive of some photochemical evolution with slightly elevated ozone mixing ratios well correlated with NOy and particulates.  Some ship encounters in the boundary layer were also noted in the data.

Mar 9:  Second Hong Kong Local Flight

Flight 10 Summary  – Hong Kong Local 2

A series of in-progress walls were planned along 20N latitude to the east of Hong Kong.  Model predictions indicated aged post-frontal outflow in the middle troposphere should be encountered.


Model predictions were found to be accurate for the middle troposphere.  The P-3B encountered polluted outflow between 7.5-12.5Kft.  Clean conditions were encountered above 12.5Kft.  Pollution encountered in the boundary layer was not predicted, but appeared to be due to ship traffic.  Highly correlated behavior between NOy, SO2, and particulates was observed along with several ship sightings.  NOx/NOy ratios indicated emissions probably too fresh to have been transported from the Asian continent.

Mar 7:            First Hong Kong Local Flight

Flight 9 Summary – Hong Kong Local 1

This flight was intended to sample Asian outflow behind a frontal passage with the P-3B extending northward to the east of Taiwan and crossing the frontal boundary expected near 25N.


Observations included upper tropospheric conditions (15Kft) representative of tropical air to begin the flight (CO-70s, O3-20s).  Polluted conditions were first encountered around 10Kft at 22N (CO-300s, O3-90s).  In the frontal region, cloud modulation of composition was recorded with changes in CO of 75% and doubling of NOy in and out of convective cells.  CO values to the north behind the front were in the high 200-300 range.  On the return to Hong Kong a well defined pollution layer only 1000 ft in thickness was encountered at 9Kft.  Values in this layer for CO were double those encountered in the boundary layer and ozone values were almost quadrupled compared to BL values.  On the last boundary layer leg, a ship plume was encountered that lasted 15 seconds with enhancements in NOy, particles, SO2, and CO2 as well as a significant titration of ozone.

Mar 6: A Press Conference was held for the HK press followed by a tour of the planes.  A reception was hosted by the HK press for the project, consulates and local dignitaries.  Later a reception by the Airport Regal Hotel was hosted for all the TRACE P participants.

Mar 5:  Most of the day was spent badging all the TRACE P people.  The aircraft crew were first so they could get access to the plane as soon as possible.  Items on the C130 were downloaded by the aircraft crew and transported to the lab by HK airport ground crew.  The lab is actually an airline gate that has not been finished, with concrete floors, but with power.  This has proven to be adequate so far.  The PI’s are performing instrument testing, calibrations and repairs on the aircraft when gas bottles and other hazardous materials are used.  The lab has been very useful as a staging area and easy access to PI “blue boxes”, dry ice, and for mixing some chemicals and equipment repair.

The C130 was taxied under airport control to the location of the sea container that was sent in advance and gas bottles and other items needed by the PI’s at the HK site were loaded into the C130.  The C130 taxied back to its parking site next to the P3-B and the DC-8.  The C130 is used as the “storage facility” for the gas bottles during the local flights.

Mar 4: Because of the efforts of the U.S. consulate in HK, the HK government working with representatives in Peking, and the International Affairs Office at NASA HQ working through the state department, necessary information was provided to the Chinese government in Peking that helped in thegranting of permission for the three aircraft to land and operate out of HK.  All three planes arrived Sunday afternoon and parked on the tarmac across a taxiway from active gates for regularly scheduled airplanes.  The airport provides bus transportation between the airplanes and the terminal.

Flight 8 Summary - Guam to HK transit

An intercomparison was planned for the beginning of the flight with both P-3B and DC-8 flying in the marine boundary layer at 500 ft with 2000 ft separation.  This leg was planned for 20 minutes to be followed by another in-progress 20 minute climb to 10,000 ft.  The remainder of the flight included crossing a weak frontal transition and a southbound leg reaching into the South China Sea before heading into Hong Kong.


The intercomparison portion of the flight went well with clean conditions on the boundary layer leg and significant variability on the sounding from 500-10,000 ft.  Observations in the weak frontal transition zone did not show any clear pre- to post-frontal changes in composition.  Entering the South China Sea, persistent pollution was encountered betweeen 8000 ft and the surface with the highest levels of CO, NOy, and particulates yet to be observed.

Mar 2:  Transit Wake Island to Guam.  

The  C130 left the day before to provide support for the DC-8 that had flown directly from Kona to Guam and possibly position itself for getting in early at Hong Kong (HK) to obtain badges before the office closed for the weekend.  Because of ongoing last minute questions from Peking the final authorization for landing in HK was held up and that flight was put on hold.

Flight 7 Summary – Wake Island to Guam transit

This flight was planned to evaluate the southernmost extent of outflow influencing the central North Pacific.  This was to be accomplished through an in-progress wall flown due west to find any pollution layers, a constant altitude leg due south between 19N and 10N latitude to observe the transition from Asian influence to tropical conditions, and another in-progress wall into Guam sampling clean tropical air.


Evidence of Asian outflow on the in-progress wall heading east from Wake Island was not compelling in terms of CO, but a layer of elevated NOy and ozone was located at 18Kft.  Flying at this altitude on the southbound leg revealed a distinct transition to cleaner conditions around 13.5N latitude.  Despite this transition, the in-progress wall into Guam was not dramatically cleaner than conditions flying out of Wake Island further to the north.

Feb 27:  Transit to Wake Island arriving Feb28 IDL-W. 

Flight 6 Summary – Kona to Wake Island transit

As in other transit flights, several in-progress walls were planned for this transit flight.  Model products indicated that some Asian outflow might be encountered just west of Hawaii, but that mostly clean conditions should prevail.


As expected, clean conditions prevailed over much of the flight, but an unexpected layer of pollution was found at 10Kft.  This layer was extremely thin (only 1,000ft) and persisted over the entire distance from Kona, Hawaii to Wake Island.  Wind speeds in this layer were often less than 1 knot signalling this to be a stagnant layer trapped between subsiding air above and a strong inversion at 7Kft.

Feb 26:  All three planes transited from Dryden/Palmdale to Kona, Hawaii for an overnight stop.  During transit flights for the P3-B, primarily they are direct flights with altitude changes from 500 feet to 20,000 ft. with each flight level lasting approximately 20 minutes.  There are also transitions from the top and bottom altitudes at 500 ft./min.

Flight 5 Summary – Dryden/Palmdale  to Kona transit

To provide for several soundings over the eastern Pacific, three in-progress walls were planned for this transit flight.  Model products indicated that some evidence of Asian outflow might be found somewhere between the west coast and Hawaii.


Fairly clean conditions were encountered during this flight; however, a distinct layer was encountered on the second in progress wall between 12.5-13.5Kft.  This layer contained elevated concentrations of CO, NOy, and PAN and was located in the region of model-predicted outflow.

Feb 24:  The P3-B flew from Wallops Flight Facility (WFF) to Dryden to team up with the DC-8 and from there to start the transit flights to Hong Kong.  The P3-B was two days late leaving WFF due to a fuel leaks.  The P-3B was diverted from Edwards AFB (Dryden) to Palmdale, due to runway repairs.  Palmdale is an air force “skunk works” facility that as it turns out is closer to the hotel in Lancaster. The C130 transited to Dryden the day before on Feb 23rd , loaded  DC-8 spare parts and other gear and proceeded the next morning to Palmdale before the runway closed.

Flight 4 Summary - WFF to Palmdale transit (note: Flights 1,2,and3 were test flights conducted at WFF during integration):

While there were no focused objectives for this transit, several notable observations were made:

Extremely low NOy values (tens of pptv) were encountered early in the flight

The middle of the flight was dominated by the presence of severe thunderstorms forcing the aircraft to divert to the south.  Lightning activity was strong based on stormscope detections too numerous to count.  Unfortunately, the aircraft was forced to pass upwind of the storms.  Only one occasion occurred where a handful of lightning strikes occurred upwind of the aircraft.  Shortly thereafter, NO values in excess of 500 pptv were encountered.

As expected from ECMWF predictions, an intrusion of stratospheric air was encountered over the southwest US with ozone values above 200 ppbv between 20-25Kft.  Clear-air turbulence was also encountered within stratospheric air (110-120 ppbv ozone) which may have contributed to enhanced mixing of stratospheric and tropospheric air.

2/17/01 -  Test flights 2 and 3 were conducted this past week, Tues. 13feb01 and Sat. 17feb01.  

Although there were a few operational problems encountered on the second flight, all project and instrument PI's on the P3-B indicated they were "mission ready".  Some exceptions are detailed later in this update.   

The flight Saturday  was a five hour flight that started at 3:00pm Local time to provide OH and actinic flux background measurements during the night portion of the flight.  Flight altitudes were between 500 and 20,000 ft.  Maneuvers were conducted to support the TAMMS calibrations with an extended constant speed leg at 20,000 ft.

At the expense of 150 lbs. of air conditioner added to the cargo area, Kondo's NO2 converter temperature was maintained within the desired operating temperature with ample reserve and  NO2 measurements were successfully recorded for the first time on the third flight.   

There are some exceptions to the general success of instrument operations. 

1.        Final installation of Clarke's FSSP probe will be on 20feb01, checked out on the ground and an engineering check flight (ECF) performed on 21feb01.   

2.        The initial installation of the satcom antenna up forward on the P3-B was unsatisfactory for either sending or receiving voice communications on the second flight.  The antenna had been relocated midway on the aircraft, but the total installation could not be completed before the third flight.  A technician from the manufacture of the satcom system will be at WFF on 20feb01 to perform a final installation check.  It will be tested during the ECF.

3.  A small fin will be added to the back of Vay's CO2 probe to eliminate a vibration that occurs at certain aircraft speeds on 20feb01 and be tested during the scheduled ECF.   All PI "blue boxes" are scheduled to be ready for loading on the C130 on Tuesday, 20feb01.

2/10/01 -The first instrument test flight occurred Friday 2/9/01 at 11:00am lasting for approximately three hours.

For a first test flight, it was considered successful.  Most  "bugs" or problems were fixed by the PI's either in flight or shortly after returning to WFF.  A more detailed operational status report for each instrument will be provided after the second test flight scheduled for Tuesday, 2/13/01 at 3:00pm and lasting for 3.5 hours.  The flight will extend into darkness to test the response of the spectroradiometer and the OH measurement.

The Engineering Check Flight (ECF) was conducted on Thursday the day before the first test flight with all the instruments in place but unpowered.  Only the aircraft crew and the two structural engineers were on the flight.  Aircraft maneuvers and speed exceeded expected mission profiles.  Only two minor discrepancies were noted in the ECF closeout memo.

Two installations are still in progress: air conditioning for Kondo's NO2 converter and Clarke's FSSP wing probe.  The air conditoner should be completed before the third test flight scheduled for Friday, 2/16/01 and steps are being taken to insure the FSSP probe is installed before departure from WFF


2/3/01 -Integration of all instruments on the P-3B is near completion.  

Most instruments are powered and check out so far has been successful.  A special cooling connection for Kondo's rack is being constructed and will be available for the second test flight.   The P-3B hazard analysis review was held on Thursday and the Mission Readiness Review was held  Friday.  

A few action items resulted from the meeting.  They primarily were in regards to approval of instrument installations on the aircraft.   The Engineering check flight is scheduled for Thursday 08feb01 and the first Test flight is on Friday 09feb01.  Refer to the P-3B Integration Schedule for more detail.

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