Monthly Technical Report PROJECT TITLE

Surface Measurements of Trace Gases in Support of DISCOVER-AQ in Houston in Summer 2013

PROJECT # 13-024

PROJECT PARTICIPANTS

University of Maryland College Park NOAA Air Resources Laboratory

DATE SUBMITTED

10/8/2013

REPORTING PERIOD

From: September 1, 2013 To: September 30, 2013

REPORT # 7

University of Maryland

Invoice # #8

Amount $11,691.20

A Financial Status Report (FSR) and Invoice will be submitted separately from each of the Project Participants reflecting charges for this Reporting Period. I understand that the FSR and Invoice are due to the AQRP by the 15th of the month following the reporting period shown above. Detailed Accomplishments by Task (Include all Task actions conducted during the reporting month.) Teams at University of Maryland and NOAA’s Air Resources Laboratory completed the field deployment in September 2013 during DISCOVER-AQ in Houston. The following tasks have been accomplished:

(1) Completed the data collection at the Galveston and Manvel Croix sites. (2) Completed further testing and calibrations of the instruments in the field. (3) Submitted the preliminary data files to the DISCOVER-AQ data archive. (4) Transported the instruments from the field back to the laboratory for further testing or

calibrations, if needed. Preliminary Analysis (Include graphs and tables as necessary.)

We tried to compare measurements at the Galveston and Manvel Croix Sites with the same measurements made on the P-3B. In order to make meaningful comparisons, we limited the P-3B data made only at the bottom of each spiral near each site and have applied the following two criteria: (1) P-3B pressure altitude is below 1000 ft, and (2) the longitude/latitude of the P-3B are within +/-0.02˚ (roughly ~+/- 2 km) of the site location. Figure 1 shows the ozone mixing ratio along the flight track and relative locations of the Galveston and Manvel Croix sites during the flight on September 13, 2013.

Figure 1. Mixing ratios of ozone measured on P-3B in Flight 09/13/2013 during the DISCOVER-AQ field study in Houston. Comparison of the surface ozone mixing ratios at the Galveston site with the P-3B measured ozone mixing ratios shows that both measurements are very close to each other (Figure 2). This good agreement between the surface and aircraft ozone measurements is mainly due to the missed approached P-3B conducted at the Galveston Airport at the bottom of each spiral. On September 6, 12, 13, and 14, typical morning ozone titration was observed due to high levels of NOx (Figure 3-4). On September 13, we observed high ozone mixing ratio up to 76 ppbv at the surface.

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Figure 2. Time series of ozone mixing ratios measured by the UMD/NOAA group and TCEQ as well as by P-3B at the bottom the spiral at the Galveston site during DISCOVER-AQ field study in Houston.

Comparisons of the surface and aircraft measured NO/NO2/NOy at the Galveston site show that both data sets agree well in general (Figure 3-5), although we will need other measurements (e.g., surface wind data, vertical gradients of these species) in order to interpret the detailed variations in each data set.

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Typical morning O3 titration with high NOx

Figure 3. Time series of NO2 mixing ratios measured by the UMD/NOAA group and by the P-3B at the bottom of the spirals at the Galveston site during the DISCOVER-AQ field study in Houston. Two instruments on the P-3B measured NO2: one based on chemiluminescence (CL) and the other based on laser induced fluorescence (LIF).

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Figure 4. Time series of NO mixing ratios measured by the UMD/NOAA group and by the P-3B at the bottom of the spirals at the Galveston site during the DISCOVER-AQ field study in Houston.

Figure 5. Time series of NOy mixing ratios measured by the UMD/NOAA group and by the P-3B at the bottom of the spirals at the Galveston site during the DISCOVER-AQ field study in Houston.

As to the SO2 comparison, it seems that [SO2] measured on the P-3B is generally higher than the surface [SO2] at the Galveston site, especially when the SO2 level were high (Figure 6). One explanation is the SO2 mixing ratios were higher in the air mass aloft. We will also double check the calibration of the instrument and will compare the final data when they are available.

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Figure 6. Time series of SO2 mixing ratios measured by the UMD/NOAA group and by the P-3B at the bottom of the spirals at the Galveston site during the DISCOVER-AQ field study in Houston. At the Manvel Croix site, the surface ozone mixing ratios agree well with the P-3B measurements (Figure 7), which is very similar to the comparison at the Galveston site. This suggests that by the time when the P-3B flew over the Manvel Croix site (usually during the mid-day), the mixing layer was well mixed.

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• P3B [SO2] is generally higher than the ground [SO2].

Figure 7. Time series of O3 mixing ratios measured by TCEQ on the surface and by the P-3B at the bottom of the spirals at the Manvel Croix site during the DISCOVER-AQ field study in Houston.

For the NO2, there is general good agreement between the surface and aircraft measurements, although the P-3B [NO2] is usually less than the ground [NO2], indicating that there might be strong vertical gradients because of the surface NO2 emissions. Further investigation will be conducted when the final data are available.

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Figure 8. Time series of NO2 mixing ratios measured by the UMD/NOAA group and TCEQ on the surface and by the P-3B at the bottom of the spirals at the Manvel Croix site during the DISCOVER-AQ field study in Houston. Two instruments on the P-3B measured NO2: one based on chemiluminescence (CL) and the other based on laser induced fluorescence (LIF). Data Collected (Include raw and refine data.) Data were collected between August 31 and September 27, 2013. Preliminary data files with 10-second averaged NO2 measurements at the Manvel Croix site and 1-minute averaged NO, NO2, NOy, O3 and SO2 at the Galveston site have been submitted to the DISCOVER-AQ data archive, so research groups that are interested in the measurements at the two sites can take a look at our data. Identify Problems or Issues Encountered and Proposed Solutions or Adjustments None. Goals and Anticipated Issues for the Succeeding Reporting Period

(1) Further analysis of the calibrations/tests done in the field to get the final numbers for the instrument response factors and conversion coefficient (for the NO2 photolytic converter).

(2) Finalize the data and submit the data to the DISCOVER-AQ data archive. (3) Further compare our ground measurements to the NASA P-3B measurements when the

airplane was doing the spirals at the Manvel Croix and Galveston sites.

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Detailed Analysis of the Progress of the Task Order to Date (Discuss the Task Order schedule, progress being made toward goals of the Work Plan, explanation for any delays in completing tasks and/or project goals. Provide justification for any milestones completed more than one (1) month later than projected.) We successfully collected data at the Manvel Croix and Galveston sites in September 2013 during the DISCOVER-AQ study in Houston. Everything regarding the Task Order schedule and progress is going well. There were no delays in completing tasks and project goals during this reporting period. Submitted to AQRP by: _____Xinrong Ren_________________________ Principal Investigator: ______ Xinrong Ren ________________________ (Printed or Typed)