A53Q-0445 - Assessing the Suitability of MOZAIC Soundings of Trace Gases in the Lower Troposphere for Chemical Transport Model Evaluation

Introduction

Morgan L. Silverman1,2, James Szykman3, James H. Crawford2, Andreas Volz-Thomas4, Philippe Nedelec5, Jean-Pierre Cammas5

1Science Systems and Applications Inc., Hampton, VA, 2Science Directorate, NASA Langley Research Center, Hampton, VA , 3National Exposure Research Laboratory, U.S. EPA, ORD, Research Triangle Park, NC, 4IEK-8, Forschungszentrum Jülich, Jülich, Germany, 5Université de Toulouse-CNRS, Toulouse, France

Summary and Future WorkSince the mid-90’s, vertical profiles of reactive gases into and out of major airports have been measured by the MOZAIC (Measurements of OZone and water vapor on Airbus In-service airCraft - currently part of the European program

In-service Aircraft for a Global Observing System (IAGOS) http://www.iagos.fr/web/) program. Recent interest in using MOZAIC data to evaluate regional chemical transport models, such as the Community Multiscale Air Quality Modeling System (CMAQ), raises questions regarding the suitability of the data for this purpose. Specifically, to what degree are aircraft data influenced by aviation emissions along flight paths and how well does the data represent the regional environment at lower altitudes?

A general lack of upper-air chemistry measurements has limited the ability to routinely evaluate CMAQ predictions of O3 concentrations aloft. As a result, most evaluations have focused on surface observations. While such analyses are essential, routine vertical profile data are needed to asses processes such as vertical mixing between the boundary layer (BL) and free troposphere (FT), hemispheric transport, lightning generated NOx, and stratospheric intrusion. Recent efforts have started to evaluate CMAQ’s performance in the FT using data collected from ozonesondes (Eder, et al, 2010).

Existing MOZAIC literature contains an extensive use of upper tropospheric and lower stratospheric data for model evaluation and trends, with limited analyses using the measurements in the lower troposphere, the region of interest for regional model evaluation. Fischer et al. 2006 raises concerns about the representativeness of in-service aircraft trace gas profiles for background conditions. The goal of this study is to assess the representativeness of MOZAIC data.

This analysis characterizes MOZAIC measurements of O3, CO, and NOy in the mid to lower troposphere (<6km). MOZAIC afternoon profiles that span 2002-2004, during June, July, August, and September at major U.S. airports are compared with profile data from the NASA Earth Venture-1 (EV-1) DISCOVER-AQ (Deriving Information on Surface conditions from COlumn and VERtically resolved observations relevant to Air Quality) mission. As part of the first DISCOVER-AQ field mission conducted in July 2011, the NASA P-3B aircraft performed over 250 profiles in the Baltimore-DC region, including one landing at the Baltimore Washington International Airport. These profiles offer comparative observations of O3, CO, and reactive nitrogen in the vicinity of major air traffic patterns, local urban sources, and typical background environments. The NOAA New England Air Quality Study–Intercontinental Transport and Chemical Transformation (NEAQS-ITCT) campaign also provides a useful temporal comparison to MOZAIC.

(Fischer, H., M. Lawrence, Ch. Gurk, P. Hoor, J. Lelieveld, M. I. Hegglin, D. Brunner, and C. (2006), Model simulations and aircraft measurements of vertical, seasonal, and latitudinal O3 and CO distributions over Europe, Atmos. Chem. Phys., 6, 339-348.)

• CMAQ [O3] distributions are low at ~3-5 km compared to MOZAIC but become higher than MOZAIC as the [CO] concentrations increase below 2 km.

• CMAQ and MOZAIC [O3] distributions in the lowest few 100 meters agree well.• [CO] is overestimated in CMAQ and has greater variability in the BL compared to

MOZAIC [CO].

• [O3] distributions are low at ~3-5 km compared to MOZAIC, but to a lesser degree than descending flights.

• CMAQ and MOZAIC [O3] distributions in the lowest 2 km agree well but are a bit high closer to the surface.

• CMAQ [CO] distributions better aligned with variability seen in MOZAIC [CO].

MOZAIC and CMAQ O3 and CO Profiles Philadelphia Airport (June, July, August 2006)Descending Flights(35% 3pm, 53% 4pm)

Ascending Flights(38% 6pm, 43% 7pm)

MOZAIC/IAGOS in-service trace gas profiles provide a high quality data set for use in regional chemical transport model evaluation. Good agreement in the distribution of O3, CO, and NOy exists between MOZAIC, NEAQS-ITCT, and DISCOVER-AQ datasets despite temporal and spatial differences. From these comparisons we have confidence that MOZAIC data in the lower troposphere (<6 km) is representative of the urban environment and is likely not influenced by aircraft flight paths and emissions.

Future DISCOVER-AQ studies over California and Houston will provide opportunities to compare observations on approach to major airports with their surrounding metropolitan areas. These observations will again be compared with historical MOZAIC profiles, but the potential for newer and possibly concurrent observations from IAGOS would be ideal.

Using the Aircraft Communications Addressing and Reporting System (ACARS) and the Aircraft Meteorological Data Relay (AMDAR) we would like to characterize boundary layer changes in conjunction with MOZAIC descents and ascents.

• MOZAIC is a European partnership between scientists, Airbus and commercial airlines that began measuring ozone and water vapor from commercial aircraft in 1994.

• 5 long-haul aircraft with trace gas and meteorological measurements of O3, CO, H2O, NOy, T, P, RH, wind speed and direction.

• MOZAIC is now part of IAGOS (In-Service Aircraft for the Global Observing System), a new European initiative to measure tropospheric and lower stratospheric air quality and greenhouse gases with instruments based on commercial aircraft.

• Goal of IAGOS: Over the next decade install monitoring equipment on 10-20 commercial aircraft, based around the world.

DATA

North American Airports with available MOZAIC vertical profiles of trace gases

•DISCOVER-AQ is a four-year airborne field study focused on improving the interpretation of satellite observations to diagnose near-surface conditions influencing air quality.

•In situ profiles from the NASA P-3B research aircraft were routinely collected during July 2011 over six Maryland Department of the Environment ground stations (Aldino, Beltsville, Edgewood, Essex (closest to BWI), Fairhill, and Padonia) in the Baltimore-DC metropolitan area.

•The map to the left shows the P-3B flight track in yellow. Circles indicate the location of profiles over ground sites. One flight collected observations on approach and landing at BWI at the beginning of the study. That flight is shown in red.

3. NASA Deriving Information on surface conditions from COlumn and VERtically resolved observations relevant to Air Quality (Discover-AQ)

2. NOAA New England Air Quality Study Intercontinental Transport and Chemical Transformation program (NEAQS-ITCT 2004)

• NEAQS-ITCT was conducted as part of the larger trans-Atlantic ICARTT study during July and August 2004.

• The study focused on air quality along the Eastern Seaboard and transport of North American emissions into the North Atlantic.

• In situ measurements were collected across New England and the Ohio Valley by the NOAA WP-3D aircraft.

• The map to the left shows the WP-3D flight tracks color coded by flight day. Only the data within the black box was analyzed in this study to focus specifically along the major Northeast corridor. (Fehsenfeld et al. 2006)

1. Measurement of Ozone, water vapour, carbon monoxide and nitrogen oxides by Airbus in-service airCraft (MOZAIC

)

Acknowledgements

I would like to acknowledge Christian Hogrefe and Brian Eder of the U.S. EPA for providing CMAQ results. The U.S. EPA collaboration on this effort was funded through the Air, Climate, and Energy Research Program Task 244 – Use of profile and total column measurements (Commercial aircraft, satellite, remote sensing and ground based remote sensing observations) for Air Quality Modeling and Analysis and Development of an Integrated Monitoring Approach – Air Quality Above the Lowest Part of the Troposphere.

MOZAIC O3, NOy, and CO Profiles Descending Flights for Eastern U.S. Airports (June-Sep 2003-2004 )

NEAQS-ITCT• Higher O3 distributions in the NEAQS-ITCT

data than MOZAIC. The ITCT data occurred during peak O3 months, July and August, while MOZAIC includes June and September for added robustness.

• The NOy distribution median values differ by 2 ppb. These levels aren’t sufficiently different from MOZAIC and are small enough to rule out large influence by the aircraft in the lower troposphere (<6 km). Can’t say anything about near surface (<1 km).

• CO compares reasonably well. Extreme values are most likely due to smoke from Canadian forest fires.

DISCOVER-AQ• DAQ consistently shows higher O3 values

than MOZAIC and ITCT. 2004 was a very clean O3 year.

• Reductions in point sources since 2004 could explain lowering of NOx levels.

• CO values are still very consistent.

• BWI Approach: Shows coincident increases in NOy and CO concentrations below 1km, reflective of an urban (mobile source) influence. Approximately 1/3 of NOy is NO2 giving an upper bound on possible titration impacts at the surface.

10th 25th 50th 75th 90thJuly/Aug 2004 All MOZAIC

MOZAIC• Consistency between MOZAIC 25th

and 75th percentile in all species with the exception of Atlanta NOy. This consistency gives us the sense that precise co-location isn’t necessary.

• July/Aug 2004: When looking at all the MOZAIC profiles in July/Aug 2004 EWR-JFK-IAD-PHL compare much closer to the NEASQ-ITCT data than when using the smaller extended dataset that had matching NOy data.

Beltsville

Padonia

Fairhill

Aldino

EdgewoodEssex

BWIApproach

* For additional information, contact morgan.l.silverman@nasa.gov

AGU Fall Meeting 2012(Fehsenfeld, F. C., et al. (2006), International consortium for atmospheric research on transport and transformation (ICARTT): North America to Europe – Overview of the 2004 summer field study, J. Geophys. Res., 111, D23S01, doi:10.1029/2006JD007829.)

O3 NOy CO