**[NACP Synthesis Project:]{.underline} \"Spatial and Temporal
Distributions of Sources for non-CO~2~ Greenhouse Gases (CH~4~, CO,
N~2~O) over North America\"**

*Organized by: S. C. Wofsy, Harvard University; J. Eluszkiewicz, AER;
A.Andrews, NOAA-ESRL*

**[The above synthesis project, recently funded by NASA,
is]{.underline}** inviting you to participate. We will collect
comprehensive data for concentrations and fluxes of **CH~4~, CO,** and
**N~2~O**, and develop and publish top-down estimates of fluxes from
North America, seasonally/spatially resolved.

***[Motivation for the synthesis]{.underline}***

The non-CO~2~ greenhouse gases (CH~4~, CO, N~2~O) are a major focus for
the NACP (Harriss and Wofsy, 2001). CH~4~ and N~2~O together account for
almost half of the radiative forcing attributed to CO~2~ (Fig. 1).
Measurements of CO are also integral to the NACP, since CO is a tracer
for CO~2~ emitted from mobile sources and biomass fires \[e.g. Gerbig et
al. 2003; Geels et al., 2004\] and CO helps to define factors
influencing tropospheric O~3~, another key contributor to radiative
forcing (Fig. 1).

A wealth of data has been collected by NACP and other projects defining
the spatial and temporal distributions of these gases, as summarized in
part in Table 1. Several papers have derived bottom-up inventories
\[e.g. Kort et al., 2008; Chen et al., 2006 (CH~4~); Hirsch et al., 2006
(N~2~O); Olivier et al., 2005\], but these efforts have not been
combined or utilized in a comprehensive top-down analysis. A
comprehensive data base containing the large number of recent
observations is needed for top-down validation and improvement of
emission inventories.

![](media/image1.jpeg){width="6.002083333333333in"
height="4.283333333333333in"}

***This is therefore an ideal time to carry out the proposed synthesis
of data for non-CO~2~ Greenhouse Gases (CH~4~, CO, N~2~O) over North
America to produce definitive top-down analysis of their sources in
North America.***

*Table 1: Data sets for non-CO~2~ Greenhouse Gases (partial,
preliminary)*

A. On-going monitoring

  ------------------ ----------------- ----------------- -----------------
  **Organization**   **Altitude**      **Measurement     **Locations**
                                       type**            

  Environment Canada Surface stations  Continuous and    Alert, Alberta,
                                       flasks            Fraserdale,

  NOAA Tall Towers   Profiles in the   Weekly, Daily     WLEF, Waco,
                     lowermost PBL     flasks; CO~2~,    Maine, 4 others
                                       CO, CH~4~;        
                                       continuous        
                                       starting 2007     

  NOAA aircraft      0-7 km (many,     Monthly, Weekly;  MA, NH, WLEF, MA,
                     starting 2000)    flasks            CO, others

  AmeriFlux          Surface stations  Continuous (CO,   MA
                                       CO~2~))           
  ------------------ ----------------- ----------------- -----------------

B. Aircraft Campaigns

  -------------------- ----------------- ----------------- -----------------
  **Mission**          **Altitude**      **Measurement     **Locations**
                                         type**            

  COBRA-2003           0 - 10 km, ca.    Continuous,       Northern US and
                       400 profiles      flasks            Southern Canada,
                                                           summer

  INTEX-A (2004)       0 - 10 km, ca.    Continuous,       Northern US and
                       200 profiles      flasks            Southern Canada,
                                                           summer

  COBRA-2004           0 - 8 km, ca. 900 Continuous,       NE US and SE
                       profiles          flasks            Canada, summer

  CLASSIC (2007)       0 - 8 km          Continuous,       Midwest US
                                         flasks            

  START08/pre-HIPPO;   0 -- 14 km        Continuous,       US Midwest,
  ARCTAS                                 flasks; DC-8,     central/arctic
                                         HIAPER            Canada, Alaska
  -------------------- ----------------- ----------------- -----------------

***[Goals of the Synthesis activity]{.underline}***

**1.** Develop a comprehensive data base in uniform, accessible format.

**2.** Create a set of bottom-up inventories with best possible spatial
and temporal resolution, disaggregated by source type.

**3.** Coordinate and/or undertake top-down validation and improvement
of emissions inventories to create a set of synthesis products at
various scales from regional to continental, defining emissions of these
gases in the NACP domain.

**The synthesis products will be designed to address societal needs for
better quantitative knowledge of greenhouse gas sources in N. America.**

The data products of recent and ongoing programs will be the foundation
for the results from the synthesis, and the scientists active in these
projects will be key collaborators. Each collaborator will have an
ownership stake in the products, engendered by participation in the
workshop and in the work of the synthesis, and in authorship of the
published products.

***[Schedule of Proposed activities]{.underline}***

-   *November, 2008*: Three-day Workshop with 20 participants at Harvard
    to plan the study. .

-   *September 2008-January, 2008*: Data assembly and preparation of WRF
    winds at AER, BRAMS winds at Harvard.

-   *January, 2009-July, 2009*: Inversion studies.

-   *July, 2009*: Workshop with 25 participants at Harvard to assess the
    analyses, and set reporting and publication activities.

-   *August-December, 2009*: Preparation of publications and reports.

-   *March, 2009*: Publications complete.

**Total** duration 18 months.

***[Attendees: see Appendix]{.underline}***

***[Deliverables:]{.underline}***

1.  Comprehensive data base, served at a major data archive center.

2.  Scientific papers devoted to analysis of the budgets of non-CO~2~
    greenhouse gas emissions from North America. These papers will have
    multiple authors (or a group/committee author) representing a broad
    cross-section of the scientific community and will deal with issues
    including sampling, analysis, attribution, uncertainties, and
    development of measurement recommendations.

3.  NACP/CCSP Special Report, written for decision support and for the
    public, discussion US and North American contributions to non-CO~2~
    greenhouse gas emissions during the period 2000-2007. It will
    include assessment of the source magnitudes, discussion of
    attribution, and recommendation for sampling and measurement
    priorities for the future.

***[References]{.underline}***

Chen, Y.-H., and R. G. Prinn (2006), Estimation of atmospheric methane
emissions between 1996 and 2001 using a three dimensional global
chemical transport model, *J. Geophys. Res., 111*, D10307,
doi:10.1029/2005JD006058.

Eluszkiewicz, J., T. Nehrkorn, S. C. Wofsy, D. Matross, C. Gerbig, J. C.
Lin, S. Freitas, M. Longo, A. E. Andrews, W. Peters, and B. Daube
(2008), Regional Simulations of Tower-Based and Airborne CO~2~
Measurements With the Coupled Weather Research and Forecasting/
Stochastic Time-Inverted Lagrangian Transport/Vegetation Photosynthesis
and Respiration Models, *(in review) J. Geophys. Res.*

Geels, C., S. C. Doney, R. Dargaville, J. Brandt, J. H. Christensen
(2004) Investigating the sources of synoptic variability in atmospheric
CO~2~ measurements over the Northern Hemisphere continents: a regional
model study Tellus B 56 (1) , 35--50 doi:10.1111/j.1600-889.2004.00084.x

Gerbig, C., J. C. Lin, S. C. Wofsy, B. C. Daube, A. E. Andrews, B. B.
Stephens, P. S. Bakwin, and C. A. Grainger, Towards constraining
regional scale fluxes of CO2 with atmospheric observations over a
continent: 1. Observed Spatial Variability, *J. Geophys. Res.*
*108,*. D24, 4756 (14 pp) , 2003.

Hirsch, A. I., A. M. Michalak, L. M. Bruhwiler, W. Peters, E. J.
Dlugokencky, and P. P. Tans (2006), Inverse modeling estimates of the
global N2O surface flux from 1998--2001, *Global Biogeochem. Cycles,
20*, GB1008, doi:10.1029/2004GB002443.

Kort, Eric A., J. Eluszkiewicz, B. B. Stephens, J. B. Miller, C. Gerbig,
T. Nehrkorn, B. C. Daube, J. O. Kaplan, S. Houweling, and S. C. Wofsy
(2008), Emissions of CH4 and N2O over the United States and Canada based
on a receptor-oriented modeling framework and COBRA-NA atmospheric
observations, *submitted to GRL*

Olivier, J.G.J., Van Aardenne, J.A., Dentener, F., Ganzeveld, L. and
J.A.H.W. Peters (2005), Recent trends in global greenhouse gas
emissions: regional trends and spatial distribution of key sources. In:
"*Non-CO2 Greenhouse Gases (NCGG-4)",* A. van Amstel (coord.), page
325-330. Millpress, Rotterdam, ISBN 90 5966043 9.

**Appendix.** List of potential participants.

PIs: Janusz Eluszkiewicz

Steven C. Wofsy

NOAA collaboration leader; Arlyn E. Andrews

1.  Elliot Atlas

2.  Don Blake

3.  Lori Bruhwiler

4.  Mous Chahine

5.  Patrick Crill

6.  Ed Dlugokencky

7.  James W.Elkins

8.  Marc Fischer

9.  Wei Min Hao

10. Adam Hirsch

11. Dale Hurst

12. Daniel Jacob

13. Jed Kaplan

14. John C. Lin

15. Wallace McMillan (AIRS)

16. Anna Michalak

17. John Miller

18. Steve Montzka

19. Colm Sweeney

20. Margaret Torn

21. Marek Uliasz

22. Katey Walters

23. Paul Wennberg

24. Doug Worthy