Grantee Research Project Results

2010 Progress Report: Constraining ammonia emissions and PM2.5 control efficiencies with a new combination of satellite data, surface observations and adjoint modeling techniques

EPA Grant Number: R834559
Title: Constraining ammonia emissions and PM2.5 control efficiencies with a new combination of satellite data, surface observations and adjoint modeling techniques
Investigators: Henze, Daven K
Institution: University of Colorado at Boulder
EPA Project Officer: Chung, Serena
Project Period: May 1, 2010 through April 30, 2013 (Extended to April 30, 2014)
Project Period Covered by this Report: May 1, 2010 through April 30,2011
Project Amount: $249,942
RFA: Novel Approaches to Improving Air Pollution Emissions Information (2009) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Air

Objective:

The project goal is to reduce existing uncertainties in current estimates of NH₃ emissions in order to better characterize and control distributions of fine particulate matter (PM_2.5) and reactive nitrogen. The specific research objectives are to:

Quantify the magnitude and variability, both geographical and seasonal, of US NH3 emissions at a high spatial resolution.
Provide detailed estimates of PM_2.5 control efficiencies and how they will evolve owing to regulations that alter key balances among inorganic particulate species.

Progress Summary:

Progress has been made in utilizing remote sensing observations to understand distributions of NH₃. Initial efforts focused on characterization of retrievals from the TES satellite instrument in terms of instrument sensitivity, accuracy and detection limits (Shephard, et al., submitted). Model simulations were performed to determine the instrument detection limit (~1 ppbv) and the bias (also ~+1 ppbv) of the retrieval. TES observations then were compared to measurements of NH₃ from CAMNet surface monitoring sites, demonstrating the ability of TES to capture both spatial and temporal variability in NH₃ concentrations (Pinder, et al., in press). Global retrievals of NH₃ were processed from TES for 4 months of the year over 4 years, identifying interesting trends and regions for future study through comparison to equivalent values from GEOS-Chem (Shephard, et al., submitted).

The validated NH₃ retrievals have subsequently been used to provide initial constraints on NH₃ sources. Comparisons of modeled NH₃ values to TES have been performed for April, July and October over North America for the years 2006-2009. The NH₃ simulations after emissions optimization are compared to surface observations from the AMoN network of passive monitoring sites in order to assess the fidelity of the emissions constraints. Optimized emissions scaling factors also have been applied to the emissions inventory for the regional air quality model CMAQ, and the model results using the emissions that are constrained by NH₃ from TES can give better agreement with the AMoN data than the base case models. The overall finding is that NH₃ emissions appear to be broadly underestimated, though significant spatial and seasonal variability in this feature are evident.

Future Activities:

Future work will look at impacts of NH₃ emissions constraints on nitrogen deposition and aerosol concentrations. Also, a high-resolution, nested adjoint for GEOS-Chem has been developed and tested for a tagged CO simulation over Asia; these capabilities soon will be ported to the full chemistry adjoint to further study North America to facilitate higher resolution top-down constraints.

Journal Articles on this Report : 2 Displayed | Download in RIS Format

Publications Views
Other project views:	All 49 publications	10 publications in selected types	All 10 journal articles

Publications
Type	Citation	Project	Document Sources
Journal Article	Pinder RW, Walker JT, Bash JO, Cady-Pereira KE, Henze DK, Luo M, Osterman GB, Shephard MW. Quantifying spatial and seasonal variability in atmospheric ammonia with in situ and space-based observations. Geophysical Research Letters 2011;38(4):L04802 (5 pp.).	R834559 (2010) R834559 (2011) R834559 (2012) R834559 (Final)	Full-text: Wiley-Full Text HTML Exit Abstract: Wiley-Abstract Exit Other: Wiley-Full Text PDF Exit
Journal Article	Shephard MW, Cady-Pereira KE, Luo M, Henze DK, Pinder RW, Walker JT, Rinsland CP, Bash JO, Zhu L, Payne VH, Clarisse L. TES ammonia retrieval strategy and global observations of the spatial and seasonal variabiity of ammonia. Atmospheric Chemistry and Physics 2011;11(20):10743-10763.	R834559 (2010) R834559 (2011) R834559 (2012) R834559 (Final)	Full-text: ACP-Full Text PDF Exit Abstract: ACP-Abstract Exit

Supplemental Keywords:

ammonia, emissions, inverse modeling, adjoint sensitivity, environ-mental policy, air quality regulations, fine particulate matter, aerosols, remote sensing, data assimilation, 4D-Var, public health, eutrophication

Progress and Final Reports:

Original Abstract

The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.