ACOM Director's Message

I am pleased to present the 2017 Laboratory Annual Report (LAR) for the Atmospheric Chemistry Observations and Modeling (ACOM) Laboratory. This has been a very busy year for the Laboratory as demonstrated by the exceptional science and community service highlighted in the following sections.

The mission of ACOM is to develop predictive capability for atmospheric composition, through advances in understanding of chemistry and related processes. Our research emphasizes the quantitative integration of observations and modeling across scales to identify impacts on air quality, weather and climate, and to assess the role of chemistry within the coupled Earth system.

At the end of last year, ACOM embarked on a period of strategic planning motivated by the recommendations of the 2016 National Academies Science (NAS) report on the Future of Atmospheric Chemistry Research. Under a new, overarching, theme for ACOM of building predictive capability for atmospheric composition, three new initiatives emerged from the many discussions. These centered on quantifying atmospheric reactive carbon chemistry at the molecular level, cross-scale prediction of atmospheric composition and air quality hazards, and atmospheric chemistry in the coupled Earth system. In February 2017, NCAR convened a ‘Blue Ribbon Panel’ (BRP) of community leaders to advise on the extent to which these Initiatives and the NCAR chemistry program were positioned to respond to the NAS recommendations. The report emerging from the BRP includes some clear recommendations for NCAR. It was very supportive of creating a strong chemistry program that is balanced between observations and modeling. The Panel particularly liked the central ideas behind the reactive carbon and new Community Chemistry Model initiatives, as ways of leading and engaging the community. They also called out the Whole Atmosphere Community Climate Model (WACCM) as an ACOM success story. Implementation of the BRP recommendations is currently under discussion between NCAR and NSF in the light of the current budget and future outlook.

The LAR follows the structure of the NCAR Strategic Plan, with sections devoted to research and community support that address the NCAR Imperatives. ACOM activities focused on observations (Imperative 2) and modeling (Imperative 3) also contribute to fundamental research (Imperative 1), often through integrative efforts, including data assimilation. On the observations side, state-of-the-art atmospheric chemistry instrumentation remains a Lab priority, as exemplified in the development of the High-Resolution Time-of-Flight version of the Trace Organic Gas Analyzer (TOGA) instrument (Section 2A), the GV Pod Inlet Test Project (Section 2D), and fundamental studies in the ACOM Environmental Chamber (Section 1F). For community modeling, continuing enhancement in capability is described for WRF-Chem (Section 3A) and WACCM (Section 3B). ACOM scientists are also very active in every stage of chemistry field campaign development, from early planning (e.g. Section 1A - Asian Summer Monsoon: Transport from the Intensely Polluted Troposphere to the Stratosphere), to deployment (e.g. Section 2B - NASA ATom mission), through data analysis of past observations (e.g. Section 1C - Whiteface Mountain Coordinated Cloud Chemistry Investigation).

The wider atmospheric sciences community is very important to the ACOM mission, and our scientists work closely with national and international researchers, teachers, students and decision makers, providing intellectual leadership and support for measurement capabilities, laboratory and field experiments, and atmospheric chemistry models. Understanding the factors determining air quality and communicating these to the various stakeholders is a good example of ACOM collaborative research that has wide societal impact. Research in this area includes findings from the FRAPPÉ and DISCOVER-AQ field Campaigns (Section 5A) and the satellite tracking of wide-spread pollution from western U.S. wildfires (Section 5B). The Lab is also pleased to host U.S. and international visitors for both short and long-term collaborations, in addition to organizing community workshops and conferences. Over the past year, these have included the ACCORD Fire Data Analysis Workshop at NCAR that engaged primarily early-career scientists in data-mining of past campaign measurements impacted by fire emissions (Section 2E), and the Atmospheric Composition and the Asian Monsoon (ACAM) Workshop in Guangzhou, China (Section 6B). The ACAM Workshop was also accompanied by a student training school (Section 6A) led by ACOM scientists.

The year ahead will be busy as ACOM positions itself to implement the recommendations of the recent NAS and BRP reports. This will be accomplished in close collaboration with the other NCAR Labs, UCAR programs and the wider research community in atmospheric chemistry and composition.

David Edwards