Exploiting Large-scale Aircraft Measurements to Evaluate and Constrain Vertical Profiles and Speciation in Aerosol Forecasting and Analysis
Abstract
One of the big challenges in aerosol analysis and forecasting is that most of the readily available data for validation and assimilation resolve neither the vertical profile nor the speciation of aerosol. At the same time, models are becoming more complex as schemes for e.g. nitrate, ammonium and secondary organic aerosol (SOA) are added, with little observational constraint on the additional degrees of freedom.
Large-scale aircraft campaigns such as the recent NASA ATom provide an exciting opportunity to evaluate and constrain these aspects of complex aerosol models in much greater detail than is possible with traditional remote sensing or surface measurements. Using the NASA DC-8, ATom spans a large geographical area over multiple seasons, with extensive vertical profiling and a host of in-situ measurements of both aerosol and trace-gas composition. We use measurements of aerosol concentration and speciation from the high-resolution time-of-flight aerosol mass spectrometer (HR-ToF-AMS) and single-particle soot photometer (SP2) to evaluate global analyses and forecasts for this period from the Copernicus Atmosphere Monitoring Service (CAMS) operated by ECMWF on behalf of the European Commission. This allows us to gain additional insight into the evolution of the operational and reanalysis products compared to what can be obtained from conventional data sources, which can be used to guide future improvements alongside the usual focus on evaluation against near-real-time satellite and surface measurements. Using spatially and temporally collocated sampling of the model output along the flight track, and combining the aerosol measurements with those of gas-phase precursors such as sulfur dioxide (SO2) and nitric acid (HNO3) from the chemical ionization mass spectrometer (CIT-CIMS), we show how this technique can be used to provide valuable constraints and validation for the development of more complex aerosol speciation schemes.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A11F2268K
- Keywords:
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- 0322 Constituent sources and sinks;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 1910 Data assimilation;
- integration and fusion;
- INFORMATICSDE: 1986 Statistical methods: Inferential;
- INFORMATICSDE: 3260 Inverse theory;
- MATHEMATICAL GEOPHYSICS