Creating a Unified Airborne Database for Assessment and Validation of Global Models of Atmospheric Composition

In response to NASA’s MEaSUREs announcement, we propose to provide Earth System Data records critical to the validation and assessment of global models. While these records are expected to be of use to the modeling community at large, they are, for example, already of interest to a broad group of global chemistry and climate modeling groups participating in recent Atmospheric Chemistry and Climate (AC&C) initiatives endorsed by the WCRP-SPARC/IGBP-IGAC, which aim to address uncertainties in atmospheric chemistry-climate interactions. The proposed 4-year effort has been broadly endorsed by modeling groups which are engaging in assessment and validation activities, primarily including AC&C, AeroCom, and HTAP. The proposed activities will directly address the critical needs related to the top two activities recently selected by AC&C, i.e., 1) a 20-25 year hindcast of tropospheric ozone and aerosols, and 2) a definition of processes that control the distribution of the tropospheric trace gases/aerosols between mid and upper troposphere.  The proposed effort will enable model verification and comparison exercises associated with these activities by providing observational data in appropriate format and temporal and spatial scales along with objectively assessed uncertainties.  We proposed to create airborne ESDR (Earth System Data Record) products which will be derived from a wealth of publicly available airborne data sets accumulated primarily from NASA airborne field studies as well as from studies sponsored by NOAA, NSF and international partners over the past two decades.  The proposed project will be focused in 3 areas:

1. To compile publicly available data sets from NASA airborne campaigns as well as from the other campaigns sponsored by NOAA, NSF and international partners.
2. To assemble a measurement evaluation panel, including both measurement experts and modelers from a broad spectrum of institutions and agencies, to provide objective assessment of measurement uncertainties and biases and to determine how to best integrate these observations into forms useful for model comparison.
3.  To generate a standardized in-situ observational database with best possible matching temporal and spatial scales to model output, which represents snap-shot spatial distributions of trace gas species and aerosol properties of interest.

Previous studies have shown the importance of model comparisons to revealing inadequate understanding or representation of critical processes.  However, AC&C recently identified several barriers to useful comparisons of models and observations, including a general lack of understanding between the modeling and measurement communities, a lack of a centralized and standardized observational database, insufficient information on data quality and uncertainties, and difficulties posed by mismatches in the temporal and spatial scales of model output and measurements.  The proposed activities will make efforts to bridge the gaps between the modeling and measurement communities, address the measurement uncertainty issues, and provide standardized data with best possible matching with model temporal and spatial scales.  We believe that our airborne ESDR products will be useful to AC&C recommended modeling activities as well as the satellite community in terms of validation and potential retrieval algorithm improvement.  In summary, the results of the proposed project will be an important part of the effort to maximize the value of the NASA suborbital program and to make a significant contribution to improve the current understanding of atmospheric chemistry and its interactions with climate as well as the ability to predict climate change.

Gao Chen - PI, LARC