Sunday, 7 January 2018
Exhibit Hall 5 (ACC) (Austin, Texas)
The Atmospheric Carbon Transport – America (ACT-America) project aims to enhance our understanding of greenhouse gas (GHG) fluxes and transport on regional and continental scales with a key aim to investigate the impact of synoptic scale weather systems on GHGs. Within this work, we investigate the spatial variability of daytime atmospheric boundary layer (ABL) depths on synoptic scale to explore the impact of frontal systems on ABL depths using backscatter lidar observations onboard NASA's C-130 aircraft during the in ACT-America summer 2016 campaign. Among the three campaign study regions (mid-Atlantic, mid-west, south) a total of 25 fair weather, frontal, and OCO-2/hybrid flights were conducted. Aerosol layer heights were retrieved from lidar backscatter profiles by applying the Haar wavelet transformation. To attribute ABL top heights among three potential aerosol layers, an attribution filter was developed to help eliminate outliers (e.g. extreme vertical shifts from aerosol layers and clouds) and finally determine most reliable ABL top heights. A detailed intercomparison study indicates that the wavelet-based approach performed better than the traditional gradient-based approach for deriving the ABL top heights, based on a correlation analysis of 106 samples of ABL heights derived using thermodynamic profiles along the C-130 flight track. Lidar observations during stormy weather conditions (11 cases) show that the ABL gradually deepens in the cold sector with increasing distance from the frontal boundary. Future research will explore the processes governing ABL depth changes across frontal boundaries as well as how ABL depth variability in synoptic weather systems impact GHG concentrations.
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