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Physicochemical Properties of Vertically Resolved Aerosols Collected over the Arctic via Tethered Balloon System
NURUN NAHAR LATA, Darielle Dexheimer, Fan Mei, Zezhen Cheng, Rhenton Brimberry, Swarup China, Michigan Technological University
Abstract Number: 561
Working Group: Aerosols, Clouds and Climate
Abstract
The Physicochemical properties of aerosols play a vital role in affecting the Arctic climate via both aerosol-radiation and aerosol-cloud interactions. Though several ground-based observations demonstrate the seasonal variation of Arctic aerosol climatic impacts, the current understanding of the aerosol-cloud interaction in vertically stratified Arctic atmosphere is still limited. Thus, we aim to understand the physicochemical properties, sources, and atmospheric processing of aerosol at different altitudes by investigating ground-based in-situ and remote sensing data, backward trajectory analysis, and off-line size-resolved chemical composition analysis. The vertical profile of the aerosols was studied with the tethered balloon system (TBS), which was deployed at the U.S. Department of Energy Atmospheric Radiation Measurement Program’s mobile facility (AMF3) at Oliktok Point, Alaska, on the Arctic Ocean coast. The aerosol sampling was performed at different altitudes, ranging up to 1100 m employing a cascade impactor during August 2019. We perform single-particle analysis using chemical imaging and multi-modal micro-spectroscopy techniques such as computer-controlled scanning electron microscopy with energy-dispersive X-ray spectroscopy (CCSEM/EDX), transmission electron microscopy (TEM) and scanning transmission X-ray microscopy with near-edge X-ray absorption fine structure spectroscopy (STXM/NEXAFS). Aerosol chemical compositions observed by TBS showed a clear temporal and spatial variation. Wider size distribution of the particles at high-altitude was observed compared with that of low-altitude particles on the same sampling day. A relatively higher percent of sulfate and sulfate coated dust aerosols were observed at higher altitudes, suggesting the possibility of cloud processing of aerosols. Altogether, the findings from this study will improve the understanding of the implication of Arctic aerosol on Arctic cloud formation and radiative properties.