Aerosol responses to precipitation along North American air trajectories arriving at Bermuda

• Published in: Atmospheric Chemistry and Physics
• Main Authors: H. Dadashazar, M. Alipanah, M. R. A. Hilario, E. Crosbie, S. Kirschler, H. Liu, R. H. Moore, A. J. Peters, A. J. Scarino, M. Shook, K. L. Thornhill, C. Voigt, H. Wang, E. Winstead, B. Zhang, L. Ziemba, A. Sorooshian
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2021
• Subjects: Physics; QC1-999; Chemistry; QD1-999; North Atlantic
• Online Access: https://doi.org/10.5194/acp-21-16121-2021; https://doaj.org/article/a60d2bd817764bd0b1e3b69c9b680471

North American pollution outflow is ubiquitous over the western North Atlantic Ocean, especially in winter, making this location a suitable natural laboratory for investigating the impact of precipitation on aerosol particles along air mass trajectories. We take advantage of observational data collected at Bermuda to seasonally assess the sensitivity of aerosol mass concentrations and volume size distributions to accumulated precipitation along trajectories (APT). The mass concentration of particulate matter with aerodynamic diameter less than 2.5 µm normalized by the enhancement of carbon monoxide above background (PM <math xmlns="http://www.w3.org/1998/Math/MathML" id="M2" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi/><mn mathvariant="normal">2.5</mn></msub><mo>/</mo><mi mathvariant="normal">Δ</mi></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="28pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="5ae6b0495bee251fbac1bfef6bb6209c"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="acp-21-16121-2021-ie00001.svg" width="28pt" height="14pt" src="acp-21-16121-2021-ie00001.png"/></svg:svg> CO) at Bermuda was used to estimate the degree of aerosol loss during transport to Bermuda. Results for December–February (DJF) show that most trajectories come from North America and have the highest APTs, resulting in a significant reduction (by 53 %) in PM <math xmlns="http://www.w3.org/1998/Math/MathML" id="M3" display="inline" overflow="scroll" dspmath="mathml"><mrow><msub><mi/><mn mathvariant="normal">2.5</mn></msub><mo>/</mo><mi mathvariant="normal">Δ</mi></mrow></math> <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="28pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="c8fdc99ec2b4407938f2aa5aba123896"><svg:image ...