DOI: 10.1002/2017JD026933
论文题名: Saharan dust, convective lofting, aerosol enhancement zones, and potential impacts on ice nucleation in the tropical upper troposphere
作者: Twohy C.H. ; Anderson B.E. ; Ferrare R.A. ; Sauter K.E. ; L'Ecuyer T.S. ; van den Heever S.C. ; Heymsfield A.J. ; Ismail S. ; Diskin G.S.
刊名: Journal of Geophysical Research: Atmospheres
ISSN: 2169897X
出版年: 2017
卷: 122, 期: 16 起始页码: 8833
结束页码: 8851
语种: 英语
英文关键词: aerosol particles
; convective clouds
; ice nuclei
; indirect effect
; mineral dust
; tropical convection
英文摘要: Dry aerosol size distributions and scattering coefficients were measured on 10 flights in 32 clear-air regions adjacent to tropical storm anvils over the eastern Atlantic Ocean. Aerosol properties in these regions were compared with those from background air in the upper troposphere at least 40 km from clouds. Median values for aerosol scattering coefficient and particle number concentration >0.3 μm diameter were higher at the anvil edges than in background air, showing that convective clouds loft particles from the lower troposphere to the upper troposphere. These differences are statistically significant. The aerosol enhancement zones extended ~10–15 km horizontally and ~0.25 km vertically below anvil cloud edges but were not due to hygroscopic growth since particles were measured under dry conditions. Number concentrations of particles >0.3 μm diameter were enhanced more for the cases where Saharan dust layers were identified below the clouds with airborne lidar. Median number concentrations in this size range increased from ~100 l−1 in background air to ~400 l−1 adjacent to cloud edges with dust below, with larger enhancements for stronger storm systems. Integration with satellite cloud frequency data indicates that this transfer of large particles from low to high altitudes by convection has little impact on dust concentrations within the Saharan Air Layer itself. However, it can lead to substantial enhancement in large dust particles and, therefore, heterogeneous ice nuclei in the upper troposphere over the Atlantic. This may induce a cloud/aerosol feedback effect that could impact cloud properties in the region and downwind. ©2017. American Geophysical Union. All Rights Reserved. 资助项目: NNX06AC65G
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/62610
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: NorthWest Research Associates, Redmond, WA, United States; NASA Langley Research Center, Hampton, VA, United States; Department of Atmospheric and Oceanic Sciences, University of Wisconsin, Madison, WI, United States; Department of Atmospheric Science, Colorado State University, Fort Collins, CO, United States; Microscale and Mesoscale Meteorology Laboratory, National Center for Atmospheric Research, Boulder, CO, United States
Recommended Citation:
Twohy C.H.,Anderson B.E.,Ferrare R.A.,et al. Saharan dust, convective lofting, aerosol enhancement zones, and potential impacts on ice nucleation in the tropical upper troposphere[J]. Journal of Geophysical Research: Atmospheres,2017-01-01,122(16)