DOI: 10.1016/j.atmosenv.2014.05.062
Scopus记录号: 2-s2.0-84902261500
论文题名: Widespread reductions in haze across the United States from the early 1990s through 2011
作者: Hand J ; L ; , Schichtel B ; A ; , Malm W ; C ; , Copeland S ; , Molenar J ; V ; , Frank N ; , Pitchford M
刊名: Atmospheric Environment
ISSN: 0168-2563
EISSN: 1573-515X
出版年: 2014
卷: 94 起始页码: 671
结束页码: 679
语种: 英语
英文关键词: Aerosol trends
; Haze
; Remote aerosols
; Visibility
Scopus关键词: Aerosols
; Sulfur dioxide
; Ambient light
; Haze
; Interagency monitoring of protected visual environments
; National parks
; Regional Haze Rule
; Sulfate concentrations
; Sulfur dioxide emissions
; Visibility degradation
; Visibility
; sulfate
; sulfur dioxide
; climate modeling
; climate variation
; concentration (composition)
; estimation method
; haze
; light availability
; particulate matter
; simulation
; aerosol
; article
; concentration (parameters)
; degradation
; geography
; haze
; light
; national park
; particulate matter
; priority journal
; simulation
; trend study
; United States
; visibility
; United States
Scopus学科分类: Environmental Science: Water Science and Technology
; Earth and Planetary Sciences: Earth-Surface Processes
; Environmental Science: Environmental Chemistry
英文摘要: Visibility has improved significantly at many remote areas across the United States since the early 1990s. Trends in visibility were calculated using ambient light extinction coefficients (bext) estimated from speciated particulate concentrations measured by the IMPROVE (Interagency Monitoring of Protected Visual Environments) network. The 20% haziest bext levels were computed for each year following Regional Haze Rule guidelines and aggregated over three major regions of the United States. Over the last two decades (1992-2011) the regional mean 20% haziest bext dropped by 52% (-2.6%yr-1, p<0.01) in the eastern United States, and by 20% (-1.0%yr-1, p=0.08) for sites along the West Coast. However, in the Intermountain/Southwest region, the trend was insignificant (-0.2%yr-1, p=0.36). Over the last decade (2002-2011) the haziest bext in the Intermountain/Southwest region decreased by 15% (-1.5%yr-1, p=0.09), compared to a decrease of 35% (-3.5%yr-1, p=0.06) in the West Coast region and 50% (-5.0%yr-1, p=0.02) in the East. A novel aspect to this study is the visualization of trends through the simulation of images of national parks and other remote areas for early and current haziest conditions. These images are an effective means for communicating trends and illustrate the dramatic improvement in visibility, especially in the East, where reductions in sulfate concentrations and sulfur dioxide emissions have had a positive impact on visibility degradation. However, while conditions are clearer for regions in the West, less improvement points to the need for understanding the influences on the trends in haziest conditions in those regions. © 2014 Elsevier Ltd. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/81232
Appears in Collections: 气候变化事实与影响
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作者单位: Cooperative Institute for Research in the Atmosphere, Colorado State University, Fort Collins, CO 80523, United States; National Park Service, Cooperative Institute for Research in the Atmosphere, Colorado State University, Fort Collins, CO 80523, United States; Air Resource Specialists, 1901 Sharp Point Drive, Suite E, Fort Collins, CO 80525, United States; Air Quality Assessment Division, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711, United States; Division of Atmospheric Sciences, Desert Research Institute, Reno, NV 89512, United States
Recommended Citation:
Hand J,L,, Schichtel B,et al. Widespread reductions in haze across the United States from the early 1990s through 2011[J]. Atmospheric Environment,2014-01-01,94