DOI: 10.5194/tc-14-3731-2020
论文题名: Tracing devastating fires in Portugal to a snow archive in the Swiss Alps: A case study
作者: Osmont D. ; Brugger S. ; Gilgen A. ; Weber H. ; Sigl M. ; Modini R.L. ; Schwörer C. ; Tinner W. ; Wunderle S. ; Schwikowski M.
刊名: Cryosphere
ISSN: 19940416
出版年: 2021
卷: 14, 期: 11 起始页码: 3731
结束页码: 3745
语种: 英语
英文关键词: aerosol
; black carbon
; charcoal
; land use change
; MODIS
; precipitation (climatology)
; remote sensing
; simulation
; snow
; snowpack
; spatiotemporal analysis
; Alps
; Bern [Switzerland]
; Jungfraujoch
; Portugal
; Switzerland
英文摘要: Recent large wildfires, such as those in Portugal in 2017, have devastating impacts on societies, economy, ecosystems and environments. However, wildfires are a natural phenomenon, which has been exacerbated by land use during the past millennia. Ice cores are one of the archives preserving information on fire occurrences over these timescales. A difficulty is that emission sensitivity of ice cores is often unknown, which constitutes a source of uncertainty in the interpretation of such archives. Information from specific and well-documented case studies is therefore useful to better understand the spatial representation of ice-core burning records. The wildfires near Pedrógão Grande in central Portugal in 2017 provided a test bed to link a fire event to its footprint left in a high-alpine snowpack considered a surrogate for high-alpine ice-core sites. Here, we (1) analysed black carbon (BC) and microscopic charcoal particles deposited in the snowpack close to the high-alpine research station Jungfraujoch in the Swiss Alps; (2) calculated backward trajectories based on ERA-Interim reanalysis data and simulated the transport of these carbonaceous particles using a global aerosol-climate model; and (3) analysed the fire spread, its spatial and temporal extent, and its intensity with remote-sensing (e.g. MODIS) Active Fire and Burned Area products. According to modelled emissions of the FINN v1.6 database, the fire emitted a total amount of 203.5 t BC from a total burned area of 501 km2 as observed on the basis of satellite fire products. Backward trajectories unambiguously linked a peak of atmospheric-equivalent BC observed at the Jungfraujoch research station on 22 June - with elevated levels until 25 June - with the highly intensive fires in Portugal. The atmospheric signal is in correspondence with an outstanding peak in microscopic charcoal observed in the snow layer, depositing nearly as many charcoal particles as during an average year in other ice archives. In contrast to charcoal, the amount of atmospheric BC deposited during the fire episode was minor due to a lack of precipitation. Simulations with a global aerosol-climate model suggest that the observed microscopic charcoal particles originated from the fires in Portugal and that their contribution to the BC signal in snow was negligible. Our study revealed that microscopic charcoal can be transported over long distances (1500 km) and that snow and ice archives are much more sensitive to distant events than sedimentary archives, for which the signal is dominated by local fires. The findings are important for future ice-core studies as they document that, for BC as a fire tracer, the signal preservation depends on precipitation. Single events, like this example, might not be preserved due to unfavourable meteorological conditions. © Author(s) 2020. This work is distributed under Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/164777
Appears in Collections: 气候变化与战略
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作者单位: Laboratory of Environmental Chemistry, Paul Scherrer Institut, Villigen, 5232, Switzerland; Department of Chemistry and Biochemistry, University of Bern, Bern, 3012, Switzerland; Oeschger Centre for Climate Change Research, University of Bern, Bern, 3012, Switzerland; Institute of Plant Sciences, University of Bern, Bern, 3012, Switzerland; Institute for Atmospheric and Climate Science, ETH Zürich, Zürich, 8092, Switzerland; Institute of Geography, University of Bern, Bern, 3012, Switzerland; Laboratory of Atmospheric Chemistry, Paul Scherrer Institut, Villigen, 5232, Switzerland; Institut des Géosciences de l'Environnement, Université Grenoble-Alpes, Saint Martin d'Hères, 38400, France
Recommended Citation:
Osmont D.,Brugger S.,Gilgen A.,et al. Tracing devastating fires in Portugal to a snow archive in the Swiss Alps: A case study[J]. Cryosphere,2021-01-01,14(11)