To: Broken_Clock who wrote (1261281 ) 9/11/2020 3:13:13 PM From: Wharf Rat Respond to of 1575858
Dr Thomas Smith ???? Jul 21st 2020 , 10 tweets, 8 min read Bookmark Save as PDF My Authors New spatial analysis of wildfires across the Arctic in May/June 2020, and how they compare to the satellite record (2003-2020). What is burning? Are there peat fires? What about permafrost? ?????thread in collab with @m_parrington @CopernicusECMWF #ArcticFires [1/9] The Arctic Circle is an ecologically arbitrary line, so I also investigated fires burning north of the treeline, using @NSIDC 's tundra & boreal forest boundary, a better representation of the Arctic Zone. May/June 2020 saw 10x more fires than 2003-18 average for this zone. [2/9] Using a Global Landcover dataset, we see corroborating evidence that the spike in fire activity in 2019/20 occurred in both the boreal forest (tree cover) and tundra (herbaceous & shrub cover) ecosystems of the Arctic Circle [3/9] Peat soils are widespread in Arctic & Boreal biomes. We can use a global peatland map to determine proportion of the fires burning on mapped areas known to contain peat. Around half of the fires are on peat soils, with a big increase in total fires on peat in 2019 & 2020 [4/9] Some of these fires will have ignited underlying peat soils, although the area affected is difficult to determine from satellites. High-res imagery from @Sentinel_hub shows substantial areas of residual smouldering & fire spots burning long after the main fire has passed [5/9] A map of permafrost from @NSIDC can be used to delineate whether fires are burning on continuous vs discontinuous permafrost, & the ice loading of those areas. Almost all of the fires in 2019 & 2020 were on continuous permafrost with high ice loading [6/9] Finally, if we look at the latitudinal distribution of all May/June fires north of 60-degrees. We can see a very unusual distribution in 2019 & 2020, a noticeable shift to the north. Watch the animation in the next tweet... [7/9] Here's an animation of high latitude May/June fires accumulating from 2003 to 2020, watch the Arctic fires emerging in 2019 and 2020 at the end of the animation. [8/9] Data sources: ?? @NASAEarth Fire hotspots processed by @M_parrington @CopernicusECMWF ???Global Landcover @EU_ScienceHub : forobs.jrc.ec.europa.eu/products/glc20… ??Treeline and Permafrost @NSIDC : nsidc.org/data/ggd318 ??Global peat map (Yu et al., 2010: researchgate.net/publication/23… ) [9/9] High resolution version of this animation can be found here: May/June high latitude wildfires latitudinal distribution animationHere's an animation of high latitude May/June fires accumulating from 2003 to 2020, watch the Arctic fires emerging in 2019 and 2020 at the end of the animation. Click to see full-size version: …http://drtels.co.uk/drtels/blog/may-june-high-latitude-wildfires-latitudinal-distribution-animation/ Missing some Tweet in this thread? You can try to force a refresh . Tweet Share Email Embed threadreaderapp.com