首页> 外文期刊>Global change biology >Polygonal tundra geomorphological change in response to warming alters future CO2 and CH4 flux on the Barrow Peninsula
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Polygonal tundra geomorphological change in response to warming alters future CO2 and CH4 flux on the Barrow Peninsula

机译:响应变暖的多边形冻原地貌变化改变了巴罗半岛未来的CO2和CH4通量

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摘要

The landscape of the Barrow Peninsula in northern Alaska is thought to have formed over centuries to millennia, and is now dominated by ice-wedge polygonal tundra that spans drained thaw-lake basins and interstitial tundra. In nearby tundra regions, studies have identified a rapid increase in thermokarst formation (i.e., pits) over recent decades in response to climate warming, facilitating changes in polygonal tundra geomorphology. We assessed the future impact of 100years of tundra geomorphic change on peak growing season carbon exchange in response to: (i) landscape succession associated with the thaw-lake cycle; and (ii) low, moderate, and extreme scenarios of thermokarst pit formation (10%, 30%, and 50%) reported for Alaskan arctic tundra sites. We developed a 30x30m resolution tundra geomorphology map (overall accuracy:75%; Kappa:0.69) for our similar to 1800km(2) study area composed of ten classes; drained slope, high center polygon, flat-center polygon, low center polygon, coalescent low center polygon, polygon trough, meadow, ponds, rivers, and lakes, to determine their spatial distribution across the Barrow Peninsula. Land-atmosphere CO2 and CH4 flux data were collected for the summers of 2006-2010 at eighty-two sites near Barrow, across the mapped classes. The developed geomorphic map was used for the regional assessment of carbon flux. Results indicate (i) at present during peak growing season on the Barrow Peninsula, CO2 uptake occurs at -902.3 10(6)gC-CO(2)day(-1) (uncertainty using 95% CI is between -438.3 and -1366 10(6)gC-CO(2)day(-1)) and CH4 flux at 28.9 10(6)gC-CH(4)day(-1)(uncertainty using 95% CI is between 12.9 and 44.9 10(6)gC-CH(4)day(-1)), (ii) one century of future landscape change associated with the thaw-lake cycle only slightly alter CO2 and CH4 exchange, while (iii) moderate increases in thermokarst pits would strengthen both CO2 uptake (-166.9 10(6)gC-CO(2)day(-1)) and CH4 flux (2.8 10(6)gC-CH(4)day(-1)) with geomorphic change from low to high center polygons, cumulatively resulting in an estimated negative feedback to warming during peak growing season.
机译:人们认为,阿拉斯加北部巴罗半岛的景观已形成了数百年至数千年,如今已由横跨排水的融化湖盆地和间质苔原的冰楔形多边形苔原所主导。在附近的苔原地区,研究发现近几十年来,随着气候变暖,热喀斯特地貌(即矿坑)迅速增加,促进了多边形苔原地貌的变化。为了评估以下因素,我们评估了苔原地貌变化100年对峰生季节碳交换的未来影响: (ii)据报阿拉斯加北极寒带苔原站点的热喀斯特坑形成的低,中和极端情况(10%,30%和50%)。我们针对类似于十个级别的1800 km(2)研究区域,开发了分辨率为30x30m的苔原地貌图(总体精度:75%; Kappa:0.69);排水坡,高中心多边形,平中心多边形,低中心多边形,聚结低中心多边形,多边形槽,草甸,池塘,河流和湖泊,以确定它们在巴罗半岛的空间分布。跨地图类别,在巴罗附近的八十二个地点收集了2006-2010年夏季的陆地大气CO2和CH4通量数据。所开发的地貌图用于碳通量的区域评估。结果表明(i)目前在巴罗半岛(Barrow Peninsula)高峰期,CO2吸收发生在-902.3 10(6)gC-CO(2)day(-1)(使用95%CI的不确定性在-438.3和-1366之间10(6)gC-CO(2)day(-1))和CH4流量为28.9 10(6)gC-CH(4)day(-1)(使用95%CI的不确定度在12.9和44.9之间10(6 )gC-CH(4)day(-1)),(ii)与融化湖周期相关的未来一个世纪的景观变化只会稍微改变CO2和CH4的交换,而(iii)温热岩溶坑的适度增加会增强两者CO2吸收(-166.9 10(6)gC-CO(2)day(-1))和CH4通量(2.8 10(6)gC-CH(4)day(-1))从低中心到高中心的地貌变化多边形,在高峰生长季节累计导致对变暖的估计负反馈。

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