Increasing contribution of peatlands to boreal evapotranspiration in a warming climate
Increasing contribution of peatlands to boreal evapotranspiration in a warming climate
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DOI：
10.1038/s41558-020-0763-7
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发表时间：
2020-05-11
影响因子：
30.7
通讯作者：
Zyrianov, Vyacheslav
中科院分区：
文献类型：
--
作者：
Helbig, Manuel;Waddington, James Michael;Zyrianov, Vyacheslav
气候变暖增加了北部泥炭地的蒸散(ET)，而不是森林。观察表明，泥炭地的ET比森林的ET高出30%，这表明泥炭地对气候变暖的反应更强烈。地球系统模型没有完全考虑泥炭地，因此可能低估了未来的北部地区ET值。蒸发蒸腾(ET)对气候变暖的响应对北部生物群的水和碳循环至关重要，北部生物群是以森林和泥炭地为主的土地覆盖类型的镶嵌。由于泥炭地在地球系统模型中没有明确地表示为植物功能类型，因此气候变暖导致的蒸气压亏差(VPD)增加对北方ET的影响仍然知之甚少。这里，我们利用95个涡旋协方差塔场的观测数据表明，泥炭地的蒸散量随VPD的增加比森林的蒸散量增加得多。当VPD大于2kPa时，泥炭地的蒸腾速率比森林的蒸腾速率高30%。未来(2091-2100年)生长中期泥炭地的蒸散量估计将超过森林蒸散量的20%以上，RCP4.5约三分之一的北方生物群和RCP8.5约三分之二的生物群。因此，泥炭地特定的ET对VPD的响应应包括在地球系统模型中，以避免水和碳循环预测中的偏差。
Climate warming increases evapotranspiration (ET) more in boreal peatlands than in forests. Observations show that peatland ET can exceed forest ET by up to 30%, indicating a stronger warming response in peatlands. Earth system models do not fully account for peatlands and hence may underestimate future boreal ET.The response of evapotranspiration (ET) to warming is of critical importance to the water and carbon cycle of the boreal biome, a mosaic of land cover types dominated by forests and peatlands. The effect of warming-induced vapour pressure deficit (VPD) increases on boreal ET remains poorly understood because peatlands are not specifically represented as plant functional types in Earth system models. Here we show that peatland ET increases more than forest ET with increasing VPD using observations from 95 eddy covariance tower sites. At high VPD of more than 2 kPa, peatland ET exceeds forest ET by up to 30%. Future (2091-2100) mid-growing season peatland ET is estimated to exceed forest ET by over 20% in about one-third of the boreal biome for RCP4.5 and about two-thirds for RCP8.5. Peatland-specific ET responses to VPD should therefore be included in Earth system models to avoid biases in water and carbon cycle projections.