Modeling the Effect of Moss Cover on Soil Temperature and Carbon Fluxes at a Tundra Site in Northeastern Siberia
Modeling the Effect of Moss Cover on Soil Temperature and Carbon Fluxes at a Tundra Site in Northeastern Siberia
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模拟西伯利亚东北部苔原地区苔藓覆盖对土壤温度和碳通量的影响
DOI：
10.1029/2018jg004491
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发表时间：
2018
期刊：
影响因子：
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通讯作者：
Fedorov Alexander N.
中科院分区：
文献类型：
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作者：
Park Hotaek;Launiainen Samuli;Konstantinov Pavel Y.;Iijima Yoshihiro;Fedorov Alexander N.
苔藓对水和热通量的影响很大，因为它们具有很高的持水能力和绝缘性。利用陆面模型(水文-生物地球化学耦合过程模型，CHANGE)定量评价了苔藓覆盖对土壤温度(TSOIL)、活动层厚度(ALT)和生态系统碳平衡的影响。变化模型与苔藓过程模块相结合，能够显式地表示大气-植被-苔藓-土壤系统中的热量、水和碳交换。该模型在1980-2013年间应用于西伯利亚东北部的冻土带遗址。结果得到了现场观测的验证，表明苔藓具有很高的绝缘水平，导致冬季较温暖，夏季较凉爽，ALT较小。通过模型试验考察了TSOIL和ALT对苔藓盖度和厚度的敏感性。与没有苔藓的实验相比，苔藓厚度的增加使夏季TSOIL降低了0.9-2.1℃，ALT降低了9-20℃。苔藓诱导的根区冷害会因冰的存在而减少植物根部的水分供应，从而限制植被的生产力。这一限制随着苔藓层厚度和盖度的增加而增加。苔藓本身的生产力随着厚度的增加而增加，部分抵消了植被生产力的下降。我们的模拟研究表明，苔藓层对北极冻土带的TSOIL、ALT和碳平衡有重要影响，并可能在未来北极变暖中发挥重要作用。
Mosses strongly affect water and heat fluxes due their high water holding capacity and the provision of insulation. A land surface model (the coupled hydrological and biogeochemical process model, CHANGE) was used to quantitatively assess the influence of moss cover on soil temperature (TSOIL), active layer thickness (ALT), and ecosystem carbon balance. The CHANGE model was coupled with a moss process module, enabling the explicit representation of heat, water, and carbon exchange in the atmosphere‐vegetation‐moss‐soil system. The model was applied to a tundra site in northeastern Siberia over the period of 1980–2013. The results were validated with in situ observations and indicated a high level of insulation by the moss, resulting in warmer winter and cooler summerTSOILand smaller ALT. The sensitivities ofTSOILand ALT to moss coverage and thickness were examined using model experiments. An increase in moss thickness lowered the summerTSOILby 0.9–2.1 °C and reduced ALT by 9–20 cm compared with a moss‐free experiment. The moss‐induced coolerTSOILin the root zone could limit the productivity of vegetation by reducing water availability to plant roots due to the presence of ice. This limitation increased with increasing moss layer thickness and coverage. The productivity of the moss itself increased with thickness, partially offsetting the reduction in vegetation productivity. Our modeling study suggests that the moss layer has a significant impact onTSOIL, ALT, and carbon balance in the Arctic tundra and may play an important role in future Arctic warming.