Purpose of Review

While previously thought to be negligible, carbon emissions during the non-growing season (NGS) can be a substantial part of the annual carbon budget in the Arctic boreal zone (ABZ), which can shift the carbon balance of these ecosystems from a long-held annual carbon sink towards a net annual carbon source. The purpose of this review is to summarize NGS carbon dioxide (CO₂) flux research in the ABZ that has been published within the past 5 years.

Recent Findings

We explore the processes and magnitudes of CO₂ fluxes, and the status of modeling efforts, and evaluate future directions. With technological advances, direct measurements of NGS fluxes are increasing at sites across the ABZ over the past decade, showing ecosystems in the ABZ are a large source of CO₂ in the shoulder seasons, with low, consistent, winter emissions.

Summary

Ecosystem carbon cycling models are being improved with some challenges, such as modeling below ground and snow processes, which are critical to understanding NGS CO₂ fluxes. A lack of representative in situ carbon flux data and gridded environmental data are leading limiting factors preventing more accurate predictions of NGS carbon fluxes.

中文翻译：

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北极寒带地区非生长季节二氧化碳通量监测和建模的最新进展和挑战

审查目的

虽然以前被认为可以忽略不计，但非生长季节 (NGS) 期间的碳排放可能是北极寒带地区 (ABZ) 年度碳预算的很大一部分，这可能会改变这些生态系统的碳平衡。将年度碳汇保持为年度净碳源。本综述的目的是总结过去 5 年内发表的 ABZ 中NGS 二氧化碳 (CO _{2 ) 通量研究。}

最近的发现

_{我们探索 CO 2}通量的过程和大小以及建模工作的状态，并评估未来的方向。随着技术的进步，过去十年来，ABZ 各地点对 NGS 通量的直接测量不断增加，这表明 ABZ 的生态系统是平季CO _{2的重要来源，且冬季排放量较低且持续。}

概括

生态系统碳循环模型正在不断改进，但面临一些挑战，例如地下和雪过程建模，这对于理解 NGS CO ₂通量至关重要。缺乏代表性的原位碳通量数据和网格环境数据是阻碍 NGS 碳通量更准确预测的主要限制因素。