文章基本信息

标题：Large CO2 effluxes at night and during synoptic weather events significantly contribute to CO2 emissions from a reservoir
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作者：Heping Liu ; Qianyu Zhang ; Gabriel G Katul 等
期刊名称：Environmental Research Letters
印刷版ISSN：1748-9326
电子版ISSN：1748-9326
出版年度：2016
卷号：11
期号：6
页码：064001
DOI：10.1088/1748-9326/11/6/064001
语种：English
出版社：IOP Publishing Ltd
摘要：CO₂ emissions from inland waters are commonly determined by indirect methods that are based on the product of a gas transfer coefficient and the concentration gradient at the air water interface (e.g., wind-based gas transfer models). The measurements of concentration gradient are typically collected during the day in fair weather throughout the course of a year. Direct measurements of eddy covariance CO₂ fluxes from a large inland water body (Ross Barnett reservoir, Mississippi, USA) show that CO₂ effluxes at night are approximately 70% greater than those during the day. At longer time scales, frequent synoptic weather events associated with extratropical cyclones induce CO₂ flux pulses, resulting in further increase in annual CO₂ effluxes by 16%. Therefore, CO₂ emission rates from this reservoir, if these diel and synoptic processes are under-sampled, are likely to be underestimated by approximately 40%. Our results also indicate that the CO₂ emission rates from global inland waters reported in the literature, when based on indirect methods, are likely underestimated. Field samplings and indirect modeling frameworks that estimate CO₂ emissions should account for both daytime–nighttime efflux difference and enhanced emissions during synoptic weather events. The analysis here can guide carbon emission sampling to improve regional carbon estimates.