Description and Evaluation of an Emission-Driven and Fully Coupled Methane Cycle in UKESM1
Description and Evaluation of an Emission-Driven and Fully Coupled Methane Cycle in UKESM1
复制标题
UKESM1 中排放驱动且完全耦合的甲烷循环的描述和评估
DOI：
10.1029/2021ms002982
复制
发表时间：
2022
影响因子：
6.8
通讯作者：
Folberth G
中科院分区：
文献类型：
--
作者：
Folberth G
甲烷（CH 4）是大气中最重要的微量气体之一，是一种非常有效的温室气体和大气污染物。因此，更好地了解全球甲烷循环及其与地球系统的相互作用对于未来人为气候变化的预测和多气体减排战略的评估是必要的。在这里，我们提出了一个新开发的甲烷排放驱动的地球系统模型，以完全交互式地模拟全球甲烷循环。我们提供了甲烷源和汇的评估以及全周期甲烷预算及其在历史时期的变化。我们进一步评估甲烷大气丰度和寿命对现有的观测。新的甲烷排放驱动模型在观测不确定性范围内模拟了甲烷循环的所有组成部分。我们计算了目前（2000-2009年十年平均）甲烷的总来源为591 Tg（CH 4）yr− 1，其中197 Tg（CH 4）yr− 1来自湿地。这些来源几乎被全球甲烷汇所平衡，达到580 Tg（CH 4）yr−1;甲烷与对流层中羟基自由基的反应单独消除了525 Tg（CH 4）yr−1。11 Tg（CH 4）yr− 1的源和汇之间的不平衡代表了大气甲烷的增长率，与目前最好的估计值5.8 Tg（CH 4）yr− 1相当吻合，范围为4.9-6.6 Tg（CH 4）yr−1。目前，该模型显示甲烷表面摩尔分数的最大系统负偏差约为200 ppb。
Methane (CH4) is one of the most important trace gases in the atmosphere owing to its role as an exceedingly effective greenhouse gas and atmospheric pollutant. Better understanding of the global methane cycle and its interactions with the Earth system is therefore necessary for robust future projections of anthropogenic climate change and assessments of multi‐gas mitigation strategies. Here we present a newly developed methane emission‐driven Earth system model to simulate the global methane cycle fully interactively. We provide an evaluation of methane sources and sinks and a full‐cycle methane budget and its change over the historic period. We further evaluate the methane atmospheric abundance and lifetime against available observations. The new methane emission‐driven model simulates all the components of the methane cycle within observational uncertainty. We calculate a total present‐day (2000–2009 decadal average) methane source of 591 Tg(CH4) yr−1with 197 Tg(CH4) yr−1coming from wetlands. These sources are nearly balanced by the global methane sinks amounting to 580 Tg (CH4) yr−1; reaction of methane with the hydroxyl radical in the troposphere alone removes 525 Tg(CH4) yr−1. The imbalance between sources and sinks of 11 Tg(CH4) yr−1represents the atmospheric methane growth rate and is in fairly good agreement with current best estimates of 5.8 Tg(CH4) yr−1with a range of 4.9–6.6 Tg(CH4) yr−1. At present‐day the model shows a maximum systematic negative‐bias of approximately 200 ppb in the methane surface mole fraction.