Global terrestrial isoprene emission models: sensitivity to variability in climate and vegetation
Global terrestrial isoprene emission models: sensitivity to variability in climate and vegetation
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DOI：
10.5194/acp-11-8037-2011
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发表时间：
2011-01-01
影响因子：
6.3
通讯作者：
Guenther, A.
中科院分区：
文献类型：
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作者：
Arneth, A.;Schurgers, G.;Guenther, A.
由于异戊二烯对甲烷的大气寿命、对流层臭氧负担和二次有机气溶胶增长的影响，异戊二烯是评估人为空气污染-气候变化相互作用时需要考虑的生物源化合物之一。由于缺乏对叶异戊二烯生产过程的了解，也缺乏适当的观测来限制和评价区域或全球模拟结果，因此对过去、现在和未来的排放量估计增加了很大的不确定性。着眼于当代气候条件下，我们比较了三个全球异戊二烯模型，不同的植被和异戊二烯排放算法的代表。我们的具体目标是研究模型之间和模型内的变化，这是通过改变一些模型的主要特征，并确定哪些空间和/或时间特征是强大的模型和不同的实验设置。在各自的标准配置中，模型在主要异戊二烯来源和排放季节性方面基本一致，最大月排放率约为20-25 Tg C，按30度纬度带平均。它们还表明全球总排放量的年际变化相对较小（约为平均值的5%至10%）。这些模型对一个或多个主要模型组件和驱动因素的变化敏感。例如，在一个实施例中，（b）气候输入（包括底层植被、气候输入）可导致年排放总量累计增加或减少30%以上。不同的驱动因素也会强烈改变季节性排放模式。需要根据植被的排放能力以及光、辐射和温度的绝对和区域分布的差异来解释可变的响应，但模拟排放变化的方向并不像预期的那样一致。我们的研究结果强调了建模者在使用非标准排放模型配置进行模拟时，需要仔细评估异戊二烯排放模型的实施情况。
Due to its effects on the atmospheric lifetime of methane, the burdens of tropospheric ozone and growth of secondary organic aerosol, isoprene is central among the biogenic compounds that need to be taken into account for assessment of anthropogenic air pollution-climate change interactions. Lack of process-understanding regarding leaf isoprene production as well as of suitable observations to constrain and evaluate regional or global simulation results add large uncertainties to past, present and future emissions estimates. Focusing on contemporary climate conditions, we compare three global isoprene models that differ in their representation of vegetation and isoprene emission algorithm. We specifically aim to investigate the between-and within model variation that is introduced by varying some of the models' main features, and to determine which spatial and/or temporal features are robust between models and different experimental set-ups. In their individual standard configurations, the models broadly agree with respect to the chief isoprene sources and emission seasonality, with maximum monthly emission rates around 20-25 Tg C, when averaged by 30-degree latitudinal bands. They also indicate relatively small (approximately 5 to 10% around the mean) interannual variability of total global emissions. The models are sensitive to changes in one or more of their main model components and drivers (e. g., underlying vegetation fields, climate input) which can yield increases or decreases in total annual emissions of cumulatively by more than 30 %. Varying drivers also strongly alters the seasonal emission pattern. The variable response needs to be interpreted in view of the vegetation emission capacities, as well as diverging absolute and regional distribution of light, radiation and temperature, but the direction of the simulated emission changes was not as uniform as anticipated. Our results highlight the need for modellers to evaluate their implementations of isoprene emission models carefully when performing simulations that use nonstandard emission model configurations.