Radiative effects of interannually varying vs. interannually invariant aerosol emissions from fires
Radiative effects of interannually varying vs. interannually invariant aerosol emissions from fires
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DOI：
10.5194/acp-16-14495-2016
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发表时间：
2016-11
影响因子：
6.3
通讯作者：
B. Grandey;Hsiang‐He Lee;Chien Wang
中科院分区：
文献类型：
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作者：
B. Grandey;Hsiang‐He Lee;Chien Wang
抽象的。露天火灾在地球气候系统中发挥着重要作用。除了占全球二氧化碳排放量的很大一部分外，它们还是含有有机碳、黑碳和硫酸盐的大气气溶胶的主要来源。这些“火气溶胶”可以通过直接和间接的辐射效应影响气候。在本研究中，我们使用社区大气模型版本 5 (CAM5) 研究这些辐射效应和水文快速响应。火灾气溶胶的排放产生了−1.0 W m−2 的全球平均净辐射效应，主要由云对有机碳气溶胶的短波响应决定。北方地区的净辐射效应尤其强烈。传统上，许多气候模型研究都使用火气溶胶排放的年际不变的每月气候学。然而，通过比较使用年际变化排放量与年际不变排放量的模拟，我们发现忽略排放量的年际变化可能导致对火气溶胶净辐射效应强度的系统性高估。总体而言，高估了+23% (−0.2 W m−2)。从区域来看，高估的幅度可能要大得多。例如，澳大利亚和新西兰的高估值为 +58 % (−1.2 W m−2)，而北亚洲的高估值为 +43 % (−1.9 W m−2)。对火灾气溶胶净辐射效应的系统高估可能是由于气溶胶对云的非线性影响。然而，忽略排放量的年际变化似乎不会显着影响水文快速响应。为了增进对气候系统的了解，我们需要考虑气溶胶排放的年际变化。
Abstract. Open-burning fires play an important role in the earth's climate system. In addition to contributing a substantial fraction of global emissions of carbon dioxide, they are a major source of atmospheric aerosols containing organic carbon, black carbon, and sulfate. These “fire aerosols” can influence the climate via direct and indirect radiative effects. In this study, we investigate these radiative effects and the hydrological fast response using the Community Atmosphere Model version 5 (CAM5). Emissions of fire aerosols exert a global mean net radiative effect of −1.0 W m−2, dominated by the cloud shortwave response to organic carbon aerosol. The net radiative effect is particularly strong over boreal regions. Conventionally, many climate modelling studies have used an interannually invariant monthly climatology of emissions of fire aerosols. However, by comparing simulations using interannually varying emissions vs. interannually invariant emissions, we find that ignoring the interannual variability of the emissions can lead to systematic overestimation of the strength of the net radiative effect of the fire aerosols. Globally, the overestimation is +23 % (−0.2 W m−2). Regionally, the overestimation can be substantially larger. For example, over Australia and New Zealand the overestimation is +58 % (−1.2 W m−2), while over Boreal Asia the overestimation is +43 % (−1.9 W m−2). The systematic overestimation of the net radiative effect of the fire aerosols is likely due to the non-linear influence of aerosols on clouds. However, ignoring interannual variability in the emissions does not appear to significantly impact the hydrological fast response. In order to improve understanding of the climate system, we need to take into account the interannual variability of aerosol emissions.