First Simulations of Designing Stratospheric Sulfate Aerosol Geoengineering to Meet Multiple Simultaneous Climate Objectives
First Simulations of Designing Stratospheric Sulfate Aerosol Geoengineering to Meet Multiple Simultaneous Climate Objectives
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DOI：
10.1002/2017jd026874
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发表时间：
2017-12-16
影响因子：
4.4
通讯作者：
Vitt, Francis
中科院分区：
文献类型：
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作者：
Kravitz, Ben;MacMartin, Douglas G.;Vitt, Francis
我们描述了平流层硫酸盐气溶胶地球工程的第一次模拟，使用多个注入位置来满足多个同时的表面温度目标。使用CESM1(WACCM)进行了模拟，这是一个大气-海洋耦合大气环流模式，具有完全相互作用的平流层化学、动力学(包括内部产生的准两年振荡)以及硫酸盐气溶胶形成、微物理增长和沉积的复杂处理。目标被定义为在2020-2099年期间，在RCP8.5情景的背景下，将三个温度特征保持在2020年的水平。这些目标是使用反馈机制来实现的，在该反馈机制中，每年在模拟的四个位置中的每一个位置的二氧化硫注入速率都被独立地调整。即使在存在不确定性、非线性和可变性的情况下，目标也能实现，主要是通过在北纬30度和南纬30度喷注SO2。到最后一年的模拟，反馈算法要求每年51Tg SO2的总喷射率。注入不在热带地区，这导致地面气候响应与注入量之间的线性程度高于许多以前在赤道进行注入的研究中发现的。由于目标是根据年平均温度定义的，因此所需的土工工程会导致夏季过冷和冬季过冷。与对应于2020年的参考值相比，水文循环也被抑制。我们在这项研究中描述的演示是了解地球工程能做什么和不能做什么的重要一步。通俗易懂的概述了解地球工程能做什么和不能做什么对于缩小未来气候变化潜在反应范围的不确定性至关重要。这项工作的一部分是为了证明在气候反应存在不确定性的情况下，在气候模型中满足特定气候目标的能力。在这里，我们首次展示了通过平流层硫酸盐气溶胶地球工程实现三个同时全球温度目标的战略，该战略使用最先进的气候模型，该模型代表了与潜在气候反应相关的关键过程。我们展示了使用我们开发的算法可以成功地实现这些目标，并且我们还展示了一些潜在的副作用，这些可能是我们无法控制的潜在目标。
We describe the first simulations of stratospheric sulfate aerosol geoengineering using multiple injection locations to meet multiple simultaneous surface temperature objectives. Simulations were performed using CESM1(WACCM), a coupled atmosphere-ocean general circulation model with fully interactive stratospheric chemistry, dynamics (including an internally generated quasi-biennial oscillation), and a sophisticated treatment of sulfate aerosol formation, microphysical growth, and deposition. The objectives are defined as maintaining three temperature features at their 2020 levels against a background of the RCP8.5 scenario over the period 2020-2099. These objectives are met using a feedback mechanism in which the rate of sulfur dioxide injection at each of the four locations is adjusted independently every year of simulation. Even in the presence of uncertainties, nonlinearities, and variability, the objectives are met, predominantly by SO2 injection at 30 degrees N and 30 degrees S. By the last year of simulation, the feedback algorithm calls for a total injection rate of 51Tg SO2 per year. The injections are not in the tropics, which results in a greater degree of linearity of the surface climate response with injection amount than has been found in many previous studies using injection at the equator. Because the objectives are defined in terms of annual mean temperature, the required geongineering results in overcooling during summer and undercooling during winter. The hydrological cycle is also suppressed as compared to the reference values corresponding to the year 2020. The demonstration we describe in this study is an important step toward understanding what geoengineering can do and what it cannot do.Plain Language Summary Understanding what geoengineering can and cannot do is crucial for narrowing uncertainties in the range of potential responses to future climate change. Part of this effort is to demonstrate the capability of meeting specified climate objectives in a climate model in the presence of uncertainty in climate response. Here we provide the first demonstration of a strategy for meeting three simultaneous global temperature objectives via stratospheric sulfate aerosol geoengineering, using a state-of-the-art climate model that represents key processes relevant to the potential climate responses. We show that the objectives can be met successfully using an algorithm we have developed, and we also demonstrate some potential side effects, which could be potential objectives for which we did not control.