Aerosol radiative effects on the global land carbon sink

该项目将使用最先进的卫星观测和全球模型来评估气溶胶辐射效应对陆地碳汇的作用。自工业革命以来，大气中的二氧化碳浓度增加了50%(从1750年的278ppm增加到2022年的420ppm以上)，约占气候总人为辐射强迫的80%。到目前为止，陆地和海洋碳汇吸收了人类活动排放的二氧化碳总量的一半以上，缓解了这一急剧增加的趋势(Friedlingstein等人，2022)。对这些碳汇的准确估计对于预测未来气候变化和制定有效的气候政策至关重要。然而，当前全球碳预算评估中使用的许多全球植被模型并不包括漫射光肥等重要过程的完整表示(见图1；Mercado等人，2009年；Rap等人，2018年)。因此，目前需要一个“预算不平衡”术语来结束碳预算方程式。这种碳收支失衡的巨大变异性被认为是由土地碳汇的误差造成的(Friedlingstein等人，2022年)。该项目的总体目标是提高我们对气溶胶颗粒如何影响陆地碳汇的理解。特别是，该项目将调查由于温度、降水和漫射辐射在半十年时间尺度上的变化而对陆地碳汇产生的竞争影响的作用。该方法将涉及遥感分析(例如全球生态系统动力学调查-GEDI(Hancock等人，2019年)；云和地球辐射能量系统-CERES)和模型模拟(即气溶胶、辐射和植被模型，以及英国地球系统模型-UKESM模拟)。在多样化的监督小组中，我们有能力以比以往任何时候都更全面的方式观察和模拟生物圈-大气相互作用。因此，该项目将提供一个独特的机会，利用最先进的卫星观测和全球模型来回答一系列关键问题。虽然考虑到你的兴趣相对灵活，但该项目将涉及：-使用遥感产品(例如GEDI、ICESat-2、NISAR)对全球森林结构和地上生物量密度进行全面评估。-使用卫星观测来限制模拟的半十年净初级生产力趋势，包括通过先进的计算机技术(例如偏差校正和数据驱动算法)。-探索人为气溶胶和其他污染物(例如臭氧)对UKESM模拟生态系统反馈效率的作用。-在UKESM模型中调查温度、降水和大气二氧化碳变化对生物圈-大气相互作用的影响。

This project will use state-of-the-art satellite observations and global models to evaluate the role of aerosol radiative effects on the land carbon sink. Atmospheric CO2 concentrations have increased by 50% since the Industrial Revolution (from 278ppm in 1750 to over 420ppm in 2022), contributing about 80% of the total anthropogenic radiative forcing on climate. This dramatic increase has so far been mitigated by the land and ocean carbon sinks absorbing over half of the total CO2 emitted by human activities (Friedlingstein et al., 2022). Accurate estimates of these carbon sinks is essential for projecting future climate change and developing effective climate policies. However, many global vegetation models used in current global carbon budget assessments do not include a full representation of important processes such as diffuse light fertilisation (see Fig. 1; Mercado et al., 2009; Rap et al., 2018). As a result, a "budget imbalance" term is currently needed to close the carbon budget equation. The large variability of this carbon budget imbalance is believed to be caused by errors in the land carbon sink (Friedlingstein et al., 2022). The overarching aim of the project is to improve our understanding of how aerosol particles affect the land carbon sink. In particular, the project will investigate the role of competing effects on the land carbon sink due to the variability in temperature, precipitation and diffuse radiation on semi-decadal timescales. The approach will involve a combination of remote sensing analysis (e.g. Global Ecosystem Dynamics Investigation - GEDI (Hancock et al., 2019); Clouds and the Earth's Radiant Energy System - CERES) and model simulations (i.e. aerosol, radiation and vegetation models, together with UK Earth System Model - UKESM simulations).Within the diverse supervision team we have the ability to observe and simulate biosphere-atmosphere interactions in a more comprehensive way than ever before. This project will therefore provide a unique opportunity to employ state-of-the-art satellite observations and global models to answer a series of key questions. While relatively flexible to allow for your interests, the project will involve:-A comprehensive assessment of global forest structure and above-ground biomass density using remote sensing products (e.g. GEDI, ICESat-2, NISAR).- Using satellite observations to constrain simulated semi-decadal Net Primary Productivity trends, including via advanced computer techniques (e.g. bias correction and data-driven algorithms).- Exploring the role of anthropogenic aerosol and other pollutants (e.g. ozone) on the efficiency of UKESM simulated ecosystem feedbacks.- Investigating the effect of changes in temperature, precipitation and atmospheric CO2 on biosphere-atmosphere interactions in the UKESM model.