Early Concept for New Mission: A Spaceborne Multispectral Canopy Lidar

我们的目标这个项目旨在开发和设计一个新的卫星任务。这一新的任务概念将是一种星载多光谱冠层激光雷达(称为SPECL)，它可以测量森林的垂直轮廓，并同时确定该轮廓的光谱特征。由于激光雷达可以提供关于森林结构的非常详细的三维信息，它们在减少陆地碳循环中的不确定性和支持准确绘制土地复盖图方面具有巨大的潜力。该飞行任务的主要科学目标将是利用适当的抽样战略确定世界森林中地上生物量的全球分布，并减少与陆地生物圈有关的碳储量和通量计算中的不确定性。为什么这很重要？与林业(森林砍伐和退化)相关的温室气体约占全球排放量的17%，超过了整个全球交通网络。最近提交给首相的一份报告(2008年埃利亚施关于全球森林筹资的审查报告)预测，如果不采取行动，到2100年，仅森林砍伐造成的气候变化造成的全球经济损失就可能达到每年1万亿美元。目前，由于森林砍伐，土地利用变化造成的碳排放大部分来自热带地区，随着有机物的燃烧或腐烂，森林砍伐会将储存在生物质和土壤中的碳释放到大气中(作为二氧化碳)。因此，对土地覆盖变化的定期监测和评估对于了解自然和人为变化的程度和影响至关重要。此外，对全球碳循环的分析表明，碳的年排放量大于大气和海洋中碳的年累积量，这表明除了土地利用的变化外，陆地还存在碳的汇。值得注意的是，这一尚未解释的残余汇似乎在过去几十年中与总碳排放成比例增加，这意味着碳反馈正在相互抵消。这种平衡不太可能持续下去。SPECL任务是一个机会，既可以限制土地利用/土地利用变化造成的碳净排放量，也可以限制陆地剩余汇。在理解碳预算方面的任何进一步拖延，如果我们留下太少的时间做出回应，可能会产生严重的长期后果。我们要怎么做呢？爱丁堡率先开发了世界上第一台多光谱冠层激光雷达(专利号0808340.4)。利用CEOI的种子玉米资金，我们建造了第一台4波长激光雷达，在实验室中演示了它的使用，并对季节性反应进行了建模。一台机载MSCL(A-MSCL)仪器已于7月1日设计并提交给NERC。考虑到未来的飞行任务机会(以及所需的长时间准备时间)，迫切需要确定空间MSCL的可行性和技术准备情况。在第一个例子中，我们将为高成本但低风险的传统小卫星配置创建一个概念，成本上限为1亿GB。然后，我们将致力于将这一概念发展成超低成本(&lt；GB 500万)、快速部署(在3年内)的微型卫星平台，使用现成的组件，并在适当的情况下，使用经过验证的技术。为此，我们将考虑使用模块化CubeSat平台的高度新颖、高风险但成本非常低的选择。

Our Aim This project aims to develop and design a new satellite mission. This new mission concept will be a spaceborne multi-spectral canopy lidar (called SpeCL, 'speckle') that can measure the vertical profile of a forest and simultaneously determine the spectral characteristics of that profile. Since lidars can provide highly detailed 3D information on the structure of forest they have great potential in reducing the uncertainties in the terrestrial carbon cycle and of supporting the accurate mapping of land cover. The primary scientific objective of the SpeCL mission would be to determine the global distribution of above ground biomass in the world's forests using an appropriate sampling strategy, and to reduce uncertainties in the calculations of carbon stocks and fluxes associated with the terrestrial biosphere. Why is this important? Greenhouse gases associated with forestry (deforestation and degradation) accounts for roughly 17% of global emissions, more than the entire global transport network. A recent report to the Prime Minister (the 2008 Eliasch Review on Financing Global Forests) predicts that without action, the global economic cost of climate change caused by deforestation alone could reach $1 trillion a year by 2100. Most emissions of carbon from land-use change are currently from the tropics as a result of deforestation, which releases the carbon stored in biomass and soils to the atmosphere (as CO2) as organic matter is burned or decays. The regular monitoring and assessment of land cover change is therefore essential to understand the extent and impact of natural and anthropogenic changes Furthermore, analysis of the global carbon cycle shows that the annual emissions of carbon are larger than the annual accumulations of carbon in the atmosphere and oceans, suggesting a terrestrial sink for carbon in addition to that attributable to changes in land use. Remarkably, this as yet unexplained residual sink seems to have increased over the last decades in proportion to total carbon emissions, implying that carbon feedbacks are offsetting each other. This balance is unlikely to persist. The SpeCL mission is an opportunity to constrain both the net emissions of carbon from land-use/land-use change, and the residual terrestrial sink. Any further delay in understanding the carbon budget may have serious long term consequences if we leave too little time to respond. How will we do it? Edinburgh has pioneered the development of the world's first Multi Spectral Canopy Lidar (patent number 0808340.4). Using seedcorn funding from CEOI, we built the first 4-wavelength lidar, demonstrated its use in the lab and modelled the seasonal response. An airborne MSCL (A-MSCL) instrument has been designed and proposed to NERC on July 1st. In anticipation of future mission opportunities (and the long lead time required), there exists an imminent need for determining the feasibility and technical readiness of a spaceborne MSCL. In the first instance we will create a concept for the high cost, but low risk option of a traditional small satellite configuration with a cost ceiling of £100M. We will then aim to develop this concept to an ultra-low cost (<£5M), rapid deployment (within 3 years) micro-satellite platform using off-the-shelf components and where appropriate, 'proved' technologies. To this end we will consider the highly novel, high risk, but very low cost option of using a modular CubeSat platform.