Upscaling of greenhouse gas emissions from freshwater wetlands

21世纪最重要的全球环境和政策问题是人为引起的气候变化，迫切需要关于温室气体源和汇的定量信息；事实上，2015年巴黎气候大会（COP21）达成的国际协议强调，需要“现有的最佳科学”来帮助降低大气中温室气体的增长率。不幸的是，我们对一些主要的全球自然温室气体源和汇的量化存在严重差距，北部湖泊和湿地代表了这样一个正在进行的辩论。我们知识的这些局限很大程度上反映了进行测量的必要技术。量化温室气体通量的两种基本方法称为“室”通量技术和“涡动相关”通量技术；前者是一项成熟的技术，它涉及在陆地或水域上放置一个小室，并监测室内气体浓度随时间的变化。第二种是EC方法，它依赖于将向上和向下的气流（涡流）中的微小浓度差异相加，从而得出净系统通量。两种制度各有优缺点；例如，腔室系统只能测量小区域，并且建造和操作成本很高，而EC系统可以提供大面积（平方公里）的通量，但不能分解到“热点”或实验地块尺度上的点源。在最近的NERC资助下，约克大学的科学家们基于在重大体育赛事中移动头顶摄像机的技术，开发了一种全新的测量方法。该系统可以在大型测量场所的任何地方快速放置一个腔室或一件重型设备，精度达到几毫米，使用精密控制的绞车，在预编程计算机的自动控制下，连续工作。因此，该系统可以在时间和空间上提供高度重复的测量，克服了现有方法的许多问题。目前的赠款的目的是在世界上最主要和装备最好的温室气体监测点之一（瑞典的Foljesjon湖）建立这样一个系统，在那里，关于来自这个内陆湖的大量温室气体通量的主要来源存在重大未解决的问题。由于在这种地形下工作的固有困难，英国团队被邀请在现场协同工作。由此产生的国际团队将测量来自湖泊的详细温室气体交换，确定特定的植被类型、开阔水域、特定的沉积物类型等是否是观测到的气体通量（例如甲烷）的主要热点。我们的漫游设备将日夜工作，在任何天气条件下，并将是世界上独一无二的，通过全面访问现有的复杂基础设施（例如现场的三相电力，现场住宿和车辆，当地工程支持，访问现有数据集）以及最先进的传感器（例如多光谱扫描仪，精密激光器）来支持我们的新系统头部的测试“飞行”。提供了关于湖泊结构和植被的前所未有的准确数据。如果我们在这种困难的环境中成功地证明了这项技术，那么类似的系统很可能在世界各地被采用（例如火山、农业研究），从而产生全新的、基于英国的环境监测技术和专业知识。国际机会基金（IOF）计划旨在使nerc资助的研究人员能够与海外科学家建立长期合作伙伴关系，为目前nerc资助的科学增加价值；这正是当前工作的目的，由此产生的合作解决了一个关键的全球问题，任何一个小组都不能单独回答，并启动了两个高度互补的研究小组潜在的长期合作。

The single most important global environmental and policy concern in the 21st century is that of human-induced climate change, with an urgent need for quantitative information about the sources and sinks of the responsible greenhouse gases (GHGs); indeed, the international agreements from the 2015 Paris climate conference (COP21) emphasised the need for "the best available science" to aid in reducing atmospheric GHG growth rates. Unfortunately, there are serious gaps in our quantification of some major global natural sources and sinks of GHGs, and northern lakes and wetlands represent one such on-going debate. These limitations to our knowledge are largely a reflection of the necessary technologies for making the measurements. The two basic methods for quantifying GHG fluxes are called 'chamber' and 'eddy covariance (EC)' flux techniques; the former is a well-established technology which involves placing a small chamber over a land or water area and monitoring the gas concentration changes inside the chamber over time. The second, EC approach, relies upon summating small concentration differences in upward and downward air gusts (eddies) to derive a net system flux. Both systems Have their failings and advantages; for example, chamber systems only measure over small areas and are expensive to build and operate, whilst EC systems can provide a flux for a large area (km2) but cannot resolve down to locate point sources at the 'hotspot' or experimental plot scale. Under recent NERC funding, scientists at York have developed a totally new measurement approach, based on the technique used to move overhead cameras at major sports events. The system can rapidly place a chamber, or piece of heavy equipment, anywhere in a large measurement arena, to an accuracy of a few mms, achieved using precision-controlled winches, under the automatic control of a pre-programmed computer, and working continuously. The system can therefore provide highly replicated measurements in time and space, overcoming many of the problems of existing methods. The current grant is targeted at establishing such a system at one of the leading, and best equipped, GHG monitoring sites in the world (Lake Foljesjon, Sweden), where there are major unresolved questions about the key sources of the large GHG fluxes coming from this inland lake. The UK team have been invited to work collaboratively at the site because of the inherent difficulties of working in this terrain. The resulting international team will measure detailed GHG exchanges from the lake, identifying whether specific vegetation types, open water, specific sediment types etc. are the major hotspots for the observed gases fluxes (e.g. methane). Our roving equipment will work day and night, under all weather conditions, and will be unique throughout the world supported by full access to the existing sophisticated infra-structure (e.g. 3 phase electricity at the site, field accommodation and vehicles, local engineering support, access to existing datasets) as well as state-of-the-art sensors (e.g multi-spectral scanners, precision lasers) for test 'flying' on the head of our novel system, enabling unprecedented and accurate data about the structure of the lake and it's vegetation. If we successfully prove the technology in this difficult environment then similar systems could well be adopted around the world (e.g volcanos, agricultural research) leading to entirely new, UK-based, environmental monitoring technology and expertise. The International Opportunities Fund (IOF) scheme is designed to enable NERC-supported researchers to build long-term partnerships with overseas scientists, add value to current NERC-funded science; this is precisely the aim of the current work, with the resulting collaboration addressing a key global question neither group can answer alone, and initiating a potentially long-lived dovetailing of two highly complementary research groups.