Pre-Launch Development of Sentinel-3 SLSTR Active Fire Product

海陆表面温度辐射计(SLSTR)是欧空局于2013年至2025年在哨兵3号卫星上发射的一台新仪器。Sentinel-3是一项海洋和中分辨率陆地任务，主要致力于提供数据，以推动全球环境与安全监测(GMES)业务服务，并为科学应用提供不变的数据。SLSTR建立在传统(A)ATSR系列仪器的基础上，具有对地球海洋、陆地表面和大气进行长期、高辐射性能观测的独特能力。然而，SLSTR从一开始就被专门设计成对海洋、大气和陆地进行高质量的观测，包括与活跃燃烧的火灾有关的观测。主动火灾信息是全球气候观测系统(GCOS)指定的基本气候变量(ECV)之一，用于支持对土地变化动态及其对气候的影响的全球一致监测，以便适当更新对《气候公约》的气候变化估计。据信，植被火灾每年向大气排放的碳量约为化石燃料燃烧所致碳排放量的40%，这一事实说明了这一重要性。全球气候观测系统实施计划是落实联合国公约的最先进的地球观测框架。该计划强调需要对陆地领域的13个基本气候变量(ECV)进行业务观测；其中包括火灾扰动。有鉴于此，SLSTR仪器的许多规格特别适用于提供必要的辐射观测，以提供关于活跃火灾地点的有用信息，最重要的是包括两个以3.7微米和10.8微米为中心的新辐射“火灾”通道，这两个通道具有低增益、宽动态范围设置，可防止即使是最强烈的火灾也被饱和。因此，SLSTR有能力在全球范围内交付第一个可供使用的实战主动火力产品。该建议旨在通过开发、评估和测试从该仪器提供优化的、高质量的主动火灾产品所需的一系列算法，包括火灾位置、时间和具有量化不确定性的火灾辐射功率(FRP)输出，最大限度地提高科学效益和英国和欧空局在SLSTR上的投资回报。根据这些信息，可以计算植被燃料消耗、碳、微量气体和气溶胶释放的速率，以及随后得出的其他参数。预计应用这些算法产生的业务产品将用于全球环境和环境监测系统的业务服务，如设想从当前欧洲气象中心牵头的全球环境监测系统项目发展而来的大气服务，以及国家机构，如英国气象局，以及广泛的科学应用，包括与碳循环科学和大气成分研究有关的科学应用。例如，业务机构目前在欧洲和非洲上空使用的地球静止活跃火和PI开发的玻璃钢产品证明了这类数据对空气质量警告的近实时羽流预报的价值。如果没有时间和必要的支助来开发和测试专门用于SLSTR的一套算法，根据该仪器测量的辐射得出的任何火焰产品将仅限于为其他传感器开发的现有算法的端口，因此将无法利用SLSTR的独特能力[例如其双视能力和火焰适应的光谱通道]及其在携带一套补充仪器的哨兵3号卫星上的位置。这一NCEO任务支持项目将确保我们能够从SLSTR提供最佳的主动火力信息，用于科学应用和作战服务。

The Sea and Land Surface Temperature Radiometer (SLSTR) is a new ESA instrument flying on the Sentinel-3 satellites from 2013 to 2025. Sentinel-3 is an Ocean and Medium-Resolution Land Mission primarily dedicated to delivering data to drive Global Monitoring for Environment and Security (GMES) Operational Services, as well as providing invariable data for science applications. SLSTR builds on the heritage (A)ATSR series of instruments, having unique capabilities for long-term, high radiometric performance observation of Earth's oceans, land surface and atmosphere. However, SLSTR has been designed from the start specifically to make high quality observations of the ocean, atmosphere and land, including in relation to actively burning fires. Active Fire information is one of the Essential Climate Variables (ECVs) designated by the Global Climate Observing System (GCOS) as required for supporting consistent global monitoring of land change dynamics and their impacts on climate, in order that climate change estimates for the UNFCCC maybe properly updated. The importance is illustrated by the fact that vegetation fires are believed to emit an annual amount of carbon to the atmosphere that is estimated as perhaps 40% of that due to fossil fuel burning. The Implementation Plan of GCOS is the most advanced Earth Observation framework for implementing a UN convention. The plan emphasizes the need for operational observations for thirteen Essential Climate Variables (ECV) in the terrestrial domain; among them Fire Disturbance. In view of this, a number of the specifications of the SLSTR instrument have been especially adapted for providing the necessary radiometric observations for delivering useful information over active fire locations, most importantly the inclusion of two new radiometric 'fire' channels centered on 3.7 microns and 10.8 microns that have low-gain, wide dynamic range settings that prevent saturation over even the most intensely burning fires. SLSTR therefore has the capability to deliver the first operational active fire product available at the global scale. The proposal aims to maximize the scientific benefit and the return on UK and ESA investment in SLSTR by developing, evaluating and and testing the series of algorithms necessary to deliver an optimized, high quality Active Fire product from this instrument, including fire location, time and fire radiative power (FRP) output with quantified uncertainties. From this information rates of vegetation fuel consumption, carbon, trace gas and aerosol release can be calculated, along with other subsequently derived parameters. It is expected that an operational product resulting from application of these algorithms would find use in both operational GMES Services, such as the Atmospheric Service envisaged as developing from the current ECMWF-led GEMS project, and by National Agencies such as the UK Met Office, and in a wide variety of science applications including those related to carbon cycle science and studies of atmospheric constituents. Current use by operational agencies of geostationary Active Fire and FRP products developed by the PI over Europe and Africa have demonstrated the value of such data for near-real time plume forecasting in relation to air quality warnings for example. Without the time and support necessary to develop and test a suite of algorithms specifically for SLSTR, any fire product derived from the radiances measured by the instrument will be limited to ports of existing algorithms developed for other sensors and so will fail to make use of the unique capabilities of the SLSTR [such as its dual view capability and fire-adapted spectral channels] and its position on the Sentinel-3 satellite carrying a suite of complementary instruments. This NCEO Mission Support project will ensure our ability to deliver optimum active fire information from SLSTR for use in both science applications and operational services.