MSA: Rapid assessment of the carbon cycle consequences of ecosystem disturbances

光合作用是植物利用阳光中的能量来驱动其生长和消耗大气中的二氧化碳的过程。这是一项重要的生态系统活动，对火灾和其他经常迅速发生的极端事件高度敏感。2020年美国野火季节是有记录以来最严重的，重要的是要了解生态系统如何应对这种干扰。长期以来，美国一直是地球静止卫星（通常称为气象卫星）发展的领导者，这些卫星每隔几分钟测量一次地面和大气层。地球静止运行环境卫星（GOES）上的一种名为高级基线成像仪（ABI）的新传感器现在可以进行与光合作用有关的测量，并且几乎可以在真实的时间内进行测量。在同类研究中，这项研究将使用ABI观测来测量生态系统的碳消耗，并将其与美国近50个地点的国家生态观测网络（氖）的传感器进行的地面测量进行比较。这些观测结果将用于了解不同生态系统的生态系统碳吸收的日常模式，以及它如何在应对极端事件，特别是野火时迅速变化。该项目还将为受到最近旅行中断影响的高中生创建教育材料和“虚拟实地考察”，并培训美国原住民大学生使用环境开源数据。总初级生产力（GPP）通常使用生态系统尺度上半小时时间尺度的涡动协方差进行测量，并使用极坐标“升级”到更大的区域。轨道卫星创建回顾每周到年度产品。新的地球观测环境系统ABI以约1公里的像素大小测量地表的可见光和近红外反射率，因此可以测量归一化差异植被指数和其他指数，以分钟为时间尺度从空间估计全球初级生产力。GOES长期以来一直用于监测极端事件，估计生态系统的水和温度压力，并测量直接和散射太阳辐射，所有这些都是全球PP的重要驱动因素。换句话说，GPP现在可以以分钟的时间尺度和类似于中分辨率成像光谱仪（MODIS）的空间分辨率进行近实时测量，但迄今为止，这一机会仍未被探索。该项目将测试以下假设：1）漫射光合有效辐射（PAR）是基于卫星的GPP估计的必要输入，因为它比直接PAR更有效地照亮树冠体积，2）2020年加州野火降低了附近氖塔的GPP，因为烟雾降低了总PAR，和3）2020年科罗拉多野火附近氖塔的GPP被更大比例的散射PAR增强。解决这些假设将提高对极端事件对碳循环的直接影响的理解。项目材料也将用于为高中生创建课程，接下来-该奖项反映了NSF的法定使命，并被认为是值得通过使用基金会的智力价值和更广泛的评估来支持的。影响审查标准。

Photosynthesis is the process by which plants use energy from sunlight to power their growth and consumption of carbon dioxide from the atmosphere. It is a critical ecosystem activity that is highly sensitive to fire and other extreme events that often occur quickly. The 2020 United States wildfire season was the most severe on record and it is important to understand how ecosystems respond to such disturbances. The United States has long been a leader in the development of geostationary satellites – commonly known as weather satellites – that measure the ground and atmosphere every few minutes. A new sensor called the Advanced Baseline Imager (ABI) on the Geostationary Operational Environment Satellites (GOES) can now make measurements related to photosynthesis and can do so nearly in real time. In the first study of its kind, this research will measure ecosystem carbon consumption using ABI observations and compare it to ground-based measurements made by sensors that are part of the National Ecological Observation Network (NEON) in nearly 50 sites across the United States. These observations will be used to understand the daily pattern of ecosystem carbon uptake across different ecosystems and how it can change rapidly in response to extreme events, especially wildfires. This project will also create educational materials and ‘virtual field trips’ for high school students who have been disproportionally impacted by recent travel disruptions, and to train groups of Native American undergraduates in the use of open source data on the environment.Gross primary productivity (GPP) is often measured using eddy covariance on half-hourly timescales at the ecosystem scale and ‘upscaled’ to larger regions using polar-orbiting satellites to create retrospective weekly to annual products. The new GOES ABI measures visible and near-infrared reflectance at the surface at a pixel size of ~1 km and can thus measure the normalized difference vegetation index (NDVI) and other indices to estimate GPP from space at time scales of minutes. GOES has long been used to monitor extreme events, to estimate ecosystem water and temperature stress, and to measure direct and diffuse solar radiation, all of which are important drivers of GPP. In other words, GPP can now be measured in near real-time at time scales of minutes and at spatial resolutions similar to the Moderate Resolution Imaging Spectroradiometer (MODIS), yet this opportunity has remained unexplored to date. This project will test the hypotheses that 1) diffuse photosynthetically active radiation (PAR) is a necessary input for satellite-based GPP estimates because it illuminates the canopy volume more efficiently than direct PAR, 2) that the 2020 California wildfires decreased GPP at nearby NEON towers because smoke decreased total PAR, and 3) that the GPP at NEON towers near the 2020 Colorado wildfires was enhanced by a greater fraction of diffuse PAR. Addressing these hypotheses will improve understanding of the immediate impacts of extreme events on carbon cycling. Project materials will also be used to create lessons for high school students that follow Next-Generation Science Standards and will train undergraduate students from Tribal Colleges on environmental data science early in their college careers when attrition from STEM fields tends to be high among all students.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.