Bridging Spatial Scales Using Phenological Measurements to Improve Understanding of Autumn Atmosphere-Biosphere Interactions

秋季叶片衰老的时间（着色和随后的秋天，即物候学）对中纬度陆地表面和低层大气之间的能量和碳交换具有潜在的巨大影响。然而，在植物群落水平上，秋季物候时间的空间变化尚未得到广泛的测量和分析，其潜在的环境驱动因素尚未得到很好的理解。因此，详细的秋季物候数据为评估景观水平的空间变化提供了相当大的机会，这对于精确地按比例放大到更大区域的测量或从大气环流模式缩小尺度信息至关重要。在本项目中，与小气候、碳通量和遥感测量相比，将在群落层面测量和分析秋季物候数据的空间变异性，其总体目标是提高从大陆到全球尺度的能量/碳通量估算的准确性。该项目将解决在气候学、植物生理学、生态学和遥感等领域取得重大进展的问题。秋季物候变化在空间和时间上的性质以前没有在大范围内记录过，也没有与支持测量相结合。最近的研究结果强烈表明，了解秋季植物物候发育的林分水平（~50 x 50 m）空间格局（以及驱动它们的环境过程），将与现有的春季物候数据相结合，为改善整个生长季节碳积累的景观水平估算提供关键知识。该项目产生的空间集中物候测量将为未来的近地表和卫星遥感研究提供秋季植物发育和生长的记录，包括物种差异、空间变异性和过去未记录的精确事件时间。总的来说，该项目的结果将有助于更好地了解气候变化对生物圈的影响，这将增加对未来潜在变化的认识，并可能允许更好地规划相对于预期的森林植被变化的社会影响。

The timing of leaf senescence (coloring and subsequent fall; i.e., phenology) during autumn has potentially large impacts on energy and carbon exchange between mid-latitude land surfaces and the lower atmosphere. However, spatial variations in autumn phenological timing at the plant community level have not been widely measured or analyzed, and underlying environmental drivers are not well understood. Thus, detailed autumn phenological data offer considerable opportunities for assessing landscape-level spatial variations crucial for accurate scaling-up measurements to larger areas or downscaling information from atmospheric general circulation models. In this project, spatial variability of autumn phenological data will be measured and analyzed at the community level, compared to microclimatic, carbon flux, and remote sensing measurements, with an overall goal of contributing to increased accuracy of energy/carbon flux estimates at continental to global scales.This project will address issues that are significant for advancement across the fields of climatology, plant physiology, ecology, and remote sensing. The nature of autumn phenological variability in space and time has not been previously recorded over a large area and combined with supporting measurements. Results from recent studies strongly suggest that understanding stand-level (~50 x 50 m) spatial patterns of autumn plant phenological development (and the environmental processes that drive them) will provide key knowledge needed to improve landscape level estimates of carbon accumulation across the entire growing season when combined with existing data for spring phenology. The spatially concentrated phenological measures produced by this project will provide future near-surface and satellite-derived remote sensing studies with a record of autumn plant development and growth involving species differences, spatial variability, and precise event timing that has not been recorded in the past. Overall, the results of this project will contribute to better understanding of the impacts of climate change on the biosphere, which will increase knowledge of potential future changes, and may allow for better planning relative to societal impacts of anticipated forest vegetation change.