Keeping an eye on the carbon balance: linking canopy development and net ecosystem exchange using an international webcam network.
Keeping an eye on the carbon balance: linking canopy development and net ecosystem exchange using an international webcam network.
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发表时间：
2009-04
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通讯作者：
L. Wingate;A. Richardson;K. Nasahara;J. Weltzin;J. Grace
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作者：
L. Wingate;A. Richardson;K. Nasahara;J. Weltzin;J. Grace
物候事件，如春季落叶和秋季落叶，对碳和水循环的时空格局都有很强的控制作用。由于这些生命周期事件每年都受到天气模式变化的强烈影响，物候学被认为是气候变化对自然系统影响的强大整合者。现在人们认识到，需要从地方到大陆的尺度上改进对物候的监测。在世界各地俯瞰森林、牧场和湿地的FLUXNET站点上，我们发现了一个建立物候事件精确测量的机会，只需安装网络数码相机（“网络摄像头”）并记录植被冠层的每日（甚至每小时）图像。最近的一项FLUXNET调查发现，至少有28个这样的现象已经在“密切关注”冠层的发展，同时监测森林和大气之间的碳和水交换。虽然这个网络还处于起步阶段，但它似乎正在稳步增长，并且已经代表了大约58个站点年的流量和网络摄像头数据（Wingate et al., 2008）。在这里，我们介绍了这个不断增长的国际现象网络所做的努力，并举例说明了网络中的一些关键不确定性，这些不确定性现在可以使用这种多技术方法来解决。提供给我们的机会是明确的：FLUXNET站点的网络摄像头测量将揭示物候学与碳吸收之间的联系，并提供急需的来自卫星遥感（例如MODIS）的物候学产品的地面验证。这种对物候和二氧化碳净生态系统交换的多尺度监测将丰富我们对气候对物候的影响建模的理解和努力，以及物候对地球碳和能量循环的反馈对气候的影响。
Phenological events such as the spring leaf-out and the autumn fall exert a strong control on both spatial and temporal patterns of the carbon and water cycle. As these life cycle events are strongly influenced by changes in weather patterns from year to year, phenology is deemed a robust integrator of the effects of climate change on natural systems. It is now recognised that improved monitoring of phenology on local-to-continental scales is needed. At FLUXNET sites around the world overlooking forests, pastures, and wetlands, we have identified an opportunity to establish precision measurements of phenological events by simply mounting networked digital cameras (‘webcams’) and recording daily (or even hourly) images of the vegetation canopy. A recent FLUXNET survey has identified at least 28 such phenocams already ‘keeping an eye’ on canopy development whilst simultaneously monitoring carbon and water exchange between the forest and the atmosphere. Although this network is in its infancy, it appears to be growing steadily, and already represents some 58 site-years of combined flux and webcam data (Wingate et al., 2008). Here we present the efforts of this growing, international phenocam network and illustrate with examples taken from the network some of the key uncertainties that can now be tackled using this multi-technique approach. The opportunity presented to us is clear: webcam measurements at FLUXNET sites will reveal the link between phenology and carbon uptake and provide much-needed ground verification of phenology products derived from satellite remote sensing (e.g., MODIS). This multi-scale monitoring of phenology and net ecosystem exchange of CO2 will enrich our understanding and efforts at modelling not only the impacts of climate on phenology but also the impact of phenology on climate through feedbacks on the carbon and energy cycle of the planet.