Vegetation feedbacks on atmospheric moisture and heat transport

植被对大气水分和热量传输的反馈

• 批准号: 261519-2007
• 负责人: Cowling, Sharon
• 金额: $ 1.32万
• 依托单位: University of Toronto
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2011
• 资助国家: 加拿大
• 起止时间: 2011-01-01 至 2012-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=479863
• 关键词: Vegetation; feedbacks; atmospheric; moisture; heat

Although most often associated with the carbon cycle, terrestrial vegetation can also have a profound influence on the Earth's hydrological and surface energy budgets. Plants release water into the atmosphere via transpiration, and as a result can influence the partitioning of surface energy into sensible and latent heat. Latent heat is a form of potential energy that results in the use of energy for vaporization of water, wherein the latent energy can be moved to distant areas and released upon condensation. Production of latent energy therefore is a means by which atmospheric heat and moisture is transported to cooler places across the globe. Recent research in my lab indicates that if vegetation in northern latitudes, like in the Canadian boreal forest and tundra, were to be more productive (say as a result of increasing atmospheric CO2), then the extra production of latent heat that they would produce could represent a potential positive feedback on Arctic warming. This proposal is aimed at getting a better understanding of how vegetation can influence atmospheric transport of moisture and heat. This research is made all the more critical because satellite research has already shown that northern latitudes are much greener now than they were over a decade ago. If this greening also results in an increase in latent heat production, then we should be prepared for an even greater magnitude of warming. It is unwise of us to overlook positive (warming) feedbacks because they can lead to "climate surprises" and threshold-induced rapid rates of climate change.

虽然陆地植被通常与碳循环有关，但也可对地球的水文和地表能量收支产生深远影响。植物通过蒸腾作用将水分释放到大气中，因此可以影响表面能量分配为感热和潜热。潜热是导致能量用于水的蒸发的势能的一种形式，其中潜热可以移动到远处的区域并在冷凝时释放。因此，潜在能量的产生是一种将大气热量和水分输送到地球仪上较冷地方的手段。我的实验室最近的研究表明，如果北方纬度的植被，如加拿大北方森林和苔原，更有生产力（比如由于大气中二氧化碳的增加），那么它们产生的额外潜热可能会对北极变暖产生潜在的积极反馈。该提案旨在更好地了解植被如何影响大气中的水分和热量输送。这项研究变得更加重要，因为卫星研究已经表明，北方纬度现在比十多年前更加绿色。如果这种绿化也导致潜热产生的增加，那么我们应该为更大幅度的变暖做好准备。我们忽视积极的（变暖）反馈是不明智的，因为它们可能导致“气候惊喜”和阈值引起的快速气候变化。