An Application of the Theory of Maximum Entropy Production in Modeling Evapotranspiration

最大熵产生理论在蒸散发模拟中的应用

• 批准号: 1138611
• 负责人: Rafael Bras
• 金额: $ 35.32万
• 依托单位: Georgia Tech Research Corporation
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-05-01 至 2015-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1138611&HistoricalAwards=false
• 关键词: Application; Theory; Maximum; Entropy; Production

An Application of the Theory of Maximum Entropy Production in ModelingEvapotranspiration(NSF Proposal 0943356)PIs: Rafael L. Bras and Jingfeng WangUniversity of California, IrvineAbstractThis project aims at developing an innovative model of evapotranspiration (ET) over land surfaces based on the theory of maximum entropy production (MEP), an emerging theoretical framework for non-equilibrium systems. The effort is guided by promising preliminary results that obtained expressions for ground and sensible heat fluxes over a dry land surface. The research is organized in: (1) theoretical development and (2) observational validation. The central task of the theoretical development is to formulate, based on our best understanding of the turbulent transport in the atmospheric boundary layer (ABL), an expression for the ?thermal inertia for transferring latent heat? that is the key parameter of the dissipation function whose extremization leads to the MEP solution of latent, sensible and ground heat fluxes. We follow three leads in formulating the ?thermal inertia for latent heat?: (1) the turbulent mixing responsible for the transport of sensible heat in the ABL is also responsible for the transport of water vapor, (2) water vapor right above the evaporating surface is in equilibrium with the soil water, and (3) the surface variables of temperature and humidity (as well as stomatal conductance over the canopy) are sufficient to determine the energetics of the evapotranspiration. As a result, the ?thermal inertia for transferring latent heat? is expected to be a function of surface temperature and humidity (and stomatal conductance) for the case of bare soil (canopy). The validation phase of the project has a two-fold objective: (1) validating the MEP model of ET for bare soil and canopy at local scales, and (2) exploring a possible application of the MEP model of ET formulated at local scale (defined as the scales at which the Monin-Obukhov turbulence model applies) to regional scales. Validation of the MEP model at local scales will mostly use archived datasets from previous field campaigns supplemented by additional field measurements whenever needed. Test of the MEP model of ET at regional scales will compare latent, sensible, and ground heat fluxes predicted by the MEP model with the reanalysis datasets using other ET models. Depending on progress, the theoretical development may expand to include the case of water (oceans, lakes, etc.) and snow surfaces. The project, if successfully carried out, will provide a new modeling framework for predicting the land surface energy balance at local scales and hopefully producing improved datasets of surface heat fluxes with global coverage.If successful the results of this effort will provide a completely new method to compute the land surface energy balance that would be parsimonious and require little calibration. The method will be implemented in existing land surface models that are used to make hydro-climatic predictions. Besides engaging doctoral students in the effort, the project will use an existing undergraduate research opportunities program to engage at least one undergraduate student, preferably from a disadvantaged group, in learning energy and hydrologic balances by performing field experiments that could yield supporting data sets. A complete set of instruments to measure energy fluxes and temperature, soil moisture and other hydrologic variables required are available. All students, graduate and undergraduate, will be engaged in presenting their results in appropriate scientific meetings and journals. The University publishes a research journal for undergraduates. The senior investigator is a leader, host and participant of the MESA and CAMP outreach programs housed at the school of engineering of the University of California, Irvine. This provides access to underprivileged students in middle and high schools as well as community colleges. This access will be used to engage interested participants in issues related to hydrology and earth sciences. Mechanisms include visits to schools, receiving students at the university, giving public lectures and sponsoring or supervising project work.

最大熵产生理论在蒸散量建模中的应用（NSF 提案 0943356）PIs：Rafael L. Bras 和 Jingfeng Wang 加州大学欧文分校摘要该项目旨在基于最大熵产生 (MEP) 理论（一种新兴的理论框架）开发地表蒸散量 (ET) 的创新模型。 非平衡系统。这项工作以有希望的初步结果为指导，这些结果获得了干燥土地表面地面和感热通量的表达式。该研究分为：（1）理论发展和（2）观察验证。理论发展的中心任务是基于我们对大气边界层（ABL）中湍流传输的最佳理解，制定“传递潜热的热惯性”的表达式。这是耗散函数的关键参数，其极值化导致潜热通量、感热通量和地热通量的 MEP 解。我们遵循三个线索来公式化“潜热的热惯性”：（1）负责 ABL 中显热传输的湍流混合也负责水蒸气的传输，（2）蒸发表面正上方的水蒸气与土壤水处于平衡，以及（3）温度和湿度的表面变量（以及冠层上的气孔导度）足以确定 蒸散量。结果，“传递潜热的热惯性”？对于裸露土壤（冠层），预计是表面温度和湿度（以及气孔导度）的函数。 该项目的验证阶段有两个目标：（1）验证局部尺度裸土和冠层的蒸散MEP模型，（2）探索局部尺度（定义为莫宁-奥布霍夫湍流模型应用的尺度）制定的蒸散MEP模型在区域尺度的可能应用。地方规模的 MEP 模型验证将主要使用以前实地活动的存档数据集，并在需要时辅以额外的实地测量。在区域尺度上对 ET 的 MEP 模型进行测试，将 MEP 模型预测的潜热、感热和地热通量与使用其他 ET 模型的再分析数据集进行比较。根据进展，理论发展可能会扩展到包括水（海洋、湖泊等）和雪面的情况。该项目如果成功实施，将提供一个新的建模框架，用于预测局部尺度的地表能量平衡，并有望产生覆盖全球的改进的地表热通量数据集。如果成功，这项工作的结果将提供一种全新的方法来计算地表能量平衡，该方法将是简约且几乎不需要校准的。该方法将在用于进行水文气候预测的现有陆地表面模型中实施。除了让博士生参与这项工作外，该项目还将利用现有的本科生研究机会计划，让至少一名本科生（最好来自弱势群体）通过进行可产生支持数据集的现场实验来学习能源和水文平衡。提供一整套测量能量通量和温度、土壤湿度和其他所需水文变量的仪器。所有学生，无论是研究生还是本科生，都将在适当的科学会议和期刊上展示他们的成果。该大学为本科生出版一份研究期刊。这位高级研究员是加州大学欧文分校工程学院 MESA 和 CAMP 外展项目的领导者、主持人和参与者。这为初中和高中以及社区大学的贫困学生提供了入学机会。该访问权限将用于吸引感兴趣的参与者参与水文学和地球科学相关问题。机制包括参观学校、接待大学学生、进行公开讲座以及赞助或监督项目工作。