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: 0943356
• 负责人: Rafael Bras
• 金额: $ 35.32万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-05-15 至 2011-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0943356&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模拟中的应用（NSF提案0943356）布拉斯和王景峰（加州大学欧文分校）摘要本项目旨在基于最大熵产生（MEP）理论（一种新兴的非平衡系统理论框架）建立一个创新的陆面蒸散（ET）模型。这项工作的指导下，有前途的初步结果，获得地面和感热通量在干燥的陆地表面的表达式。本研究分为：（1）理论发展和（2）观测验证。的理论发展的中心任务是制定，根据我们最好的理解在大气边界层（ABL）的湍流输送，一个表达式？传递潜热的热惯性这是耗散函数的关键参数，其极值导致潜热、感热和地面热通量的MEP解。我们遵循三条线索来制定？潜热的热惯性？：(1)在大气边界层中，湍流混合对感热的输送起作用，同时也对水汽的输送起作用，（2）蒸发面上方的水汽与土壤水分处于平衡状态，（3）温度和湿度的表面变量（以及冠层上的气孔导度）足以决定蒸散的能量学。因此，？传递潜热的热惯性预计是一个函数的表面温度和湿度（和气孔导度）的情况下裸露的土壤（冠层）。 该项目的验证阶段有两个目标：（1）在局部尺度上验证裸露土壤和冠层的MEP ET模型，以及（2）探索在局部尺度（定义为Monin-Obukhov湍流模型适用的尺度）制定的MEP ET模型在区域尺度上的可能应用。在地方尺度上验证MEP模型将主要使用以前实地活动的存档数据集，并在需要时补充额外的实地测量。在区域尺度的MEP模型ET的测试将比较潜热，感热和地面热通量的MEP模型预测与再分析数据集使用其他ET模型。根据进展情况，理论发展可能会扩大到包括水（海洋，湖泊等）的情况。雪的表面。该项目如果成功实施，将提供一个新的模拟框架，用于预测局部尺度的陆地表面能量平衡，并有望产生全球覆盖的改进的地表热通量数据集。如果成功，这一努力的结果将提供一个全新的方法来计算陆地表面能量平衡，这将是简约的，需要很少的校准。该方法将在用于水文气候预测的现有陆面模型中实施。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（最好是来自弱势群体）通过进行实地实验来学习能源和水文平衡，这些实验可能会产生支持数据集。现有一整套测量能量通量和温度、土壤湿度及其他所需水文变量的仪器。所有的学生，研究生和本科生，将从事在适当的科学会议和期刊介绍他们的结果。这所大学为本科生出版一份研究刊物。高级研究员是设在欧文市加州大学工程学院的梅萨和CAMP外展计划的领导者、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机会。这一机会将用于吸引感兴趣的与会者参与与水文学和地球科学有关的问题。这些机制包括访问学校、在大学接待学生、举办公开讲座以及赞助或监督项目工作。