Collaborative Research: An Optimality Principle of Evaporation over the Land Surface

合作研究：地表蒸发的最优性原理

• 批准号: 0309594
• 负责人: Rafael Bras
• 金额: $ 25.94万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0309594&HistoricalAwards=false
• 关键词: Collaborative; Research; Optimality; Principle; Evaporation

Bras0309594The working hypothesis of this research is that evaporation at the earth-atmosphere interface is always maximized, given radiative energy input in a particular environment. Under the hypothesis, evaporation is uniquely determined as a result of an optimization exercise in terms of surface temperature, surface soil moisture and sensible heat flux (a measure of turbulent transport) given an energy input.Intellectual Merits:The ideas presented here will allow the independent verification of models, will lead to improved parameterization of surface hydrology and, more importantly, will provide a framework in which the sensitivity of land evaporation to changes in radiation, earth surface properties etc. could be evaluated independently of the traditional empirical models. The research strategy includes: 1. further theoretical and empirical study to include the dependence of long wave radiation on surface temperature; 2. show the lack of sensitivity of evaporation to atmospheric moisture; 3. carry out field work to test the concepts with more appropriate data sets over bare soils; 4. investigate the validity of existing evaporation models; 5. initiate the extension of the concepts to vegetated surfaces.Broader Impacts:This work represents a broad interdisciplinary collaboration between hydrologists and ecologists with theoretical and experimental expertise. The work supports unique experimental infrastructure at the University of Iowa. Undergraduate students will have the opportunities to do theoretical and field work. Several graduate students will get their masters/doctoral degrees based on their work in this proposal. All students will be encouraged and financed to present findings in professional meetings. All work will be published in the refereed literature in a timely manner. This proposal is being submitted under the umbrella of the new MIT Earth System Initiative. This research and educational effort is intended to promote the understanding of the ``body earth'' in order to define the appropriate science to develop sound sustainability policies. The Principal Investigator is one of the leaders of this initiative, a member of its executive council, and teaches one of the require courses under the initiative's freshman core alternative program: Terrascope.

Bras0309594这项研究的工作假设是，考虑到特定环境中的辐射能量输入，地球-大气界面处的蒸发总是最大化。根据这一假设，蒸发是在给定能量输入的情况下，通过对地表温度、地表土壤湿度和感热通量（湍流传输的度量）进行优化的结果而唯一确定的。 智力优点：这里提出的想法将允许模型的独立验证将改善地表水文参数化，更重要的是，将提供一个框架，在该框架中可以独立于传统的经验模型评估土地蒸发对辐射、地球表面特性等变化的敏感性。研究策略包括：1.进一步进行理论和实证研究，包括长波辐射对表面温度的依赖性； 2.表明蒸发对大气湿度缺乏敏感性； 3. 进行实地工作，用更合适的裸土数据集来测试这些概念； 4. 研究现有蒸发模型的有效性； 5. 将概念扩展到植被表面。更广泛的影响：这项工作代表了具有理论和实验专业知识的水文学家和生态学家之间广泛的跨学科合作。这项工作支持爱荷华大学独特的实验基础设施。本科生将有机会进行理论和实地工作。一些研究生将根据他们在本提案中的工作获得硕士/博士学位。我们将鼓励并资助所有学生在专业会议上展示研究结果。所有作品将及时发表在参考文献中。该提案是在新的麻省理工学院地球系统计划的框架下提交的。这项研究和教育工作旨在促进对“地球”的理解，以便定义适当的科学来制定健全的可持续发展政策。首席研究员是该计划的领导者之一，也是其执行委员会的成员，并教授该计划的新生核心替代计划中的一门必修课程：Terrascope。