US-Austria Cooperative Research: Evaluating Sensible Heat Flux Density above Smooth and Rough Vegetation

该奖项支持教授劳埃德W。亚利桑那大学的盖伊 与研究所的Inge Dirmhirn教授合作研究 农业大学气象、气候和应用物理系 在维也纳。 他们研究的目标是改进技术， 测量表面之间的热能的自然传递， 地球和大气层，从而提高我们的认识， 控制这种热传递的过程。 的一部分 挑战在于，在平滑上工作得相当好的技术 在粗糙的环境中，景观不能提供可靠的结果 比如森林。 他们将使用三种方法评估感热通量 在两个位置采用不同的方法， 粗糙. 他们的研究地点将是一个统一的，比较顺利 农业网站在亚利桑那州，和粗糙的橡树林网站（ Hochleitenwald）在奥地利，在那里，奥地利人已经建立了一个高架 在那19米高的森林表面建造了一座研究塔。 的 合作者为研究带来互补优势， 方法学也是如此，因为盖伊博士是鲍文比率的专家。 方法和Escherans在涡动相关方面非常有经验;两者都 小组有空气动力学模型的经验，这是第三个 他们将使用的技术。 表面和表面之间的动量、能量和质量的交换 大气对各种环境极为重要， 影响人类的现象。 努力扩大我们对 气象、水文和生态过程， 在全球范围内，需要改进评估这些交流的工具。 本文用复杂的波文比和涡动相关技术， 表面交换是目前选择的方法。 然而，在这方面， 从空基和空基遥感解译地表交换 传感器重新引起了人们对简单的空气动力学交换的兴趣 模型，尽管这些模型的早期承诺并没有得到很好的支持 应用于较粗糙的表面。 拟议的实验、绘图 在仪器和实验的实质性进展 过去十年的技术，将完善我们对表面的理解， 交换过程，并为交换的应用提供指导 模型到空气动力学粗糙的复杂表面。

This award supports Professor Lloyd W. Gay of the University of Arizona to collaborate in research with Professor Inge Dirmhirn of the Institute of Meteorology, Climatology and Applied Physics, Agricultural University of Vienna. The goal of their research is to improve the techniques for measuring the natural transfer of thermal energy between the surface of the earth and the atmosphere, and, thereby, to improve our understanding of the processes that control this transfer of heat. Part of the challenge is that techniques which work reasonably well on smooth landscapes do not provide reliable results over rougher environments such as forests. They will evaluate sensible heat flux using three different methods at two locations that offer contrasting aerodynamic roughness. Their research sites will be a uniform, relatively smooth agricultural site in Arizona, and a rougher oak forest site (the Hochleitenwald) in Austria, where the Austrians have built an elevated tower for research on the surface of that 19 meter-high forest. The collaborators bring to the research complementary strengths in methodology as well, since Dr. Gay is an expert in the Bowen ratio method and the Austrians are very experienced in eddy correlation; both groups have experience with aerodynamic models, which is the third technique they will use. The exchange of momentum, energy and mass between the surface and the atmosphere is extremely important to a variety of environmental phenomena that affect humans. Efforts to expand our knowledge of meteorological, hydrological and ecological processes from local to global scale require improved tools for evaluating these exchanges. The rather complex Bowen ratio and eddy correlation techniques for surface exchange are currently the methods of choice. However, interpretation of surface exchange from air and space-based remote sensors has generated renewed interest in simple, aerodynamic exchange models, even though early promise of these models did not hold up well in applications to rougher surfaces. The proposed experiments, drawing upon the substantial advances in instrumentation and experimental techniques of the past decade, will refine our understanding of surface exchange processes, and provide guidance for application of exchange models to aerodynamically rough, complex surfaces.