The Bulk Aerodynamic Method for Heat Flux Based on Surface Radiation Temperature

基于表面辐射温度的整体空气动力学热通量计算方法

• 批准号: 9417959
• 负责人: Jielun Sun
• 金额: $ 23.28万
• 依托单位: University of Colorado at Boulder
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-11-01 至 1999-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9417959&HistoricalAwards=false
• 关键词: Bulk; Aerodynamic; Method; Heat; Flux

Jielun Sun & L. Mahrt/Abstract ATM-9417959 The surface radiative temperature is the only available surface temperature in most large scale field programs and is therefore used to estimate the vertical temperature difference in the bulk aerodynamic relationship. In many numerical models, the vertical temperature difference is estimated in terms of radiative surface temperature computed from the surface energy balance. Both of these applications generally retain existing similarity theory even though such similarity theory is appropriate only for the temperature at the roughness height. Several recent studies have shown that the combination of surface radiative temperature with existing similarity theory can lead to large errors, counter gradient fluxes and/or absurdly small values of the roughness height for heat. This document research proposes to ameliorate these problems by considering modification of existing similarity theory and relationships between the surface radiation temperature and the aerodynamic surface temperature. These developments must be preceded by replacing the value of the surface radiative temperature with a function of the microscale distribution of the surface radiative temperature. As one example, appropriate weighting of the temperature of hot dry ground, partially covered by transpiring vegetation, should eliminate cases of countergradient heat transport. Several models and measurement schemes or representing the microscale distribution of surface radiation temperature are proposed. The data analysis will take advantage of existing tower and aircraft observations from a number of field programs. In addition, more focused measurements of the microscale distribution of surface radiative temperature will be implemented along with flux measurements from the NCAR ASTER System. The bulk aerodynamic formulation will be re-evaluated in terms of the improved representation of the surface radiation temperature. Special attention will be given to problems associated with the free convection case of nearly vanishing mean flow and the case of spatially- averaged fluxes under weak wind conditions.

Jielun Sun＆L。Mahrt/Abstract ATM-9417959表面辐射温度是大多数大规模野外程序中唯一可用的表面温度，因此用于估计整体空气动力学关系中的垂直温度差。 在许多数值模型中，根据表面能平衡计算的辐射表面温度估算了垂直温度差。 尽管这种相似性理论仅适用于粗糙度高度的温度，但两种应用通常都保留了现有的相似性理论。 最近的一些研究表明，表面辐射温度与现有相似性理论的结合可能导致较大的误差，反梯度通量和/或荒谬的粗度高度值。 本文档研究建议通过考虑修改现有相似性理论以及表面辐射温度与空气动力表面温度之间的关系来改善这些问题。 这些发展必须先于取代表面辐射温度的显微镜分布的函数代替表面辐射温度的值。 作为一个例子，热干地的温度的适当加权，部分被蒸发植被覆盖，应消除相反的热传输案例。 提出了几种模型和测量方案或表示表面辐射温度的显微镜分布。 数据分析将利用许多现场计划中现有的塔楼和飞机观测。 此外，将实施更集中的表面辐射温度显微镜分布的测量结果，并与NCAR Aster System的通量测量一起实施。 根据表面辐射温度的改善表示，将重新评估批量空气动力学配方。 将特别注意与几乎消失的平均流量和在弱风条件下的空间平均通量相关的自由对流案例相关的问题。