Orographic Precipitation and Airmass Transformation

地形降水和气团转化

• 批准号: 0112354
• 负责人: Ronald Smith
• 金额: $ 79.02万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-15 至 2006-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0112354&HistoricalAwards=false
• 关键词: Orographic; Precipitation; Airmass; Transformation

An improved understanding of, and the ability to model, orographic precipitation and air mass drying would contribute to solving a number of earth science problems involving: flash flood prediction, water resources, mountain glaciers, ice core interpretation, erosion, rain-shadow deserts and inter-ocean water transport. Most current models either oversimplify or fail to resolve key moist orographic flow processes. In this research, the Principal Investigator will test existing mesoscale models and develop new theories combining airflow dynamics and microphysics.The highest priority is to compare existing model runs with data from the Mesoscale Alpine Programme (MAP). This is the only detailed data set using new technologies that allows moist air flow over a major mountain range to be diagnosed. Four MAP cases have been identified with differing characteristics. For each case, output from three numerical models will be compared with conventional and aircraft data. If the agreement is satisfactory, detailed interpretation of the output will follow. Several theoretical questions will be addressed in the analysis: the relative role of moist ascent versus flow splitting and blocking; triggered convection; the accuracy of parcel trajectories; the effect of model resolution; the testing of the "threshold" theory of precipitation efficiency; sensitivity to microphysical algorithms; and the conservation of equivalent potential temperature in mixing flows. The second phase of the research will include data and publications from three contemporary medium scale experiments managed by other groups. The results from these projects will be compared to put the MAP results into a broader context and allow cautious generalizations to be developed.In the final phase of the project, applications of relevant orographic precipitation models to other geoscience disciplines (see items above) will be undertaken, broadening the impact of the work. A scholarly survey of the field will be attempted. Considerable influence on educational programs should be seen from this research activity. Undergraduate and graduate students and post-docs will be involved in the field work and data analysis.

提高对地形降水和气团干燥的理解和建模能力，将有助于解决一些地球科学问题，包括：山洪预测、水资源、山地冰川、冰芯解释、侵蚀、雨影沙漠和大洋间的水输送。 目前大多数模式要么过于简化，要么未能解决关键的湿地形流过程。 在这项研究中，首席研究员将测试现有的中尺度模式，并开发结合气流动力学和微观物理学的新理论，最优先的是将现有的模式运行与中尺度阿尔卑斯山计划（MAP）的数据进行比较。 这是唯一一个使用新技术的详细数据集，可以诊断主要山脉上空的潮湿气流。 已确定四例MAP病例具有不同的特征。 对于每种情况，将把三种数值模型的输出与常规和飞机数据进行比较。 如果一致性令人满意，将对输出进行详细解释。 分析中将解决几个理论问题：潮湿上升与气流分裂和阻塞的相对作用;触发对流;包裹轨迹的准确性;模型分辨率的影响;降水效率“阈值”理论的测试;对微物理算法的敏感性;以及混合流中等效位温的守恒。研究的第二阶段将包括来自其他小组管理的三个当代中等规模实验的数据和出版物。 将对这些项目的结果进行比较，以便将MAP的结果置于更广泛的背景下，并进行谨慎的概括，在项目的最后阶段，将把有关的地形降水模型应用于其他地球科学学科（见上文项目），扩大工作的影响。 将尝试对该领域进行学术调查。 这一研究活动对教育方案产生了相当大的影响。 本科生、研究生和博士后将参与实地工作和数据分析。