Collaborative Research: Investigating the Characteristics of Lower Tropospheric Airborne GPS Radio Occultation Observations and Their Impact in Hurricane Studies

合作研究：调查低对流层机载 GPS 无线电掩星观测的特征及其对飓风研究的影响

• 批准号: 1015904
• 负责人: Jennifer Haase
• 金额: $ 32.04万
• 依托单位: Purdue University
• 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: 2010-09-15 至 2013-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1015904&HistoricalAwards=false
• 关键词: Collaborative; Research; Investigating; Characteristics; Lower

The hurricane genesis process is known to depend on the degree of vertical instability needed to support deep convection and on mid-level moistening, which modulates convective activity. However, the time variation of moistening is poorly known due to the lack of high temporal and spatial observations during the genesis process. Global Positioning System (GPS) Radio Occultation (RO) provides area-averaged profiles of refractivity (which depends on moisture and temperature) with very high vertical resolutions that are complementary to dropsondes (pointwise, high vertical resolution) and satellite retrievals (high horizontal but poor vertical resolution). GPS RO is insensitive to heavy precipitation, clouds, and winds. Since the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC) became operational, space borne GPS RO data have shown a positive impact on global numerical weather prediction models in the mid to upper troposphere range. However, the use of the data at lower levels has lagged for several reasons: 1) complications due to strong horizontal variations in moisture 2) difficulties in signal tracking and 3) sparse observations within the window of interest for mesoscale systems. This has led to minimal impact in tropical cyclone genesis and forecasting, and minimal impact below mid-troposphere in general. Airborne RO can play a major role in advancing understanding of the hurricane genesis process, because dense targeted measurements are simpler to make with an airborne system than with the existing space borne constellation. The PIs will take advantage of a unique opportunity to collect data during the Pre-Depression Investigation of Cloud Systems of the Tropics (PREDICT) campaign in August 2010, which will allow them to test their progress in data assimilation for the case of tropical cyclone genesis. The data assimilation results should be of great interest to PREDICT investigators because they will provide better initial conditions for high-resolution models for testing new hypotheses concerning the evolution of tropical disturbances into hurricanes. Broader Impacts: The project will promote the use of airborne radio occultation to an expanded research community and serve as a feasibility test for hurricane hunter surveillance missions, potentially resulting in a direct societal benefit from improved operational forecasts. This research activity will educate graduate students and promote the advancement of postdoctoral researchers within an international collaborative structure between Taiwan and US universities. It will strengthen research programs led by four female investigators, who will serve as role models for their students as well as other young female scientists.

众所周知，飓风的形成过程取决于支持深层对流所需的垂直不稳定程度，以及调节对流活动的中层湿润程度。然而，由于缺乏对其成因过程的高时空观测，人们对其润湿的时间变化知之甚少。全球定位系统（GPS）无线电掩星（RO）提供区域平均折射率剖面（取决于湿度和温度），具有非常高的垂直分辨率，是对下投探空仪（点向，高垂直分辨率）和卫星检索（高水平但低垂直分辨率）的补充。GPS RO对强降水、云和大风不敏感。自COSMIC星座气象、电离层和气候观测系统（Constellation Observing System for Meteorology, Ionosphere and Climate， COSMIC）投入使用以来，星载GPS RO数据对全球对流层中高层数值天气预报模式产生了积极影响。然而，由于以下几个原因，较低水平数据的使用滞后：1)由于强烈的水汽水平变化引起的复杂性；2)信号跟踪困难；3)中尺度系统感兴趣窗口内的稀疏观测。这导致对热带气旋形成和预报的影响很小，对对流层中层以下的影响也很小。机载RO可以在促进对飓风形成过程的理解方面发挥重要作用，因为使用机载系统比使用现有的太空星座更容易进行密集的目标测量。PIs将利用2010年8月热带云系统前低气压调查（PREDICT）活动期间收集数据的独特机会，这将使他们能够测试他们在热带气旋成因的数据同化方面的进展。数据同化结果应该引起PREDICT研究人员的极大兴趣，因为它们将为高分辨率模型提供更好的初始条件，用于测试有关热带扰动演变为飓风的新假设。更广泛的影响：该项目将促进机载无线电掩星的使用，以扩大研究社区，并作为飓风猎人监视任务的可行性测试，潜在地从改进的业务预报中产生直接的社会效益。这项研究活动将在台湾与美国大学的国际合作架构内，教育研究生和促进博士后研究人员的发展。将加强由4名女研究员主导的研究项目，她们将成为学生和其他年轻女科学家的榜样。