RII Track-4:FAST: An investigation of tropical cyclone intensity using synthetic aperture radars and complementary satellite ocean observations

热带气旋是影响美国的最危险的自然现象之一。热带气旋强度的测量，如风速，是稀疏和不确定的。在这个项目中，我们使用一种名为合成孔径雷达(SAR)的全天候卫星技术来收集关于TC中心内的大气、波浪和海洋环境的高分辨率(10米)信息。第一个目标是改进TCS内风速和降雨强度的反演。第二个目标是通过各种卫星观测扩大我们对海空交流的了解。对新的合成孔径雷达TCS数据库的分析最终将导致对热带气旋强度的预测得到改善。该项目将开发提取风暴大小、降雨强度和风速的方法，以增加国家飓风中心等行动对合成孔径雷达图像的信心。该项目将促进夏威夷大学马诺阿分校(UHM)与位于加利福尼亚州帕萨迪纳的美国国家航空航天局(NASA)/喷气推进实验室(JPL)之间的新合作，JPL是国际上著名的对地观测卫星中心。该项目将协助未来与美国境内卫星飞行任务相关的研究项目。我们假设，合成孔径雷达得到的风速、风暴大小和TCS内的径向结构将为海气交换提供有用的见解，并约束极端强迫下的预报模式。C波段SARS对降雨很敏感。相比之下，L波段的SARS，就像美国国家航空航天局计划的Nisar一样，对雨不那么敏感。因此，这些雷达的互补分析将减少降雨对风速反演的污染。我们将建设C波段和L波段的共极化和交叉极化SARS估计中到高风速的能力，特别是在降雨情况下。其他卫星技术测量海面温度、海面高度和海洋盐度。这些变量与SAR风速和理论模式相结合，将提供TC海气特征的自下而上的视图。我们将评估海洋反应，因为它与风暴的强度和大小有关。我们可以直接评估SAR衍生变量和潜在理论的附加收益。多种卫星技术的融合预计将提供对塔塔气候系统内极端条件下的海洋-大气耦合系统的洞察。改进合成孔径雷达风速反演和评估卫星观测都将有助于NASA计划未来的任务，特别是那些涉及在TC内检索环境信息的任务。这一奖项反映了NSF的法定任务，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Tropical cyclones (TC) are one of the most dangerous natural phenomena impacting the United States. Measurements of TC intensity such as wind speed are sparse and uncertain. In this project, we use an all-weather satellite technology called synthetic aperture radar (SAR) to collect high-resolution (10 m) information about the atmosphere, wave, and ocean environment within TC centers. The first objective is to improve the retrieval of wind speed and rainfall intensity within TCs. The second objective is to expand our understanding of air-sea exchanges through various satellite observations. Analysis of the novel SAR TCs database will ultimately lead to improved forecasts of TC intensity. This project will develop methods to extract the storm size, rainfall intensity and wind speeds which increases the confidence in SAR imagery for operations such as the National Hurricane Center. The project will foster new collaborations between the University of Hawai’i at Manoa (UHM) and the National Aeronautics and Space Administration (NASA) / Jet Propulsion Laboratory (JPL) in Pasadena, California, a premier, internationally renowned center for Earth-observing satellites. The project will assist in future research projects associated with satellite missions within the United States. We hypothesize that SAR-derived wind speeds, storm sizes, and radial structure within TCs will provide useful insights to air-sea exchanges and constrain forecast models under extreme forcing. C-band SARs are sensitive to rain. In contrast, L-band SARs, like NASA’s planned NiSAR, are less sensitive to rain. Therefore, the complementary analysis of these radars will reduce contamination of rainfall on wind speed retrievals. We will build the capacity of both C- and L-band co- and cross- polarized SARs to estimate moderate to high wind speeds especially under rainfall. Other satellite technologies measure sea surface temperature, sea surface height, and ocean salinity. These variables in conjunction with the SAR wind speeds and a theoretical model will provide a bottom-up view of TC ocean-atmosphere characteristics. We will evaluate the ocean response as it relates to the storm magnitude and size. We can directly evaluate the added benefit of the SAR-derived variables and the underlying theories. The convergence of multiple satellite technologies is expected to provide insights into the coupled ocean-atmosphere system under extreme conditions within TCs. Both improving SAR wind speed retrievals and assessing satellite observations will help NASA plan for future missions especially those involving the retrieval of environmental information within TCs.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.