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

热带气旋（TC）是影响美国最危险的自然现象之一。对TC强度（如风速）的测量是稀疏且不确定的。在这个项目中，我们使用一种叫做合成孔径雷达（SAR）的全天候卫星技术来收集TC中心内大气、波浪和海洋环境的高分辨率（10米）信息。第一个目标是改进气象中心内风速和降雨强度的检索。第二个目标是通过各种卫星观测扩大我们对海气交换的了解。对新SAR TC数据库的分析将最终提高对TC强度的预测。该项目将开发提取风暴大小、降雨强度和风速的方法，从而增加国家飓风中心等业务对SAR图像的信心。该项目将促进夏威夷大学马诺阿分校（UHM）与美国国家航空航天局(NASA) /位于加州帕萨迪纳的喷气推进实验室（JPL）之间的新合作，该实验室是国际知名的地球观测卫星中心。该项目将协助与美国境内卫星任务有关的未来研究项目。我们假设由sar导出的风速、风暴大小和tc内的径向结构将为海气交换提供有用的见解，并在极端强迫下约束预报模式。c波段sar对雨很敏感。相比之下，像美国宇航局计划的NiSAR这样的l波段sar对降雨不那么敏感。因此，这些雷达的互补分析将减少降雨对风速反演的污染。我们将建立C波段和l波段共极化和交叉极化sar的能力，以估计中至高风速，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风速和一个理论模型相结合，将提供一个自下而上的TC海洋-大气特征视图。我们将评估海洋对风暴强度和大小的反应。我们可以直接评估sar衍生变量和基础理论的附加效益。多种卫星技术的融合有望提供对tc内极端条件下的耦合海洋-大气系统的深入了解。改进SAR风速检索和评估卫星观测都将有助于NASA规划未来的任务，特别是那些涉及检索tc内环境信息的任务。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值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.