Collaborative Research: Rainfall estimation accuracy and classification from deep underwater sound measurements

水下降雨产生的声音可用于定量测量海上降雨量。爱奥尼亚海降雨实验和正在运行的波塞冬项目是独特的数据集，它们将深水声学测量与高分辨率雷达联合收割机结合起来，可用于评价声学测量的性能。将使用来自爱奥尼亚海降雨实验（ISREX）的经降雨计校准和仪表调整的高分辨率X波段雷达（XPOL）数据估计声降雨率的准确性，随后使用业务PAL/地面雷达/风速计（POSEIDON浮标和希腊气象天气雷达网络-爱琴海和爱奥尼亚海）和存档PAL/雨量计数据（ITCZ -太平洋）进行评估。将与雷达估计的降雨分类场进行比较，对降雨的声学分类进行评价。将利用ISREX和Poseidon数据开发和测试一个模型，其中考虑到空间和时间尺度风暴结构对声学信号的影响。最后，声学数据在检索雨滴尺寸分布（降雨DSD）的性能将通过与ISREX的双极化雷达DSD检索和业务雷达测量在北爱琴海的海神浮标的比较进行评估。了解如何使用被动环境声来监测海洋环境是一个基本工具，将有助于提高我们监测全球重要气候过程的能力。特别是，降雨分布是全球水循环的重要组成部分，并在海洋表面上具有很强的声学信号，占全球降雨量的75%。探索降雨的声学信号，需要使用它来定量估计降雨，包括存在，分类，积累和雨滴大小分布。提高我们测量海洋降雨的能力对于描述全球水循环和了解气候变化的潜在趋势以及验证全球覆盖卫星传感器的估计至关重要。监测和预测气候变化对人类社会有着广泛的影响。利用来自雨的水声信号将允许在许多偏远或恶劣天气区域（大西洋和太平洋ITCZ、北大西洋等）测量降雨气候学。降雨只是海洋环境声预算的一部分的声学信号之一。其他可以测量的物理过程是风和海况（气泡）条件。对声学信号的更全面理解将允许从地下平台测量所有这些过程（雨、风和气泡），从而允许全天候、全季节的数据收集。这些包括许多新的海洋仪器平台，包括地下系泊系统，电缆网络，漂流器，剖面仪，滑翔机等海洋哺乳动物，特别是鲸鱼的被动声监测，是这些动物的生态研究的关键。最后，人类发出的声音对海洋环境的影响日益令人关切。这项工作的附带结果将是更好地监测海洋声音预算，以提供基本的基线数据，从而能够就管理海洋中产生声音的人类活动作出知情的决定。

The sound produced by rainfall underwater can be used to quantitatively measure rainfall at sea. The Ionian Sea Rainfall Experiment (ISREX) and the operational POSEIDON project are unique data sets that combine deep underwater acoustic measurements with high resolution radar and can be used to evaluate the performance of the acoustic measurement. Acoustic rainfall rate accuracy will be estimated using disdrometer-calibrated and gauge adjusted high-resolution X-band radar (XPOL) data from the Ionian Sea Rainfall Experiment (ISREX) and subsequently evaluated using operational PAL/ground-radar/buoy-anemometer (POSEIDON buoy and Hellenic Meteorological weather radar networks - Aegean and Ionian Seas) and archived PAL/rain gauge data (ITCZ - Pacific Ocean). The acoustic classification of rainfall will be evaluated in comparison with radar estimated fields of rainfall classification. A model incorporating the influence of the spatial and temporal scale storm structure on the acoustic signal will be developed and tested using ISREX and Poseidon data. Finally, the performance of acoustic data in retrieving raindrop size distributions (rainfall DSDs) will be evaluated through comparisons with dual-polarization radar DSD retrievals from ISREX and the operational radar measurements over the POSEIDON buoy in the north Aegean Sea. Understanding how to use passive ambient sound to monitor the marine environment is a fundamental tool that will contribute to our ability to monitor important climate processes globally. In particular, rainfall distribution is an important component of the global water cycle and has a strong acoustic signal on ocean surface constituting ~75% of global rainfall. Exploring the acoustic signal of rainfall is needed to use it for quantitative estimation of rain including presence, classification, accumulation and raindrop size distributions. Improving our ability to measure rain over the oceans is critical to describing global water cycle and understanding potential trends in climate change, and for validating estimates by global coverage satellite sensor. Monitoring and predicting climate change has huge broader impacts on human society. Utilizing the underwater acoustic signal from rain will allow rainfall climatology to be measured in many remote or severe weather regions (Atlantic and Pacific ITCZ, North Atlantic, etc.). Rainfall makes only one of the acoustic signals that are part of the marine ambient sound budget. Other physical processes that can be measured are wind and sea state (bubbles) conditions. A more complete understanding of the acoustic signal will allow all of these processes (rain, wind and bubbles) to be measured from sub-surface platforms allowing all weather, all season data collection. These include many new ocean instrumentation platforms including sub-surface moorings, cabled networks, drifters, profilers, gliders, etc. Passive acoustic monitoring for marine mammals, especially whales, is critical to ecological studies of these animals. Finally, the impact of human-generated sound on the marine environment is of growing concern. A collateral result of this work will be to better monitor the marine sound budget to provide fundamental baseline data to allow informed decisions regarding management of sound-producing human activities in the ocean.