Collaborative Research: Submersible Humidity Sensor research and development for measuring surface air humidity and evaporative flux on autonomous ocean floats

水蒸气是地球上最强和最易变的温室气体，是降水和大气凝结潜热的来源。卫星对湿度的观测很差。由于耐用传感器和观测平台的成本高昂，无法对海洋表面空气湿度进行精确观测。开发一种用于低成本无人值守海洋浮子的潜水湿度传感器，将能够在更多地点更准确地测量空气表面湿度和蒸发。更精确的湿度测量将减少蒸发和大气-海洋热量收支的最大误差。潜水浮标的湿度测量将改善季节到亚季节时间尺度的天气预报。具体而言，在热带气旋（飓风）附近的船员船只过于遥远或过于危险的条件下进行测量将改善热带气旋强度预报，挽救生命和财产。 该项目将开发和测试一种坚固的潜水表面空气湿度传感器，并将其集成到标准的自主海洋剖面浮标中。研究人员将测试湿度传感器以及经过验证的观测系统，以表征其在各种天气条件下的准确性和误差。这项研究将评估浮出水面的海洋浮子测量结果的代表性。这项研究将确定使用大体积空气动力学公式中的湿度观测值估算蒸发量的准确性。这项研究将探讨在湿温度计测量的温度瞬变是否可以用作测量蒸发通量的替代方法。湿度传感器的开发提高了“海洋科学研究界的观测、实验或分析能力”，以响应海洋技术和跨学科协调计划的目标。该奖项反映了NSF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。

Water vapor is Earth’s most potent and variable greenhouse gas, the source of its precipitation, and of its latent heat of condensation in the atmosphere. Humidity is poorly observed by satellites. Accurate marine observations of surface air humidity are prohibited by the cost of durable sensors and observing platforms. Development of a submersible humidity sensor for low-cost unattended ocean floats will allow measurement of air surface humidity and evaporation more accurately and in more locations. More accurate humidity measurements will reduce the largest error in evaporation and atmosphere-ocean heat budgets. Humidity measurements from submersible floats will improve weather forecasting on seasonal to subseasonal time scales. Specifically, measurements in conditions too remote or too dangerous for crewed vessels near tropical cyclones (hurricanes) will improve tropical cyclone intensity forecasts, saving life and property. This project is to develop and test a robust submersible surface air humidity sensor and integrate it into standard autonomous ocean profiling floats. The researchers will test the humidity sensor alongside proven observing systems, characterizing its accuracy and error in various weather conditions. The research will assess the representativeness of measurements from surfacing ocean floats. The research will determine the accuracy of evaporation estimates using humidity observations in bulk aerodynamic formulae. The research will explore whether temperature transients measured at a wet thermometer can be used as an alternative method for measuring evaporative flux. The development of the humidity sensor enhances “observational, experimental or analytical capabilities of the ocean science research community,” in response to goals of Ocean Technology and Interdisciplinary Coordination program.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.