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

Woods Hole Oceanographic Institution, Woods Hole MA

Investigators

Abstract

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.