Integrated shipboard measurements of the marine boundary layer

The NOAA Environmental Technology Laboratory air-sea interaction group and collaborators at the Woods Hole Oceanographic Institution have developed a seagoing measurement system suitable for mounting aboard ships. During its development, it was deployed on three different ships and recently completed three cruises in the Tropical Ocean Global Atmosphere Coupled Ocean-Atmosphere Response Experiment as well as two cruises off the west coast of the United States. The system includes tower-mounted micrometeorological sensors for direct covariance flux measurements and a variety of remote sensors for profiling winds, temperature, moisture, and turbulence. A sonic anemometer/thermometer and a fast-response infrared hygrometer are used for turbulent fluxes. Winds are obtained from a stabilized Doppler radar (wind profiler) and a Doppler sodar. Returned power and Doppler width from these systems are used to deduce profiles of small-scale turbulence. A lidar ceilometer and a microwave radiometer are used to obtain cloud properties. Radiative fluxes are measured with standard pyranometers and pyrgeometers. A conventional rawinsonde system gives intermittent reference soundings. The system is used to study surface fluxes, boundary layer dynamics, cloud-radiative interactions, and entrainment. It has also proven useful in satellite calibration/validations. Following a description of the systems and methods, various examples of data and results are given from recent deployments in the North Atlantic, off the United States west coast, and in the equatorial Pacific Ocean.