Traditionally, the bulk of surface marine observations have come from merchant ships. There have been numerous attempts to make use of these observations to map the air-sea fluxes and understand the ocean's role in climate. However, these shipboard observations have significant errors associated with the sensors, sensor placement, and flow disturbance. Furthermore, few ships are equipped to measure the shortwave and longwave radiative fluxes.
Work has been underway to improve measurements from ships and also from surface buoys. Focused support by the National Science Foundation as part of the World Ocean Circulation Experiment (WOCE) led to extensive sensor testing and development and to the design of the Improved Meteorological system (IMET). A major, international collaboration on flux sensors and algorithms and a specific focus on in-situ intercomparisons of methods and sensors during the TOGA Coupled Ocean-Atmosphere Response Experiment (COARE) led to another significant increase in the accuracy of moored measurements. The time series of accurate surface meteorology and air-sea fluxes acquired by such buoys now provide the means to examine the performance of atmospheric models, the accuracy of climatological data sets, and the calibration and performance of satellite sensors. Examples are shown of the differences found between meteorology and fluxes from buoys and from atmospheric models and climatologies.
Work on improving the data from Volunteer Observing Ships (VOS) has also shown progress. Comparisons between high quality buoy data and the Southampton Oceanography Centre’s revision of the COADS indicate that the quality of the VOS-based meteorological and flux fields can be dramatically improved. The success of the SOC methodology is illustrated by comparing buoy data collected in the Arabian Sea for one year with the contemporaneous VOS fields from the SOC revision of COADS.
A strategy is outlined in which surface buoys would deployed at select locations around the world to provide high-quality reference sites and data from upgraded VOS are used to map the fields around the references sites. The reference sites provide the means to make regionally correct choices on the bulk formulae used with the VOS data as well as providing calibration sites for remote sensing methods. Improvements to the VOS that could be made now are outlined. In addition, work is described that will continue to improve the quality and performance of the observing system. This work includes adding turbulent flux measurements to ships and buoys, adding aspiration to the buoys, improvements to radiation sensors, protection of sensors, studies of flow distortion, and use of improved satellite communications.