Welcome to the NOAA/Pacific Marine Environmental Laboratory profiling float web site. PMEL has been active in delayed-mode salinity calibration and quality control for Argo floats since the start of the U.S. Argo program in 1999. Between May 2001 and June 2002, PMEL deployed 22 floats in the Bering Sea and North Pacific in support of Steller's Sea Lion climate studies. Starting in December 2003, PMEL began to deploy floats regularly as a contribution to the Argo program. PMEL Argo floats now comprise a substantial part of the international array. In May 2018, as part of a project with the Paul G. Allen Family Foundation, PMEL began deploying Deep Argo floats capable of profiling to the sea floor, up to pressures of 6000 dbar.
Argo floats are designed to drift at a fixed pressure (usually 1000 dbar) for 10 days. After this period, the floats move to a profiling pressure (usually between 1000 and 2000 dbar) then rise, collecting profiles of pressure, temperature, and salinity data on their way to the surface. Once at the surface, the floats remain there for under a day, transmitting the data collected by satellite back to NOAA/PMEL and allowing the satellite to determine their surface drift. They then sink again and repeat their mission.
The floats have a nominal lifetime of five or more years, and yield valuable information about large-scale ocean water property distributions and currents, including their variability over time scales from seasonal to the duration of the array.