This data set includes conductivity, temperature, depth (CTD), pressure, salinity, potential temperature, and density data, which were collected yearly, 2000 to 2006, in the Arctic Ocean as part of the North Pole Environmental Observatory. Investigators landed a helicopter or skiplane on the arctic sea ice and took measurements using a Seabird SBE-19 Seacat with a portable winch.They processed the ... data using the SEASOFT recipe to minimize salinity spiking and correct for a thermal lag of the conductivity cell. Certain constants were determined by empirical trial, which differed slightly for each year. The North Pole Environmental Observatory (NPEO) is a year-round, automated scientific observatory, deploying various instruments each April in order to learn how the world's northernmost sea helps regulate global climate. It consists of a set of unmanned scientific platforms that record oceanographic, cryospheric, and atmospheric data throughout the year. More information about the project is available at the project Web site, North Pole Environmental Observatory (http://psc.apl.washington.edu/northpole/). Data are in tab-delimited ASCII text format and are available via FTP.