National Oceanic and
Atmospheric Administration
United States Department of Commerce


FY 2018

Comparison of ATLAS and T-Flex Mooring Data

Freitag, H.P., M.J. McPhaden, and K.J. Connell

NOAA Tech. Memo. OAR PMEL-149, NOAA/Pacific Marine Environmental Laboratory, Seattle, WA, doi: 10.25923/h4vn-a328 (2018)

Autonomous Temperature Line Acquisition System (ATLAS) moorings have been the predominant mooring systems deployed in tropical moored buoy arrays since 1984. The present version ATLAS was used extensively in all three tropical ocean basins beginning in 2000 and continues as a significant component of the Atlantic and Indian Ocean arrays. Obsolescence of some ATLAS components, technological advancements in commercially available instruments, and a new, more capable satellite telemetry system not available when ATLAS was designed prompted NOAA’s Pacific Marine Environmental Laboratory (PMEL) to develop a new tropical mooring system, called Tropical-Flex (T-Flex). This system was designed to provide data with quality comparable to or better than that of the ATLAS system, so that multi-decadal ATLAS time series can be continued efficiently and without bias caused by changes in measurement strategy, consistent with the “Ten Climate Monitoring Principles” (Karl et al., 1996). Between 2011 and 2015 eight pairs of ATLAS and T-Flex moorings were deployed in the tropical Atlantic and Indian oceans, typically separated by a few nautical miles, to measure their relative performance in terms of real time and delayed-mode data volume, consistency, and accuracy. This report describes the design and testing of the PMEL T-Flex mooring system. We show that T-Flex meets our design criteria with both real-time and delayed-mode data being of equivalent accuracy to those of the ATLAS system. T-Flex began to replace ATLAS moorings in the Atlantic and Indian Ocean tropical mooring arrays in 2015.

Feature Publications | Outstanding Scientific Publications

Contact Sandra Bigley |