NDBC TAO: GTS Information

GTS Data Distribution

Related Links

World Meteorological Organization numbers

Service Argos

Data Buoy Co-operation Panel

GTS overview

TAO system overview (graphic)

TAO data telemetry

TAO sensor specifications

TAO sampling specifications

TAO data quality control

TRITON buoy data stream

TAO data are distributed on the Global Telecommunications System with the assistance of Service Argos and the Data Buoy Co-operation Panel. Hourly surface messages (winds, air temperature, relative humidity, and sea surface temperature) and daily averaged subsurface messages (ocean temperatures) are available in WMO code form FM 18-X BUOY with bulletin header SSVX08 KARS. TRITON data are also transmitted via the GTS. For more information on the TRITON buoys, see the TRITON web pages.

The surface messages are hourly values, but the sampling method differs between Standard and NextGeneration ATLAS systems. Details may be found in the TAO sampling page. Surface messages are generated whenever Argos receives a satellite pass, typically 2-4 times per day for ATLAS moorings.

The buoys transmit from 0600-1000, 1200-1600 local times (not GMT). The buoys transmit only 8 hours a day in order to conserve battery power and reduce telemetry cost. The morning and afternoon transmit windows coincide with satellite passes. Transmit windows for the buoys are listed below in GMT. Across the TAO array few observations are reported in real-time between 0600 and 1200 GMT.

TAO Sites	GMT transmit times
95W	1200-1600z,1800-2200z
110W	1300-1700z,1900-2300z
125W	1400-1800z,2000-2400z
140W	1500-1900z,2100-0100z
155W	1600-2000z,2200-0200z
170W	1700-2100z,2300-0300z
180W	1800-2200z,0000-0400z
165E	1900-2300z,0100-0500z

PIRATA Sites	GMT transmit times
10W	0600-1000z,1200-1600z
23W	0700-1000z,1300-1700z
35W	0800-1200z,1400-1800z
38W	0800-1200z,1400-1800z

The subsurface temperature data are available on the GTS as daily averages with a time stamp of 0000z at the end of the average period. Only one subsurface message per day per buoy is available.

As part of the data quality monitoring, NDBC identifies and informs Service Argos of data that should not be submitted to the GTS. In turn, Service Argos makes available to NDBC data which are submitted to the GTS and NDBC compares these data for consistency checks with data processed at NDBC.

Typically, about 80% to 90% of data which are received at NDBC make it onto the GTS. Due to a combination of the ATLAS sampling and transmission schedule, telemetry paths of the NOAA satellite system, and Service Argos processing time, there is a finite time lag between observations and availability on the GTS. Over half of the TAO data which are placed on the GTS are available within 3 hours or less and over 90% are available within 7 hours.